Batch extraction-rectification-separation method of dichloromethane-methanol azeotropic mixture

A technology of azeotrope and dichloromethane is applied in the field of batch extraction, rectification and separation, which can solve the problems of polluting the environment, difficult to separate, and no data yet, and achieves the effects of flexible operation and low investment in equipment costs.

Inactive Publication Date: 2013-09-18
UNIV OF JINAN
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The dichloromethane-methanol mixture produced in the production process is difficult to separate because dichloromethane and methanol form an azeotrope (the mass fraction of methanol is 7.3%). If it is not recovered, it will not only pollute the environment, but also increase production costs. Therefore, it is of great significance to develop a separation method for dichloromethane-methanol azeotrope
There are many articles and patents on extractive distillation, but there is no publicly published information on extractive distillation and separation of dichloromethane-methanol azeotropic system

Method used

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  • Batch extraction-rectification-separation method of dichloromethane-methanol azeotropic mixture

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0009] Example 1 A batch extraction and rectification device is used, and 500 L of dichloromethane-methanol azeotrope (wherein 7% of methanol and 93% of dichloromethane are both in mass percent) is put into the heating tank, and the extraction agent selected for the test is propanol , turn on the heat source of the heating kettle and the cold source of the condenser, after a period of reflux at the top of the extraction and rectification column, the temperature at the top of the column is stable, and the extraction agent is added. h, total reflux operation, when the temperature at the top of the extractive distillation column is 39.4-40.5°C, the dichloromethane content in the distillate is ≥99%, and the reflux ratio is 3:1, and the output speed is 200 L / h . When the temperature at the top of the extractive distillation tower is 40.5-64°C, take out the dichloromethane-methanol transition section, and stop adding the extractant, the reflux ratio is 9:1, when the temperature at t...

Embodiment 2

[0010] Example 2 A batch extraction and rectification device is used, and 500 L of dichloromethane-methanol azeotrope (wherein 7.2% of methanol and 92.8% of dichloromethane are both in mass percent) is put into the heating tank, and the extraction agent selected for the test is ethylene dichloride Alcohol, turn on the heat source of the heating kettle and the cold source of the condenser. After the top of the extraction and rectification tower is refluxed for a period of time, the temperature of the top of the tower is stable, and the extraction agent is added. The feeding position of the extraction agent is near the top of the tower. / h, total reflux operation, when the temperature at the top of the extractive distillation column is 39.4-40.5°C, the dichloromethane content in the distillate is ≥99% and starts to discharge, the reflux ratio is 2:1, and the discharge speed is 300 L / h h. When the temperature at the top of the extractive distillation tower is 40.5-64°C, the dichl...

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Abstract

The invention discloses a batch extraction-rectification-separation method of a dichloromethane-methanol azeotropic mixture, and belongs to the separation technology of the rectification-separation method of dichloromethane-methanol azeotropic mixture. The method comprises the following steps of: by taking propanol, isopropanol, 1,3-propanediol, glycol, tertiary butanol, N,N-dimethylformamide or dimethyl sulfoxide as an extracting agent, wherein the mass ratio of the extracting agent to an overhead is (0.5:1)-(10:1) under normal pressure or reduced pressure, and the feeding temperature of the extraction agent ranges from 20 to 40 DEG C; controlling different temperatures at the top of an extracting rectifying tower or different reflux ratios, and obtaining a dichloromethane product, a dichloromethane-methanol transition section I, a methanol product and a methanol-extracting agent transition section II from the top of the extracting rectifying tower, respectively; when the constitution of the extracting agent of a heating kettle meets the requirements, pumping the extraction agent into a high-position storage tank, and feeding materials for next batch extraction-rectification-separation. The batch extraction-rectification-separation method of the dichloromethane-methanol azeotropic mixture has the advantages that high-purity methanol and dichloromethane products are separated out by breaking the dichloromethane-methanol azeotropic system by virtue of the extracting agent, the single-tower operations are flexible, and the equipment cost is low.

Description

technical field [0001] The invention relates to a method for intermittent extraction and rectification separation of dichloromethane-methanol azeotropic mixture, which belongs to the separation technology of dichloromethane-methanol azeotropic mixture. Background technique [0002] Extractive distillation is a special distillation separation technology, which is suitable for the separation of azeotropic systems. The purpose of separation is achieved by continuously adding extractant to the top of the rectification tower to change the relative volatility between the original components. Batch extractive distillation combines the advantages of batch distillation and extractive distillation. It is flexible in operation and can separate multiple components through one tower. The equipment investment is small, and it is suitable for the separation of azeotropic and near-boiling systems in small batches. The chemical structural formula of methylene chloride is: CH 2 Cl 2 , It i...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C31/04C07C29/84C07C19/03C07C17/386
Inventor 姜占坤刘顺江孙国新
Owner UNIV OF JINAN
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