Simulation And Optimization Of Atmospheric And Vacuum Distillation Units

The petrochemical enterprise is a very energy consuming enterprise and it is a traditional high energy consumption industry.Atmospheric-vacuum distillation unit is the first step in the process of petroleum processing.The energy consumption is about 1/5 to 1/3 of the whole oil refinery.The process and energy consumption level of crude oil production by atmospheric and vacuum distillation unit have great influence on the investment of equipment and static equipment,maintenance and management of equipment,optimization and energy saving and economic benefit of petrochemical enterprises.The energy consumption level of atmospheric and vacuum distillation units in China is still somewhat different from that of the atmospheric and vacuum distillation units abroad.The energy consumption level of atmospheric and vacuum distillation units in China has considerable potential for energy conservation.The research subject of this project is a 2.3 million tons/year atmospheric-vacuum distillation unit of a refinery.Aspen Plus software is used to establish a process model for atmospheric and vacuum distillation units,and the whole process simulation analysis and process optimization are performed,including three aspects: simulation of flash column and atmospheric and vacuum distillation column,the optimization of the atmospheric distillation column process and the synthesis of the heat exchanger network.(1)Simulation of atmospheric-vacuum distillation unit: According to the boiling point curve of the crude oil and the process parameters of the main equipment,the physical parameters of BK10 were selected and a model was established for the distillation process of the atmospheric and vacuum distillation units.Adjust the parameters so that the simulation results are consistent with the calibration data,which is the basis for the optimization of the atmospheric distillation column.(2)Optimization of the atmospheric and vacuum distillation unit: Based on the simulation results of the atmospheric distillation column,the production flow rate of the side column product of the atmospheric distillation column is adjusted by adjusting ASTM D86 90% distillation temperature of the Changerxian and Changsanxian products,so that the product flow rate is recovered and it is normal.By adjusting the circulating volume of changyizhong and Changerxian to achieve the purpose of adjusting the heating in the middle section of the cycle,the proportion of heat taken in the three mid-cycles is closer to the proportion of empirical heating.Based on the adjustment of circulating heat collection in the middle section of the atmospheric distillation column and production problems of the side-line products,sensitivity analysis was used to find out the relationship between the steam stripping steam flow rate at the bottom of the atmospheric distillation column,the outlet temperature of the atmospheric furnace and ASTM D86 5% distillation temperature of bottom oil.Adjusting the outlet temperature of the atmospheric furnace and the stripping steam flow at the bottom of the atmospheric tower,the pull-out rate is increased by 2.03%.Based on the optimization of the outlet temperature of atmospheric furnace and the steam stripping steam at the bottom of the atmospheric tower,the circulating flow rate and temperature of Changyizhong and Changerzhong is adjusted,which is based on the original design of the atmospheric and vacuum distillation units.Changdingxun,Changyizhong and Changerzhong of the final mid-cycle heat collection ratio is approximately 2:4:4,which is better than the heat ratio of 3:3:4 for engineering experience.(3)Comprehensive optimization of the heat exchange network of the atmospheric and vacuum distillation process: According to the relationship data between the minimum heat transfer temperature difference and operation cost,equipment cost and total cost,the optimal minimum heat transfer temperature difference is selected.The heat exchanger network is analyzed.The heat exchanger passing through the pinch point is found in the heat exchanger network.The heat exchanger E1124 with large energy loss undergoes heat exchange is adjusted and the final preheat temperature of the crude oil has been improved,when atmospheric tower has not been optimized and optimized.(4)By identifying and disconnecting the heat load loop,the heat exchanger E112 and E124 are reduced,and investment is reduced.