The Reformation Of Gas Oil Hydrogenation And Catalytic Cracking Combination Process Aiming At Improving The Gasoline-diesel Ratio

With the development of domestic economy,the demand for gasoline is improving and that for diesel is decreasing.Refineries should adapt to the market variation and regulate the unit structure.Gasoline need to be increased and diesel need to be reduced.The gasoline-diesel ratio need to be increased.In order to break through the bottleneck of the poor product distribution and low gasoline-diesel ratio of the original gas oil hydrogenation and FCC combination process,a technical reform has been carried out in Sinopec Luoyang Company.In this paper,based on this project,a reformation on improving the gasoline-diesel ratio based on gas oil hydrogenation and FCC combination process was carried out.Some problems in the gas oil hydrogenation and FCC combination process were analyzed,and the results showed that the product distribution of FCC unit was not satisfying.The gasoline-diesel ratio was low(2.15),meanwhile the sulfur and nitrogen of diesel production were high and the cetane number was low.It must undergo secondary processing or blending with high quality diesel fuel.In order to break the bottleneck of the low gasoline-diesel ratio for the current combination process,LCO hydrogenation and FCC combination process was built.In this new combination process,the FCC diesel firstly goes to the gas oil hydrogenation unit,then the product returns to FCC unit with the hydrofining diesel.Based on this,this paper built a kinetic model using the structure-oriented lumped method to simulate the new LCO hydrogenation and FCC combination process.The simulation results showed that after the new technology was adopted,the gasoline yield,diesel yield and the gasoline-diesel ratio were increased by 2.8%,8%and 1.3,respectively.FCC product distribution was optimized greatly and gasoline-diesel ratio was increased.This new process could get a very good profit.Finally,the effects using the LCO hydrogenation and FCC combination process were examined.For the new technology,the gasoline yield,diesel yield and the gasoline-diesel ratio were increased by 2.4%,8.39%and 1.39(increased from 2.15 to 3.54),respectively.With the FCC feed rate of 173 t/h and the annual processing time of 8400h,the gasoline production was increased by 34,800 t/year,while diesel decreased by 121,800t/year.At the same time,the properties of catalytic gasoline and diesel were improved notably.The RON of gasoline increased from 90.4 to 91.1 and the density of catalytic diesel decreased.The simulation results were consistent with the industrial data perfectly.The goal of the combination technology renovation has been accomplished.This modification has gained huge benefits for Sinopec Luoyang Company.