Waste gas treatment device and method

Abstract

The invention discloses a waste gas treatment device and method, and relates to the technical field of waste gas purification. The waste gas treatment device comprises a packaging shell, a SiC honeycomb ceramic carrier arranged in the packaging shell, a catalyst arranged on the SiC honeycomb ceramic carrier and aiming at target waste gas, pressing plates arranged at the two ends of the packaging shell and used for pressing the SiC honeycomb ceramic carrier, and an insulating mechanism arranged on the periphery of the SiC honeycomb ceramic carrier, the two ends of the SiC honeycomb ceramic carrier are connected with an external power source, it is guaranteed that the SiC honeycomb ceramic carrier is rapidly heated to the target temperature, the pressing plates located at the two ends of the packaging shell are provided with gas channels, waste gas is rapidly catalyzed and decomposed, the waste gas treatment efficiency can be guaranteed, and the waste gas treatment energy utilization efficiency can be improved.

Description

Technical Field

[0001] This invention relates to the field of waste gas purification technology, specifically to a waste gas treatment device and method. Background Technology

[0002] With increasingly stringent environmental protection requirements, the need for treatment of industrial and domestic waste gases, such as volatile organic compounds (VOCs), is becoming more urgent. Currently, mainstream treatment technologies include adsorption (such as activated carbon) and combustion (direct combustion, catalytic combustion). However, these technologies suffer from common contradictions in application. For example, efficient waste gas treatment at high temperatures using external heat sources often comes with high energy consumption, while low-energy adsorption technologies may face frequent catalyst replacements and secondary pollution problems after adsorption saturation.

[0003] Especially for decentralized and intermittent pollution sources, such as restaurant fumes, small workshops, and scattered emissions from specific industrial processes, existing technologies are overkill, neither economical nor easy to deploy effectively. The industry has long urgently needed a new waste gas treatment technology that can achieve rapid response, high-efficiency purification, energy saving, low consumption, and easy modular integration.

[0004] Existing technologies mainly fall into the following categories, each with its own obvious limitations: 1. Adsorption recovery / purification technology (such as activated carbon) Technical description: This method utilizes porous materials such as activated carbon to adsorb pollutants in waste gas. Once saturated, the materials need to be replaced or desorbed and regenerated.

[0005] shortcoming: Non-destructive treatment: This only involves the transfer of pollutants, which will generate hazardous waste after saturation, posing a risk of secondary pollution.

[0006] Limited applicability: It is ineffective in treating high-concentration, high-temperature, and high-humidity waste gases, and is not suitable for treating inorganic gases such as ammonia.

[0007] High operating costs: Frequent replacement of adsorbents is required, resulting in high long-term operating and maintenance costs.

[0008] 2. Traditional Catalytic Combustion (RCO) Technology Technical Description: This method utilizes a catalyst to oxidize VOCs at a relatively low ignition temperature. Typically, the exhaust gas or catalyst bed needs to be preheated to the reaction temperature using an external heater.

[0009] shortcoming: It starts up extremely slowly: the preheating process often takes more than 30 minutes, making it unable to handle immediate emissions.

[0010] High heat loss: Heat exchange is achieved through hot air convection, resulting in low energy utilization efficiency.

[0011] Large equipment size: Low-concentration waste gas requires the use of activated carbon, zeolite, etc. for enrichment, and also requires a complex preheating and heat exchange system, which is difficult to miniaturize.

[0012] Therefore, it is necessary to develop and design waste gas treatment devices and methods. Improving waste gas treatment efficiency while ensuring the destruction of waste gas is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0013] To address the aforementioned problems, this invention provides a waste gas treatment device and method that improves waste gas treatment efficiency while ensuring the destruction of waste gas.

[0014] To achieve the above objectives, the present invention provides the following solution: An exhaust gas treatment device includes an encapsulation shell (7), a SiC honeycomb ceramic carrier (5) disposed inside the encapsulation shell (7), and a catalyst for the target exhaust gas disposed on the SiC honeycomb ceramic carrier (5). Both ends of the SiC honeycomb ceramic carrier (5) are connected to an external power source, and both ends of the encapsulation shell (7) are provided with gas channels.

[0015] Preferably, it further includes pressure plates (1) disposed at both ends of the encapsulation shell (7) for pressing the SiC honeycomb ceramic carrier (5), and an insulation mechanism disposed on the outer periphery of the SiC honeycomb ceramic carrier (5), wherein the gas channel is disposed on the pressure plate (1).

[0016] Preferably, both ends of the SiC cellular ceramic carrier are connected to the external power source through perforated plates.

[0017] Preferably, an elastic contact mesh is provided between the perforated plate and the SiC honeycomb ceramic carrier.

[0018] Preferably, a wire outlet is provided on the perforated plate at one end, and the wire outlet is used for the wires of the other end of the perforated plate to pass through and connect to the external power source.

[0019] Preferably, the insulation mechanism includes an insulating liner disposed between the SiC cellular ceramic carrier and the encapsulation shell, and an insulating gasket disposed between the pressure plate and the perforated plate.

[0020] Preferably, the insulating liner is made of mica, refractory brick, or glass fiber.

[0021] Preferably, the insulating liner has a mounting groove on the side near the SiC honeycomb ceramic carrier, and a temperature sensor is installed in the mounting groove.

[0022] Preferably, the SiC honeycomb ceramic carrier has a honeycomb three-dimensional structure.

[0023] Preferably, the active component of the catalyst is a composite of one or more components selected from platinum, palladium, or copper.

[0024] This invention also discloses a waste gas treatment method, which utilizes the waste gas treatment device described above, characterized by mainly including the following steps: Connect the SiC honeycomb ceramic support to an external power source to bring the SiC honeycomb ceramic support to the predetermined catalyst reaction temperature. The exhaust gas enters from one end of the gas channel, is decomposed by the SiC honeycomb ceramic carrier, and is discharged from the other end of the gas channel.

[0025] The present invention achieves the following technical effects compared to the prior art: By placing a SiC honeycomb ceramic carrier inside the encapsulation shell and placing a catalyst on the SiC honeycomb ceramic carrier, when waste gas needs to be treated, an external power source is used to energize the SiC honeycomb ceramic carrier. The current flows through the SiC honeycomb ceramic carrier, and a large amount of Joule heat is generated through resistance, causing the SiC honeycomb ceramic carrier to heat up rapidly to the predetermined catalyst reaction temperature. Utilizing its own honeycomb structure, the inner walls of countless parallel channels form a huge geometric surface area, which enables the waste gas to be rapidly catalytically decomposed. This not only ensures the destruction of waste gas, but also improves the waste gas treatment efficiency. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Appendix Figure 1 This is a schematic diagram of the overall structure of the waste gas treatment device disclosed in this invention; Appendix Figure 2 This is an exploded view of the overall structure of the waste gas treatment device disclosed in this invention. Appendix Figure 3 This is a schematic diagram of the sensor installation structure of the waste gas treatment device disclosed in this invention; The components are: 1. Pressure plate; 2. Insulating gasket; 3. Perforated plate; 4. Elastic contact wire; 5. SiC honeycomb ceramic carrier; 6. Insulating liner; 7. Encapsulation shell; 8. Temperature sensor; 9. Pressure plate mounting hole; 10. Outlet; 11. Electrode mounting bolt. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] The purpose of this invention is to provide a waste gas treatment device and method that can not only ensure the treatment efficiency of waste gas, but also improve the energy utilization efficiency of waste gas treatment.

[0030] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] refer to Figures 1-2 The waste gas treatment device disclosed in this embodiment of the invention includes at least: a housing 7, which has an open structure at both ends, and a SiC honeycomb ceramic carrier 5 is housed inside the housing 7. A catalyst for the target waste gas is disposed on the SiC honeycomb ceramic carrier 5 (for example, if the target waste gas is volatile organic compounds, the active component of the catalyst is platinum or palladium; if the target waste gas is ammonia compounds, the active component of the catalyst is platinum or copper). By placing the SiC honeycomb ceramic carrier 5 inside the housing 7 and placing the catalyst on the SiC honeycomb ceramic carrier 5, when waste gas needs to be treated, the SiC honeycomb ceramic carrier 5 is energized by an external power source. The current flows through the SiC honeycomb ceramic carrier 5, and a large amount of Joule heat is generated through resistance, causing the SiC honeycomb ceramic carrier 5 to heat up rapidly to the predetermined catalyst reaction temperature. Utilizing its own honeycomb structure, the inner walls of countless parallel channels form a huge geometric surface area, allowing the waste gas to be rapidly catalytically decomposed. This not only ensures the destruction of waste gas but also improves the waste gas treatment efficiency.

[0032] It should be noted that the encapsulation shell 7 is made of insulating material to prevent the encapsulation shell 7 from conducting electricity with the SiC honeycomb ceramic carrier 5.

[0033] refer to Figures 1-2 In one embodiment, the two ends of the encapsulation shell 7 are provided with pressure plates 1 for pressing the two ends of the SiC honeycomb ceramic carrier 5. The outer periphery of the SiC honeycomb ceramic carrier 5 is provided with an insulating mechanism to prevent the pressure plates 1 and the encapsulation shell 7 from conducting electricity with the SiC honeycomb ceramic carrier 5. The two ends of the SiC honeycomb ceramic carrier 5 are connected to an external power source. The pressure plates 1 located at both ends of the encapsulation shell 7 are provided with gas channels to form an air inlet and an air outlet at the two ends of the encapsulation shell 7, respectively.

[0034] It should be noted that when the insulating liner 6 is provided, the encapsulation shell 7 is made of corrosion-resistant materials such as 304 stainless steel, providing structural support and an airtight environment. The encapsulation shell 7 is provided with pressure plate mounting holes 9 for mounting the pressure plate 1.

[0035] The catalyst is coated onto the SiC honeycomb ceramic carrier 5 using a coating machine, and then transferred into a muffle furnace and calcined at 550°C for 4 hours to set the catalyst on the SiC honeycomb ceramic carrier 5, which is made of silicon carbide material.

[0036] refer to Figures 1-2 In one embodiment, the two ends of the SiC honeycomb ceramic carrier 5 are connected to an external power source through a perforated plate 3. The perforated plate 3 is provided with multiple through holes and serves as both a conductive electrode and a uniform air distribution device.

[0037] It should be noted that the orifice plate 3 is a stainless steel orifice plate 3, and electrodes are mounted on the orifice plate 3 by electrode mounting bolts 11.

[0038] refer to Figures 1-2 In one implementation, an elastic contact mesh 4 is provided between the perforated plate 3 and the SiC honeycomb ceramic carrier 5. The elastic contact mesh 4 is a stainless steel filter mesh with elasticity to compensate for the unevenness of the contact surface between the perforated plate 3 and the SiC honeycomb ceramic carrier 5. The elasticity can ensure uniform current, stable conduction and no obstruction of gas flow.

[0039] refer to Figures 1-2 As one implementation method, a wire outlet is provided on the orifice plate 3 at one end, which is used for the wires of the other end of the orifice plate 3 to pass through and connect to an external power source.

[0040] refer to Figure 1 As a preferred embodiment, the insulation mechanism includes an insulating liner 6 and an insulating gasket 2 disposed between the SiC honeycomb ceramic carrier 5 and the encapsulation shell 7. The insulating liner 6 is used for electrical isolation and heat preservation. The insulating gasket 2 is disposed between the pressure plate 1 and the perforated plate 3. One end of the pressure plate 1 is pressed against the perforated plate 3 by the insulating gasket 2, and the other end is connected and fixed to the encapsulation shell 7. The insulating gasket 2 is used to achieve insulation between the pressure plate 1 and the perforated plate 3. This "external locking and internal pressing" structure achieves both mechanical fixing and high-voltage electrical insulation, ensuring that while the component is pressed, the current is limited to a set circuit (electrode -> perforated plate 3 -> elastic contact network 4 -> SiC honeycomb ceramic carrier 5 -> elastic contact network 4 -> perforated plate 3 -> electrode). The fixing bolt passes through the pressure plate mounting hole 9 of the encapsulation shell 7 and is screwed into the nut welded to the vertical arm of the pressure plate 1 to complete the final encapsulation.

[0041] refer to Figures 1-2As a preferred method, the insulating liner 6 is made of mica, refractory brick or glass fiber, which can not only achieve the effect of insulation, but also withstand high temperature.

[0042] refer to Figure 3 As one implementation method, the insulating liner 6 has an installation groove on the side near the SiC honeycomb ceramic carrier 5. A temperature sensor 8 (such as a K-type thermocouple) is installed in the installation groove to monitor the temperature of the SiC honeycomb ceramic carrier 5 in real time. The signal from the temperature sensor 8 is connected to the intelligent controller. The controller adjusts the output power of the external communicable power supply (such as a DC power supply supporting the 485 protocol) in real time according to the difference between the set temperature and the measured temperature, so as to achieve precise closed-loop control of the temperature of the catalytic unit and ensure that it is stable in the optimal temperature window required for the catalytic reaction.

[0043] refer to Figures 1-2 As one implementation method, the SiC honeycomb ceramic carrier 5 has a honeycomb three-dimensional structure, that is, the inner wall of countless parallel channels forms a huge geometric surface area, which provides sufficient contact area for subsequent coating of catalyst and contact reaction of waste gas, and can realize rapid heating of SiC honeycomb ceramic carrier 5.

[0044] It should be noted that the SiC honeycomb ceramic carrier 5 is a closed plate in the circumference, and gas channels are formed at both ends that penetrate the SiC honeycomb ceramic carrier 5. The shape of the SiC honeycomb ceramic carrier 5 is consistent with that of the encapsulation shell 7. For example, if the shape of the encapsulation shell 7 is a cuboid, then the shape of the SiC honeycomb ceramic carrier 5 is also a cuboid.

[0045] refer to Figure 1 As one implementation method, the active component of the catalyst is a combination of one or more components of platinum, palladium or copper, or the corresponding active component of the catalyst can be changed according to the type of target waste gas.

[0046] This invention also discloses a waste gas treatment method, which uses the waste gas treatment device described above, characterized by mainly including the following steps: When the device is powered on, the current flows through the SiC honeycomb ceramic carrier 5, and the resistance of the carrier generates Joule heat, causing the SiC honeycomb ceramic carrier 5 to rapidly heat up to the predetermined catalytic reaction temperature (e.g., 200-450℃) within tens of seconds to several minutes.

[0047] The waste gas to be treated (such as kitchen fumes or industrial exhaust gas) is introduced into the device through the air inlet opened on the pressure plate 1, and then passes through the SiC honeycomb ceramic carrier 5 which has been heated to the working temperature.

[0048] Within the SiC honeycomb ceramic carrier 5, the exhaust gas undergoes an oxidative decomposition reaction under the combined action of a catalyst and a suitable temperature, transforming pollutants into harmless substances such as carbon dioxide, water, and nitrogen.

[0049] The treated clean gas is discharged through the outlet on the pressure plate 1. The entire process is controlled in a closed loop by the temperature sensor 8 and the controller to maintain the optimal reaction temperature and adapt to fluctuations in the waste gas concentration.

[0050] This invention has the advantages of fast preheating speed and high energy efficiency, and can be miniaturized and modularized, supporting online processing. It can significantly expand the application scenarios and improve economic efficiency. The conductive heating porous ceramic carrier used is SiC honeycomb ceramic carrier 5 (the pore density of the honeycomb is 200-600 CPSI, the thickness of the wall between the honeycomb channels is 7-12 mil, and the preferred parameters of the honeycomb structure are 300 CPSI / 9 mil). It has excellent thermal conductivity and stability, large specific surface area, low pressure loss, and its production and catalyst coating process is mature and stable.

[0051] Example 1 1. Synthesis of Platinum / Palladium-based Catalysts Based on Silicon Carbide Honeycomb Supports 1.1 Preparation of platinum-based supported powder catalyst: 5 g of platinum nitrate or palladium nitrate was dissolved in 500 mL of deionized water, and then 120 g of Ce was added. 0.5 Zr 0.5 O2 and 80 g of γ-Al2O3 powder were thoroughly mixed and then the solution was evaporated by stirring at 80°C. Subsequently, the solution was calcined at 550°C in air for 3 h to form powder.

[0052] 1.2 Preparation of slurry: Add 200 g of the above powder to 500 mL of deionized water, along with 4.2 g of methylcellulose and 35 g of boehmite, and stir for 1 h to ensure uniform mixing and form a catalyst slurry of suitable viscosity.

[0053] 1.3 Catalyst Coating: A certain mass of slurry is applied to the honeycomb silicon carbide substrate using a coating machine at a loading rate of 100 g / L. The substrate is then calcined in a muffle furnace at 550 °C for 3 h to obtain a platinum-based catalyst based on a silicon carbide honeycomb support.

[0054] 2. Integrated electrically heated reactor 2.1 First, the platinum-based catalyst based on silicon carbide honeycomb carrier is encapsulated according to the process described in the drawings and specific implementation method. The left and right ends of the catalyst are connected to conductive metal electrodes respectively, and the other ends of the two electrodes are connected to a 48V power supply respectively.

[0055] 2.2 Turn on the power supply and apply a current of 7~10 A to the platinum-based catalyst on the silicon carbide honeycomb support, using a power of 235~480 W. Control the output power based on the temperature feedback from the thermocouple, and ensure that the catalyst bed temperature is stable at a specific temperature value between 200~300℃ according to the actual temperature requirements.

[0056] 3. Verification of technical effectiveness This system can be used for the removal of volatile organic compounds (VOCs) from restaurant fumes. (In 60,000 h) -1 Under air velocity conditions, the effect of electric field catalysis on pollutants in a real exhaust environment of catering fumes was tested. Samples were taken using sampling bags, and the conversion rates of various pollutants before and after catalytic treatment were compared. The technical results obtained are as follows:

[0057] It should be noted that, for those skilled in the art, it is obvious that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A waste gas treatment device, characterized in that, It includes a packaging shell (7), a SiC honeycomb ceramic carrier (5) disposed inside the packaging shell (7), and a catalyst for the target waste gas disposed on the SiC honeycomb ceramic carrier (5). Both ends of the SiC honeycomb ceramic carrier (5) are connected to an external power source, and both ends of the packaging shell (7) are provided with gas channels.

2. The waste gas treatment device according to claim 1, characterized in that, It also includes pressure plates (1) disposed at both ends of the encapsulation shell (7) for pressing the SiC cell ceramic carrier (5), and an insulation mechanism disposed on the outer periphery of the SiC cell ceramic carrier (5), wherein the gas channel is disposed on the pressure plate (1).

3. The waste gas treatment device according to claim 2, characterized in that, The two ends of the SiC honeycomb ceramic carrier (5) are connected to the external power source through perforated plates (3).

4. The waste gas treatment device according to claim 3, characterized in that, An elastic contact mesh (4) is provided between the perforated plate (3) and the SiC honeycomb ceramic carrier (5).

5. The waste gas treatment device according to claim 3, characterized in that, A wire outlet (10) is provided on the orifice plate (3) located at one end, and the wire outlet (10) is used for the wires of the orifice plate (3) at the other end to pass through and connect to the external power source.

6. The waste gas treatment device according to claim 3, characterized in that, The insulation mechanism includes an insulating liner (6) disposed between the SiC cell ceramic carrier (5) and the encapsulation shell (7), and an insulating gasket (2) disposed between the pressure plate (1) and the perforated plate (3).

7. The waste gas treatment device according to claim 6, characterized in that, The insulating liner (6) is made of mica, refractory brick or glass fiber.

8. The waste gas treatment device according to claim 6, characterized in that, The insulating liner (6) has an installation groove on the side near the SiC cell ceramic carrier (5), and a temperature sensor (8) is installed in the installation groove.

9. The waste gas treatment device according to claim 1, characterized in that, The SiC honeycomb ceramic carrier (5) has a honeycomb three-dimensional structure.

10. A method for treating waste gas, using the waste gas treatment apparatus as described in any one of claims 1-9, characterized in that, The main steps include: Connect the SiC honeycomb ceramic support (5) to an external power source so that the SiC honeycomb ceramic support (5) reaches the predetermined catalyst reaction temperature; The exhaust gas enters from one end of the gas channel, is decomposed by the SiC honeycomb ceramic carrier (5), and is discharged from the other end of the gas channel.

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