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, the xylene fractionation unit comprises a xylene tower and a heavy aromatics tower, the adsorption separation unit comprises an adsorption separation tower, and a p-xylene material flow and a poor p-xylene material flow are separated out; the isomerization reaction unit comprises an isomerization reactor and a heptane removal tower connected with the isomerization reactor; the disproportionation and transalkylation unit comprises a disproportionation and transalkylation reactor, a carclazyte tower and a disproportionation and transalkylation reaction product separation tower which are connected in sequence, and the alkylation unit comprises a benzene tower, a toluene tower and an alkylation reactor. According to the invention, the conversion rate of toluene is improved, the product benzene is fully utilized to be converted into p-xylene, and 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 value-added product p-xylene is improved, and the economic benefit and the social benefit are improved.

Description

technical field [0001] The present invention relates to the production technology of p-xylene, in particular to C 8 + The invention discloses a process system and a process method for producing p-xylene with mixed aromatics as raw material. 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 four isomers of ortho-xylene, para-xylene, meta-xylene and ethy...

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

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