Multi-objective optimization involving cost and control properties in reactive distillation processes to produce diphenyl carbonate

摘要

Polycarbonate has a very extensive commercial application thanks to its multiple physical properties. The environmental problems associated with the conventional process to obtain polycarbonate by the phosgene route has stimulated the research of intensified schemes as is the case of the reactive distillation for the synthesis of Diphenyl Carbonate (DPC). These intensified processes are complex in their structure because of the several degrees of freedom and are subject to be optimized in terms of crucial criteria such as the cost and the control properties. This work presents the multi-objective optimization involving cost and control properties of four intensified systems configurations to produce DPC: a conventional reactive distillation (CRD), a thermally coupled reactive distillation (TCRD), and two novel configurations which uses vapor recompression technology, a reactive distillation with heat integration (RDHI) through vapor recompression, and a reactive distillation with thermally coupling and heat integration (THRD) through vapor recompression. The results of the multi-objective optimization show that the tray holdups and diameter values of the columns strongly influence the control properties; thus, for large values of the tray holdups and diameters, the control properties were better. The control properties also were influenced by the presence of the interlinking streams in the reactive and separation columns, in particular, the presence of one interlinking stream tend to favor the control properties of a configuration. To close it is important to remark that the TCRD configuration was the most attractive arrangement to be implemented to produce DPC, mainly because the optimized designs showed the best control properties, and also the optimized designs achieved significant energy savings because they did not require electric power.