Energy-saving investigation for diethyl carbonate synthesis through the reactive dividing wall column combining the vapor recompression heat pump or different pressure thermally coupled technique

Abstract

The design of the diethyl carbonate (DEC) production process has received much attention due to its key role as the oxygenated gasoline additive with much fewer environmental and health issues than methyl tert-butyl ether. In this study, two configurations including vapor recompression heat pump (VRHP)-reactive dividing wall column (RDWC) with or without the splitting top stream are investigated for DEC production to screen out the best VRHP sequence. Furthermore, a novel alternative approach of different pressure thermally coupled-RDWC (DPTC-RDWC) is comparatively proposed to achieve less capital and energy cost. The effects of pressure within stripping section of the RDWC on total annualized cost (TAC) and the temperature difference between the condenser and reboiler are studied. The results illustrate that the proposed optimum process produces DEC production with the purity of 99.8 mol% and significant reduction of TAC is achieved by 20.52% with 10 years payback period. Apart from that, carbon dioxide emission of the process is decreased by 33.74% compared to that through conventional RDWC.