Establishment And Application Study Of FCC Process Simulation Model Based On Aspen Plus

This assay mainly analyzed the abnormal operating conditions of the fractional system and absorption stability system of 0.8Mt/a fluid catalytic cracking unit from a petrochemical company in 2016,and proposing solutions for these abnormal conditions.First,In the second chapter,the Aspen Plus process simulation software was used to establish the model for fractionating system and verify its applicability.Then process simulation software was used to simulate and analyze the process flow.According to the problems of the device,the relevant process parameters can be reasonably adjusted to solve the device problem.The abnormal working condition?of the device is that the pump in middle part of the distillation column can't draw sdandard liquid from the mid extracted trays.In the third chapter,using the Cup-Tower to extract the trays for hydraulic analysis,it was found that the out of liquid phenomenon of the mid extracted trays is serious.Analyzed with analog values and calibration values of Aspen Plus,it was found excessive slurry circulation in the fractionating tower that causes excessive proportion of slurry heating.Therefore,the circulation volume of the slurry is reduced from 181.5 t/h to 141.5t/h.In order to balance the overall heating effect of the fractionating tower,the top circulation amount is increased from 115 t/h to 145t/h to optimize the proportion of heat taken and eliminate the out of liquid phenomenon.The abnormal working condition?of the device was that the liquid level of the oil refining tank is plummeted,and the liquid level drops below 20%?normally in20%-60%?.After analysis,In the fourth chapter,the hydraulics of the fractionating tower are analyzed.It was found that the liquid phase flow rate of the pump trays at the pumping plate was too low and the circulation flow at the top was increased.By increasing the top circulation flow from 115 t/h to 170 t/h,the optimal adjustment is140t/h,the level of the back refining tank reached 30%to normal level.The abnormal condition III of the device is the phenomenon that the percentage of C₃⁺components in the dry gas of the absorption and stabilization system exceeds the standard.The laboratory test analysis data C₃⁺component percentage is 3.851%which exceeds the normal working condition 2%or less.In the fifth chapter,by lowing the temperature of the crude gasoline into the tower from 40°C to 38°C,and adjusting the temperature of added absorbent into the tower and the amount from 35°C and 35.2t/h to32°C and 37.8t/h,the temperature and the amount of the lean oil absorption into the towers from 40°C and 27.7t/h to 36°C and 32.7t/h,the percentage of C₃⁺components was reduced to 1.49%from 3.851% to achieve the optimization goal.