芳烃联合装置模拟与优化(Ⅱ)——芳烃抽提单元的全流程模拟与优化

Simulation and Optimization for Aromatics Complex Plants(Ⅱ)——Whole-process Simulation and Optimizatin for Aromatic Extraction Unit

利用Aspen Plus流程模拟软件,建立芳烃抽提过程全流程模拟模型,抽提塔和非芳烃水洗塔采用Extract模型,提馏塔、回收塔、水分馏塔、溶剂再生塔采用RadFract模型,两相分离器采用Decanter模型,热力学采用NRTL或UNIQUAC方程,由于软件里溶剂环丁砜与烃类的二元交互作用参数缺失严重,采用试验和文献数据进行回归。通过模型,对芳烃抽提过程的关键参数,如溶剂比、返洗比、水洗比、溶剂温度、溶剂浓度、塔顶回流和塔底热负荷、塔压等进行综合分析,在权衡芳烃回收率和芳烃纯度、溶剂溶解度和选择性基础上,选择最优的操作参数,为芳烃抽提单元操作优化提供技术支撑。中国石化(SINOPEC)共有24套芳烃抽提/苯抽提装置(包括合资企业),对其中的13套芳烃抽提/苯抽提装置实施了流程模拟优化方案,合计实现装置挖潜增效2900万元/a。

With the use of the Aspen Plus process simulation software ,researchers established whole-process simulation models for the aromatic extraction process.The Extract model was used for the extractor and the non-aromatics water scrubber,the RadFract model was used for the stripping tower,the recovery tower,the water fractionating column and the solvent regenerating colum,the Decanter model was used for the two- phase separator,and the NRTL or UNIQUAC equation was used for thermodynamics.As many parameters on the binary interaction between solvent sulfolane and hydrocarbons were missing in the software,experimental and literature data was used for regression.With the help of these models,these researchers analyzed the key parameters involved in the aromatic extraction process,such as solvent ratio,backwashing ratio,water scrubbing ratio,solvent temperature,solvent concentration,top reflux and bottom heat load,and column pressure.While considering the recovery of arches,the purity of arenes,the solubility of solvent and selectivity,they selected the optimum operational parameters and provided technical support for an optimized operation of the aromatic extraction unit.Sinopec has a total of 24 aromatic extraction/benzene extracting units （including joint-venture faeilities）,13 of which have been optimized using process simulation software.The optimization has brought Sinopee an additional 29 million yuan in revenue annually.