Operation Optimization And Energy Analysis Of 140×10~4 T/a Fluid Catalytic Cracking Unit

With the rapid development of society,the consumption of resource is increasing rapidly so that the efficient utilization of energy has become the focus of current society,all levels of government and enterprises.In order to make maximize use of resources in the refining industry,Fluid Catalytic Cracking Unit(FCCU)was usually seen as secondary process of goudron,desphalted oil and tail oil to achieve the purpose of high efficiency utilization.So far,there was still a gap on energy consumption and operation cost of the FCC technology between the advanced world level and domestic level.Therefore,it is extremely important to analyze the energy utilization scientifically and reasonably,reduce the energy consumption and enhance the operation level of FCCU.A FCCU of 1.4 Mt/a in a refinery of Shaanxi province has been taken as an object of study.The process simulation and optimization model were established for the fractionation and absorption-stabilization system of FCCU by simulation software Aspen HYSYS.And energy consumption was analyzed by Aspen Energy Analyzer.Concrete results are as follows:(1)It was simulated for the fractionation and absorption-stabilization system of FCCU by simulation software Aspen HYSYS.The simulation result was able to better reflect the actual operation of the device,which provides a reliably theoretical basis for the follow-up optimization.(2)Based on the model validation,the fractionation and absorption stabilization system of FCCU were optimized.First,the effect of the reflux ratio was analyzed on the quality of overhead product and light diesel of the side-line extraction.The influence of overhead and medium circulation volume was obtained on the endpoint of gasoline and 5%point of light diesel.Secondly,the property of the absorbent,the position and drew-out quantity of side-line in the stabilizer was researched on the effect of the content of C3+ in poor gas and dry gas.Eventually,the influence of main system operating parameters,such as temperature and pressure of the stripper's bottom,feed temperature of stabilizer,were analyzed on the absorption effect and product quality,in order to obtain the optimization of the absorption and desorption.(3)Based on the simulation and optimization research,the pinch technology theory has been used to analyze the heat exchanger network of the fractionation and absorption-stabilization system in the FCCU by software Aspen Energy Analyzer.The unreasonable heat transfer between cold stream and hot stream was identified and the corresponding optimization scheme of heat exchanger network was proposed.Secondly,the adjustment and selection design of the adjustment and new heat exchanger in the heat exchanger network process were carried out.Finally,the feasibility of optimization scheme had evaluated in respect of the equipment investment and annual economic benefits.The results indicated that the optimization improvement scheme have a sensible economic benefits,a short payback period.and a actual application value.