水滑石负载碳酸钾的微波法制备及其催化酯化原油脱酸性能

Preparation of hydrotalcite-supported potassium carbonate catalyst by microwave for removing acids from crude oil by esterification

用微波法在水滑石上负载K2CO3,作为原油酯化脱酸催化剂。研究了浸渍法、超声波法、微波法和机械混合法四种制备方法,微波处理时间和K2CO3负载量对催化剂性质和活性的影响。结果表明,兼具高的水滑石结晶度,良好的K2CO3分散度和高碱量的催化剂有最佳脱酸活性。微波法在保持K2CO3高分散的同时明显缩短水滑石和K2CO3溶液的接触时间,从而保持水滑石的高结晶度,且有助于K与水滑石产生更多碱性中心,得到的催化剂脱酸活性最高。K2CO3负载量15%,微波处理5 min制备的催化剂,在200℃,反应时间2 h,催化剂和醇用量分别为原油质量的1%和2%时,对绥中高酸值原油的脱酸率可从水滑石的89.2%提高到97.7%。

Potassium carbonate was supported on hydrotalcite by microwave radiation and used as catalyst to remove acids from crude oil.To better understand the influence of the preparation method on the properties and activity of the catalyst,a series of catalysts with the same K2CO3 content were prepared by impregnation,ultrasonic,microwave radiation and mechanical mixing methods,respectively.Their properties were characterized by XRD,N2 adsorption-desorption and Hammett indicator-benzene carboxylic acid titration.Moreover,their catalytic activity was tested by esterification deacidification reaction between high-acid crude oil and glycol.In addition,the effect of microwave radiation time and the K2CO3 content was also investigated.The presence of carboxyl acid in crude oil and ester in deacidified oil was characterized by FT-IR.It was found that the catalyst with high hydrotalcite crystallinity,well-dispersed K2CO3 and more basic sites shows the best deacidification activity.Among the four methods,microwave radiation can provide adequate energy to disperse K2CO3 species on the surface of hydrotalcite homogeneously and rapidly,and thus can greatly reduce the contacting time of hydrotalcite and basic K2CO3 solution to keep the regular layer structure of hydrotalcite.Furthermore,microwave radiation can produce a high temperature instantaneously,which strengthens the interaction of K＋ and hydrotalcite to promote the formation of more basic sites.The catalyst loading 15% K2CO3 and radiated by microwave for 5min showed superior activity,which can increase the deacidification ratio from 89.2% to 97.7% and decrease the acid number of Suizhong high-acid crude oil from 3.72mgKOH/g to 0.08mgKOH/g at 200℃,at a reaction time of 2h and at catalyst and glycol mass ratios to crude oil of 1% and 2%,respectively.