Research Of Deep Desulphurization In FCC Gasoline With Oxidation And Extraction

In this dissertation, the oxidating reaction factors (the amount of hydrogen peroxide, the volume ratio of the hydrogen peroxide to acetic acid, reaction temperature, the reaction time) are discussed with the means of perpendicularity. The result showed that the reaction temperature has the largest effect to the rate of sweeting and yield, successively the volume percent content of the hydrogen peroxide, the proportion of the hydrogen peroxide and acetic acid, and the last is the reaction time. On the base, all factors are discussed one after another. The effect of reaction temperature is first upwards and then descent, but if the temperature is too high in specified reaction time, it affected the yield. Hydrogen peroxide has selective oxidation, quantitative hydrogen peroxide accelerates the reaction, while over-dose hydrogen peroxide oxidate those unsaturated hydrocarbons, so the amount of hydrogen peroxide must be restricted. A bit of over-dose acetic acid will speedup the formation of super-oxygen ethanoic acid,thereby accelerated the generation of oxidant reaction. The successive optimum term is: reaction temperature 50℃, the content of hydrogen peroxide 7%, the volume ratio of the hydrogen peroxide to acetic acid 2:3 and the reaction time 40min. The rate of desulphurization in FCC gasoline is 56.41%, the yield of gasoline is 95.43%, the content of sulfur dropped from 197.26μg/g to 111.27μg/g in the optimum condition. In order to remove sulfide thoroughly further, the extraction is used. The NMP of 95% used as extracting agent, the ratio of agent to the quantity of gasoline, extraction temperature, extraction time, subsiding time are researched. Through the experiment, extraction temperature and subsiding time have no much affect to the rate of desulphurization, but to the yield, they have much. If the extraction temperature is too high and subsiding time long, they accelerate the volatilization of refined gasoline. The yield dropped obviously. The ratio of agent to gasoline and extraction time can clearly affect to the rate of desulphurization. Increasing the ratio of agent to the quantity of gasoline, enlarging extraction time, the sulfur can be removed thoroughly, while the yield dropped rapidly. On the basis of these datas, the best extraction condition is: the volume ratio of agent to gasoline is 2:1, extraction time 20min, atmospheric temperature and subsiding time 20min.After oxidated and extracted, the sulfur in FCC gasoline descends from 197.26μg/g to 54.96μg/g, near 50μg/g (the standards of Europe IV desulphurization), and the rate of desulphurization is 93.73%, the yield is 93.58%.