年产100万t甲醇合成流程模拟及影响因素考察

Simulation of methanol synthesis process with annual output of 1 million tons and investigation of influencing factors

甲醇是重要的基础化工原料之一,为了实现合成气制甲醇的高效利用,采用流程模拟软件Aspen Plus建立年产100万t甲醇模型。首先,在一定假设条件下,采用Aspen Plus建立基于平衡反应器的甲醇合成反应器模型,合成气采用粉煤加压气流床气化炉产生的煤气,对国内某年产100万t甲醇厂进行模拟,结果显示模拟结果与实际运行数据基本吻合,原料气与驰放气组成的设计值与实际模拟值组分绝对偏差在±2%以内,达到工业化模拟精度要求。在此模型基础上,探究了BGL气化炉所产生的合成气、固态排渣碎煤加压气化炉所产生的合成气在甲醇合成过程中循环比对甲醇产率的影响。结果表明,原料气H/C比均为2.05,BGL气化、固态排渣碎煤加压气化所产生的甲醇合成原料气吨甲醇有效气(CO+H_(2))消耗分别为2247 Nm^(3)和2461 Nm^(3)。2种原料气随着甲烷含量升高,原料气中的H_(2)、CO、CO_(2)的转化率降低,甲醇产率降低。在操作条件不变的情况下,随着循环比从1.5上升至5.0,甲醇产量呈现抛物线上升趋势,BGL气化原料气、固态排渣碎煤加压原料气在甲醇合成中只有循环比分别不低于2.00和4.93时,甲醇年产量才能达到100万t,压缩机功耗随着循环比提高而呈现线性上升的趋势。

Methanol is one of the important basic chemical raw materials.In order to realize the efficient utilization of synthesis gas to methanol,the process simulation software Aspen Plus is used to establish a methanol model with an annual output of 1 million tons.Firstly,under certain hypothetical conditions,Aspen Plus is used to establish a methanol synthesis reactor model based on an equilibrium reactor.The synthesis gas is the gas produced by the pressurized pulverized gasifier.The simulation results of a domestic methanol plant with an annual output of 1 million tons show that the simulation results are basically consistent with the actual operation data.The absolute deviation between the design value composed of feed gas and purge gas and the actual simulation value is within±2%,the precision of industrial simulation is achieved.On the basis of this model,the influence of recycle ratio of syngas from BGL gasifier and syngas produced by solid slag discharge pulverized coal pressurized gasifier on methanol yield during methanol synthesis were explored.The results show that the H/C ratio of feed gas is 2.05,and the effective gas consumption ton of methanol synthesis feed gas produced by BGL gasification,solid slag removal and crushed coal pressurized gasification is 2247 Nm^(3) and 2461 Nm^(3) respectively.With the increase of methane content in the two feed gases,the conversion of H_(2),CO and CO_(2) in the feed gas decreases,and the methanol yield decreases.Under the same operating conditions,as the circulation ratio increases from 1.5 to 5.0,the methanol output shows a parabola rising trend.Only when the circulation ratio of BGL gasification feed gas and solid slag removal crushed coal pressurized feed gas in methanol synthesis is not lower than 2.00 and 4.93 respectively,the annual methanol output can reach 1 million tons.The compressor power consumption shows a linear rising trend with the increase of the circulation ratio.