Used 15,000 TPY Formaldehyde Resin Plant. This plant consists of 2 production sections: the formaldehyde facility and the resin facility. It has a capacity from 10,000 - 15,000 TPY. In the formaldehyde plant, imported methanol is continuously pumped from the methanol storage tanks and vaporized in an evaporator by heating steam. The methanol vapor is then mixed in a fixed proportion with air before passing the mixture to a reactor. The methanol is oxidized to formaldehyde when it comes into contact with the hot (molybdenum / ferric oxide) catalyst inside the reactor. The reaction gas then flows to an absorption column where the formaldehyde gas is scrubbed from the gas stream by a counter-current of demineralized water, flowing from the top of the column. The formaldehyde gas dissolves in the demin water, yielding a formaldehyde solution of approximately 45% strength, which is then cooled and pumped to storage. In the resin plant, two stirred reactors are used to make urea-formaldehyde (UF) resin or melamine-formaldehyde (MF) resin in a batch process. The reaction between formaldehyde and urea (or melamine) in an alkaline medium is called METHYLATION REACTION. Once the reaction temperature has been reached, the mixture of formaldehyde and urea (or melamine) is acidified to an approximately pH of 5.5 by adding acetic acid. Once the viscosity of the reaction medium is reached to specification, the reaction is terminated by raising the pH to above 7.0 by adding caustic soda. The resin is then cooled and concentrated by evaporating excess water under vacuum. A second addition of urea (or melamine) is then added after the resin has cooled further. The batch is then filtered, cooled again, and then pumped to storage. Different grades of resin products can be manufactured by varying the quantities of raw materials and additives, or by alternating process parameters such as temperature, pH, viscosity, etc. The resin products are sold as thermosetting adhesives, used in the manufacture of chipboard, fiberboard, plywood, laminates and veneers.