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    丙酸正丙酯合成动力学及变压反应精馏节能工艺

    Kinetics and energy-saving pressure-swing reactive distillation process for synthesis of propyl propionate

    • 摘要: 针对丙酸与过量正丙醇酯化反应制备丙酸正丙酯过程中正丙醇/丙酸正丙酯二元体系存在夹点,分离能耗高等问题,提出热泵辅助的变压反应精馏集成工艺。以D005-IIS树脂为催化剂,测定该反应本征动力学实验数据,并回归动力学模型参数。对反应物系进行热力学分析,确定了反应精馏塔和分离精馏塔的操作压力,设计出变压反应精馏工艺,在此基础上进一步通过热泵和热集成强化变压反应精馏工艺,采用组合曲线比较三种工艺方案的节能效果,从能耗、年度总成本(TAC)和热力学效率等方面进行对比和分析。基于塔顶蒸汽再压缩的变压反应精馏热集成工艺相较于变压反应精馏工艺,回收余热1.7 MW,节能34.67%,TAC降低4.2%,热力学效率提升从7.84%至14.31%,表明热泵辅助变压反应精馏集成工艺具有显著的能源环境和经济效益。

       

      Abstract: A heat-pump-assisted pressure-swing reactive distillation integrated process was proposed to address the pinch point in the n-propanol/n-propyl propionate binary system and the high separation energy consumption during the preparation of n-propyl propionate via esterification of propionic acid with excess n-propanol. The intrinsic kinetic experimental data for the reaction were measured, and the kinetic model parameters were regressed using D005-IIS resin as the catalyst. The operating pressures of the reactive distillation column and the separation distillation column were determined by thermodynamic analysis of the reaction system, and a pressure-swing reactive distillation process was designed. On this basis, heat pump and heat integration were used to further intensify the pressure-swing reactive distillation process. The energy-saving performance of three process schemes was compared using composite curves, followed by analyses of energy consumption, total annual cost (TAC), and thermodynamic efficiency were carried out. Compared with the pressure-swing reactive distillation process, the overhead vapor recompression-based pressure-swing reactive distillation heat-integrated process recovered 1.7 MW of waste heat, decreased energy consumption by 34.67%, lowered TAC by 4.2%, and raised thermodynamic efficiency from 7.84% to 14.31%. These results indicate that there are substantial energy, environmental, and economic advantages to the heat-pump-assisted pressure-swing reactive distillation integrated process.

       

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