Overcome the equilibrium limitation in para-Xylene production by using reactive distillation method

Abstract

To overcome the equilibrium limitation of liquid phase-Xylene isomerization in maximum para-Xylene (PX) yield at 24% molar is a significant objective in either academics or industrial application, regarding the importance of PX in various polyester productions. In this study, integration of reaction and extractive distillation into a reactive distillation column (RDC) is proposed as a solution for the enhancement of PX yield. The desired product is simultaneously generated and purified in the only equipment so the conversion could be forward shifted to overcome equilibrium limitation in Xylene isomerization. Obstacles relating to the close boiling points of xylenes are alleviated by an inert solvent introduced into the system to facilitate the separation of xylene isomers. The flowsheet which is configured by a reactive distillation column and a recovery column manifests advantages of the method for para-Xylene production. The highest PX yield can be obtained up to 37% molar, while other cases result in the yield of p-Xylene higher than 25% molar. The effect of design parameters, including the number of stages in reactive-, rectifying- and stripping sections on process performance, is carefully examined to study the behavior of the RDC and system.