Simulation And Optimization Of 150kt/a Refinery Gas Fractionation Process And Utilization Of Low-temperature Heat

With the development of petrochemical industry,refinery gas has become a valuable raw chemical material.Products with high value-added can be obtained by separating refinery gas and used as the raw materials for the next step production.Gas fractionation is a mature fractionation technology.But it has some drawbacks such as higher energy consumption,lower yield of product,and unreasonable heat matching.In this paper,150kt/a gas fractionation unit in refinery was build using refinery gas from reforming process and atmospheric and vacuum distillation process based on the problems on the traditional fractionation technolog mentioned above.A four-tower process for separation of refinery gas was explored in order to realize the aim of low energy consumption,high yield,and effective heat matching.The steady state model is established by using HYSYS process simulation technology.The process parameter was opitimized and thus realizing the purpose of energy saving,efficiency increases and yield maximizing.At the same time,suitable low temperature heat source for the gas fractionation unit was found on the basis of the heat balance and this process made the energy consumption and device investment decrease.Thus,maximum economic benefit will be achieved for the enterprise.The whole process of gas separation unit was simulated with HYSYS software.The simulation result was analyzed through sensitivity and the optimal operation parameters of the fractionator were determined under the premise of ensuring product yield and index,That is to say,the optimal feed heat condition,the position of the feed plate,the reflux ratio and the operation pressure,etc,were confirmed based on meeting the requirements of the products separation.At last,the process flow chart(PFD)and the logistics data sheet are drawn,and the material balance is calculated.Calculation and selection of tower body for depropanizator,deethanizer,depentanizer,butane tower and its tray were completed,respectively.The equipment sheet was determined.In addition,the high efficiency float valve tray is used in the fractionator,and the tray parameters are calculated and the corresponding calculation and selection for the equipment were finished.The energy consumption and its consumption level of the gas fractionation unit in steam,circulating water and power were calculated.Effective energy consumption matching for gas fractionation unit was realized by combining the devicewith FCC unit.The detailed engineering design was performed based on the results of process simulation according to the equipment and piping layout principle.The pipeline and instrument flow chart,equipment layout and piping layout diagram were completed.