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
  • Application Information

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 treatment, which is very unfriendly to the environment. Therefore, we are committed to establishing a device for recovering methyl chloride.

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

Embodiment 1

[0022] see figure 1 , the present invention is a process for recovering methyl chloride from methane chloride waste gas produced in the production process of maltol, including the following steps: (1) primary alkali washing: the vent pipe of the chlorination hydrolysis kettle and the secondary receiving tank for methanol recovery The emptying pipe of the outlet is connected to the middle and lower part of the primary alkali washing tower 1, and all waste gas generated during the reaction is collected into the alkali washing tower 1, and 800~1500L liquid caustic soda with a concentration of 10% or more is placed in the alkali washing 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 preliminary alkali washing is used in a large buffer tank 2 For collection, the size of the buffer tank 2 should be determined according to the specific air flow; (3...

Embodiment 2

[0025] Similar to Example 1, all waste gas generated by chlorination hydrolysis high-temperature rearrangement is collected into the primary alkali washing tower, and 15% lye is used for alkali washing. When the concentration of lye drops to 12%, the concentration of 100L of replacement is 31%. lye; the gas after preliminary alkali washing enters the buffer tank, using 30m 3 The buffer tank can recover 2 tons of methyl chloride a day; use Roots blower to pump the gas in the buffer tank to the water washing tower for washing, and replace the clean water every 2 hours; use concentrated sulfuric acid for two-stage pickling, the concentration of the first-stage sulfuric acid is at More than 80%; and then go through two-stage caustic soda for alkali washing to remove residual acidic substances and water. After being compressed by the gas compression body, it enters the condenser to be cooled into a liquid phase and then sent to the finished product storage tank.

Embodiment 3

[0027] Similar to Examples 1 and 2, the difference is that 18% lye is used for alkaline washing, and the results also meet 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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