Engine exhaust gas staged treatment device

Abstract

The utility model provides a kind of engine exhaust grading treatment device, it is related to tail gas treatment technical field to solve the technical problem of narrow temperature window of single treatment method of aviation field exhaust suitable for. The grading treatment device, the open end of injection pipe is towards the tail nozzle of aeroengine, the closed end of injection pipe extends to the inside of ventilation tower;It also includes first catalyst purification unit, second catalyst purification unit and third catalyst purification unit;First catalyst purification unit is arranged in the inside of injection pipe close to open end;Second catalyst purification unit is arranged in the inside of injection pipe close to closed end;Third catalyst purification unit is arranged in ventilation tower and is sleeved in the outer periphery of injection pipe;Wherein, first catalyst purification unit is filled with ternary catalyst;Second catalyst purification unit is filled with oxidation type catalyst;Third catalyst purification unit is filled with selective catalytic reduction catalyst. The grading treatment device widens overall temperature adaptation window.

Description

Technical Field

[0001] This utility model relates to the field of exhaust gas treatment technology, and in particular to an engine exhaust gas staged treatment device. Background Technology

[0002] During the testing of the aero-engine, the exhaust gas temperature, velocity, and pollutant concentration at the tail nozzle were all relatively high, with the concentrations of major pollutants such as nitrogen oxides and unburned hydrocarbons reaching 500 mg / m³. 3 The above describes the process. After being diluted by the ejector gas flow, the exhaust gas temperature, velocity, and pollutant concentration decrease. After being evenly mixed in the test bench injection pipe, it is discharged from the ventilation tower.

[0003] The exhaust gas temperature range of aircraft engines is from tens to hundreds of degrees Celsius. Conventional exhaust gas treatment methods, such as spraying, adsorption, electrostatic precipitator or catalysis, are only applicable to a narrow temperature window in the aviation field. Utility Model Content

[0004] The purpose of this invention is to provide an engine exhaust gas staged treatment device to solve the technical problem that the temperature window applicable to a single exhaust gas treatment method in the aviation field is narrow.

[0005] To achieve the above objectives, this utility model provides the following technical solution:

[0006] This utility model provides an engine exhaust gas staged treatment device, wherein the exhaust gas is the exhaust gas generated during the test of an aero-engine; the staged treatment device includes an injection pipe and a ventilation tower, the injection pipe has an open end and a closed end, the open end of the injection pipe faces the exhaust nozzle of the aero-engine, and the closed end of the injection pipe extends into the ventilation tower.

[0007] The graded treatment device also includes a first catalyst purification unit, a second catalyst purification unit and a third catalyst purification unit;

[0008] The first catalyst purification unit is located inside the injection pipe near the open end; the second catalyst purification unit is located inside the injection pipe near the closed end; the third catalyst purification unit is located inside the ventilation tower and sleeved on the outer periphery of the injection pipe.

[0009] The first catalyst purification unit is filled with a ternary catalyst; the second catalyst purification unit is filled with an oxidizing catalyst; and the third catalyst purification unit is filled with a selective catalytic reduction catalyst.

[0010] According to at least one embodiment of the present invention, the third catalyst purification unit includes a plurality of injection heads, the plurality of injection heads being arranged in an array on the outer periphery of the injection tube, and each of the injection heads being directed toward the selective catalytic reduction catalyst.

[0011] According to at least one embodiment of the present invention, the second catalyst purification unit includes a second frame structure, the second frame structure being a cylindrical structure and coaxial with the injection pipe;

[0012] The oxidized catalyst is filled on the second framework structure.

[0013] According to at least one embodiment of the present invention, the third catalyst purification unit includes a third frame structure, which is a cylindrical structure and sleeved on the outer periphery of the injection pipe, and is coaxial with the injection pipe.

[0014] The selective catalytic reduction catalyst is packed on a third framework structure.

[0015] According to at least one embodiment of the present invention, the first catalyst purification unit includes a first frame structure, which is an annular structure and connected to the inner wall of the injection pipe.

[0016] The ternary catalyst is filled within the first frame structure.

[0017] According to at least one embodiment of the present invention, a plurality of ventilation holes are provided on the peripheral side of the portion of the injection pipe located inside the ventilation tower.

[0018] According to at least one embodiment of the present invention, the inner wall of the end face of the closed end has a flow guide cone;

[0019] The guide cone has a conical structure, with its bottom surface located on the end face and its top extending toward the opening end.

[0020] According to at least one embodiment of the present invention, a plurality of the vent holes are evenly distributed on the peripheral surface of the injection pipe; or,

[0021] The distribution density of the vent holes gradually increases along the direction from the open end to the closed end.

[0022] According to at least one embodiment of the present invention, the graded treatment device further includes a storage tank for storing a reducing agent, the storage tank being connected to a plurality of the spray heads via a pipeline.

[0023] According to at least one embodiment of the present invention, the resistance of the catalyst in the first catalyst purification unit, the second catalyst purification unit and the third catalyst purification unit is less than or equal to 500 Pa.

[0024] In one or more technical solutions provided in the exemplary embodiments of this utility model, at least one of the following beneficial effects can be achieved.

[0025] The exemplary embodiment of this invention discloses an engine exhaust gas staged treatment device, comprising an injection pipe and a ventilation tower. The injection pipe has an open end and a closed end, with the open end facing the exhaust nozzle of the aero-engine and the closed end extending into the ventilation tower. High-temperature exhaust gas ejected from the aero-engine's exhaust nozzle enters the injection pipe from the open end and mixes with external air under the influence of the ejector. As the airflow moves along the injection pipe towards the closed end, the temperature gradually becomes more uniform and decreases to the temperature range where the catalyst reacts efficiently. Specifically, a first catalyst purification unit is located inside the injection pipe near the open end and is filled with a three-way catalyst. In this region, the exhaust gas and the ejector air are unevenly mixed, resulting in higher exhaust gas velocity, temperature, and pollutant concentration. The three-way catalyst can effectively purify the exhaust gas simultaneously using oxidation and reduction reactions against nitrogen oxides and hydrocarbons under high temperature and high flow rate conditions.

[0026] Furthermore, the second catalyst purification unit is located inside the injection pipe near the closed end, and its interior is filled with an oxidizing catalyst. In this area, the exhaust gas temperature and flow rate are uniform. The oxidizing catalyst can facilitate the targeted treatment of hydrocarbons in the exhaust gas, using oxidation reactions to purify the hydrocarbons in the exhaust gas.

[0027] Furthermore, the third catalyst purification unit is located inside the ventilation tower and fitted around the outer periphery of the injection pipe. It is filled with a selective catalytic reduction catalyst. In this area, the exhaust gas velocity is lowest and the temperature is most uniform, which is more conducive to the decomposition of the reducing agent and improves the purification efficiency of the selective catalytic reduction catalyst. Based on this, through the synergistic effect of the three-stage catalysts, efficient graded treatment of pollutants in aero-engine exhaust gas under different temperatures and flow rates is achieved, significantly improving the removal efficiency of major pollutants such as nitrogen oxides and hydrocarbons, thereby effectively broadening the overall temperature adaptability window of the engine exhaust gas graded treatment device. Attached Figure Description

[0028] The accompanying drawings illustrate exemplary embodiments of the present invention and, together with the description thereof, serve to explain the principles of the present invention. These drawings are included to provide a further understanding of the present invention and are incorporated in and constitute a part of this specification.

[0029] Figure 1 This is a schematic diagram of the structure of the graded treatment device according to an embodiment of the present utility model;

[0030] Figure 2 This is a schematic diagram of the first frame structure according to an embodiment of the present utility model;

[0031] Figure 3 This is a cross-sectional structural diagram of a ventilation tower according to an embodiment of the present invention.

[0032] Figure label:

[0033] 10. Injection pipe; 11. Open end; 12. Guide cone;

[0034] 21. First catalyst purification unit; 211. First frame structure; 22. Second catalyst purification unit; 23. Third catalyst purification unit; 24. Atomizing nozzle;

[0035] 30. Ventilation tower. Detailed Implementation

[0036] To make the technical problem to be solved, the technical solution, and the beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0037] The test conditions for aero engines change frequently, with different exhaust volumes and temperatures for each test condition. The temperature range of the exhaust section on the test stand is from tens to hundreds of degrees Celsius, and the exhaust velocity ranges from a few meters to hundreds of meters per second.

[0038] The treatment technologies used in related technologies for handling exhaust gases from aircraft engine tests have the following drawbacks, as shown in Table 1.

[0039] Table 1 Comparison of Exhaust Gas Treatment Technologies

[0040]

[0041] As shown in Table 1, existing exhaust gas treatment technologies struggle to simultaneously meet the requirements of high efficiency, energy saving, and wide temperature range adaptability. This is especially true in complex and variable operating conditions such as aero-engine testing, where a single technological approach has significant limitations. This invention utilizes a multi-stage catalytic and ejector-assisted mixed-flow approach, specifically adapting different catalyst purification units to different temperature and flow rate regions. This significantly improves pollutant purification efficiency across all operating conditions, achieving exhaust gas treatment under a wide temperature range.

[0042] It should be noted that, unless otherwise specified, the catalysts described in this utility model are all commercially available and mature products.

[0043] Example 1

[0044] Figure 1 This is a schematic diagram of the structure of the graded treatment device according to an embodiment of the present utility model; Figure 3 This is a cross-sectional structural schematic diagram of a ventilation tower according to an embodiment of the present invention. (In conjunction with...) Figure 1 and Figure 3 As shown, the graded treatment device provided in the exemplary embodiment of this utility model includes an injection pipe 10 and a ventilation tower 30. The injection pipe 10 has an open end 11 and a closed end. The open end 11 of the injection pipe 10 faces the tail nozzle of the aero-engine, and the closed end of the injection pipe 10 extends into the ventilation tower 30. The graded treatment device also includes a first catalyst purification unit 21, a second catalyst purification unit 22, and a third catalyst purification unit 23. The first catalyst purification unit 21 is disposed inside the injection pipe 10 near the open end 11. The second catalyst purification unit 22 is disposed inside the injection pipe 10 near the closed end. The third catalyst purification unit 23 is disposed inside the ventilation tower 30 and sleeved on the outer periphery of the injection pipe 10. The first catalyst purification unit 21 is filled with a three-way catalyst. The second catalyst purification unit 22 is filled with an oxidizing catalyst. The third catalyst purification unit 23 is filled with a selective catalytic reduction catalyst.

[0045] In practical applications, the aircraft engine is installed in a room, and the open end 11 of the jet pipe 10 is installed on the wall of the room and aligned with the engine exhaust nozzle. The closed end of the jet pipe 10 extends into the ventilation tower 30 through the wall of the ventilation tower 30. Multiple ventilation holes are provided on the peripheral wall of the part of the jet pipe 10 located inside the ventilation tower 30 to connect the interior of the jet pipe 10 with the ventilation tower 30.

[0046] When the high-temperature exhaust gas emitted during engine testing enters the injection pipe 10, it is mixed with external air under the influence of the high-speed airflow, achieving initial cooling and mixing. In the front region of the injection pipe 10, the exhaust gas and the ejected air are unevenly mixed, resulting in high exhaust gas velocity, temperature, and pollutant concentration. The exhaust gas velocity is approximately hundreds of meters per second, the maximum temperature exceeds 400℃, and under certain operating conditions, the pollutant concentration is ≥500 mg / m³. 3 Within this area, a first catalyst purification unit 21 is installed, utilizing the simultaneous conversion capability of a three-way catalyst for CO, HC, and NOx under high temperature and high flow rate conditions to achieve rapid reduction of initial pollutants.

[0047] Figure 2 This is a schematic diagram of the first frame structure according to an embodiment of the present utility model. (See diagram below.) Figure 2As shown, the first catalyst purification unit 21 includes a first frame structure 211, which is an annular structure and connected to the inner wall of the injection pipe 10; the three-way catalyst is filled in the first frame structure 211, and the outline of the first frame structure 211 matches the inner wall of the injection pipe 10 to ensure that the airflow passes through the three-way catalyst layer uniformly.

[0048] For example, the three-way catalyst is arranged in blocks within each grid of the first frame structure 211. In order to maintain the stability of the first frame structure 211, a support is provided at the bottom of the first frame structure 211 and an inclined support connected to the support is provided at its rear.

[0049] For example, a three-way catalyst is filled within the first frame structure 211 and arranged along the cross-section of the injection pipe 10. The resistance of the three-way catalyst is configured to be less than or equal to 500 Pa to ensure the passage of high-speed gas flow and effective catalytic treatment.

[0050] The aforementioned three-way catalyst is placed within the first frame structure 211 and within the injection pipe 10 for easy installation and maintenance, while ensuring its structural stability under high temperature and high flow rate conditions.

[0051] As the exhaust gas flows towards the closed end of the injection pipe 10, its temperature and flow rate gradually decrease, entering the area where the second catalyst purification unit 22 is located. The average flow rate in this area is approximately tens of meters per second, and the average temperature is above 200°C. Under these conditions, the oxidizing catalyst can effectively promote the deep oxidation of CO and HC, further reducing harmful emissions.

[0052] For example, the overall structure of the second catalyst purification unit 22 is cylindrical, and the inner diameter of the injection pipe 10 matches the outer diameter of the second catalyst purification unit 22, or the inner diameter of the injection pipe 10 is slightly larger than the outer diameter of the second catalyst purification unit 22, so as to ensure the ease of installation of the device and the uniformity of airflow distribution; thereby enabling the airflow to pass evenly through the honeycomb channels of the catalyst carrier and be discharged into the ventilation tower 30 through the vent of the injection pipe 10.

[0053] Specifically, the second catalyst purification unit 22 includes a second frame structure, which is a cylindrical structure and coaxial with the injection pipe 10; the oxidizing catalyst is filled on the second frame structure. The second frame structure is axially disposed in the portion of the injection pipe 10 located inside the ventilation tower 30.

[0054] After the exhaust gas flows out of the second catalyst purification unit 22, it enters the internal space of the ventilation tower 30 through the vent of the injection pipe 10, and is discharged from the third catalyst purification unit 23 which is sleeved on the outer periphery of the injection pipe 10. The third catalyst purification unit 23 includes a third frame structure, which is a cylindrical structure and is sleeved on the outer periphery of the injection pipe 10 and is coaxial with the injection pipe 10; the selective catalytic reduction catalyst is filled on the third frame structure.

[0055] In the area where the third catalyst purification unit 23 is located, the temperature is more uniform, the average exhaust gas flow rate is about 10 m / s, and the average temperature is higher than 200°C.

[0056] For example, the third frame structure is a cylindrical frame structure with a rectangular cross-section. A selective catalytic reduction (SCR) catalyst is disposed on the third frame structure. That is, the periphery walls (four side walls) of the third catalyst purification unit 23 are filled with honeycomb carriers with SCR catalyst coating to form an annular catalytic reaction zone for treating residual nitrogen oxides in the exhaust gas.

[0057] For example, the third catalyst purification unit 23 also includes an array of atomizing nozzles 24 located in an annular chamber between the rectangular frame structure and the outer wall of the injection pipe 10. The array of atomizing nozzles 24 is connected to a reducing agent supply system via pipelines to spray reducing agents (urea, ammonia, etc.) onto the catalyst on the third frame structure, ensuring that the reducing agent is fully atomized and uniformly mixed with the exhaust gas before entering the catalytic reaction zone, thereby improving the conversion efficiency of nitrogen oxides. Because the exhaust gas velocity is lower and the temperature is more uniform in the outer region of the injection pipe 10, with an average exhaust gas velocity of approximately 10 m / s and an average temperature above 200°C, it is conducive to the decomposition of the reducing agent, thereby improving purification efficiency. Within this temperature range, the SCR catalyst can achieve a nitrogen oxide conversion efficiency of over 85%. Combined with precise metering of the reducing agent and multi-point injection technology, local over- or under-reduction is further avoided, ensuring that emissions meet standards.

[0058] For example, the graded treatment device also includes a storage tank for storing reducing agent, which is connected to multiple spray heads via pipeline.

[0059] The storage tank contains an aqueous urea solution, and the atomizing nozzle 24 can evenly disperse the aqueous urea solution into the high-temperature exhaust gas. Ammonia is generated through a pyrolysis reaction, and then undergoes a selective catalytic reduction reaction with nitrogen oxides in the exhaust gas to produce harmless nitrogen and water vapor. This process maintains high efficiency even at low temperatures around 200℃, significantly reducing energy consumption and operating costs.

[0060] Example 1 presents a multi-stage treatment scheme using different catalysts based on different exhaust gas characteristics, as shown in Table 2.

[0061] Table 2 Exhaust Gas Staged Treatment Scheme

[0062]

[0063] Referring to Table 2, the graded treatment device provided by the exemplary embodiment of this utility model achieves efficient gradient removal of nitrogen oxides in exhaust gas through the step-by-step optimization of the three-stage catalytic reaction zone, so that the emissions of aero-engines under different test conditions are consistently lower than the limit standard, and the overall temperature adaptation window of the aero-engine exhaust gas graded treatment device is significantly widened.

[0064] Example 2

[0065] Based on Embodiment 1, the difference in this embodiment is that, in the graded treatment device provided by the exemplary embodiment of this utility model, the distribution density of the air vents in the part of the spray pipe 10 located inside the ventilation tower 30 gradually increases along the direction from the open end 11 to the closed end.

[0066] Correspondingly, the porosity of the oxidizing catalyst in the second catalyst purification unit 22 gradually increases along the axial direction. This satisfies the permeability and contact efficiency of the exhaust gas at different locations along the axial direction, while reducing airflow resistance. The gradient porosity design allows the airflow resistance to gradually decrease as it passes through each catalytic reaction zone, effectively avoiding local congestion and improving overall flow efficiency. Simultaneously, as the exhaust gas temperature decreases along the path, the increasing porosity can delay carbon buildup and poisoning on the catalyst surface, extending its service life.

[0067] Example 3

[0068] Based on Embodiment 1, the graded treatment device provided by the exemplary embodiment of this utility model has a guide cone 12 on the inner wall of the end face of the closed end; the guide cone 12 has a conical structure, the bottom surface of the guide cone 12 is located on the end face, and the top of the guide cone 12 extends toward the open end 11.

[0069] The guide cone 12 can effectively guide the airflow to turn smoothly, reduce turbulence and pressure loss, and increase the residence time and distribution uniformity of the exhaust gas in the part of the injection pipe 10 located in the ventilation tower 30, thereby improving the purification efficiency of the second catalyst purification unit 22.

[0070] Example 4

[0071] The difference between this embodiment and Embodiment 1 is that, as Figure 1As shown, the third catalyst purification unit 23 and the atomizing nozzle 24 are both positioned above the portion of the injection pipe 10 located inside the ventilation tower 30. The third frame structure of the third catalyst purification unit 23 is identical to the first frame structure 211 of the first catalyst purification unit 21, and its outer contour matches the shape of the inner wall of the ventilation tower 30; further details are omitted here. The selective catalytic reduction catalyst is packed in blocks within the grid of the third frame structure.

[0072] The atomizing nozzles 24 are arranged in an array above the portion of the injection pipe 10 located inside the ventilation tower 30, and all face the third catalyst purification unit 23. This embodiment effectively utilizes the rising airflow of exhaust gas within the ventilation tower 30, reducing wind resistance and saving costs compared to Embodiment 1.

[0073] Those skilled in the art should understand that the above embodiments are merely for clearly illustrating the present invention and are not intended to limit the scope of the present invention. Those skilled in the art can make other changes or modifications based on the above disclosure, and these changes or modifications still fall within the scope of the present invention.

Claims

1. An engine exhaust gas staged treatment device, characterized in that, The exhaust gas is the exhaust gas generated during the test of the aircraft engine; the graded treatment device includes an injection pipe and a ventilation tower, the injection pipe has an open end and a closed end, the open end of the injection pipe faces the tail nozzle of the aircraft engine, and the closed end of the injection pipe extends into the ventilation tower. The graded treatment device also includes a first catalyst purification unit, a second catalyst purification unit and a third catalyst purification unit; The first catalyst purification unit is located inside the injection pipe near the open end; the second catalyst purification unit is located inside the injection pipe near the closed end; the third catalyst purification unit is located inside the ventilation tower and sleeved around the injection pipe; the second catalyst purification unit and the third catalyst purification unit are cylindrical and coaxial with the injection pipe; The first catalyst purification unit is filled with a three-way catalyst; the second catalyst purification unit is filled with an oxidizing catalyst; the third catalyst purification unit is filled with a selective catalytic reduction catalyst; and the third catalyst purification unit further includes a nozzle for spraying a reducing agent onto the selective catalytic reduction catalyst.

2. The graded treatment device according to claim 1, characterized in that, The third catalyst purification unit includes multiple nozzles arranged in an array around the injection tube, with each nozzle facing the selective catalytic reduction catalyst.

3. The graded treatment device according to claim 2, characterized in that, The second catalyst purification unit includes a second frame structure, which is a cylindrical structure and coaxial with the injection pipe; The oxidized catalyst is filled on the second framework structure.

4. The graded treatment device according to claim 3, characterized in that, The third catalyst purification unit includes a third frame structure, which is a cylindrical structure and is sleeved on the outer periphery of the injection pipe, and is coaxial with the injection pipe. The selective catalytic reduction catalyst is packed on a third framework structure.

5. The graded treatment device according to claim 4, characterized in that, The first catalyst purification unit includes a first frame structure, which is an annular structure and connected to the inner wall of the injection pipe; The ternary catalyst is filled within the first frame structure.

6. The graded treatment device according to claim 5, characterized in that, The portion of the jet pipe located inside the ventilation tower has multiple ventilation holes on its peripheral side.

7. The graded treatment device according to claim 6, characterized in that, The inner wall of the end face of the closed end has a flow guide cone; The guide cone has a conical structure, with its bottom surface located on the end face and its top extending toward the opening end.

8. The graded treatment device according to claim 6, characterized in that, Multiple vent holes are evenly distributed on the peripheral surface of the injection pipe; or, The distribution density of the vent holes gradually increases along the direction from the open end to the closed end.

9. The graded treatment device according to claim 8, characterized in that, The graded treatment device also includes a storage tank for storing reducing agent, which is connected to multiple spray heads via pipelines.

10. The graded treatment device according to any one of claims 1-9, characterized in that, The catalyst resistance of the first catalyst purification unit, the second catalyst purification unit, and the third catalyst purification unit is less than or equal to 500 Pa.

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