分壁塔替代两塔分离芳烃流程改造的研究

ON-SITE REVAMPING OF TWO-COLUMN AROMATIC SEPARATION PROCESS USING DIVIDED-WALL COLUMN

分壁精馏塔以其特有的结构和分离方法,在能耗和投资上较常规多塔串联分离多组分混合物有明显优势。本研究以芳烃抽提装置中精馏单元分离苯、甲苯、二甲苯的常规两塔分离序列为研究对象,提出和对比了3种分壁精馏塔的就地改造方案。建立了常规两塔分离及3种改造方案的稳态严格精馏模型,分析和对比了3种改造方案的节能效果。结果表明,3种分壁精馏塔的改造方案的节能效果分别为11.5%,32.4%,34.0%,其中将原两塔流程中苯塔改为分壁精馏塔的精馏段、甲苯塔改为预分馏段和提馏段的方案更易在工程与实施。

The structure and separation mechanism of a divided-wall column(DWC)are different from a conventional distillation column.The DWC could save considerable energy consumption and capital cost for separating ternary mixtures compared with the conventional column.This work studied three alternative methods for on-site revamping of conventional two column BTX separation process using DWC.The simulation models of steady-state rigorous distillation for the conventional two column separation process and the 3 revamping schemes were established and compared the energy saving effect.Result showed that the three DWC revamping schemes have obvious advantages in energy saving over the conventional 2-column sequence,the energy savings of 3 schemes are 11.5%,32.4%and 34.0%,respectively.The scheme where the benzene column in the 2-column sequence is used as a rectifying section of the DWC and the toluene column is revamped into prefractionation section and stripping section of the DWC is of the best and easy to be implemented.