Device and process for producing p-xylene

Abstract

The invention discloses a device and a process for producing p-xylene. The device comprises a xylene fractionation unit, an adsorption separation unit and an isomerization reaction unit, wherein the adsorption separation unit comprises an adsorption separation tower, an extraction liquid fractionating tower, a raffinate tower and a heat exchanger II, and the isomerization reaction unit comprises an isomerization reactor, an isomerization product fractionating tower, a white clay tower, a gas-liquid separation tank, an isomerization reaction heating furnace, a heat exchanger III, a heat exchanger IV, a heat exchanger V, a heat exchanger VI, a compressor and an air cooler. The invention also provides a process for producing p-xylene. According to the invention, the equipment investment and the occupied area are reduced, the operation load of the xylene tower is reduced, the fuel gas consumption of the xylene reboiler and the isomerization reaction heating furnace is saved, the heat exchange network is optimized, the energy consumption is greatly reduced, and the economic benefit and the social benefit are improved.

Description

technical field [0001] The invention relates to a device and process for producing p-xylene. Background technique [0002] P-xylene is one of the important basic organic raw materials in the petrochemical industry. It is mainly used to produce terephthalic acid (PTA) and dimethyl terephthalate (DMT). It is widely used in chemical fibers, synthetic resins, pesticides, and medicines. , plastics and other production areas. In 2017, the apparent consumption of p-xylene in my country will reach 2400×10 4 t, the production capacity of p-xylene unit reaches 816×10 4 t, accounting for about 20% of global production capacity, my country is already the world's largest producer of p-xylene. [0003] C 8 Aromatics include o-xylene, p-xylene, m-xylene and ethylbenzene four isomers, among which p-xylene has the largest market, so the industry usually prefers to increase the specific C 8 The production of para-xylene from aromatics feedstock sources even maximizes it. Due to their si...

AI Technical Summary

Problems solved by technology

In this process, the rectification of the extracted liquid is a double-tower process of the extracted liquid tower and the finished product tower, which consumes a lot of energy, and after the isomerization product is removed by the deheptanizer to remove light hydrocarbons below C7, Most of it is recycled back to the xylene tower, increasing the operating load of the xylene tower and increasing the fuel consumption of the xylene reboiler

At the same time, the isomerization product is completely cooled after exchanging heat with the feed, and reheated after the hydrogen is separated, so there is an unreasonable phenomenon of energy utilization.

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