外部环流强化乙酸丁酯反应隔离壁蒸馏塔

Reactive dividing-wall distillation columns employing an external recycle to strengthen process of transesterification of butyl acetate with ethanol

针对具有较不利相对挥发度排序的四元可逆反应体系,使用常规反应蒸馏塔分离会使未反应的最重和次轻反应物堆集在塔底和反应段的顶部,降低反应的转化率。为解决这一问题,提出了2种不同的外部环流反应隔离壁蒸馏塔结构:中部环流反应隔离壁蒸馏塔和底部-中部环流双反应段隔离壁蒸馏塔。通过设置外部环流,将塔内未反应的反应物引回至反应段进行反应,同时环流实现的前提是在塔内设置隔离壁。以乙酸丁酯和乙醇的转酯反应的分离为例,对2种外部环流反应隔离壁蒸馏塔结构的有效性和可行性进行评估。研究结果表明:外部环流反应隔离壁蒸馏塔与传统反应蒸馏塔相比,稳态性能显著提高,具有更好的分离效果和经济性能。

When conventional reactive distillation columns( CRDC) were used for seperating the quaternary reacting mixtures with somewhat unfavorable relative volatilities ranking, the unconverted heaviest and light reactants tended to accumulate in the bottom and the top of the reactive section,respectively. And this led to the reduction of conversion of the reaction. To deal with this problem,two different reactive dividing wall distillation columns with an external recycle( RDWC-ER) were proposed: a reactive dividing-wall distillation column with an external recycle from the middle part of the column,and a reactive dividing-wall distillation column with two reactive sections and an external recycle from the bottom to a certain stage of the reactive section. The unconverted reactants were led back to the reactive section by the external recycle,which was achieved by setting vertical dividing wall within the column. The separation of the transesterification of butyl acetate with ethyl alcohol was chosen to evaluate the feasibility and effectiveness of the RDWC-ER. The results indicate that the RDWC-ER has better system performance,better separation effect and economic performance compared to CRDC.