Simulation And Optimization Of Atmospheric Distillation System

In the petroleum refining industry,atmospheric and vacuum distillation is the first process of crude oil processing,and it is mainly for the initial processing of crude oil,distillation of low-boiling gasoline,kerosene,diesel and other components.It has a large amount of processing and high energy consumption,and its energy consumption accounts for about 20%~30% of the total energy consumption in refinery.The products of crude oil distillation are all high value-added,such as the gasoline,kerosene,diesel etc.The product benefits is very high.Therefore,it is of great significance to optimize the product benefits and energy consumption of crude oil distillation units.The crude oil distillation unit consists of an atmospheric tower and a vacuum tower.This paper mainly studies the atmospheric tower.This paper mainly includes the following contents:(1)The research background and significance of the atmospheric distillation system are elaborated.The process flow of the primary distillation tower and the atmospheric tower is introduced.(2)According to a large petrochemical company's atmospheric distillation unit nearterm operating condition data and operating parameters,it is simulated and analyzed by using Aspen Plus software.The simulation results are consistent with the actual operating conditions,laying a solid foundation for follow-up optimization work.(3)The energy consumption of crude oil distillation unit is analyzed using exergy theory to find out the exergy loss in the unit.As for the midpiece cycle of atmospheric distillation unit,the more low temperature energy is used,the process exergy loss is bigger and the more high temperature energy is used,the process exergy loss is less.According to this law,the maximum proportion of heat transfer in the second cycle is set as the energy optimization goal.(4)In order to optimize the product benefits and the use of exergy in atmospheric distillation unit,sensitivity analysis is used to filter out the decision variables.Total ten independently regulated variables are determined as optimization variables,such as,the yield,feed temperature and steam intake of atmospheric distillation unit.(5)Based on accurate simulation results,the quality process indicators of each product are used as constraints.Step-by-step optimization model in which product benefits is firstly optimized,and then energy consumption is optimized,is set up.Lineup Competition Algorithm is used to search the optimization model on Matlab-Aspen Plus optimization platform.The operating parameters of the atmospheric tower with the maximum income and the lowest energy consumption are acquired.After optimizing the operation,the enterprise can increase the output value of 89.88 million yuan per year,and the total heat taken in the middle of the cycle increases by 1.90 MW,which saves a lot of energy.(6)Aspen Energy Analyzer is applied to analyze the existing heat exchanger network.Since pinch point is given,the minimum utility targets are determined.Heat exchanger network optimization goals including minimum annual cost and lowest equipment cost are proposed.A variety of recommendations are acquired using the software,the best recommended program is selected with the lowest total annual cost as the main goal.