Multiple transesterifications in a reactive dividing wall column integrated with a heat pump

• Published in: The Korean journal of chemical engineering Vol. 36; no. 6; pp. 954 - 964
• Main Authors: Lee, Heecheon, Jang, Wonjoon, Lee, Jae W.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.06.2019; Springer Nature B.V; 한국화학공학회
• Subjects: Biotechnology; Blast furnace gas; Catalysis; Chemistry; Chemistry and Materials Science; Compressed gas; Compressing; Dividing wall columns; Energy consumption; Ethanol; Flow velocity; Gas flow; Heat pumps; Industrial Chemistry/Chemical Engineering; Materials Science; Optimization; Power consumption; Separation Technology; Thermodynamics; 화학공학; Energy Savings; Multiple Reactions; Vapor Recompression Heat Pump; Diethyl Carbonate; Reactive Dividing Wall Column
• ISSN: 0256-1115; 1975-7220
• DOI: 10.1007/s11814-019-0271-5

This study addresses a reactive dividing wall column (RDWC) integrated with a vapor recompression heat pump (VRHP). The reaction applied to the system contains two consecutive transesterifications of dimethyl carbonate (DMC) and ethanol, which yields methanol (MeOH) as a by-product, ethyl methyl carbonate as an intermediate product and diethyl carbonate (DEC) as the final desired product. DEC is the only stable node of the five component reacting mixture. The location of the reaction region and feed stages affects the purity of the top product because the unstable node product is not pure MeOH but DMC-MeOH azeotrope. The VRHP pressurizes the top gas product stream and the compressed gas provides heat to the bottom stream of the ethanol recovery section. The optimization procedure minimizes the power consumption of the compressor with respect to the gas flow rate. The energy consumption in the RDWC integrated with a VRHP is reduced by 32.1% and the total utility cost is also cut by 21.6% compared with the conventional RDWC.