脂肪醇聚氧乙烯醚对Urea-SCR沉积物的影响  

Effects of fatty alcohol polyoxyethylene ether surfactants on Urea-SCR sediment

作　　者：赵扬 庄圆 李丽莎 解润中 王明霞[2] 严峰[2] ZHAO Yang;ZHUANG Yuan;LI Li-sha;XIE Run-zhong;WANG Ming-xia;YAN Feng(Tianjin Yuetai Petroleum Technology Company,Tianjin 300384,China;School of Chemical Engineering and Tech-nology,Tiangong University,Tianjin 300387,China;Second Oil Production Plant,Changqing Oilfield,Qingyang 745106,Gansu Province,China)

机构地区：[1]天津悦泰石化科技有限公司,天津300384 [2]天津工业大学化学工程与技术学院,天津300387 [3]长庆油田采油二厂,甘肃庆阳745106

出　　处：《天津工业大学学报》2021年第5期55-61,共7页Journal of Tiangong University

基　　金：天津市自然科学基金面上资助项目(18JCYBJC89300)。

摘　　要：针对柴油车尾气处理液即尿素(Urea)溶液在选择性催化还原(SCR)系统中因尿素不完全分解而产生沉积物问题,制备了不同结构直链脂肪醇聚氧乙烯醚表面活性剂,采用吊片法测定了表面活性剂的表面张力和临界胶束浓度(CMC),采用界面扩张流变仪测试了表面活性剂的表面扩张模量,采用模拟台架实验考察了表面活性剂结构和浓度对沉积物抑制效果的影响。结果表明:环氧乙烷(EO)数为5的表面活性剂的CMC和表面张力均较低,即表面活性较高,其中,C_(14)EO_(5)的CMC达到10^(-6) g/mL数量级,表面张力达28.32 mN/m;C_(14)EO_(5)在浓度接近CMC时,表面扩张模量远高于其他表面活性剂,形成的表面膜强度最高,有利于形成高分散度的喷雾液滴;脂肪醇聚氧乙烯醚对SCR系统沉积物的影响与表面活性剂结构密切相关,表面活性和表面扩张模量最高的C_(14)EO_(5)对沉积物的抑制效果最明显,沉积物的减少率达到了46.2%。Aiming at the problem of sediments due to incomplete decomposition of urea in the selective catalytic reduction(SCR)system of diesel vehicle exhaust gas treatment fluid(Urea solution),the linear fatty alcohol polyoxyethylene ether surfactants with different structures were prepared as additive for the urea solution.The surface tension and critical micelle concentration(CMC)of the surfactant were measured by the hanging plate method(Wilhelmy method),and the surface expansion modulus of the surfactant was measured by the interfacial expansion rheometer.The simulation bench experiment was used to investigate the influences of surfactant structure and concentration on sediment inhibition in the SCR system.The results show that the CMC and surface tension of surfactants with ethylene oxide(EO)number of 5 are lower than those of EO=10.The CMC of C_(14)EO_(5) reaches 10^(-6) g/mL,and the surface tension is 28.32 mN/m.When the concentration of C_(14)EO_(5) is close to CMC,the surface dilational modulus is much higher than that of other surfactants,indicating that the surface film formed has the highest strength,which is benefit for the formation of highly dispersed spray droplets.The influence of fatty alcohol polyoxyethylene ether on SCR system sediments is closely related to the structure of surfactants.C_(14)EO_(5),which has the highest surface activity and surface dilational modulus,has the most obvious inhibitory effect on sediments,and the reduction rate of sediments reaches 46.2%.

关 键 词：直链脂肪醇聚氧乙烯醚 尿素 选择性催化还原 表面活性剂 表面张力 表面扩张流变 沉积物 

分 类 号：TQ423.22[化学工程]