Method for continuously extracting durene from coal-sourced aromatic hydrocarbon

Abstract

The invention provides a method for continuously extracting durene from coal-sourced aromatic hydrocarbon. The method comprises the steps: adding a coal-sourced aromatic hydrocarbon raw material intoa primary distillation tower, separating light components such as trimethylbenzene in the raw material from the top of the primary distillation tower by utilizing the negative pressure inside the primary distillation tower, and placing the light components into a light component storage tank by a heat radiator; making a residual tower bottom in the primary distillation tower enter a rectifying tower to obtain a durene-enriched solution with the mass percentage of 90%-95% at the top of the rectifying tower; and storing the durene-enriched solution into a middle durene storage tank, and then, delivering the durene-enriched solution into a multistage crystallizer for fractional crystallization to refine durene with the purity of 99% or above. By using the method, the purity of durene can be increased to 99% or above, a product is a white powdery / sheet-like crystal, and the conversion ratio of the product can be increased by 5%-10% during downstream pyromellitic dianhydride processing. Compared with a traditional freezing-centrifuging-squeezing process, the method is simple and safe in process operation and low in energy consumption and risk; and the method can be used for processing durene with different contents according to market demands, so that the market demands are met.

Description

technical field [0001] The invention belongs to the field of durene preparation, in particular to a method for continuously extracting durene from coal-based aromatics. Background technique [0002] Durene, also known as durene, chemical name: 1,2,4,5-tetramethylbenzene, molecular formula C 10 h 14 , is an important organic chemical raw material, mainly used in the production of pyromellitic dianhydride, pyromellitic dianhydride is an important raw material for the production of polyimide polymers, polyimide is a high temperature, low temperature It is a new type of synthetic material that is radiation-resistant, impact-resistant, and has excellent electrical and mechanical properties. It has important uses that cannot be replaced by other engineering plastics in the aerospace and electromechanical industries. With the continuous expansion of the polyimide market, the demand for durene as the main raw material for its synthesis is also increasing day by day. [0003] At p...

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Problems solved by technology

[0007] (1) The purity of the product is low, the content of impurities is high, and the color of the product is poor: the purity can only reach about 95% by using the cryogenic crystallization-centrifugation-pressing process, and the color of the produced durene is generally light yellow, which cannot be achieved pure white

[0008] (2) Low process safety and high risk: Since the mother liquor of durene contains some low-boiling aromatics, during the centrifugal separation process of the centrifuge, the separated small droplets are likely to generate static electricity due to friction, resulting in fire accidents

[0009] (3) During the downstream processing of pyromellitic dianhydride, the product has high impurity content and low conversion rate

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