地下煤制气制取液化天然气和液氢工艺研究  

Process research on producing liquefied natural gas and liquid hydrogen by using underground coal-to-gas

作　　者：刘恩斌 鲁绪栋 季永强 彭杰 郝天舒 李茜 LIU Enbin;LU Xudong;JI Yongqiang;PENG Jie;HAO Tianshu;LI Xi(Petroleum Engineering School,Southwest Petroleum University,Chengdu,Sichuan,China;Shanghai Liquefied Natural Gas Co.,Ltd,Shanghai,China;North China Oil and Gas Branch of China Petroleum and Chemical Corporation,Zhengzhou,Henan,China)

机构地区：[1]西南石油大学石油与天然气工程学院 [2]上海液化天然气有限公司 [3]中国石油化工股份有限公司华北油气分公司

出　　处：《石油与天然气化工》2024年第1期61-68,共8页Chemical engineering of oil & gas

基　　金：四川省自然科学基金项目(2023NSFSC0422)。

摘　　要：目的脱除地下煤制气中的酸气,将地下煤制气中的CH_(4)和H_(2)分离出来并液化。方法对常见的分离方法进行对比,确定采用低温精馏法对煤制气进行脱酸气、分离CH_(4)和H_(2)并液化。根据低温精馏法的原理,设计了一种全新的地下煤制气脱酸气、分离CH_(4)和H_(2)并液化的工艺流程,该工艺主要由两个精馏塔、一个两相分离器和三级氦膨胀制冷系统组成。同时利用HYSYS软件对其进行模拟分析,确定最优参数。结果该工艺可以将地下煤制气中CO_(2)的摩尔分数脱除到0,H_(2)S的摩尔分数脱除到3.65×10-14,满足处理要求。同时可以实现CH_(4)回收率为99.97%,加压液化天然气(PLNG)的摩尔分数为99.97%,H_(2)的回收率为98.30%,液氢(LH_(2))的摩尔分数为99.99%。结论该工艺可以有效利用地下煤制气制取PLNG和LH_(2),且所需能耗较传统工艺能耗降低了11.64%,具有较高的经济效益。Objective The aim is to remove the acid-to-gas,separate and liquefy CH_(4)and H_(2)in underground coal-to-gas.Methods Comparing the common separation methods,the low temperature rectification method is determined to use for removing acid gas,separating and liquefying CH_(4)and H_(2).According to the principle of cryogenic rectification,a new process is designed for underground coal-to-gas to remove acid gas and separate and liquefy CH_(4)and H_(2).This process mainly consists of two rectification towers,a two-phase separator and three-stage helium expansion refrigeration system.Simultaneously,HYSYS software is used to simulate and analyze the process for determination of its optimal parameters.Results This process can remove the molar fraction of CO_(2) to 0 and H_(2)S to 3.65×10-14,meeting the processing requirements.At the same time,the recovery rate of CH_(4)is 99.97%,the molar fraction of pressurized liquefied natural gas(PLNG)is 99.97%,the recovery rate of H_(2)is 98.30%,and the molar fraction of liquid hydrogen(LH_(2))is 99.99%.Conclusions This process can effectively use underground coal-to-gas to produce PLNG and LH_(2),and the required energy consumption is 11.64%lower than that of traditional processes,which has high economic benefits.

关 键 词：地下煤制气 低温精馏法 脱酸气 加压液化天然气 液氢 

分 类 号：TD84[矿业工程—煤矿开采] TQ116.2[矿业工程—矿山开采]