Synthesis And Design Of Reactive Dividing-wall Distillation Column With Vapor Recompression Heat Pump

The reactive dividing-wall distillation column(RDWDC)is a very promising technology.It combines the dividing-wall distillation column(DWDC)technology and the reactive distillation column(DWDC)technology.In comparison with conventional two-column reactive distillation,the RDWDC achieves reductions in capital space and capital cost,and reduces energy cost because the RDWDC applys the thermal coupling technology.However,we noticed that heat was conventionally supplied in the reboiler and removed in the condenser,it wasted a lot of energy.According to the characteristics of operation and configuration of the RDWDCs,we proposed to apply vapor recompression heat pump(VRHP)to reuse the latent heat of overhead vapor of the RDWDC to reduce the energy cost of the reactive distillation processes.In current work,we found that combined the VRHP and the RDWDC can enhance the efficiency of energy utilization and improve the steady-state economic benefits.In this paper,we proposed a steady-state design procedure to apply the VRHP to the RDWDC on the basis of the initial configurations of the RDWDC with the VRHP.For the RDWDC,If there are one condenser and two reboilers,three configurations with the VRHP were proposed(the first configuration is applying the latent heat of compressed overhead vapor released to the left-hand side column/right-hand side column of the dividing wall.The second configuration is applying the latent heat of compressed overhead vapor released to the left-hand side column and right-hand side column,simultaneously.The third configuration is applying the latent heat of compressed overhead vapor released to the left-hand side column and right-hand side column by two-stage compressors.).If there are two condensers and one reboiler,three configurations with the VRHP were also proposed(the first configuration is that the heat duty of the compressed vapor from the right-hand side top or the left-hand side top of the RDWDC is released to the right-hand side or the left-hand side column of the dividing wall.The second configuration is that the heat duty of the compressed vapor from the right-hand side top and the left-hand side top of the RDWDC are released to the right-hand side and the left-hand side columns,respectively.The third configuration is that the overhead vapor from the right-hand side top or the left-hand side top is compressed through the one-stage compressor and the two-stage compressor,then provides heat to the right-hand side column or the left-hand side column of the dividing wall).According to the study outcomes,the RDWDC with the VRHP achieved outstanding economic benefits.In a mixed acid esterification reactive system,total annual cost achieved 4.42%/6.50%,10.65%,10.65%reductions for these three configurations respectively.In the system of GLY and HCL reactions,total annual cost achieved 39.68%/13.07%,43.53%,50.62%/16.11%reductions for these three configurations respectively.These outcomes indicated that it could be a favorable option for the reactive separation to apply the VRHP to the RDWDC.