Normal hexane and benzene extractive distillation operating method

A technology of extractive distillation and extractive distillation column, which is applied in the field of n-hexane and benzene products, can solve the problems of unstable operation, low product purity, high energy consumption, etc., and achieve the effect of improving market competitiveness

Active Publication Date: 2013-08-14
TIANJIN UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The product obtained by the molecular sieve adsorption method has high purity, but the yield is not high; the yield of the azeotropic distillation method is high, but the product purity is not high; the product purity of the extractive distillation method is high, and it has a high yield
However, it is difficult to obtain high-purity n-hexane and benzene products in the existing extractive distillation. Liquid-liquid two-phase often occurs in the extractive distillation operation, and the operation is unstable; A large amount of high-quality steam is required for heating, and a large amount of cooling water is required for cooling the product, resulting in high energy consumption

Method used

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  • Normal hexane and benzene extractive distillation operating method
  • Normal hexane and benzene extractive distillation operating method

Examples

Experimental program
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Effect test

Embodiment 1

[0026] The mass composition of the mixture of n-hexane and benzene containing impurity components is as follows: n-hexane 38.6%, benzene 49.3%, methylcyclopentane 4.6%, cyclohexane 0.3%, n-heptane 1.4%, C7-C8 aromatics 3.5% %, unsaturated olefins 1.2%, other 1.1%.

[0027]C3-C8 mixed hydrocarbon raw materials such as raffinate, pyrolysis gasoline or straight-run gasoline from the aromatics extraction unit, after removing components with a boiling point lower than n-hexane, the feed rate is 2100kg / h, and the temperature is 70-73 °C, enter the middle part of the n-hexane extractive distillation column 101 of the n-hexane extractive distillation separation and purification system, and the compounded extractant N-methylpyrrolidone 11500kg / hr enters the n-hexane extractive distillation column 101 from above the feed plate. The operating pressure of the n-hexane extracting and rectifying tower 101 is 1.2 bara, the temperature at the bottom of the tower is 115-118°C, and the temperat...

Embodiment 2

[0033] Raw material composition is with embodiment 1.

[0034] The feed rate of raw materials is 2100kg / h, the temperature is 70-73°C, and it enters the middle part of the n-hexane extractive distillation column 101 of the n-hexane extractive distillation separation and purification system, and the compound extractant N-formylmorpholine is 9500kg / hr from The upper part of the feed plate enters the n-hexane extractive distillation column 101. The operating pressure of the n-hexane extracting and rectifying tower 101 is 1.0 bara, the temperature at the bottom of the tower is 123-125°C, and the temperature at the top of the tower is 73-75°C. The n-hexane obtained from the top of the n-hexane extraction rectification tower 101 has a purity of 99.5%wt, and the benzene content is less than 100ppm. The benzene-rich extractant solution obtained from the bottom of the rectification tower 101 is sent to the first extractant recovery tower 108 to recover the extractant.

[0035] The be...

Embodiment 3

[0040] Raw material composition is with embodiment 1.

[0041] The raw material feed rate is 2100kg / h, the temperature is 70-73°C, and enters the middle part of 101 of the n-hexane extraction, rectification, separation and purification system, and the compound extraction agent N-methylpyrrolidone 10500kg / hr enters the n-hexane from above the feed plate Extractive distillation column 101. The operating pressure of the n-hexane extracting and rectifying tower 101 is 1.1 bara, the temperature at the bottom of the tower is 119-121°C, and the temperature at the top of the tower is 70-72°C. The n-hexane obtained from the top of the n-hexane extraction rectification tower 101 has a purity of 99.5%wt, and the benzene content is less than 100ppm. The benzene-rich extractant solution obtained from the bottom of the rectification tower 101 is sent to the first extractant recovery tower 108 to recover the extractant.

[0042] The benzene-rich extractant solvent from the bottom of n-hexa...

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Abstract

The invention relates to a normal hexane and benzene extractive distillation operating method. The device comprises a normal hexane separation extraction and rectification and purification system and a benzene extractive distillation rectification and purification system. The compounded N-methylpyrrolidone solvent or N-formyl morpholine solvent serves as an extraction agent, so that the relative volatility of aromatic hydrocarbon and non-aromatic hydrocarbon is improved, and the relative volatility of methyl cyclopentane and normal hexane is improved; two extracting agent recovery towers are in negative pressure operation, and the tower kettle temperature is relatively low; liquid-liquid phase does not occur in the two extracting agent recovery towers in the operation process, and the operation is stable; the compounded N-methylpyrrolidone or N-formyl morpholine extracting is recovered and cooled and enters the extraction and rectification tower; and the benzene, toluene and non-aromatic mixtures are heated and enter the benzene extraction and rectification tower. The benzene content in the normal hexane product obtained by the operation method is lower than 100ppm, the purity of the normal hexane product is over 99.0 weight percent, and the purity of benzene product is over 99.9 weight percent.

Description

technical field [0001] The invention relates to an operation method for extraction and rectification of n-hexane and benzene, in particular to an operation method capable of obtaining high-purity n-hexane and benzene products. Background technique [0002] n-hexane (n-hexane, C 6 h 14 ) is a colorless transparent liquid, one of the widely used hydrocarbon solvents, and the most representative non-polar solvent. Industrial hexane solvent oil can be used in industries such as medicine, chemical industry, polymer materials, rubber industry and food, and the market demand for n-hexane products is very large. Benzene (Benzene, C 6 h 6 ) is an aromatic hydrocarbon with the simplest composition and structure. It is a colorless, sweet-smelling transparent liquid at room temperature and has a strong aromatic smell. Benzene is a basic petrochemical raw material. The output of benzene and the technical level of production are one of the signs of a country's petrochemical developme...

Claims

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Application Information

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IPC IPC(8): C07C9/15C07C15/04C07C7/08
Inventor 余英哲耿中峰马静李永辉欧阳胜利董秀芹张敏华
Owner TIANJIN UNIV
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