Abstract:

To solve the problem of high energy consumption in the separation of dimethyl carbonate (DMC)/methanol (MeOH) azeotrope by traditional pressure swing distillation, an improved pressure swing distillation process assisted by heat pump was proposed, and the feasibility and economy of different heat pump schemes were explored. The research was carried out on the ASPEN PLUS simulation platform. The typical heat integrated pressure swing distillation process (H-PSD) was designed, and the energy bottleneck of the typical process and the direction of process improvement were analyzed based on column grand composite curves. Four types of heat pump assisted improved processes were proposed, and the design parameters of different schemes were obtained by simulation. The energy-saving effect and economy of different heat pump schemes were compared by using the methods of composite curve and economic analysis. The research showed that among four kinds of heat pump schemes, the vapour recompression heat pump with intermediate reboiler had the best economic performance. Compared with the typical heat integrated pressure swing distillation, the energy consumption, the total annual operating cost and the total annual cost of the system were reduced by 24.31%, 29.43% and 12.58%, respectively, which indicated the good energy-saving effect and economy performance of the heat pump assisted process.

Key words: binary mixture, dimethyl carbonate, distillation, simulation, heat pump

摘要：

针对传统变压精馏工艺分离碳酸二甲酯（DMC）/甲醇（MeOH）共沸物存在的高能耗问题，提出了基于热泵辅助的改进变压精馏工艺，并探索了不同热泵方案的可行性和经济性。该研究在ASPEN PLUS模拟平台上进行。首先，设计出传统的热集成变压精馏工艺（H-PSD），并通过塔总组合曲线分析了传统工艺用能瓶颈和工艺改进方向；然后，提出了4种不同型式的热泵辅助的改进工艺，并通过模拟技术取得不同方案的设计参数；最后，采用组合曲线和经济性分析相结合的方法，比较了不同热泵方案的节能效果和经济性。研究表明，各种热泵方案中，基于中间再沸器的蒸汽再压缩式热泵的节能效果及经济性最好。与传统热集成变压精馏比较，过程能耗降低了24.31%，年均操作费用降低了29.43%，年度总成本可降低12.58%，体现了热泵辅助工艺的良好节能效果和经济性。

关键词: 二元混合物, 碳酸二甲酯, 蒸馏, 模拟, 热泵