Simulation And Exergy Analysis Of CWS And Pulverized Coal Gasification Processes

China is a coal-dependent country.In recent years,coal clean utilization technologies have being developed.Coal gasification is an important way in coal clean utilization.A suitable coal gasification process is an effective way to improve energy performance.Therefore,in this thesis,process simulation,exergy analysis and energy consumption of coal gasification process are investigated.The entrained flow bed coal gasification process is simulated by the balance model with equilibrium temperature approach,which is based on the Gibbs free energy minimization principle.Then this model is verified by industrial data from two typical entrained flow bed coal gasification processes(Texaco CWS gasification process and Shell pulverized coal gasification process).The model is applied to discuss effects of equilibrium temperature approach on simulation results of different gasifiers.The effects of operating parameters on gasification process,condensate flow rate and carbon scrubber pressure on water/vapor ratio are also considered.According to the simulation results of different coal gasification processes,exergy efficiency of the processes and exergy losses of each unit are calculated by exergy analysis method.The results shows that the exergy efficiency of Shell process is the highest,the second one is Texaco process with waste heat boiler,and the lowest one is Texaco process with direct quench.Then based on GB/T 50441-2007,energy consumption of each gasification process is calculated and analyzed.