Method for recovering chloromethane from chloromethane-containing waste gas in maltol production

A technology for methyl chloride and maltol, which is applied in the field of recovering methyl chloride from methyl chloride-containing waste gas in the production of maltol, can solve problems such as unfriendly environment, and achieve the effects of reducing air pollution, effective recovery and treatment, and stable product quality.

Active Publication Date: 2013-04-17
XIAMEN OMIC BIOTECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
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AI Technical Summary

Problems solved by technology

In the current production process, there is no report on the recovery of methyl chloride in the waste gas. It is only discharged after simple

Method used

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  • Method for recovering chloromethane from chloromethane-containing waste gas in maltol production

Examples

Experimental program
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Effect test

Example Embodiment

[0021] Example 1

[0022] See figure 1 , The present invention is a process for recovering methyl chloride from waste gas containing methyl chloride produced during the production of maltol. It includes the following steps: (1) Primary alkaline washing: the vent pipe of the chlorination hydrolysis kettle and the methanol recovery secondary receiver tank The vent pipe is connected to the lower part of the primary caustic washing tower 1, and all waste gas generated during the reaction is collected into the caustic scrubbing tower 1. 800~1500L of liquid caustic soda with a concentration of more than 10% is placed in the caustic scrubbing tower 1. The liquid pump pumps the lye from the bottom to the top, sprays from top to bottom, and cleans the exhaust gas from bottom to top; (2) Buffer tank 2 collection: the gas after the preliminary alkaline washing is used in the large buffer tank 2 For collection, the size of the buffer tank 2 should be determined according to the specific air...

Example Embodiment

[0024] Example 2

[0025] Similar to Example 1, all waste gas produced by the high-temperature rearrangement of chlorination hydrolysis is collected into the primary caustic washing tower, and 15% lye is used for caustic washing. When the lye concentration drops to 12%, the replacement 100L concentration is 31% Lye; the gas after the initial alkaline washing enters the buffer tank, and the use is 30m 3 The buffer tank can recover 2 tons of methyl chloride a day; Roots blower is used to pump the gas in the buffer tank to the washing tower for water washing, and the clean water is replaced every 2h; the two-stage pickling is performed with concentrated sulfuric acid, and the concentration of first-level sulfuric acid is at More than 80%; After two-stage caustic soda is used for alkaline washing to remove residual acidic substances and water, after compressed by the gas compression body, it enters the condenser and cools into a liquid phase and then sends it to the finished product s...

Example Embodiment

[0026] Example 3

[0027] Similar to Examples 1 and 2, the difference is that 18% lye is used for alkaline washing, and the result also meets the requirements of the first-class product of the chemical industry standard HG / T 3674-2000 of the People's Republic of China.

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Abstract

The invention discloses a method for recovering chloromethane from chloromethane-containing waste gas in the maltol production and relates to the method for recovering chloromethane, and the method can be used for obtaining finished high-purity chloromethane and is simpler in process route and easy to realize. The method comprises the steps as follows: allowing the waste gas generated in the process of recovering a methanol solvent after chlorination reaction to pass through a hydrolysis kettle, and introducing the waste gas into an alkaline washing tower through a pipeline for alkaline washing; collecting the waste gas subjected to primary alkaline washing by a buffer tank; introducing the waste gas in the buffer tank into a water washing tower for water washing through a roots machine, and removing water-soluble substances; carrying out two-stage acid washing on the waste gas subjected to water washing; carrying out two-stage alkaline washing on the waste gas subjected to two-stage acid washing; and drying the waste gas subjected to two-stage alkaline washing, compressing by a compressor, cooling into a liquid phase by a condenser, and feeding into a finished product storage tank.

Description

technical field [0001] The invention relates to a method for recovering methyl chloride, in particular to a method for recovering methyl chloride from waste gas containing methyl chloride in the production of maltol. Background technique [0002] At present, maltol and ethyl maltol adopt the furfural route in industry. The production process is as follows: magnesium and alkyl halides are used to prepare Grignard reagents, and then undergo addition reaction with furfural. After the reaction is completed, furfuryl alcohol is obtained by hydrolysis with saturated ammonium chloride solution; Alcohol is reacted with chlorine gas in aqueous methanol solution, the methanol solvent is recovered after the reaction, and the crude product of maltol or ethyl maltol is obtained after neutralization with liquid caustic soda; the crude product is subjected to sublimation and ethanol recrystallization, and dried to obtain the finished product. (Refer to literature: Liao Wen'an, Total synthe...

Claims

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Application Information

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IPC IPC(8): C07C19/03C07C17/38
Inventor 黄聿凯王少培杨景祥
Owner XIAMEN OMIC BIOTECH CO LTD
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