带有侧线采出回流的部分透热精馏的节能优化

Energy-saving optimization of partial diabatic distillation with side streams

以正丙醇-异丙醇体系为例,研究了带有侧线采出回流的部分透热精馏操作。在该操作中,精馏段侧线采出气相,经塔外冷凝后回流至塔内采出板上方;提馏段某塔板被同轴的夹套式中间再沸器环绕,侧线采出该板处的气相回流至塔内采出板上方。通过单因素分析和响应面法对精馏段和提馏段操作的相关工艺参数分别进行了模拟优化,并对相应操作的热力学性能和分离性能的变化进行了分析。最终优化结果表明:达到规定的分离效果,带有侧线采出回流的部分透热精馏相较于绝热精馏有效能损失降低了26.5%。带有侧线采出回流的部分透热精馏操作通过合理分配能量、降低对热剂和冷剂的品位要求和提高能量利用率,最终达到节能目的。

A partial diabatic distillation with side streams was studied by separating a binary mixture of n-propanol and isopropanol as an example. In the rectifying section, the vapor stream was withdrawn from the column and after condensation by the inter-condenser outside the column, it was then returned to the appropriate position above the output tray. In the stripping section, a jacketed inter-reboiler was set on the side of the section with the liquid inlet on the specific tray. The vapor stream in equilibrium was withdrawn from this tray and returned to its above appropriate position. The single-factor analysis and response surface method were used to simulate and optimize the relevant process parameters of the proposed operation in the rectifying section and the stripping section. The thermodynamic performance and separation performance of the scheme under the corresponding conditions were analyzed and showed that the exergy loss of the diabatic distillation with side streams was reduced by 26.5% as compared to that of adiabatic distillation when they had the same separation performance. The partial diabatic distillation with side streams achieves energy saving by rationally energy distribution, the energy quality reduction of heat and cold sources, and the improvement of energy-using efficiency.