Recovery method of monochloro methane

A recovery method, a technology of monochloromethane, applied in chemical instruments and methods, halogenated hydrocarbon preparation, organic chemistry, etc., can solve the problem of short, usually several seconds to several minutes, the adsorbent cannot be reused, and does not have the conditions for industrialization. and other problems, to reduce the pressure of environmental protection, avoid production and discharge treatment problems, and achieve good purging effect.

Inactive Publication Date: 2011-06-22
ZHEJIANG XINAN CHEM INDAL GROUP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The cycle period of pressure swing adsorption is generally very short, usually several seconds to several minutes. In such a short period of time, it is difficult for monochloromethane and other gases to penetrate the adsorbent in an orderly manner, and most of monochlor

Method used

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  • Recovery method of monochloro methane

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Effect test

Embodiment 1

[0035] The monochloromethane-containing tail gas produced by the glycine method to prepare glyphosate acid is washed by multi-tower countercurrent water to remove most of the methanol and methylal in the gas. The temperature of the washing water is controlled at 5°C and the circulation flow rate is 40m 3 / h, and then through the alkali washing tower, the circulation flow of liquid alkali is 20m 3 / h, remove the acid gas in the tail gas, the monochloromethane gas from the acid gas is firstly pressurized by the fan to about 25KPa, and then enters the molecular sieve adsorption tower from top to bottom, the adsorption temperature is controlled at 25 ℃, and it is discharged from the bottom of the adsorption tower The monochloromethane gas from which impurities have been removed is obtained at the outlet, and its moisture content is 35ppm. Use nitrogen as the regeneration gas to heat it to 250°C and enter the adsorption tower from the bottom to regenerate it. After the adsorbate is ...

Embodiment 2

[0037] The monochloromethane-containing tail gas produced by the glycine method to prepare glyphosate acid is washed with countercurrent water in three towers to remove most of the methanol and methylal in the gas. The temperature of the washing water is controlled at 50°C and the circulation flow is 10m 3 / h, and then through the alkali washing tower, the circulation flow of liquid alkali is 5m 3 / h, to remove the acid gas in the tail gas, the monochloromethane gas to remove the acid gas is first pressurized by a fan to about 20KPa, then passed through a cold dryer, cooled to 10°C, and free water is discharged, from top to bottom Enter the molecular sieve adsorption tower, control the adsorption temperature to 50°C, obtain the impurity-removed monochloromethane gas from the lower outlet of the adsorption tower, and its moisture content is 25ppm, use the raw material gas as the regeneration gas to heat to 200°C and enter the adsorption tower from the bottom, about Change to nit...

Embodiment 3

[0039] The monochloromethane-containing tail gas produced by the glycine method to prepare glyphosate acid is washed with countercurrent water in three towers to remove most of the methanol and methylal in the gas. The temperature of the washing water is controlled at 30°C and the circulation flow is 20m 3 / h, then through the alkali washing tower, the circulation flow of liquid alkali is 14m 3 / h, to remove the acid gas in the tail gas, the monochloromethane gas to remove the acid gas is first pressurized by the fan to about 25KPa, first passed through the cold dryer, cooled to 10°C, and free water is discharged, from top to bottom Enter the molecular sieve adsorption tower, control the adsorption temperature to 38°C, obtain the impurity-removed monochloromethane gas from the lower outlet of the adsorption tower, and its moisture content is 25ppm, use the raw material gas as the regeneration gas to heat to 210°C and enter the adsorption tower from the bottom, about Change to ...

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Abstract

The invention discloses a recovery method of monochloro methane, which comprises the following steps: washing tail gas which is generated in the preparation process of glyphosate acid or dimethyl phosphite, adsorbing through a molecular sieve, and condensing, wherein the adsorption temperature of the molecular sieve is 10-50 DEG C. The method disclosed by the invention effectively overcomes the defects that waste acid can be generated and an organic solvent is used in the existing technique for purifying and recovering monochloro methane. In addition, the molecular sieve selected in the invention can effectively adsorb methylal, thereby reducing a great deal of washing water and effectively relieving the pressure on environmental protection. The invention has favorable economic benefit and environmental benefit, avoids the trouble of filling concentrated sulfuric acid, lowers the cost, avoids the generation of the waste sulfuric acid, and solves the problems of emission and treatment of the waste sulfuric acid, thereby realizing environmental-protection production in deed; and meanwhile, the invention can effectively enhance the adsorption efficiency of the molecular sieve, and lower the energy consumption and production cost.

Description

technical field [0001] The invention relates to a method for recovering tail gas containing monochloromethane, in particular to a method for recovering monochloromethane from the tail gas produced in the production and purification process of glyphosate acid, dimethyl phosphite and trimethyl phosphite method. Background technique [0002] Glyphosate is the world's largest sales and fastest growing herbicide. It has excellent weeding performance and has been widely used around the world with less residue in the soil. The production of glyphosate acid mainly contains two kinds of methods at present, and a kind of is air oxidation method to produce glyphosate (IDA) method, and it is the IDA method with diethanolamine generally adopting with companies such as U.S. Monsanto as starting material; One method is that the alkyl ester method is adopted by most domestic enterprises. This method is disclosed in the document DEOLSNO.P2942898.6. This method is to dissolve paraformaldehyd...

Claims

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Application Information

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IPC IPC(8): C07C19/03C07C17/389
Inventor 王伟任不凡周曙光佘慧玲陈静章娅仙
Owner ZHEJIANG XINAN CHEM INDAL GROUP
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