Production device and production process of p-xylene

Abstract

The invention discloses a production device and a production process of p-xylene. The production 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 tower, a raffinate tower, a finished product tower, a finished product tower reboiler I and a finished product tower reboiler II, and the isomerization reaction unit comprises an isomerization reaction rectifying tower, a white clay tower, an isomerization reaction heating furnace, a heatexchanger II, a heat exchanger III, a heat exchanger V and a compressor. The invention also provides a production process of p-xylene. According to the invention, the equipment investment is reduced,the operation load of the xylene tower is reduced, the fuel gas consumption of the xylene reboiler is saved, the isomerization reaction and the product separation are carried out at the same time soas to achieve the coupling utilization of energy, the heat exchange network is optimized, the fuel gas consumption of the isomerization reaction heating furnace is reduced, 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 production device and process of 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...

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Problems solved by technology

In this process, the heat of the reboiler of the finished product tower is provided by the desorbent and the bottom liquid of the xylene tower, which consumes a lot of energy, and the isomerized product is removed by the deheptanizer. 7 Most of the light hydrocarbons are recycled back to the xylene tower, increasing the operating load of the xylene tower and increasing the fuel consumption of the xylene reboiler

In addition, all isomerized products must be cooled. After the hydrogen gas that has not participated in the reaction is separated, the cooling load is relatively large; the material after the hydrogen gas is separated needs to be reheated, and it enters the deheptanizer for further separation. The material is cooled first and then heated. problem, resulting in a waste of energy

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