MDEA/正丁醇/水相变吸收剂的CO_(2)吸收性能及动力学特性  

CO_(2) absorption properties and kinetics characteristics of MDEA/n-butanol/water phase change absorbent

作　　者：唐建峰[1,2] 陈洁 桑伟[1,2] 许义飞 孙培源 王铭 TANG Jianfeng;CHEN Jie;SANG Wei;XU Yifei;SUN Peiyuan;WANG Ming(College of Pipeline and Civil Engineering,China University of Petroleum(East China),Qingdao 266580,Shandong,China;Shandong Provincial Key Laboratory of Oil and Gas Storage and Transportation Safety,China University of Petroleum(East China),Qingdao 266580,Shandong,China)

机构地区：[1]中国石油大学(华东)储运与建筑工程学院,山东青岛266580 [2]中国石油大学(华东)山东省油气储运安全省级重点实验室,山东青岛266580

出　　处：《低碳化学与化工》2023年第5期115-124,共10页Low-Carbon Chemistry and Chemical Engineering

摘　　要：N-甲基二乙醇胺(MDEA)/正丁醇/水相变吸收剂具有良好的相分离性能,具有大幅降低再生能耗的潜力。由于正丁醇取代了相变吸收剂中的部分水,且相变吸收剂在吸收过程中会发生分相,会对溶液的CO_(2)吸收性能和反应机理造成一定影响,且贫、富相间物质的转移也会对其动力学性能产生一定的影响。为此,研究了MDEA/正丁醇/水相变吸收剂的吸收性能,并通过13CNMR表征测试了不同CO_(2)负荷下溶液的物质组成,分析了MDEA/正丁醇/水相变吸收剂的传质-反应机理,在此基础上探究了其动力学特性。结果表明,溶液中正丁醇的加入,提高了溶液前9min的初始CO_(2)吸收速率,随着正丁醇含量的升高,溶液的CO_(2)吸收速率出现先增高后降低的趋势,CO_(2)吸收负荷逐渐降低。物理溶剂正丁醇不参与反应,相变吸收剂中MDEA与CO_(2)的反应遵循碱催化水和反应机理;分相后贫相溶液主要为MDEA、正丁醇和水,富相溶液主要为MDEA与CO_(2)的反应产物。在CO_(2)吸收负荷较低(小于1.12mol/L)时,由于正丁醇提高了CO_(2)在溶液中的物理溶解度,促进了贫相中MDEA与CO_(2)的快速反应,继而又促进气相CO_(2)的溶解。这种溶解促进反应、反应促进溶解的过程,使得MDEA/正丁醇/水相变吸收剂的初始CO_(2)吸收速率高于MDEA水溶液;在CO_(2)吸收负荷较高(大于1.45mol/L)时,溶液的分相程度已经接近理想分相状态,贫相中的水含量较少,富相中的MDEA浓度较低、反应产物浓度较高,导致CO_(2)与溶液的反应速率降低。N-methyldiethanolamine(MDEA)/n-butanol/water phase change absorbent has good phase separation performance and has the potential to significantly reduce renewable energy consumption.Since n-butanol replaces part of the water in the phase change absorbent,and phase separation occurs during the absorption process of the phase change absorbent,the CO_(2) absorption performance and reaction mechanism of the solution are affected to a certain extent,and the transfer of the rich and lean interphase substances also has a certain impact on its kinetic performance.Therefore,the absorption properties of MDEA/n-butanol/water phase change absorbent were studied,and the material composition of the solution under different CO_(2) loads was tested by 13C NMR characterization,and the mass transfer-reaction mechanism was analyzed.On this basis,the kinetic characteristics were explored.The results show that the addition of n-butanol in the solution increases the initial CO_(2) absorption rate in the first 9 min of the solution.With the increase of n-butanol content,the CO_(2) absorption rate of the solution increases first and then decreases,and the CO_(2) absorption load gradually decreases.The physical solvent n-butanol does not participate in the reaction,and the reaction of MDEA with CO_(2) in the phase change absorbent follows the reaction mechanism of alkali catalyzed water.After phase separation,the lean phase solution is mainly MDEA,n-butanol and water,and the rich phase solution is mainly the reaction products of MDEA and CO_(2).At low CO_(2) absorption load(less than 1.12 mol/L),n-butanol improves the physical solubility of CO_(2) in solution,promotes the rapid reaction of MDEA with CO_(2) in the lean phase,and then promotes the dissolution of CO_(2) in the gas phase.The process of dissolution promoting reaction and reaction promoting dissolution makes the initial CO_(2) absorption rate of MDEA/n-butanol/water phase change absorbent higher than that of MDEA aqueous solution.At high CO_(2) absorption load(more than 1.45 mo

关 键 词：相变吸收剂 CO_(2)吸收性能 反应机理 动力学 

分 类 号：TQ028.17[化学工程] X511[环境科学与工程—环境工程]