Method for one-section abstraction distillation separation cracking carbon 5-cut fraction

Abstract

The invention relates to a section of extracting, rectifying, separating and cracking 5 carbon stream which belongs to the technical field of separating 5 carbon stream, and provides a method of a section extracting, rectifying, separating and cracking 5 carbon stream in order to solve the problems of a second extraction unit in the existing carbonium 5 separation process, such as high energy consumption, complex operation, harsh operation demand and big extraction solvent loss, etc.; the method adopts distillation method to remove isoprene and uses an azeotropy distillation method to remove alkyne; a polymerization grade isoprene product is obtained with no need of two times extraction and the second extraction unit and a solvent refining tower are omitted. The method of a section extracting, rectifying, separating and cracking 5 carbon stream is simple in operation, easy in operation and low in production cost; the energy consumption of the polymerization grade isoprene product unit of the invention is about 20 percent of the existing second extraction unit in the same treating load of the raw material; m-pentadiene is produced from a pre-deheavy tower kettle and does not enter an extraction and distillation unit; the throughput of the extraction and distillation tower, an absorption tower and a de-heavy tower is reduced by 50 percent with the energy consumption being reduced by 50 percent correspondingly, and construction cost and production cost are reduced largely. .

Description

technical field [0001] The present invention relates to a method for separating C5 fractions, more specifically, the present invention relates to a method for separating and cracking C5 fractions to prepare polymer grade isoprene products. Background technique [0002] In the process of producing ethylene from petroleum cracking, a considerable amount of C5 fraction is by-produced, and the C5 fraction is rich in diolefins such as isoprene, cyclopentadiene and piperylene. These diolefins are chemically active and are important chemical raw materials. Due to the difference in cracking raw materials, cracking depth and separation degree of petroleum hydrocarbons, the content of diolefins in cracked C5 fractions is different, and the total content is between 40% and 60%. Therefore, the separation and utilization of C5 fractions has far-reaching significance for improving the economic benefits of ethylene plants and comprehensively utilizing petroleum resources. [0003] The cr...

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Problems solved by technology

[0005] Aiming at the problems of high energy consumption, difficult operation, easy blockage, large solvent loss and unsafety in the existing second extraction unit, the present invention proposes a method for one-stage extraction and rectification to separate and crack C5 fractions. The method utilizes rectification The method removes cyclopentadiene and uses azeotropic distillation to remove alkynes, and the product of polymer grade isoprene can be obtained without a second extraction unit

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