Method for separating arene by extraction and rectification

Abstract

The arene extracting, rectifying and separating process includes pre-distilling arene containing mixture to prepare C6-C7 fraction and C8 fraction; introduing the C6-C7 fraction to middle part of extracting and rectifying tower to contact with selective solvent introduced from upper part for extraction and rectification; introducing the tower bottom effluent to recovering tower for separating arene from the solvent; separating the top effluent from the extracting and rectifying tower to obtain non-arene exhaust system and injecting water into poor solvent; condensating the top effluent from recovering tower to separate arene system while introducing water to recovering tower for re-use; and returning the bottom obtained poor solvent from the recovering tower to extracting and rectifying tower for reuse. The said process is suitable for recovering high purity benzene and toluene from hydrocarbon mixture with high arene content and has simple operation and low power consumption.

Description

technical field [0001] The invention relates to a method for extracting and rectifying the separation of aromatics, specifically, a method for mixing water into a solvent to improve solvent selectivity, thereby improving the separation efficiency of aromatics. Background technique [0002] There are two main methods for separating aromatics, namely benzene (B), toluene (T) and xylene (X) from reformed oil or pyrolysis hydrogenated gasoline. One is the liquid-liquid extraction method, which is essentially a combined process of liquid-liquid extraction and extractive distillation. The other type is extractive distillation. Compared with the liquid-liquid extraction method, the extractive distillation method has the advantages of simple process and operation, low equipment investment, and low energy consumption, and is especially suitable for recovering aromatics from hydrocarbon mixtures with high aromatic content. Since xylene is mainly used as a raw material for the produc...

AI Technical Summary

Problems solved by technology

The problem with these processes is that it is difficult to obtain high-purity aromatics, especially high-purity benzene and toluene products

Another treatment method is to set up a water stripper to strip the non-aromatics in the water, and then recycle the purified water to the recovery tower. Although this avoids the pollution of a small amount of non-aromatics to aromatics, it needs to increase the water stripper and other facilities, increasing investment and energy consumption

Images