Optimization Of Scheduling And Heat Integration In Batch Process Based On Genetic Algorithms

The flexibility and adaptability of batch processes are essential to produce highvalue added materials such as agrochemicals,pharmaceuticals,foods and fine and specialty chemicals,the demand for which has risen in recent decades.Heat integration is a hot topic of batch chemical design and optimization,among which the simultaneous optimization of scheduling and heat integration can realize the best use of resources in the system,which is in line with the development of the chemical industry in this century.However,due to the complexity of the batch process,the optimal problem involves numerical related parameters,which may leads to the problem of combination explosion.Besides,there are some extraordinary operations in batch process,such as multi-period product and some units the can perform multiple tasks.Thus the problem is easy to fall into local optimum or no solution conditions.In this paper,several kinds of batch plants is optimized by modeling software.The main contents are as follows:(1)The characteristics of batch process are analyzed,and the research progress and research hotpots are summarized.Simultaneous optimization of both scheduling and heat integration can lead to global optimal design,which is difficult to reach.In order to solve the optimization problem efficiently,an Inner-Outer Loop Simultaneous Optimization method(IOLSOM)based on genetic algorithms is presented,which decomposed the problem into two interrelated modules so as to reduce the difficulty of solving.(2)On the basis of genetic algorithms,the mathematical model of scheduling and heat integration in batch process is established to solve the problem.A general solution strategy and related mathematical model are presented to optimize some typical batch plants.The efficiency of chemical systems are improved by integrate thermal energy: In typical multi-product batch plant,the makespan within a production cycle can be shorted by translating the type of storage from ZW to UIS.By considering the heat integration,the system energy is increased by 2.01 times and the utilities are saved by 2446 kJ.In multi-purposed plant,the system energy is increased by 2.15 times and the utilities are saved by 3830 kJ.(3)According to the characteristics of complex batch chemical plants,a mathematical model of scheduling and heat integration is established for the scheduling and heat integration of complex multi-purpose plants with multiple periods.To demonstrate multi-period production of complex batch plant,the concept of ‘Pseudo Period' is proposed to code the chromosome.Rescheduling the process with multiperiod can shorten the makespan and increase production efficiency,so as to effectively improve the efficiency of the process.