Simulation Study Of Fluid Catalytic Cracking Unit And Optimization Of The Energy System

With the growing international demand for energy, requirements for high-quality energy are also increasingly more stringent. Energy saving has become a great issue in government and enterprises while innovating high quality energy production process. FCC is the core of the secondary processing of crude oil, the main process of lightening heavy oil. In China, the catalytic cracking process still exists a large gap compared with advanced level, its energy consumption is huge and accounts for about one third of the entire refining industry, which led to high cost of production of the FCC. Meanwhile, due to recent heavy oil catalytic cracking industrial demand increasing year by year, and decreasing the energy consumption is extremely urgent, so petrochemical and refinery enterprises especially FCC unit can be effectively in reducing energy consumption has become an important issue.A FCC unit of 1.4Mt/a in a Chinese refinery is taking as a study background, and its materials, products, process flow etc. are introduced briefly. According to the calibration data collected from the unit, including equipment operating parameters and properties of process flow etc., it can adopt the corresponding simulation strategy of FCC unit, such as reasonable selection of thermodynamic method, composition fitting of reaction oil- gas, selection criteria of segmented tray efficiency etc.. Then using process simulation software Aspen Plus to do the FCC unit main fractionator and absorption stabilization system modeling. Compared the simulation results with the calibration values, it can determine the error is in a reasonable range and the simulation results is reliable for the later energy system optimization.Using typical energy analysis and optimization measures to analyze and optimize the FCC unit. Using three- link model do the process energy analysis and evaluation, it concludes that the current FCC unit has adopted advanced and reliable technology to ensure the rationality of heat exchange in the unit, reduce the using of utilities, recover the low- temperature heat in the unit by using recycled water and demineralized water. The paper is mainly based on the pinch technology to optimize the heat exchange matches. It can obtain the minimum utilities targets by analyzing the stream data extracted from Aspen Energy Analyzer. In order to optimize the heat exchange network and reduce energy consumption, it can eliminate the cross pinch point heat exchange and disconnect the heat loop. Use Aspen Exchanger Design and Rating to rate or design the heat exchanger which has stream data changes, and do the energy consumption and economic analysis of the modified heat exchange network. The result shows that the retrofit can achieve good economic benefits and the returns on investment is considerable. Results of this study illustrate the importance of pinch technology used in the optimization of FCC energy systems. Either from its energy saving or improving economic efficiency, it always has a certain theoretical and practical guidance value in retrofit and optimization of the same type devices.