Study on a New Extractive Dividing Wall Column for Dimethyl Carbonate and Methanol Separation

Benzyl methyl ether (BME) was developed as an extractant for separating dimethyl carbonate (DMC) from methanol (ME). The study evaluated the performance of extractive distillation columns (EDWC) with single and two walls through experiments and simulations. The two-wall EDWC demonstrated superior separation efficiency, achieving ME and DMC purities above 99.9% under optimal conditions: solvent-to-feed ratio of 8, 45 theoretical stages, atmospheric pressure, extraction section/azeotropic separation section sideline at the 34th plate, azeotropic separation/DMC purification section sideline at the 20th plate, 12 theoretical stages in the common rectification section, and vapor split ratios of 0.42 (extraction section/azeotropic separation section) and 0.27 (azeotropic separation/DMC purification section). Experimental results aligned well with the simulations. The EDWC with two walls, which integrates the extraction section, azeotropic separation section, and DMC purification section with shared reboiler heating, offers significant potential to replace current DMC/ME separation processes and reduce production costs.