Optimization Tactics Based On Exergy Load Distribution Method

Integrated production has come true in modern industrial process, and the equipments are increasingly large and complicated, which require the entire equipment even a joint enterprise to achieve optimal design, optimal control and optimal management. So evaluating the energy consumption in process and enhancing the thermodynamic performance of process are particularly important.Exergy optimization of large chemical processes can be difficult because the local efficiencies of subsystems are interdependent in a way which was heretofore difficult to anticipate. The impact of exergy efficiencies of subsystems on overall exergy efficiency of the whole system is uncertain. So it's necessary to develop a universal formula which is independent of the structure of a system and relate the total exergy efficiency of any system to the efficiencies of its subsystems. This paper studied the application of the exergy load distribution method for the thermodynamic optimization of process of manufacturing ethylene from ethanol to obtain the optimal thermodynamic structure of the process. The following points are emphasized:1. The operation models of the existing ethylene production process by ethanol dehydration were set up for the simulation, and the thermodynamic model was aslo determined.2. The existing ethylene production process by ethanol dehydration was simulated by making use of the chemical engineering simulation software ASPEN PLUS, and the exergy analysis was carried out based on the simulation results. The obtained exergy efficiency and other parameters supplied reference to the optimization of existing process and simulation of improved processes.3. The improved processes were put forward according to exergy load distribution method. simulation of these processes were carried out by ASPEN PLUS, then exergy analysis was done.4. This paper studied the application of exergy load distribution method for the process optimization of chemical process which contains a heat exchanger network; For the chemical process system contained multi-effective distillation, the way of analysis with exergy load distribution method was also studied. 5. On the basis of total exergy efficiency of whole system, the simulation results of existing process and improved cases 1 and 2 showed that the case 1 was better. The way to analyze multi-effective distillation can affect the distribution of exergy load observably; The heat exchanger network was treated as a single operation, which greatly simplified the graphical representation of the exergy analysis and necessary computations.