CN112426878A - Method and system for catalytic degradation of nitrogen/sulfur-containing VOCs (volatile organic compounds) by absorption and liquid phase - Google Patents

Method and system for catalytic degradation of nitrogen/sulfur-containing VOCs (volatile organic compounds) by absorption and liquid phase Download PDF

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CN112426878A
CN112426878A CN202011138689.6A CN202011138689A CN112426878A CN 112426878 A CN112426878 A CN 112426878A CN 202011138689 A CN202011138689 A CN 202011138689A CN 112426878 A CN112426878 A CN 112426878A
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absorption
sulfur
nitrogen
liquid
molecular sieve
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吴忠标
张天昱
刘越
王岳军
高珊
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Zhejiang University ZJU
Zhejiang Tianlan Environmental Protection Technology Co Ltd
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Zhejiang University ZJU
Zhejiang Tianlan Environmental Protection Technology Co Ltd
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
    • B01D53/86—Catalytic processes
    • B01D53/8621—Removing nitrogen compounds
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/007—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by irradiation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
    • B01D53/86—Catalytic processes
    • B01D53/8603—Removing sulfur compounds
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2257/00—Components to be removed
    • B01D2257/70—Organic compounds not provided for in groups B01D2257/00 - B01D2257/602
    • B01D2257/708—Volatile organic compounds V.O.C.'s
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2259/00—Type of treatment
    • B01D2259/80—Employing electric, magnetic, electromagnetic or wave energy, or particle radiation
    • B01D2259/804—UV light

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Abstract

The invention discloses a method and a system for degrading nitrogen/sulfur-containing VOCs by absorption and liquid phase catalysis. The method comprises the following steps: the waste gas containing nitrogen/sulfur-containing VOCs passes through an absorption liquid containing an HZSM-5 molecular sieve under ultraviolet light to complete the degradation of the nitrogen/sulfur-containing VOCs; the silicon-aluminum molar ratio of the HZSM-5 molecular sieve is 18-360: 1; the pH value of the absorption liquid is 3-8; the concentration of the HZSM-5 molecular sieve in the absorption liquid is 0.1-5 g/L. The system comprises a liquid-phase absorption-catalysis device filled with the absorption liquid; an air inlet pipe with one closed end and the other end for nitrogen/sulfur-containing VOCs waste gas to enter is arranged in the liquid phase absorption-catalysis device and close to the bottom, a plurality of aeration pipes with one closed end are arranged on two sides of the air inlet pipe at intervals, and aeration holes are formed in the bottoms of the aeration pipes; an ultraviolet lamp is arranged above the air inlet pipe in the liquid phase absorption-catalysis device.

Description

Method and system for catalytic degradation of nitrogen/sulfur-containing VOCs (volatile organic compounds) by absorption and liquid phase
Technical Field
The invention relates to the technical field of environmental catalysis, in particular to a method and a system for catalytic degradation of nitrogen/sulfur-containing VOCs by absorption and liquid phase.
Background
In recent years, the economy of China is rapidly developed, the industrialization level is continuously improved, the living standard of residents is greatly improved, and meanwhile, the problem of air pollution is more and more serious. Among them, Volatile Organic Compounds (VOCs) containing nitrogen and sulfur, which are discharged during urban public construction such as sewage treatment, garbage transfer and treatment, livestock and poultry breeding, pharmaceutical production, chemical production and the like, have serious influence on the surrounding environment and the health of people. The VOCs not only have high toxicity, but also have odor such as methyl mercaptan (CH)3SH), thiodimethyl ether (C)2H6S), trimethylamine (C)3H9N) etc. are very low. Therefore, the method has very important practical significance for the advanced treatment of the low-concentration nitrogen-containing and sulfur-containing VOCs.
At present, the common treatment method for the gas containing the VOCs comprises the following steps: physical, chemical, biological, catalytic combustion. Physical and chemical methods can purify gas containing target pollutants, but the energy consumption and the operation cost are high, and the regeneration and post-treatment processes of the adsorbent are complicated and easily cause secondary pollution. The biological method can be used for treating VOCs with low concentration and good biodegradability, but has the defects of large occupied area, high investment cost, poor impact load resistance and difficult treatment of VOCs with high biological toxicity. The catalytic combustion method is the most effective VOCs treatment technology at present, but the treatment of the low-concentration nitrogen-containing and sulfur-containing waste gas has the defects of high energy consumption, catalyst poisoning and NOx、SO2Secondary pollution and the like. Therefore, it is highly desirable to develop a low-cost technology capable of deeply treating large-volume low-concentration nitrogen-containing and sulfur-containing VOCs waste gas.
Patent specification with publication number CN107497478A discloses a catalyst for removing VOCs by ultraviolet light catalysis and a preparation method thereof. According to the patent technical content, the key of the catalyst for removing VOCs is as follows: 1. an active component having a high light utilization efficiency; 2. and carrying out ultraviolet light catalysis on the surface of the solid-phase catalyst by the gas-phase VOCs. That is, the catalyst is essentially a photocatalyst, and the invention concept and key point for solving the technical problem and removing the VOCs are to utilize a gas-solid interface to make the gaseous VOCs perform photocatalytic degradation on the surface of the solid active component under the action of ultraviolet light. In addition, in the patent technology, the carrier in the catalyst only plays a role of loading the active component, and no other role is described. Moreover, according to the description of the technology of this patent, the active ingredient is "back-coated" outside the support, so that the support cannot be directly exposed to ultraviolet light due to the blocking of the active ingredient.
Advanced Oxidation Processes (AOPs) are those in which ultraviolet light, O, is passed through3And electrochemical activation means to generate free radicals with strong oxidizing ability such as OH in liquid phase, so as to oxidize the organic matter with high molecular weight and difficult degradation into low-toxic or non-toxic small molecular weight substance. The technology is widely applied in the field of sewage treatment, and has the advantages of high efficiency, low cost, wide application range and the like.
Disclosure of Invention
Aiming at the defects in the field, the invention provides a method for catalytic degradation of nitrogen/sulfur-containing VOCs by absorption and liquid phase, which realizes the control of the emission of nitrogen and sulfur-containing VOCs, has low cost and is particularly suitable for treating large air volume and low-concentration nitrogen and sulfur-containing VOCs (such as trimethylamine, methyl mercaptan and the like) generated in urban public construction and industrial processes.
A method for degrading nitrogen/sulfur-containing VOCs by absorption and liquid phase catalysis is characterized in that waste gas containing nitrogen/sulfur-containing VOCs passes through an absorption liquid containing an HZSM-5 molecular sieve under ultraviolet light to complete degradation of nitrogen/sulfur-containing VOCs;
the silicon-aluminum molar ratio of the HZSM-5 molecular sieve is 18-360: 1;
the pH value of the absorption liquid is 3-8;
the concentration of the HZSM-5 molecular sieve in the absorption liquid is 0.1-5 g/L.
In the present invention, "nitrogen/sulfur-containing VOCs" means nitrogen-containing VOCs and/or sulfur-containing VOCs unless otherwise specified.
The method transfers sulfur/nitrogen-containing VOCs with certain solubility in a gas phase into a liquid phase by adopting an absorption liquid absorption mode with specific pH, and applies the AOPs method to the treatment of the VOCs by combining with a specific addition amount and an HZSM-5 molecular sieve with a specific silicon-aluminum molar ratio. The HZSM-5 molecular sieve is a porous material, has a unique three-dimensional pore channel structure and a large specific surface area, and the invention takes the HZSM-5 molecular sieve with a specific silica-alumina molar ratio as an adsorbent to enhance the mass transfer of organic pollutants in a gas phase to a liquid phase. Meanwhile, the molecular sieve can enrich oxidative free radicals and O in the process of AOPs3And the pollutants are more effectively oxidized and degraded on the surface of the molecular sieve.
The invention essentially relates to a method for absorption-liquid phase catalytic degradation, wherein the surface of an HZSM-5 molecular sieve with a specific silicon-aluminum molar ratio in absorption liquid can be enriched with nitrogen/sulfur-containing VOCs and free radicals and ozone generated under the action of ultraviolet light, so that the mass transfer driving force of the substances is increased, and a reaction interface is provided. However, the HZSM-5 molecular sieve in the absorption liquid cannot be excessive, which may otherwise cause a decrease in the transmittance of ultraviolet light, and further cause a decrease in the degradation effect of the nitrogen/sulfur-containing VOCs. The Si/Al molar ratio of the molecular sieve also has great influence on the absorption and degradation efficiency, and the HZSM-5 molecular sieve with the specific Si/Al molar ratio is beneficial to the absorption of VOCs and ozone. In addition, the pH of the absorption liquid can affect the amount of ozone and free radicals generated by the ultraviolet light and the oxidation effect thereof, and the pH of the absorption liquid in the invention can be adjusted by using acid and alkali (such as sulfuric acid, sodium hydroxide and the like) commonly used in the field.
Preferably, the wavelength of the ultraviolet light is 185-254 nm.
Further preferably, the ultraviolet light is a combined light having a wavelength of 185nm and 254nm, and a ratio of an intensity of light having a wavelength of 185nm to an intensity of light having a wavelength of 254nm is 1: 9.
Preferably, the molar ratio of silicon to aluminum of the HZSM-5 molecular sieve is 130-360: 1.
Preferably, the pH of the absorption liquid is 5 to 6.
The method has extremely high degradation efficiency, and the retention time of the waste gas containing the nitrogen/sulfur-containing VOCs in the absorption liquid is 0.1-10 s. In a preferred embodiment, the residence time of the waste gas containing nitrogen/sulfur-containing VOCs in the absorption liquid is 5 s.
In a preferred embodiment, the concentration of the HZSM-5 molecular sieve in the absorption liquid is 0.2g/L, and the silica-alumina molar ratio of the HZSM-5 molecular sieve is 360: 1.
The invention also provides a system for degrading nitrogen/sulfur-containing VOCs by absorption and liquid phase catalysis, which comprises a liquid phase absorption-catalysis device filled with the absorption liquid;
an air inlet pipe with one closed end and the other end for nitrogen/sulfur-containing VOCs waste gas to enter is arranged in the liquid phase absorption-catalysis device and close to the bottom, a plurality of aeration pipes with one closed end are arranged on two sides of the air inlet pipe at intervals, and aeration holes are formed in the bottoms of the aeration pipes;
an ultraviolet lamp is arranged above the air inlet pipe in the liquid phase absorption-catalysis device.
Ultraviolet light with wavelengths of 185nm and 254nm may be generated using a vacuum ultraviolet lamp. In a preferred embodiment, the power of the ultraviolet lamp is 10-50W, and more preferably 30W.
Preferably, the bottom of the aeration pipe is provided with 3 rows of aeration holes along the axial direction, wherein the middle row of aeration holes is positioned at the bottom end of the aeration pipe.
Preferably, the system also comprises a gas collecting hood, a dust remover and a chimney;
the top of the liquid phase absorption-catalysis device is provided with an air outlet externally connected with the chimney;
the gas collecting hood, the dust remover and the gas inlet pipe are sequentially connected through a flue.
The method and the system for degrading the nitrogen/sulfur-containing VOCs by the absorption and liquid phase catalysis provided by the invention utilize the ultraviolet light to irradiate O generated by water and oxygen3And OH and other high-activity substances and the HZSM-5 molecular sieve with a specific silicon-aluminum molar ratio are subjected to liquid-phase catalytic oxidation reaction under the adsorption and catalysis synergistic effect, and finally, target pollutants containing nitrogen/sulfur VOCs are degraded into CO2、H2O and sulfate and nitrate which are easy to dissolve in water, and is particularly suitable for treating the waste gas containing nitrogen/sulfur-containing VOCs with large air volume and low concentration.
In a preferred embodiment, the air volume of the waste gas containing nitrogen/sulfur-containing VOCs is 2000-10000 m3The concentration of the nitrogen/sulfur-containing VOCs is 1-20 ppm.
The invention also provides application of the system in absorption-liquid phase catalytic degradation of nitrogen/sulfur-containing VOCs.
Compared with the prior art, the invention has the main advantages that:
(1) the invention has simple process and no secondary pollution. The invention utilizes the strong adsorption effect of the HZSM-5 molecular sieve with specific silica-alumina molar ratio to greatly enhance the solubility of target pollutants containing nitrogen/sulfur-containing VOCs in a liquid phase, and the 185nm vacuum ultraviolet light irradiates O2Produced O3And OH and other free radicals generated by photolysis of water can also be enriched on the molecular sieve, so that the oxidative degradation effect of the molecular sieve on nitrogen/sulfur-containing VOCs (volatile organic compounds) such as trimethylamine, methyl mercaptan and the like with large air volume and low concentration can be effectively enhanced, the removal efficiency can almost reach 100 percent, and NO is not detected in tail gasxAnd SO2And the like secondary contaminants. The by-products generated in the reaction process can be absorbed in the reaction liquid, and the secondary pollution is avoided through further advanced treatment by continuous ultraviolet irradiation.
(2) The invention has small occupied space and low operation cost, the HZSM-5 molecular sieve can be recycled, no additive such as additional active component or oxidant is needed, and O generated in the reaction process3Because the molecular sieve can be completely dissolved in water or enriched on the surface of the molecular sieve under the enrichment action, the molecular sieve can fully react with VOCs containing nitrogen/sulfur, and O in tail gas3The concentration is below the detection limit.
(3) The invention has better stability, and can stably and efficiently remove trimethylamine and methyl mercaptan for a long time.
Drawings
FIG. 1 is a schematic diagram of the configuration of an exemplary system for absorption-synergistic liquid-phase catalytic degradation of nitrogen/sulfur-containing VOCs;
FIG. 2 is a schematic front view of a liquid-phase absorption-catalytic apparatus of an embodiment;
FIG. 3 is a schematic left-side view of the liquid-phase absorption-catalytic apparatus of the embodiment;
FIG. 4 is a schematic view of the structure of an aeration tube in the liquid-phase absorption-catalyst apparatus according to the embodiment;
in the figure: the device comprises a gas collecting hood 1, a flue 2, a dust remover 3, a liquid phase absorption-catalysis device 4, a chimney 5, an ultraviolet lamp 6, an air inlet pipe 7, an aeration pipe 8, an air outlet 9 and an aeration hole 10.
Detailed Description
The invention is further described with reference to the following drawings and specific examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. The following examples are conducted under conditions not specified, usually according to conventional conditions, or according to conditions recommended by the manufacturer.
The structure of the system for catalytic degradation of nitrogen/sulfur-containing VOCs by absorption in coordination with liquid phase in the embodiment is shown in fig. 1, and comprises a gas collecting hood 1, a dust remover 3, a liquid phase absorption-catalysis device 4 and a chimney 5 which are sequentially connected through a flue 2.
As shown in fig. 2 and 3, the top of the liquid phase absorption-catalysis device 4 is provided with an air outlet 9 externally connected with a chimney 5. A horizontal air inlet pipe 7 with one end closed and the other end for nitrogen/sulfur-containing VOCs waste gas to enter is arranged in the liquid phase absorption-catalysis device 4 and close to the bottom, and the air inlet pipe 7 is connected with the dust remover 3 through a flue 2. Two sides of the air inlet pipe 7 are respectively provided with 10 horizontal aeration pipes 8 with one closed end at intervals. Two rows of 10 ultraviolet lamps 6 are uniformly arranged in the liquid phase absorption-catalysis device 4 at different heights above the air inlet pipe 7.
As shown in fig. 4, 3 rows of aeration holes 10 are axially arranged at the bottom of the aeration pipe 8, wherein the middle row of aeration holes 10 is located at the bottom end of the aeration pipe 8, and two rows at two sides are symmetrically arranged.
The liquid phase absorption-catalysis device 4 is filled with absorption liquid, and HZSM-5 molecular sieve is added into the absorption liquid, and the absorption liquid is fully stirred to be uniformly dispersed. The mole ratio of silicon to aluminum of the molecular sieve is 360:1, the specific surface area is 412.6m2G, average pore diameter 2.22 nm.
The following examples all used the above system and, unless otherwise specified, the reaction temperature was 25 ℃. The concentration of trimethylamine, methyl mercaptan and carbon dioxide was measured by gas chromatography. O is3By the use of O3The analyzer takes the measurements. NOx、SO2And measuring by adopting a multi-component smoke analyzer.
Application example 1
The ultraviolet light is a combined light of wavelengths of 185nm and 254nm, and the ratio of the light intensity of 185nm to 254nm is 1: 9.
Simulated exhaust gas volume 2000m3The residence time in the absorption liquid was 3 s. 36g of HZSM-5 molecular sieve with the molar ratio of silicon to aluminum being 360:1 is weighed and uniformly mixed with 180L of deionized water, and the mixture is continuously stirred for 8 hours at room temperature to obtain reaction liquid (absorption liquid). The simulated waste gas enters the liquid phase absorption-catalysis device through the bottom aeration pipe, and the initial concentration of the simulated waste gas is as follows: [ trimethylamine ]]10ppm, the carrier gas is air and the pressure is 1 atmosphere. When the pH of HZSM-5 molecular sieve slurry is 5, the removal rate of trimethylamine is 99.6 percent, and O in tail gas is3、NOxThe concentrations are all lower than the detection limit.
Application example 2
The ultraviolet light is a combined light of wavelengths of 185nm and 254nm, and the ratio of the light intensity of 185nm to 254nm is 1: 9.
Simulated exhaust gas volume 2000m3The residence time in the absorption liquid was 3 s. Weighing 36g of HZSM-5 molecular sieve with the molar ratio of silicon to aluminum being 360:1, uniformly mixing with 180L of deionized water, and continuously stirring for 8 hours at room temperature to obtain a reaction solution. The simulated waste gas enters the liquid phase absorption-catalysis device through the bottom aeration pipe, and the initial concentration of the simulated waste gas is as follows: [ Methylthiol ]]10ppm, the carrier gas is air and the pressure is 1 atmosphere. When the pH of the HZSM-5 molecular sieve slurry is 5, the removal rate of the methyl mercaptan is 99.5 percent, and the O in the tail gas is3、SO2The concentrations are all lower than the detection limit.
Application example 3
The ultraviolet light is a combined light of wavelengths of 185nm and 254nm, and the ratio of the light intensity of 185nm to 254nm is 1: 9.
Simulated exhaust gas volume 2000m3The residence time in the absorption liquid was 3 s. Weighing 36g of HZSM-5 molecular sieve with the molar ratio of silicon to aluminum being 360:1, uniformly mixing with 180L of deionized water, and continuously stirring for 8 hours at room temperature to obtain a reaction solution. Simulating bottom-to-bottom aeration of exhaust gasesThe gas pipe enters a liquid phase absorption-catalysis device, and the simulated initial concentration of the waste gas is as follows: [ trimethylamine ]]5ppm, [ methyl mercaptan]5ppm, the carrier gas is air and the pressure is 1 atmosphere. When the pH of HZSM-5 molecular sieve slurry is 5, the removal rate of trimethylamine is 99.3%, the removal rate of methyl mercaptan is 99.2%, and O in tail gas is3、NOx、SO2The concentrations are all lower than the detection limit.
Application example 4
The ultraviolet light is a combined light of wavelengths of 185nm and 254nm, and the ratio of the light intensity of 185nm to 254nm is 1: 9.
Simulated exhaust gas quantity 6000m3The residence time in the absorption liquid was 3 s. Weighing 36g of HZSM-5 molecular sieve with the molar ratio of silicon to aluminum being 360:1, uniformly mixing with 180L of deionized water, and continuously stirring for 8 hours at room temperature to obtain a reaction solution. The simulated waste gas enters the liquid phase absorption-catalysis device through the bottom aeration pipe, and the initial concentration of the simulated waste gas is as follows: [ trimethylamine ]]5ppm, [ methyl mercaptan]5ppm, the carrier gas is air and the pressure is 1 atmosphere. When the pH of HZSM-5 molecular sieve slurry is 6, the removal rate of trimethylamine is 96.2 percent, the removal rate of methyl mercaptan is 95.5 percent, and O in tail gas is3、NOx、SO2The concentrations are all lower than the detection limit.
Application example 5
The ultraviolet light is a combined light of wavelengths of 185nm and 254nm, and the ratio of the light intensity of 185nm to 254nm is 1: 9.
Simulated exhaust gas volume 2000m3The residence time in the absorption liquid was 3 s. Weighing 90g of HZSM-5 molecular sieve with the molar ratio of silicon to aluminum being 360:1, uniformly mixing the HZSM-5 molecular sieve with 180L of deionized water, and continuously stirring the mixture for 8 hours at room temperature to obtain reaction liquid. The simulated waste gas enters the liquid phase absorption-catalysis device through the bottom aeration pipe, and the initial concentration of the simulated waste gas is as follows: [ trimethylamine ]]5ppm, [ methyl mercaptan]5ppm, the carrier gas is air and the pressure is 1 atmosphere. When the pH of HZSM-5 molecular sieve slurry is 6, the removal rate of trimethylamine is 82.7%, the removal rate of methyl mercaptan is 80.5%, and O in tail gas is3、NOx、SO2The concentrations are all lower than the detection limit.
The comparison of application examples 4 and 5 shows that the HZSM-5 molecular sieve in the absorption liquid has too high concentration, and the removal rate of trimethylamine and methyl mercaptan is reduced due to the blocking of ultraviolet light.
Application example 6
The ultraviolet light is a combined light of wavelengths of 185nm and 254nm, and the ratio of the light intensity of 185nm to 254nm is 1: 9.
Simulated exhaust gas volume 2000m3H is used as the reference value. Weighing 36g of HZSM-5 molecular sieve with the molar ratio of silicon to aluminum being 360:1, uniformly mixing with 180L of deionized water, and continuously stirring for 8 hours at room temperature to obtain a reaction solution. The simulated waste gas enters the liquid phase absorption-catalysis device through the bottom aeration pipe, and the initial concentration of the simulated waste gas is as follows: [ trimethylamine ]]5ppm, [ methyl mercaptan]5ppm, the carrier gas is air and the pressure is 1 atmosphere. When the pH of HZSM-5 molecular sieve slurry is 4, the removal rate of trimethylamine is 99.5 percent, the removal rate of methyl mercaptan is 98.7 percent, and O in tail gas is3、NOx、SO2The concentrations are all lower than the detection limit.
Furthermore, it should be understood that various changes and modifications can be made by one skilled in the art after reading the above description of the present invention, and equivalents also fall within the scope of the invention as defined by the appended claims.

Claims (10)

1. A method for degrading nitrogen/sulfur-containing VOCs by absorption-liquid phase catalysis is characterized in that waste gas containing nitrogen/sulfur-containing VOCs passes through an absorption liquid containing an HZSM-5 molecular sieve under ultraviolet light to complete degradation of the nitrogen/sulfur-containing VOCs;
the silicon-aluminum molar ratio of the HZSM-5 molecular sieve is 18-360: 1;
the pH value of the absorption liquid is 3-8;
the concentration of the HZSM-5 molecular sieve in the absorption liquid is 0.1-5 g/L.
2. The method of claim 1, wherein the ultraviolet light has a wavelength of 185 to 254 nm.
3. The method of claim 2, wherein the ultraviolet light is a combination of light having wavelengths of 185nm and 254nm, and the ratio of the intensity of light having a wavelength of 185nm to the intensity of light having a wavelength of 254nm is 1: 9.
4. The method according to claim 1, wherein the pH of the absorption liquid is 5 to 6.
5. The method of claim 1, wherein the HZSM-5 molecular sieve has a specific surface area of 171.5 to 412.6m2/g。
6. The method according to claim 1, wherein the residence time of the waste gas containing nitrogen/sulfur-containing VOCs in the absorption liquid is 3 to 10 s.
7. A system for the absorption-concerted liquid-phase catalytic degradation of nitrogen/sulfur-containing VOCs comprising a liquid-phase absorption-catalytic unit containing the absorption liquid of claim 1;
an air inlet pipe with one closed end and the other end for nitrogen/sulfur-containing VOCs waste gas to enter is arranged in the liquid phase absorption-catalysis device and close to the bottom, a plurality of aeration pipes with one closed end are arranged on two sides of the air inlet pipe at intervals, and aeration holes are formed in the bottoms of the aeration pipes;
an ultraviolet lamp is arranged above the air inlet pipe in the liquid phase absorption-catalysis device.
8. The system of claim 7, wherein the bottom of the aeration pipe is provided with 3 rows of aeration holes along the axial direction, wherein the middle row of aeration holes is positioned at the bottom end of the aeration pipe.
9. The system of claim 7 or 8, further comprising a gas hood, a dust separator, and a chimney;
the top of the liquid phase absorption-catalysis device is provided with an air outlet externally connected with the chimney;
the gas collecting hood, the dust remover and the gas inlet pipe are sequentially connected through a flue.
10. According to the claimsThe use of the system of any one of claims 7 to 9 in absorption-synergistic liquid-phase catalytic degradation of nitrogen/sulfur-containing VOCs, wherein the air volume of the waste gas containing nitrogen/sulfur-containing VOCs is 2000-10000 m3The concentration of the nitrogen/sulfur-containing VOCs is 1-20 ppm.
CN202011138689.6A 2020-10-22 2020-10-22 Method and system for catalytic degradation of nitrogen/sulfur-containing VOCs (volatile organic compounds) by absorption and liquid phase Pending CN112426878A (en)

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