A system and method for low temperature plasma catalytic treatment of organic exhaust gas

Abstract

The application relates to the technical field of waste gas treatment, and discloses a low-temperature plasma catalytic treatment system and method for organic waste gas. The system comprises a first reaction unit, a second reaction unit, a third reaction unit, an ozone generator (18) and a COx filter (19), wherein the first reaction unit is a plasma reactor connected with a high-voltage power supply, the second reaction unit comprises two or more plasma reactors connected with high-voltage power supplies, and the third reaction unit is a reactor provided with a transition metal oxide catalyst. According to the technical scheme, the degradation of VOCs in oxygen-poor waste gas can be realized at a lower operation cost and without changing the gas composition.

Description

Technical Field

[0001] This invention relates to the field of waste gas treatment technology, specifically to a low-temperature plasma catalytic treatment system and method for organic waste gas. Background Technology

[0002] Volatile organic compounds (VOCs) refer to organic compounds with a saturated vapor pressure greater than 70 Pa at room temperature and a boiling point below 260℃ at normal pressure, or all organic compounds with a vapor pressure greater than or equal to 10 Pa at 20℃ that are volatile. These include non-methane hydrocarbons, halogenated hydrocarbons, oxygen-containing organic compounds, nitrogen-containing organic compounds, and sulfur-containing organic compounds. Their main sources include industrial production processes such as organic chemical processing, petroleum refining, printing, spraying, and solvent use. VOCs are not only important precursors to smog and photochemical smog, but their irritating odors and biotoxicity also cause significant harm to human health.

[0003] Generally, methods for treating organic waste gas fall into two main categories. For high-concentration organic waste gas with recovery value, recovery technologies such as membrane separation, adsorption, and absorption are typically employed. For low-concentration organic waste gas without recovery value, destruction technologies such as regenerative thermal combustion, catalytic oxidation, biological methods, low-temperature plasma methods, and photocatalysis are commonly used. Organic waste gas destruction technology can be simply described as a series of physical, chemical, and biological reactions that cause VOCs to oxidize with oxygen in the air, ultimately mineralizing them into CO2 and H2O. Therefore, oxygen is a crucial reaction condition for VOCs degradation. Although most organic waste gas emitted during industrial production processes consists of air as a background, some processes and equipment generate organic waste gas with inert gases as the main background component, resulting in very low oxygen content. For example, in the first case, oxygen participates as one of the reactants in the organic synthesis reaction process, leading to a decrease in the oxygen content of the emitted organic waste gas; in the second case, inert gases serve as circulating protective gases to prevent the oxidation of organic products, and VOCs gradually accumulate in the inert circulating gas, which not only reduces product performance but also damages equipment performance.

[0004] For the first scenario of generating oxygen-deficient organic waste gas, VOCs degradation can be achieved by mixing with a certain amount of air and using destruction technology. However, the drawback is that larger volumes of waste gas require larger-scale treatment equipment. For the second scenario of generating oxygen-deficient organic waste gas, if a small amount of air is mixed with the waste gas and then destroyed, the VOCs degradation efficiency cannot be guaranteed. Furthermore, to prevent the oxidation of organic products, gas separation equipment is needed to control the increased oxygen concentration in the recirculating gas caused by the introduction of air. If adsorption technology is used to collect VOCs, additional waste gas enrichment treatment equipment or outsourcing the regeneration of the adsorbent to a relevant company is required.

[0005] In summary, using traditional methods or combinations of processes to degrade oxygen-deficient organic waste gas under both conditions significantly increases the cost of waste gas treatment. Therefore, how to control the cost of waste gas treatment while ensuring efficient degradation of VOCs has become an urgent problem to be solved in the treatment of oxygen-deficient organic waste gas. Summary of the Invention

[0006] The purpose of this invention is to provide a low-temperature plasma catalytic treatment system and method for organic waste gas. According to the technical solution of this invention, VOCs in organic waste gas can be effectively removed at a lower cost.

[0007] To achieve the above objectives, the present invention provides a low-temperature plasma catalytic treatment system for organic waste gas. The system includes a first reaction unit, a second reaction unit, a third reaction unit, an ozone generator, and a COx filter. The first reaction unit is a plasma reactor connected to a high-voltage power supply. The second reaction unit includes two or more plasma reactors connected to a high-voltage power supply. The third reaction unit is a reactor containing a transition metal oxide catalyst.

[0008] The gas supply source supplies the organic waste gas to be treated to the first reaction unit through a pipeline with valves, or supplies the organic waste gas to be treated to each reactor of the second reaction unit through a pipeline with valves.

[0009] The outlet of the first reaction unit is connected to the inlet of each reactor in the second reaction unit via pipelines equipped with valves.

[0010] The outlet of the ozone generator is connected to the inlet of each reactor in the second reaction unit via pipelines equipped with valves.

[0011] The outlets of each reactor in the second reaction unit are connected to the inlet of the third reaction unit via pipelines with valves, so that the gases discharged from each reactor in the second reaction unit can enter the third reaction unit individually or in combination.

[0012] The outlets of each reactor in the second reaction unit are connected to the inlet of the COx filter via pipelines with valves, so that the gas discharged from each reactor in the second reaction unit can enter the COx filter individually or in combination.

[0013] The outlet of the third reaction unit is connected to the inlet of the COx filter via a pipeline with a valve.

[0014] Preferably, the system further includes a total hydrocarbon analyzer for monitoring the total hydrocarbon concentration of the gas discharged from the outlet of each reactor of the second reaction unit, or for monitoring the total hydrocarbon concentration in the gas after the gases discharged from the outlet of each reactor of the second reaction unit are combined.

[0015] Preferably, the system further includes a first ozone analyzer for monitoring the ozone concentration of gases discharged from the outlets of each reactor in the second reaction unit.

[0016] Preferably, the system further includes a second ozone analyzer for monitoring the ozone concentration of the gas discharged from the outlet of the third reaction unit.

[0017] A second aspect of this invention provides a low-temperature plasma catalytic treatment method for organic waste gas, which is implemented in the aforementioned system, and the method includes:

[0018] (1) Determine the treatment requirements for organic waste gas, wherein the treatment requirements for organic waste gas include continued recycling after treatment or direct discharge after treatment;

[0019] (2) Determine the oxygen content of the organic waste gas;

[0020] (3) Depending on the treatment requirements and oxygen content of the organic waste gas, the organic waste gas is input into the system for treatment according to different operating schemes.

[0021] Preferably, when the treatment requirement for the organic waste gas is that the waste gas should be recycled after treatment, and the oxygen content of the organic waste gas is ≤1%,

[0022] (I) The organic waste gas in the gas supply source is supplied to the first reactor (2-1) in the second reaction unit for treatment, then processed through the COx filter, and then recycled back to the gas supply source for continued recycling.

[0023] (II) When the total hydrocarbon concentration at the outlet of the first reactor exceeds the emission standard, the organic waste gas from the gas supply source is supplied to the second reactor in the second reaction unit for treatment.

[0024] (III) Ozone is input into the first reactor through the ozone generator, and excess ozone discharged from the first reactor is processed in the third reaction unit. When the ozone concentration at the outlet of the first reactor is the same as the ozone concentration at the inlet, the input of ozone into the first reactor is stopped.

[0025] (IV) If the total hydrocarbon concentration at the outlet of the second reactor exceeds the emission standard, refer to steps (I) to (III) to supply the organic waste gas from the gas supply source to the first reactor or other reactor in the second reaction unit again, and input ozone into the second reactor through the ozone generator;

[0026] (V) Repeat steps (I) to (IV).

[0027] Preferably, when the treatment requirement for the organic waste gas is that the waste gas should be recycled after treatment, and the oxygen content of the organic waste gas is greater than 1% and less than or equal to 10%,

[0028] (I) The organic waste gas from the gas supply source is supplied to the first reaction unit for treatment;

[0029] (II) The organic waste gas discharged from the first reaction unit is transported to the first reactor in the second reaction unit for treatment, then processed through the COx filter, and then recycled back to the gas supply source for continued recycling.

[0030] (III) When the total hydrocarbon concentration at the outlet of the first reactor exceeds the emission standard, the organic waste gas discharged from the first reaction unit is transported to the second reactor in the second reaction unit for treatment.

[0031] (IV) Ozone is input into the first reactor through the ozone generator, and excess ozone discharged from the first reactor is processed in the third reaction unit. When the ozone concentration at the outlet of the first reactor is the same as the ozone concentration at the inlet, the input of ozone into the first reactor is stopped.

[0032] (V) If the total hydrocarbon concentration at the outlet of the second reactor exceeds the emission standard, refer to steps (II) to (IV) to supply the organic waste gas discharged from the first reaction unit to the first reactor or other reactor in the second reaction unit again, and input ozone into the second reactor through the ozone generator;

[0033] (VI) Repeat steps (II) to (V).

[0034] Preferably, when the treatment requirement for the organic waste gas is that the waste gas should be recycled after treatment, and the oxygen content of the organic waste gas is greater than 10% and less than or equal to 20%,

[0035] (I) The organic waste gas from the gas supply source is supplied to the first reaction unit for treatment;

[0036] (II) The organic waste gas discharged from the first reaction unit is transported to the first reactor in the second reaction unit for treatment, and then transported to the third reaction unit for treatment. It is then processed through the COx filter and then recycled back to the gas supply source for further processing.

[0037] (III) When the total hydrocarbon concentration at the outlet of the first reactor exceeds the emission standard, the organic waste gas discharged from the first reaction unit is transported to the second reactor in the second reaction unit for treatment.

[0038] (IV) Ozone is input into the first reactor through the ozone generator, and excess ozone discharged from the first reactor is processed in the third reaction unit. When the ozone concentration at the outlet of the first reactor is the same as the ozone concentration at the inlet, the input of ozone into the first reactor is stopped.

[0039] (V) If the total hydrocarbon concentration at the outlet of the second reactor exceeds the emission standard, refer to steps (II) to (IV) to supply the organic waste gas discharged from the first reaction unit to the first reactor or other reactor in the second reaction unit again, and input ozone into the second reactor through the ozone generator;

[0040] (VI) Repeat steps (II) to (V).

[0041] Preferably, when the treatment requirement for the organic waste gas is that it is directly discharged after treatment, and the oxygen content of the organic waste gas is ≤1%,

[0042] (I) The organic waste gas in the gas supply source is supplied to all the reactors in the second reaction unit for treatment, and ozone is introduced into all the reactors in the second reaction unit through the ozone generator.

[0043] (II) When the total hydrocarbon concentration of the mixed gas discharged from the second reaction unit exceeds the emission standard, increase the ozone intake concentration or flow rate, or increase the discharge voltage of each reactor in the second reaction unit until the total hydrocarbon concentration of the mixed gas is lower than the emission standard.

[0044] Preferably, when the treatment requirement for the organic waste gas is that it is directly discharged after treatment, and the oxygen content of the organic waste gas is greater than 1% and less than or equal to 10%,

[0045] (I) The organic waste gas from the gas supply source is supplied to the first reaction unit for treatment;

[0046] (II) The organic waste gas discharged from the first reaction unit is respectively transported to all reactors in the second reaction unit for treatment, and ozone is respectively introduced into all reactors in the second reaction unit through the ozone generator;

[0047] (III) When the total hydrocarbon concentration of the mixed gas discharged from the second reaction unit exceeds the emission standard, increase the ozone intake concentration or flow rate, or increase the discharge voltage of each reactor in the second reaction unit until the total hydrocarbon concentration of the mixed gas is lower than the emission standard.

[0048] Preferably, when the treatment requirement for the organic waste gas is that it is directly discharged after treatment, and the oxygen content of the organic waste gas is greater than 10% and less than or equal to 20%,

[0049] (I) The organic waste gas from the gas supply source is supplied to the first reaction unit for treatment;

[0050] (II) The organic waste gas discharged from the first reaction unit is respectively transported to all reactors in the second reaction unit for treatment;

[0051] (III) When the total hydrocarbon concentration of the mixed gas discharged from the second reaction unit exceeds the emission standard, increase the discharge voltage of each reactor in the second reaction unit, or input ozone into all reactors in the second reaction unit through the ozone generator and adjust the ozone intake concentration or flow rate until the total hydrocarbon concentration of the mixed gas is lower than the emission standard.

[0052] Preferably, the reactor of the first reaction unit is filled with ferroelectric material.

[0053] Preferably, the ferroelectric material is a natural crystal and / or a synthetic crystal, wherein the natural crystal is at least one of barium titanate, potassium dihydrogen phosphate and sodium nitrite, and the synthetic crystal is a crystal with further enhanced polarization under a high voltage electric field obtained by modifying the natural crystal.

[0054] Preferably, the reactor of the second reaction unit is filled with a first transition metal oxide catalyst. In the first transition metal oxide catalyst, the active component is a transition metal oxide, wherein the transition metal is one or any combination of at least two of Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu and Zn, and the support is alumina, activated carbon, molecular sieve or MOFs.

[0055] Preferably, the reactor of the third reaction unit is filled with a second transition metal oxide catalyst. In the second transition metal oxide catalyst, the active component is a transition metal oxide, wherein the transition metal is one or any combination of at least two of Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu and Zn, and the support is alumina, activated carbon, molecular sieve or MOFs.

[0056] According to the technical solution of the present invention, in the first reaction unit, oxygen in organic waste gas can be converted into NO, and preliminary degradation of VOCs can be achieved; in the second reaction unit, in the presence of a transition metal oxide catalyst, VOCs or VOCs degradation byproducts are adsorbed on the catalyst surface. During plasma discharge, they can react with NO and ozone generated in the first reaction unit, as well as with lattice oxygen in the transition metal oxide, to achieve VOCs degradation. Furthermore, the ozone provided by the ozone generator can be used to regenerate the transition metal oxide catalyst in the second reaction unit and allow for its alternating use; in the third reaction unit, NOx (such as N2O, NO, NO2, N2O3, N2O4, N2O5, etc.) and ozone generated or emitted during the VOCs degradation process in the second reaction unit can be decomposed into nitrogen and oxygen. Therefore, in this invention, NO and ozone are used instead of oxygen as active oxygen donors in the plasma catalytic degradation of VOCs, which improves the reaction efficiency. Moreover, by using lattice oxygen in transition metal oxides as active oxygen donors in the plasma catalytic degradation of VOCs under oxygen-deficient systems, and using ozone as a means to quickly replenish lattice oxygen, the problem of removing VOCs from oxygen-deficient waste gas without increasing impurities is solved.

[0057] Compared with the prior art, the beneficial effects of the present invention are mainly reflected in: (1) Ozone and NO are used to replace oxygen, which can improve the oxygen utilization efficiency of the second reaction unit and further improve the VOCs degradation efficiency; (2) Ozone generator is used to replace the fan for oxygen supply, which reduces investment costs; the second reaction unit has a higher utilization efficiency of ozone than oxygen, and only a small amount of ozone is needed to achieve VOCs degradation and catalyst regeneration, which reduces operating costs; (3) Through the operation scheme provided by the present invention, VOCs in oxygen-deficient waste gas can be degraded at a lower operating cost and without changing the gas composition. Attached Figure Description

[0058] Figure 1 This is a schematic diagram of the low-temperature plasma catalytic treatment system for organic waste gas according to the present invention;

[0059] Figure 2 This is a chart showing the parameters of each device in the system during the operation of Example 1;

[0060] Figure 3This is a chart showing the parameters of each device in the system during the operation of Example 2;

[0061] Figure 4 This is a chart showing the parameters of each device in the system during the operation of Example 3;

[0062] Figure 5 This is a chart showing the parameters of each device in the system during the operation of Example 4;

[0063] Figure 6 This is a chart showing the parameters of each device in the system during the operation of Example 5;

[0064] Figure 7 This is a chart showing the parameters of each device in the system during the operation of Example 6.

[0065] Explanation of reference numerals in the attached figures

[0066] 1. Reactor of the first reaction unit; 2-1. First reactor; 2-2. Second reactor; 3. Reactor of the third reaction unit; 18. Ozone generator; 19. COx filter; 20. Total hydrocarbon analyzer; 21. First ozone analyzer; 22. Second ozone analyzer;

[0067] 01, 2, 03, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17: Valves. Detailed Implementation

[0068] 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.

[0069] 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.

[0070] like Figure 1 As shown, the low-temperature plasma catalytic treatment system for organic waste gas of the present invention includes a first reaction unit, a second reaction unit, a third reaction unit, an ozone generator 18, and a filter 19. The filter 19 is used to adsorb COx (including CO and CO2) from the gas and is also called a COx filter.

[0071] In the system described in this invention, the first reaction unit includes a reactor, namely reactor 1. Reactor 1 is a plasma reactor connected to a high-voltage power supply. In a preferred embodiment, the discharge region within reactor 1 is filled with a ferroelectric material. The ferroelectric material can be a natural crystal and / or a synthetic crystal, wherein the natural crystal is preferably at least one of barium titanate, potassium dihydrogen phosphate, and sodium nitrite, and the synthetic crystal can be a crystal with further enhanced polarization under a high-voltage electric field, obtained by modifying the aforementioned natural crystal. The function of reactor 1 is to enhance the electric field by embedding ferroelectric material within the plasma, thereby improving the reaction efficiency of oxygen to NO conversion in organic waste gas, and simultaneously achieving the initial degradation of VOCs.

[0072] In the system described in this invention, the second reaction unit includes two or more plasma reactors connected to a high-voltage power supply. Each reactor in the second reaction unit has a discharge zone filled with a first transition metal oxide catalyst. Preferably, the active component in the first transition metal oxide catalyst is a transition metal oxide, wherein the transition metal is one or more of Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn, or any combination of two or more of these. The support is alumina, activated carbon, molecular sieves, or MOFs. The function of the second reaction unit is to: ① adsorb VOCs or VOCs degradation byproducts onto the catalyst surface, so that during plasma discharge, they can react with NO and ozone provided by the first reaction unit, as well as with lattice oxygen in the transition metal oxide, to achieve VOCs degradation; ② regenerate the catalyst using ozone provided by the first reaction unit during plasma discharge. In one specific embodiment, the second reaction unit includes two reactors, namely, a first reactor 2-1 and a second reactor 2-2.

[0073] In the system described in this invention, the third reaction unit includes a reactor, namely reactor 3. Reactor 3 is a reactor containing a second transition metal oxide catalyst. Preferably, in the second transition metal oxide catalyst, the active component is a transition metal oxide, wherein the transition metal is one or any combination of at least two of Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn, and the support is alumina, activated carbon, molecular sieves, or MOFs. The function of the third reaction unit is to decompose the NOx and ozone generated or emitted during the VOCs degradation process in the second reaction unit into nitrogen and oxygen.

[0074] In this invention, the first transition metal oxide catalyst and the second transition metal oxide catalyst may be the same or different, preferably different. In one specific embodiment, the catalyst packed in each reactor of the second reaction unit is Ce. 0.6 Co0.4 The catalyst packed in the reactor of the third reaction unit is MnO2 / activated carbon, which is O2 / molecular sieve.

[0075] In the system described in this invention, the reactors of the first reaction unit and each reactor of the second reaction unit are plasma reactors. Specifically, the plasma reactors can be conventional reactors used to generate dielectric barrier discharges. According to the number of barrier media, they can be divided into single dielectric barrier discharge plasma reactors and double dielectric barrier discharge plasma reactors; according to the electrode shape, they can be divided into tube-type plasma reactors, plate-type plasma reactors, shaft-type plasma reactors, needle-plate-type plasma reactors, etc.; and other reactor types.

[0076] In the system described in this invention, the plasma reactor is connected to a high-voltage power supply. Specifically, the high-voltage power supply can be a conventional power supply used in the art to drive plasma discharge, such as a power frequency AC power supply, a high frequency AC power supply, a nanosecond pulse power supply, a unipolar / bipolar pulse power supply, a narrow pulse power supply, etc.

[0077] In the system described in this invention, the ozone concentration and flow rate of the ozone generator 18 are adjustable. The function of the ozone generator is to provide a small amount of ozone required for the degradation of VOCs in the second reaction unit.

[0078] In the system described in this invention, the COx filter 19 is a reactor containing a COx adsorbent. The COx adsorbent can be activated carbon, carbon molecular sieves, zeolite molecular sieves, carbon nanotubes, MOFs, etc., or the aforementioned modified materials whose COx adsorption capacity is enhanced through various physicochemical reactions. The function of the COx filter 19 is to filter COx, the final product of the plasma degradation reaction of VOCs, when treating VOCs in oxygen-deficient waste gas and requiring control of impurity content in the gas.

[0079] In the system described in this invention, a gas supply source supplies the organic waste gas to be treated to the first reaction unit via a pipeline with valves, or supplies the organic waste gas to be treated to each reactor of the second reaction unit via a pipeline with valves; the outlet of the first reaction unit is connected to the inlet of each reactor of the second reaction unit via a pipeline with valves; the outlet of the ozone generator 18 is connected to the inlet of each reactor of the second reaction unit via a pipeline with valves; the outlets of each reactor of the second reaction unit are connected to the inlet of the third reaction unit via pipelines with valves, so that the gas discharged from each reactor of the second reaction unit can enter the third reaction unit individually or in combination; the outlets of each reactor of the second reaction unit are connected to the inlet of the COx filter 19 via pipelines with valves, so that the gas discharged from each reactor of the second reaction unit can enter the COx filter 19 individually or in combination; the outlet of the third reaction unit is connected to the inlet of the COx filter 19 via a pipeline with valves.

[0080] In a preferred embodiment, the system of the present invention further includes a total hydrocarbon analyzer 20, used to monitor the total hydrocarbon concentration of the gas discharged from the outlet of each reactor of the second reaction unit, or to monitor the total hydrocarbon concentration in the gas after the gas discharged from the outlet of each reactor of the second reaction unit is combined.

[0081] In a preferred embodiment, the system of the present invention further includes a first ozone analyzer 21 for monitoring the ozone concentration of gases discharged from the outlets of each reactor in the second reaction unit.

[0082] In a preferred embodiment, the system of the present invention further includes a second ozone analyzer 22 for monitoring the ozone concentration of the gas discharged from the outlet of the third reaction unit.

[0083] According to a specific embodiment of the present invention, in the system of the present invention, the second reaction unit includes a first reactor 2-1 and a second reactor 2-2. A valve 2 is installed on the connecting pipeline between the gas supply source and the inlet of reactor 1 (i.e., the reactor of the first reaction unit). The outlet of reactor 1 is connected to the inlets of the first reactor 2-1 and the second reactor 2-2 respectively through pipelines. Valve 03 and valve 4 are installed sequentially on the connecting pipeline between the outlet of reactor 1 and the inlet of the first reactor 2-1, and valve 03 and valve 5 are installed sequentially on the connecting pipeline between the outlet of reactor 1 and the inlet of the second reactor 2-2.

[0084] The gas supply source is also connected to the inlet of the first reactor 2-1 and the second reactor 2-2 via pipelines. Specifically, valves 01 and 4 are installed in sequence on the connecting pipeline between the gas supply source and the inlet of the first reactor 2-1, and valves 01 and 5 are installed in sequence on the connecting pipeline between the gas supply source and the inlet of the second reactor 2-2.

[0085] The outlet of ozone generator 18 is connected to the inlet of the first reactor 2-1 and the inlet of the second reactor 2-2 via pipelines. A valve 6 is installed on the connecting pipeline between the outlet of ozone generator 18 and the inlet of the first reactor 2-1, and a valve 7 is installed on the connecting pipeline between the outlet of ozone generator 18 and the inlet of the second reactor 2-2.

[0086] The outlets of the first reactor 2-1 and the second reactor 2-2 are respectively connected to the inlet of reactor 3 (i.e., the reactor of the third reaction unit) through pipelines. A valve 10 is installed on the connecting pipeline between the outlet of the first reactor 2-1 and the inlet of reactor 3, and a valve 11 is installed on the connecting pipeline between the outlet of the second reactor 2-2 and the inlet of reactor 3.

[0087] The outlets of the first reactor 2-1 and the second reactor 2-2 are respectively connected to the inlet of the COx filter 19 through pipelines. A valve 8 is installed on the connecting pipeline between the outlet of the first reactor 2-1 and the inlet of the COx filter 19, and a valve 9 is installed on the connecting pipeline between the outlet of the second reactor 2-2 and the inlet of the COx filter 19.

[0088] A valve 12 is installed on the connecting pipeline between the outlet of the first reactor 2-1 and the inlet of the total hydrocarbon analyzer 20;

[0089] A valve 13 is installed on the connecting pipeline between the outlet of the second reactor 2-2 and the inlet of the total hydrocarbon analyzer 20;

[0090] Valve 14 is installed on the connecting pipeline between the gas inlet section of reactor 3 (located downstream of the streams from valves 10 and 11) and the inlet of total hydrocarbon analyzer 20.

[0091] A valve 15 is installed on the pipeline between the outlet of the first reactor 2-1 and the inlet of the first ozone analyzer 21;

[0092] A valve 16 is installed on the pipeline between the outlet of the second reactor 2-2 and the inlet of the first ozone analyzer 21;

[0093] A valve 17 is installed on the connecting pipeline between the outlet of reactor 3 and the inlet of COx filter 19.

[0094] According to the configuration scheme of the above specific implementation method, by controlling each valve, a suitable combination of schemes can be selected from the operation of the first reaction unit, the second reaction unit and the third reaction unit according to the different organic waste gas treatment requirements (recirculation or emission) and oxygen content, so as to achieve efficient degradation of VOCs at low cost.

[0095] This invention also provides a low-temperature plasma catalytic treatment method for organic waste gas, which is implemented in the system described above, and the method includes:

[0096] (1) Determine the treatment requirements for organic waste gas, wherein the treatment requirements for organic waste gas include continued recycling after treatment or direct discharge after treatment;

[0097] (2) Determine the oxygen content of the organic waste gas;

[0098] (3) Depending on the treatment requirements and oxygen content of the organic waste gas, the organic waste gas is input into the system for treatment according to different operating schemes.

[0099] According to a first embodiment of the method of the present invention, when the treatment requirement of the organic waste gas is that the waste gas should be recycled after treatment, and the oxygen content of the organic waste gas is ≤1%,

[0100] (I) The organic waste gas in the gas supply source is supplied to the first reactor 2-1 in the second reaction unit for treatment, and then processed through the COx filter 19, and then recycled back to the gas supply source for continued recycling.

[0101] (II) When the total hydrocarbon concentration at the outlet of the first reactor 2-1 exceeds the emission standard, the organic waste gas in the gas supply source is supplied to the second reactor 2-2 in the second reaction unit for treatment;

[0102] (III) Ozone is input into the first reactor 2-1 through the ozone generator 18, and the excess ozone discharged from the first reactor 2-1 is processed in the third reaction unit. When the ozone concentration at the outlet of the first reactor 2-1 is the same as the ozone concentration at the inlet, the input of ozone into the first reactor 2-1 is stopped.

[0103] (IV) If the total hydrocarbon concentration at the outlet of the second reactor 2-2 exceeds the emission standard, refer to steps (I) to (III) to supply the organic waste gas in the gas supply source to the first reactor 2-1 or other reactors in the second reaction unit again (if the second reaction unit has three or more reactors, other reactors can be selected), and input ozone into the second reactor 2-2 through the ozone generator 18.

[0104] (V) Repeat steps (I) to (IV).

[0105] According to a second embodiment of the method of the present invention, when the treatment requirement of the organic waste gas is that the waste gas should be recycled after treatment, and the oxygen content of the organic waste gas is greater than 1% and less than or equal to 10%,

[0106] (I) The organic waste gas from the gas supply source is supplied to the first reaction unit for treatment;

[0107] (II) The organic waste gas discharged from the first reaction unit is transported to the first reactor 2-1 in the second reaction unit for treatment, then processed through the COx filter 19, and then recycled back to the gas supply source for continued recycling.

[0108] (III) When the total hydrocarbon concentration at the outlet of the first reactor 2-1 exceeds the emission standard, the organic waste gas discharged from the first reaction unit is transported to the second reactor 2-2 in the second reaction unit for treatment;

[0109] (IV) Ozone is input into the first reactor 2-1 through the ozone generator 18, and the excess ozone discharged from the first reactor 2-1 is processed in the third reaction unit. When the ozone concentration at the outlet of the first reactor 2-1 is the same as the ozone concentration at the inlet, the input of ozone into the first reactor 2-1 is stopped.

[0110] (V) If the total hydrocarbon concentration at the outlet of the second reactor 2-2 exceeds the emission standard, refer to steps (II) to (IV) to supply the organic waste gas discharged from the first reaction unit to the first reactor 2-1 or other reactors in the second reaction unit (if the second reaction unit has three or more reactors, other reactors may be selected), and input ozone into the second reactor 2-2 through the ozone generator 18.

[0111] (VI) Repeat steps (II) to (V).

[0112] According to a third embodiment of the method of the present invention, when the treatment requirement of the organic waste gas is that the waste gas should be recycled after treatment, and the oxygen content of the organic waste gas is greater than 10% and less than or equal to 20%,

[0113] (I) The organic waste gas from the gas supply source is supplied to the first reaction unit for treatment;

[0114] (II) The organic waste gas discharged from the first reaction unit is transported to the first reactor 2-1 in the second reaction unit for treatment, and then transported to the third reaction unit for treatment. It is then processed through the COx filter 19 and then recycled back to the gas supply source for further processing.

[0115] (III) When the total hydrocarbon concentration at the outlet of the first reactor 2-1 exceeds the emission standard, the organic waste gas discharged from the first reaction unit is transported to the second reactor 2-2 in the second reaction unit for treatment;

[0116] (IV) Ozone is input into the first reactor 2-1 through the ozone generator 18, and the excess ozone discharged from the first reactor 2-1 is processed in the third reaction unit. When the ozone concentration at the outlet of the first reactor 2-1 is the same as the ozone concentration at the inlet, the input of ozone into the first reactor 2-1 is stopped.

[0117] (V) If the total hydrocarbon concentration at the outlet of the second reactor 2-2 exceeds the emission standard, refer to steps (II) to (IV) to supply the organic waste gas discharged from the first reaction unit to the first reactor 2-1 or other reactors in the second reaction unit (if the second reaction unit has three or more reactors, other reactors may be selected), and input ozone into the second reactor 2-2 through the ozone generator 18.

[0118] (VI) Repeat steps (II) to (V).

[0119] According to a fourth embodiment of the method of the present invention, when the treatment requirement of the organic waste gas is that the waste gas is treated and then directly discharged, and the oxygen content of the organic waste gas is ≤1%,

[0120] (I) The organic waste gas in the gas supply source is supplied to all the reactors in the second reaction unit for treatment, and ozone is introduced into all the reactors in the second reaction unit through the ozone generator 18.

[0121] (II) When the total hydrocarbon concentration of the mixed gas discharged from the second reaction unit exceeds the emission standard, increase the ozone intake concentration or flow rate, or increase the discharge voltage of each reactor in the second reaction unit until the total hydrocarbon concentration of the mixed gas is lower than the emission standard.

[0122] According to a fifth embodiment of the method of the present invention, when the treatment requirement of the organic waste gas is that the waste gas is treated and then directly discharged, and the oxygen content of the organic waste gas is greater than 1% and less than or equal to 10%,

[0123] (I) The organic waste gas from the gas supply source is supplied to the first reaction unit for treatment;

[0124] (II) The organic waste gas discharged from the first reaction unit is respectively transported to all reactors in the second reaction unit for treatment, and ozone is respectively input into all reactors in the second reaction unit through the ozone generator 18;

[0125] (III) When the total hydrocarbon concentration of the mixed gas discharged from the second reaction unit exceeds the emission standard, increase the ozone intake concentration or flow rate, or increase the discharge voltage of each reactor in the second reaction unit until the total hydrocarbon concentration of the mixed gas is lower than the emission standard.

[0126] According to a sixth embodiment of the method of the present invention, when the treatment requirement of the organic waste gas is that the waste gas is treated and then directly discharged, and the oxygen content of the organic waste gas is greater than 10% and less than or equal to 20%,

[0127] (I) The organic waste gas from the gas supply source is supplied to the first reaction unit for treatment;

[0128] (II) The organic waste gas discharged from the first reaction unit is respectively transported to all reactors in the second reaction unit for treatment;

[0129] (III) When the total hydrocarbon concentration of the mixed gas discharged from the second reaction unit exceeds the emission standard, increase the discharge voltage of each reactor in the second reaction unit, or input ozone into all reactors in the second reaction unit through the ozone generator (18) and adjust the ozone intake concentration or flow rate until the total hydrocarbon concentration of the mixed gas is lower than the emission standard.

[0130] This invention is primarily used for the treatment of oxygen-deficient organic waste gas emitted from industries such as petroleum and chemical engineering, and is particularly suitable for removing VOCs from oxygen-deficient waste gas. Based on the principle of plasma catalytic reaction, ozone, NO, and lattice oxygen (transition metal oxides) are used instead of oxygen as the source of active oxygen for the reaction with VOCs on the catalyst surface, effectively improving the degradation efficiency of VOCs. Simultaneously, the blower used for oxygen supply is replaced by an ozone generator, significantly reducing treatment costs.

[0131] The following examples further illustrate the low-temperature plasma catalytic treatment system and method for organic waste gas 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.

[0132] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods in the art. Unless otherwise specified, the experimental materials used in the following embodiments are commercially available.

[0133] Example 1

[0134] Treatment of oxygen-deficient (0.1% oxygen content) circulating gas containing VOCs.

[0135] The gas being treated is an inert circulating protective gas introduced to prevent the oxidation of organic products. The gas composition includes nitrogen (99.9%), oxygen (0.1%), and isopentane (the concentration gradually increases with the number of cycles; after one cycle, the concentration of isopentane in the circulating gas can reach 120-150 ppm). The gas flow rate is 100 m³ / s. 3 / h.

[0136] according to Figure 1 The main process parameters of the described waste gas treatment device are: the ozone generator output ozone concentration is 0-100%, and the output gas volume is 0-10 m³ / s. 3 / h; The first reactor 2-1 and the second reactor 2-2 are designed identically, both employing arrayed axial-tube plasma generators with an electrode gap of 6mm, high-frequency AC power supplies, and a discharge space of 1.8m. 3 The discharge region is filled with spherical Ce with a diameter of 2-3 mm. 0.6 Co 0.4 O2 / molecular sieve; reactor 3 is filled with 1m³ of O2 / molecular sieve. 3 MnO2 / activated carbon; COx filter filled with 0.4m³ 3 The modified MOFs exhibit significantly enhanced COx adsorption capacity, and as COx adsorption accumulates, the material surface undergoes a color change reaction (turning red when adsorption saturates).

[0137] When the recirculated gas is introduced into the waste gas treatment device, the operating procedure is as follows:

[0138] (1) Open valve 01, close valves 2 and 03, and short-circuit reactor 1;

[0139] (2) Open valves 4 and 8, and close valves 5, 9, 10 and 11 to allow circulating gas to enter the first reactor 2-1. The discharge voltage of the first reactor 2-1 is set to 18kV.

[0140] (3) Open valve 12, close valves 13 and 14, and monitor the total hydrocarbon change at the outlet of the first reactor 2-1;

[0141] (4) Monitor the color change of the adsorbent in the COx filter and close valves 6, 7, 15, 16 and 17;

[0142] (5) When the total hydrocarbon concentration exceeds 10 ppm (assuming the emission concentration meets the standard of 10 ppm), close valves 4 and 8, open valves 5 and 9, and allow the circulating gas to enter the second reactor 2-2. The discharge voltage of the second reactor 2-2 is set to 18 kV.

[0143] (6) Open valve 13, close valves 12 and 14, and monitor the total hydrocarbon change at the outlet of the second reactor 2-2;

[0144] (7) Turn on the ozone generator, adjust the ozone concentration to 200 ppm and the gas flow rate to 3 m³ / h. 3 / h, open valves 6 and 10 to allow ozone to enter the first reactor 2-1, and excess ozone enters reactor 3 for decomposition;

[0145] (8) Open valve 15, close valve 16, monitor the ozone change at the outlet of the first reactor 2-1, and when the ozone concentration at the inlet / outlet of the first reactor 2-1 is the same, turn off the ozone generator and close valve 6 and valve 10 at the same time.

[0146] (9) When the total hydrocarbon concentration exceeds 10 ppm, refer to steps 2-8, and switch valves 4-16 to allow the circulating gas to re-enter the first reactor 2-1, while the ozone enters the second reactor 2-2. The total hydrocarbon analyzer monitors the total hydrocarbon at the outlet of the first reactor 2-1, and the ozone analyzer monitors the ozone at the outlet of the second reactor 2-2.

[0147] (10) Repeating steps 2-9 can achieve the standard degradation of isopentane, while ensuring that the CO2 generated during the isopentane degradation process will not accumulate in the circulating gas.

[0148] (11) When the ozone concentration at the outlet of reactor 3 exceeds 10 ppm and all the material surfaces in the COx filter turn red, replace or regenerate the catalyst and adsorbent in reactor 3 and COx filter.

[0149] Note: In this embodiment, except for Figure 1 In addition to the indicated monitoring equipment, key parameters such as isopentane concentration, ozone concentration, COx concentration, and NOx concentration were measured at the inlet and outlet of each reactor. Detailed data, such as... Figure 2 As shown.

[0150] Example 2

[0151] Treatment of oxygen-deficient (6% oxygen content) circulating gas containing VOCs.

[0152] The gas being treated is an inert circulating protective gas introduced to prevent the oxidation of organic products. The gas composition includes nitrogen (94%), oxygen (6%), and ethyl acetate (the concentration gradually increases with the number of cycles; after one cycle, the concentration of ethyl acetate in the circulating gas can reach 110-160 ppm). The gas flow rate is 120 m³ / s.3 / h.

[0153] according to Figure 1 The main process parameters of the described waste gas treatment device are as follows: Reactor 1 adopts an array-distributed axial-cylinder plasma generator with an electrode gap of 5mm, a high-frequency AC power supply, and a discharge space of 1.2m. 3 The discharge area is filled with spherical barium titanate particles with a diameter of 1-2 mm; the ozone generator outputs an ozone concentration of 0-100% and an output gas volume of 0-10 m³ / s. 3 / h; The first reactor 2-1 and the second reactor 2-2 are designed identically, both employing arrayed axial-tube plasma generators with an electrode gap of 6mm, high-frequency AC power supplies, and a discharge space of 1.8m. 3 The discharge region is filled with spherical Ce with a diameter of 2-3 mm. 0.6 Co 0.4 O2 / molecular sieve; reactor 3 is filled with 1m³ of O2 / molecular sieve. 3 MnO2 / activated carbon; COx filter filled with 0.4m³ 3 The modified MOFs exhibit significantly enhanced COx adsorption capacity, and as COx adsorption accumulates, the material surface undergoes a color change reaction (turning red when adsorption saturates).

[0154] When the recirculated gas is introduced into the waste gas treatment device, the operating procedure is as follows:

[0155] (1) Open valve 2 and valve 03, close valve 01, so that the circulating gas enters reactor 1 first, and the discharge voltage of reactor 1 is set to 16kV.

[0156] (2) Open valves 4 and 8, and close valves 5, 9, 10 and 11 to allow circulating gas to enter the first reactor 2-1. The discharge voltage of the first reactor 2-1 is set to 18kV.

[0157] (3) Open valve 12, close valves 13 and 14, and monitor the total hydrocarbon change at the outlet of the first reactor 2-1;

[0158] (4) Monitor the color change of the adsorbent in the COx filter and close valves 6, 7, 15, 16 and 17;

[0159] (5) When the total hydrocarbon concentration exceeds 10 ppm (assuming the emission concentration meets the standard of 10 ppm), close valves 4 and 8, open valves 5 and 9, and allow the circulating gas to enter the second reactor 2-2. The discharge voltage of the second reactor 2-2 is set to 18 kV.

[0160] (6) Open valve 13, close valves 12 and 14, and monitor the total hydrocarbon change at the outlet of the second reactor 2-2;

[0161] (7) Turn on the ozone generator and adjust the ozone concentration to 150 ppm and the gas flow rate to 2 m³ / h. 3 / h, open valves 6 and 10 to allow ozone to enter the first reactor 2-1, and excess ozone enters reactor 3 for decomposition;

[0162] (8) Open valve 15, close valve 16, monitor the ozone change at the outlet of the first reactor 2-1, and when the ozone concentration at the inlet / outlet of the first reactor 2-1 is the same, turn off the ozone generator.

[0163] (9) When the total hydrocarbon concentration exceeds 10 ppm, refer to steps 2-8, and switch valves 4-16 to allow the circulating gas to re-enter the first reactor 2-1, while the ozone enters the second reactor 2-2. The total hydrocarbon analyzer monitors the total hydrocarbon at the outlet of the first reactor 2-1, and the ozone analyzer monitors the ozone at the outlet of the second reactor 2-2.

[0164] (10) Referring to steps 2-9, ethyl acetate can be degraded to meet the standards, while ensuring that the CO2 generated during the ethyl acetate oxidation degradation process will not accumulate in the circulating gas.

[0165] (11) When the ozone concentration at the outlet of reactor 3 exceeds 10 ppm and all the material surfaces in the COx filter turn red, replace or regenerate the catalyst and adsorbent in reactor 3 and COx filter.

[0166] Note: In this embodiment, except for Figure 1 In addition to the indicated monitoring equipment, key parameters such as ethyl acetate concentration, ozone concentration, COx concentration, and NOx concentration were measured at the inlet and outlet of each reactor. Detailed data, such as... Figure 3 As shown.

[0167] Example 3

[0168] Treatment of oxygen-deficient (11% oxygen content) circulating gas containing VOCs.

[0169] The gas being treated is an inert circulating protective gas introduced to prevent the oxidation of organic products. The gas composition includes nitrogen (87%), oxygen (13%), and isopentane (the concentration gradually increases with the number of cycles; after one cycle, the concentration of isopentane in the circulating gas can reach 110-150 ppm). The gas flow rate is 170 m³ / s. 3 / h.

[0170] according to Figure 1 The main process parameters of the described waste gas treatment device are as follows: Reactor 1 adopts an array-distributed axial-cylinder plasma generator with an electrode gap of 5mm, a high-frequency AC power supply, and a discharge space of 1.2m. 3The discharge area is filled with spherical barium titanate particles with a diameter of 1-2 mm; the ozone generator outputs an ozone concentration of 0-100% and an output gas volume of 0-10 m³ / s. 3 / h; The first reactor 2-1 and the second reactor 2-2 are designed identically, both employing arrayed axial-tube plasma generators with an electrode gap of 6mm, high-frequency AC power supplies, and a discharge space of 1.8m. 3 The discharge region is filled with spherical Ce with a diameter of 2-3 mm. 0.6 Co 0.4 O2 / molecular sieve; reactor 3 is filled with 1m³ of O2 / molecular sieve. 3 MnO2 / activated carbon; COx filter filled with 0.4m³ 3 The modified MOFs exhibit significantly enhanced COx adsorption capacity, and as COx adsorption accumulates, the material surface undergoes a color change reaction (turning red when adsorption saturates).

[0171] When the recirculated gas is introduced into the waste gas treatment device, the operating procedure is as follows:

[0172] (1) Open valve 2 and valve 03, close valve 01, so that the circulating gas enters reactor 1 first, and the discharge voltage of reactor 1 is set to 16kV.

[0173] (2) Open valves 4, 10 and 17, and close valves 5, 8, 9 and 11 to allow the circulating gas to enter the first reactor 2-1, reactor 3 and COx filter in sequence. The discharge voltage of the first reactor 2-1 is set to 18kV.

[0174] (3) Open valve 12, close valves 13 and 14, and monitor the total hydrocarbon change at the outlet of the first reactor 2-1;

[0175] (4) Monitor the color change of the adsorbent in the COx filter and close valves 6, 7, 15 and 16;

[0176] (5) When the total hydrocarbon concentration exceeds 10 ppm (assuming the emission concentration meets the standard of 10 ppm), close valve 4 and open valve 5 and valve 11 to allow the circulating gas to enter the second reactor 2-2, reactor 3 and COx filter in sequence. The discharge voltage of the second reactor 2-2 is set to 18 kV.

[0177] (6) Open valve 13, close valves 12 and 14, and monitor the total hydrocarbon change at the outlet of the second reactor 2-2;

[0178] (7) Turn on the ozone generator and adjust the ozone concentration to 100ppm and the gas flow rate to 1m³. 3 / h, open valves 6 and 10 to allow ozone to enter the first reactor 2-1, and excess ozone enters reactor 3 for decomposition;

[0179] (8) Open valve 15, close valve 16, monitor the ozone change at the outlet of the first reactor 2-1, and when the ozone concentration at the inlet / outlet of the first reactor 2-1 is the same, turn off the ozone generator.

[0180] (9) When the total hydrocarbon concentration exceeds 10 ppm, refer to steps 2-8, and switch valves 4-16 to allow the circulating gas to re-enter the first reactor 2-1, while the ozone enters the second reactor 2-2. The total hydrocarbon analyzer monitors the total hydrocarbon at the outlet of the first reactor 2-1, and the ozone analyzer monitors the ozone at the outlet of the second reactor 2-2.

[0181] (10) Referring to steps 2-9, isopentane degradation can be achieved while ensuring that the CO2 generated during the isopentane degradation process will not accumulate in the circulating gas.

[0182] (11) When the ozone concentration at the outlet of reactor 3 exceeds 10 ppm and all the material surfaces in the COx filter turn red, replace or regenerate the catalyst and adsorbent in reactor 3 and COx filter.

[0183] Note: In this embodiment, except for Figure 1 In addition to the indicated monitoring equipment, key parameters such as isopentane concentration, ozone concentration, COx concentration, and NOx concentration were measured at the inlet and outlet of each reactor. Detailed data, such as... Figure 4 As shown.

[0184] Example 4

[0185] Treatment of exhaust gas containing VOCs and oxygen-deficient (1% oxygen content).

[0186] The target gas to be treated is the organic waste gas generated during the process. The gas composition includes nitrogen (89%), carbon dioxide (10%), oxygen (1%), and ethylene (460-510 ppm), with a flow rate of 570 m³. 3 / h.

[0187] according to Figure 1 The main process parameters of the described waste gas treatment device are as follows: Reactor 1 adopts an array-distributed axial-cylinder plasma generator with an electrode gap of 5mm, a high-frequency AC power supply, and a discharge space of 1.2m. 3 The discharge area is filled with spherical barium titanate particles with a diameter of 1-2 mm; the ozone generator outputs an ozone concentration of 0-100% and an output gas volume of 0-10 m³ / s. 3 / h; The first reactor 2-1 and the second reactor 2-2 are designed identically, both employing arrayed axial-tube plasma generators with an electrode gap of 6mm, high-frequency AC power supplies, and a discharge space of 1.8m. 3 The discharge region is filled with spherical Ce with a diameter of 2-3 mm.0.6 Co 0.4 O2 / molecular sieve; reactor 3 is filled with 1m³ of O2 / molecular sieve. 3 MnO2 / activated carbon; no COx filter installed; no valves 8, 9, and 17 and their associated piping installed.

[0188] The operating procedure after the exhaust gas is introduced into the waste gas treatment device is as follows:

[0189] (1) Open valve 01, close valves 2 and 03, and short-circuit reactor 1;

[0190] (2) Open valves 4, 5, 10 and 11 to allow the exhaust gas to enter the first reactor 2-1 and the second reactor 2-2 respectively, and then enter reactor 3. The discharge voltage of the first reactor 2-1 and the second reactor 2-2 is set to 18kV.

[0191] (3) Open valves 6 and 7, turn on the ozone generator, and adjust the ozone concentration to 500 ppm and the gas flow rate to 4 m³ / h. 3 / h;

[0192] (4) Open valve 14, close valves 12 and 13, and monitor the total hydrocarbon changes at the outlets of the first reactor 2-1 and the second reactor 2-2;

[0193] (5) Close valves 15 and 16;

[0194] (6) When the total hydrocarbon concentration exceeds 10 ppm (assuming the emission standard concentration is 10 ppm), increase the ozone intake concentration or flow rate, or increase the discharge voltage of the first reactor 2-1 and the second reactor 2-2 until the value in the total hydrocarbon analyzer is lower than 10 ppm; if the total hydrocarbon concentration cannot be reduced to the emission standard, the device shall be shut down.

[0195] (7) When the ozone concentration exceeds 10 ppm, replace the catalyst in reactor 3.

[0196] Note: In this embodiment, except for Figure 1 In addition to the indicated monitoring equipment, key parameters such as ethylene concentration, ozone concentration, COx concentration, and NOx concentration were measured at the inlet and outlet of each reactor. Detailed data, such as... Figure 5 As shown.

[0197] Example 5

[0198] Treatment of exhaust gas containing VOCs and oxygen-deficient (4% oxygen content).

[0199] The target gas to be treated is the organic waste gas generated during the process. The gas composition includes nitrogen (84%), carbon dioxide (12%), oxygen (4%), and toluene (220-300 ppm), with a flow rate of 570 m³. 3 / h.

[0200] according to Figure 1 The main process parameters of the described waste gas treatment device are as follows: Reactor 1 adopts an array-distributed axial-cylinder plasma generator with an electrode gap of 5mm, a high-frequency AC power supply, and a discharge space of 1.2m. 3 The discharge area is filled with spherical barium titanate particles with a diameter of 1-2 mm; the ozone generator outputs an ozone concentration of 0-100% and an output gas volume of 0-10 m³ / s. 3 / h; The first reactor 2-1 and the second reactor 2-2 are designed identically, both employing arrayed axial-tube plasma generators with an electrode gap of 6mm, high-frequency AC power supplies, and a discharge space of 1.8m. 3 The discharge region is filled with spherical Ce with a diameter of 2-3 mm. 0.6 Co 0.4 O2 / molecular sieve; reactor 3 is filled with 1m³ of O2 / molecular sieve. 3 MnO2 / activated carbon; no COx filter installed; no valves 8, 9, and 17 and their associated piping installed.

[0201] The operating procedure after the exhaust gas is introduced into the waste gas treatment device is as follows:

[0202] (1) Open valve 2 and valve 03, close valve 01, so that the exhaust gas enters reactor 1 first. The discharge voltage of reactor 1 is set to 17kV.

[0203] (2) Open valves 4, 5, 10 and 11 to allow the exhaust gas to enter the first reactor 2-1 and the second reactor 2-2 respectively, and then enter reactor 3. The discharge voltage of the first reactor 2-1 and the second reactor 2-2 is set to 18kV.

[0204] (3) Open valves 6 and 7, turn on the ozone generator, and adjust the ozone concentration to 200 ppm and the gas flow rate to 2 m³ / h. 3 / h;

[0205] (4) Open valve 14, close valves 12 and 13, and monitor the total hydrocarbon changes at the outlets of the first reactor 2-1 and the second reactor 2-2;

[0206] (5) Close valves 15 and 16;

[0207] (6) When the total hydrocarbon concentration exceeds 10 ppm (assuming the emission standard concentration is 10 ppm), increase the ozone inlet concentration or flow rate, or increase the discharge voltage of reactor 1, first reactor 2-1 and second reactor 2-2 until the value in the total hydrocarbon analyzer is lower than 10 ppm; if the total hydrocarbon concentration cannot be reduced to the emission standard, the device shall be shut down.

[0208] (7) When the ozone concentration exceeds 10 ppm, replace the catalyst in reactor 3.

[0209] Note: In this embodiment, except for Figure 1 In addition to the indicated monitoring equipment, key parameters such as ethylene concentration, ozone concentration, COx concentration, and NOx concentration were measured at the inlet and outlet of each reactor. Detailed data, such as... Figure 6 As shown.

[0210] Example 6

[0211] Treatment of exhaust gas containing VOCs and oxygen-deficient (13% oxygen content) gases.

[0212] The target gas to be treated is the organic waste gas generated during the process. The gas composition includes nitrogen (87%), oxygen (13%), and ethanol (260-330 ppm), and the gas volume is 450 m³. 3 / h.

[0213] according to Figure 1 The main process parameters of the described waste gas treatment device are as follows: Reactor 1 adopts an array-distributed axial-cylinder plasma generator with an electrode gap of 5mm, a high-frequency AC power supply, and a discharge space of 1.2m. 3 The discharge area is filled with spherical barium titanate particles with a diameter of 1-2 mm; the ozone generator outputs an ozone concentration of 0-100% and an output gas volume of 0-10 m³ / s. 3 / h; The first reactor 2-1 and the second reactor 2-2 are designed identically, both employing arrayed axial-tube plasma generators with an electrode gap of 6mm, high-frequency AC power supplies, and a discharge space of 1.8m. 3 The discharge region is filled with spherical Ce with a diameter of 2-3 mm. 0.6 Co 0.4 O2 / molecular sieve; reactor 3 is filled with 1m³ of O2 / molecular sieve. 3 MnO2 / activated carbon; no COx filter installed; no valves 8, 9, and 17 and their associated piping installed.

[0214] The operating procedure after the exhaust gas is introduced into the waste gas treatment device is as follows:

[0215] (1) Open valve 2 and valve 03, close valve 01, so that the tail gas enters reactor 1 first. The discharge voltage of reactor 1 is set to 16kV.

[0216] (2) Open valves 4, 5, 10 and 11 to allow the exhaust gas to enter the first reactor 2-1 and the second reactor 2-2 respectively, and then enter reactor 3. The discharge voltage of the first reactor 2-1 and the second reactor 2-2 is set to 18kV.

[0217] (3) Close valves 6 and 7;

[0218] (4) Open valve 14, close valves 12 and 13, and monitor the total hydrocarbon changes at the outlets of the first reactor 2-1 and the second reactor 2-2;

[0219] (5) Close valves 15 and 16;

[0220] (6) When the total hydrocarbon concentration exceeds 10 ppm (assuming the emission standard concentration is 10 ppm), increase the discharge voltage of reactor 1, first reactor 2-1 and second reactor 2-2, or open valves 6 and 7, turn on the ozone generator, and adjust the ozone concentration to 400 ppm and the gas flow rate to 4 m³ / s. 3 The process continues until the total hydrocarbon concentration in the analyzer drops below 10 ppm; if the total hydrocarbon concentration cannot be reduced to the emission standard, the unit is shut down.

[0221] (7) When the ozone concentration exceeds 10 ppm, replace the catalyst in reactor 3.

[0222] Note: In this embodiment, except for Figure 1 In addition to the indicated monitoring equipment, key parameters such as ethylene concentration, ozone concentration, COx concentration, and NOx concentration were measured at the inlet and outlet of each reactor. Detailed data, such as... Figure 7 As shown.

[0223] 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 low-temperature plasma catalytic treatment system for organic waste gas, characterized in that, The system includes a first reaction unit, a second reaction unit, a third reaction unit, an ozone generator (18), and a COx filter (19). The first reaction unit is a plasma reactor connected to a high-voltage power supply. The second reaction unit includes two or more plasma reactors connected to a high-voltage power supply. Both the second reaction unit and the third reaction unit are reactors containing transition metal oxide catalysts. The gas supply source supplies the organic waste gas to be treated to the first reaction unit through a pipeline with valves, or supplies the organic waste gas to be treated to each reactor of the second reaction unit through a pipeline with valves. The outlet of the first reaction unit is connected to the inlet of each reactor in the second reaction unit via pipelines equipped with valves. The outlet of the ozone generator (18) is connected to the inlet of each reactor in the second reaction unit via pipelines with valves. The outlets of each reactor in the second reaction unit are connected to the inlet of the third reaction unit via pipelines with valves, so that the gases discharged from each reactor in the second reaction unit can enter the third reaction unit individually or in combination. The outlets of each reactor in the second reaction unit are connected to the inlet of the COx filter (19) via pipelines with valves, so that the gas discharged from each reactor in the second reaction unit can enter the COx filter (19) individually or in combination. The outlet of the third reaction unit is connected to the inlet of the COx filter (19) via a pipeline with a valve.

2. The system according to claim 1, characterized in that, The system also includes a total hydrocarbon analyzer (20) for monitoring the total hydrocarbon concentration of the gas discharged from the outlet of each reactor of the second reaction unit, or for monitoring the total hydrocarbon concentration in the gas after the gas discharged from the outlet of each reactor of the second reaction unit is combined.

3. The system according to claim 1 or 2, characterized in that, The system also includes a first ozone analyzer (21) for monitoring the ozone concentration of gases discharged from the outlets of the respective reactors of the second reaction unit.

4. The system according to claim 1 or 2, characterized in that, The system also includes a second ozone analyzer (22) for monitoring the ozone concentration of the gas discharged from the outlet of the third reaction unit.

5. A low-temperature plasma catalytic treatment method for organic waste gas, characterized in that, The method is implemented in the system according to any one of claims 1-4, the method comprising: (1) Determine the treatment requirements for organic waste gas, wherein the treatment requirements for organic waste gas include continued recycling after treatment or direct discharge after treatment; (2) Determine the oxygen content of the organic waste gas; (3) Depending on the treatment requirements of the organic waste gas and the different oxygen content, the organic waste gas is input into the system for treatment according to different operating schemes.

6. The method according to claim 5, characterized in that, When the treatment requirement for the organic waste gas is that the treated waste gas should be continuously recycled, and the oxygen content of the organic waste gas is ≤1%, (I) The organic waste gas in the gas supply source is supplied to the first reactor (2-1) in the second reaction unit for treatment, then processed through the COx filter (19), and then recycled back to the gas supply source for continued recycling. (II) When the total hydrocarbon concentration at the outlet of the first reactor (2-1) exceeds the emission standard, the organic waste gas from the gas supply source is supplied to the second reactor (2-2) in the second reaction unit for treatment; (III) Ozone is input into the first reactor (2-1) through the ozone generator (18), and the excess ozone discharged from the first reactor (2-1) is processed in the third reaction unit. When the ozone concentration at the outlet of the first reactor (2-1) is the same as the ozone concentration at the inlet, the input of ozone into the first reactor (2-1) is stopped. (IV) If the total hydrocarbon concentration at the outlet of the second reactor (2-2) exceeds the emission standard, refer to steps (I) to (III) to supply the organic waste gas from the gas supply source to the first reactor (2-1) or other reactors in the second reaction unit again, and input ozone into the second reactor (2-2) through the ozone generator (18); (V) Repeat steps (I) to (IV).

7. The method according to claim 5, characterized in that, When the treatment requirement for the organic waste gas is that the treated waste gas should be continuously recycled, and the oxygen content of the organic waste gas is greater than 1% and less than or equal to 10%, (I) The organic waste gas from the gas supply source is supplied to the first reaction unit for treatment; (II) The organic waste gas discharged from the first reaction unit is transported to the first reactor (2-1) in the second reaction unit for treatment, then processed through the COx filter (19), and then recycled back to the gas supply source for continued recycling. (III) When the total hydrocarbon concentration at the outlet of the first reactor (2-1) exceeds the emission standard, the organic waste gas discharged from the first reaction unit is transported to the second reactor (2-2) in the second reaction unit for treatment; (IV) Ozone is input into the first reactor (2-1) through the ozone generator (18), and the excess ozone discharged from the first reactor (2-1) is processed in the third reaction unit. When the ozone concentration at the outlet of the first reactor (2-1) is the same as the ozone concentration at the inlet, the input of ozone into the first reactor (2-1) is stopped. (V) If the total hydrocarbon concentration at the outlet of the second reactor (2-2) exceeds the emission standard, refer to steps (II) to (IV) to supply the organic waste gas discharged from the first reaction unit to the first reactor (2-1) or other reactors in the second reaction unit again, and input ozone into the second reactor (2-2) through the ozone generator (18); (VI) Repeat steps (II) to (V).

8. The method according to claim 5, characterized in that, When the treatment requirement for the organic waste gas is that the treated waste gas should be continuously recycled, and the oxygen content of the organic waste gas is greater than 10% and less than or equal to 20%, (I) The organic waste gas from the gas supply source is supplied to the first reaction unit for treatment; (II) The organic waste gas discharged from the first reaction unit is transported to the first reactor (2-1) in the second reaction unit for treatment, and then transported to the third reaction unit for treatment. It is then processed through the COx filter (19) and then recycled back to the gas supply source for further recycling. (III) When the total hydrocarbon concentration at the outlet of the first reactor (2-1) exceeds the emission standard, the organic waste gas discharged from the first reaction unit is transported to the second reactor (2-2) in the second reaction unit for treatment; (IV) Ozone is input into the first reactor (2-1) through the ozone generator (18), and the excess ozone discharged from the first reactor (2-1) is processed in the third reaction unit. When the ozone concentration at the outlet of the first reactor (2-1) is the same as the ozone concentration at the inlet, the input of ozone into the first reactor (2-1) is stopped. (V) If the total hydrocarbon concentration at the outlet of the second reactor (2-2) exceeds the emission standard, refer to steps (II) to (IV) to supply the organic waste gas discharged from the first reaction unit to the first reactor (2-1) or other reactors in the second reaction unit again, and input ozone into the second reactor (2-2) through the ozone generator (18); (VI) Repeat steps (II) to (V).

9. The method according to claim 5, characterized in that, When the treatment requirement for the organic waste gas is that it is directly discharged after treatment, and the oxygen content of the organic waste gas is ≤1%, (I) The organic waste gas from the gas supply source is supplied to all the reactors in the second reaction unit for treatment, and ozone is introduced into all the reactors in the second reaction unit through the ozone generator (18); (II) When the total hydrocarbon concentration of the mixed gas discharged from the second reaction unit exceeds the emission standard, increase the ozone intake concentration or flow rate, or increase the discharge voltage of each reactor in the second reaction unit until the total hydrocarbon concentration of the mixed gas is lower than the emission standard.

10. The method according to claim 5, characterized in that, When the treatment requirement for the organic waste gas is that it be directly discharged after treatment, and the oxygen content of the organic waste gas is greater than 1% and less than or equal to 10%, (I) The organic waste gas from the gas supply source is supplied to the first reaction unit for treatment; (II) The organic waste gas discharged from the first reaction unit is respectively transported to all reactors in the second reaction unit for treatment, and ozone is respectively input into all reactors in the second reaction unit through the ozone generator (18); (III) When the total hydrocarbon concentration of the mixed gas discharged from the second reaction unit exceeds the emission standard, increase the ozone intake concentration or flow rate, or increase the discharge voltage of each reactor in the second reaction unit until the total hydrocarbon concentration of the mixed gas is lower than the emission standard.

11. The method according to claim 5, characterized in that, When the treatment requirement for the organic waste gas is that it be directly discharged after treatment, and the oxygen content of the organic waste gas is greater than 10% and less than or equal to 20%, (I) The organic waste gas from the gas supply source is supplied to the first reaction unit for treatment; (II) The organic waste gas discharged from the first reaction unit is respectively transported to all reactors in the second reaction unit for treatment; (III) When the total hydrocarbon concentration of the mixed gas discharged from the second reaction unit exceeds the emission standard, increase the discharge voltage of each reactor in the second reaction unit, or input ozone into all reactors in the second reaction unit through the ozone generator (18) and adjust the ozone intake concentration or flow rate until the total hydrocarbon concentration of the mixed gas is lower than the emission standard.

12. The method according to any one of claims 5-11, characterized in that, The reactor of the first reaction unit is filled with ferroelectric material; The ferroelectric material is a natural crystal and / or a synthetic crystal, wherein the natural crystal is at least one of barium titanate, potassium dihydrogen phosphate and sodium nitrite, and the synthetic crystal is a crystal with further enhanced polarization under a high voltage electric field obtained by modifying the natural crystal.

13. The method according to any one of claims 5-11, characterized in that, The reactor of the second reaction unit is filled with a first transition metal oxide catalyst. In the first transition metal oxide catalyst, the active component is a transition metal oxide, wherein the transition metal is one or at least a combination of two of the following: Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu and Zn. The support is alumina, activated carbon, molecular sieve or MOFs.

14. The method according to any one of claims 5-11, characterized in that, The reactor of the third reaction unit is filled with a second transition metal oxide catalyst. In the second transition metal oxide catalyst, the active component is a transition metal oxide, wherein the transition metal is one or any combination of at least two of Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu and Zn, and the support is alumina, activated carbon, molecular sieve or MOFs.

Images