CN108543418B - A slot-type exhaust gas purification device that can be combined in multiple stages - Google Patents

Abstract

The invention relates to a slot-type exhaust gas purification device that can be combined in multiple stages. The air inlet and the air outlet are respectively provided, and the filter unit slot, the plasma catalytic reaction unit slot and the multifunctional catalyst unit slot matching the filter unit, the plasma catalytic reaction unit and the multifunctional catalyst unit are set on the top of the box. . Compared with the prior art, the invention adopts the slot type, which is convenient for loading and unloading, replacement and maintenance, high flexibility of device engineering operation, adjustable number of catalyst loading modules, free series-parallel multi-level combination of the box body, and strong adaptability. The device of the invention can realize the efficient degradation of waste gas containing VOCs and odor, and can also treat the residual CO and O3 to reach the standard discharge.

Description

A slot-type exhaust gas purification device that can be combined in multiple stages

technical field

The invention relates to the technical field of exhaust gas purification, in particular to a slot-type exhaust gas purification device that can be combined in multiple stages.

Background technique

At present, the emission of various toxic and harmful gases has caused serious environmental pollution, and the total amount of emissions is huge and growing rapidly. Low-concentration harmful gaseous pollutants (such as VOCs, H ₂ S, NO _x , NH ₃ , etc.) are widely produced in the processes of transportation, industrial production, energy conversion, daily life, etc. Cause chronic damage or even poisoning life-threatening. In recent years, major national environmental protection policies have been introduced one after another, and the control of waste gas pollution such as VOCs and odors has entered the main battlefield of environmental protection work.

At present, waste gas treatment technologies such as VOCs and odors are mainly divided into two categories. One is recovery technology, which mainly uses various physical methods to absorb, filter, and separate the discharged waste gas, and then recycle it for recycling, including adsorption, condensation. , membrane separation, absorption and other technologies. The other type is decomposition technology, mainly chemical treatment and biological treatment methods, which decompose and convert the emitted VOCs or odors into other non-toxic, harmless and odorless substances, including thermal combustion, catalytic combustion, plasma, chemical absorption. , UV light (catalytic) oxidation, biological treatment and other technologies. Based on strict emission policies, it is the trend of industry governance to encourage the use of waste gas cleaning technology to avoid secondary pollution. However, the concentration of waste gas treatment industries such as VOCs and odor is low, and the contradiction between the continuous improvement of environmental protection requirements and the relative insufficiency of treatment capacity is becoming more and more prominent. Efficient technology and low-price competition are not conducive to the healthy and sustainable development of the entire VOCs, odor and other waste gas treatment industries.

For small and medium-sized enterprises, the development of low-cost, high-efficiency and energy-saving VOCs, odor and other waste gas treatment technologies, as well as complete sets of combined processes and equipment, is a challenge and opportunity for the waste gas treatment industry. Effective Ways. Destructive VOCs, odor and other waste gas treatment technologies are relatively cleaner, more thorough, and more environmentally friendly. Among them, catalytic combustion technology has high treatment efficiency, but the use of precious metal catalysts is expensive and significantly increases treatment costs. The temperature and energy consumption are relatively large, and it is not suitable for the treatment of waste gas in intermittent working conditions. The emerging plasma method has become a research hotspot due to its advantages of rapid reaction, wide application range and mild reaction conditions. However, the plasma treatment of VOCs and odorous waste gas also has some problems: 1. The short residence time leads to low degradation rate of VOCs such as benzene series; 2. A certain concentration of O ₃ will be generated in the exhaust gas; 3. The selectivity is not high, Hazardous by-products are easier to generate. The effective combination of plasma and catalyst can solve the above problems to a certain extent.

Delagrange et al. (S.Delagrange, et al. Applied Catalysis B. 2006:68:92-98) combined dielectric barrier discharge with MnO ₂ /γ-Al ₂ O ₃ catalyst to treat toluene, and found that the conversion of toluene after the combination of the two was Compared with the single discharge, the catalyst also effectively suppressed the generation of _O3 , but the proportion of CO in the product _COx still exceeded 43%. Chinese patent CN 105797579A discloses a process for plasma synergistic mesoporous catalytic treatment of VOCs. The process combines mesoporous catalyst adsorption, catalytic oxidation and plasma enhancement to treat volatile organic waste gas, which consumes energy. Low, simple equipment, low cost, but the processing airspeed (5000h ^-1 ) is small. Chinese patent CN 105749744A discloses a filled low-temperature plasma synergistic adsorption catalytic VOCs purification device, which integrates low-temperature plasma technology, adsorption technology and catalytic technology, has the ability to efficiently decompose pollutant molecules, and has low processing energy consumption. However, its fixed one-stage structure is inflexible and cannot adapt to various working conditions, and the filled activated carbon adsorbent needs to be replaced regularly.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a slot-type exhaust gas purification device with flexible structure that can be combined in multiple stages in order to overcome the above-mentioned defects of the prior art.

The object of the present invention can be achieved by the following technical solutions: a slot-type exhaust gas purification device that can be combined in multiple stages, the device comprises a box body and a filter unit, a plasma catalytic reaction unit and a multi-stage filtration unit which are sequentially inserted in the box body. A functional catalyst unit, the two ends of the box body are respectively provided with an air inlet and an air outlet, and a filter unit slot, plasma Reaction unit slot and multifunctional catalyst unit slot. When the device is running, exhaust gas such as VOCs and odors enters the device through the air inlet through the rear fan, and then enters the plasma catalytic reaction unit after being filtered by the filter unit, where high-voltage ionization, oxidative degradation and synergistic treatment of catalysts are performed. The treated gas is further catalyzed and oxidized by the multi-functional catalyst unit, and finally the exhaust gas such as VOCs and odor is completely converted into odorless gas such as CO ₂ and H ₂ O, and then it is drawn out by the fan. Since the filter unit, the plasma catalytic reaction unit and the multifunctional catalyst unit are installed in the box in the form of plug-in boards and slots, the device is convenient for disassembly, assembly and replacement, and has higher flexibility.

The filter unit includes a filter cover plate arranged horizontally at the top and a mesh insert plate arranged perpendicular to the filter cover plate.

The aperture of the mesh insert is 0.5-5 mm.

The plasma catalytic reaction unit includes a reaction cover plate arranged horizontally at the top and a reaction insert plate arranged perpendicular to the reaction cover plate, and a plurality of plasma reaction plates arranged in parallel along the airflow direction are fixed in the reaction insert plate. The plasma reactor is filled with the first catalyst. The effective combination of plasma treatment and catalyst treatment can quickly remove most of the harmful substances in the exhaust gas.

The plasma reactor is a double-dielectric barrier discharge reactor, and the first catalyst is packed in the afterglow zone immediately after the discharge area. The high concentration of VOCs is prone to safety accidents.

The first catalyst is a spherical supported first catalyst, and the carrier of the first catalyst is selected from Al ₂ O ₃ , SiO ₂ , TiO ₂ , SBA-15, ZSM-5, 13X, 10X, 4A, 5A Or one or more of activated carbon, the active components of the first catalyst are selected from CrO _x , MnO _x , FeO _x , CoO _x , NiO, CuO, ZnO, CeO ₂ , La ₂ O ₃ , MoO _x , One or more of SnO ₂ or ZrO ₂ , wherein the weight percentage of the active component is 1% to 10%.

The number of the plasma reactors is 3 to 10 pieces.

The multifunctional catalyst unit includes a plurality of subunits arranged in parallel along the airflow direction, each subunit includes a catalyst cover plate arranged horizontally at the top and a catalyst insert plate arranged perpendicular to the catalyst cover plate, and each catalyst insert plate is filled with second catalyst. The number of catalyst inserts can be flexibly selected and inserted according to the severity of the actual working conditions, and the slot of the unused segment is sealed by the cover plate, which overcomes the problem that the fixed catalyst loading cannot adapt to various working conditions.

The second catalyst is a honeycomb monolithic catalyst, the matrix of the second catalyst is a honeycomb ceramic carrier, and the coating of the second catalyst is calcined hydrotalcite-like Mg(M)(Al)O, wherein M is Cr , one or more of Mn, Fe, Co, Cu, Zn, Ce, Mo, Sn or Zr; the active components of the second catalyst are CrO _x , MnO _x , FeO _x , CoO _x , NiO, CuO, _One or more of ZnO or CeO2. The calcined hydrotalcite-like has a high specific surface area, which is conducive to the high dispersion of active components and inhibits the agglomeration of active components. The introduction of elements such as Cr, Ce, Mo, Zr can improve the oxygen storage capacity of the catalyst, which is beneficial Further oxidative decomposition of pollutant molecules.

The air inlet and the air outlet are provided with sealing flanges and are connected with the exhaust gas pipeline. As each independent small unit, the box body can be freely combined in series or in parallel to form a larger exhaust gas treatment unit to adapt to different working conditions.

Compared with the prior art, the beneficial effects of the present invention are embodied in the following aspects:

(1) In the plasma catalytic reaction unit of the device, the catalyst is placed in the afterglow area of the plasma discharge, which overcomes the problem that the catalyst is placed inside the discharge area of the reactor due to the high concentration of VOCs during the plasma-catalyst coordination process. .

(2) In the multifunctional catalyst unit of the device of the present invention, the catalyst is filled in a monolithic honeycomb ceramic monolithic catalyst module, which overcomes the problem of large wind resistance when the granular catalyst is filled, and the catalyst can simultaneously treat VOCs, CO and O3, and realize multifunctional purification. effect. The coating (second carrier) of the monolithic catalyst adopts calcined hydrotalcite-like material, which improves the dispersion of active components, inhibits agglomeration, prolongs the service life of the catalyst, increases the oxygen storage capacity, and reduces the emission of by-products .

(3) The filter unit, the plasma catalytic reaction unit and the multifunctional catalyst unit in the device of the present invention are all arranged in a slot type, which is convenient for loading and unloading, replacement and maintenance. The multi-functional catalyst unit is divided into three sections, and the number of modules to be inserted into the catalyst can be flexibly selected according to the severity of the actual working conditions. The slot of the section is not used for cover sealing, which overcomes the problem that the fixed catalyst loading cannot adapt to various working conditions.

(4) The device of the present invention has high engineering operation flexibility. The air inlet end and the air outlet end of the box body can be connected by flange sealing. As each independent small unit, the box body can be freely combined in series or in parallel to form a more Large exhaust gas treatment unit to adapt to different working conditions.

Description of drawings

FIG. 1 is a schematic diagram of the three-dimensional structure of the device of the present invention.

FIG. 2 is a schematic sectional view of the device of the present invention.

Among them, 1 is the box, 2 is the filter unit slot, 3 is the plasma catalytic reaction unit slot, 4 is the multi-functional catalyst unit slot, 5 and 6 are the sealing flanges, 7 is the air inlet, and 8 is the outlet. Air port, 9 is a filter unit, 91 is a filter cover, 92 is a filter insert, 10 is a plasma catalytic reaction unit, 101 is a reaction cover, 102 is a reaction insert, 103 is a dual dielectric barrier discharge reactor, 104 is In the discharge area, 105 is the first catalyst, 11 is the multifunctional catalyst unit, 111 is the catalyst cover plate, 112 is the catalyst insert plate, and 113 is the second catalyst.

Detailed ways

The embodiments of the present invention are described in detail below. This embodiment is implemented on the premise of the technical solution of the present invention, and provides a detailed implementation manner and a specific operation process, but the protection scope of the present invention is not limited to the following implementation. example.

Example 1

A slot-type exhaust gas purification device that can be combined in multiple stages, its structure is shown in Figures 1 and 2, including a box 1 and a filter unit 9, a plasma catalytic reaction unit 10 and a multifunctional catalyst unit 11, wherein the box The body 1 is provided with a filter unit slot 2, a plasma catalytic reaction unit slot 3, and a multifunctional catalyst unit slot 4 for inserting the filter unit 9, the plasma catalytic reaction unit 10 and the multifunctional catalyst unit 11, respectively. Both ends of the body are provided with an air inlet 7 and an air outlet 8, and a sealing flange 5 is arranged at the air inlet 7, and a sealing flange 6 is arranged at the air outlet 8.

The filter unit 9 includes a filter cover plate 91 arranged horizontally at the top and a mesh insert plate 92 arranged perpendicular to the filter cover plate 91 .

The plasma catalytic reaction unit 10 includes a reaction cover plate 101 arranged horizontally at the top and a reaction insert plate 102 arranged perpendicular to the reaction cover plate 101. The reaction insert plate 102 is fixedly provided with a plurality of dual dielectric barriers arranged in parallel along the airflow direction The discharge reactor 103 and the double dielectric barrier discharge reactor 103 are filled with the first catalyst 105, and the first catalyst 105 is filled in the afterglow area immediately after the discharge area 104.

The multifunctional catalyst unit 11 includes three sub-units arranged in parallel along the airflow direction, and each sub-unit includes a catalyst cover plate 111 arranged horizontally at the top and a catalyst insert plate 112 arranged perpendicular to the catalyst cover plate 111. The second catalyst 113 is charged.

The VOCs waste gas to be treated enters the device from the air inlet 7, and is first filtered and pretreated by the filter unit 9. The treated waste gas enters the plasma catalytic reaction unit 10, and the VOCs are oxidized and degraded by the plasma in the discharge area 103 without being degraded. The VOCs and the small molecules with broken bonds but not completely degraded further undergo oxidation reaction with the oxygen-containing active radicals generated by the plasma discharge trapped by the first catalyst 105, and then the gas enters the multifunctional catalyst module 11, and the residual CO is catalyzed. The effect is converted into CO ₂ , O ₃ is completely decomposed, and the generated oxygen radicals again have a catalytic oxidation reaction with the VOCs that have not been degraded, and the products CO ₂ and H ₂ O are drawn out by the fan.

The above device was used for the treatment of waste gas containing toluene, the flow rate of waste gas was 0.27 m ³ /h, and the initial concentration of toluene was 500 mg/m ³ . MnO _x -CeO ₂ /Al ₂ O ₃ -ZSM-5 was used as the catalyst loaded in the afterglow zone, and a CuO-MnO _x /Mg(Ce)(Al)O/CC monolithic catalyst module was inserted into the multifunctional catalyst unit. The device treated toluene waste gas for 48 hours with stable effect, toluene degradation rate reached 95%, CO ₂ selectivity was over 90%, the outlet CO concentration was lower than 350 mg/m ³ , and O ₃ was not detected.

Example 2

The same device as in the embodiment was used for the treatment of waste gas containing n-heptane, the flow rate of waste gas was 0.27 m ³ /h, and the initial concentration of n-heptane was 500-1000 mg/m ³ . MnO _x -FeO _x /Al ₂ O ₃ was used as the catalyst loaded in the afterglow area, and a MnO _x -CeO ₂ /Mg(Zr)(Al)O/CC monolithic catalyst module was inserted into the multifunctional catalyst unit. The device treated n-heptane waste gas for 48 hours with stable effect. The n-heptane degradation rate reached 98%, the CO ₂ selectivity was over 95%, the outlet CO concentration was lower than 175 mg/m ³ , and O ₃ was not detected.

Example 3

The same device as in the embodiment was used for the treatment of waste gas containing ethyl acetate, the flow rate of waste gas was 0.27 m ³ /h, and the initial concentration of ethyl acetate was 500-1000 mg/m ³ . MnO _x -CeO ₂ /AC was used as the catalyst loaded in the afterglow area, and a multifunctional catalyst unit was inserted into a MnO _x -CoO _x /Mg(Cr)(Al)O/CC monolithic catalyst module. The device treated ethyl acetate waste gas for 48 hours with stable effect, ethyl acetate degradation rate reached 96%, CO ₂ selectivity exceeded 95%, outlet CO concentration was lower than 20 mg/m ³ , and O ₃ was not detected.

Example 4

The same device as in the embodiment was used for the treatment of acetic acid-containing waste gas, the waste gas flow rate was 0.27 m ³ /h, and the initial concentration of acetic acid was 300-600 mg/m ³ . _MnOx - _FeOx /ZSM-5 was used as the catalyst loaded in the afterglow zone, and a CuO- _FeOx /Mg(Fe)(Al)O/CC monolithic catalyst module was inserted into the multifunctional catalyst unit. The device treated acetic acid waste gas for 48 hours, and the effect was stable. The degradation rate of acetic acid reached 97%, the selectivity of CO ₂ exceeded 96%, the outlet CO concentration was lower than 12 mg/m ³ , and O ₃ was not detected.

Example 5

The same device as in the example was used to treat the mixed waste gas containing n-heptane and ethyl acetate, the waste gas flow rate was 0.25 m ³ /h, and the total concentration of VOCs was 300 mg/m ³ . CuO-MnO _x -FeO _x /Al ₂ O ₃ -ZSM-5 is used as the catalyst loaded in the afterglow zone. The space velocity of the plasma catalytic reaction is about 15000h ^-1 . The multi-functional catalyst unit is not inserted into the integrated catalyst module, and the outlet exhaust gas is detected , the total concentration of VOCs is lower than 15mg/m ³ , the concentration of CO is lower than 15mg/m ³ , and O ₃ is not detected.

Example 6

^The same device as in the embodiment was used to treat the odorous and odorous waste gas containing H ₂ ^S , NH ₃ and organic acids in a domestic waste plant. Device configuration: The catalyst loaded in the afterglow area is CuO-MnO _x -FeO _x /AC, and a CuO-MnO _x -CoO _x /Mg(Zn)(Ce)(Al)O/CC monolithic catalyst is inserted into the plasma catalytic reaction unit module. The odor and odor outlet detection concentration is lower than 5mg/m ³ .

Example 7

The same device as in the example was used to carry out anti-corrosion painting on the inner surface of an oil pipeline. The exhaust gas contained VOCs such as benzene, toluene, and xylene, and the exhaust gas air volume was 800 m ³ /h. Device configuration: The catalyst loaded in the afterglow area is CuO-MnO _x -FeO _x /ZSM-5, and two CuO-MnO _x /Mg(Ce)(Al)O/CC monolithic catalyst modules are inserted into the plasma catalytic reaction unit. The outlet concentration of VOCs was detected to be lower than 6mg/m ³ .

Example 8

The same device as in the example was used to collect and treat waste gas containing methanol, xylene, acetic ^acid and other odors at the product outlet ^of a glove production workshop. Device configuration: The catalyst loaded in the afterglow area is CuO-MnO _x -FeO _x /AC-ZSM-5, and the plasma catalytic reaction unit is inserted into three pieces of CuO-MnO _x -CoO _x /Mg(Ce)(Zr)(Al)O /CC monolithic catalyst module. The odor removal rate of exhaust gas is over 95%, the employees' sense of smell has no odor, and the outlet ozone concentration reaches the standard.

Example 9

The same device as in the embodiment was used to purify the waste gas containing acetic acid and alcohols in a sewage pool, and the exhaust gas air volume was 1000 m ³ /h. Device configuration: The catalyst loaded in the afterglow area is CuO-MnO _x -FeO _x /AC-Al ₂ O ₃ -ZSM-5, and three pieces of CuO-MnO _x -CoO _x /Mg(Ce)(Zr )(Al)O/CC monolithic catalyst module. The removal rate of waste gas odor is more than 95%, and the customer's sense of smell has no peculiar smell of waste gas.

Claims (6)

1. A slot type waste gas purifying device capable of being combined in multiple stages is characterized by comprising a box body, a filtering unit, a plasma catalytic reaction unit and a multifunctional catalyst unit, wherein the filtering unit, the plasma catalytic reaction unit and the multifunctional catalyst unit are sequentially inserted into the box body;

the plasma catalytic reaction unit comprises a reaction cover plate and a reaction plug plate, wherein the top of the reaction cover plate is horizontally arranged, the reaction plug plate is vertical to the reaction cover plate, a plurality of plasma reactors which are arranged in parallel along the airflow direction are fixedly arranged in the reaction plug plate, and a first catalyst is filled in each plasma reactor;

the plasma reactor is a double-medium barrier discharge reactor, and the first catalyst is filled in an afterglow area next to the rear end of a discharge area;

the multifunctional catalyst unit comprises a plurality of subunits which are arranged in parallel along the airflow direction, each subunit comprises a catalyst cover plate and a catalyst inserting plate, the top of each catalyst cover plate is horizontally arranged, the catalyst inserting plate is perpendicular to the catalyst cover plate, and a second catalyst is filled in each catalyst inserting plate;

the second catalyst is a honeycomb type monolithic catalyst, the substrate of the second catalyst is a honeycomb ceramic carrier, and the coating of the second catalyst is calcined hydrotalcite-like Mg (M) (Al) O, wherein M is one or more of Cr, Mn, Fe, Co, Cu, Zn, Ce, Mo, Sn or Zr; the active component of the second catalyst is CrO_x、MnO_x、FeO_x、CoO_xNiO, CuO, ZnO or CeO₂One or more of (a).

2. The multi-stage combinable slot-in type exhaust gas purifying device as claimed in claim 1, wherein the filtering unit comprises a filtering cover plate horizontally arranged at the top and a mesh insert plate vertically arranged with the filtering cover plate.

3. The multi-stage combined slot-in type exhaust gas purification device as claimed in claim 2, wherein the mesh-like insertion plate has a pore size of 0.5-5 mm.

4. The multi-stage combinable slot-in type exhaust gas purifying device according to claim 1, wherein the first catalyst is a ball-type supported first catalyst, and a carrier of the first catalyst is selected from Al₂O₃、SiO₂、TiO₂、SBA-15、ZSM-5、13X、10One or more of X, 4A, 5A or activated carbon, and the active component of the first catalyst is selected from CrO_x、MnO_x、FeO_x、CoO_x、NiO、CuO、ZnO、CeO₂、La₂O₃、MoO_x、SnO₂Or ZrO₂Wherein, the weight percentage of the active component is 1 to 10 percent.

5. The multi-stage combined slot-in type exhaust gas purifying device according to claim 1, wherein the number of the plasma reactors is 3 to 10.

6. The multi-stage combinable slot-in type apparatus for purifying exhaust gas according to claim 1, wherein the inlet and outlet are provided with sealing flanges and connected to an exhaust gas pipe.

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