A method and system for treating low-concentration VOCs waste gas containing dust.

Abstract

This invention relates to the field of volatile organic compound (VOC) treatment, and discloses a method and system for treating low-concentration VOCs waste gas containing dust. The method includes the following steps: (1) mixing the waste gas to be treated, ozone, and a peroxide solution to obtain a mixture; (2) conveying the mixture to a circulating tower and treating it under ultraviolet irradiation to obtain a waste liquid and a gas phase; dehydrating the gas phase to obtain a gaseous material; and (3) subjecting the gaseous material obtained in step (2) to a catalytic oxidation reaction and an ozone decomposition reaction in sequence. The method described in this invention achieves efficient treatment of low-concentration VOCs waste gas containing dust, and the treated gas meets emission standards.

Description

Technical Field

[0001] This invention relates to the field of volatile organic compound (VOC) treatment, specifically to a method and system for treating dust-laden, low-concentration VOC waste gas. Background Technology

[0002] With economic and social development, people enjoy the conveniences brought about by rapid industrial development, while simultaneously paying increasing attention to environmental pollution control, mainly including water pollution, air pollution, and soil pollution. In recent years, air pollution has received widespread attention, with volatile organic compound (VOC) emissions being one of the causes.

[0003] VOCs treatment technologies have been developing for decades, generally falling into two categories: recovery and destruction. Common recovery methods include condensation, absorption, adsorption, and membrane separation. Recovery methods are often used to recover high-concentration, high-value-added materials, while destruction technologies are typically used for low-concentration, low-value-added materials. In industry, regenerative thermal oxidizers (RTO) and catalytic combustion (RCO) are commonly used. However, for low-concentration (<100ppm) industrial waste gases, RTO and RCO are not economical, not only due to high energy consumption during operation and maintenance, but also because some require additional fuel. Some industrial VOCs waste gases contain solid particles, such as silo exhaust. If recovery methods, such as adsorption or membrane methods, are used, these solid particles can clog the pores of the adsorbent material or membrane channels, thus reducing the device's VOCs treatment capacity. If destruction methods, such as conventional RCO, are used, solid particles can deposit on the catalyst surface, causing catalyst deactivation. Furthermore, due to the low VOCs concentration, RTO requires additional fuel, resulting in high operation and maintenance costs.

[0004] In summary, low-concentration VOCs with dust content pose a significant challenge in the field of VOCs treatment. The main difficulties lie in two aspects: firstly, the presence of solid particles in the gas phase means that commonly used industrial VOCs treatment methods, such as adsorption recovery and catalytic oxidation, can lead to problems like clogging and failure of adsorption materials and catalyst deactivation; secondly, the low concentration of VOCs means that conventional methods are energy-intensive and have high operation and maintenance costs. Therefore, it is necessary to seek new VOCs treatment technologies. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems of high difficulty in treating low-concentration VOCs waste gas containing dust, high energy consumption, and high operation and maintenance costs in the existing technology, and to provide a method and system for treating low-concentration VOCs waste gas containing dust.

[0006] To achieve the above objectives, the present invention provides a method for treating low-concentration VOCs waste gas containing dust, the method comprising the following steps:

[0007] (1) Mix the waste gas to be treated, ozone and peroxide solution to obtain a mixture;

[0008] (2) The mixture is fed into a circulating tower and treated under ultraviolet light to obtain waste liquid and gas phase. The gas phase is dehydrated to obtain gaseous material.

[0009] (3) The gaseous material obtained in step (2) is subjected to catalytic oxidation and ozone decomposition reaction in sequence.

[0010] Preferably, in step (1), the weight ratio of VOCs to ozone in the waste gas to be treated is 1:5-20.

[0011] Preferably, in step (1), the concentration of peroxide in the peroxide solution is 1×10⁻⁶. -3 -10×10 -3 mol / L.

[0012] Preferably, the peroxide is selected from one or more of hydrogen peroxide, sodium persulfate, and potassium persulfate.

[0013] Preferably, the wavelength of the ultraviolet light is 180-328nm.

[0014] Preferably, the temperature during the dehydration process is 1-5°C.

[0015] Preferably, the catalytic oxidation reaction is carried out in the presence of a catalyst;

[0016] Preferably, the catalyst is a Co-Mn bimetallic catalyst.

[0017] Preferably, the ozone decomposition reaction is carried out in the presence of a catalyst;

[0018] Preferably, the catalyst is manganese dioxide.

[0019] Preferably, the temperature of the catalytic oxidation reaction is 70-120℃.

[0020] Preferably, the temperature for the ozone decomposition reaction is 70-120℃.

[0021] Preferably, the method further includes: performing solid-liquid separation on the waste liquid.

[0022] Preferably, the concentration of VOCs in the waste gas to be treated is 10-200 mg / m³. 3 The dust concentration is 10-100 mg / m³ 3 .

[0023] A second aspect of the present invention provides a system for treating low-concentration VOCs waste gas containing dust, the system comprising: a gas-liquid mixer, a circulating tower, a coalescer, a reactor, a solid-liquid separator, an ozone generator, and a storage tank; the circulating tower is equipped with an ultraviolet lamp;

[0024] The peroxide solution from the storage tank, the ozone from the ozone generator, and the waste gas to be treated are mixed in the gas-liquid mixer to obtain a mixture;

[0025] The mixture from the gas-liquid mixer is processed in the circulating tower to obtain a gas phase and waste liquid;

[0026] The gas phase from the circulating tower is dehydrated in the coalescer to obtain a gaseous material;

[0027] The gaseous material from the coalescer is subjected to catalytic oxidation and ozone decomposition reactions in the reactor in sequence.

[0028] The waste liquid from the circulating tower undergoes solid-liquid separation in the solid-liquid separator.

[0029] Preferably, the liquid outlet of the solid-liquid separator is connected to the liquid storage tank.

[0030] Preferably, the power of the ultraviolet lamp is 10-30kW.

[0031] Preferably, a first centrifugal pump is provided between the circulating tower and the solid-liquid separator.

[0032] Preferably, a second centrifugal pump is provided between the liquid storage tank and the gas-liquid mixer.

[0033] A third aspect of the present invention provides the application of the method or system described above in the treatment of VOCs waste gas.

[0034] In this invention, the waste gas to be treated undergoes dust removal in a circulating tower, while simultaneously undergoing preliminary photo-oxidation degradation of VOCs under ultraviolet irradiation, followed by deep degradation through catalytic oxidation. The method described in this invention achieves highly efficient treatment of low-concentration VOCs-laden waste gas containing dust, and the treated gas meets emission standards. Furthermore, the method described in this invention achieves a removal efficiency of over 99.9% for solid particles smaller than 1 μm and a VOCs degradation efficiency of over 99%. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the system for treating low-concentration VOCs waste gas containing dust, as described in this invention.

[0036] Explanation of reference numerals in the attached figures

[0037] 1. Gas-liquid mixer 2. Circulation tower

[0038] 3 Second centrifugal pump 4 Coalescer

[0039] 5 Reactor 6 Solid-Liquid Separator

[0040] 7. Ozone generator 8. Storage tank

[0041] 9 First centrifugal pump Detailed Implementation

[0042] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0043] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0044] The first aspect of this invention provides a method for treating low-concentration VOCs waste gas containing dust, the method comprising the following steps:

[0045] (1) Mix the waste gas to be treated, ozone and peroxide solution to obtain a mixture;

[0046] (2) The mixture is fed into a circulating tower and treated under ultraviolet light to obtain waste liquid and gas phase. The gas phase is dehydrated to obtain gaseous material.

[0047] (3) The gaseous material obtained in step (2) is subjected to catalytic oxidation and ozone decomposition reaction in sequence.

[0048] In the method described in this invention, the waste gas to be treated, ozone, and peroxide solution are mixed to obtain a mixture. The presence of ozone and peroxide enables the VOCs in the mixture to undergo preliminary photo-oxidation degradation under subsequent ultraviolet light irradiation, which can further improve the degradation efficiency.

[0049] In order to further improve the treatment efficiency of dust-containing low-concentration VOCs waste gas, in the preferred embodiment, in step (1), the volume ratio of the waste gas to be treated to the peroxide solution is 10-30:1.

[0050] In a specific implementation, in step (1), the volume ratio of the waste gas to be treated to the peroxide solution can be 10:1, 15:1, 20:1, 25:1 or 30:1.

[0051] More preferably, the concentration of peroxide in the peroxide solution is / 1×10 -3 -10×10 -3 mol / L; specifically, it can be 1×10 -3 mol / L, 2×10 -3 mol / L, 3×10 -3 mol / L, 4×10 -3 mol / L, 5×10 -3 mol / L, 6×10 - 3 mol / L, 7×10 -3 mol / L, 8×10 -3 mol / L, 9×10 -3 mol / L or 10×10 -3 mol / L.

[0052] In a preferred embodiment, the peroxide is selected from one or more of hydrogen peroxide, sodium persulfate, and potassium persulfate.

[0053] In order to further improve the treatment efficiency of dust-containing low-concentration VOCs waste gas, in a preferred embodiment, in step (1), the weight ratio of VOCs to ozone in the waste gas to be treated is 1:5-20.

[0054] In the method described in this invention, the ozone can be provided by an ozone-containing mixture generated by an ozone generator.

[0055] In a specific embodiment, the solvent used in the peroxide aqueous solution is water.

[0056] To further improve the processing efficiency of the photo-oxidative degradation stage, in a preferred embodiment, the wavelength of the ultraviolet light is 180-328 nm. It is understood that the present invention does not limit the specific wavelength of the ultraviolet light, as long as it is between 180-328 nm.

[0057] In this invention, to further improve the catalytic oxidation degradation efficiency of the gas phase separated from the circulating tower, the gas phase can be dehydrated. In a preferred embodiment, the temperature during the dehydration treatment is 1-5°C.

[0058] In a preferred embodiment, the catalytic oxidation reaction is carried out in the presence of a catalyst.

[0059] More preferably, the catalyst is a Co-Mn bimetallic catalyst.

[0060] In a preferred embodiment, the ozone decomposition reaction is carried out in the presence of a catalyst.

[0061] More preferably, the catalyst is manganese dioxide.

[0062] In a preferred embodiment, the temperature of the catalytic oxidation reaction is 80-120°C.

[0063] In a preferred embodiment, the temperature for the ozone decomposition reaction is 80-120°C.

[0064] In a preferred embodiment, the method further includes: performing solid-liquid separation on the waste liquid. The liquid phase obtained after solid-liquid separation can be returned to step (1) for reuse, reducing resource waste.

[0065] In a preferred embodiment, the concentration of VOCs in the waste gas to be treated is 10-200 mg / m³. 3 The dust concentration is 10-100 mg / m³ 3 .

[0066] It should be noted that in this invention, the concentration of VOCs refers to the concentration of non-methane total hydrocarbons, and the weight of VOCs refers to the weight of non-methane total hydrocarbons.

[0067] According to one embodiment of the present invention, a method for treating dust-laden, low-concentration VOCs waste gas includes the following steps:

[0068] (1) Mix the waste gas to be treated, ozone and peroxide solution to obtain a mixture;

[0069] (2) The mixture is fed into a circulating tower and treated under ultraviolet light to obtain a gas phase and waste liquid. The gas phase is then dehydrated to obtain a gaseous material.

[0070] (3) The gaseous material obtained in step (2) is subjected to catalytic oxidation and ozone decomposition reaction in sequence;

[0071] (4) The waste liquid separated from the circulating tower is subjected to solid-liquid separation, and the resulting liquid phase is returned to step (1) for reuse.

[0072] The method described in this invention involves mixing the waste gas to be treated, an ozone solution, and a peroxide solution to obtain a mixture. This mixture is then fed into a circulating tower for treatment. In the circulating tower, the liquid and gas phases can fully contact each other. Solid particles in the gas phase are effectively removed and enter the waste liquid. Simultaneously, under ultraviolet irradiation, ozone and peroxide generate reactive oxygen atoms (hydroxyl radicals) to initially degrade VOCs in the gas phase. The gas phase obtained after circulating tower treatment passes through a catalytic oxidation bed to degrade residual VOCs, and then passes through an ozone degradation bed to remove unreacted ozone, thus obtaining gas that meets emission standards. The waste liquid obtained after circulating tower treatment undergoes solid-liquid separation, and the resulting liquid phase can be reused, achieving zero wastewater discharge. Therefore, the method described in this invention can effectively remove solid particles and VOCs from dust-laden, low-concentration VOCs waste gas.

[0073] A second aspect of the present invention provides a system for treating low-concentration VOCs waste gas containing dust, the system being used to implement the methods described above, in conjunction with reference to [the relevant literature]. Figure 1 The system includes: a gas-liquid mixer 1, a circulation tower 2, a coalescer 4, a reactor 5, a solid-liquid separator 6, an ozone generator 7, and a storage tank 8; the circulation tower 2 is equipped with an ultraviolet lamp (not shown in the figure);

[0074] The peroxide solution from the storage tank 8, the ozone from the ozone generator 7, and the waste gas to be treated are mixed in the gas-liquid mixer 1 to obtain a mixture.

[0075] The mixture from the gas-liquid mixer is processed in the circulating tower 2 to obtain a gas phase and waste liquid;

[0076] The gas phase from the circulating tower 2 is dehydrated in the coalescer 4 to obtain gaseous material;

[0077] The gaseous material from the coalescer 4 is subjected to catalytic oxidation and ozone decomposition reactions in the reactor 5 in sequence.

[0078] The waste liquid from the circulation tower 2 undergoes solid-liquid separation in the solid-liquid separator 6.

[0079] In a specific embodiment, the gas-liquid mixer 1 has an exhaust gas inlet, through which the exhaust gas to be treated is processed in the gas-liquid mixer 1.

[0080] In this invention, the ozone generator 7 shown is used to provide ozone.

[0081] In a specific embodiment, the ozone generator 7 has an ozone outlet, which is connected to the gas-liquid mixer 1.

[0082] In this invention, the storage tank 8 is used to store peroxide solution.

[0083] In a specific embodiment, the liquid storage tank 8 has a peroxide solution outlet, which is connected to the gas-liquid mixer 1.

[0084] The concentration of peroxide in the peroxide solution is 1×10⁻⁶. -3 -10×10 -3 mol / L. Specifically, it can be 1×10⁻⁶ mol / L. -3 mol / L, 2×10 -3 mol / L, 3×10 -3 mol / L, 4×10 -3 mol / L, 5×10 -3 mol / L, 6×10 -3 mol / L, 7×10 - 3 mol / L, 8×10 -3 mol / L, 9×10 -3 mol / L or 10×10 -3 mol / L.

[0085] In a preferred embodiment, the peroxide is selected from one or more of hydrogen peroxide, sodium persulfate, and potassium persulfate.

[0086] In the system described in this invention, the peroxide solution from the storage tank 8, the ozone from the ozone generator 7, and the waste gas to be treated are mixed in the gas-liquid mixer 1 to obtain a mixture, which is a gas-liquid two-phase mixture.

[0087] In the system described in this invention, the main structure of the circulating tower 2 is consistent with that of a conventional circulating tower, and the gas-liquid mixture enters the circulating tower from the side for treatment. By using ultraviolet lamps installed inside the circulating tower 2, the gas-liquid mixture undergoes dust removal while simultaneously pre-treating VOCs through photo-oxidative degradation. Because the gas and liquid phases can fully contact inside the circulating tower, the VOCs pre-treatment efficiency is high.

[0088] In a preferred embodiment, in order to improve the pretreatment efficiency in the circulation tower 2, the direction of the ultraviolet lamp is perpendicular to the fluid flow direction.

[0089] In a preferred embodiment, in order to improve the pretreatment efficiency in the circulation tower 2, the power of the ultraviolet lamp is 10-30kW.

[0090] In this invention, the ultraviolet lamp is used to provide ultraviolet light, and any ultraviolet lamp capable of providing ultraviolet light with a wavelength of 180-328nm can be used in the system described in this invention.

[0091] In a specific implementation, the circulating tower 2 is provided with a gas phase outlet and a waste liquid outlet. The gas phase outlet is connected to the coalescer, and the waste liquid outlet is connected to the solid-liquid separator.

[0092] In this invention, the coalescer 4 is used to dehydrate the gas phase separated in the circulating tower 2 to obtain gaseous material.

[0093] In a preferred embodiment, the coalescer 4 has a liquid outlet connected to the circulation tower 2. Water generated during the dehydration process in the coalescer 4 can be discharged through the liquid outlet and then returned to the circulation tower 2 for reuse.

[0094] In a specific embodiment, the coalescer 4 is filled with superhydrophilic material and superhydrophobic material. The contact angle between the superhydrophilic material and water is 0°, and the contact angle between the superhydrophobic material and water is greater than 150°, with a roll-off angle of less than 5°.

[0095] To further improve the dehydration effect in the coalescer, in a specific embodiment, the temperature is maintained at 1-5°C when using coalescer 4.

[0096] In this invention, the gaseous material from the coalescer 4 undergoes catalytic oxidation and ozone decomposition reactions sequentially in the reactor 5.

[0097] In a specific embodiment, the reactor 5 is sequentially filled with a catalytic oxidation catalyst and an ozone decomposition catalyst along the gas flow direction. This allows the gaseous material to undergo catalytic oxidation in the presence of the catalytic oxidation catalyst, followed by ozone decomposition in the presence of the ozone decomposition catalyst. The catalytic oxidation process degrades VOCs, and the ozone decomposition process removes unreacted ozone, ensuring that the gas discharged from the reactor meets emission standards.

[0098] In a specific implementation, the catalyst for the catalytic oxidation reaction is a Co-Mn bimetallic catalyst; the catalyst for the ozone decomposition reaction is manganese dioxide.

[0099] In a specific implementation, the temperature of the catalytic bed in reactor 5 is set to 80-120°C, that is, the temperature during the reaction in reactor 5 is 80-120°C.

[0100] In this invention, the solid-liquid separator 6 is used to perform solid-liquid separation on the waste liquid obtained in the circulating tower 2.

[0101] In a preferred embodiment, the liquid outlet of the solid-liquid separator 6 is connected to the storage tank 8. The waste liquid from the circulation tower 2 undergoes solid-liquid separation in the solid-liquid separator 6, and the resulting liquid phase can be transported to the storage tank 8 for reuse.

[0102] In a specific implementation, the solid-liquid separator 6 is a centrifugal solid-liquid separator with a solid removal efficiency of 95-99%.

[0103] In a specific embodiment, a first centrifugal pump 9 is provided between the circulating tower 2 and the solid-liquid separator 6. The first centrifugal pump 9 is used to transport the waste liquid separated from the circulating tower 2 to the solid-liquid separator 6 for solid-liquid separation.

[0104] In a specific embodiment, a second centrifugal pump 3 is provided between the liquid storage tank 8 and the gas-liquid mixer 1. The second centrifugal pump is used to transport the solution from the liquid storage tank 8 to the gas-liquid mixer 1.

[0105] The system described in this invention employs an improved circulating tower using ultraviolet lamps. Within this tower, not only is dust removal effective in the exhaust gas, but pre-removal of VOCs is also achieved. Ozone is mixed in the gas phase, and an oxidant is added to the liquid phase, enabling synergistic removal of VOCs from both the gas and liquid phases within the circulating tower. Residual VOCs are then removed via a catalytic oxidation bed, significantly improving the VOCs removal efficiency. Therefore, the system described in this invention is particularly suitable for treating exhaust gas containing low concentrations of dust-laden VOCs.

[0106] The third aspect of this invention provides the application of the method or system described above in the treatment of VOCs waste gas.

[0107] The method or system described in this invention is applicable to the treatment of low-concentration VOCs containing dust, such as silo exhaust gas and electronic component processing enterprises, and can also be extended to other low-concentration VOCs treatment sites.

[0108] The following examples further illustrate the method and system for treating low-concentration VOCs waste gas containing dust according to the present invention. These examples are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures; however, the scope of protection of the present invention is not limited to the following examples.

[0109] Adopting such Figure 1 The system shown for treating low-concentration VOCs waste gas containing dust is operated according to the following embodiment. The system includes: a gas-liquid mixer 1, a circulating tower 2, a coalescer 4, a reactor 5, a solid-liquid separator 6, an ozone generator 7, a storage tank 8, a first centrifugal pump 9, and a second centrifugal pump 3.

[0110] The circulating tower 2 is equipped with an ultraviolet lamp; the gas-liquid mixer 1 has a waste gas inlet; the circulating tower 2 has a gas phase outlet and a waste liquid outlet; the gas phase outlet is connected to the coalescer 4; the waste liquid outlet is connected to the solid-liquid separator 6; the liquid outlet of the solid-liquid separator 6 is connected to the storage tank 8; the first centrifugal pump 9 is disposed between the circulating tower 2 and the solid-liquid separator 6; the second centrifugal pump 3 is disposed between the storage tank 8 and the gas-liquid mixer 1.

[0111] The coalescer 4 is filled with superhydrophilic and superhydrophobic materials. The contact angle between the superhydrophilic material and water is 0°, and the contact angle between the superhydrophobic material and water is greater than 150°, with a roll-off angle of less than 5°.

[0112] In reactor 5, a catalytic oxidation reaction catalyst and an ozone decomposition reaction catalyst are sequentially packed along the gas flow direction. The catalytic oxidation reaction catalyst is a Co-Mn bimetallic catalyst, and the ozone decomposition reaction catalyst is manganese dioxide.

[0113] Example 1

[0114] The main component of the exhaust gas: dust concentration of 50 mg / m³ 3 The concentration of VOCs (toluene) was 20 mg / m³. 3 ;

[0115] The peroxide solution is an aqueous solution of potassium persulfate, and the concentration of potassium persulfate is 8 × 10⁻⁶. -3 mol / L;

[0116] (1) The waste gas, the ozone mixture from the ozone generator 7, and the peroxide solution from the storage tank 8 are mixed in the gas-liquid mixer 1 to obtain a mixture; wherein the waste gas flow rate is 200 m³ / h. 3 / h, the flow rate of the oxide solution is 20m³ / h. 3 / h, that is, the volume ratio of waste gas to peroxide solution is 10:1; the weight ratio of VOCs to ozone in the waste gas is controlled to be 1:10;

[0117] (2) Turn on the ultraviolet lamp (power is 25kW) and transport the mixture obtained in step (1) to the circulation tower 2 for treatment under ultraviolet light (wavelength is 185nm) to obtain gas phase and waste liquid.

[0118] (3) The gas phase separated from the circulation tower 2 in step (2) is transported to the coalescer 4 for dehydration treatment. The temperature during dehydration treatment is 3°C to obtain gaseous material.

[0119] (4) The gaseous material obtained in step (3) is transported to reactor 5 for catalytic oxidation and ozone decomposition reaction in sequence; the catalyst bed temperature in reactor 5 is 120℃;

[0120] (5) The waste liquid obtained in step (2) is transported to the solid-liquid separator 6 for solid-liquid separation, and the separated liquid phase is transported to the storage tank 8.

[0121] The gas at the outlet of reactor 5 was tested, and the dust concentration was less than or equal to 0.01 mg / m³. 3 The concentration of toluene is less than 0.05 mg / m³. 3 The ozone concentration was 0.

[0122] Example 2

[0123] The main component of the exhaust gas: dust concentration of 50 mg / m³ 3 The concentration of VOCs (toluene) was 20 mg / m³. 3 ;

[0124] The peroxide solution is an aqueous solution of hydrogen peroxide, and the concentration of hydrogen peroxide is 5 × 10⁻⁶. -3 mol / L;

[0125] (1) The waste gas, the ozone mixture from the ozone generator 7, and the peroxide solution from the storage tank 8 are mixed in the gas-liquid mixer 1 to obtain a mixture; wherein the waste gas flow rate is 200 m³ / h. 3 / h, the flow rate of the oxide solution is 8m³ / h. 3 / h, that is, the volume ratio of waste gas to peroxide solution is 25:1; the weight ratio of VOCs to ozone in the waste gas is controlled to be 1:8;

[0126] (2) Turn on the ultraviolet lamp (power is 15kW) and transport the mixture obtained in step (1) to the circulation tower 2 for treatment under ultraviolet light (wavelength is 185nm) to obtain gas phase and waste liquid.

[0127] (3) The gas phase separated from the circulation tower 2 in step (2) is transported to the coalescer 4 for dehydration treatment. The temperature during dehydration treatment is 1℃ to obtain gaseous material.

[0128] (4) The gaseous material obtained in step (3) is transported to reactor 5 for catalytic oxidation and ozone decomposition reaction in sequence; the catalyst bed temperature in reactor 5 is 100℃;

[0129] (5) The waste liquid obtained in step (2) is transported to the solid-liquid separator 6 for solid-liquid separation, and the separated liquid phase is transported to the storage tank 8.

[0130] The gas at the outlet of reactor 5 was tested, and the dust concentration was less than or equal to 4.6 mg / m³. 3 The concentration of toluene is less than 0.42 mg / m³. 3 The ozone concentration was 0.

[0131] Example 3

[0132] The main component of the exhaust gas: dust concentration of 100 mg / m³ 3 The concentration of VOCs (formaldehyde) is 100 mg / m³. 3 ;

[0133] The peroxide solution is an aqueous solution of sodium persulfate, and the concentration of sodium persulfate is 10 × 10⁻⁶. -3 mol / L;

[0134] (1) The waste gas, the ozone mixture from the ozone generator 7, and the peroxide solution from the storage tank 8 are mixed in the gas-liquid mixer 1 to obtain a mixture; wherein the waste gas flow rate is 150 m³ / h. 3 / h, the flow rate of the oxide solution is 8m³ / h. 3 / h, that is, the volume ratio of waste gas to peroxide solution is 18.75:1; the weight ratio of VOCs to ozone in the waste gas is controlled to be 1:16;

[0135] (2) Turn on the ultraviolet lamp (power is 10kW) and transport the mixture obtained in step (1) to the circulation tower 2 for treatment under ultraviolet light (wavelength is 185nm) to obtain gas phase and waste liquid.

[0136] (3) The gas phase separated from the circulation tower 2 in step (2) is transported to the coalescer 4 for dehydration treatment. The temperature during dehydration treatment is 3°C to obtain gaseous material.

[0137] (4) The gaseous material obtained in step (3) is transported to reactor 5 for catalytic oxidation and ozone decomposition reaction in sequence; the catalyst bed temperature in reactor 5 is 120℃;

[0138] (5) The waste liquid obtained in step (2) is transported to the solid-liquid separator 6 for solid-liquid separation, and the separated liquid phase is transported to the storage tank 8.

[0139] The gas at the outlet of reactor 5 was tested, and the dust concentration was less than or equal to 1.7 mg / m³. 3 The concentration of formaldehyde is 0, and the concentration of ozone is 0.

[0140] Example 4

[0141] The main component of the exhaust gas: dust concentration of 80 mg / m³ 3 The concentration of VOCs (formaldehyde) was 150 mg / m³. 3 ;

[0142] The peroxide solution is an aqueous solution of hydrogen peroxide, and the concentration of hydrogen peroxide is 4 × 10⁻⁶. -3 mol / L;

[0143] (1) The waste gas, the ozone mixture from the ozone generator 7, and the peroxide solution from the storage tank 8 are mixed in the gas-liquid mixer 1 to obtain a mixture; wherein the waste gas flow rate is 200 m³ / h. 3 / h, the flow rate of the oxide solution is 10m³ / h. 3 / h, that is, the volume ratio of waste gas to peroxide solution is 20:1; the weight ratio of VOCs to ozone in the waste gas is controlled to be 1:16;

[0144] (2) Turn on the ultraviolet lamp (power is 15kW) and transport the mixture obtained in step (1) to the circulation tower 2 for treatment under ultraviolet light (wavelength is 254nm) to obtain gas phase and waste liquid.

[0145] (3) The gas phase separated from the circulation tower 2 in step (2) is transported to the coalescer 4 for dehydration treatment. The temperature during dehydration treatment is 1℃ to obtain gaseous material.

[0146] (4) The gaseous material obtained in step (3) is transported to reactor 5 for catalytic oxidation and ozone decomposition reaction in sequence; the catalyst bed temperature in reactor 5 is 100℃;

[0147] (5) The waste liquid obtained in step (2) is transported to the solid-liquid separator 6 for solid-liquid separation, and the separated liquid phase is transported to the storage tank 8.

[0148] The gas at the outlet of reactor 5 was tested, and the dust concentration was less than or equal to 1.3 mg / m³. 3 The concentration of formaldehyde is 0, and the concentration of ozone is 0.

[0149] Example 5

[0150] The main component of the exhaust gas: dust concentration of 100 mg / m³ 3 The concentration of VOCs (benzene) is 10 mg / m³. 3 ;

[0151] The peroxide solution is an aqueous solution of potassium persulfate, and the concentration of potassium persulfate is 6 × 10⁻⁶. -3 mol / L;

[0152] (1) The waste gas, the ozone mixture from the ozone generator 7, and the peroxide solution from the storage tank 8 are mixed in the gas-liquid mixer 1 to obtain a mixture; wherein the waste gas flow rate is 100 m³ / h. 3 / h, the flow rate of the oxide solution is 5m³ / h. 3 / h, that is, the volume ratio of waste gas to peroxide solution is 20:1; the weight ratio of VOCs to ozone in the waste gas is controlled to be 1:10;

[0153] (2) Turn on the ultraviolet lamp (power is 20kW) and transport the mixture obtained in step (1) to the circulation tower 2 for treatment under ultraviolet light (wavelength is 185nm) to obtain gas phase and waste liquid.

[0154] (3) The gas phase separated in the circulation tower 2 in step (2) is transported to the coalescer 4 for dehydration treatment. The temperature during dehydration treatment is 5°C to obtain gaseous material.

[0155] (4) The gaseous material obtained in step (3) is transported to reactor 5 for catalytic oxidation and ozone decomposition reaction in sequence; the catalyst bed temperature in reactor 5 is 70℃;

[0156] (5) The waste liquid obtained in step (2) is transported to the solid-liquid separator 6 for solid-liquid separation, and the separated liquid phase is transported to the storage tank 8.

[0157] The gas at the outlet of reactor 5 was tested, and the dust concentration was less than or equal to 3.2 mg / m³. 3 The concentration of benzene is less than 1.7 mg / m³. 3 The ozone concentration was 0.03 mg / m³. 3 .

[0158] Example 6

[0159] The main component of the exhaust gas: dust concentration of 10 mg / m³ 3 The concentration of VOCs (toluene) was 20 mg / m³. 3 ;

[0160] The peroxide solution is an aqueous solution of potassium persulfate, and the concentration of potassium persulfate is 6 × 10⁻⁶. -3 mol / L;

[0161] (1) The waste gas, the ozone mixture from the ozone generator 7, and the peroxide solution from the storage tank 8 are mixed in the gas-liquid mixer 1 to obtain a mixture; wherein, the waste gas flow rate is 50 m³ / h. 3 / h, the flow rate of the oxide solution is 5m³ / h. 3 / h, that is, the volume ratio of waste gas to peroxide solution is 10:1; the weight ratio of VOCs to ozone in the waste gas is controlled to be 1:12;

[0162] (2) Turn on the ultraviolet lamp (power is 20kW) and transport the mixture obtained in step (1) to the circulation tower 2 for treatment under ultraviolet light (wavelength is 254nm) to obtain gas phase and waste liquid.

[0163] (3) The gas phase separated from the circulation tower 2 in step (2) is transported to the coalescer 4 for dehydration treatment. The temperature during dehydration treatment is 3°C to obtain gaseous material.

[0164] (4) The gaseous material obtained in step (3) is transported to reactor 5 for catalytic oxidation and ozone decomposition reaction in sequence; the catalyst bed temperature in reactor 5 is 90℃;

[0165] (5) The waste liquid obtained in step (2) is transported to the solid-liquid separator 6 for solid-liquid separation, and the separated liquid phase is transported to the storage tank 8.

[0166] The gas at the outlet of reactor 5 was tested, and the dust concentration was less than or equal to 0.01 mg / m³. 3 The concentration of toluene is less than 1.5 mg / m³. 3 The ozone concentration was 0.05 mg / m³. 3 .

[0167] Example 7

[0168] The main component of the exhaust gas: dust concentration of 50 mg / m³ 3 The concentration of VOCs (benzene) is 15 mg / m³. 3 ;

[0169] The peroxide solution is an aqueous solution of potassium persulfate, and the concentration of potassium persulfate is 10 × 10⁻⁶. -3 mol / L;

[0170] (1) The waste gas, the ozone mixture from the ozone generator 7, and the peroxide solution from the storage tank 8 are mixed in the gas-liquid mixer 1 to obtain a mixture; wherein the waste gas flow rate is 200 m³ / h. 3 / h, the flow rate of the oxide solution is 10m³ / h. 3 / h, that is, the volume ratio of waste gas to peroxide solution is 20:1, and the weight ratio of VOCs to ozone in waste gas is controlled to be 1:12;

[0171] (2) Turn on the ultraviolet lamp (power is 25kW) and transport the mixture obtained in step (1) to the circulation tower 2 for treatment under ultraviolet light (wavelength is 185nm) to obtain gas phase and waste liquid.

[0172] (3) The gas phase separated from the circulation tower 2 in step (2) is transported to the coalescer 4 for dehydration treatment. The temperature during dehydration treatment is 3°C to obtain gaseous material.

[0173] (4) The gaseous material obtained in step (3) is transported to reactor 5 for catalytic oxidation and ozone decomposition reaction in sequence; the catalyst bed temperature in reactor 5 is 100℃;

[0174] (5) The waste liquid obtained in step (2) is transported to the solid-liquid separator 6 for solid-liquid separation, and the separated liquid phase is transported to the storage tank 8.

[0175] The gas at the outlet of reactor 5 was tested, and the dust concentration was less than or equal to 1.3 mg / m³. 3 The concentration of benzene is less than 0.5 mg / m³. 3 The ozone concentration was 0.

[0176] Example 8

[0177] The main component of the exhaust gas: dust concentration of 50 mg / m³ 3 The concentration of VOCs (cyclohexane) was 30 mg / m³. 3 ;

[0178] The peroxide solution is an aqueous solution of hydrogen peroxide, and the concentration of hydrogen peroxide is 8 × 10⁻⁶. -3 mol / L;

[0179] (1) The waste gas, the ozone mixture from the ozone generator 7, and the peroxide solution from the storage tank 8 are mixed in the gas-liquid mixer 1 to obtain a mixture; wherein the waste gas flow rate is 200 m³ / h. 3 The flow rate of the oxide solution is 16 m³ / h. 3 / h, that is, the volume ratio of waste gas to peroxide solution is 12.5:1, and the weight ratio of VOCs to ozone in waste gas is controlled to be 1:9;

[0180] (2) Turn on the ultraviolet lamp (power is 25kW) and transport the mixture obtained in step (1) to the circulation tower 2 for treatment under ultraviolet light (wavelength is 185nm) to obtain gas phase and waste liquid.

[0181] (3) The gas phase separated from the circulation tower 2 in step (2) is transported to the coalescer 4 for dehydration treatment. The temperature during dehydration treatment is 3°C to obtain gaseous material.

[0182] (4) The gaseous material obtained in step (3) is transported to reactor 5 for catalytic oxidation and ozone decomposition reaction in sequence; the catalyst bed temperature in reactor 5 is 120℃;

[0183] (5) The waste liquid obtained in step (2) is transported to the solid-liquid separator 6 for solid-liquid separation, and the separated liquid phase is transported to the storage tank 8.

[0184] The gas at the outlet of reactor 5 was tested, and the dust concentration was less than or equal to 0.6 mg / m³. 3 The concentration of cyclohexane is less than 0.32 mg / m³. 3 The ozone concentration was 0.

[0185] Example 9

[0186] The main component of the exhaust gas: dust concentration of 50 mg / m³ 3The concentration of VOCs (toluene) was 20 mg / m³. 3 ;

[0187] The peroxide solution is an aqueous solution of potassium persulfate, and the concentration of potassium persulfate is 10 × 10⁻⁶. -3 mol / L;

[0188] (1) The waste gas, the ozone mixture from the ozone generator 7, and the peroxide solution from the storage tank 8 are mixed in the gas-liquid mixer 1 to obtain a mixture; wherein the waste gas flow rate is 150 m³ / h. 3 The flow rate of the oxide solution is 15 m³ / h. 3 / h, that is, the volume ratio of waste gas to peroxide solution is 10:1; the weight ratio of VOCs to ozone in the waste gas is controlled to be 1:7;

[0189] (2) Turn on the ultraviolet lamp (power is 25kW) and transport the mixture obtained in step (1) to the circulation tower 2 for treatment under ultraviolet light (wavelength is 185nm) to obtain gas phase and waste liquid.

[0190] (3) The gas phase separated from the circulation tower 2 in step (2) is transported to the coalescer 4 for dehydration treatment. The temperature during dehydration treatment is 3°C to obtain gaseous material.

[0191] (4) The gaseous material obtained in step (3) is transported to reactor 5 for catalytic oxidation and ozone decomposition reaction in sequence; the catalyst bed temperature in reactor 5 is 100℃;

[0192] (5) The waste liquid obtained in step (2) is transported to the solid-liquid separator 6 for solid-liquid separation, and the separated liquid phase is transported to the storage tank 8.

[0193] The gas at the outlet of reactor 5 was tested, and the dust concentration was less than or equal to 0.03 mg / m³. 3 The concentration of toluene is less than 0.15 mg / m³. 3 The ozone concentration was 0.

[0194] Example 10

[0195] The main component of the exhaust gas: dust concentration of 50 mg / m³ 3 The concentration of VOCs (toluene) was 20 mg / m³. 3 ;

[0196] The peroxide solution is an aqueous solution of sodium persulfate, and the concentration of sodium persulfate is 1×10⁻⁶. -3 mol / L;

[0197] (1) The waste gas, the ozone mixture from the ozone generator 7, and the peroxide solution from the storage tank 8 are mixed in the gas-liquid mixer 1 to obtain a mixture; wherein the waste gas flow rate is 200 m³ / h. 3 / h, the flow rate of the oxide solution is 10m³ / h. 3 / h, that is, the volume ratio of waste gas to peroxide solution is 20:1, and the weight ratio of VOCs to ozone in waste gas is controlled to be 1:7;

[0198] (2) Turn on the ultraviolet lamp (power is 30kW) and transport the mixture obtained in step (1) to the circulation tower 2 for treatment under ultraviolet light (wavelength is 185nm) to obtain gas phase and waste liquid.

[0199] (3) The gas phase separated from the circulation tower 2 in step (2) is transported to the coalescer 4 for dehydration treatment. The temperature during dehydration treatment is 3°C to obtain gaseous material.

[0200] (4) The gaseous material obtained in step (3) is transported to reactor 5 for catalytic oxidation and ozone decomposition reaction in sequence; the catalyst bed temperature in reactor 5 is 90℃;

[0201] (5) The waste liquid obtained in step (2) is transported to the solid-liquid separator 6 for solid-liquid separation, and the separated liquid phase is transported to the storage tank 8.

[0202] The gas at the outlet of reactor 5 was tested, and the dust concentration was less than or equal to 1.3 mg / m³. 3 The concentration of toluene is less than 0.5 mg / m³. 3 The ozone concentration was 0.01 mg / m³. 3 .

[0203] Comparative Example 1

[0204] The method described in Example 1 was implemented, except that the ultraviolet lamp was not turned on and the peroxide solution was replaced with water.

[0205] Specifically, the main component of the exhaust gas is dust, with a concentration of 50 mg / m³. 3 The concentration of VOCs (toluene) was 20 mg / m³. 3 ;

[0206] (1) The waste gas, the ozone mixture from the ozone generator 7, and the water from the storage tank 8 are mixed in the gas-liquid mixer 1 to obtain a mixture; wherein the waste gas flow rate is 200 m³ / h. 3 / h, water flow rate is 20m³ / h 3 / h, that is, the volume ratio of exhaust gas to water is 10:1, and the weight ratio of VOCs to ozone in the exhaust gas is controlled to be 1:10;

[0207] (2) The mixture obtained in step (1) is transported to the circulating tower 2 for processing to obtain gas phase and waste liquid;

[0208] (3) The gas phase separated from the circulation tower 2 in step (2) is transported to the coalescer 4 for dehydration treatment. The temperature during dehydration treatment is 3°C to obtain gaseous material.

[0209] (4) The gaseous material obtained in step (3) is transported to reactor 5 for catalytic oxidation and ozone decomposition reaction in sequence; the catalyst bed temperature in reactor 5 is 120℃;

[0210] (5) The waste liquid obtained in step (2) is transported to the solid-liquid separator 6 for solid-liquid separation, and the separated liquid phase is transported to the storage tank 8.

[0211] The gas at the outlet of reactor 5 was tested, and the dust concentration was less than or equal to 0.01 mg / m³. 3 The concentration of toluene is less than 12.8 mg / m³. 3 The ozone concentration was 0.

[0212] Comparative Example 2

[0213] The method described in Example 1 is implemented, except that ozone is not used.

[0214] Specifically, the main component of the exhaust gas is dust, with a concentration of 50 mg / m³. 3 The concentration of VOCs (toluene) was 20 mg / m³. 3 ;

[0215] The peroxide solution is an aqueous solution of potassium persulfate, and the concentration of potassium persulfate is 8 × 10⁻⁶. -3 mol / L;

[0216] (1) The waste gas and the peroxide solution from the storage tank 8 are mixed in the gas-liquid mixer 1 to obtain a mixture; wherein the waste gas flow rate is 200 m³ / h. 3 / h, the flow rate of the oxide solution is 10m³ / h. 3 / h, meaning the volume ratio of waste gas to peroxide solution is 10:1;

[0217] (2) Turn on the ultraviolet lamp (power is 25kW) and transport the mixture obtained in step (1) to the circulation tower 2 for treatment under ultraviolet light (wavelength is 185nm) to obtain gas phase and waste liquid.

[0218] (3) The gas phase separated from the circulation tower 2 in step (2) is transported to the coalescer 4 for dehydration treatment. The temperature during dehydration treatment is 3°C to obtain gaseous material.

[0219] (4) The gaseous material obtained in step (3) is transported to reactor 5 for catalytic oxidation reaction in sequence; the catalyst bed temperature in reactor 5 is 120℃;

[0220] (5) The waste liquid obtained in step (2) is transported to the solid-liquid separator 6 for solid-liquid separation, and the separated liquid phase is transported to the storage tank 8.

[0221] The gas at the outlet of reactor 5 was tested, and the dust concentration was less than or equal to 0.01 mg / m³. 3 The concentration of toluene is less than 8.6 mg / m³. 3 .

[0222] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for treating low-concentration VOCs waste gas containing dust, characterized in that, The method includes the following steps: (1) The waste gas to be treated, ozone and peroxide solution are mixed to obtain a mixture; (2) The mixture is transported to the circulating tower and treated under ultraviolet light to obtain waste liquid and gas phase. The gas phase is dehydrated to obtain gaseous material. (3) The gaseous material obtained in step (2) is subjected to catalytic oxidation and ozone decomposition reactions in sequence; In step (1), the weight ratio of VOCs to ozone in the waste gas to be treated is 1:5-20; In step (1), the concentration of peroxide in the peroxide solution is 1×10⁻⁶. -3 -10×10 -3 mol / L; The concentration of VOCs in the waste gas to be treated is 10-200 mg / m³. 3 The dust concentration is 10-100 mg / m³ 3 .

2. The method according to claim 1, characterized in that, The peroxide is selected from one or more of hydrogen peroxide, sodium persulfate, and potassium persulfate.

3. The method according to claim 1, characterized in that, The wavelength of the ultraviolet light is 180-328nm.

4. The method according to claim 1 or 3, characterized in that, The temperature during the dehydration process is 1-5℃.

5. The method according to claim 1, characterized in that, The catalytic oxidation reaction is carried out in the presence of a catalyst, which is a Co-Mn bimetallic catalyst.

6. The method according to claim 1 or 5, characterized in that, The ozone decomposition reaction is carried out in the presence of a catalyst, namely manganese dioxide.

7. The method according to claim 1 or 5, characterized in that, The temperature for catalytic oxidation reactions is 70-120℃.

8. The method according to claim 1, characterized in that, The temperature for ozone decomposition is 70-120℃.

9. The method according to claim 1, characterized in that, The method further includes: performing solid-liquid separation on the waste liquid.

10. A system for treating low-concentration VOCs waste gas containing dust, characterized in that, The system is used to implement the method according to any one of claims 1-9, the system comprising: a gas-liquid mixer (1), a circulation tower (2), a coalescer (4), a reactor (5), a solid-liquid separator (6), an ozone generator (7), and a storage tank (8); the circulation tower (2) is equipped with an ultraviolet lamp; The peroxide solution from the storage tank (8), the ozone from the ozone generator (7) and the waste gas to be treated are mixed in the gas-liquid mixer (1) to obtain a mixture; The mixture from the gas-liquid mixer (1) is processed in the circulating tower (2) to obtain a gas phase and waste liquid; The gas phase from the circulating tower (2) is dehydrated in the coalescer (4) to obtain gaseous material; The gaseous material from the coalescer (4) is subjected to catalytic oxidation and ozone decomposition reactions in the reactor (5) in sequence; Waste liquid from the circulating tower (2) is subjected to solid-liquid separation in the solid-liquid separator (6).

11. The system according to claim 10, characterized in that, The liquid outlet of the solid-liquid separator (6) is connected to the liquid storage tank (8).

12. The system according to claim 10, characterized in that, The power of the ultraviolet lamp is 10-30kW.

13. The system according to claim 10 or 12, characterized in that, A first centrifugal pump (9) is provided between the circulation tower (2) and the solid-liquid separator (6).

14. The system according to claim 10, characterized in that, A second centrifugal pump (3) is provided between the liquid storage tank (8) and the gas-liquid mixer (1).

15. The application of the method according to any one of claims 1-9 or the system according to any one of claims 10-14 in the treatment of VOCs waste gas.

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