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A propylene splitter is a large distillation column used in the petrochemical industry to separate propylene (C3H6) from propane (C3H8). It is also called C3 splitter. Both propylene and propane are hydrocarbons with similar molecular weights and boiling points, but they serve very different purposes and have distinct chemical properties. The main goal of a propylene splitter is to produce high-purity propylene, which is an essential raw material for the production of polypropylene and other chemical products. The splitter relies on fractional distillation, where a feed mixture containing both propane and propylene enters the column. Through heating and distillation, propane and propylene separate based on their boiling points. Propylene splitters are typically very tall, as the height helps achieve the desired separation purity through multiple trays or packing sections. Several technologies are used to enhance the efficiency of propylene splitters, making the process more economical and energy-efficient due to the high energy demands involved. Some of the main technologies include: 1. Heat-Integrated Distillation Description: This method integrates heat exchangers within the distillation process to recycle energy, reducing overall heating and cooling requirements. Types: Dividing-Wall Columns (DWC): Uses a physical partition to enable more efficient separation in a single column instead of two. Heat-Pump Assisted Distillation: A compressor is used to increase the energy of vapor leaving the column, which is then used to reheat the bottom, reducing reboiler duty. Benefits: Reduces energy costs significantly and minimizes the number of columns required for the same separation. 2. Membrane Separation Description: Utilizes specialized membranes that selectively allow either propylene or propane to permeate, separating them based on molecular size and structure differences. Benefits: Although not a full replacement for distillation, membrane separation can reduce the load on the distillation column, leading to energy and cost savings. Limitations: Membranes are often sensitive to fouling and might not achieve the ultra-high purity levels needed for some applications, so they are typically used as a pre-separation step. 3. Adsorptive Separation Description: Uses materials like zeolites or metal-organic frameworks (MOFs) that selectively adsorb propylene over propane. Benefits: Offers high selectivity, can be effective for certain applications, and is an alternative to thermal distillation. Limitations: Adsorbent materials can be costly and may require periodic regeneration, which adds complexity to the operation. 4. Cryogenic Distillation Description: Uses low temperatures to exploit the slight difference in boiling points between propane and propylene. Benefits: Achieves very high purity for both propane and propylene. Limitations: Extremely energy-intensive due to the need for refrigeration at very low temperatures. 5. Hybrid Systems Description: Combines multiple methods, such as membranes with distillation or adsorption with heat integration, to maximize efficiency and flexibility. Benefits: Provides higher separation efficiency, flexibility in operations, and potential energy savings. The following is an example of an advanced technology utilized in real production. Distillation Process by Linde Engineering Linde Engineering uses advanced distillation technologies in its propylene splitter systems to enhance the separation efficiency of propane and propylene. One of their notable setups includes a multi-column process involving a dryer, a stripper, and a splitter, designed to maximize purity while reducing energy consumption. These systems can process both refinery-grade and chemical-grade propylene, with specific feed trays in the splitter column to optimize feed entry points based on quality. Additional purification steps, including regenerative treatment, help achieve high-purity propylene essential for downstream applications like polypropylene production. By leveraging proprietary designs and equipment like efficient trays and packing materials, Linde Engineering's technology improves separation efficiency in large-scale operations, offering more stable and energy-efficient production compared to traditional single-column splitters. This approach ensures that propylene purity levels can reach up to 98.25%, while propane is effectively removed and sent for other uses or storage. For large-scale industrial applications, this high-efficiency distillation method can be crucial for minimizing operating costs and maximizing product purity?

Manufacturers use synthesis gas, or “syngas” for fuel to produce electricity and as feedstock for production of industrial chemicals such as ammonia, methanol, and other hydrogen-rich compounds. Once isolated and purified, hydrogen from syngas is a major component in petrochemicals and oil refining. Syngas itself is a mixture primarily of hydrogen and carbon monoxide, created through the gasification of hydrocarbons in natural gas, coal, petroleum, biomass, and other feedstocks. Virtually all the hydrogen produced in the United States is produced from methane. And the cheapest, most available source of methane is natural gas.   Steam Methane Reforming Steam methane reforming (SMR) accounts for about 95 percent of the industrial hydrogen produced domestically and about half the world’s production. The process begins with the introduction of superheated (1,300 to 1,800 degrees Fahrenheit) steam and natural gas into an array of vertically hanging tubes filled with nickel catalyst. As the mixture flows through the tubes, which are heated externally (the reaction is endothermic), the methane in the natural gas reacts with the water vapor to produce hydrogen and carbon monoxide: CH4 + H2O < ——– > 3H2 + CO Ensuring the feed mixture contains excess steam ensures the maximum production of hydrogen. Plentiful steam also enables the consumption of as much methane as possible. Methane in the product is an impurity and must be stripped from the gas later in the process. Nearly complete conversion of methane has the added benefit of preventing creation of elemental carbon, which can deposit on and foul the catalyst. At present, the most widely used and cheapest method for hydrogen production is the steam reforming of methane (natural gas). This method includes about half of the world hydrogen production, and hydrogen price is about US$ 7 / GJ. Below listed are several well-known companies which provide process technology and engineering of syngas / hydrogen production on the basis of steam reforming. The number in parenthesis shows the units installed worldwide approximately.   Foster Wheeler (100) Lurgi (30) Linde (120) KBR (100) Uhde (60) Praxair (140) Haldor Topsoe (40) Technip (240) CB&I (175)   Water-Gas Shift Reaction Another reason for incorporating relatively more steam than methane in the mixture is to encourage a secondary reaction for the recovery of additional hydrogen. In this process, the mixture passes through another set of tubes of iron-chromium catalyst in a fixed-bed reactor where the molecules in the water vapor are split into oxygen and hydrogen. The hydrogen is collected along with that produced in the SMR process. The oxygen bonds with the carbon monoxide from SMR to make carbon dioxide. CO + H2O < ——– > CO2 + H2 Unlike the primary reaction, the water-gas shift reaction is exothermic, and the energy produced can be captured to partially fuel the steam-heating required in SMR. Pressure Swing Adsorption While steam methane reforming and water-gas shift reactions are quite efficient, complete reaction of methane is impossible because the reactions are subject to thermal equilibrium. This leaves some unreacted methane along with the carbon dioxide from the final product, some unreacted carbon monoxide, water vapor, and other contaminants in the gas mixture. As many operations require virtually pure hydrogen, the pressure swing adsorption process removes these contaminants. This is accomplished by pumping the mixture through cylinders filled with specially treated beads to which the unwanted gasses adhere. Once the pristine hydrogen is pumped out of the cylinders, pressure can be lowered, releasing the contaminants from the beads. They then can be flushed from the chamber. Numerous hydrogen PSA units have been installed worldwide. Leading technology licensors include:   KBR Air Products & Chemicals Linde Praxair UOP Lurgi   Conclusion A modern syngas / hydrogen plant typically has capacity range from 5 MMSCFD to 200 MMSCFD. For a 90 MMSCFD plant, the capital cost to build such a plant is estimated at approximately US$ 55 million nowadays. Average hydrogen production cost is US$ 1.60 per 1,000 standard cubic feet, or US$ 53 million per year to operate a plant of this capacity. This estimate is based on the following utility consumption. Utilities consumption per 1,000 ft3 of contained hydrogen:   Natural gas feed, million Btu LHV 317 Natural gas fuel, million Btu LHV 126 HP export steam, lbs 90 Boiler feedwater, lbs 120 Power, kWh 52 Cooling water, gal 8   Low-cost feedstock and efficient conversion of hydrogen makes steam methane reforming from natural gas the most widely used process for syngas production. Phoenix Equipment sells used hydrogen and syngas plants, and hydrogen purification components that are immediately available for purchase and relocation. Buying a used plant can save you significant capital and drastically shorten the time required to build or expand manufacturing operations.

Formaldehyde is a main raw material for manufacturing value-added chemicals and adhesives used in wood products such as particleboard and plywood. Colorless but odiferous and flammable, formaldehyde is a key component in melamine, urea-formaldehyde, and phenolic resins that have strong bonding and heat resistance qualities. Formaldehyde also is a potent preservative with uses in sterilization and embalming. Commercial producers typically use two methods to manufacture formaldehyde at scale: 1) Oxidation-dehydrogenation using a silver catalyst to achieve either the complete or partial conversion of methanol; and 2) the FORMOX process, which directly oxidizes methanol using metal oxide catalysts. In most cases, production targets a 37% aqueous solution (called formalin), but manufacturers may market concentrations as high as 57%. The solution is usually transported with methanol added to prevent polymer precipitation. Solutions that do not include methane stabilizers can avoid precipitation only when kept at 86 degrees Fahrenheit or higher. The advantage is lower shipping costs, as the higher concentrations can be diluted to the desired 37% saturation at the destination.   FORMOX: Formaldehyde Production Using Metal Oxide Catalysts Conducted in a controlled reactor environment at around 500 to 900 degrees Fahrenheit, converts nearly all the methanol feedstock into formaldehyde and water: 2 CH3OH + O2 → 2 CH2O + 2 H2O  This high efficiency – 98% or higher conversion – reduces waste and requires less of the expensive starter material than the silver catalyst process to achieve the same volume of formaldehyde. FORMOX introduces feedstock containing lower methane concentrations than the surrounding steam and the steam and air to ensure a stable reaction and eliminate the possibility of explosion. The process creates highly purified formaldehyde containing only trace amounts of carbon monoxide, dimethyl ether, carbon dioxide, and formic acid byproducts. The reaction works by injecting vaporized methanol, air (and sometimes tail gases from previous cycles) over the iron oxide catalyst inside the reactor. As the methanol reacts with oxygen inside the tank, transfer fluid captures the heat generated and uses it to boil water and create steam for powering other industrial processes. Meanwhile the gases – mostly newly converted formaldehyde travel to an absorption chamber, where they condense and are absorbed into water fed into the chamber. An anion exchange reduces the formic acid content of the aqueous solution, the resulting product may contain up to 55% formaldehyde by weight, depending on the quantity of water introduced into the absorption chamber.   Formaldehyde Production Using Silver-catalyzed Methanol Heating the feed stock to approximately 700 degrees Celsius increases the rate and equilibrium of the endothermic dehydrogenation reaction sufficiently to convert 97% to 98% of the methanol. After cooling to shut down undesirable side reactions, the vaporous mixture enters an absorption column, which elutes the formaldehyde to 40-55% formaldehyde by weight, with small amounts of aqueous methanol and formic acid (created from excess oxygen present during formaldehyde production). Requiring reactor temperatures of 1,100 degrees Fahrenheit and above, this process converts some of the methane in the same manner as the FORMOX process above, but also simply extracts hydrogen from the methane feedstock to product formaldehyde through a different, anaerobic reaction: CH3OH → CH2O + H2  This direct dehydration is less efficient than FORMOX, so it demands more methane to be fed into the reactor in order to return similar concentrations and volumes of the finished formaldehyde. So, why would manufactures use silver rather than the more efficient metal oxide catalyzation reaction? Despite higher methanol feedstock consumption, silver-catalyst formaldehyde production can deliver lower-cost products than iron oxide operations. This cost savings may offset efficiency losses, especially for smaller plants that can obtain methane cheaply to convert it in one of two subprocesses:    (Nearly) Complete Conversion With conversion as high as 98%, this process begins by heating the feedstock to approximately 1,200 degrees Fahrenheit to optimize the rate and equilibrium of the endothermic dehydrogenation reaction. Conversion occurs at a much lower temperature, however, and creates trace elements of carbon monoxide, carbon dioxide, hydrogen, and water along with the formaldehyde. Rapid cooling shuts off potential side reactions that can cause the formaldehyde to deteriorate. Absorbed into water, the formaldehyde creates a 40 to 55% aqueous solution, which also contains tiny amounts of methanol and formic acid, which are formed using the excess oxygen not used in the formaldehyde reaction. Incomplete Conversion and Distillate Recovery  The reactor heats the methane-containing feedstock to approximately 1,300 degrees Fahrenheit to forestall any unwanted secondary reactions. The reaction uses the oxygen in the chamber to convert 77 to 87% of the methane. Once cooled and absorbed into water, the solution contains about 43% formaldehyde, along with the 13 to 23% unconverted methane, formic acid, and other byproducts. Equipment removes the methanol and recirculates it into future conversion cycles. The next step is to further remain the solution to reduce the formic acid content, boosting its formaldehyde concentration to as much as 55% and its yield to around 90%. Comparing and Contrasting Methods and Applications As noted, manufacturers may choose FORMOX to capture formaldehyde reaction efficiencies or they may choose silver catalyzation to take advantage of lower operating costs. Plant operators should consider several other variables in deciding which process makes sense in their situation:   Plant Capacity – For low-capacity facilities, producing up to 5,000 tons per year of formalin, the silver process is more economical. This process is less technical and requires fewer upfront costs, making it an attractive option for smaller operations. Larger plants producing up to 100,000 tons per year, however, likely should use the iron oxide catalyst process. Although this process requires higher capital expenditure on technology, the added capacity helps to offset these costs. The larger scale allows for greater economies of scale, improving the overall efficiency and profitability of the operation. Ultra-large operations may become inefficient due to excessively large gas conducts required for the metal oxide process. These producers should consider splitting production among medium-sized units that can capture all the metal oxide catalyzation efficiencies. Catalyst Cost: Silver catalysts must only last a few months, but because they can be fully regenerated, their overall cost is less than iron oxide catalysts that can last for over a year, but whose salvage value is limited to their molybdenum contents. Tail Gas Processing: The silver process generates tail gases containing approximately 20% combustion-facilitating hydrogen. Combustion creates steam and burns off carbon monoxide and other environmentally harmful organic compounds. Conversely, the tail gas produced in the iron oxide process is not flammable due to its low dimethyl ether, carbon monoxide, methanol, and formaldehyde content. Burning these gasses can only be accomplished by using a catalytic incinerator or adding fuel, making the process more complicated and costly. Steam Generation: The metal oxide process produces sufficient steam heat that manufacturers can export and use to power other processes, potentially providing energy efficiency and cost savings. Methanol rectification fully consumes the little steam generated in the silver-catalyst operation. Sometimes, the steam produced is insufficient and the reaction can only be completed by adding more. Product Purity: Metal oxide catalytic production yields formaldehyde with significantly less formic acid, heavy metals and unreacted methanol, and other impurities compared to the silver process. Industries increasingly require formaldehyde solutions with zero methanol and concentrated (up to a 4:1 formaldehyde to water ratio), urea-stabilized solutions, which can only be made in metal oxide-catalyst operations.    Phoenix Equipment stocks a full range of formaldehyde production equipment to help manufacturers start or scale operations. Whether you need reactors, absorption towers, boilers, evaporators, or a fully operational plant, we can help you get up and running in a fraction of the time and cost of buying new equipment. If you don’t see what you want on our website, contact our experts. We engage with suppliers and motivated sellers around the world and would be happy to put the word out.  

Falling feedstock prices, greater efficiency, and an increased worldwide demand as more economies emerge all present lucrative opportunities for the conversion of natural gas to liquid synthetic crude oil. That’s because much of the world’s natural gas – up to one-third by many estimates – are located in remote deposits. Liquefaction of natural gas makes it more economical to transport via tanker or pipeline and to store for future refinement and use. Small, onsite gas-to-liquid (GTL) plants will make tapping these “stranded gas” deposits profitable. Natural gas has proven the best feedstock for creating crude oil alternatives through the industry standard Fischer-Tropsch process, topping coal in purity, handling, and ease in conversion to syngas, which is required for efficient conversion to synthetic crude.   GTL Plant Benefits The synthetic oil GTL plants produce is virtually interchangeable with conventional oil, both as refined transportation fuels and petrochemicals. Technological breakthroughs in catalyst design and reactor engineering, as well as more efficient chemical processes, have reduced start-up and operating costs to the point where they are becoming competitive. GTL is becoming more attractive for a number of reasons: Ecology – The GTL process creates more homogeneous mixtures, with less sulfur, nitrogen, and aromatics, making combustion more consistent and complete, so carbon emissions are reduced. Supply – Natural gas, the preferred GTL feedstock, is plentiful compared to oil and coal. Developed and emerging economies can use technology to literally fuel their growth. Feedstock Cost – The abundance of localized stranded gas pockets around the world and the greater accessibility of shale gas in the United States has helped keep the cost of natural gas low. The ability to transform natural gas into higher-value fuels for transportation has generated significant interest in monetizing natural gas. Low feedstock costs now can offset many of the higher startup and operating costs associated with GTL plants. National Security – Exploiting natural gas to produce the inputs needed to manufacture oil-based products can reduce dependence on oil imports that can be withheld as a diplomatic, negotiating, or strategic weapon. Industry Outlook While significant challenges remain in order to maximize production efficiencies, revenues, and profits, investors in gas-to-liquid processing have the potential to get in on the ground floor of a lucrative industry. Major players such as Shell and Exxon-Mobil are investing heavily in GTL technologies that eventually will bring improved efficiencies, lower costs, and develop markets. These markets are expected to become ever more segmented, as countries strive to: Develop domestic industries Reduce dependence on imports Build industrial and transportation infrastructures Create jobs Gas-to-Liquid Processing As mentioned above, the conversion of natural gas into liquid petroleum products involves the Fischer-Tropsch (FT) synthesis, but the first part of the conversion involves the production of syngas through a reformer that converts natural gas to base reactants. Synthetic gas, “syngas” is a mixture of hydrogen and carbon monoxide produced by the high-temperature reaction between the methane in natural gas and steam. It is commonly used in the production of ammonia. In step two, the FT process converts syngas to synthetic hydrocarbon in the form of paraffins. The final step, called “upgrading,” injects more hydrogen into the waxy, long-chain paraffins under mild hydrocracking conditions. The hydrogen breaks the chains into diesel, kerosene, naphtha, and other valuable products while removing impurities such as olefins.   Gas-to-Liquid Plant from Phoenix Phoenix Equipment offers used GTL and syngas processing equipment for startup and expanding operations. Phoenix recently acquired a complete 7 million standard cubic feet per day (18,500 normal cubic meters per hour) plant offering turnkey entry into the industry. Built-in 2016 and operational as a demonstration plant for only a few months, this Hydro-Chem (now Linde) manufacturing facility is immediately available for purchase. The ready-to-commission plant includes two reforming units, feed heater and superheater, desulfurizer, steam generators and drums, and more. The equipment provides all you need to produce syngas from natural gas or biomass and then convert it to naphtha and diesel with the Fischer-Tropsch process. For more information view the plant liquidation, call Phoenix Equipment at (732) 442-6990, or contact our sales team and we would be happy to assist you.

In this article, we will show that a steam methane reformer (SMR) is critical in the production processes of hydrogen, ammonia, and methanol; as all three use the raw syngas produced by an SMR upstream in their synthesis.   Syngas Production In what is called steam methane reforming, high-temperature steam (700°C–1,000°C) is used to produce raw syngas from a methane source, typically natural gas. Using a steam methane reformer (SMR), methane reacts with steam under 3–25 bar of pressure in the presence of a catalyst to produce hydrogen, carbon monoxide, and a relatively small amount of carbon dioxide. The resulting gas mixture is called synthesis gas, or syngas for short; and is the raw ingredient in hydrogen production, ammonia synthesis, and methanol synthesis.   Hydrogen Production Subsequently, in what is called the "water-gas shift reaction," raw syngas and steam are reacted using a catalyst to produce carbon dioxide and more hydrogen. In a final process step called "pressure-swing adsorption," carbon dioxide and other impurities are removed from the gas stream, leaving essentially pure hydrogen.   Ammonia Synthesis Ammonia is produced at an industrial scale through the synthesis of nitrogen and hydrogen in an ammonia synthesis loop in what is called the Haber-Bosch process. The hydrogen and nitrogen are mixed at a 3:1 ratio. In most processes the reaction takes place on an iron catalyst. The reaction pressure is normally in the range of 150 to 250 bar‚ and temperatures are in the range of 350°C to 550°C. Generally speaking, an ammonia plant will have feed purification, a primary and secondary SMR, water-shift converter, carbon dioxide removal, methanation, and finally an ammonia synthesis section. For a more in-depth view, please find our ammonia article below: https://www.phxequip.com/resource-detail.56/ammonia-production-technologies.aspx   Methanol Synthesis                    Methanol is produced by reacting carbon monoxide and carbon dioxide with hydrogen using a methanol synthesis loop. It processes raw syngas made from a SMR and gas recycled from the secondary reformer in the presence of a zinc / copper catalyst. The partially reformed gas stream from the primary reformer is sent to the secondary reformer where it is reacted with oxygen and most of the remaining methane converted to synthesis gas, which is called recycle gas and is sent back to the primary reformer for processing. A standard methanol plant consists of the following process section: feed purification, steam reforming, syngas compression, methanol synthesis (conversion/reaction) and methanol distillation. Please find a more detailed explanation of methanol production in our article below: https://www.phxequip.com/resource-detail.16/the-3-phases-of-large-scale-methanol-production.aspx   Conclusion Syngas is a key feedstock in the production of hydrogen, ammonia, and methanol. Almost all of this syngas is produced by a steam-methane reformer (SMR), so regardless if you’re planning to build a hydrogen, ammonia, or methanol plants -- SMRs are the heart of the facility. Furthermore, due to the inherent similarities between ammonia synthesis loops, and methanol synthesis loops, engineering firms have successfully converted ammonia plants into methanol plants, and methanol plants into ammonia plants. So, there are multiple path to save on capital costs by purchasing a used plant.   Link to Syngas/Hydrogen Plants: https://www.phxequip.com/plants-subcategory.140.0/hydrogen-hyco-syngas-plants.aspx Link to Ammonia Plants: https://www.phxequip.com/plants-subcategory.140.0/hydrogen-hyco-syngas-plants.aspx Link to Methanol Plants: https://www.phxequip.com/plants-subcategory.55.0/methanol-plants.aspx  

A Common Plant Liquidation Scenario Your company has made the tough decision to close a plant. This plant was running for years, and the company paid a lot to have it built, paid everyone’s salaries, and maintained or even modernized all of the production assets over the plant’s life but the plant needs to be sold off for one reason or another. Your company has called upon you to recover as much dollar as you can to help keep the organization alive, and better yet, healthy, in what is a constant battle in the marketplace. You’ve either: Have spent months, maybe even years trying to find a buyer that would operate the plant in place, without any success, while the plant’s assets lose value every passing day. Or, you can’t sell it to another company, as you are one of the few suppliers of the product the plant makes, and you don’t want to create a competitor, or improve a competitor’s position. Or, the plant is on leased property that is costing the organization a lot of money without getting any of it back from produce from the plant, like being a lessee of a field where all the fruit trees are dead. You are in a situation where you can’t sell the plant for operation in place to another company, so you have to find another way to recover as much money as you can. Conventional wisdom says to just have the plant demolished, and hope the scrap value of the assets cover the work, and if you’re lucky, put some cash in the organization’s pocket. It doesn’t feel good, but what else can you do? Welcome Phoenix Equipment: Your Plant Dismantlement & Relocation Services Partner Phoenix Equipment’s plant dismantlement and plant relocation services give you the options you need. You are not fenced in to a one-size fits solution. We start with a transparent discussion, outlining our services, and then letting you decide if our services are the right fit for you. From the very first conversation onward, Phoenix works with you as a partner, and gives you a hand up on maximizing value recovery. Phoenix Equipment is in the unique position of buying and selling entire chemical plants for relocation, while also having a strong position in selling chemical process equipment a la carte. This gives you access to a worldwide marketplace of chemical plant and equipment buyers, and Phoenix either sells the assets on an agreed upon commission, giving you access to Phoenix’s powerful marketing abilities and superior exposure due to our high ranking capabilities on Google and other major search engines. Phoenix also does direct active marketing campaigns, and has an extensive book of business; instantly giving you access to thousands of buyers. If you have a tight timeframe for recovery, Phoenix can prepare a proposal to either: Buy the plant outright. Or, liquidate the plant, and give you a turnkey package where Phoenix dismantles the site and gives you cash in great excess over the scrap value. Learn more about the number of plant selling options Phoenix offers to see which solution is the best for your business. The Plant Dismantling and Relocation Team that Will Earn You Top Dollar Phoenix has 30+ full-time employees dedicated to plant demolition and plant dismantlement, and a full-time sales and marketing team. Phoenix’s management and project managers all have more than 10 years of experience with the company, and in most cases over 20 years of industry experience. Phoenix has performed turn-key asset recoveries for over 100 companies, with a EMR rating of under one (-1) for over fifteen years. A Trusted Partner for Over 40 Years Limit the time and resources you spend decommissioning the plant and trying to recover value, Phoenix’s safe and proven approach to plant dismantling, relocation, and asset recovery requires minimal involvement from you after we have agreed on an approach. You are freed up to focus on your other business objectives, while Phoenix turns your old plant into working capital. Phoenix can safely dismantle the plant and get you maximum value for the assets (process technology, process plant, process equipment and scrap materials), and can provide you a no obligation evaluation that will include proposed scope of work and deal terms. Contact Phoenix today to stay above the curve in both cash recovered and project deadlines.

Hydrogenation is a billion-dollar industry. Hydrogenating means to add hydrogen to something. According to Haldor Topsoe, hydrogenation comprises 48% of total hydrogen consumption, 44% of which is for hydrocracking and hydrotreating in refineries , and 4% for hydrogenation of unsaturated hydrocarbons (including hardening of edible oil) and of aromatics, hydrogenation of aldehydes and ketones (for instance oxo-products), and hydrogenation of nitrobezene (for manufacture of aniline).   Hydrocracking & Hydrotreating Industrially, hydrotreating and hydrocracking are performed in down flow ‘trickle bed reactors’, where the gas and the liquid feed are sent concurrently through a fixed bed plug flow reactor. Although the flow pattern in the reactor can be reasonably approximated, the observed kinetics in such a trickle bed reactor are quite often affected by minor unplanned oscillations in the flow. How the gas and liquid collide and mix together affects the end product characteristics, so industrial reactor simulation models require that these phenomena be accounted for. Instrumentation, coupled with advance simulation software, is integrated so that operators can keep track of the mass flow of each chemical, interphase mass change, and heat transport in the trickle bed reactors.   Food Industry Hydrogenated fat is usually a substitute to butter fats. High costs of butter fat and its poor storage stability led to using hydrogenated fats and oil. The unsaturated fatty acid content of triglycerides is changed by hydrogenation into hydrogenated oils by the saturating of their carbon double bonds (C=C) and converting them to single carbon bonds (C-C) in the presence of catalyst, usually Nickel. Hydrogenation accomplishes two things: 1) It increases the melting point of the oil or fat. 2) Resistance to oxidation and flavor deterioration. Hydrogenation process depends on several parameters: type of catalyst, pressure, speed of agitation, and temperature. Unsaturated food oil is pumped in a pressure vessel called an hydrogenator. This must be equipped for good agitation, for heating and cooling, and with suitable openings for oil, hydrogen, and sampling. Vacuum is applied on the headspace and heating started. Vacuum prevents oxidation of oil when heated. Catalyst is weighed into a catalyst mix tank, slurried with a small amount of oil, and when the reaction temperature is reached the catalyst is pumped into the reactor, mixed and then hydrogen is added to the desired pressure. Hydrogenators allow the hydrogen to accumulate in the headspace above the oil with recirculation provided by vortex action of the agitator. During hydrogenation, water is circulated through the cooling coils to counteract the heat of reaction since hydrogenation is an exothermic reaction, and later for cooling prior to filtration. After cooling, the nickel catalyst is then removed from the hydrogenated fat by filtration.   Chemical & Pharma Synthesis Aniline is produced by the hydrogenation of nitrobenzene. Nitrobenzene is fed with hydrogen into a tubular plug-flow reactor containing a noble metal (i.e. platinum) catalyst supported on carbon. The hydrogenation is carried out in the liquid phase. The majority of the aniline produced globally is utilized in the manufacture of methylene diphenyl diisocyanate (MDI). To make MDI you react aniline with phosgene, in a process called Phosgenation. Phosgene is made by reacting carbon monoxide with chlorine, and like the hydrogen used in the hydrogenation process, the carbon monoxide used to make phosgene comes from a steam-methane reformer (SMR). In the Pharma industry, the hydrogenation process is particularly useful in the production of chiral and commonly hydrogenators are used, providing organic compounds like R-3-Quinuclidinol (C7H13NO) used in the manufacture of intermediates used in APIs (activated pharmaceutical ingredients).   Conclusion The hydrogenation market brings in over billions of dollars in revenue each year. For this reason, people buy and sell used hydrogenation equipment, and since this equipment is useful across multiple applications, hydrogenation equipment such as hydrogenators hold their value in the second-hand market. Please find our inventory of hydrogenators below:   https://www.phxequip.com/plants-subcategory.49.0/hydrogenation-plants.aspx

Thermoplastics are a class of polymers, that with the application of heat, can be softened and melted, and can be processed either in the heat-softened state (e.g. by thermoforming) or in the liquid state (e.g. by extrusion and injection molding). Over 70% of the plastics used in the world are thermoplastics, and the two most commonly used thermoplastics are both olefins, compound made up of hydrogen and carbon that contains one or more pairs of carbon atoms linked by a double bond. These two olefins are polyethylene and polypropylene.   Polyethylene Polyethylene is a tough, light, flexible synthetic resin made by polymerizing ethylene, chiefly used for plastic bags, food containers, and other packaging. It may be of low density or high density depending upon the process used in its manufacturing. It is resistant to moisture and most of the chemicals. It can be heat sealed and is flexible at room temperature (and low temperature), and in additional to its material properties, its low cost contributes to the popularity and high demand of the material. Major Applications • Low-density polyethylene (LDPE), recyclable plastic no. 4, is flexible and is used in the production of squeeze bottles, milk jug caps, and retail store bags.• Medium-density polyethylene (MDPE) is used for sacks, gas pipes, fittings, and packaging film.• High-density polyethylene (HDPE), recyclable plastic no. 2, is commonly used as milk jugs, liquid laundry detergent bottles, outdoor furniture, margarine tubs, grocery bags, drinking water distribution systems, and water drainage pipes. • Ultra-high-molecular-weight polyethylene (UHMWPE) is tough and resistant to chemicals. It is used to manufacture moving machine parts, bearings, gears, artificial joints, and bulletproof vests. Production Process Polyethylene is made by the polymerization of ethylene, which is the reacting of ethylene molecules together to form a chain of ethylene molecules. The two primary feedstocks for ethylene production are naphtha and natural gas liquids (ethane, propane, butane). Natural gas liquids are used in countries like the United States where natural gas is abundant, and naphtha is used commonly in Asia where producers have access to cheap byproduct naphtha. Ethane is a major bottleneck chemical, so many refineries have furnaces to take the over-abundance of ethane and convert it into the more valuable ethylene.The first step in the production of ethylene is to take the feedstock and crack it into ethylene in a furnace. This process is called pyrolysis. Also called steam cracking, pyrolysis is the thermal cracking of petroleum hydrocarbons with steam. The production process for the two most common types of polyethylene: low-density polyethylene and high-density polyethylene, will be described below. Low-density polyethylene (LDPE) is made from ethylene gas under extremely high pressures (up to about 3,500 bar, or 50,000 psi) and high temperatures (up to about 350 °C [660 °F]) in the presence of oxide initiators, which results in a polymer structure with both short and long branches. Because the branches prevent the polyethylene molecules from packing closely together in stiff, hard crystalline formations, LDPE is a very flexible material. Its melting point is approximately 110 °C (230 °F). Principal uses are in packaging film, trash and grocery bags, agricultural mulch, wire and cable insulation, squeeze bottles, toys, and housewares. High-density polyethylene (HDPE), on the other hand, is manufactured at low temperatures and pressures, using metallocene and Ziegler-Natta catalysts or activated chromium oxide (also known as a Phillips catalyst). The lack of branches in its structure allows the polymer chains to pack tightly, resulting in a highly crystalline, dense material of high strength and moderate stiffness. With a melting point more than 20 °C (36 °F) higher than LDPE, it can withstand repeated exposure to 120 °C (250 °F) for sterilization. Products include blow-molded bottles for milk and household cleaners; blow-extruded grocery bags, construction film, and agricultural mulch; and injection-molded pails, caps, appliance housings, and toys. Major Technology Providers Ethylene Plants: KBR; Technip; Linde; Shaw, Stone & Webster; and Lummus. Polyethylene Plants: Sasol; Formosa Plastics; Ineos; and Odebrecht.   Polypropylene Polypropylene, recyclable plastic no. 5, is useful for a plethora of products such as microwave and dishwasher-safe plastic containers, reusable plastic food containers, sanitary pad lining and casing, diaper lining, carpets, ropes, plastic moldings, piping systems, filters for gases and liquids, car batteries, and insulation for electrical cables. Polypropylene sheets are used for stationery folders and packaging and clear storage bins. In medicine, it is used in hernia treatment and to make heat-resistant medical equipment. Although relatively inert, it is vulnerable to ultraviolet radiation and can degrade in direct sunlight. Polypropylene is not as impact-resistant as the polyethylenes (HDPE, LDPE). It is also somewhat permeable to highly volatile gases and liquids. Production Process Traditional productions methods are the naphtha steam cracking process and propane dehydrogenation. The naphtha steam cracking process is very similar to the steam cracking process of natural gas liquids; while propane dehydrogenation is a very different process that involves mixing fresh propane feed is with recycled propane and optionally also with recycled hydrogen gas and is fed into a heater to be heated to over 540°C (1000°F) and then enters usually three or four reactors. The propylene-rich reactor effluent is compressed, dried and sent to a cryogenic separator where hydrogen is recovered. The olefin stream then goes to an ethylene column where light-ends are removed prior to the propane-propylene splitter where propylene is recovered. Unconverted feedstock is recycled and combined with the fresh feed.Propylene could also be generated in FCC (fluid catalytic cracking) units but its yield is relatively low. Another approach is to integrate the propylene production process into refinery or petrochemical plants, and use lower value chemicals made in the process, for the catalytic cracking of mixed C4 olefins (olefins with 4 carbon atoms) and higher carbon olefins. Major Technology Providers Propylene Plants: Lummus Technology; Servomex; Honeywell UOP; and Mitsubishi Chemical. Polypropylene Plants: LyondellBasell; Borealis; Chisso; Grace; Mitsui Petrochemical; Krupp Uhde; Linde; Yarsintez/Snamprogetti; Novolen Technologies; Rexene; and Sumitomo Chemical.   Conclusion Demand for thermoplastics exceeds billions of dollars globally, and the two most common originate from hydrocarbons from refineries such as naptha, ethane, propane, and butane. If you already have a refinery, or access to cheap feedstock, or, for example, as a by-product from another chemical plant -- the return on investment of a used thermoplastics plant can be less than 3 years depending on the particulars of your local/global economic positioning and utility costs. Please find a link to our ethylene plants on offer below: https://www.phxequip.com/plants-subcategory.36.0/ethylene-plants.aspx

Sulphonation Sulphonation is key to making the sulfates used as key ingredients in soaps and detergents, and manufactured in a process called “Sulphonation”. Production Process Fundamentally, Sulphonation is based on the reaction between a sulphur trioxide stream diluted in air and an organic base. The reaction is carried out in a stainless-steel multi-tube film reactor where the sulphur trioxide stream and the organic base are conveyed in co-current, for a reaction time necessary for a sulphuric group to react with the base and to form an additioned molecule. This molecule has an electrically neutral end (the hydrocarbon chain), which is hydrophobic, and a hydrophilic polar end (the sulphuric group). This dual property is the key behind the detergent behavior of the LABSA (linear alkyl benzene sulphonic acid), and its ability to modify the water surface tension Product quality control Color is a critical property for the commercial value of the sulphonated organic base. Color may be impaired by several factors, including reaction temperature. Since the reaction is fairly exothermal, in order to hold constant temperature, the reactor tube bundle is submerged in circulating cooling water under temperature control. Sulphuric acid content, free oil content, and density are other quantifiable parameters of product quality. Common section of the production process The sulphuric stream production is a common feature of all sulphonation processes. The sulphuric stream is manufactured by a process similar to the sulphuric acid (H2SO4) production. Solid Sulphur is the raw material, usually in pellet form at high purity as produced by the Claus process, which is the partial oxidation of sour gas, any gas such as natural gas with a significant amount of hydrogen sulfide. Sulphur is molten by steam in a jacketed tank, then is pumped to a combustion furnace where is burnt in a large excess of air with formation of sulphur dioxide. It is critical for the sulphur dioxide stream to be cooled down for the next processing step. Conversion and sulphonation The cooled down Sulphur dioxide is then conveyed to a multi-layer catalytic reactor, where sulphur dioxide (SO2) is converted almost completely to sulphur trioxide (SO3). Further cooling and filtration of this stream is required before being reacted with the organic base in the multi-tube film reactor. Under strict control of temperature and of flow rate, the organic base is fed to the sulphonation reactor. Software and hardware enable the operator to carry out the control tasks automatically or flexibly bring such key parameters under manual control. SLES (sulphonated ethoxylated lauryl alcohol) A LESA (type of acid) stream is neutralized in a loop where the reactor output is treated with a caustic soda solution and is subject to a homogenizing process in a dedicated piece of equipment achieving lump-free and stringent homogenization specifications as necessary for its application in the cosmetic industry. A special cooler is used to handle the significant amount of heat developing out of the neutralization reaction; then, for color adjustment, pH adjustment, deareation and product ageing -- additional on-stream equipment and injections are used. Deareation consists in the removal of small air bubbles forming during the various atmospheric processes, in a degasifier working under vacuum, providing a crystal appearance to the SLES paste. 1,4 – Dioxane, eventually produced as an undesired by-product of the sulphonation reaction, can be removed by further optional treatment. Dioxane is stripped out of the paste in a vacuum film evaporator where also deareation occurs simultaneously. AOS (sodium alpha olefin sulfonate) A supplementary treatment is involved in the production of Sodium Alpha Olefin Sulfonate (AOS), named “hydrolysis”, in addition to the neutralization of caustic soda from the acidic reactor output. The neutralized AOS stream is heated up to high temperature, homogenized and aged per proper time specifications ensuring the complete conversion of Sultones to surfactant compounds. After a final cooling, the product is ready for storage or packing. Technology providers: Chemithon Desmet Ballestra Lion Corp Marsina Engineering Mazzoni Meccaniche Modeme Fatty Acid & Glycerin Production Another critical part of the soap supply chain is oleochemical plants. Please find the below link to learn more about fatty acid and glycerin production. https://www.phxequip.com/resource-detail.64/edible-oils-fats-refining-process.aspx Conclusion Proper attention to production parameter is key to the quality of the intermediaries produced in the sulphonation process. It might be best to consult with multiple technology providers to get the results your customers require.

Whether you’re planning to upgrade your production machinery, downsize your operation, close a plant, or get rid of excess inventory, one thing is certain; you will end up with unused equipment. Whatever your situation, there are several great reasons to sell surplus industrial and process equipment, and a liquidation service may be your best option. Selling your chemical or industrial processing machinery, production lines, or entire plants to used industrial equipment dealers is often preferable to private-party sales or simply junking it. Professional surplus equipment buyers allow you to sell large quantities quickly, alleviating you of the hassle involved in finding customers, negotiating terms, storing equipment, and arranging deliveries. Here are a half-dozen reasons to sell to a dealer: 1. Cash in Hand Reputable equipment liquidation service providers can buy single pieces of machinery, truckloads of components, or entire plants. Selling industrial equipment to a dealer is easy, fast, and puts cash in your hand quickly. The sale of your surplus equipment recoups some of the capital you originally invested, giving you needed capital to invest in other areas of your business. Your return will vary depending on the type of equipment you have to sell, its age, and condition. So why let your unused process equipment continue to depreciate? Get a free quote today, sell your idle equipment, and get paid top dollar for it. 2. Free Up Wasted Space Unused processing equipment takes up a lot of room, occupying real estate that could be used for finished product inventory, shipping and receiving, production staging, and other mission-critical items and tasks. These large pieces of equipment and machinery are often encumbered with cords and hoses that pose tripping hazards and sharp edges that can injure workers and damage other, more useful equipment and raw materials. Holding onto excess inventory costs money in several ways: Carrying Costs – Warehousing is expensive, whether you rent space at a remote location at rates up to $7 per square foot, or pay for utilities, overhead, and personnel to store it onsite. Insurance – The more stuff you have, the more it costs to protect against loss, theft, and vandalism. Obsolescence – The longer you hold onto equipment you don’t use, the greater the risk that it will depreciate in value. Inefficiency – Working around unused equipment costs warehouse workers time. They have to store parts wherever they can find room. Take back control of your warehouse or workspace by getting rid of the equipment you no longer need. 3. Lower Maintenance Costs When you sell industrial equipment, you also rid yourself of high maintenance costs. Even if you have decommissioned the equipment, you still have to keep it in working order if it is to retain its value or in case it must be pressed back into service as a replacement or in a new or reopened plant. Labor, parts, lubricant, cleaning, and other repair and maintenance costs add up quickly, especially when the equipment isn’t at work generating revenue. Dealing with a surplus equipment buyer can get these expenses off your books, and put your well-paid maintenance crews to work taking care of equipment that’s actually productive. 4. Environmental Stewardship Taking care to dispose of used components is the ecologically responsible thing to do. Rather that consigning your equipment to a landfill, you can sell it to an industrial equipment dealer who will see that it is recycled, repurposed, and reused, reducing the need to manufacture new equipment. Keeping the metals and electronics out of municipal dumps eliminates health and environmental hazards. So why not make the environmentally friendly decision to resell and repurpose the equipment you will no longer use? Fulfill your company’s social responsibility commitments and establish your company as an industry leader in the going green movement. 5. Business Contacts Equipment liquidation services make strong business contacts and trading partners. When you are looking to sell your equipment, you establish relationships that can pay off handsomely down the line. When you need to buy or sell industrial equipment in the future, you know who to contact and who to trust. Additionally, when you find a reputable surplus equipment buyer, you can count on them to be on the lookout for specialty or hard to find equipment you need. Finally, your dealer can put you in contact with other surplus equipment buyers and people in the industry, with whom you may form mutually profitable arrangements. 6. Tax Benefits and Decommissioning Credits The profit you generate by selling used industrial equipment is taxable, but the net tax benefits almost always outweigh the negatives. In many cases, while your sale to a used industrial equipment dealer may approach market value, it is likely to fall short of book value. You can claim a write-off for the difference between the price you get and book value. You may be entitled to other tax incentives as well, just ask your accountant. If you have taken a reserve for the cost of decommissioning equipment and closing plants, selling to surplus equipment buyers offers the opportunity to tap into those funds. By allowing you to reverse those reserves, an equipment liquidation service essentially pays you to regain the money you put in escrow for these purposes. Given all the financial, efficiency, and intangible benefits that go along with selling unused equipment to a surplus equipment buyer, there is little reason to hold onto industrial and process equipment and machinery.   Phoenix Equipment prides itself on fair dealing and building long-term relationships with clients. As the country’s leading buyer and seller of used industrial and chemical processing equipment, Phoenix offers a one-stop solution for liquidating single machines or entire production facilities. We can handle the entire transaction, including decommissioning, dismantling, and transporting equipment across town or around the world. In addition to outright purchase of plants and equipment, we can broker your sales as your marketing agent or liquidation or auction manager. To discuss the selling option that works for you and how you can earn cash for your surplus equipment,contact Phoenix today.

Vinyl chloride is an organochloride with the formula H2C=CHCl that is also called vinyl chloride monomer, VCM or chloroethene. This colorless compound is an important industrial chemical chiefly used to produce the polymer polyvinyl chloride (PVC). Nearly all production of VCM is based on ethylene, which is first reacted with chlorine to make ethylene dichloride (EDC). There are two routes commonly used to make EDC: direct chlorination using pure chlorine and ethylene, and oxychlorination in which the ethylene reacts with chlorine in hydrogen chloride. The EDC is then converted to VCM by thermal cracking and the hydrogen chloride by-product can be recycled to an oxychlorination plant to make more EDC. Many EDC/VCM complexes use an integrated chlorination-oxychlorination process which proceeds in three stages: the chlorination of ethylene in the liquid or vapor phase to make EDC; the thermal cracking of EDC to form VCM and hydrogen chloride; and the oxychlorination of ethylene with recycled hydrogen chloride to make more EDC. VCM is sent through a catalyst-containing reactor where polymerization occurs. Chemicals cause the VCM molecules to react until they link together into Polyvinyl Chloride (PVC). The linking of VCM molecules creates PVC resin – which is where all vinyl compounds begin. The suspension polymerization process is most widely used process to manufacture PVC. First, the raw material VCM is pressurized and liquefied, and then fed into the polymerization reactor, which contains water and suspending agents in advance. Through high-speed agitation within the reactor, small droplets of VCM are obtained. Next, the initiator for polymerization is fed into the reactor, and PVC is produced by reaction under a few bar at 40 - 60° C. PVC obtained through suspension polymerization is suspended in water as particles of 50 - 200μm diameter (in slurry form). Thereafter, the slurry discharged from the polymerization reactor is stripped of residual monomer, dehydrated, dried and the particle size controlled by screening to yield PVC in the form of a white powder. The un-reacted VCM is entirely recovered through the stripping process, and after purification, recycled as raw material for reuse in this process. PVC resin produced via this ‘suspension’ process is referred to within the industry using the abbreviation S-PVC. Emulsion polymerization and bulk polymerization are alternative, much less extensively employed, technologies to manufacture PVC. Emulsion polymerization produces finer resin grades having much smaller particles, which are required by certain applications. This type of resin is sometimes called ‘paste’ PVC and referred to within the industry using the abbreviation P-PVC to distinguish it from S-PVC. PVC comes in two basic forms: rigid (sometimes abbreviated as RPVC) and flexible. The rigid form of PVC is used in construction for pipe and in profile applications such as doors and windows. It is also used for bottles, other non-food packaging, and cards (such as bank or membership cards). It can be made softer and more flexible by the addition of plasticizers, the most widely used being phthalates. In this form, it is also used in plumbing, electrical cable insulation, imitation leather, signage, inflatable products, and many applications where it replaces rubber.   PVC Production Process in China The calcium carbide route used in China involves heating lime and coal-derived coke in an electric furnace at a temperature of 2,000 °C to obtain calcium carbide. Acetylene is generated by the hydrolysis of this calcium carbide. This early part of the process is labor intensive, requires a lot of energy, and generates vast quantities of a watery calcium hydroxide slag. With the use of a catalyst that is usually based on mercuric chloride, the acetylene is then reacted with anhydrous hydrogen chloride to produce vinyl chloride.   Major Technology Providers & Producers EDC/VCM: Ineos Technologies OxyVinyls Tosoh Vinnolit   PVC: Arkema Hanwa Chemical Ineos Technologies Nouryon Vinnolit

Discussion on Types of Air Separation Plants Introduction: From the mass production of steel to the manufacture of sophisticated micro-chips and semi-conductors by leading technology firms, air separation plants – and specifically access to the right volume and purity of oxygen and nitrogen – are critical to the successful operations of a variety of manufacturing and engineering businesses. Oxygen and nitrogen can be extracted from atmospheric air using both cryogenic and non-cryogenic air separation processes. So how can chemical engineers choose between the two processes and what does each involve? Non-cryogenic air separation is ideal for lower-volume processes where cost efficiency is key and lesser purity acceptable. Typically, purities of 85–95% oxygen purity and up to 99.999% nitrogen purity can be achievable and cost effective using a non-cryogenic process. By contrast, cryogenic air separation suits (ASU) a high-volume process where purities of around 99.5% O2 and parts per billion oxygen in nitrogen may be required, or very high-volume processes that would require many non-cryogenic air separators to achieve the required output. Ultimately, each situation is different and any approach should be tailored and bespoke to requirements, with the focus firmly on achieving the best return on investment. Process Differences: In both cryogenic and non-cryogenic processes, the air is compressed and the heat of compression is removed. Sometimes further cooling is achieved via shell-and-tube exchangers or direct contact aftercoolers using both cooling water and chilled water. Downstream of air cooling, the two methods of production differ significantly. For cryogenic plant, to ensure safety and facilitate an efficient process, it is critical that contaminants such as CO2, water vapor and heavy hydrocarbons are removed from the air. This is achieved using temperature swing adsorption (TSA). The adsorber vessels contain beds of activated alumina and molecular sieves. They operate cyclically, alternating between adsorption and regeneration, achieved with dry waste gas. Some of the lighter hydrocarbons pass through the TSA and into the cold box where their concentration is monitored and controlled. In the non-cryogenic process, hydrocarbons, moisture and particulates are removed using carbon towers, filters and mist eliminators. The process gas then enters a pressure swing adsorption twin-bed system using a carbon molecular sieve which separates oxygen and CO2 from the air. Different adsorbents attract certain gases more strongly than others. For example, in nitrogen production, oxygen is preferentially adsorbed on the bed while a nitrogen-rich stream is recovered as product. Exhaust gases are vented to atmosphere.  Other technologies such as membranes are used to produce typically 95–99.5% nitrogen in typical volumes of 25 tons per day (tpd). Vacuum swing adsorption is an alternative means of low-purity oxygen production for markets such as glass, wastewater treatment, cement production, bio-fuels, metals production, pulp and paper and steel.  The range of oxygen production varies from 5–500 tpd. Cryogenic Air Separation: Cryogenic air separation units (ASUs) then take the air through another cycle of treatment to extract gases of a higher purity of volumes in excess of 4,000 tpd per ASU. This involves air liquefaction and distillation. The boiling points of pure gases are -183°C for oxygen and -196°C for nitrogen at atmospheric pressure. By compressing the air, heat integration within the cold box is allowed and nitrogen is condensed against boiling oxygen in the low-pressure column reboiler. Cycle selection is dependent on product purity, range of products and whether gas or liquid products are required. Choosing the optimal configuration is vital to minimizing capital and operating costs. The cold box contains distillation columns operating at a range of pressures. The clean air stream is cooled in a main heat exchanger (MHE) before flowing to a high-pressure column, with a fraction of the cooled air expanded to provide refrigeration to the plant. Alternative means of refrigeration may be employed; for example, liquid nitrogen (LIN) injection. In the high-pressure column, the liquid from the bottom of the column becomes enriched with oxygen, while the vapor passing up to the top of the column steadily increases in nitrogen purity. Gaseous nitrogen product is taken from the top of the high-pressure column. The vapor at the top of the column is then fed to the low-pressure column reboiler where it is condensed. A portion of the condensed nitrogen returns to the high-pressure column as reflux, and at this point a stream of condensed nitrogen may be sent to storage as LIN product. Within the low-pressure column, oxygen is withdrawn as a liquid from the sump. It may be pumped as a liquid when high pressure gaseous oxygen is required. A low-pressure waste stream may be obtained from the column, warmed in the MHE and used for TSA regeneration. Furthermore, pure argon may be produced by withdrawing a feed stream from an optimal location and processing in a separate distillation column system. Making the Choice: Both cryogenic and non-cryogenic air separation processes have their advantages dependent on the specified volume and purity. Employing the right approach and the most appropriate cycles is critical if chemical engineers are to ensure air separation plants operate at maximum efficiency, and the highest levels of safety. While ambient processes may be simpler but sometimes less efficient than cryogenic technology, they offer more flexibility for batch processing, with short startup and shutdown times and considerably less equipment. In contrast, air separation units have multiple design options which allow the whole range of atmospheric gases to be recovered. Major Air Separation Plant Producers Cryogenic Air-Separation: Air Products and Chemicals, Enerflex Ltd., Gas Engineering LLC, Linde AG, Messer Group GmbH, Taiyo Nippon Sanso Corporation, Inc., Technex Limited, and Universal Industrial Gases. Non-cryogenic Air-Separation: Air Products and Chemicals, Generon, Kuraray Chemical, On-Site Gas Systems, Parker Hannifin, and Proton Onsite.  

Vegetable Oils & Fats: Vegetable Oils are obtained from a variety of seeds, grains and nuts. Most common types of oil-bearing seeds and nuts are Canola, Castor, Coconut, Corn (Maize), Cottonseed, Mustard, Olive, Palm, Palm-Kernel, Peanut (Groundnut), Rapeseed, Safflower, Soybean, and Sunflower. Other major specialty oils are obtained from Almond, Avocado, Cashew, Grapeseed, Jatropha, Pecan, Pine, Shea, and Walnut. Animal Oils and Fats: Animal Oils are obtained from a variety of animals. Most common types of oils and fats include Chicken-Fat (Chicken), Fish-Oil (Fish), Lard (Pigs), and Tallow (Cows). Each one of these oils and fats comes in edible and non-edible categories and multiple grades within each category. Cleaning and Drying: The plant feedstock must be cleaned so that foreign matters are removed. This applies particularly to sand/silicate and iron which may damage the preparation plant equipment. Mechanical preparation: Most of raw materials needs to be broken to reduce the particle size to ensure proper cooking and flaking. They are then heated in cooking / conditioning equipment and their moisture further controlled in addition to be softened before the next mechanical operations. After cooking, heated grits are flaked so that the oil cells are broken and the oil more readily available for further solvent extraction or mechanical pressing. Pressing: Oilseeds containing above 20 to 25% (rapeseed, sunflower seeds, cottonseeds...) are generally pressed mechanically in order to extract most or part of the oil available in the feedstock. This operation is done through full pressing for maximum oil recovery leaving up to 5 to 10% in the final cake which is marketed as such or through a low-pressure pre-pressing operation producing a cake with higher residual oil content which is then recovered in the solvent extraction plant. Dehulling: Oil extraction plants produce a solid finished product in addition to the extracted oil; this product (cake or meal) is normally used as an important component for animal feed recipes. Depending on the meal destination, its protein content often needs to be increased and its fiber content minimized. Such characteristics are generally achieved through decortication or dehulling operations that separate the outer part of the feedstock before extracting the oil. Extraction: In the solvent extractor, solids (Flakes from the flaking machines or cakes from the pre-presses) are conveyed through the equipment while a mixture of hexane and oil (miscella) is sprayed counter-current. The extractor produces therefore de-oiled solids containing solvent and miscella. De-solventization: De-oiled solids coming out of the extractor are conveyed to a dedicated equipment that completely removes the remaining solvent while preserving the meal quality: the de-solventizer. This apparatus is usually combined with additional sections for drying and cooling the meal to the required storage and market parameters. Miscella distillation: Solvent contained in the miscella is completely removed under vacuum and optimum temperature for preserving oil quality. The solvent from the distillation as well as the one removed at meal de-solventization stage are then recycled to the extractor. Solvent recovery: Since the air entering the process together with material fed to the extractor is laden with solvent when it is removed from the plant it first passes through a specially designed absorption column to limit emission to an acceptable level. Meal treatment: The extracted meal is often subject for further treatment, including grinding to obtain the required granulometry or pelletizing to reduce its volume. Oil Refining: Vegetable and Animal Oils and Fats have impurities such as Moisture, Solids (Insolubles), Gums (Lecithins), Free-Fatty Acids (FFA), Waxes, and Compounds of Sodium, Potassium, Magnesium, Calcium, and other metals. These impurities must be removed to improve the functionality of the oils. Other characteristics of oils (such as Color, odor, and taste) are also considered impurities by modern consumers. These impurities are removed in a series of steps such as degumming (to remove gums), neutralizing (to remove FFA), bleaching (to remove color), deodorizing (to remove odor and taste), and dewaxing or winterization (to remove waxes). RBD Oil: Refined Vegetable Oil is commonly called Refined, Bleached, and Deodorized (RBD) oil. As described earlier, these are the three main steps in the refining process; although additional steps are required in most cases. Chemical Refining: In Chemical Refining, Vegetable Oil is treated with caustic lye for separation of free fatty acids from oil. This is a conventional process that can be applied to all oils. A byproduct of alkali refining is soap-stock, which is used for manufacture of low-quality washing soap. Alternately, the soap-stock can be treated with acid to recover fatty acids. The waste-water from refinery requires extensive treatment. This can be avoided by alternate Physical Refining process. Physical Refining: In Physical Refining, Vegetable Oil is subject to distillation to remove free fatty acids. The alkali treatment is completely avoided. This reduces the amount of waste water and eliminates production of soap. This process is becoming more popular. Degumming: The purpose of Degumming Vegetable Oils is to remove Gums. All oils have hydratable and non-hydratable gums. a. Water Degumming: Hydratable gums are removed by treating oils with water and separating the gums. The gums can be dried to produce lecithin. b. Acid Degumming: Non-Hydratable gums are removed by treating oils with acids and separating the gums. Neutralizing: The purpose of Neutralizing Vegetable Oils is to remove Free-Fatty Acids (FFAs). Traditionally, FFAs are treated with caustic soda (NaOH). The reaction produces Soaps which are separated from the oil. Because trace amounts of soaps remain in the oil, the oil is either washed with water or treated with Silica. Some processors prefer not to perform caustic neutralizing. Instead, they prefer Physical Refining in which the FFAs are evaporated from the oil under high temperature and vacuum. This process can be combined with deodorization step described under FFA stripping. Physical Refining process is preferred because (a) it does not produce soaps; (b) it recovers fatty acids that provide better cost recovery; (c) there is smaller yield loss compared to caustic refining—especially for oils with higher FFAs; and (d) it is a chemical-free process. Bleaching: The purpose of Bleaching is to remove color pigments contained in Vegetable Oils. The oil is treated with Bleaching Clays that adsorb the color pigments. The clay is filtered and the clean bleached oil is stored for further processing. Deodorizing: The purpose of Deodorizing Vegetable Oils is to remove odor substances. The oil is subjected to steam distillation under high temperature and vacuum to evaporate all odor substances. The resulting deodorized oil is almost bland and tasteless. FFA Stripping As mentioned previously, the Deodorizing equipment can be modified to achieve Physical Refining. Since the conditions for deodorization and physical refining are almost identical, the modified equipment can be employed to achieve deodorization as well as physical refining. Fatty-Acid Recovery: Fatty-Acids are evaporated (distilled) in FFA Stripping. The Fatty-Acid vapors are condensed by direct contact with liquid Fatty-Acids to recover the evaporated Fatty-Acids. The distillation and condensation of Fatty-Acids is accomplished under very high vacuum to lower the boiling point of Fatty-Acids and prevent them from oxidizing.  Dewaxing/Winterizing: The purpose of Winterization Vegetable Oils is to remove waxes especially in those oils that contain waxes. Such oils are subjected to chilling and filtration to remove waxes and other high melting point substances. Winterizing is also used to separate the unsaturated fats from unsaturated fats—especially in Palm Oil or other saturated fats. The chilling process solidifies the saturated fats; thus enabling separation via filtration. Hydrogenation: Vegetable Oils have varying degrees of saturation levels. Some food products can only be prepared in saturated oils & fats. Hence, some food companies hydrogenate vegetable oils to produce desired level of saturation in the Oils & Fats. Vegetable oils can be hydrogenated under high temperature and pressure in the presence of a catalyst. Bakery Fat: The bakery industry uses hydrogenated oil (i.e., shortening). However, the shortening for bakery application should be of smooth texture. Granular texture, while desired in vanaspati ghee, leads to bleeding of fat in bakery products. Hence, hydrogenated oil is cooled under controlled conditions to get a product with smooth plastic texture suitable for the bakery industry. Lecithin: Gums (Lecithin) present in Vegetable Oils are valuable emulsifier and an additive in prepared foods. Hence, it may be profitable to recover them for sale to food companies. The degumming process described above produces a mixture of gums, oil, and water. The mixture of gums, oil, and water is introduced in a thin-film evaporator operating under vacuum to remove water. The resulting dry mixture of gums and oil is sold as crude dry gums or lecithin. The main design concerns are that the evaporation of water should be quick and take place under higher vacuum to prevent charring and discoloring of gums. Soap-Splitting (Acidulation): The caustic neutralization process described above produces Soap Stock—a mixture of Soaps (Fatty-Acid Salts), Oil, and Water. Soap Stock, by itself, is a low value by-product—usually a waste product. However, it contains considerable amount of Fatty Matter, which may be profitably recovered for sale as a higher-value product. This is accomplished by converting Soaps into Fatty Acids by reacting with an Acid. The resulting product is a mixture of Fatty Acids and Oil (commonly called Acid Oil). Glycerolysis: The physical refining process described above produces Fatty Acid Distillate—a mixture of Fatty Acids and Oil. The value of the Distillate may be enhanced by converting Fatty Acids into Oils through Glycerolysis. This is accomplished by reacting Fatty Acids with Glycerin to produce Oil. The resulting product is dried to recover oil for sale as a higher-value product. GMP: Good manufacturing practice also implies the following: the use of stainless steel equipment; the careful deaeration at < 100°C before heating to the final stripping temperature; the use of oxygen-free steam; and strict feedstock specifications (typically: Fe 0.1, Cu 0.01, P S, bleaching earth 5 mg/kg oil max.). Investigations in which oil was maltreated under extreme conditions determined the effects of temperature (240-300°C) and time (30-180 min.) during "physical refining" of soybean oil (degummed with phosphoric acid and lightly bleached, but still containing 20 mg P, 0.35 mg Fe and 0.05 mg Cu per kg oil). A strong effect of temperature on the formation of trans fatty acids and polymeric compounds. Time also has a significant effect. At 280-300°C, there was evidence for appreciable inter- or intra-esterification (increase in the content of saturated fatty acids at the 2-position of the triacylglycerols); substantial amounts of conjugated fatty acids were formed as well. The shaded areas indicate the usual range of processing conditions required for physical refining (270°C for 30 mins. 250°C for 1 h; 240°C for 2 h; 220°C for 3 h). Under these conditions, all changes induced by the high temperature treatment appear to be relatively minor. Major Edible Oils & Fats Equipment Manufacturers: Technochem builds esterification, trans-esterification, methanol rectification, degumming, bleaching, deodorizing, dewaxing, and oil-refining plants.  De Smet Engineers & Contractors is a major engineering and contracting firm involved in all steps of the production of vegetable oils from oilseeds crushing for the construction of Edible Oils Plants. Alfa Laval, Chempro, Silverson, and Zink Hamworthy are major edible oil process equipment manufactures, and Desmet Ballestra is a major technology provider Conclusions: Commercial refining produces fats and oils that can be of high quality and have the characteristics of bland taste, clear color, good keeping quality and frying stability. Commercially-refined fats and oils are free from known contaminants extracted from the raw agricultural products. Temperature, time and pressure must be carefully controlled during industrial refining. Oil products should be properly stored, transported and packaged to maintain quality and consumers must assume responsibility for not abusing oils and fats within households. Industry can design almost any fat or oil for a specific application by the use of various modification processes, such as hydrogenation, interesterification, fractionation or blending. Hydrogenation typically reduces essential fatty acid content and creates various fatty acid isomers, both cis and trans. The wide flexibility available to industry through the selection of raw materials and different modification processes allows for the production of oils at the lowest cost possible, an important aspect of food production.

When you want to sell your used industrial manufacturing or processing equipment, you usually are looking for fast turnaround. The quicker you can convert surplus machinery and components to cash, the sooner you can reinvest in new equipment, inventory, marketing or other business priorities. If you have researched how to sell industrial equipment quickly and efficiently, you have probably found that working with used equipment dealers is your best option. Selling to surplus industrial equipment buyers relieves you of the cost and time investment needed to: Assess your equipment’s value in an ever-changing market Develop and execute a marketing and sales strategy Run credit checks on buyers Negotiate terms Pack and ship bulky machinery Used industrial equipment dealers such as Phoenix Equipment handle decommissioning and securing equipment, freight arrangements, and more, putting cash in your hand in days, not months or years. When you sell industrial equipment to surplus machinery buyers, you keep your production and operations disruption to a minimum. How to Get Maximum Profit on Industrial & Chemical Equipment Just because you need cash fast doesn’t mean you have to settle for pennies on the dollar when you sell industrial equipment. At Phoenix, we pride ourselves on offering sellers fair market value for their unwanted equipment. Making sure to provide complete, accurate information on the machinery you have for sale allows us to offer quick and accurate quotes. In fact, by taking a few simple steps, you can ensure Phoenix Equipment’s expert estimators can offer you top dollar on your manufacturing and processing equipment. When you want Phoenix to prepare a bid on your industrial equipment – whether it’s a single machine or an entire production line or plant – be sure to give us as much information as possible including: Equipment List – Start with a complete, itemized list of the equipment you have for sale. Include quantities of each intact component or machine and all spare parts. Specifications – Enter equipment on separate spec sheets that include details about the machinery’s current use, capacity, manufacturer, model and serial number, etc. Whatever data you would consider when buying processing equipment is important to include so Phoenix Equipment and our potential buyers can form a full picture and understand different ways the equipment could be employed. Condition – Give us an honest description of the equipment’s appearance and functionality. Make a note of any parts that are missing, broken, or show signs of extensive wear. Your forthrightness will establish your reputation as an ethical seller, which will pay off in the long run. To make it easier to establish condition, you could upload the equipment’s maintenance records, owner manual, and dates key parts were replaced. Like any buyer, understanding the equipment’s condition will allow us to accurately price and purchase the equipment. Location – Let us know where the equipment is physically located. This will help us determine how difficult it will be for us to secure it and ship it to Phoenix Equipment’s facilities for refurbishing and preparation for resale. The more accessible the equipment, the easier the logistics, the less we have to spend on strapping and shipping, allowing us to put more money in your pocket. Images and Video –A picture is worth 1,000 words and videos are worth even more. Including well-lit, high-resolution images with your equipment details is crucial. Send several shots of each machine: establishing shots of the equipment in situ on the plant floor; closeups of major components and their interfaces with each other; shots of electrical controls, monitors, and gauges; photos of safety features, moving parts, and features behind doors and panels. Videos can demonstrate that equipment remains in good working order and makes a strong impression. When you’re ready to sell your industrial processing and manufacturing equipment quickly and for top dollar, visit our submissions page and send us as much information as you can.

Older chemical processing plants often have a lot more to give. They may be decommissioned for a variety of reasons, and relocating the equipment to overcome those circumstances could prove economical for companies looking to save money. Moving chemical and processing plants across regions, or even oceans can provide several major benefits including: Proximity to greater demand Access to cheaper workforces or raw materials Expanded operations Escape from stringent industrial regulations Money savings compared to purchasing new equipment Time savings on engineering, specifications, production design, and documentation While the cost of purchasing an existing plant, dismantling and refurbishing the equipment, shipping it to a new location, and reassembling can seem like an impossible task, in many cases it can be significantly lower than purchasing new components and building a brand new plant. Once the decision to relocate has been made, extensive, detailed planning and an agreement with experienced professionals can make even the most complicated manufacturing facility move manageable and efficient.   Properly Document the Decommissioning and Disasssembly Properly deactivating the process equipment at its existing location will ensure efficient set up at the other end. Start by documenting the location, orientation, configuration and relationship between the components in site. Photographs, diagrams, match-marking, and color-coded tags can be useful when the processing plant is reassembled in its new location. More than simply a map for the reassembly team to follow, these schematics and visual representations should also note the placement of vertical features – overhead conveyors, maintenance corridors, pits, trenches, etc. Do not rely on old documents. Where layout drawings exist, check their accuracy by conducting walking equipment inspections. Where they do not exist, take special care to create them. If the plant is operational prior to relocation, benchmark, and calibrate machine performance before shutting it down.   Process Equipment Review Equipment walk-through inspections also will allow experts to assess the quality and condition of each component. It is probable that not all machinery will be in optimal working order. Some may have to be repaired, overhauled or refurbished, while other parts can require replacement. A partner experienced in buying and selling chemical plants and equipment can appraise each machine and offer guidance on whether specific processing equipment is worth salvaging. While relocating a production plant can help save money on equipment, not all components will be worth reusing. When repairs, freight charges, storage costs, lost scrap value, etc. are considered, sourcing replacement equipment near the new plant location may be more economical than relocating some pieces. Make this determination early in the process. This not only saves time and freight costs, it also allows companies to locate and purchase replacement equipment so it is on hand when it comes time to reassemble the line in the new location.   Shipping The actual relocation of a production plant involves much more that crating equipment and putting it on a ship or rail car. A comprehensive plan will ensure the receiving location is prepared in time for the donor plant’s arrival. A plant relocation expert will schedule the timing of each component’s arrival so the team on the receiving end can have the necessary platforms, bases, utility connections, and other structures in place. The relocation partner should offer custom rigging and packaging that provides the greatest damage protection for condensers, vessels, compressors, converters, and other valuable equipment. They should organize ground shipments on high-capacity trailers and flatbed railcars that eliminate cargo shifts and cushion the ride. For overseas transport, you should expect your partner to coordinate with shipping firms and handle logistical challenges, documentation, export paperwork, and scheduling to deliver your plant components swiftly and undamaged.   Reassembly and Commissioning Your relocation contractor should use match marking, equipment tags, and the schematic and photographs created before the plant was dismantled to bring the “new” plant online safely and efficiently. A comprehensive reassembly program begins even before the plant equipment arrives from its original location. The plant engineer and/or relocation vendor should fully prepare the new site, installing anchors, skids, platforms, and other equipment bases. Then, using the match-marks and photographic documentation created before dismantling, the team can reassemble production lines, storage tanks, subassemblies, etc., including electrical connections and mechanical applications. When the plant equipment is connected to electricity, gas, water, and other utilities, the contractor and plant engineer then can conduct tests to ensure all connections are complete and functional.   Trust Phoenix for Plant Relocation As mentioned earlier, there are many reasons to consider relocating your process facility, whether it be nitrogen fertilizer plants (ammonia, urea, nitric acid, ammonium nitrate), methanol and syngas plants or any other type of plant. Whatever your reasons, Phoenix Equipment will help you succeed. Put our industry expertise and comprehensive services to work, guiding your company through the entire process. Contact Phoenix today to learn more about our plant relocation services.

The urea production uses CO2 gas and liquid ammonia as raw materials supplied from an Ammonia plant. This article will divide urea production into six sections: 1) Synthesis & HP Recovery; 2) MP Purification & Recovery; 3) LP Purification & Recovery, 4) Vacuum Concentration; 5) Condensate treatment; and 6) Prilling.   SYNTHESIS AND HIGH PRESSURE (HP) RECOVERY In addition to the HP machinery required to feed ammonia and carbon dioxide and to recycle ammonium carbamate solution, this section includes: the reactor where urea is formed; the stripper necessary to strip out as vapors, from the urea solution leaving the reactor, a large amount of ammonia and carbon dioxide not converted to urea in the reactor; the carbamate condenser that condenses these vapors; the ejector that recycles the ammonium carbamate solution to the reactor. In this equipment the pressures are of a similar level, 150 bar, while the temperatures of the outlet solutions are 188, 205 and 155°C for the reactor, the stripper and the carbamate condenser, respectively. Inside the reactor a matching number of trays of a very simple design are installed to improve the conversion. Under these conditions 62-64% (conversion) of the total CO2 entering the reactor is converted to urea. The total carbon dioxide conversion in the HP section (or loop) is 85-90%. All the equipment in this section, the heaviest of the urea plant, is installed at ground level, thus providing a horizontal layout with all the relevant benefits. The stripper and the hydrolyzer in the waste water section are the only two items of equipment in the plant that consume medium pressure steam. The amount of steam consumed in the stripper is practically completely recovered in the carbamate condenser: its pressure is lower but still sufficient to be used in the urea plant itself. The quantity of oxygen introduced into the plant as air is 0.25% vol of the fresh feeding carbon dioxide. This minimum amount guarantees, at the same time, excellent equipment passivation and the absence of explosive mixtures where the “inerts” are released from the plant into the atmosphere after practically all the ammonia contained therein has been washed. Thanks to the proper choice of the materials in contact with the process fluids and to the presence of excess ammonia, it is possible, during unscheduled shutdowns lasting only a few days, to bottle-in the high-pressure synthesis loop by operating a few valves, thus keeping all the process solutions inside the loop. In this way obvious pollution and start-up problems are completely averted. All kinds of machinery (reciprocating and centrifugal) is utilized according to local conditions.   MEDIUM PRESSURE (MP) PURIFICATION AND RECOVERY The purpose of this section is to partially strip out the reactants, ammonia and carbon dioxide from the urea solution and, after their condensation in water, to recycle the obtained solution to the reactor, together with the ammonia and carbon dioxide aqueous solution resulting from the downstream sections of the plant. The ammonia excess is separated in this section and recycled to the reactor separately. A distillation column is provided for this purpose. The operating pressure is 17 bar g. A particular feature is included in this section. Ammonia and carbon dioxide are partially condensed in the shell of a preheater within the vacuum section, thus recovering some energy in the form of 200 kg of steam per ton of urea, with an investment cost that, even in existing plants, has a pay-back time of less than two years. Another particular characteristic of the MP section is the washing of the so-called inerts (CO, H2 and CH4 contained mainly in the carbon dioxide and the passivation air). For the complete abatement of the ammonia contained in the inerts, in completely safe conditions with regard to explosions, The inerts are washed with water after the addition of a quantity of flammable gas, as for example natural gas, in such an amount that after the ammonia has been eliminated, the composition of the inerts is out of the explosive field due to the excess of flammable gas. The washed inerts are sent to a burner together with the natural gas. It should be emphasized that the presence of the MP section provides great plant flexibility, which can be operated over a wide range of NH3/CO2 ratios, with excess ammonia present in the urea stream from the stripper being recovered and condensed by the MP section.   LOW PRESSURE (LP) PURIFICATION AND RECOVERY Further stripping of ammonia and carbon dioxide is made in the LP section, operating at 3.5 bar g. The vapors, containing ammonia and carbon dioxide, are condensed and recycled to the reactor via the MP section. An appropriately sized tank is provided in this section to collect all the solutions from the plant when it is shut down for long time. Therefore, in no circumstances are solutions discharged from the plant.   VACUUM CONCENTRATION The urea solution leaving the LP section is about 70% b.w. and contains small quantities of ammonia and carbon dioxide. The final concentration of the urea solution (99.8% b.w.) is made under vacuum in two steps at 0.3 and 0.03 bar abs. for the prilled product, and in one or two steps for the granular product, according to the granulation technology chosen. An important feature of this section is the preconcentration of the urea solution to about 86% b.w. The necessary heat is provided by partial condensation of the vapors (ammonia and carbon dioxide essentially) from the MP section evaporator. A simple solution has been found to the problem of lump formation in the second vacuum separator: lump formation is prevented by wetting the internal walls of the separator by means of a small recycle of molten urea.   PROCESS CONDENSATE TREATMENT This stage discharges a large amount of process water with 1 ppm of urea and 1 ppm of ammonia lowers specific consumption of ammonia and reutilizes process water as boiler feedwater). All possible and convenient heat recoveries are generally introduced into this section in order to minimize energy consumption.   FINISHING: PRILLING Prilling is the easiest technology to manufacture solid urea with commercially valid chemical and physical characteristics. Molten urea (99.8% b.w.) is sprayed at the top of the prilling tower, at a height of 55-80 m, according to climatic conditions; at the bottom, essentially spheroidal urea particles, namely prills, are collected and sufficiently cooled in order to be sent to storage or directly to the bagging section without screening, coating or any other treatment. A rising draught of air inside the prilling tower is the cooling medium that removes the solidification heat and cools the prills.   MAJOR TECHNOLOGY LICENSORS There are multiple technology licensors with proprietary plant designs and features. The main urea process licensors are Snamprogetti, Urea Casale, Kellogg and Stamicarbon.   COST AND UTILITIES OF AN UREA PLANT A new plant constructed in Azerbaijan in 2018 by Samsung Engineering, with licensing in place with Haldor Topsoe for the production of ammonia and Stambicarbon for the production of urea, produces 1,200 tons of ammonia and, subsequently, 2,000 tons of urea per day. The plant will consume 25-26 MW of electricity per hour. The urea plant will require 1.3 million cubic meters of natural gas per day for operation at full capacity. The cost of the project is 770-780 million euros.

Competition between Ammonia technology suppliers is quite fierce. Three technology licensors — KBR (Kellogg Brown and Root), Haldor Topsøe, and ThyssenKrupp Industrial Solutions (TKIS) — currently dominate the market. Ammonia Casale, which offers an axial-radial catalyst bed design, is a market leader in revamps of existing plants. Most of the ammonia plants recently designed by KBR utilize its Purifier process, which combines low-severity reforming in the primary reformer, a liquid N2 wash purifier downstream of the methanator to remove impurities and adjust the H2:N2 ratio, a proprietary waste-heat boiler design, a unitized chiller, and a horizontal ammonia synthesis converter. Depending on the configuration of the plant, energy consumption can be as low as 28 GJ/m.t. Because the secondary reformer uses excess air, the primary reformer can be smaller than in conventional designs. The cryogenic purifier, which consists of an expander, condenser, feed/effluent exchanger, and rectifier column, removes impurities such as CO, CH4, and argon from the synthesis gas while adjusting the H2:N2 ratio of the makeup gas in the ammonia loop to the optimum level. The ammonia concentration exiting the low-pressure-drop horizontal converter is 20–21%, which reduces energy requirements for the recycle compressor. The syngas generation section (or front end) of a Haldor Topsøe-designed plant is quite traditional with the exception of its proprietary side-fired reformer, which uses radiant burners to supply heat for the reforming reaction. Haldor Topsøe also offers a proprietary iron-based synthesis catalyst, radial-flow converters consisting of one, two, or three beds, and a proprietary bayonet-tube waste-heat boiler. More recent developments include the S-300 and S-350 converter designs. The S-300 converter is a three-bed radial-flow configuration with internal heat exchangers, while the S-350 design combines an S-300 converter with an S-50 single-bed design with waste-heat recovery between converters to maximize ammonia conversion. ThyssenKrupp offers a conventional plant with a unique secondary reformer design, a proprietary waste-heat boiler, radial-flow converters, and a dual-pressure ammonia synthesis loop. Today, a production rate of 3,300 m.t./day can be achieved using the TKIS dual-pressure process. ThyssenKrupp’s dual-pressure synthesis loop design features a once-through reactor between syngas compressors. The Linde Ammonia Concept (LAC) is an established technology process scheme with over 25 years of operating experience in plants with capacities from 200 m.t./day to over 1,750 m.t./day. The LAC process scheme replaces the costly and complex front end of a conventional ammonia plant with two well-proven, reliable process units: a) production of ultra-high-purity hydrogen from a steam-methane reformer with PSA purification; b) production of ultra-high-purity nitrogen by a cryogenic nitrogen generation unit, also known as an air separation unit (ASU). Also featured is a pressure-swing adsorption unit for high-purity hydrogen production and an air separation unit for high-purity nitrogen production. Ammonia Casale’s plant design has a production rate of 2,000 m.t./day. One of the key features of this design is axial-radial technology in the catalyst bed. In an axial-radial catalyst bed, most of the synthesis gas passes through the catalyst bed in a radial direction, creating a very low pressure drop. The rest of the gas passes down through a top layer of catalyst in an axial direction, eliminating the need for a top cover on the catalyst bed. Casale’s axial-radial catalyst bed technology is used in both high-temperature and low-temperature shift converters, as well as in the synthesis converter. Ammonia Casale’s process employs a catalyst bed that harnesses axial-radial technology, which has a lower pressure drop and higher efficiency than standard catalyst beds. Ammonia from coal The basic processing units in a coal-based ammonia plant are the ASU for the separation of O2 and N2 from air, the gasifier, the sour gas shift (SGS) unit, the acid gas removal unit (AGRU), and the ammonia synthesis unit. Oxygen from the ASU is fed to the gasifier to convert coal into synthesis gas (H2, CO, CO2) and CH4. There are many gasifier designs, but most modern gasifiers are based on fluidized beds that operate above atmospheric pressure and have the ability to utilize different coal feeds. Depending on the design, CO levels of 30–60% by volume may be produced. After gasification, any particulate matter in the synthesis gas is removed and steam is added to the SGS unit. The SGS process typically utilizes a cobalt and molybdenum (CoMo) catalyst specially designed for operation in a sulfur environment. After reducing the CO concentration in the synthesis gas to less than 1 vol%, the syngas is fed to an AGRU, where a chilled methanol scrubbing solution (e.g., Rectisol) removes CO2 and sulfur from the synthesis gas. The CO2 overhead is either vented or fed to a urea plant. The sulfur outlet stream is fed to a sulfur recover unit (SRU). Syngas that passes through the AGRU is typically purified by one of two methods: a) a nitrogen wash unit to remove residual CO and CH4 from the syngas before it is fed to the synthesis loop; b) a PSA system for CO and CH4 removal. Cost of Ammonia Plants There have been several recent cases of greenfield new ammonia plants that have taken 36 to 48 months for mechanical completion and have cost in the billions. While full cost reports are not in, the expected final costs are in the $1,500 to $2,200 per annualized ton range (Total capital cost divided by the expected total annual tons). A recent used plant for relocation project was a 1,000 ton per day Kellogg Design that was removed, relocated, rebuilt and upgraded. This project was in the range of $500 million and took 25 months to mechanically complete from the groundbreaking (after an environmental permit was issued). The ground breaking occurred in December 2013 and the first drop of ammonia was in April 2016. The full costs were less than $1,100 per annualized ton.

INTRODUCTION TO PET PRODUCTION PET may be produced from ethylene glycol and either dimethyl terephthalate (DMT) or terephthalic acid. High purity is required of all raw materials. In either case, the first step of the reaction is the formation of a prepolymer, bis-hydroxyethyl terephthalate (bis-HET). Subsequent polymerization of this material (with the removal of ethylene glycol) forms the polymeric polyethylene terephthalate. The extent of polymerization (apparent from the molecular weight of the polymer) is a function of the polymerization conditions and significantly affects the properties of the resin that is produced. Until the mid-1960s, DMT had been the preferred feedstock for PET manufacture, partly because the ester could generally be made in purer form than the acid. With the development of high-purity terephthalic acid processes, notably by Amoco, the free acid gained acceptance and is now the preferred feedstock. The use of high purity terephthalic acid (purified terephthalic acid - PTA) eliminates the need to recover or recycle methanol and has the added advantage that esterification to the prepolymer is considerably more rapid than the transesterification reaction, which is the first step when starting from DMT. The conventional PET process consists of two discrete plant sections; the melt phase reaction to lower intrinsic viscosity product that is suitable for textile applications, but not for bottle grade and other high molecular weight applications. That lower intrinsic viscosity material is then further polymerized to bottle-grade intrinsic viscosity in a solid-state polymerization section. Note that intrinsic viscosity (as well as molecular weight) indicates the degree of polymerization, which in turn is the main factor in setting the properties of PET. COMMERCIAL ANALYSIS Fiber producers have for some time been converting older plants to PET bottle grade production by adding SSP capacity, in order to escape the more difficult market conditions in the fibers industry. This is still ongoing in certain areas, although the amount of remaining capacity that could be converted to competitive PET resin capacity is minimal relative to the amount of new capacity expected. RESOURCE LINKS Phoenix Equipment sells used PET and PTA plants that are immediately available for purchase and relocation. Buying a used plant can save you significant capital and drastically shorten the time required to build or expand manufacturing operations.

Oleochemical Process Plants: Fatty Acid Production and Glycerin Production The oleochemical manufacturing industry includes the processing of natural oils and fats, both of vegetable and animal origin, into numerous substances, such as: Fatty acids by cleavage (splitting) of the triglycerides molecule into its constituents (i.e. fatty acids and glycerin); Biodiesel, mainly by substitution (transesterification of glycerin with methanol in the triglycerides molecule); and Glycerin by processing glyceric aqueous solutions mainly derived from transesterification and splitting. This article will focus on the production of fatty acids, glycerin (which is a co-product of fatty acid production) and their derivatives. Fatty Acids and their chemical derivatives have a place in almost every aspect of modern living. They are used in shampoos, liquid detergents, fabric softeners, lotions, flavors, fragrances and much more. Fatty Acid Process Plants and Glycerin Process Plants supply a wide range of industrial applications with thousands of end-products mainly in the following fields: Coating & Paints Cosmetics Emulsifiers Lubricants Plasticizers Rubber Chemicals Soap & Detergents Surfactants Textile Chemicals Raw materials for fatty acid plants include soybean oil, palm oil, sunflower see oil, rapeseed oil, cotton oil, olive oil – all vegetable based oils; and animals fats like lard, butter, tallow, fish oil and poultry fat. Feedstocks are typically vary by geography and are determined by local supply and costs. Note: Crude glycerin is typically produced in an oleochemical fatty acid production plant, where fats and/or vegetable oil molecules are split to make fatty acid and a glycerin co-product at a 10:1 ratio. As noted earlier, it is also possible to make glycerin by saponification or in bio-diesel production via transesterification. Whatever the final derivate (ester, salt, alcohol, sulphate, sulphonate, amine, amide, etc.) the intermediate steps always involve the products of fatty acids, as a distilled mixture or as pure fraction: An oleochemical processing facility – aka fatty acid plant and glycerin plant - can be composed of the following processes or sections: Pretreatment Splitting Straight Distillation Heating Systems Fractional Distillation Sweetwater Treatment and Concentration Wet Fractionation Hydrogenation Flaking Glycerin Distillation and Refining Glycerin Recovery   Technology Suppliers: Below is a list of worldwide fatty acid process plant and glycerin process plant technology companies: Andreotti Impianti Desmet Ballestra DVC Process Technologists Fenix Process Technologies Gianazza JJ-Lurgi Lipico Technologies Mectech Process Engineers Muez-Hest Planning to start or expand a fatty acid or glycerin plant? Phoenix Equipment buys and sells complete fatty acid plants, glycerin plants and oleochemical facilities. Take a look at our current fatty acid plant inventory and glycerin plant inventory, or if you can’t find what you need, contact us today and one of our team members can assist you in finding exactly what you need.

The manufacturing of nitric acid for use in fertilizers, plastics, dyes, textiles, and other industrial products, has evolved to three industry-standard processes. They all produce acid with 60-68% concentration, and each uses essentially the same nitric acid plant design. The choice between medium- and high-pressure mono and dual-pressure production process often comes down to financial considerations and owner priorities. Nitric Acid Production Technology While nitric acid plant technology has made production more efficient and environmental controls more effective, the process remains the same: Ammonia combustion in the presence of hot air and a platinum/rhodium catalyst creates nitric oxide (NO). Oxidation of the NO creates nitrogen dioxide (NO2). The NO is cooled and compressed as it travels to the absorption tower. The cooling process creates nitrogen dioxide and produces heat, which is recycled for use in other plant operations. Absorption of the NO2 in water creates nitric acid (HNO3). This dilute solution dissolves in the remaining water. The reaction also forms small quantities of NO, which combine with ambient oxygen to reform NO2 and continue the reaction. Modern nitric acid plants are designed to carry out the three chemical processes in a variety of ways, considering initial investment costs, space constraints, feedstock cost, and other factors. The oxidation reaction is more efficient under medium pressure, while the absorption and ultimate production of nitric acid solution works better under high pressure. As a result, three distinct processes have been developed for carrying out the various reactions.   1. Mono Medium Pressure Process Using an uncooled radial compressor to deliver air at 4 to 5 bar abs or an axial flow compressor (5 to 6 bar abs) a nitric acid plant can produce up to 700 tons of nitric acid per day (maximum 65 percent concentration) using a single ammonia combustion unit and a single absorption tower. Production can be increased to 1,000 tons per day with the addition of a second absorption tower. Because the oxidation of nitric oxide into nitrogen dioxide occurs more quickly at lower temperatures, nitric acid plants using mono medium are more efficient than their high-pressure counterparts at this portion of the production process. And because the reaction is exothermic, the mono-medium setup’s ability to maximize energy recovery helps offset operating costs. The compressor can be driven by reusing steam captured during nitric acid production. Or, if steam can be exported for credits, the compressor can be driven by electric motor so all generated steam can be collected for export. 2. Mono High Pressure Process While medium-pressure nitric acid plants optimize the second critical chemical reaction, raising the pressure to 8 to 12 bars enhances the final step. The higher pressure “forces” the nitrogen dioxide (and dinitrogen tetraoxide, which is also produced in the oxidation phase) gas into water. Manufacturers seeking a quick capital often take advantage of this nitric acid plant technology, as a single absorption tower is sufficient to produce up to 1,000 tons of nitric acid per day. The higher pressure also means the burner unit, piping, and other equipment can be made smaller so the plant occupies a more compact footprint, making the initial capital investment less and the road to profitability shorter. 3. Dual Pressure Process As might be surmised, the dual pressure process uses two different pressures during nitric acid production. It uses medium pressure for the compressed air used in ammonia combustion, then compresses to high pressure to optimize absorption. An attempt to capitalize on the best of both mono processes, the dual pressure process can realize up to 1,500 tons per day of nitric acid (up to 70% or higher concentration) with one ammonia combustion and process gas cooler unit installed. Additional units can be added to increase capacity. The lower oxidation pressure also takes less of a toll on the catalyst – a major savings, considering the cost of platinum. Varying the pressure not only extends catalyst life, but also keeps the nitric acid concentration low as it exits the condenser, fostering its absorption into water. Which is the Best Nitric Acid Production Process? All three processes have their place in nitric acid plant design, depending on strategic goals and other factors. Initial investment in medium- and high-pressure mono process plants are generally lower than those required for dual-pressure facilities. Variable costs, however, can run higher, requiring slightly larger quantities of ammonia and taking a greater toll on the catalyst. As a result, mono –pressure nitric acid technology is more prevalent in smaller (900 tons per day and less) plants. Most experts consider the dual-pressure process the best available technology, and most new high-capacity nitric acid plants are designed for dual pressure. Because both technologies are incorporated, a higher initial investment is required, but the greater capacity and lower operating costs help recoup the investment more quickly. Typical Consumption Figures of Modern Nitric Acid Plants The following chart is the comparison of typical consumption figures for steam turbine driven and inline compressor set nitric acid plants, per ton of nitric acid (100%), with NOx content in the tail gas of less than 50 ppm. Plant Type Medium Pressure Process High Pressure Process Dual Pressure Process Operating Pressure (abs.) 5.8 bar 10.0 bar 4.6 / 12.0 bar Ammonia 284 kg 286 kg 282 kg Electricity 9.0 KWH 13.0 KWH 8.5 KWH Platinum, Primary Losses 0.15 g 0.26 g 0.13 g Platinum losses after recovery 0.04 g 0.08 g 0.03 g Cooling water (Δt = 10 k), including water for steam turbine condenser 100 t 130 t 105 t Process Water 0.3 t 0.3 t 0.3 t LP heating steam, 8 bar, saturated 0.05 t 0.20 t 0.05 t HP excess steam, 40 bar, 450 ºC 0.76 t 0.55 t 0.65 t Energy Recovery and Tail Gas Treatment Whichever technology a nitric acid plant uses, each reaction in the production process releases energy, which can be recovered and used throughout the plant. For instance, the air used to oxidize the ammonia must be filtered, compressed and heated. It is possible to obtain nearly all the energy required for these processes by extracting heat from tail gasses. Nitric acid plants must treat the NO, N2O, and NO2 gasses produced throughout the manufacturing process. Both are greenhouse gasses and can do great harm to the environment if not properly neutralized. A variety of technologies exist to make these waste gasses less harmful including: Heating them in the presence of a catalyst to convert NOx to nitrogen Installing additional absorption trays (or a complete additional absorption tower) Cooling weak acid within the absorption tower Attaching molecular sieves to contact tail gasses to return NO for another pass through the absorber Use of liquid alkali, carbonates, or potassium permanganate (wet scrubbers) to pull NO from tail gas to form nitrate salts Leading Technology Licensors Weatherly, a company of Chematur Engineering Group of Sweden; ESPINDESA, a company of Técnicas Reunidas of Spain; Borealis of Austria; Uhde (now ThyssenKrupp Industrial Solutions) of Germany; MECS Technology of USA; KBR of USA; Technip of France. Planning to start or expand a nitric acid plant? Phoenix Equipment buys and sells complete nitric acid plants. Take a look at our current nitric acid plant inventory or if you can’t find what you need, contact us today and one of our plant experts can assist you in finding exactly what you need, no matter which nitric acid production process you are looking for.

Understanding the molecular process of methanol applications has provided us with the opportunity to create practical solutions for its use. Beneficial products such as antifreeze, wastewater treatment, camping and boating stoves, de-staining products, and even acetic acid are all produced using methanol. Among its most prominent applications, methanol has been used to fuel ground transportation vehicles through its production of methyl tert-butyl ether (MTBE), which is most commonly applied as an octane booster in gasoline. Methanol can also be used to produce biodiesel as well as diesel and gasoline for high performance engines. Looking to the future, researchers are studying methanol’s potential for sustainable energy use because of its short half life in groundwater. Whereas benzene can carry a half life of up to 730 days, methanol is considerably biodegradable with a half life of up to only 7 days. Some suggest that there may even be a use for methanol in powering electronic devices such as laptops and cell phones. No matter the intended use of the methanol, there are three distinct stages of methanol production, including: 1. Autothermal Reforming of Natural Gas to Synthesis Gas While methanol can be made from biomass, carbon dioxide plant emissions, and most fossil fuels, natural gas is the by far the most widely used feedstock for its convenience and efficient conversion. The first step in methanol production requires the formation of synthesis gas (“syngas” is a mixture of hydrogen and carbon monoxide gases) from natural gas. Natural gas and steam in a 3:1 ratio are heated to 1,300 to 1,800 degrees Fahrenheit inside nickel catalyst-filled tubes. Methane, natural gas’s primary component, reacts with the water vapor to make syngas: CH4 + H2O à3H2 + CO The exact ratio of hydrogen and carbon monoxide in the product can be controlled through pressure, natural gas composition, steam-to-carbon ratio, and other reactor design and processing variables. The steam methane conversion equation above produces a 2:1 diatomic hydrogen to carbon monoxide ratio. This autothermal reforming of natural gas ratio is perfect for producing both fuel-grade and high-purity methanol outlined in step 2. 2. Methanol Synthesis When exposed to a copper/zinc oxide, aluminum oxide catalyst, single carbon monoxide molecules combine with two diatomic hydrogens to synthesize methanol: CO + 2H2 à CH3OH Any carbon dioxide in the gas mix also reacts with hydrogen for additional methanol production: CO2 + 3H2 à CH3OH + H2O These reactions take place in a low-pressure synthesis loop reactor that allows for maximum recovery of the heat generated, as the three reactions are net exothermic. Use of isothermal reactors also allows for smaller sizes to keep investment and operating costs down. Composition of the catalyst is key, as high-performance and methanol synthesis selectivity are necessary for efficient conversion and long-term operation. The two reactions are net exothermic, and the heat generated can be converted to high-pressure steam for use in other operations in the plant or to generate electricity. Many methanol plants have installed pre-reformers that optimize the natural gas feed for more complete syngas production. The adiabatic conversion transforms higher hydrocarbons in the feed into methane and other lighter compounds such as carbon oxides and hydrogen so the primary reformers can work more efficiently. After treatment by the pre-reformers, the syngas enters a stand-alone, oxygen-fired autothermal reformer composed of a: Burner Combustion zone Catalyst bed in a refractory lined pressure vessel As the burner combusts, the feedstock in the oxygen-rich environment to complete the steam reforming and shift conversion reactions to equilibrium. The synthesis gas produced by ATR is rich in carbon monoxide, resulting in high reactivity of the gas. Removing carbon dioxide or recovering and recycling hydrogen makes it suitable for methanol production. 3. Methanol Purification and Distillation Synthesized methanol and water travel to a two-stage separation and boiler tower for purification and distillation to concentrations of 99.85% by weight or even greater. The product flowing into the vaporizing units typically contains 18% water, as well as alkanes, alcohols and propanol that must be burned off to achieve the required purity (IMPCA or U.S. Grade AA). Topping – First-stage purification is a topping process that removes “light end” impurities with relatively low boiling points. The water/crude methanol mixture is heating in the topping column to a temperature below methanol’s boiling point. “Light end” pounds boil off. Refining – In the second stage, the methanol/water mixture enters a refining column consisting of series of boiling tanks. Methanol boils at a lower temperature than water, so as the first tank is boiled, methanol vapor rises (along with some water steam) into the next tank. The vapor is cooled, then boiled again in each tank. Every iteration of boiling/cooling process extracts the methanol and lesser and lesser quantities of water until the liquid methanol concentration approaches 100%. Phoenix Equipment sells second-hand methanol synthesis loop equipment and turnkey plants immediately available for relocation. Buying used plants and components can save manufacturers significant capital and drastically shorten the time required to build or expand manufacturing operations. Contact us today so we can help you find the processing equipment or plant to suite your needs.

Phoenix Equipment has several liquid phase oxidation units for removing H2S from Gas Streams. Below is a link to our refinery units where you can find several oxidation processes and other refinery units as well as a well-written piece by Gary Nagl called, “The State of Liquid Redox”. Phoenix Equipment Corporation Refinery Units for Sale   The State of Liquid Redox – By Gary J. Nagl Abstract As early as the beginning of the century, work has been ongoing to develop a liquid phase, regenerative process for converting hydrogen sulfide (H2S) into pure, elemental sulfur. This work has lead to the introduction of over 25 different processes, most of which with very little commercial success. However, in the late 1940’s, the North Western Gas Board and the Clayton Aniline Company developed the Stretford Process, which utilized an aqueous solution of vanadium and anthraquinone (ADA). Although the Stretford process had some serious process, operational and environmental problems, the process filled a much-needed niche and became fairly popular throughout the 50’s, 60’s and 70’s. In the late 1960’s the CIP process, which employed an aqueous solution of chelated iron, was introduced in the United Kingdom. The process failed miserably; however, its failure did lead to the successful introduction of the LO-CAT® Process in the late 1970’s, which solved many of the problems encountered with the CIP Process and the Stretford Process. In the late 1980’s, another chelated iron process, the Sulferox Process, was introduced; however, the developers of the LO-CAT and Sulferox processes have recently combined efforts to improve liquid redox processing even further. Throughout the last half of the century, liquid phase oxidation has played an important role in the recovery of sulfur from various sources of hydrogen sulfide. Of all the processes available for converting H2S to sulfur, current liquid phase oxidation systems are the most versatile. They are able to treat any type of gas stream containing H2S, at a wide variety of operating conditions and all at removal efficiencies exceeding 99%. This paper will discuss the major liquid oxidation processes, describing in detail their advantages and disadvantages. In addition, the current R&D efforts in the field of liquid phase oxidation will be discussed with a glance of what future developments may occur. Keywords: Desulfurization, sulfur recovery, liquid redox, chelated iron, LO-CAT   Introduction Liquid phase oxidation processes for the removal of hydrogen sulfide (H2S) from gas streams were initially developed to correct certain problems associated with dry oxidation processes such as iron sponge. The problems being mainly large plot requirements, replacement of the oxidation media on a frequent basis, and safety problems. This development work led to the utilization of various oxygen carriers dissolved or suspended in a liquid phase, which could be regenerated continuously at ambient temperatures. Most early development work was done for systems processing coal gas or town gas with the objective of removing both hydrogen sulfide and ammonia by the formation of ammonium sulfate and elemental sulfur. Some of these early processes included the Feld Process, the Gluud Process, and the Koppers C.A.S. Process all of which employed polythionate solutions. Because of the complex chemistry, none of these processes achieved any commercial success. After the failure of the polythionate processes, development shifted towards utilizing suspensions of iron oxide in aqueous solutions, which in essence was an attempt at a continuous iron sponge process. The hydrogen sulfide reacts with an alkaline compound to form hydrosulfide, which reacts with iron oxide to form iron sulfide, which in turn reacts with oxygen to form iron oxide and sulfur. Development work in this area lead to the introduction of the Burkheiser, Ferrox and Manchester processes. During the 1920’s the Thylox and Giammarco-Vetrocoke processes met with some commercial success. However, both of these processes employed thioarsenate solutions, which resulted in toxicity problems caused by the arsenic. Another group of processes which showed technical promise but were limited by toxicity problems were those employing iron cyanide solutions. The Fischer Process and the Autopurification process are examples. These processes employed ferric and ferrocyanide complexes as oxidizing agents. A summary of the various liquid phase oxidation processes, which have been developed throughout the years, is contained in Table I.   The Stretford Process The first liquid phase, oxidation process, which gained widespread commercial acceptance, was the Stretford process. The process was developed by the North Western Gas Board and the Clayton Aniline Company in England to remove H2S from town gas. The original process utilized an aqueous solution of carbonate/bicarbonate and anthraquinone disulfonic acid (ADA). However, the process suffered from several inherent problems. The solution had a very low capacity for dissolved sulfides resulting in large liquid circulation rates and hence, high power consumption. In addition, the sulfur formation reaction was very slow requiring large liquid inventories and resulting in high byproduct formation (thiosulfates). These problems were corrected to a certain extent by the addition of alkali vanadates to the solution, which, in essence, replaced dissolved oxygen as the oxidant in the conversion of hydrosulfide ions (HS-) to elemental sulfur. In the reaction the vanadium ions undergo a valance change from +5 to +4. To reoxidize the Va+4 ions back to the +5 State, ADA is added as an oxygen carrier, and the ADA is subsequently regenerated with air. The process chemistry can be summarized as follows;   CO3-2 + H2S → HS-+HCO3- 4VO3-+2HS-+H2O → V4O9-2+2S+4OH- V4O9-2+2OH-+H2O+2ADA → 4VO3-+2ADA(reduced) 2ADA(reduced)+O2 → 2ADA+H2O A typical flow diagram of a Stretford unit is illustrated in Fig. 1. Although the addition of vanadium to the Stretford Process increases the reaction rate of hydrosulfide ions to sulfur sufficiently to make the process commercial, it still produces a significant amount of byproduct thiosulfate. The reaction is still slow enough that air streams cannot be treated due to the high rate of thiosulfate formation. Hundreds of Stretford units have been installed throughout the world; however, their popularity vanished in the mid 1980’s after the introduction of the chelated iron processes which addressed many of the deficiencies of the Stretford process   Chelated Iron-Based, Liquid Redox Processes Iron is an excellent oxidizing agent for the conversion of H2S to elemental sulfur; however, due to the very low solubility of iron in aqueous solutions, the iron had to be present in the dry state (iron sponge) or in suspensions (the Ferrox process) or compounded with toxic materials such as cyanides. In the 1960’s development work was begun in England to increase the solubility of elemental iron in aqueous solutions. This work led to the introduction of the CIP process, CIP being an acronym for “Chelated Iron Process”. In this process, iron, in its’ ferric state (+3), is held in solution by a chelating agent, namely ethylenediaminetetraacetic acid (EDTA). The intent of the process was to oxidize sulfide (S=) and hydrosulfide (HS-) ions to elemental sulfur by the reduction of the ferric (Fe+3) iron to ferrous (Fe+2) iron, and the subsequent reoxidation of the ferrous ions to ferric ions by contact with air. The chemistry of all chelated iron processes is summarized as follows with (l) and (v) representing the liquid and vapor states, respectively;   H2S(v) + H2O(1) → H2S(1) (1) H2S(1) → H++HS- (2) HS-+2Fe+3+H+ → S0+2Fe+2 (3) 1/2O2(air)+ H2O(1) → 1/2O2(1) (4) 2Fe+2+1/2O2(1)+H2O → 2Fe+3+2OH- (5)   Overall Reaction H2S(v)+1/2O2(v) →(Fe) S0+H2O (6)   Equations 1 and 2 represents the absorption of H2S into the aqueous, chelated iron solution and its subsequent ionization, while equation 3 represents the oxidation of sulfide ions to elemental sulfur and the accompanying reduction of the ferric iron to the ferrous state. Equations 4 and 5 represents the absorption of oxygen into the aqueous solution followed by oxidation of the ferrous iron back to the ferric state. Equations 3 and 5 are very rapid. This is in contrast to the oxidation reactions in the Stretford process when using vanadium. Consequently, iron-based systems generally produce relatively small amounts of byproduct thiosulfate ions, and in properly designed units, air streams can actually be processed. However, as in the Stretford process, equations 1 and 4 are relatively slow and are the rate controlling steps in all chelated iron processes. It is interesting to note that the chelating agents do not appear in the process chemistry, and in the overall chemical reaction, the iron cancels out. So the obvious question is why is chelated iron required at all, if it doesn’t part take in the overall reaction. The iron serves two purposes in the process chemistry. First, it serves as an electron donor and acceptor or in other words, a reagent. Secondly, it serves as a catalyst in accelerating the overall reaction. Because of this dual purpose, the iron is often called a “catalytic reagent”. The chelating agent(s) do not part take at all in the process chemistry. All the chelating agents do is to increase the solubility of iron in water, thus reducing the circulation rates required to furnish the two moles of iron required in equation 3. Although it appears that chelated iron would solve many problems associated with previous liquid oxidation processes, the CIP Process failed miserably. In very short order after starting up, all of the iron precipitated out of solution as iron sulfide, FeS. The problem was that the chelation strength of many chelating agents varies considerably with solution pH, and unfortunately, the pH’s experienced in the CIP process were outside the range of EDTA. In the early 1970’s, a small company in the Chicago area (ARI Technologies) started development work on a process, which employed multiple chelating agents. The idea being that by employing chelating agents with overlapping pH ranges where the chelation strengths were high, the iron would stay in solution at all times. This development work led to the introduction of the LO-CAT® process in the late 1970’s. The process worked well for units processing small quantities of H2S; however, in the first unit processing tons per day of sulfur, the process, in essence, failed. It was found that the chelating agents were disappearing very rapidly requiring extremely high chemical makeup rates. Research found that the chelating agents were being oxidized to useless byproducts by a free radical mechanism. After a few years of experimentation, the chelate oxidation rate was reduced to an acceptable level by the introduction of free radical scavengers and by switching to chelating agents, which were much more resistant to oxidation. Iron-based, liquid oxidation has developed into a very versatile processing scheme for treating gas streams containing moderate amounts of H2S. Advantages of these systems include the ability to treat both aerobic and non-aerobic gas streams, removal efficiencies in excess of 99.9%, essentially 100% turndown on H2S concentration and quantity, and the production of innocuous products and byproducts. The three most common processing schemes encountered in iron-based, liquid oxidation systems are illustrated in Fig. 2 through 4. Fig. 2 shows a “Conventional” unit, which is employed for processing gas streams, which are either combustible or cannot be contaminated with air such as carbon dioxide, which is being treated for beverage purposes. In this scheme, equations 1 through 3 are performed in the Absorber while equations 4 and 5 are performed in the oxidizer. Fig. 3 illustrates an “Autocirculation” unit, which is used for processing acid gas (CO2 and H2S) streams or for other non-combustible streams, which can be contaminated with air. In this scheme, equations 1 through 3 are performed in the “Centerwell” which is nothing more than a piece of pipe open on each end. The purpose of the centerwell is to separate the sulfide ions. from the air to minimize byproduct formation. The volume within the centerwell is essentially the same as the absorber in a conventional unit. The other unique feature of the Autocirculation scheme is that no pumps are required to circulate solution between the centerwell (absorber) and the oxidizer. In these units there is a larger volume of air than acid gas; consequently, the aerated density on the outside of the centerwell is less than on the inside resulting in a natural circulation from the oxidizer into the centerwell. The last type of processing scheme (Fig. 4) is the aerobic unit (air contaminated with H2S) in which equations 1 through 5 all occur within the same vessel, at the same time and without separation of the absorber and the oxidizer. These are generally less expensive units than the other two schemes; however, because there is always oxygen in the presence of sulfide ions, consequently, these units produce the most byproducts.   The Present Although references are continuously made that iron-based, liquid redox systems are plagued with plugging and foaming problems and that the process cannot be operated at high pressure due to pump and foaming problems, these problems for the most part have been solved for some time. Foaming occurrences are either a start-up phenomenon or the result of large amounts of liquid hydrocarbons entering the unit. During the initial start-up of a unit, the surface tension properties of the fresh solution are such that the foaming may occur during the first few days of operation. However, by following proper start-up procedures, this foaming is easily avoided. In addition, this foaming tendency is only experienced when the entire unit is filled with fresh solution, which only happens during the initial start-up of the unit. Foaming does not occur during subsequent start-ups. Continuous incursions of small amounts of liquid hydrocarbons are frequently experienced with no adverse effect on the operation of a unit; however, the introduction of large amounts of liquid hydrocarbons can present foaming and plugging problems. This would also be true of Claus units, selective oxidation processes and hydrocarbon-based, redox systems. However, for aqueous-based redox systems, “Designer” surfactants1 have been developed, which in essence totally alleviates the problems caused by the introduction of large amounts of liquid hydrocarbons. During the early days of liquid redox, sulfur plugging was a severe operating problem. Packing plugged, static mixers plugged, pipes plugged, heat exchangers plugged and distributors plugged. For the most part, all of these plugging problems have been eliminated. Vessels with random packing are no longer used, on-line cleaning procedures have been developed for static mixers1, which require very little operator attention, proper pipe design has eliminated pipe plugging, proprietary heat exchanger designs and proper operating procedures have minimized heat exchanger plugging, newly designed absorber spargers are being installed, which have greatly extended the life of sour gas spargers and improved quality control of oxidizer sparger materials and proper operation of the process has minimized oxidizer sparger plugging. Operation of aqueous-based liquid redox systems at high pressure has been a problem due to difficulties with keeping the liquid circulation pumps running. Circulation pumps were always specified as ANSI, open-impeller centrifugal pumps. The logic being that closed-impeller pumps would plug with sulfur particles or possibly erode. Consequently, for high head applications in which open-impeller pumps would not apply, plunger type pumps were chosen. The plunger pumps had no difficulty supplying the required head; however, seal rings had extremely short lives. To solve this problem, a multi-staged, closed-impeller, centrifugal pump was installed in one high pressure application with excellent results. The pump was in continuos operation for approximately1_ years without any signs of plugging or erosion. For all future high-pressure applications, closed-impeller single or multi-stage centrifugal pumps will be specified. Obviously, the original concern about plugging had no basis.   The Future Although iron-based, liquid redox processes have gained acceptance as evidenced by over 150 units being licensed worldwide, there are still areas in the process, which need to be improved upon. Current areas of R&D efforts are reduction in operating costs, reduction in equipment size and improvement in molten sulfur color. Operating costs for aqueous, iron-based redox systems are composed of replacing chemicals which are either oxidized in the unit or which are physically lost from the unit and of electrical power required for circulating solution and injecting air. For any iron-based system there is an economic tradeoff between iron concentration and the solution circulation rate. Since 2 moles of iron are required for every mole of hydrogen sulfide (equation 3), the amount of circulating solution required is dependent on the iron concentration in the solution and the amount of H2S in the sour gas stream — the higher the iron concentration, the lower the circulation rate and hence, the lower the power consumption. Conversely, the higher the iron concentration, the higher the catalyst makeup rate required to replace iron from physical losses such as solution lost with sulfur withdrawal. There is an optimum iron concentration based on the incremental cost of power and the amount of solution, which is normally lost from the system. This relationship is shown in Figure 5. Besides replacing iron, which is physically lost from the system with the sulfur and blowdown streams, chelating agents are chemically oxidized into useless, non-toxic byproducts within the system and must be replaced. As stated previously, different chelating agents have different resistances to chemical oxidation. In addition, chemicals may be added to the system or made in the unit, which act as free radical scavengers, thus retarding chelate oxidation. Research continues on the development of oxidation resistant chelates and on economical, free radical scavengers. For example, many compounds from the polyamine family have proven to be excellent free radical scavengers reducing chelate degradation to essentially zero. Unfortunately, the oxidation rates of the polyamines are extremely high and consequently, uneconomical. Also new chelating agents have been developed which have very high resistances to oxidation; however, they currently are uneconomical to manufacture. The search for stable chelating agents and/or economical free radical scavengers continues. A large portion of the electrical consumption in an iron-based, liquid oxidation system is associated with blowing air through the solution to satisfy the oxygen demand of equation 5. Due to the low solubility of oxygen in water, a large excess of air is generally employed depending on oxidizer design. Although the air is free, the back pressure on the blowers is usually between 0.5 and 1.0 bar (g), thus the blower usually represents a large portion of the unit’s electrical consumption. A considerable amount of research is currently underway to develop new mass transfer devices which will improve the oxygen utilization in liquid oxidation systems with the aim of reducing the quantity of air required (operating cost) and reducing the size of the oxidizing vessels (capital cost). Currently, there are two types of oxidizers employed -low head and high head oxidizers. In the low head oxidizers air is sparged through approximately 3 meters of solution at superficial air velocities of less than 3.5 M/min by means of distributors equipped with EPDM sleeves which are perforated with very small holes. Solution flow is perpendicular to the airflow. These oxidizers are relatively poor mass transfer devices; however, they do provide much need solution inventory for proper operation of the system. In high head oxidizers air is sparged through approximately 7 meters of solution at superficial velocities of greater than 10 M/min by means of course bubble pipe distributors. Solution flow is co-current to the airflow. These oxidizers provide mass transfer coefficients which are approximately 4 times better than the low head oxidizers; however, this is at the expense of higher discharge heads on the air blowers. Neither the low or high head oxidizers are very good mass transfer devices; however, they generally do not plug with sulfur and they do supply solution inventory required for proper operation of the system. A main goal of current research is to develop a mass transfer device, which will reduce the amount of air required to approximately stoichiometric quantities, will reduce the oxidizer volume and will not plug with sulfur. To this end, special synthetic membranes are being tested. Initial results indicate that the first two objectives of the research — stoichiometric air and high mass transfer coefficients — can be obtained. Long term testing is currently being carried out to determine the plugging tendencies of the membranes. If this last phase of testing is successful, liquid oxidation systems will become much smaller and less expensive to operate. Sulfur produced from liquid redox systems has the same chemical assay as Claus sulfur, and it does have several commercial uses2 in its unmelted form. In fact Lubrizol in France has been recycling its produced sulfur with no adverse effect for quite some time. However, there is always a desire to improve the appearance (color) of redox sulfur, which is degraded due to the presence of iron polysulfides. Development work is being conducted on a variety of filter/wash systems with the goal of removing the chelated iron from the sulfur cake prior to final use. However, due to the extremely low price of sulfur and due to the relatively low quantities of sulfur produced in liquid redox plants, it is difficult justifying much work in this area.   Conclusions Liquid phase oxidation systems have undergone considerable evolution during the 20th century, and this will continue into the 21st century. Foreseeable developments for the near future will be smaller equipment sizes and lower operating costs which will be achieved by the development of better oxygen mass transfer devices reducing the amount of air required and the size of oxidizers and by the addition of free radical scavengers into the systems.

Biomass is defined as the organic material of recent biological origin. Plant-based biomass, which is considered as a suitable feedstock for pyrolysis, is mainly composed of three organic polymers – hemicellulose 20-40%, cellulose 40-60% and lignin 10-25% by weight. During pyrolysis, these organic components are thermally decomposed in the absence of oxygen. This process is irreversible and generally produces numerous chemical species in the form of pyrolysis vapors, aerosols and solid residue. The condensation of pyrolysis vapors and aerosols yields a dark brown colored liquid with a distinct smoky odor called as bio-oil. Non-condensable fraction of pyrolysis vapors usually consists of gaseous species such as carbon monoxide, carbon dioxide, methane and hydrogen. Solid residue obtained from pyrolysis is called as charcoal or char. It consists of dehydration, condensation and re-polymerization products of the non-volatile fragments of hemicellulose, cellulose and lignin that are produced during pyrolysis. The pyrolysis product classification into the above mentioned three product categories based on their physical state of existence: char (solid), bio-oil (liquid) and non-condensable gases (gas) has become a standard over the years. The relative proportions of these three product fractions significantly vary depending upon the process conditions. The purpose of fast pyrolysis is to obtain maximum yield of bio-oil from biomass or other organic feedstocks. High heat transfer rates and temperature around 500°C is necessary to obtain maximum bio-oil yield. Along with the reaction temperature, the residence time of the pyrolysis vapors also plays an important role in the process. It can have following implications on the fate of pyrolysis vapors: 1) secondary cracking in the gas phase – where pyrolysis vapors undergo further degradation producing more low molecular weight compounds and gaseous species. The residence time of the pyrolysis vapors could be minimized by using rapid condensation or by quenching them, however it is difficult to completely eliminate the secondary decomposition reactions. The char particles, which are often entrained in the pyrolysis vapors emerging from the reactor, need to be separated prior to the condensation. This operation needs pyrolysis vapors to go through a char separation unit, which adds to the vapor residence time at high temperatures. 2) Secondary decomposition on the char surface – the vapor-char interactions cause pyrolysis vapors to condense and decompose on the char surface. This decomposition is probably catalyzed by the char. These interactions can take place inside the biomass particles of sufficiently large size or outside the biomass particles before char is separated from the products. These intraparticle vapor-solid interactions are particularly important in case of large size (> 0.5 cm) particles. When such particles are exposed to pyrolysis temperatures, the thermal wave produces a thin pyrolysis front, which travels slowly inwards depending on the rate of internal heat transfer, leaving behind the layer of char. As pyrolysis front moves inwards, the devolatalized vapors have to diffuse out through the layer of char. The char provides good site for pyrolysis vapors to condense and decompose to produce secondary char (or coke) at the expense of bio-oil. Biomass particle size < 2 mm has been recommended for the maximum bio-oil yield. The secondary char formation is also possible on the surface of char entrained in the gas phase, provided enough residence time is available.