Development of Separation Process for Potential Gasoline Additives by Pervaporation

碳酸二甲酯（DMC）、t-戊基甲基醚（TAME）和甲基-t-丁基醚（MTBE）等辛烷增强剂作为一种潜在的汽油添加剂近年来备受关注。这些辛烷增强剂基本上是在酸性催化剂上与甲醇（MeOH）反应产生的。由于反应是可逆的，需要将未反应的MeOH从产物溶液中分离出来，再循环到反应器中。然而，甲醇与这些辛烷增强剂形成共沸物，难以通过蒸馏分离。从节能的角度来看，亲水性膜渗透蒸发技术是一种很有前途的分离技术，可优先从甲醇-有机混合物中渗透甲醇。在水醇混合物渗透汽化过程中，经水解的聚丙烯腈和多离子络合物膜具有较高的通量和较高的分离系数。这些膜也可以有效地从共沸的MeOH- dmc或TAME混合物中分离MeOH。从以往的研究来看，有机-无机杂化膜对MeOH-MTBE混合物的分离是有益的。通过模拟实验对该工艺进行了能效评价，发现膜分离工艺是生产MTBE的可行工艺。

The octane-enhancers such as Dimethyl carbonate (DMC), t-Amyl methyl ether (TAME) and Methyl-t-butyl ether (MTBE) have attracted much attention in recent years as a potential gasoline additive. These octane-enhancers are produced by essentially the reaction with methanol (MeOH) over an acidic catalyst. As the reaction is reversible, it is required to separate unreacted MeOH from the product solution for recycling to the reactor. However, MeOH forms an azeotrope with these octane-enhancers, which is difficult to separate by distilllation.As one promising separation technology from view of energy-saving point, pervaporation using hydrophilic membranes have been applied to preferentially permeate MeOH from MeOH-organic mixtures.In pervaporation of water-alcohol mixtures, the hydrolyzed polyacrylonitrile and polyion complex membranes, which are hydrophilic membranes were found to provide with high flux and emhanced separation factor. These membranes was also effective for the separation of MeOH from the azeotropic MeOH-DMC or TAME mixture. From the father investigation, the organic-inorganic hybrid membrane was useful to the separation of MeOH-MTBE mixture.Moreover, the energy efficiency was evaluated by using simulator and the process with membrane separation was found to be available for the production of MTBE.