阅读说明：本技术 一种低氮氧化物排放量的焦亚硫酸钠的生产方法 (Production method of sodium metabisulfite with low nitrogen oxide emission ) 是由 汪伟国 张维帮 于 2020-11-11 设计创作，主要内容包括：本发明公开了一种低氮氧化物排放量的焦亚硫酸钠的生产方法,包括步骤：S1：将硫磺粉末送入低氮燃烧炉中,于600~1100℃下进行自燃,得到二氧化硫气体；S2：将二氧化硫气体经过除尘处理后通入三级反应器中与纯碱溶液发生中和反应,反应生成焦亚硫酸钠悬浮液；S3：步骤S2所述的焦亚硫酸钠悬浮液经过二级反应器、一级反应器生成焦亚硫酸钠结晶,将所述的焦亚硫酸钠结晶在150~180℃下干燥后即可得到成品；S4：步骤S2中产生的尾气由碱液吸收塔处理除去二氧化硫后,经加压装置压缩后通入转化塔内进行氮氧化物吸收处理后由排气口排出。本发明降低了焦亚硫酸钠生产过程中的氮氧化物的排放量,降低了对环境的污染,减少了硫磺的消耗量,节约了原料成本。(The invention discloses a production method of sodium metabisulfite with low emission of nitrogen oxides, which comprises the following steps: s1: feeding sulfur powder into a low-nitrogen combustion furnace, and carrying out spontaneous combustion at 600-1100 ℃ to obtain sulfur dioxide gas; s2: introducing the sulfur dioxide gas subjected to dust removal treatment into a three-stage reactor to perform a neutralization reaction with a soda solution, and reacting to generate a sodium metabisulfite suspension; s3: the sodium metabisulfite suspension liquid obtained in the step S2 is processed by a secondary reactor and a primary reactor to generate sodium metabisulfite crystals, and the sodium metabisulfite crystals are dried at the temperature of 150-180 ℃ to obtain a finished product; s4: and (4) treating the tail gas generated in the step (S2) by an alkali liquor absorption tower to remove sulfur dioxide, compressing the tail gas by a pressurizing device, introducing the compressed tail gas into a conversion tower to carry out nitrogen oxide absorption treatment, and discharging the tail gas from an exhaust port. The invention reduces the discharge amount of nitrogen oxides in the production process of sodium metabisulfite, reduces the pollution to the environment, reduces the consumption of sulfur and saves the cost of raw materials.)

1. A production method of sodium metabisulfite with low emission of nitrogen oxides comprises the following steps:

s1: feeding sulfur powder into a low-nitrogen combustion furnace, and carrying out spontaneous combustion at 600-1100 ℃ to obtain sulfur dioxide gas;

s2: introducing the sulfur dioxide gas subjected to dust removal treatment into a three-stage reactor to perform a neutralization reaction with a soda solution, and reacting to generate a sodium metabisulfite suspension;

s3: the sodium metabisulfite suspension liquid obtained in the step S2 is processed by a secondary reactor and a primary reactor to generate sodium metabisulfite crystals, and the sodium metabisulfite crystals are dried at the temperature of 150-180 ℃ to obtain a finished product;

s4: and (4) treating the tail gas generated in the step (S2) by an alkali liquor absorption tower to remove sulfur dioxide, compressing the tail gas by a pressurizing device, introducing the compressed tail gas into a conversion tower to carry out nitrogen oxide absorption treatment, and discharging the tail gas from an exhaust port.

2. The method for producing sodium metabisulfite with low emission of nitrogen oxides as claimed in claim 1, wherein the method comprises the following steps: step S1 is to charge oxygen into the low-nitrogen combustion furnace before introducing sulfur powder to reduce the content of nitrogen in the low-nitrogen combustion furnace.

3. The method for producing sodium metabisulfite with low emission of nitrogen oxides as claimed in claim 1, wherein the method comprises the following steps: the low-nitrogen combustion furnace of step S1 includes a plurality of gas distribution devices disposed in the furnace body of the low-nitrogen combustion furnace, a cooling hood disposed at the top of the low-nitrogen combustion furnace, and a gas outlet.

4. The method for producing sodium metabisulfite with low emission of nitrogen oxides as claimed in claim 1, wherein the method comprises the following steps: the gas distribution device is provided with a plurality of combustion nozzles.

5. The method for producing sodium metabisulfite with low emission of nitrogen oxides as claimed in claim 1, wherein the method comprises the following steps: in the neutralization reaction in the step S2, the gas concentration of sulfur dioxide is 10-15%.

6. The method for producing sodium metabisulfite with low emission of nitrogen oxides as claimed in claim 1, wherein the method comprises the following steps: the temperature of the sulfur dioxide introduced in the step S2 is 51-60 ℃.

7. The method for producing sodium metabisulfite with low emission of nitrogen oxides as claimed in claim 1, wherein the method comprises the following steps: and step S4, arranging a nitrogen oxide online detection device at the exhaust port of the conversion tower.

8. The method for producing sodium metabisulfite with low emission of nitrogen oxides as claimed in claim 1, wherein the method comprises the following steps: the conversion tower of the step S4 comprises a dispersing device, wherein the dispersing device comprises a spraying pipeline for spraying absorption liquid and an aeration pipeline for uniformly distributing waste gas containing nitrogen oxides, and the spraying pipeline and the aeration pipeline are distributed in the dispersing device in a staggered manner.

9. The method for producing sodium metabisulfite with low emission of nitrogen oxides as claimed in claim 8, wherein the method comprises the following steps: the absorption liquid is one of an acidic solution of urea, ammonium carbonate, ammonium bicarbonate, ammonium chloride or tributyl phosphate.

Technical Field

The invention relates to the technical field of chemical synthesis, in particular to a production method of sodium metabisulfite with low nitrogen oxide emission.

Background

Sodium metabisulfite, also known as sodium metabisulfite, is a white or yellow crystalline powder or small crystal, an important sulfite. In the food industry as bleaching agents, preservatives, bulking agents, antioxidants, colour protection agents and preservatives; chloroform, phenyl sulfone and benzaldehyde are produced in the pharmaceutical industry; the textile industry is used as dechlorinating agent and cotton scouring assistant after cotton cloth bleaching. The leather-making industry is used for leather treatment, and can make leather soft, plump and tough, and has the properties of water resistance, folding resistance, wear resistance and the like. The chemical industry is used for producing hydroxy vanillin, hydroxylamine hydrochloride and the like. The photosensitive industry is used as developers and the like.

The specific method for preparing the sodium metabisulfite by the wet method with the sulfur as the raw material comprises the following steps: adding a certain amount of soda ash into sodium bisulfite solution to generate suspension of sulfurous acid, then introducing sulfur dioxide to generate sodium metabisulfite crystal, centrifugally separating and drying to obtain the finished product. The sulfur dioxide is prepared by burning sulfur at 600-1100 ℃, and due to the fact that the burning temperature is too high, sulfur steam or sublimed sulfur generated in the combustion process of the sulfur has catalytic oxidation performance, nitrogen in air is oxidized to generate nitrogen oxide such as nitric oxide and nitrogen dioxide, the generated nitrogen oxide enters the synthesis process of sodium metabisulfite along with the sulfur dioxide and is finally discharged into the atmosphere along with tail gas, and although the content of the nitrogen oxide is relatively low, the requirement of increasingly severe emission standards is difficult to achieve. Most of waste gas treatment processes in sodium metabisulfite production processes in the prior art aim at sulfur dioxide, and researches on reducing the emission of nitrogen oxides in sodium metabisulfite production are rarely reported. The emission reduction method of nitrogen oxides in the prior art mainly comprises a selective catalytic reduction method (SCR method) and a selective non-catalytic reduction method (SNCR method). The SCR method takes ammonia or urea as an absorption liquid, and converts nitrogen oxide into nitrogen under the action of a catalyst with the component of V, W, Ti, so that the method has good denitration effect, but has the problem of ammonia escape and is extremely easy to cause secondary pollution to the environment; the SNCR method also takes ammonia or urea as an absorption liquid, converts nitrogen oxides into nitrogen under the condition of not needing a catalyst, and has low denitration efficiency, narrow window temperature of effective reaction and difficult control. In conclusion, how to provide a production method of sodium metabisulfite with low nitrogen oxide emission becomes a difficult problem to be solved urgently.

Disclosure of Invention

The invention aims to solve the problems and provide a method for producing sodium metabisulfite with high degradation efficiency, simple and convenient operation and low nitrogen oxide emission, which is easy to operate.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

a production method of sodium metabisulfite with low emission of nitrogen oxides comprises the following steps:

s1: feeding sulfur powder into a low-nitrogen combustion furnace, and carrying out spontaneous combustion at 600-1100 ℃ to obtain sulfur dioxide gas;

s2: introducing the sulfur dioxide gas subjected to dust removal treatment into a three-stage reactor to perform a neutralization reaction with a soda solution, and reacting to generate a sodium metabisulfite suspension;

s3: the sodium metabisulfite suspension liquid obtained in the step S2 is processed by a secondary reactor and a primary reactor to generate sodium metabisulfite crystals, and the sodium metabisulfite crystals are dried at the temperature of 150-180 ℃ to obtain a finished product;

s4: and (4) treating the tail gas generated in the step (S2) by an alkali liquor absorption tower to remove sulfur dioxide, compressing the tail gas by a pressurizing device, introducing the compressed tail gas into a conversion tower to carry out nitrogen oxide absorption treatment, and discharging the tail gas from an exhaust port.

On the one hand, the invention takes the production method of sodium metabisulfite in the prior art as the basis, and controls the generation amount of nitrogen oxides from the source when a low-nitrogen combustion furnace with low nitrogen oxide generation is used as a combustion furnace of sulfur; on the other hand, a conversion tower for degrading the nitrogen oxides is arranged, the nitrogen oxides are discharged after being converted into nitrogen through absorption, and the lower discharge amount of the nitrogen oxides is further ensured.

Preferably, step S1 is to charge oxygen into the low-nitrogen combustion furnace before introducing sulfur powder to reduce the content of nitrogen in the low-nitrogen combustion furnace.

Preferably, the low-nitrogen combustion furnace in step S1 includes a plurality of gas distribution devices disposed in the furnace body of the low-nitrogen combustion furnace, a cooling hood disposed at the top of the low-nitrogen combustion furnace, and a gas outlet.

Preferably, a plurality of combustion nozzles are arranged on the gas distribution device.

Preferably, in the neutralization reaction in the step S2, the gas concentration of the sulfur dioxide is 10-15%.

Preferably, the temperature of the introduced sulfur dioxide in the step S2 is 51-60 ℃.

Preferably, an online nitrogen oxide detection device is arranged at the exhaust port of the conversion tower in the step S4.

Preferably, the conversion tower of step S4 is provided with a dispersing device, the dispersing device comprises a spraying pipe for spraying the absorption liquid and an aeration pipe for uniformly distributing the waste gas containing nitrogen oxides, and the spraying pipe and the aeration pipe are distributed in the dispersing device in a staggered manner.

Preferably, the absorption liquid is one of an acidic solution of urea, ammonium carbonate, ammonium bicarbonate, ammonium chloride or tributyl phosphate.

Preferably, a pressurizing valve is arranged in the aeration pipeline.

The invention has the following beneficial effects:

1. the invention discloses a production method of sodium metabisulfite with low emission of nitrogen oxides, which combines a low-nitrogen combustion furnace and a conversion tower to control the generation amount of the nitrogen oxides and reduce the nitrogen oxides in combination with the nitrogen oxides generated in the production process of the sodium metabisulfite, thereby reducing the emission of the nitrogen oxides in the production process of the sodium metabisulfite and reducing the pollution to the environment.

2. The cooling cover is arranged in the low-nitrogen combustion furnace, and the temperature of the top of the low-nitrogen combustion furnace is reduced by the cooling cover, so that sublimed sulfur generated in the combustion process of sulfur is cooled and solidified into sulfur powder, and the sulfur powder is continuously combusted to generate sulfur dioxide gas, so that the catalytic performance of nitrogen oxidation is reduced, the consumption of sulfur is reduced, the combustion efficiency of sulfur is increased, and the raw material cost is saved.

3. The gas distribution device is provided with a plurality of combustion nozzles, large-volume combustion flame with gathering property generated by the sulfur combustion chamber is converted into a plurality of small combustion points, so that the sulfur is fully combusted, high-temperature areas generated by gathering of large-group flame are reduced, and the possibility of oxidizing nitrogen into nitrogen oxide is further reduced.

4. The tail gas generated by the invention is treated by the alkali liquor absorption tower to remove sulfur dioxide, then is compressed by the pressurizing device and then is introduced into the conversion tower for absorbing nitrogen oxides, so that the content of the nitrogen oxides in the unit volume of the waste gas introduced into the conversion tower is improved after compression, convenience is provided for capturing and absorbing the nitrogen oxides by the absorption liquid, and the absorption efficiency is accelerated.

5. The absorption tower provided by the invention adopts a liquid absorption method to absorb nitrogen oxides, so that the absorption efficiency is high and secondary pollution is not easy to generate.

Drawings

FIG. 1 is a schematic view of a low nitrogen combustion furnace;

FIG. 2 is a schematic diagram of an absorption column;

wherein, 1 is a low-nitrogen combustion furnace, 11 is a gas distribution device, 111 is a combustion nozzle, 12 is a cooling cover, 13 is an air outlet, 2 is an absorption tower, 21 is a spray pipeline, and 22 is an aeration pipeline.

Detailed Description

The present invention will be described in further detail with reference to specific examples.

In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

Example 1

A production method of sodium metabisulfite with low emission of nitrogen oxides comprises the following steps:

s1: and (3) feeding the sulfur powder into a low-nitrogen combustion furnace, and carrying out spontaneous combustion at 600 ℃ to obtain sulfur dioxide gas.

S2: introducing the sulfur dioxide gas subjected to dust removal treatment into a three-stage reactor to perform a neutralization reaction with a soda solution, and reacting to generate a sodium metabisulfite suspension; the gas concentration of the sulfur dioxide is 10%, the adding amount of the oxygen is 2 times of the theoretical amount, and the introducing temperature of the sulfur dioxide is 51 ℃.

S3: and S2, the sodium metabisulfite suspension is processed by a secondary reactor and a primary reactor to generate sodium metabisulfite crystals, and the sodium metabisulfite crystals are dried at 150 ℃ to obtain a finished product.

S4: and (4) treating the tail gas generated in the step (S2) by an alkali liquor absorption tower to remove sulfur dioxide, compressing the tail gas by a pressurizing device, introducing the compressed tail gas into a conversion tower to carry out nitrogen oxide absorption treatment, and discharging the tail gas from an exhaust port. And a nitrogen oxide online detection device is arranged at an exhaust port of the conversion tower.

Step S1 is to charge oxygen into the low-nitrogen combustion furnace before introducing sulfur powder to reduce the content of nitrogen in the low-nitrogen combustion furnace.

Fig. 1 is a schematic view of the low-nitrogen combustion furnace, and as shown in fig. 1, the low-nitrogen combustion furnace 1 comprises a plurality of gas distribution devices 11 arranged in a furnace body of the low-nitrogen combustion furnace, a cooling hood 12 arranged at the top of the low-nitrogen combustion furnace and a gas outlet 13; the gas distribution device is provided with a plurality of combustion nozzles 111.

Fig. 2 is a schematic view of the dispersing device, and as shown in fig. 2, the dispersing device 2 comprises a dispersing device which comprises a spraying pipe 21 for spraying an absorption liquid and an aeration pipe 22 for uniformly distributing waste gas containing nitrogen oxides, and the spraying pipe and the aeration pipe are distributed in the dispersing device in a staggered manner.

The absorption liquid is an acidic aqueous solution of urea, namely sulfuric acid is used as an acidic solvent, the absorption treatment temperature is 30-90 ℃, and the pH value is 1-3; finally, the nitrogen oxides are converted into carbon dioxide, nitrogen and water. The online detection device is used for detecting the discharge amount of nitrogen oxides to be 30 mg/m.

Example 2

A production method of sodium metabisulfite with low emission of nitrogen oxides comprises the following steps:

s1: and (3) feeding the sulfur powder into a low-nitrogen combustion furnace, and carrying out spontaneous combustion at 800 ℃ to obtain sulfur dioxide gas.

S2: introducing the sulfur dioxide gas subjected to dust removal treatment into a three-stage reactor to perform a neutralization reaction with a soda solution, and reacting to generate a sodium metabisulfite suspension; the gas concentration of the sulfur dioxide is 12 percent, and the temperature of introducing the sulfur dioxide is 55 ℃.

S3: and (S2) the sodium metabisulfite suspension is processed by a secondary reactor and a primary reactor to generate sodium metabisulfite crystals, and the sodium metabisulfite crystals are dried at 170 ℃ to obtain a finished product.

S4: and (4) treating the tail gas generated in the step (S2) by an alkali liquor absorption tower to remove sulfur dioxide, compressing the tail gas by a pressurizing device, introducing the compressed tail gas into a conversion tower to carry out nitrogen oxide absorption treatment, and discharging the tail gas from an exhaust port. And a nitrogen oxide online detection device is arranged at an exhaust port of the conversion tower.

The absorption liquid is tributyl phosphate, and the absorption treatment comprises the following specific steps: firstly, the waste gas containing nitrogen oxides is introduced into the conversion tower through the aeration pipeline, so that the waste gas is in contact with the air in the conversion tower to convert the nitric oxide into nitrogen dioxide, then the absorption liquid is sprayed out from the spraying pipeline to absorb and degrade the nitrogen oxides, and finally the nitrogen oxides are converted into nitrogen. The online detection device is used for detecting the emission of nitrogen oxides to be 36 mg/m.

Example 3

A production method of sodium metabisulfite with low emission of nitrogen oxides comprises the following steps:

s1: and (3) feeding the sulfur powder into a low-nitrogen combustion furnace, and carrying out spontaneous combustion at 1100 ℃ to obtain sulfur dioxide gas.

S2: introducing the sulfur dioxide gas subjected to dust removal treatment into a three-stage reactor to perform a neutralization reaction with a soda solution, and reacting to generate a sodium metabisulfite suspension; the gas concentration of the sulfur dioxide is 15%, and the temperature of introducing the sulfur dioxide is 60 ℃.

S3: and (S2) the sodium metabisulfite suspension is processed by a secondary reactor and a primary reactor to generate sodium metabisulfite crystals, and the sodium metabisulfite crystals are dried at 180 ℃ to obtain a finished product.

S4: and (4) treating the tail gas generated in the step (S2) by an alkali liquor absorption tower to remove sulfur dioxide, compressing the tail gas by a pressurizing device, introducing the compressed tail gas into a conversion tower to carry out nitrogen oxide absorption treatment, and discharging the tail gas from an exhaust port. And a nitrogen oxide online detection device is arranged at an exhaust port of the conversion tower.

The absorption liquid is an ammonium bicarbonate solution with the concentration of 20-50%, the reaction temperature is 800-850 ℃, and finally nitrogen oxides are converted into nitrogen, water and carbon dioxide. The online detection device is used for detecting the emission of nitrogen oxides and is 40 mg/m in high-speed dry-method cultivation.

In examples 1-3, the emission measured by the online detection device for nitrogen oxides is less than 50 mg/m, and is much less than the specified emission value of less than or equal to 100mg/m for cultivation according to national standard GB 31573 and 2015 emission Standard for pollutants for inorganic chemical industry.

The above-described preferred embodiments of the present invention are not intended to limit the present invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the claims of the present invention.