Operation Optimization Of The Fractionation System Of Kerosene & Diesel Hydrocracking Unit Based On Process Simulation Technology

Hydrocracking of coal and diesel is an important unit in the process of crude oil secondary refining.After the high pressure hydrodesulfurization,denitrification,refining,cracking and other reactions,the straight-run coal and diesel finally transform into aviation kerosene,diesel fuel products in line with national environmental protection requirements.Meanwhile,the system provides high quality light or heavy naphtha raw material for ethylene and reforming unit.Its fractionation system is responsible for separating hydrogenation reaction products into liquefied petroleum gas,light naphtha,heavy naphtha,aviation kerosene and diesel.Therefore,finding the optimal operation parameters without changing the equipment and the technological process,to guide the operation,has been highly concerned by the chemical industry enterprises.In order to solve the problems,a research method of multi-variable,single-objective and multi-objective automatic operation optimization of chemical unit based on process simulation data and multi-software integration has been established It uses the OLE function provided by PRO/II software,through Excel-VBA programming,embeds genetic algorithm(GA and NSGA-II),so as to integrate the function of powerful data calculation,data storage,friendly interface,powerful simulation and global-fast optimization.And then,to realize one-key automatic operation optimization,to quickly find the optimal operating parameters of the unit under a specific target,on the interface of Excel.Because the method is driven by simulation data and software integration,it is suitable for the operation optimization research of all simulated chemical units.Finally,the method developed in this paper is applied to the operation optimization research of the fractionation system of a 3.6 million tons/year coal and diesel hydro cracking unit of CNOOC,which is based on the top pressure of the main fractionation tower,the first medium flow rate,the second medium flow rate,and the naphtha fractionation tower.The 4 variables of the tower top pressure are independently adjustable operating variables.The dry point of heavy naphtha,the initial boiling point and dry point of jet fuel,the initial boiling point of diesel oil,the tower pressure and the rated flow rate of the reflux pump are used as constraints.Single-objective and multi-objective optimizations are carried out for four working conditions of minimum unit energy consumption,maximum unit income,minimum unit energy consumption and maximum light oil yield of the system.The calculation results show that all the four optimization schemes can find the optimal solution automatically.Among which,the exergy loss reduces 28.55% under the project of minimum procedural exergy loss;the energy consumption reduces 23.48% under the project of Minimum unit energy consumption;the unit revenue increase 0.09%;the increase rate is 5.478 million yuan/year.The results indicate that the operation optimization method based on simulated data developed in this paper is feasible and effective.