基于机械蒸汽再压缩和有机朗肯循环技术的双溶剂协同萃取精馏分离乙酸甲酯-甲醇-水节能工艺

Double solvent synergistic extractive distillation for methyl acetate-methanol-water based on MVR and ORC technology

针对双溶剂协同萃取精馏分离乙酸甲酯-甲醇-水三塔分离工艺特性及高能耗特点,把机械蒸汽再压缩(MVR)和有机朗肯循环(ORC)余热发电技术应用于该三塔的优化,提出了带中间再沸器的MVR热泵和ORC耦合MVR热泵两种节能精馏工艺。以年总费用(TAC)为精馏工艺评价指标,净输出功为ORC系统评价指标,采用Aspen Plus软件对提出的节能工艺进行模拟与优化。研究结果表明,就乙酸甲酯回收塔和甲醇回收塔而言,带中间再沸器的MVR热泵精馏工艺较常规双溶剂协同萃取精馏工艺能耗分别减少了57.38%和9.66%;TAC分别节省了31.34%和11.69%。而对于溶剂回收塔,带中间预分塔的ORC耦合MVR热泵精馏工艺较常规双溶剂协同萃取精馏工艺能耗减少了50.16%,TAC节省了36.13%。就整个萃取精馏系统而言,优化后的精馏工艺比原有双溶剂协同萃取精馏工艺能耗减少了45.48%,TAC节省了31.33%。

In the light of the high energy consumption characteristics of double solvent synergistic extractive distillation three tower process for methyl acetate-methanol-water,the mechanical vapor recompression(MVR)heat pump and organic Rankine cycle(ORC)waste power generation technologies were applied to optimization of the three towers,and the MVR heat pump distillation process with inter-mediate reboiler and MVR heat pump distillation process coupled with ORC were put forward.The results showed that in terms of methyl acetate recovery tower and methanol recovery tower,the MVR heat pump distillation process with inter-mediate reboiler can save energy by 57.38%and 9.66%,decrease TAC(total annual cost)by 31.34%and 11.69%compared with the conventional double solvent synergistic extractive distillation process.For solvent recovery tower,the MVR heat pump distillation process by pre column coupled with ORC can save energy by 50.16%and decrease TAC by 36.13%compared with the conventional double solvent synergistic extractive distillation process.In terms of the whole extractive distillation system,optimized distillation process can save energy by 45.48%and decrease TAC by 31.33%compared with the conventional double solvent synergistic extractive distillation process.