循环氢脱硫系统在催化汽油加氢脱硫装置的应用

Application of circulating hydrogen desulfurization system in FCC gasoline hydrodesulfurization unit

为了生产硫含量满足国V/国Ⅵ标准的车用汽油,中国石油兰州石化公司180万t/a催化汽油加氢脱硫装置增加了二段加氢脱硫单元以及相应的循环氢脱硫系统,然后针对运行中出现的富胺液外送不畅、富胺液携带油和烃、脱硫塔液位假指示的问题,实施了相应对策。运行结果表明:循环氢脱硫系统不仅能有效脱除加氢脱硫反应生成的H2S,降低循环氢中H2S含量,抑制了硫醇的生成,而且对提高该装置的循环氢纯度和脱硫率,降低装置氢耗和汽油研究法辛烷值(RON)损失具有重要作用;通过调控循环氢中的H2S含量从100μg/g降低到50μg/g,在一段、二段加氢脱硫单元反应温度为248℃时,一段、二段加氢脱硫单元脱硫率分别提高了6,4个百分点;在一段、二段加氢脱硫单元重汽油产品中含硫量分别为40,9μg/g条件下,一段、二段加氢脱硫单元的反应温度、重汽油硫醇含量、RON损失相应分别降低了4,4℃;3,2μg/g;0.3,0.4个单位;在一段、二段加氢脱硫单元处理量为175 t/h条件下,一段、二段加氢脱硫单元的循环氢纯度均提高了2个百分点以上,氢耗降低了300 m^(3)/h以上,如此便有效保证二段加氢脱硫单元重汽油产品中硫含量不大于10μg/g的指标要求。

In order to produce vehicle gasoline to meet National standardⅤ/Ⅵ,especially along with its sulfur content under control,the second-stage hydrodesulfurization device and the relevant matching circulating hydrogen desulfurization system were added to the 1.8 Mt/a FCC gasoline hydrodesulfurization unit of Lanzhou Petrochemical Company,PetroChina,then the corresponding countermeasures were comprehensively implemented,in view of the problems during operation such as the poor delivery of rich amine liquids,the oil&hydrocarbon in rich amine liquids and the false indication of liquid level of desulfurization towers.The results showed that:The recycle hydrogen desulfurization system not only effectively removed the H2S generated from hydrodesulfurization reaction,and reduced the H2S content in recycle hydrogen,meanwhile inhibited the generation of mercaptan,but also played an important role in improving the purity of circulating hydrogen and the desulfurization rate of the units,and reducing the hydrogen consumption of the units and the research octane number(RON)loss of gasoline.By regulating and reducing the H2S content of circulating hydrogen from 100μg/g to50μg/g,meanwhile when the reaction temperature of the first&second stage hydrodesulfurization unit both were at 248℃,the desulfurization rate of the first&second stage hydrodesulfurization unit increased by 6,4 percentage points,respectively;When the sulfur content of heavy gasoline products in the first&second stage hydrodesulfurization units was 40,9μg/g respectively,the reaction temperature,mercaptan content of heavy gasoline and gasoline RON loss of the first stage&second stage hydrodesulfurization units corresponding decreased by 4,4℃,3,2μg/g,0.3,0.4 units,respectively;Under the condition that the processing capacity of the first&second stage hydrodesulfurization units both was at 175 t/h,the circulating hydrogen purity of the first&second stage hydrodesulfurization units both increased by more than 2 percentage points,and their hydrogen consumption both reduced by more than 300 m^(3)/h,which could effectively ensure that the sulfur content of the heavy gasoline of the secondstage hydrodesulfurization unit was not more than that control index of 10μg/g。