SDS与THF对水合物法分离CO_2+N_2混合气的影响  

Effects of SDS and THF on the separation of CO_2+N_2 mixed gases based on the hydrate method

作　　者：李玉星[1] 陈玉亮 

机构地区：[1]中国石油大学(华东)储运与建筑工程学院 [2]中国石油西气东输管道分公司

出　　处：《天然气工业》2011年第7期82-86,112,共5页Natural Gas Industry

基　　金：国家自然科学基金"水合物颗粒聚集动力学及流动安全研究"(编号:51006120);山东省自然科学基金"含水合物的相平衡体系中气体溶解度研究"(编号:ZR2009FM036);教育部新世纪人才支持计划(编号:NCET-07-0847)

摘　　要：水合物添加剂在一定程度上能够解决纯水体系下水合物分离混合气存在选择性低、水合速率不高和水合物生成条件苛刻等问题，为了系统地研究十二烷基硫酸钠（SDS）及四氢呋喃（THF）对水合物分离特性的影响，采用自行设计的水合物分离实验装置，分别进行了浓度为0、100mg／kg、300mg／kg、500mg／kg、1000mg／kg的SDS溶液及摩尔分数为0、0．5％、1．0％、3．0%的THF溶液体系下，水合物法分离摩尔分数为59%的CO2和摩尔分数为41％的N。混合气的实验。实验结果表明：SDS能够提高水合物的生成速率及储气密度，随着SDS浓度的增大，CO2分离率与N2损失率都呈现先增大后减小的趋势，分离因子呈现先减小后增大的趋势，在初始压力为5．0MPa、温度为1．4℃的情况下，SDS浓度为O～100mg／kg时水合物分离效果较佳；THF有效地降低了水合物的相平衡压力，THF本身生成Ⅱ型水合物并占据水合物的大孔穴，CO2优先于N2占据水合物的小孔穴，当初始压力为4．8MPa、温度为1．4℃时，THF摩尔分数约为1．0％时能够较好地改善水合物的分离效果。Hydrate additives can be used to solve such problems as low selectivity,low formation rate and harsh formation condition of gas mixture separation in pure water system.Thus,in order to investigate into how the sodium dodecyl sulfate(SDS) and tetrahydrofuran(THF) affect the hydrate separation performance,we adopted our self-designed apparatus for such experiments.The gas mixture of 59% CO2 and 41% N2 were separated in the prepared solutions of 0,100,300,500,and 1000 ppm(mg/kg) sodium dodecyl sulfate(SDS) and 0,0.5,1.0,and 3.0 mol% tetrahydrofuran(THF) respectively.The results show that SDS can accelerate hydrate formation rate and gas storage capacity.With the increment of SDS concentration,the CO2 separation rate and N2 loss rate both increase at first but then decrease.The CO2 separation rate and N2 loss rate rise high to the maximum,the separation factor reduces to the minimum when the SDS concentration is about 230 ppm.In short,the separation effect is passable when the SDS concentration is 0-100 ppm at 5.0 MPa(initial pressure) and 1.4℃.THF can lower hydrate phase equilibrium pressure,the reason of which is that THF can form structure II hydrate and occupy large cage(51264),CO2 has precedence to N2 to occupy small cage(512).The separation effect is satisfactory when the molar ratio between THF and CO2 is 1∶2 in hydrate phase.In short,the separation effect is passable when the THF concentration is about 1.0 mol% at 4.8 MPa(initial pressure) and 1.4℃.

关 键 词：水合物分离法 混合气 SDS THF 分离特性 分离率 损失率 分离因子 

分 类 号：P744.4[天文地球—海洋科学]