基于MVR热泵精馏的混合醇热集成分离工艺

机械蒸汽再压缩(MVR)热泵技术是把低品位的蒸汽通过压缩转变为高品位的蒸汽,循环用于热源的供热以减少能耗。而热集成技术则是合理的匹配冷热物流的换热,以提高物流的有效能利用率。鉴于精馏过程的高能耗和低热力学效率,本文以四元混合醇的分离为研究对象,把基于MVR热泵技术的热集成精馏工艺应用于该体系的分离,提出并研究了该体系带热集成与不带热集成各种MVR精馏工艺;以能耗和年总费用(TAC)为评价指标,采用Aspen Plus 软件对各分离工艺进行模拟与优化,确定各分离工艺的操作参数与设备参数。研究结果表明,与常规顺序分离工艺相比,MVR精馏工艺节约能耗50%以上,节约年总费用约61%。带热集成MVR精馏工艺与不带热集成MVR精馏工艺相比,在能耗和年总费用方面,优势相当,但前者热力学效率提高了约9.5%。

Heat integrated separation technology for separating mixed alcohol based on the MVR heat-pump distillation

The low grade steam is transformed into a high grade steam through the compression by mechanical vapor recompression(MVR) heat pump technology, and the high grade steam is cyclic utilized for heat source to reduce energy consumption. The heat integration technology is reasonable to match the heat exchange of cold and hot logistics to improve the effective energy utilization of logistics. In view of the high energy consumption and low mechanical efficiency of the distillation process, heat integrated separation technology based on the MVR heat-pump distillation was applied to separate the four mixed alcohol system in this research, and the MVR heat-pump distillation process with and without heat integration were proposed. Based on the minimum total annual cost(TAC) and energy consumption, simulations for the each kind of distillation process were performed by Aspen Plus software, and the optimal operating parameters and plant parameters were determined. The simulation results showed that the MVR heat-pump distillation can save energy by 50% and total annual cost by 61% respectively compared with the conventional order separation process. Both of the MVR heat-pump distillation with and without heat integration have the same excellent performance in energy saving and annual total cost saving, but the former can improve the thermodynamic efficiency by 9.5%.