A regenerator structure for a regenerative oxidizer for treating waste gases containing methyl nitrite

Abstract

This utility model discloses a regenerator structure for treating regenerative thermal oxidizers (RTOs) containing methyl nitrite waste gas. It relates to the technical field of RTOs and includes an RTO furnace body. A honeycomb ceramic regenerator is located on the upper side of the RTO furnace body. The area within the RTO furnace body where the uniformly distributed honeycomb ceramic regenerators are installed is the decomposition zone. The area within the RTO furnace body where large-pore ceramic regenerators are installed is the preheating zone. The flue gas passes through the large-pore ceramic regenerator, the uniformly distributed honeycomb ceramic regenerator, and the honeycomb ceramic regenerator sequentially from bottom to top. A thermal resistor is horizontally installed on the inner wall of the RTO furnace body. This utility model solves the temperature shock caused by the heat released during the decomposition of methyl nitrite in the low-temperature region of the lower layer of the RTO regenerator ceramic, maintaining the thermal balance of the regenerator ceramic. This allows the RTO to treat methyl nitrite waste gas with concentrations of 3% LEL to 15% LEL, achieving high treatment efficiency. During the treatment process, the temperature of the lower layer of the regenerator ceramic can be stably controlled below 400℃, ultimately enabling the regenerative thermal oxidizer to stably and efficiently treat high-concentration methyl nitrite waste gas.

Description

Technical Field

[0001] Specifically, this utility model relates to a regenerator chamber structure for a regenerator-type oxidizer used to treat waste gas containing methyl nitrite. Background Technology

[0002] Methyl nitrite is an important intermediate product in coal chemical industry, biopharmaceutical industry, and organic synthesis. It is easily decomposed when heated or exposed to light, causing a rapid increase in temperature and pressure. Methyl nitrite begins to decompose exothermically around 140℃, reaches its peak exothermic temperature at 220℃, and the exothermic process is essentially complete at 300℃. Its heat of decomposition is 3216 kJ / kg. Therefore, the thermal decomposition of methyl nitrite is a strongly exothermic reaction and is highly dangerous.

[0003] Thermal decomposition products: methanol, formaldehyde, and NO. The thermal decomposition equation for methyl nitrite is: 2CH3ONO=CH3OH+HCHO+2NO.

[0004] For low-concentration methyl nitrite waste gas, alkaline absorption and activated carbon adsorption are generally used, but the removal efficiency is only about 80%, and secondary pollutants such as waste liquid and waste activated carbon will also be generated.

[0005] The existing patent, "A Waste Gas Treatment System for Methyl Nitrite" (CN 204865499 U), describes a treatment system that uses a sodium carbonate-ethanolamine mixed solution to absorb methyl nitrite waste gas. In the alkaline scrubbing tower, ethanolamine is used as a co-solvent to increase the solubility of both sodium carbonate solution and methyl nitrite, thereby improving the reaction efficiency between them and ultimately increasing the waste gas treatment efficiency. This invention expands the system's applicability to methyl nitrite waste gas concentrations by incorporating multiple alkaline scrubbing towers.

[0006] However, the alkaline washing method has a maximum treatment efficiency of no more than 85% for methyl nitrite waste gas, and can treat a maximum waste gas concentration of no more than 1000 ppm (2% LEL); at the same time, it will also generate nitrite wastewater, which requires secondary treatment.

[0007] For high-concentration methyl nitrite waste gas (concentration > 3% LEL), thermal combustion can completely oxidize it into CO2 and H2O at 800℃, with a removal efficiency of over 99%. Regenerative Thermal Oxidizers (RTOs) are very suitable for treating high-concentration methyl nitrite waste gas. However, during testing, methyl nitrite rapidly decomposed in the lower layer of regenerative ceramics, causing the temperature of the ceramic layer to shift upwards. Simultaneously, the center temperature of the same ceramic layer was much higher than the surrounding area. Within several RTO switching cycles, the thermal balance of the regenerative chamber was disrupted, with the local temperature of the lower layer of the regenerative ceramics exceeding 600℃, leading to local structural deformation of the regenerative chamber and making stable RTO operation impossible. Utility Model Content

[0008] The purpose of this invention is to provide a regenerator chamber structure for a regenerator oxidizer used to treat waste gas containing methyl nitrite, so as to solve the problems mentioned in the background art.

[0009] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a regenerator structure for a regenerator-type oxidation furnace for treating waste gas containing methyl nitrite, comprising an RTO furnace body, wherein a honeycomb ceramic regenerator is provided on the upper side of the RTO furnace body;

[0010] The RTO furnace body is equipped with a uniformly distributed honeycomb ceramic heat storage body, and the location where the uniformly distributed honeycomb ceramic heat storage body is installed in the RTO furnace body is the decomposition zone.

[0011] The RTO furnace body is also equipped with a large-pore ceramic heat storage body, and the location where the large-pore ceramic heat storage body is installed in the RTO furnace body is the preheating zone.

[0012] The honeycomb ceramic heat storage body, the uniformly distributed honeycomb ceramic heat storage body, and the large-pore ceramic heat storage body are distributed sequentially from top to bottom, and the flue gas passes through the large-pore ceramic heat storage body, the uniformly distributed honeycomb ceramic heat storage body, and the honeycomb ceramic heat storage body sequentially from bottom to top.

[0013] The inner wall of the RTO furnace is provided with two thermal resistors in the horizontal direction. A waste gas mixing zone is provided above both the decomposition zone and the preheating zone. The upper thermal resistor is located in the waste gas mixing zone above the decomposition zone, and the lower thermal resistor is located in the waste gas mixing zone above the preheating zone.

[0014] In a further embodiment, an H-beam is fixed to the bottom of the large-aperture ceramic regenerator, and the H-beam is welded to the steel plate on the side wall of the RTO furnace.

[0015] In a further embodiment, a layer of metal wire mesh is fixed to the top of the large-aperture ceramic heat storage body;

[0016] The upper end of the large-pore ceramic heat storage body has one or more layers of heat storage bricks.

[0017] In a further embodiment, an H-beam is also fixed to the bottom of the uniformly distributed honeycomb ceramic regenerator, and the H-beam is welded to the steel plate on the side wall of the RTO furnace.

[0018] In a further embodiment, a layer of metal wire mesh is also fixed to the upper end of the uniformly distributed honeycomb ceramic heat storage body;

[0019] The heat storage bricks at the top of the uniformly distributed honeycomb ceramic heat storage body are laid in multiple layers.

[0020] In a further embodiment, the thermal resistor is installed in the waste gas mixing zone of the RTO furnace body, and the thermal resistor is horizontally installed on the side wall of the RTO furnace body via a flange or thread.

[0021] In a further embodiment, the outer wall of the RTO furnace is covered with an RTO insulation structure.

[0022] In a further embodiment, an H-beam is also fixed to the bottom of the honeycomb ceramic heat storage body, and the H-beam is welded to the steel plate on the side wall of the RTO furnace body.

[0023] In a further embodiment, a layer of metal wire mesh is also fixed to the upper end of the honeycomb ceramic heat storage body;

[0024] The heat storage bricks at the top of the honeycomb ceramic heat storage body are laid in multiple layers.

[0025] Compared with the prior art, the beneficial effects of this utility model are:

[0026] This invention relates to a regenerative thermal oxidizer (RTO) structure for treating waste gas containing methyl nitrite. It addresses the temperature shock caused by the heat released during the decomposition of methyl nitrite in the low-temperature region (140℃~300℃) of the lower layer of the RTO regenerative ceramic, maintaining the thermal balance of the ceramic. This allows the RTO to treat methyl nitrite waste gas with concentrations of 3% LEL to 15% LEL, achieving a treatment efficiency >99%. During the treatment process, the temperature of the lower layer of the regenerative ceramic can be stably controlled below 400℃, ultimately enabling the RTO to stably and efficiently treat high-concentration methyl nitrite waste gas. The RTO completely oxidizes the methyl nitrite waste gas into CO2 and H2O. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the internal structure of the main body of this utility model embodiment.

[0028] In the diagram: 1. RTO furnace body; 2. Resistance temperature detector (RTD); 3. Large-pore ceramic regenerator; 4. Uniformly distributed honeycomb ceramic regenerator; 5. Honeycomb ceramic regenerator; 6. RTO insulation structure. Detailed Implementation

[0029] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0030] This embodiment provides a regenerator chamber structure for a regenerative oxidizer used to treat waste gas containing methyl nitrite, such as... Figure 1As shown, the system includes an RTO furnace body 1, in which a regenerative thermal oxidizer (RTO) is used: Waste gas is first heated to near its thermal oxidation temperature by a regenerator, and then enters the combustion chamber for thermal oxidation. The oxidized gas has an increased temperature, and organic matter is essentially converted into carbon dioxide and water. The purified gas then passes through another regenerator, where its temperature decreases, and it can be discharged after meeting emission standards. An RTO insulation structure 6 is installed on the outer wall of the RTO furnace body 1, providing good insulation.

[0031] A honeycomb ceramic heat storage body 5 is installed on the upper side of the RTO furnace body 1. An H-beam is also fixed to the bottom of the honeycomb ceramic heat storage body 5, and the H-beam is welded to the steel plate on the side wall of the RTO furnace body 1. A layer of metal wire mesh is also fixed to the upper end of the honeycomb ceramic heat storage body 5. The heat storage bricks on the upper end of the honeycomb ceramic heat storage body 5 are laid in multiple layers, and the metal wire mesh prevents the heat storage bricks from shifting during operation.

[0032] The RTO furnace body 1 is equipped with a uniformly distributed honeycomb ceramic regenerator 4. An H-beam is fixed to the bottom of the uniformly distributed honeycomb ceramic regenerator 4, and the H-beam is welded to the steel plate on the side wall of the RTO furnace body 1. A layer of metal wire mesh is also fixed to the upper end of the uniformly distributed honeycomb ceramic regenerator 4. Multiple layers of heat storage bricks are laid flat on the upper end of the uniformly distributed honeycomb ceramic regenerator 4, and the metal wire mesh prevents the heat storage bricks from shifting during operation. The location within the RTO furnace body 1 where the uniformly distributed honeycomb ceramic regenerator 4 is installed is the decomposition zone.

[0033] The RTO furnace body 1 also contains a large-pore ceramic heat storage body 3. An H-beam is fixed to the bottom of the large-pore ceramic heat storage body 3, and the H-beam is welded to the steel plate on the side wall of the RTO furnace body 1. A layer of metal wire mesh is fixed to the top of the large-pore ceramic heat storage body 3. One or more layers of heat storage bricks are arranged on the upper part of the large-pore ceramic heat storage body 3, and the metal wire mesh prevents the heat storage bricks from shifting during operation. The location where the large-pore ceramic heat storage body 3 is installed inside the RTO furnace body 1 is the preheating zone. The large-pore ceramic heat storage body 3 uses a flat arrangement of large-pore honeycomb ceramic heat storage bricks to fully and uniformly preheat the room-temperature methyl nitrite waste gas to 100–120°C within this zone.

[0034] The upper part of the waste gas mixing zone is the decomposition zone, which uses uniformly distributed honeycomb ceramic heat storage bodies (4) arranged in a flat assembly. Each of the 4 heat storage bodies is a cube with interconnected honeycomb-shaped holes. Large circular holes are located on all four side walls of the cube. The heat storage bodies (4) are made of composite ceramics with low thermal expansion coefficients, good thermal shock resistance, good corrosion resistance, and moderate thermal conductivity.

[0035] The honeycomb ceramic heat storage element 5, the uniformly distributed honeycomb ceramic heat storage element 4, and the large-pore ceramic heat storage element 3 are distributed sequentially from top to bottom. The flue gas passes through the large-pore ceramic heat storage element 3, the uniformly distributed honeycomb ceramic heat storage element 4, and the honeycomb ceramic heat storage element 5 sequentially from bottom to top. This ensures that the flow field of the waste gas is uniform within the decomposition zone, and the heat released by the decomposition of methyl nitrite is evenly conducted to the surrounding area through the heat storage ceramic bricks, without generating localized thermal stress on the ceramic bricks.

[0036] The temperature of the upper layer of the decomposition zone is controlled at 320-350℃ to ensure that methyl nitrite is completely decomposed into methanol, formaldehyde and NO within the decomposition zone.

[0037] Two thermal resistors 2 are horizontally installed on the inner wall of the RTO furnace body 1. A waste gas mixing zone is located above both the decomposition zone and the preheating zone. The upper thermal resistor 2 is located in the waste gas mixing zone above the decomposition zone, and the lower thermal resistor 2 is located in the waste gas mixing zone above the preheating zone. The thermal resistors 2 are horizontally installed on the side wall of the RTO furnace body 1 via flanges or threads. The height of the waste gas mixing zone is 100-150mm to ensure uniform mixing of the preheated waste gas. A thermal resistor 2 with an insertion depth of 1000mm is installed at the center of this zone to monitor the preheated waste gas temperature in real time (350℃ < waste gas temperature < 400℃).

[0038] The upper part of the exhaust gas mixing zone and the RTO furnace body 1 are all composed of honeycomb ceramic regenerators 5 with conventional apertures. They are made of multiple layers of regenerating ceramic bricks laid flat and occupy the upper 2 / 3 of the regenerator chamber.

[0039] The waste gas, which decomposes into methanol, formaldehyde, and NO, is heated in the upper two-thirds of the regenerator before entering the RTO furnace 1, where it is completely oxidized into CO2 and H2O.

[0040] In summary, this application addresses the problem of rapid thermal decomposition of methyl nitrite waste gas in the lower heat storage ceramic (low-temperature zone) of the RTO by modifying the structure of the RTO furnace body 1, especially by optimizing the design of the lower part of the heat storage chamber. This addresses the issue of local overheating and over-temperature of the lower heat storage ceramic, which in turn damages the internal structure. Ultimately, this enables the RTO equipment to be used for the treatment of high-concentration methyl nitrite waste gas.

[0041] This application ensures stable exhaust gas temperature entering the decomposition zone by setting up a preheating zone; uniformly distributed honeycomb ceramic bricks made of composite materials are used in the decomposition zone to ensure uniform heating of methyl nitrite exhaust gas within the decomposition zone, and the heat generated by decomposition can be stably conducted through the heat storage bricks to avoid local thermal shock and local overheating; by setting up an exhaust gas mixing zone, the exhaust gas entering and leaving the decomposition zone is ensured to be mixed evenly, and the exhaust gas temperature is stable and controllable; by setting up a thermal resistor 2 in the exhaust gas mixing zone, the temperature of the decomposition zone is ensured to be controlled within 120-350℃, covering the entire decomposition temperature range of methyl nitrite.

[0042] The RTO using the heat storage chamber structure of this application can treat high-concentration methyl nitrite waste gas at temperature with a removal efficiency of >99%.

[0043] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A structure of a regenerator for a regenerative oxidizer for treating exhaust gas containing methyl nitrite, characterized by comprising: include: RTO furnace body (1), wherein a honeycomb ceramic heat storage body (5) is provided on the upper side of the RTO furnace body (1); The RTO furnace body (1) is equipped with a uniformly distributed honeycomb ceramic heat storage body (4), and the location where the uniformly distributed honeycomb ceramic heat storage body (4) is installed in the RTO furnace body (1) is the decomposition zone; The RTO furnace body (1) is also equipped with a large-pore ceramic heat storage body (3), and the location where the large-pore ceramic heat storage body (3) is installed in the RTO furnace body (1) is the preheating zone; The honeycomb ceramic heat storage body (5), the uniformly distributed honeycomb ceramic heat storage body (4) and the large-pore ceramic heat storage body (3) are distributed from top to bottom, and the flue gas passes through the large-pore ceramic heat storage body (3), the uniformly distributed honeycomb ceramic heat storage body (4) and the honeycomb ceramic heat storage body (5) from bottom to top. The inner wall of the RTO furnace body (1) is provided with two thermal resistors (2) in the horizontal direction. A waste gas mixing zone is provided above the decomposition zone and the preheating zone. The upper thermal resistor (2) is located in the waste gas mixing zone above the decomposition zone, and the lower thermal resistor (2) is located in the waste gas mixing zone above the preheating zone.

2. The regenerator structure of the regenerative thermal oxidizer for treating the waste gas containing the methyl nitrite according to claim 1, wherein The bottom of the large-aperture ceramic heat storage body (3) is fixed with an H-beam, which is welded to the steel plate on the side wall of the RTO furnace body (1).

3. The regenerator structure of the regenerative thermal oxidizer for treating the waste gas containing the methyl nitrite according to claim 2, wherein A layer of metal wire mesh is fixed at the top of the large-pore ceramic heat storage body (3); The upper end of the large-pore ceramic heat storage body (3) has one or more layers of heat storage bricks.

4. The regenerator structure of the regenerative thermal oxidizer for treating a waste gas containing methyl nitrite according to claim 1, wherein The bottom of the uniformly distributed honeycomb ceramic heat storage body (4) is also fixed with an H-beam, which is welded to the steel plate on the side wall of the RTO furnace body (1).

5. The regenerator structure of the regenerative thermal oxidizer for treating a waste gas containing methyl nitrite according to claim 1, wherein A layer of metal wire mesh is also fixed at the upper end of the uniformly distributed honeycomb ceramic heat storage body (4); The heat storage bricks at the top of the uniformly distributed honeycomb ceramic heat storage body (4) are laid in multiple layers.

6. The regenerator structure of the regenerative thermal oxidizer for treating a waste gas containing methyl nitrite according to claim 5, wherein The position where the thermal resistor (2) is installed inside the RTO furnace body (1) is the waste gas mixing zone. The thermal resistor (2) is horizontally installed on the side wall of the RTO furnace body (1) by means of flange or thread.

7. The regenerator chamber structure of the regenerative oxidizer for treating methyl nitrite-containing waste gas according to claim 1, characterized in that, The outer wall of the RTO furnace body (1) is covered with an RTO insulation structure (6).

8. The regenerator structure of the regenerative thermal oxidizer for treating a waste gas containing methyl nitrite according to claim 1, wherein The bottom of the honeycomb ceramic heat storage body (5) is also fixed with an H-beam, which is welded to the steel plate on the side wall of the RTO furnace body (1).

9. The regenerator structure of the regenerative thermal oxidizer for treating a waste gas containing methyl nitrite according to claim 8, wherein A layer of metal wire mesh is also fixed to the upper end of the honeycomb ceramic heat storage body (5); The heat storage bricks at the top of the honeycomb ceramic heat storage body (5) are laid in multiple layers.

Images