Application Of Process Simulation Technique On The Atmospheric And Vacuum Distillation Unit

Process simulation technology is based on the mechanism of unit operation, adopt a mathematical method to describe the chemical process. Through the application of computer aids to carry out the process of mass balance, heat balance and equilibrium, so as to make environmental and economic evaluation. It is may be the most convenient,saving and safe way to understand the change of real process.Process simulation technology provides a powerful tool for engineering design, process analysis, development of new technology. We have not only the means to determine the merits of a device from the perspective of the whole system, also can provide reliable prediction analysis for the develop of new processes.These measures will help people to improve efficiency and decision-making more scientific.Using computer to simulate and optimizate the refinery and chemical plant, make them at the best operating conditions, so that improve the economic efficiency of production. It is one of high-tech both at home and abroad in efforts to develop. Atmospheric and vacuum distillation unit is the first refinery processes of crude oil, known as the "leading" of refining business and in an important position of petrochemical enterprises.The increase of pull rate efficiency is not only reflected in the device,more importantly, is reflected in the lower reaches of the second and third processing devices and products,blending and the efficiency of petrochemical joint ventures.Therefore, the use of process simulation technology to simulate and optimize the operation of atmospheric and vacuum distillation unit in the best operating conditions, has increasingly become a domestic and international attention and study. In this paper, using process simulation software UniSim Design and PR thermodynamic equation to simulate a 6 million tons/year of crude oil distillation unit. Main tasks are as follows:Firstly, cut crude true boiling point distillation data of crude oil to a certain number of virtual components, and then select the appropriate initial boiling tower, crude distillation, vacuum tower of the unit module and convergence method, provides simulation model and process parameters of the tower, adopted sequential modular approach to simulate one by one element. Get the tower key indicators of flow and temperature consistent with the actual conditions, the simulation results show that the chemical processes of atmospheric and vacuum devices simulate the real reflection of the device operating conditions, make the foundation for the process of optimization.According to the atmospheric and vacuum distillation process simulation results, using the "Pinch Analysis" to optimizate the heat exchanger network of atmospheric and vacuum distillation unit. After improvements,the final heat transfer temperature of the topped crude oil increased from 289℃up to 298℃,the final temperature of heat exchanger increased 9℃, lowered the heat load of atmospheric pressure furnace and saved the consumption standard fuel.