煤层气组成对模块化生产过程的影响分析

Effects of Coalbed Methane Composition on Modular Manufacturing Process

基于5组典型的煤层气(CBM)组成,建立了煤层气液化过程和煤层气制甲醇过程的模拟模型,同时调整CO_(2)含量至适合甲醇合成的氢碳比((nH_(2)-nCO_(2))=(nCO+nCO_(2)));进行了质量平衡、能耗和经济分析,并探究关键组分N_(2)、CO_(2)、CH_(4)对煤层气液化和煤层气制甲醇过程的影响规律。质量平衡与能耗分析结果表明:CO_(2)可以改善制甲醇过程中合成气的氢碳比,但是会增大液化过程中的脱碳能耗;N_(2)的存在会导致甲烷更难液化,也会增大合成气的循环量及相应的能耗,是煤层气加工的不利因素。经济分析结果表明:高纯度的煤层气液化收益更高;含CO_(2)的煤层气更适宜制甲醇,且制甲醇过程对煤层气组成的适应范围更广;N_(2)含量过高会导致两种加工方式都失去经济吸引力。

A modular plant has the characteristics of small scale,mobility,and flexible production,which is a promising way for stranded coalbed methane(CBM).However,the variable composition of CBM brings uncertainties to the process performances.Based on five typical CBM compositions,simulation models of CBM liquefaction process and CBM to methanol process are established.The supplementary of CO_(2) is also considered to adjust to the hydrogen to carbon ratio suitable for methanol synthesis.The mass balance,energy consumption,and economic analysis are then carried out to explore the effects of each key component on the CBM liquefaction process and CBM to methanol process.The results of mass balance and energy consumption analysis show that CO_(2) in CBM can improve the hydrogen to carbon ratio of syngas in the CBM to methanol process,but it increases the energy consumption of decarbonization in the CBM liquefaction process;The presence of nitrogen makes methane more difficult to be liquefied,and it also increases the recycling syngas and the associated energy consumption in the CBM to methanol process.Nitrogen is an unfavorable factor for CBM processing.The economic analysis shows that liquefaction of high-purity CBM can obtain a higher net present value.The CBM containing carbon dioxide is more suitable for methanol production,and the methanol production process is preferred for a wider range of CBM compositions.The high nitrogen content makes the two processing methods lose economic attraction.