Key Laboratory for Thermal Science and Power Engineering of Ministry of Education,Tsinghua University

Pulverized coal airflow bed has the advantages of low oxygen consumption, low coal consumptionand high carbon conversion rate,and is widely used in industry. Radiant syngas cooler can effectively recover thewaste heat of syngas produced by pulverized coal gasifier,which is more economical and environmental friendly in thelong run. A steady state model of coal gasifier with radiant syngas cooler (RSC) was constructed using AspenPlus. Since the temperature of RSC is quite high,the further gasification reaction was considered in this model. Moreo⁃ver,the heat loss and unburned carbon was considered according to the industrial experience data and the simulation isvalidated as reliable by industrial operation results. Based on the model,the influences of core operation parameterslike oxygen⁃coal ratio,steam⁃coal ratio and carbon conversion rate were analyzed to provide a theoretical guidance. Thestudy results show that the effective composition of syngas increases rapidly at first and then decreases graduallywith the increase of oxygen⁃coal ratio,and reaches the peak value when the oxygen⁃coal ratio is 0.5. When the oxy⁃gen⁃coal ratio is lower than 0.5,the gasification temperature increases slightly with the oxygen⁃coal ratio and when theoxygen⁃coal ratio is between 0. 5 and 1, the gasification temperature increases rapidly with the oxygen⁃coalratio. When the oxygen⁃coal ratio is higher than 1, the gasification temperature almost remains unchanged.Since the gasification temperature should be higher than ash fusion point to facilitate discharging slag in furnace,theoxygen⁃coal ratio is suggested to be higher than 0.6. The effective composition of the syngas (CO+H2) almost decrea⁃ses linearly with the increase of steam-coal ratio. The effective composition of the syngas (CO+H2) almost increaseslinearly with the increase of carbon conversion rate. The gasification temperature decreases linearly with the increase ofsteam⁃coal ratio and carbon conversion rate.