Design,Energy Saving And Control Strategy Research On Synthesis Of Isopropyl Acetate Based On Reactive Distillation

In view of the low product purity and high energy consumption of the synthesis of isopropyl acetate through the conventional reactive distillation process（CRD）,this work designed a different pressure thermally coupled reactive distillation process（DPTCRD）and a heat pump reactive distillation process（HPRD）for the synthesis of isopropyl acetate through the esterification of acetic acid and isopropanol,the advantages and disadvantages of these two energy-saving reactive distillation processes over the conventional reactive distillation process are investigated.Firstly,the steady state models for the CRD,DPTCRD and HPRD were established by aspen plus respectively,and the process parameters were optimized independently.Secondly,the equipment investment and operation cost of CRD,DPTCRD and HPRD are calculated respectively by employing the objective function of total annual cost（TAC）,the optimal process was determined after evaluating the product purities,energy requirements and TACs of different reactive distillation processes.Finally,the control strategy was investigated to obtain a feasible control scheme for the selected optimal reactive distillation process.The results show that the isopropyl acetate product purities synthesized through the CRD,DPTCRD and HPRD processes are 99.98%,99.7%and 99.971%in mass fraction,respectively,which all meet the design specification of product purity（99.5%in mass fraction）.The amount of energy saving of the DPTCRD process equals 2188.98 kW while the HPRD process equals1934.89 kW when the isopropanol feed flowrate is kept at 50 kmol/h.The investments of CRD,DPTCRD and HPRD processes are 1441.03$1000 year^-1,1665.11$1000 year^-1 and 1754.53$1000 year^-1,respectively.The TAC of CRD process is 1031.15$1000 year^-1,thanks to the introduction of energy saving systems,the TACs of DPTCRD and HPRD processes decreased by 17.98%and 15.08%respectively compared with the conventional reactive distillation process.The different pressure thermally coupled reactive distillation process is proved to be the economically optimal process for the synthesis of isopropyl acetate.For the DPTCRD process with the best economic performance,two sets of different control structures were firstly established and then the control performances were investigated.The results show that the top reflux of the product treating column can be used to control the sensitive tray temperature,and with the feedforward controller（the tario of heat duty to feeding flowrate of product treating column）installed,the control scheme CS2 can deal well with the feed flowrate and composition disturbances,thus demonstrate good performances...