考虑内部热集成的乙二醇反应精馏系统设计与优化

Design and optimization of an internally heat integrated reactive distillation column for ethylene glycol production

针对环氧乙烷水合制乙二醇反应精馏过程反应热的利用和系统能量更大集成问题,提出一种将反应段和提馏段分割、从反应段移出热量供提馏段加热的内部热集成反应精馏塔(R-HIDiC)的设计。利用Aspen Plus模拟软件,分析了内部热集成的可能性,优化了内部热交换量及其分布,给出了一种不需要再沸器的能量最大集成方案。研究表明,与传统的反应精馏塔相比,通过对内部热集成进行优化,乙二醇反应精馏塔可取消再沸器,系统需要的能量只由环氧乙烷水合反应热和外部压缩机提供,其操作费用将降低约47.2%,总费用将降低约39.1%,体现了其技术和经济优越性。

The problem to seek further heat integration for the hydration of ethylene oxide by reactive distillation （RD） to produce ethylene glycol, which involves reactions with highly thermal effect, was investigated. An innovative process, internally heat-integrated RD column （R-HIDiC）, was proposed to maximize energy efficiency of the system, in which the reactive section and stripping section was partitioned into two parts with different operating pressures so that the internal heat transfer between reactive section and stripping section was allowed. Steady-state simulations based on Aspen Plus software were performed to investigate the feasibility of internal heat integration, and an energy integration design without the need of reboiler was provided by optimizing the heat distribution in R-HIDiC. The results obtained demonstrated that, comparing with the conventional design, the proposed R-HIDiC design did not need a reboiler, thus, the total energy input can be supplied by the heat of reaction of the hydration of ethylene oxide and the electricity power of compressor, which leads to a reduction of the operating and total cost by 47.2% and 39.1%, respectively.