Method for refining beta-methylnaphthalene by melting crystallization

A technology of melt crystallization and methylnaphthalene, which can be used in crystallization purification/separation, organic chemistry, etc., can solve the problems of long process, complicated equipment and operation, and achieve the advantages of low operating cost, simple equipment and process, and improved operating conditions for workers. Effect

Active Publication Date: 2008-05-14
天津天达联合工程技术有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Although the method has less pollution, the process is longer and the equipment and operation are complicated

Method used

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  • Method for refining beta-methylnaphthalene by melting crystallization

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] The high-purity 98.1% β-methylnaphthalene was subjected to film-hanging operation at 0°C for 2 minutes, then the temperature of the crystallizer was raised to 15°C, and 75.0% of the β-methylnaphthalene raw material was heated to 25°C and then put into the crystallizer In the process, after allowing the crystal layer to grow for 1.5 hours, cool down at 2°C / h to crystallize and grow the crystal layer for another 3.5 hours. The thickness of the crystal layer is about 20 mm. The end temperature was 30°C, and the crystal was heated to 40°C to melt, and the purity by gas chromatography analysis was 98.06%. The melting amount of β-methylnaphthalene in the sweating operation is 40% by weight, and the sweating mother liquor is cyclically crystallized. The total crystallization yield was 64.6%.

Embodiment 2

[0027] The high-purity 97.1% β-methylnaphthalene was subjected to film-hanging operation at 5°C for 1 min, then the temperature of the crystallizer was raised to 20°C, and 85.6% of the β-methylnaphthalene raw material was heated to 34°C and then put into the crystallizer In the process, let the crystal layer grow for 2.5 hours, then cool down at 3°C / h to grow the crystal layer for another 5 hours, the thickness of the crystal layer is about 28mm, discharge the crystallization residual liquid and perform sweating operation, the heating rate is 2°C / h, sweating The end temperature was 31°C, and the crystal was heated to 41°C to melt, and the purity by gas chromatography analysis was 98.47%. The melting amount of β-methylnaphthalene in the sweating operation is 31.3% by weight, and the sweating mother liquor is cyclically crystallized. The total crystallization yield was 72.3%.

Embodiment 3

[0029] The high-purity 98.5% β-methylnaphthalene was subjected to film-hanging operation at 10°C for 1.5 minutes, then the temperature of the crystallizer was raised to 25°C, and the raw material of 90.1% β-methylnaphthalene was heated to 40°C and put into crystallization In the device, let the crystal layer grow for 2.0 hours, then cool down at 4°C / h to crystallize and grow the crystal layer for another 5 hours, the thickness of the crystal layer is about 31mm, discharge the crystallization residual liquid and perform sweating operation, the heating rate is 5°C / h, The end temperature of sweating is 28°C, and the crystal is heated to 43°C to melt, and the purity by gas chromatography analysis is 98.66%. The melting amount of β-methylnaphthalene in the sweating operation is 24.9% by weight, and the sweating mother liquor is cyclically crystallized. The total crystallization yield was 83.4%.

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Abstract

The invention relates to a method of refining Beta-methylnaphthalene by fusing crystallization, comprising the following procedures: firstly, the temperature of the crystallizer condensate is reduced to 0 to 10 DEG C, and the fusing Beta-methylnaphthalene with high purity is led into the crystallizer for about 1 to 2 minutes, then the Beta-methylnaphthalene is let out; the temperature of the crystallizer is increased to 15 to 25 DEG C, and the feed liquid at 25 to 40 DEG C is transferred into the crystallizer and the crystal layer is let to grow for 0.5 to 2.5 hours, and then the crystal layer is made to regenerate for 1.5 to 6 hours with the cooling speed of 2 to 4 DEG C per hour; the crystallizer is kept for 15 to 25 minutes with the temperature and then is warmed up with the heating rate of 2 to 5 DEG C per hour to fuse the crystal layer. When the crystallizer is warmed up to above 40 DEG C, the whole crystal layer is melted and then the Beta-methylnaphthalene with high purity can be collected. The invention has the advantages of simple technology and equipment, low operational cost, no pollution, high purity and high yield of the obtained Beta-methylnaphthalene, completely closed device, and greatly improved operation conditions of the workers.

Description

technical field [0001] The invention relates to the technical field of deep processing and purification of tar, in particular to a method for refining β-methylnaphthalene by melting crystallization. Background technique [0002] The production of methylnaphthalene is divided into the production of coal tar methylnaphthalene and the production of tar methylnaphthalene, a by-product of petroleum cracking. Coal tar methylnaphthalene has a long history of development and accounts for a large proportion of the market share of methylnaphthalene. [0003] The contents of α-methylnaphthalene and β-methylnaphthalene in coal tar account for about 1.0% and 1.5% respectively. Mixed methylnaphthalene and its isomers have a wide range of uses. β-methylnaphthalene is more versatile than α-methylnaphthalene. Because the tar processing technology of each coking plant is different, the sources of methylnaphthalene are also different. Generally speaking, the raw m...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C15/24C07C7/14
Inventor 卫宏远
Owner 天津天达联合工程技术有限公司
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