A method for purifying sulfur-containing malodorous waste gas

Abstract

The invention discloses a method for purifying sulfur-containing malodorous waste gas, which relates to the technical field of environmental protection. The method comprises the following steps: firstly, adding an absorption solution into an absorption kettle, introducing a pipeline for transmitting the sulfur-containing malodorous waste gas below the liquid level of the absorption solution in the absorption kettle; then introducing the sulfur-containing malodorous waste gas, and stopping introducing the sulfur-containing malodorous waste gas after the sulfur-containing malodorous waste gas reacts with the absorption solution in the absorption kettle and no more precipitation is generated, discharging and filtering to remove solids, and collecting the obtained filtrate; after measuring the filtrate, re-adding it into the absorption kettle for continuous use, and replenishing the absorption solution; repeating S2 and S3 in sequence, and continuing to purify the sulfur-containing malodorous waste gas until the sulfur-containing malodorous waste gas is completely purified; the method for purifying the sulfur-containing malodorous waste gas can effectively remove the sulfur-containing malodorous waste gas by using a mixed solvent of ethanol and cupric chloride and a specific catalyst, and this combination can improve the reaction efficiency, so that the sulfide in the waste gas is more easily absorbed and converted.

Description

Technical Field

[0001] The invention relates to environmental protection technology, and in particular to a method for purifying and treating sulfur-containing malodorous waste gas. Background Art

[0002] Sulfur-containing malodorous gases are organic or inorganic compounds containing sulfur produced by industrial emissions, sewage treatment and natural phenomena. When released into the atmosphere, they emit a strong and unpleasant odor, which has a negative impact on air quality, ecosystems and human health, such as irritation to the eyes and respiratory tract, causing respiratory problems, and even long-term exposure may lead to chronic diseases. These gases include hydrogen sulfide, mercaptans and sulfides, and their treatment methods involve activated carbon adsorption, alkaline solution washing and incineration, but the above treatment methods have some shortcomings.

[0003] The activated carbon adsorption method can easily cause secondary air pollution in the post-treatment of waste activated carbon; the alkali washing method has a limited treatment range. For example, it is ineffective in treating sulfide waste gas, and the deep treatment of waste water or waste salt after alkali treatment of malodorous gases will also cause secondary pollution; the incineration method produces harmful sulfur dioxide gas after the sulfur compounds in the waste gas are burned, which will cause secondary pollution to the atmosphere. Summary of the invention

[0004] The purpose of the present invention is to provide a method for purifying sulfur-containing malodorous waste gas to solve the above-mentioned deficiencies in the prior art.

[0005] In order to achieve the above object, the present invention provides the following technical solution: a method for purifying sulfur-containing malodorous waste gas, comprising:

[0006] S1. First, add the absorption solution into the absorption kettle, and introduce the pipeline for transmitting the sulfur-containing odorous waste gas into the absorption kettle below the liquid level of the absorption solution;

[0007] S2, then introduce sulfur-containing odorous waste gas, and when the sulfur-containing odorous waste gas reacts with the absorption solution in the absorption kettle and no more precipitation is generated, stop introducing the sulfur-containing odorous waste gas, discharge and filter to remove solids, and collect the obtained filtrate;

[0008] S3, after measuring the filtrate, add it back into the absorption kettle for continued use, and replenish the absorption solution;

[0009] S4. Repeat S2 and S3 in sequence to continue purifying the sulfur-containing odorous waste gas until the sulfur-containing odorous waste gas is completely purified.

[0010] Furthermore, the sulfur-containing odorous waste gas described in S1 is at least one of hydrogen sulfide, sulfides, methyl mercaptan, and ethyl mercaptan.

[0011] Furthermore, the absorption solvent in S1 is a mixture of ethanol and cupric chloride, and the mass ratio of ethanol to cupric chloride is 1:0.05-0.07.

[0012] Furthermore, the absorption solvent in S1 is a mixture of a mixed solvent, cupric chloride and a catalyst, and the mass ratio of the mixed solvent, cupric chloride and the catalyst is 1:0.05 to 0.07:0.1.

[0013] Furthermore, the mixed solvent is a mixture of ethanol and a bio-based solvent, and the volume ratio of the ethanol to the bio-based solvent is 1:1.

[0014] Furthermore, the bio-based solvent is biodiesel or vegetable oil.

[0015] Furthermore, the catalyst is a supported catalyst, and the preparation method of the supported catalyst is: using metal salt and rare earth element precursor to prepare a nano-scale catalyst through a sol-gel method, and loading the nano-scale catalyst on a porous carrier to prepare a supported catalyst.

[0016] Furthermore, the metal salt is copper nitrate or zinc nitrate.

[0017] Furthermore, the rare earth element precursor is lanthanum nitrate or cerium nitrate.

[0018] Furthermore, the porous carrier is activated carbon or alumina.

[0019] Compared with the prior art, the present invention provides a method for purifying sulfur-containing malodorous waste gas. Compared with the prior art, by using a mixed solvent of ethanol and cupric chloride and a specific catalyst, pollutants such as hydrogen sulfide, sulfides, methyl mercaptans, and ethyl mercaptans in the sulfur-containing malodorous waste gas can be effectively removed. This combination can improve the reaction efficiency and make the sulfide in the waste gas more easily absorbed and converted;

[0020] Compared with the traditional chemical absorption method, the solvent and catalyst used in this method are more economical, and a large amount of chemical agents are not required during the reaction process, thereby reducing the processing cost;

[0021] This method avoids the use of a large amount of chemical agents, reduces the risk of secondary pollution, and reduces the generation of waste by recycling the absorption solution; the entire purification process is simple, easy to operate and manage;

[0022] By setting up the absorption kettle, the contact between the waste gas and the absorption solution is more complete, which improves the treatment efficiency. It is suitable for sulfur-containing odorous waste gases of different concentrations and components and has a wide range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0024] Figure 1 A schematic diagram of the overall process of a method for purifying sulfur-containing malodorous waste gas provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0026] Embodiment 1:

[0027] See also Figure 1 , a method for purifying sulfur-containing malodorous waste gas, comprising:

[0028] S1. First, add the absorption solution into the absorption kettle, and introduce the pipeline for transmitting the sulfur-containing odorous waste gas into the absorption kettle below the liquid level of the absorption solution; the sulfur-containing odorous waste gas is at least one of hydrogen sulfide, sulfides, methyl mercaptan, and ethyl mercaptan; the absorption solvent is a mixture of ethanol and copper chloride, and the mass ratio of ethanol to copper chloride is 1:0.05-0.07;

[0029] S2, then introduce sulfur-containing odorous waste gas, and when the sulfur-containing odorous waste gas reacts with the absorption solution in the absorption kettle and no more precipitation is generated, stop introducing the sulfur-containing odorous waste gas, discharge and filter to remove solids, and collect the obtained filtrate;

[0030] S3, after measuring the filtrate, add it back into the absorption kettle for continued use, and replenish the absorption solution;

[0031] S4. Repeat S2 and S3 in sequence to continue purifying the sulfur-containing odorous waste gas until the sulfur-containing odorous waste gas is completely purified.

[0032] The specific implementation method is as follows: S1, 500 kg of ethanol and 25 kg of copper chloride are mixed evenly to obtain an absorption solution; the absorption solution is added into an absorption kettle and a stirring device is started. During this process, the solution presents a unique sky blue color;

[0033] S2. Under normal temperature conditions, waste gas containing at least one of hydrogen sulfide, sulfide, methyl mercaptan, and ethyl mercaptan and having a strong malodor is guided into the absorption kettle through a specially designed pipeline, and it is ensured that the waste gas can penetrate below the liquid surface of the ethanol and copper chloride mixed solution for effective absorption and treatment. This step is crucial because it directly affects the removal efficiency of harmful substances in the waste gas.

[0034] As time goes by, when the ethanol-copper chloride solution reaches saturation with the harmful substances in the above waste gas, the color of the solution can be clearly seen to change from the initial sky blue to black through the sight glass installed on the equipment, indicating that most or even all of the target pollutants have been successfully captured. At this time, the exhaust gas and stirring operations should be stopped immediately, and then the valve at the bottom should be opened to filter out the solid impurities in the solution.

[0035] S3. The filtrate after preliminary purification needs to be re-measured and returned to the absorption kettle for recycling; if the amount of liquid is found to be insufficient, fresh ethanol and copper chloride mixed solution needs to be added until the required volume is reached in order to continue to efficiently remove sulfur-containing odorous waste gas.

[0036] S4. Repeat S2 and S3 in sequence to continue purifying the sulfur-containing odorous waste gas until the sulfur-containing odorous waste gas is completely purified.

[0037] During the whole process, operators need to closely monitor the changes of various parameters, such as temperature, pressure, exhaust gas flow rate, etc., to ensure the stability and safety of the system operation. At the same time, regular inspection and maintenance of related equipment is also one of the key factors to ensure long-term stable operation. In addition, the waste residue and wastewater generated also need to be properly handled in accordance with environmental protection requirements to avoid secondary pollution to the environment.

[0038] Embodiment 2:

[0039] See also Figure 1 , a method for purifying sulfur-containing malodorous waste gas, comprising:

[0040] S1. After 500 kg of ethanol and 30 kg of copper chloride are mixed evenly, an absorption solution is obtained; the absorption solution is added into the absorption kettle and a stirring device is started. During this process, the solution presents a unique sky blue color;

[0041] S2. Under normal temperature conditions, waste gas containing at least one of hydrogen sulfide, sulfide, methyl mercaptan, and ethyl mercaptan and having a strong malodor is guided into the absorption kettle through a specially designed pipeline, and it is ensured that the waste gas can penetrate below the liquid surface of the ethanol and copper chloride mixed solution for effective absorption and treatment. This step is crucial because it directly affects the removal efficiency of harmful substances in the waste gas.

[0042] As time goes by, when the ethanol-copper chloride solution reaches saturation with the harmful substances in the above waste gas, the color of the solution can be clearly seen to change from the initial sky blue to black through the sight glass installed on the equipment, indicating that most or even all of the target pollutants have been successfully captured. At this time, the exhaust gas and stirring operations should be stopped immediately, and then the valve at the bottom should be opened to filter out the solid impurities in the solution.

[0043] S3. The filtrate after preliminary purification needs to be re-measured and returned to the absorption kettle for recycling; if the amount of liquid is found to be insufficient, fresh ethanol and copper chloride mixed solution needs to be added until the required volume is reached in order to continue to efficiently remove sulfur-containing odorous waste gas.

[0044] S4. Repeat S2 and S3 in sequence to continue purifying the sulfur-containing odorous waste gas until the sulfur-containing odorous waste gas is completely purified.

[0045] During the whole process, operators need to closely monitor the changes of various parameters, such as temperature, pressure, exhaust gas flow rate, etc., to ensure the stability and safety of the system operation. At the same time, regular inspection and maintenance of related equipment is also one of the key factors to ensure long-term stable operation. In addition, the waste residue and wastewater generated also need to be properly handled in accordance with environmental protection requirements to avoid secondary pollution to the environment.

[0046] Embodiment three:

[0047] See also Figure 1 , a method for purifying sulfur-containing malodorous waste gas, comprising:

[0048] S1. After 500 kg of ethanol and 35 kg of copper chloride are mixed evenly, an absorption solution is obtained; the absorption solution is added into the absorption kettle and a stirring device is started. During this process, the solution presents a unique sky blue color;

[0049] S2. Under normal temperature conditions, waste gas containing at least one of hydrogen sulfide, sulfide, methyl mercaptan, and ethyl mercaptan and having a strong malodor is guided into the absorption kettle through a specially designed pipeline, and it is ensured that the waste gas can penetrate below the liquid surface of the ethanol and copper chloride mixed solution for effective absorption and treatment. This step is crucial because it directly affects the removal efficiency of harmful substances in the waste gas.

[0050] As time goes by, when the ethanol-copper chloride solution reaches saturation with the harmful substances in the above waste gas, the color of the solution can be clearly seen to change from the initial sky blue to black through the sight glass installed on the equipment, indicating that most or even all of the target pollutants have been successfully captured. At this time, the exhaust gas and stirring operations should be stopped immediately, and then the valve at the bottom should be opened to filter out the solid impurities in the solution.

[0051] S3. The filtrate after preliminary purification needs to be re-measured and returned to the absorption kettle for recycling; if the amount of liquid is found to be insufficient, fresh ethanol and copper chloride mixed solution needs to be added until the required volume is reached in order to continue to efficiently remove sulfur-containing odorous waste gas.

[0052] S4. Repeat S2 and S3 in sequence to continue purifying the sulfur-containing odorous waste gas until the sulfur-containing odorous waste gas is completely purified.

[0053] During the whole process, operators need to closely monitor the changes of various parameters, such as temperature, pressure, exhaust gas flow rate, etc., to ensure the stability and safety of the system operation. At the same time, regular inspection and maintenance of related equipment is also one of the key factors to ensure long-term stable operation. In addition, the waste residue and wastewater generated also need to be properly handled in accordance with environmental protection requirements to avoid secondary pollution to the environment.

[0054] Embodiment 4:

[0055] See also Figure 1 This embodiment provides a technical solution based on the first embodiment: a method for purifying sulfur-containing malodorous waste gas, comprising:

[0056] S1. First, add the absorption solution into the absorption kettle, and introduce the pipeline for transmitting sulfur-containing odorous waste gas into the absorption kettle below the liquid level of the absorption solution; the absorption solvent is a mixture of a mixed solvent, copper chloride and a catalyst, and the mass ratio of the mixed solvent, copper chloride and the catalyst is 1:0.05-0.07:0.1; the mixed solvent is a mixture of ethanol and a bio-based solvent, and the volume ratio of ethanol and the bio-based solvent is 1:1; the bio-based solvent is biodiesel or vegetable oil; the catalyst is a supported catalyst, and the preparation method of the supported catalyst is: using metal salts and rare earth element precursors to prepare nano-scale catalysts through a sol-gel method, and the nano-scale catalysts are loaded on a porous carrier to prepare a supported catalyst; the metal salt is copper nitrate or zinc nitrate; the rare earth element precursor is lanthanum nitrate or cerium nitrate; the porous carrier is activated carbon or alumina.

[0057] S2, then introduce sulfur-containing odorous waste gas, and when the sulfur-containing odorous waste gas reacts with the absorption solution in the absorption kettle and no more precipitation is generated, stop introducing the sulfur-containing odorous waste gas, discharge and filter to remove solids, and collect the obtained filtrate;

[0058] S3, after measuring the filtrate, add it back into the absorption kettle for continued use, and replenish the absorption solution;

[0059] S4. Repeat S2 and S3 in sequence to continue purifying the sulfur-containing odorous waste gas until the sulfur-containing odorous waste gas is completely purified.

[0060] The specific implementation method is as follows: S1. Ethanol and a bio-based solvent are uniformly mixed in a volume ratio of 1:1 to obtain a mixed solvent; the bio-based solvent can be selected from biodiesel or vegetable oil, such as soybean oil, rapeseed oil, etc. These solvents have the advantages of being renewable and environmentally friendly.

[0061] The mixed solvent, copper chloride and catalyst are mixed evenly in a mass ratio of 1:0.05 to 0.07:0.1 to obtain an absorption solvent. Among them, copper chloride, as an absorbent, can react with sulfide in sulfur-containing malodorous waste gas to generate precipitate.

[0062] Preparation of supported catalyst: dissolving copper nitrate and lanthanum nitrate in ethanol solvent respectively to form a uniform solution, wherein the concentration of the copper nitrate ethanol solution is 0.01-0.1 mol / L, and the concentration of the lanthanum nitrate ethanol solution is 0.005-0.05 mol / L;

[0063] The copper nitrate ethanol solution and the lanthanum nitrate ethanol solution are mixed in a volume ratio of 1:1, and after being evenly mixed, deionized water is added to carry out a hydrolysis reaction to generate a mixed solution of a corresponding metal salt and a hydroxyl compound of a rare earth element precursor, and the pH value of the mixed solution is adjusted to between 3 and 5 by nitric acid to promote the hydrolysis reaction.

[0064] Under the temperature condition of 60-80℃, the mixed solution is stirred to make the reaction fully proceed and form a uniform sol. The sol is left to stand at room temperature to gradually form a gel with a certain spatial structure. The formation of the gel is due to the condensation reaction of the hydroxyl compounds in the sol to form a network structure. The gel is dried at room temperature to remove the solvent and moisture.

[0065] The dried gel is calcined at a high temperature of 600-800°C to decompose organic matter and residual solvent to obtain nanoparticles of metal salt and rare earth oxide.

[0066] Activated carbon with high specific surface area and developed pore structure is selected and crushed to obtain activated carbon powder; nanoparticles of metal salt and rare earth oxide are evenly dispersed in ethanol solvent to form a catalyst solution.

[0067] The activated carbon carrier is immersed in the catalyst solution so that the catalyst is evenly loaded on the carrier surface. After the immersion, the carrier is taken out and dried at room temperature to remove the solvent. The dried carrier is calcined at a temperature of 300-500°C to firmly combine the catalyst and the carrier to obtain a supported catalyst.

[0068] S2. Introduce the pipeline of sulfur-containing odorous waste gas into the absorption kettle, and ensure that the waste gas enters from below the liquid surface of the absorption solution so that the waste gas can fully contact with the absorption solution; the sulfur-containing odorous waste gas reacts chemically with the copper chloride in the absorption solution to generate insoluble sulfide precipitation, and the catalyst accelerates the reaction rate and improves the removal efficiency of sulfide. During the reaction, the temperature and pressure in the absorption kettle should be controlled to ensure the smooth progress of the reaction; when the sulfur-containing odorous waste gas reacts with the absorption solution and no precipitation is generated, it means that the sulfide has been basically removed. At this time, stop passing the sulfur-containing odorous waste gas, and use filtering equipment (such as plate and frame filter press, vacuum filter, etc.) to filter the absorption solution after discharging to remove the generated solid precipitate.

[0069] S3, collecting the filtrate after filtration, the filtrate contains unreacted absorption solvent and catalyst, which can be used for subsequent exhaust gas absorption; the collected filtrate is added back into the absorption kettle, and the absorption solution is supplemented according to the loss of the filtrate to maintain the concentration and volume of the absorption solution in the absorption kettle;

[0070] S4. Repeat S2 and S3 in sequence to continue purifying the sulfur-containing odorous waste gas until the sulfur-containing odorous waste gas is completely purified.

[0071] The above description is only by way of illustration of certain exemplary embodiments of the present invention. It is undoubted that those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A method for purifying sulfur-containing malodorous waste gas, characterized in that: include: S1. First, add the absorption solution into the absorption kettle, and introduce the pipeline for transmitting the sulfur-containing odorous waste gas into the absorption kettle below the liquid level of the absorption solution; S2, then introduce sulfur-containing odorous waste gas, and when the sulfur-containing odorous waste gas reacts with the absorption solution in the absorption kettle and no more precipitation is generated, stop introducing the sulfur-containing odorous waste gas, discharge and filter to remove solids, and collect the obtained filtrate; S3, after measuring the filtrate, add it back into the absorption kettle for continued use, and replenish the absorption solution; S4. Repeat S2 and S3 in sequence to continue purifying the sulfur-containing odorous waste gas until the sulfur-containing odorous waste gas is completely purified.

2. The method for purifying sulfur-containing malodorous waste gas according to claim 1, characterized in that: The sulfur-containing malodorous waste gas described in S1 is at least one of hydrogen sulfide, sulfides, methyl mercaptan, and ethyl mercaptan.

3. The method for purifying sulfur-containing malodorous waste gas according to claim 1, characterized in that: S1 The absorption solvent is a mixture of ethanol and cupric chloride, and the mass ratio of ethanol to cupric chloride is 1:0.05-0.

07.

4. The method for purifying sulfur-containing malodorous waste gas according to claim 1, characterized in that: S1 The absorption solvent is a mixture of a mixed solvent, copper chloride and a catalyst, and the mass ratio of the mixed solvent, copper chloride and the catalyst is 1:0.05 to 0.07:0.

1.

5. The method for purifying sulfur-containing malodorous waste gas according to claim 4, characterized in that: The mixed solvent is a mixture of ethanol and a bio-based solvent, and the volume ratio of the ethanol to the bio-based solvent is 1:

1.

6. The method for purifying sulfur-containing malodorous waste gas according to claim 5, characterized in that: The bio-based solvent is biodiesel or vegetable oil.

7. The method for purifying sulfur-containing malodorous waste gas according to claim 4, characterized in that: The catalyst is a supported catalyst, and the preparation method of the supported catalyst is: using metal salt and rare earth element precursor to prepare a nano-scale catalyst through a sol-gel method, and loading the nano-scale catalyst on a porous carrier to prepare a supported catalyst.

8. The method for purifying sulfur-containing malodorous waste gas according to claim 7, characterized in that: The metal salt is copper nitrate or zinc nitrate.

9. The method for purifying sulfur-containing malodorous waste gas according to claim 1, characterized in that: The rare earth element precursor is lanthanum nitrate or cerium nitrate.

10. The method for purifying sulfur-containing malodorous waste gas according to claim 1, characterized in that: The porous carrier is activated carbon or alumina.

Images