Abstract A hybrid process design based on reactive distillation (RD) combined with pervaporation membrane systems was proposed for the production of ethyl levulinate (LAEE) via esterification. In the proposed hybrid configuration, LAEE is produced from the bottom stream of the RD column while the ethanol/water mixture from the overhead is fed to an additional column. The azeotropic mixture in the overhead of the additional column is separated in the pervaporation unit, and the ethanol-rich stream is recycled to the RD column. An RD-only configuration with excess ethanol reactant was also examined to investigate the benefit of excess ethanol reactant and the azeotrope mixture separation. The proposed RD with pervaporation hybrid configuration provided 61.0% and 71.0% reductions of the total annual cost and energy, respectively, compared to the conventional RD configuration with excess levulinic acid (LA) reactant and 6.0% and 13.0%, respectively, as compared to the conventional RD configuration with excess ethanol reactant. The results demonstrated the advantage of the proposed hybrid RD process using pervaporation for lowering the cost and improving the energy efficiency of LAEE production. Different pervaporation arrangements (such as series and parallel arrangements) were discussed in connection with the two main variables (operating temperature and concentration gradient) affecting the membrane flux. The series arrangement was more suitable for the LAEE hybrid process because the influence of the operating temperature is dominant in this process. Thermal intensification in the RD-pervaporation was also examined for exploring further energy reduction. This thermally coupled RD-pervaporation hybrid configuration provided further reductions in total annual cost and energy by 63.0% and 73.0%, respectively, compared to the conventional RD configuration with excess LA reactant.

中文翻译：

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具有渗透蒸发混合配置的反应蒸馏以提高乙酰丙酸乙酯的生产

摘要 提出了一种基于反应蒸馏（RD）结合渗透蒸发膜系统的混合工艺设计，用于通过酯化生产乙酰丙酸乙酯（LAEE）。在建议的混合配置中，LAEE 是从 RD 塔的底部物流生产的，而来自塔顶的乙醇/水混合物则被送入另一个塔。附加塔顶部的共沸混合物在渗透蒸发单元中分离，富含乙醇的物流被循环到 RD 塔。还检查了具有过量乙醇反应物的 RD-only 配置，以研究过量乙醇反应物和共沸混合物分离的好处。具有渗透蒸发混合配置的拟议 RD 分别使年度总成本和能源减少了 61.0% 和 71.0%，与具有过量乙酰丙酸 (LA) 反应物的常规 RD 配置相比，与具有过量乙醇反应物的常规 RD 配置相比，分别为 6.0% 和 13.0%。结果证明了所提出的使用渗透蒸发的混合 RD 工艺在降低成本和提高 LAEE 生产能效方面的优势。结合影响膜通量的两个主要变量（操作温度和浓度梯度）讨论了不同的渗透蒸发布置（例如串联和并联布置）。串联排列更适合 LAEE 混合过程，因为在该过程中操作温度的影响占主导地位。还检查了 RD 渗透蒸发中的热强化，以探索进一步的能量降低。