Process method for extracting normal hexane and isohexane from crude hexane

Abstract

The invention discloses a process method for extracting normal hexane and isohexane from crude hexane. The process method comprises the following steps of: (1) mixing and heating raw material crude hexane and hydrogen gas and feeding into a hydrogenation reactor, and performing hydrodearomatization reaction under the action of a catalyst; (2) cooling a hydrogenation reaction product and then feeding in a low-pressure separation tank to perform gas-liquid separation, wherein gas phase is discharged from the top of the low-pressure separation tank, and oil phase at the bottom of the low-pressure separation tank is conveyed to a fractionation device to perform precise fractionation; (3) preheating the oil phase and feeding into a light component removal tower of the fractionation device to remove light components with fraction of less than 59 DEG C; (4) introducing remaining fractions of light component removal into an isohexane removal oil tower of the fractionation device to obtain high-purity isohexane; and (5) introducing the remaining fraction of isohexane removal into a normal hexane removal oil tower of the fractionation device to obtain the normal hexane. The process method has the advantages of simple and practical process, simple equipment, convenience in operation and stable and reliable product quality.

Description

technical field [0001] The invention belongs to the technical field of petrochemical separation methods, in particular to a process for extracting n-hexane and isohexane from crude hexane. Background technique [0002] n-Hexane is one of the most widely used hydrocarbon solvents in industry today. It is mainly used as a solvent for the polymerization of olefins such as propylene, as an extractant for edible vegetable oil, as a solvent for rubber and paint, and as a thinner for pigments. At present, industrial grade n-hexane products with a purity of 60%~80% (wt) are obtained mainly from the rectification and separation of platinum reforming raffinate. due to C 6 The boiling points of distillates are very similar (such as n-hexane at 69°C and methylcyclopentane at 71.8°C), so it is difficult to separate them by ordinary rectification. Precision rectification has high energy consumption, high production cost, and low yield, and it is difficult to obtain n-Hexane >99% (wt) ...

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Problems solved by technology

due to C 6 The boiling points of distillates are very similar (such as n-hexane at 69°C and methylcyclopentane at 71.8°C), so it is difficult to separate them by ordinary rectification. Precision rectification has high energy consumption, high production cost, and low yield, and it is difficult to obtain n-hexane >99% (wt) high-purity product; using special distillation method, the cost is high and the process is complicated, which also leads to the dependence of most of my country's high-purity n-hexane on imports

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