基于蒸汽再压缩的多储罐间歇精馏全回流操作

Vapor Recompression Scheme for Multivessel Batch Distillation with Constant Total Reflux Operation

多储罐间歇精馏全回流操作(MVBD)是一种高效省时的新型间歇精馏操作方式。为了进一步提高其热力学效率,提出将蒸汽再压缩技术应用于MVBD,构成基于蒸汽再压缩的多储罐间歇精馏全回流操作(VRMVBD)。该操作利用压缩机将塔顶蒸汽压缩到较高的压力,使其在塔釜再沸器处冷凝,释放出的潜热供给塔釜料液再沸,从而减少塔釜再沸器对外部热源的需求量。根据压缩机的运转方式,VRMVBD可分为定速VRMVBD和变速VRMVBD。通过模拟分离乙醇-正丙醇的实例表明,VRMVBD能降低操作能耗并提高经济效益,而且变速VRMVBD比定速VRMVBD更具优势。相比MVBD,变速VRMVBD能降低77.62%的操作能耗以及38.71%的年度总费用。

Multivessel batch distillation with constant total reflux operation（MVBD） is efficient and time-saving for separation of a binary mixture. Aiming to further improve its thermodynamic efficiency, the vapor recompression approach was introduced in MVBD, which was referred to as VRMVBD. The overhead vapor was compressed up to the necessary pressure for its condensation in the reboiler. The latent heat of compressed overhead vapor was utilized for vaporizing the reboiler liquid. This process indicates a decrease of energy requirements from external source. VRMVBD is accompanied with a compressor that runs at a fixed as well as variable speed. The features of VRMVBD were illustrated by separating a binary mixture of ethanol and n-propanol. In conclusion, VRMVBD appears overwhelmingly superior to MVBD in terms of thermal efficiency and economic performance. Moreover, the variable speed VRMVBD shows a better performance than that of the fixed speed VRMVBD. Compared with MVBD, the variable speed VRMVBD scheme secures a 77.62% and 38.71% reduction in energy consumption and total annual cost, respectively.