The Evaluation Of FCC Gasoline Hydrotreating Catalysts

Gasoline and diesel oil are principal forms of irrecyclable liquid fuel. New national standard for fuel oil will soon be publicized, which intends to control the content of sulfur compounds and olefin. The harmful substance left by the burning of sulfur and olefin contained in gasoline has become one of major elements of environmental pollution. The catalytically cracked gasoline constitutes 80 % of Chinese gasoline product, and furthermore 90 % of sulfur and 90 % of olefin of finished gasoline also come from the catalytically cracked gasoline. Therefore how to reduce the content of sulfur and olefin in FCC gasoline proves to be the key problem for improving the quality of gasoline.It has been proved that if the sulfur content of gasoline drops from 450μg/g to 50μg/g, the content of SO2 in end gas would accordingly be reduced by 90 % t, NOx 9 %, CO 19 % and HC 18 %. On average the harmful substance is reduced by 16%.Under low temperature the olefin in gasoline is subject to oxidization and become sticky, consequently causing the blockage of pipeline and spray nozzle; while under high temperature the olefin is liable to carbonize and produces sediment in the engine which greatly influences the function of the automobile. The volatilized olefin in atmosphere will accelerate the formation of ozone in convective zone and cause light chemical fog. The research has indicated that if the olefin content drops from 20 % to 5 %, the NOx in end gas would be reduced by 9 %, HC 6 %, harmful substance 30 % and ozone in convective zone 70 %.In this sense, to reduce the content of sulfur and olefin in FCC gasoline turns to be an important method for improving quality of atmosphere and environmental protection. The current industrial technique for removal of organic sulfur compounds from fuel and reducing the content of olefin hydrocarbon.is hydrodesulfurization by selecting appropriate catalyst.This dissertation initially analyzes the characteristics of different crude oil and the composition and distribution of sulfur and olefin in FCC gasoline by different catalytic cracking processes then make a comparison among the existing techniques...