The integrated combine cycle coal gasification facility includes a coal gasification plant, an air separation unit (ASU) and a sulfuric acid plant. It produces sufficient amount of syngas used to generate 315 MW of power. (Note: power generation equipment isn’t included).
The coal gasification plant uses entrained-flow, oxygen-blown technology that was developed by Texaco and later purchased by General Electric Co. It has designed capacity of 162 MMSCFD (19,104 m3/hr; 1,896.81 MMBTU/hr) syngas output at 217.7 °F and 315 PSIG. Major compositions in the syngas (vol%): 38.06% H2, 45.23% CO, 12.82% CO2, 2.56% N2.
The ASU is built by Air Products & Chemicals to produce pressured oxygen and nitrogen gas, and liquid nitrogen. The processes used are (1) Air Compressor and purification, (2) liquefaction using expansion turbine refrigeration, (3) separation of the liquid products by cryogenic distillation, (4) storage of liquid nitrogen, (5) vaporization of oxygen and nitrogen to gases, followed by Compressor to meet gasifier, combustion turbine, acid plant, blanketing, and purging requirements. The ASU generated gaseous oxygen (2,100 tons/day of oxygen, minimum purity 95%), gaseous nitrogen (6,000 tons/day of nitrogen, minimum purity 98%) and high-pressure gaseous nitrogen (400 tons/day, minimum purity 99.99%).
The used double-absorption 230 TPD sulfuric acid plant is designed by MECS (Monsanto Enviro-Chem System, Inc.) to process an acid stream from an acid gas removal unit (AGR), an ammonia acid gas stream from an ammonia stripper, and a sulfur dioxide stream from a hot gas cleanup unit (HGCU). The acid gas removal unit is a conventional amine unit using MDEA. The ammonia stripper unit is a steam stripping system that removes the hydrogen sulfide, carbon dioxide, ammonia and other gases from sour water. The hot gas cleanup unit uses a solid reactant to remove sulfur compounds from a gas stream and is then regenerated with dry air. The plant produced industrial grade 98% sulfuric acid. The plant consists of 4 process sections: (1) Formation of sulfur dioxide (SO2) gas in the decomposition furnace with the combustion of H2S gas. (2) Cooling and purification of the SO2 process gas. (3) Convention of the SO2 to sulfur trioxide (SO3) gas. (4) Absorption of the SO3 in sulfuric acid.