Energy Integration And Flexible Operation Of The Integrated System Of Chemical Production

MDI integrated project is known for its large scale, long products line and complexprocess. With the potential of energy saving, the heat exchanger network synthesis andoptimization as well as the cascaded utilization of energy in this project will increase theenergy utilization rate and set a model in chemical industry.In this article, aiming to achieve the cascaded utilization of energy in this project,following contents are included. Take methanol plant for example. Analyze the energycascade utilization and heat exchanger network optimization and synthesis of methanolplant.Based on the process streams data and literature information, the whole process ofmethanol plant is simulated with ASPEN PLUS. In this way the heat duty of main heattransfer units and the data of streams in and out the energy equipments are obtained.Then these units are transferred into corresponding hot streams and cold streams. Withthe pinch technology and aspen energy analyzer to match hot streams with cold streams.Then obtain a heat network with the lowest energy consumption. Empirical method andheat exchanger network synthesis help us gain a satisfying heat exchanger plan.A global sensitivity analysis method based on variance—Sobol’ method isintroduced for the analysis of heat exchange network. The paper narrates the principleof Sobol’ method and analyzes the realization of numerical simulation that influentialfactors of heat exchange network sensitivity. Assuming each stream’s temperaturefluctuations boundary value is15%and the flow rate of the heat capacity boundaryvalue is10%, when using the Sobol’ method. It calculates the boundary valuefluctuations in the calculation of various factors with Latin method. By the analysis ofresults, it determines the three laws with the global sensitivity analysis. Draw the initialtemperature of the reaction gas cooler H1greatest impact on the operating performanceof the heat exchanger network. The initial temperature value of the reactive gas coolerH1interacts with other factors.It elaborates the reason of heat exchanger network flexibility analysis. It gets themonotonic analysis of the factors with the heat exchanger network and the values oflogistics outlet temperature fluctuation range of the two boundary limit. In this paper,the methanol process flexibility analysis mathematical model is established and theobjective function and the constraints are determined. It Solves the NLP model with LINGO software. Comparing with the original sum of the heat exchanger area, theanalog of the heat exchanger areas reduce the proportion of1.62%, and the reduction ofthe total area is105.44m2after the summation.The heat exchanger network design margin and the thermal fouling of the heatexchanger after the long-running impact on the efficiency of the heat exchanger areanalyzed. The setting principles of bypasses with the heat exchanger network areanalyzed. It establishes the bypass mathematical model and determines the location ofbypass of the methanol plant heat exchanger network. The pressurized the towercondenser H2and atmospheric tower the H8two streams of the condenser heatexchanger of the shares on the bypass, the bypass opening degree were0.35and0.32.