The evaluation of a process for clean syngas based on lump coal pressurized gasification

Abstract

Raw Gas generated from LCPG (lump coal pressurized gasifier) contains quantities of organics including methane so that it is not suitable as syngas. A process was proposed to solve this problem, and Aspen Plus was used to discuss its possibility that Raw Gas was reformed to clean syngas through introducing oxygen on the principle of thermodynamic equilibrium. The simulation results reveal that almost all organics are completely converted to simple substances such as hydrogen and carbon monoxide whether or not to preheat. Raw Syngas and wastewater no longer contain various organic pollutants eliminated difficultly besides very small amounts of ammonia and hydrogen sulfide, which certainly simplifies the purification and post-treatment processes. A Raw Syngas with H2/CO ratio of 2.0 was attained under the operating condition of 2.35 Mpa and 918 °C. Such H2/CO ratio is higher than those of coal gas derived from existing gasification technologies. Meanwhile, the total yield and content of the effective gas (CO + H2) have been increased to 1109 m3/t and 72.0% respectively in the preheating process, and GE (gasification efficiency) rises to 84.8%. The OC (oxygen consumption), CC (coal consumption) and SC (steam consumption) have been reduced by 47.3%, 50.7% and 49.4% respectively compared with LCPG. In addition, the feasibility of this process was further verified with kinetic simulation.