Method for continuously extracting durene from MTG heavy petrol

Abstract

The invention discloses a method for continuously extracting durene from MTG heavy petrol. In the method, light components such as trimethylbenzene are removed from the MTG heavy petrol by a light component removing tower, a gas phase obtained at the top of the tower is cooled and then serves as a gasoline blending component, a product obtained at the bottom of the tower enters a heavy component removing tower to remove heavy components such as pentamethylbenzen. A durene enriched solution at the top of the heavy component removing tower enters a continuous multistage countercurrent fractional crystallization tower for separation and purification, after the separation and purification, a durene product with the purity more than 99% is obtained at the bottom of the crystallization tower, and a residual solution is recycled from the top of the crystallization tower. By adopting the process method in the invention, continuous charging can be realized, high purity durene can be continuously obtained and the residual solution can be continuously recycled; the method is simple in operation and low in energy consumption and can realize industrial production.

Description

technical field [0001] The invention relates to a process for purifying durene, in particular to a process for continuously purifying durene from MTG heavy gasoline. Background of the invention [0002] Durene is an important fine chemical raw material, mainly used in medicine, powder coating matting agent, dye, pesticide, surfactant and so on. The main use of durene is to produce pyromellitic dianhydride, and then to produce polyimide. In recent years, the market demand for polyimide has been increasing, and the demand for durene is also increasing day by day. [0003] Methanol is the cornerstone of petrochemical industry. Through certain reactions, various petrochemical products can be produced. Among them, methanol-to-gasoline (MTG) technology has attracted more and more attention. Gasoline produced by methanol conversion can be used directly after simple processing, and can also be used as a high-quality gasoline component for high-clean gasoline blending. However, t...

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Problems solved by technology

[0004] At present, the purification technology of durene mainly includes methods such as freeze crystallization or rectification-freeze crystallization, solvent crystallization, etc. The following problems exist in the process of purifying durene by these traditional methods: (1) The refrigerant temperature requirement for producing durene is relatively high Low, high energy consumption; (2) low product purity; (3) crystallization follow-up treatment is relatively complicated

Patent 103524288A discloses a method for purifying durene. The method stipulates that the concentration of durene raw material is 50-70%. After the raw material is crystallized at -15-20°C in a freezing crystallization tank, it needs to go through a centrifuge to realize solid product and crystallization mother liquor. Since the centrifuged solid product contains a certain amount of crystallization mother liquor, it needs to be further separated after being filtered by a filter press. The purity of the purified durene is only 70-80%. The crystallization and subsequent treatment process is complicated, and the product low purity

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