Process system and process method for increasing yield of p-xylene

Abstract

The process system comprises a xylene fractionation unit, an adsorption separation unit, an isomerization reaction unit, a disproportionation and transalkylation unit and an alkylation unit, according to the process system and the process method disclosed by the invention, the conversion rate of toluene is improved, the conversion of the product benzene to p-xylene is fully utilized, and meanwhile, the aim of separating reactants and reaction products in one tower is fulfilled by adopting a divided wall tower technology, so that the energy consumption of the device is reduced, the yield of the high-added-value product p-xylene is improved, and the economic benefit and the social benefit are improved.

Description

technical field [0001] The invention relates to a method for producing p-xylene, in particular to a process system and a process method for producing p-xylene. Background technique [0002] Paraxylene is one of the important basic organic raw materials in the petrochemical industry. It is mainly used to prepare terephthalic acid (PTA) and dimethyl terephthalate (DMT). It is widely used in chemical fibers, synthetic resins, pesticides, pharmaceuticals , plastics and other production fields. According to statistics, in 2019, my country's PX production capacity increased significantly by 11.9 million tons, and the total production capacity reached 25.03 million tons, with a production capacity growth rate of 70.4%, which is the highest growth rate of PX production capacity in recent years. [0003] C 8 Aromatic hydrocarbons include ortho-xylene, para-xylene, meta-xylene and four isomers of ethylbenzene, of which para-xylene has the largest market, so the industry usually hope...

AI Technical Summary

Problems solved by technology

[0005] In this process, toluene and C 9 The p-xylene selectivity of the disproportionation and transalkylation of aromatics is less than 30%, which leads to a large circulation volume of the disproportionation and transalkylation unit, and increases the energy consumption of the device; at the same time, the product benzene is not fully utilized as a product out of the device. Thereby further reducing the total yield of p-xylene