Method for separating cracked carbon 5 using azeotropic super fractionation and extractive distillation coupling

Abstract

This invention has disclosed a method of separating carbon5 by azeotropic rectification and extractive distillation. Its characteristic is it adopts azeotropic rectification to take off light-unit and heavy-unit gained isoprene- n-pentane azeotrope accord with polymerisation grade, then with extractive distillation make isoprene separated from n-pentane to get t polymerisation grade isoprene. Because targets that this invention extracts the distillation and deals with are only mixture of isoprene and n-pentane, but not make up carbon five hydrocarbon, thus greatly alleviated the questions of using solvents, such as solvent toxicity, retrieving , resolving , environmental protection, etc. When producing pure isoprene and n-pentane, this invention also could get 1,3-piperlene of high concentration.

Description

Technical field:

[0001] The invention relates to a separation method of mixed carbon five hydrocarbons, in particular to a method for separating diolefins and n-pentane from ethylene cracking by-product carbon five by combining azeotropic super-rectification and extractive distillation. Background technique:

[0002] Both refineries and cracking plants by-produce a large amount of carbon five hydrocarbons, most of which are not well utilized. Taking an ethylene plant with an annual output of 300,000 tons as an example, the by-products are about 40,000-50,000 tons of carbon pentahydrocarbons, including 7,000-10,000 tons of isoprene, and 6,000 to 7,000 tons of cyclopentadiene and piperylene. These diene components are important raw materials for synthetic rubber, resins, coatings, spices, medicines, pesticides and other chemical products. If they can be separated and utilized, better economic benefits will be received.

[0003] The composition of carbon pentahydrocarbons is c...

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