卤化法焦化粗苯精制新工艺工业化试验

Pilot test of coking benzene refining by the novel technology halogenated method

针对焦化粗苯中存在的非芳烃(NAH)、二硫化碳和噻吩与苯难以分离的问题,提出了卤化法精制技术。本工业化试验一方面以丙酮为共沸剂,采用共沸蒸馏的方式脱除焦化粗苯中的NAH和二硫化碳;另一方面以卤化反应为手段,将焦化粗苯中的噻吩转化为噻吩衍生物,结合蒸馏技术获取卤化精苯和噻吩衍生物。试验结果表明,经过共沸蒸馏后苯中二硫化碳含量可降低到0.1 mg/kg以下,NAH的质量分数降低到0.1%以下;用KMn O4和Na Br作为卤化剂可以将焦化粗苯中的噻吩转化为2-溴噻吩和2,5-二溴噻吩,通过减压蒸馏回收了高附加值的2-溴噻吩和2,5-二溴噻吩,相应产物的质量分数均大于98%。同时,经蒸馏获得的卤化精苯总硫含量小于1 mg/kg。

The halogenation method for the refining of coking benzene has been proposed due to the existing technical problems in separation of non-aromatic hydrocarbon（ NAH）,carbon disulfide,thiophene and benzene by distillation. In the pilot test,the NAH and carbon disulfide in the coking benzene are removed by azeotrope distillation technology with acetone as entrainer. The thiophene is converted into its derivatives by means of halogenation reaction.The benzene and thiophene derivatives are then recovered via distillation. The results of the pilot test indicate that the concentration of NAH in the benzene could be reduced to below 0. 1% and carbon disulfide to 0. 1 mg / kg by azeotrope distillation using acetone as entrainer. The thiophene in the coking benzene is changed into 2-bromothiophene and 2,5-dibromothiophene by applying KMn O4 and Na Br as halogenated agents. The high added value of thiophene derivatives could be recovered by using vacuum distillation. The purity of thiophene derivatives are above 98%. Meanwhile,the refined benzene is also recovered through distillation,with the total sulfur content less than 1 mg / kg.