SYSTEMATIC PERFORMANCE ANALYSIS OF HYDROGEN AND POWER CO-PRODUCTION SYSTEM BASED ON CO2 SORPTION ENHANCED COAL GASIFICATION

摘要

This paper proposed a kind of hydrogen production / power generation system andinvestigates its performance from the point of view of chemical energy conversion and greenhouse gas (GHG) emissions. This system had the advantage of nearly zero emission. It was basedon CO_2 sorption enhanced coal gasification technique and SOFC power generation. Syngas ofgasification was mainly composed of 60-90% hydrogen and 10-40% methane. Contents of CO_2and CO can be lower than 1%. In order to investigate the performance of gasifier, which in fact, isfar beyond chemical equilibrium, a gasification kinetics unit model was developed based onchar-gas, gas-gas, absorbent-CO_2 reaction kinetics. This model can predict the gas composition,syngas yield, solid(unconverted char, ash, unconverted absorbent, limestone) content in bedmaterials. Gasification operation conditions (temperature, pressure,) will determine carbonconversion ratio, gases qualities and quantity of gasification process. Syngas yield and gas contentwill then determine performance (thermal efficiency, CO_2 emissions) of co-production system.Systematic study was done by way of flowsheet simulation and parameters sensitive studies.Influence of key operation conditions on units and system can then be analyzed. Results providedways to system optimization.