典型气流床煤气化炉气化过程的建模

Modeling of coal gasification reaction in typical entrained-flow coal gasifiers

利用Aspen Plus、基于热力学平衡模型对GSP煤粉气化炉、GE水煤浆气化炉及四喷嘴对置式水煤浆气化炉的气化过程建模。根据煤颗粒热转化的历程,将煤气化过程划分为热解、挥发分燃烧、半焦裂解及气化反应4个阶段,利用David Merrick模型计算热解过程,采用Beath模型校正压力对热解过程的影响,选用化学计量反应器模拟挥发分燃烧反应,编制Fortran程序计算半焦裂解产物收率,最后基于Gibbs自由能最小化方法计算气化反应。结果表明,采用建立的气流床气化过程模型模拟工业气化过程的结果与生产数据基本吻合,对GSP煤粉气化炉、GE水煤浆气化炉及四喷嘴对置式水煤浆气化炉等3种气化炉有效气成分(CO+H_2)体积分数模拟结果的误差均不超过2%,建立模型的可靠性得到验证。

This paper presents a modeling method for the coal gasification process proceeding in GSP pulverized coal gasification,GE coal-water slurry gasification and Opposed Multiple-Burner gasification based on the thermodynamic equilibrium with the aid of Aspen Plus. In the light of thermal conversion procedure of fine coal particles,the coal gasification was interpreted as consisting of four stages including pyrolysis,volatile combustion,char decomposition and gasification reaction. Then, the pyrolysis stage was calculated by the David Merrick model and the effect of pressure on the coal pyrolysis was corrected by means of Beath model. The volatile combustion stage was simulated by using Rstoic reactor and the yield of char decomposition products was calculated viacompiling Fortran program. And finally,the gasification reaction stage was simulated based on the Gibbs free energy minimization. The results revealed that the simulated values from the developed simulation model of gasification processes were in good consistent with the industrial field data. The deviation of simulated results of volume fraction of the effective gas （CO＋H2） of these three typical entrained-flow gasifiers were all less than 2%,which can validate the reliability of the coal gasification model.