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生产低硫、低烯烃和高辛烷值的清洁汽油,是国家保持能源经济可持续发展的必然要求。由于我国原油组成中重质油比重较大,造成我国80%以上的商品汽油来源于流化催化裂化(FCC)汽油。缘于原油性质和FCC的工艺特点,决定了其产品中硫含量和烯烃含量高,商品汽油中90%以上的硫和绝大部分烯烃均来自于FCC汽油。所以,降低FCC汽油硫含量和烯烃含量是生产清洁汽油的关键。本文分析全馏分流化催化裂化汽油加氢改质前后烃类组成、碳数分布、辛烷值贡献的变化。改质前,正构烷烃含量占汽油馏分的5%～10%(体积分数)左右,异构烷烃含量占汽油馏分的30%(体积分数)左右,烯烃含量占汽油总量的30%(体积分数)以上,环烷烃主要集中在C6～C8之间,芳烃主要分布在C7～C10之间,碳数主要分布在C5～C8之间。改质后,正构烷烃、烯烃含量下降,异构烷烃和芳烃含量上升,总体辛烷值下降,高辛烷值的C5、C6烯烃损失严重。在反应体系中,增加烯烃的骨架异构化,并使其发生氢转移反应,可生成高辛烷值的异构烷烃,避免低辛烷值的正构烷烃生成,同时促进烯烃自身氢转移和烯烃与环烷烃之间氢转移反应,增产芳烃,可以提高改质后FCC汽油的辛烷值,为流化催化裂化汽油加氢改质路线的选择和工艺优化提供理论指导。
The production of clean gasoline with low sulfur, low olefins and high octane is a necessary requirement for the country to maintain a sustainable energy economy. Due to the large proportion of heavy oil in the composition of China’s crude oil, more than 80% of the gasoline in our country is derived from fluid catalytic cracking (FCC) gasoline. Due to the nature of the crude oil and the characteristics of the FCC process, the sulfur content and the olefin content in the product are determined. More than 90% of the sulfur and most of the olefins in the commercial gasoline come from the FCC gasoline. Therefore, reducing FCC gasoline sulfur content and olefin content is the key to producing clean gasoline. This paper analyzes the changes of hydrocarbon composition, carbon number distribution and octane value before and after hydrogenation reforming of full-fraction FCC gasoline. Before the reforming, n-paraffins account for about 5% to 10% (volume fraction) of the gasoline fraction, iso-paraffins account for about 30% (volume fraction) of the gasoline fraction, olefin content accounts for 30% of the total gasoline Fraction), naphthenic mainly concentrated in the C6 ~ C8, aromatics are mainly distributed in the C7 ~ C10 between the carbon number is mainly distributed in the C5 ~ C8 between. After the modification, normal paraffins, olefin content decreased, the content of isoparaffin and aromatics increased, the overall octane number decreased, and high octane C5 and C6 olefins lost serious. In the reaction system, increase the skeletal isomerization of olefins, and make it hydrogen transfer reaction, can generate high octane isoparaffin, to avoid the low octane n-paraffins, while promoting olefin hydrogen transfer and Hydrogen transfer reaction between olefins and naphthenes to increase the production of aromatics can increase the octane number of the FCC gasoline after the reforming so as to provide theoretical guidance for the selection and process optimization of the hydrotreating reforming of the FCC gasoline.