Resource utilization and treatment method for nitromethane waste gas

A technology of nitromethane and resource utilization, which is applied in the field of resource utilization and treatment of nitromethane waste gas. It can solve the problems of reducing nitrogen oxide emissions and purifying harmful waste gas methyl nitrite, so as to reduce emissions and realize green environmental protection. Emissions and the effect of avoiding waste of resources

Active Publication Date: 2021-06-18
HUBEI FUBO CHEM & IND CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0007] The invention provides a treatment method for resource utilization of nitromethane waste gas, which solves the purification of harmful waste gas methyl nitrite in the production process of nitromethane in the prior art, reduces the emission of nitrogen oxides in tail gas, and quickly treats nitromethane Exhaust technical problems

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  • Resource utilization and treatment method for nitromethane waste gas
  • Resource utilization and treatment method for nitromethane waste gas

Examples

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Embodiment 1

[0096] A kind of purification method of nitromethane tail gas of the present invention, comprises the following steps:

[0097] (1) The nitromethane waste gas produced by the industry through the substitution reaction of dimethyl sulfate and sodium nitrite is washed successively by sodium carbonate solution with pH=9 and sodium hydroxide solution with pH=11, keeping the washing temperature at 0°C;

[0098](2) Pass the tail gas washed by the two-stage lye successively into the absorption solution of absolute ethanol whose molar ratio of sodium hydroxide and hydrazine hydrate is 1.05:1 for reaction and absorption, the temperature of the absorption reaction is 18°C, and the stirring speed is 140r / min, control the pH of the absorbing liquid>9, when the pH=9.3, end the absorption reaction of this batch of absorbing liquid, switch to another absorbing liquid containing hydrazine hydrate and sodium hydroxide absolute ethanol for tail gas absorption, and switch Filter the reaction so...

Embodiment 2

[0100] A kind of purification method of nitromethane tail gas of the present invention, comprises the following steps:

[0101] (1) The nitromethane waste gas produced by industry through the substitution reaction of dimethyl sulfate and sodium nitrite is washed successively by the sodium carbonate solution washing of pH=8.5 and the mixed solution washing of sodium bicarbonate and sodium hydroxide of pH=10, keeping The washing temperature is 45°C;

[0102] (2) Pass the tail gas washed by two-stage lye successively into the absorption solution of anhydrous methanol with a molar ratio of sodium hydroxide and hydrazine hydrate of 1.1:1 for reaction and absorption, the temperature of the absorption reaction is 40°C, and the stirring speed is 120r / min, control the pH of the absorption liquid>9, when the pH=9.35, end the absorption reaction of this batch of absorption liquid, switch to another absorption liquid containing hydrazine hydrate sodium hydroxide anhydrous methanol and th...

Embodiment 3

[0104] (1) the tail gas of the nitromethane produced by industry through the substitution reaction of dimethyl sulfate and sodium nitrite is washed successively by the mixed solution washing of sodium carbonate and sodium hydroxide of pH=9.5 and the washing of sodium hydroxide solution of pH=12, Keep the washing temperature at 20°C;

[0105] (2) Pass the tail gas washed by two-stage lye successively into the absorption solution of anhydrous methanol with a molar ratio of sodium hydroxide and hydrazine hydrate of 1.25:1 for reaction and absorption, the temperature of the absorption reaction is 25°C, and the stirring speed is 80r / min, control the pH of the absorption liquid>9, when pH=9.05, end the absorption reaction of this batch of absorption liquid, switch to another absorption liquid containing hydrazine hydrate sodium hydroxide anhydrous methanol and then carry out tail gas absorption, will switch The obtained reaction solution is filtered, the filtered mother liquor is s...

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Abstract

The invention belongs to the technical field of environment-friendly waste gas treatment, and particularly discloses a nitromethane waste gas recycling treatment method. According to a technical scheme in the invention, the method comprises the following steps: (1) washing the nitromethane waste gas through multi-stage alkali liquor in sequence; and (2) introducing tail gas washed by the multi-stage alkali liquor into absorption liquid of a sodium hydroxide or potassium hydroxide organic solvent containing hydrazine hydrate for reaction absorption. The invention also provides a method for preparing sodium azide or potassium azide and a medical intermediate methylmercaptotetrazole by using the nitromethane tail gas. The method is different from an existing method which only uses alkali liquor for absorption treatment; and according to the method, the waste gas is purified through multi-stage alkali liquor washing, then methyl nitrite causing excessive emission of nitric oxide is subjected to reaction absorption, efficient co-production can be achieved while the waste gas is treated, the waste is turned into the wealth, and problems in treatment of nitrogen oxides in continuous large-scale production of nitromethane are solved.

Description

technical field [0001] The invention belongs to the technical field of environmental protection waste gas treatment, and in particular relates to a treatment method for resource utilization of nitromethane waste gas. Background technique [0002] At present, domestic industrial production of nitromethane generally adopts the substitution reaction of dimethyl sulfate and sodium nitrite to synthesize. The advantage of this synthesis process is that the reaction conditions are relatively mild and the product purity is high, but there are also low reaction yields and by-products (exhaust gas) ) many, the shortcoming that exhaust gas treatment is difficult. With the continuous strengthening of national environmental protection awareness and the continuous strengthening of national environmental protection policies and environmental protection law enforcement, the scientific treatment of waste gas in the production of nitromethane has increasingly become a bottleneck affecting the...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D53/75B01D53/78B01D53/62B01D53/72C07D257/04C01B21/08
CPCB01D53/75B01D53/78B01D53/62B01D53/72C07D257/04C01B21/08B01D2257/504B01D2251/80B01D2251/604B01D2251/304B01D2251/306B01D2251/606C01P2006/80
Inventor 雷大有李焰杨长云田童
Owner HUBEI FUBO CHEM & IND CO LTD
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