(82b) Improved Energy Efficiency and CO2 Emission Reduction in Dimethyl Carbonate Reactive Distillation System through Various Heat Integration Methods

In this study, we propose enhanced energy-efficient design alternatives for the production of dimethyl carbonate (DMC) through the combination of various heat integration methods in reactive and pressure-swing distillation (PSD) columns. The proposed hybrid heat-integrated designs were based on internal and external heat integration between the columns with a vapor recompression heat pump (VRHP). The conventional 3-column DMC production sequence and the hybrid heat integration sequences were compared while maintaining high product purity of 99.5%. Our findings show that the combined sequence of internal and external heat integration led to a significant cost saving of 30.28% by eliminating the low-pressure (LP) column reboiler. The external heat integration combined with VRHP fully eliminated the heat duty of the high-pressure (HP) column condenser and the LP column reboiler, which showed 38.33% energy savings and a 37.5% reduction in CO2 emissions. Furthermore, the two hybrid sequences with external heat integration outperformed the internal heat integration with VRHP in terms of energy, economic efficiency and CO2 emissions due to a significant reduction in the reflux flow rate of the HP column and the reboil flow rate of the LP column.