Adjustable airflow distributor for a marine SCR system and method of distributing

Abstract

The application provides an adjustable airflow distributor for a ship SCR system, relates to the field of ship tail gas denitration treatment, and is characterized in that a variable cross-section distribution cylinder in communication with a main flue gas pipe is arranged, a gas distribution cavity is formed in the inside of the wall thickness of the variable cross-section distribution cylinder, the gas distribution cavity is separated into a plurality of flow distribution cavities arranged in sequence along an axial direction by means of a separation member, the air intake amount of each flow distribution cavity is independently adjusted by combining a plurality of electrically controlled adjusting valves, and the gas is sprayed into a main flow channel through a plurality of jet holes arranged on the inner wall surface of the variable cross-section distribution cylinder, so that the problems of uneven gas distribution in the variable cross-section transition section of the ship SCR system and the difficulty in regulating the main flue gas flow field in the prior art are solved, and the effects of improving the distribution state of the main flue gas in the main flow channel and improving the gas distribution uniformity in the variable cross-section transition section are achieved.

Description

Technical Field

[0001] This application relates to the field of marine exhaust gas denitrification technology, and in particular to an adjustable airflow distributor for marine SCR systems and its distribution method. Background Technology

[0002] Selective Catalytic Reduction (SCR) is one of the main technologies for denitrification of marine diesel engine exhaust. Marine SCR systems are typically installed in the exhaust pipe, utilizing a reducing agent to react with nitrogen oxides in the flue gas under the action of a catalyst to reduce nitrogen oxide emissions. To ensure SCR reaction efficiency, the flue gas flow field before the catalyst should be as uniform as possible; otherwise, it can easily lead to excessively high flow velocities or insufficient flow in some areas, thus affecting the reaction uniformity on the catalyst surface, resulting in decreased denitrification efficiency, increased local wear, increased ammonia slip, and shortened catalyst life.

[0003] In existing technologies, to improve the airflow distribution at the inlet of an SCR system, guide vanes, flow straighteners, porous flow equalization plates, flow divider cones, or other fixed flow equalization structures are typically installed in the flue gas passage to guide, diffuse, or redistribute the main flue gas. These solutions primarily rely on the structure itself to passively adjust the flue gas flow direction and resistance, improving the distribution of flue gas at the catalyst inlet cross-section under certain operating conditions. However, marine engine operating conditions vary significantly, with exhaust flow rate, pressure, and velocity changing markedly with load. Fixed flow equalization structures struggle to actively adjust for different operating conditions, especially in the variable cross-section transition section, where problems such as center flow deviation, insufficient gas supply to the edge regions, and uneven distribution in different areas can easily occur during flue gas flow.

[0004] Furthermore, when applied to marine SCR systems, existing technologies often struggle to meet the gas distribution needs of different regions within the variable cross-section transition section, easily leading to problems such as insufficient or excessive gas distribution in certain areas, and uneven flue gas distribution in the main duct. Especially when ship engine operating conditions vary significantly, existing fixed or integrated control structures are poorly adaptable to different airflow distributions, making it difficult to effectively regulate the intake volume in each region, thus affecting the uniformity of flue gas distribution at the catalyst inlet.

[0005] Therefore, how to provide an airflow distribution device that can adapt to changes in the operating conditions of a ship's SCR system, improve the uniformity of gas distribution in the variable cross-section transition section, and enhance the consistency of mainstream flue gas distribution has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] To address the aforementioned technical problems, this application provides an adjustable airflow distributor and its distribution method for a ship's SCR system. The method involves setting an air distribution cavity within the wall thickness of a variable cross-section distribution cylinder, and using an isolation component to divide the air distribution cavity into multiple distribution cavities arranged sequentially along the axial direction of the variable cross-section distribution cylinder. Multiple electrically controlled regulating valves are used to adjust the air intake of each distribution cavity, allowing gas to be injected into the main flow channel through jet holes opened on the inner wall of the variable cross-section distribution cylinder. This improves the distribution of the main flue gas within the main flow channel and enhances the uniformity of gas distribution within the variable cross-section transition section.

[0007] This application provides an adjustable airflow distributor and its distribution method for a ship's SCR system, which adopts the following technical solution: An adjustable airflow distributor for a ship's SCR system and its distribution method, comprising: Main flue gas pipe; A variable cross-section distribution cylinder is connected to the main flue gas pipe, and its interior defines a main flow channel for the main flue gas. Its wall thickness forms a gas distribution cavity. An ejector is disposed inside the main flue gas pipe and has an ejector gas inlet, a main flue gas inlet and a mixed gas outlet. The main flue gas inlet is connected to the interior of the main flue gas pipe. An ejector gas conduit, one end of which is connected to the ejector gas inlet, and the other end of which is connected to a compressed gas source; A gas mixture delivery pipe, one end of which is connected to the gas mixture outlet, and the other end of which is connected to the gas distribution chamber; An isolation component is disposed within the gas distribution cavity to divide the gas distribution cavity into multiple distribution cavities arranged sequentially along the axial direction of the variable cross-section distribution cylinder. Multiple electronically controlled regulating valves are used to control the air intake volume of the distribution chamber; and Multiple jet holes are formed on the inner wall surface of the variable cross-section distribution cylinder facing the main flow channel and are connected to the corresponding distribution cavity. The jet direction of the jet holes is parallel to the flow direction of the main flue gas in the main flow channel.

[0008] Furthermore, the isolation component is also used to divide each of the flow distribution chambers into multiple flow distribution sub-chambers along the circumference of the variable cross-section distribution cylinder, and the multiple flow distribution sub-chambers are arranged sequentially along the circumference of the variable cross-section distribution cylinder, and the jet hole is connected to the corresponding flow distribution sub-chamber.

[0009] Furthermore, the isolation component includes multiple first partitions and multiple sets of second partitions. The multiple first partitions are spaced apart along the axial direction of the variable cross-section distribution cylinder to divide the gas distribution cavity into multiple distribution cavities arranged sequentially along the axial direction. The multiple sets of second partitions are respectively disposed in each distribution cavity. Each set of second partitions includes two second partitions extending along the main flue gas flow direction and spaced apart circumferentially along the variable cross-section distribution cylinder. A gas distribution channel is formed between two second partitions in the same set, and a distribution sub-cavity is formed between two adjacent sets of second partitions, so that each distribution cavity is divided into multiple distribution sub-cavities circumferentially.

[0010] Furthermore, the isolation component also includes multiple third partitions, each of which is disposed between two second partitions in a corresponding group and is arranged parallel to the second partitions to symmetrically divide the gas distribution channel into a first channel and a second channel. The first channel is connected to a flow distribution chamber on one side of the gas distribution channel, and the second channel is connected to a flow distribution chamber on the other side of the gas distribution channel. The number of the mixed gas delivery pipes is the same as the total number of the first channel and the second channel, and each pipe is configured to correspond one-to-one with a plurality of the first channel and the second channel. One end of each mixed gas delivery pipe is connected to the mixed gas outlet of the ejector, and the other end is connected to the corresponding first channel or the second channel.

[0011] Furthermore, each of the flow distribution chambers is provided with an electronically controlled regulating valve on both sides of its circumference. The outlet of each electronically controlled regulating valve is connected to the corresponding flow distribution chamber. The inlets of the two electronically controlled regulating valves are respectively connected to a first channel or a second channel located on both sides of the flow distribution chamber and belonging to two adjacent air distribution channels.

[0012] Furthermore, the variable cross-section distribution cylinder is a four-sided variable cross-section cylinder, and the gas distribution cavity is provided with four flow distribution chambers, which are respectively distributed in the four corner regions of the four-sided variable cross-section cylinder; a fourth partition is also provided at each corner of the four-sided variable cross-section cylinder, the fourth partition is arranged along the extension direction of the corresponding corner, and divides the flow distribution chamber located in the corresponding corner region into two sub-cavities that extend along the two side walls of the corner respectively.

[0013] Furthermore, the electrically controlled regulating valve is a butterfly valve, and the driving part of the electrically controlled regulating valve is located outside the variable cross-section distribution cylinder. The driving part and the valve body are connected by a control shaft that passes through the wall thickness of the variable cross-section distribution cylinder.

[0014] Furthermore, each of the flow distribution chambers has at least one row of jet holes on its inner wall, the jet holes in the same flow distribution chamber are arranged in a spiral shape, and the diameter and arrangement density of the jet holes in different flow distribution chambers are the same.

[0015] Furthermore, the ejector is coaxially arranged with the main flue gas pipe, the ejector gas duct is arranged radially along the main flue gas pipe, and a conical guide tube is provided at the ejector gas inlet. The large-diameter end of the conical guide tube is arranged facing away from the inside of the ejector, and the small-diameter end is arranged facing the inside of the ejector. The exhaust port of the ejector gas duct is arranged facing the outer wall of the conical guide tube, so that the gas discharged from the ejector gas duct is guided along the outer wall of the conical guide tube into the inside of the ejector.

[0016] This application also provides an adjustable airflow distributor for a ship's SCR system and its distribution method, which includes the following steps: S1, Injector gas mixing step: The compressed gas output from the compressed gas source is introduced into the ejector through the ejector gas conduit, and the ejector injects the main flue gas in the main flue gas pipe to form a mixed gas; S2, Gas delivery and distribution steps: The mixed gas enters the gas distribution cavity inside the variable cross-section distribution cylinder wall through the mixed gas delivery pipe, and is delivered to multiple distribution cavities respectively; S3. Adjustment and distribution steps: The gas flow rate entering each of the distribution chambers is adjusted by multiple electronically controlled regulating valves, so that the gas enters each of the distribution chambers respectively; S4. Jet distribution step: The gas in each of the distribution chambers is injected into the main flow channel through the corresponding jet holes to adjust the flow distribution of the main flue gas in the main flow channel.

[0017] In summary, this application includes at least one of the following beneficial technical effects: 1. This application solves the problems of uneven gas distribution and difficulty in controlling the main flue gas flow field in the variable cross-section transition section of the ship's SCR system by setting a variable cross-section distribution cylinder connected to the main flue gas pipe, forming a gas distribution cavity inside the wall of the variable cross-section distribution cylinder, and using isolation components to divide the gas distribution cavity into multiple distribution cavities arranged sequentially along the axial direction. At the same time, multiple electronically controlled regulating valves are used to independently adjust the air intake of each distribution cavity. Then, gas is injected into the main flow channel through multiple jet holes opened on the inner wall of the variable cross-section distribution cylinder. This solves the problems of uneven gas distribution and difficulty in controlling the main flue gas flow field in the variable cross-section transition section of the ship's SCR system in the prior art, thereby improving the main flue gas flow. The distribution pattern within the main flue gas duct improves the uniformity of gas distribution within the variable cross-section transition section. The ejector uses high-pressure gas to eject the main flue gas, driving it through quickly and increasing its flow rate, thus providing a stable gas source for subsequent zoned gas distribution. The electronically controlled regulating valve can compensate and adjust the intake volume according to the gas distribution needs of different areas. When the gas flow rate in the main pipe section is low, the intake volume of the corresponding distribution chamber on the side closest to the main flue gas pipe can be reduced or closed, allowing more of the limited gas volume to be distributed to other areas, thereby further improving the overall uniformity of gas distribution. 2. This application further divides each distribution chamber into multiple distribution sub-chambers along the circumference and forms gas distribution channels between the same group through a second baffle, so that each distribution sub-chamber can be arranged sequentially along the circumference of the variable cross-section distribution cylinder. This solves the problem of large gas distribution range in a single area and difficulty in fine adjustment in local areas in the prior art, and achieves the effect of further subdividing the gas distribution at different positions in the circumference and improving the gas distribution adjustment accuracy and distribution balance in different areas. 3. This application solves the problems of limited single-sided gas supply regulation capacity and insufficient gas compensation in adjacent areas in the prior art by setting a third baffle in the gas distribution channel, and setting an electrically controlled regulating valve on both sides of the circumference of each distribution chamber, so that the distribution chamber can be connected to different channels on both sides respectively. This achieves the effect of enhancing the flexibility of gas intake regulation in each distribution chamber and improving the stability and uniformity of gas distribution in local areas. In particular, under different working conditions, the dual-sided gas supply regulation of the corresponding distribution chamber can be achieved by the difference in the opening of the electrically controlled regulating valves on both sides, which is more conducive to balancing the gas flow at different positions of the variable cross-section distribution cylinder. 4. This application solves the problems of poor airflow distribution adaptability and insufficient regulation response under different working conditions in the prior art by setting the variable cross-section distribution cylinder as a four-sided variable cross-section cylinder, and combining it with a butterfly valve-type electrically controlled regulating valve and a spirally arranged jet orifice structure. At the same time, the gas flow rate entering each distribution cavity is adjusted by controlling the opening degree of each electrically controlled regulating valve in the distribution method. This achieves the effects of regular structural layout, convenient zone control, enhanced jet disturbance and diffusion capabilities, and improved system adaptability to changes in working conditions. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the overall structure of the adjustable airflow distributor for a ship SCR system according to the present invention.

[0020] Figure 2 This is a schematic diagram of the internal structure of the adjustable airflow distributor for a ship SCR system according to the present invention.

[0021] Figure 3 This is a schematic diagram of the ejector of the adjustable airflow distributor for a ship SCR system according to the present invention.

[0022] Figure 4This is a schematic diagram of the layout of the isolation component of the adjustable airflow distributor for a ship SCR system according to the present invention.

[0023] Figure 5 yes Figure 2 Enlarged view of part A in the middle.

[0024] Figure 6 This is a schematic diagram of the working process of the adjustable airflow distributor for a ship SCR system according to the present invention.

[0025] Reference numerals in the attached drawings: 1. Main flue gas pipe; 2. Variable cross-section distribution cylinder; 3. Ejector; 31. Ejector gas inlet; 32. Main flue gas inlet; 33. Mixed gas outlet; 34. Conical guide cylinder; 4. Ejector gas duct; 5. Mixed gas delivery pipe; 6. Isolation component; 61. First baffle; 62. Second baffle; 63. Third baffle; 64. Fourth baffle; 7. Electrically controlled regulating valve; 8. Jet orifice; 9. Distribution chamber; 10. Gas distribution channel; 11. First channel; 12. Second channel. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0027] This application discloses an adjustable airflow distributor for a ship's SCR system and its distribution method. (Refer to...) Figures 1 to 6 The adjustable airflow distributor comprises a main flue gas pipe 1, a variable cross-section distribution cylinder 2, an ejector 3, an ejector gas duct 4, a mixed gas delivery pipe 5, an isolation component 6, an electrically controlled regulating valve 7, and a jet orifice 8. The main flue gas pipe 1 allows the main flue gas to pass through axially. The variable cross-section distribution cylinder 2 is connected to the main flue gas pipe 1 and located downstream of it. The ejector 3 is located inside the main flue gas pipe 1. The ejector gas duct 4 is connected to the ejector 3 to introduce compressed gas into it. The mixed gas delivery pipe 5 is connected to the ejector 3 to deliver the mixed gas formed by the ejector 3 to the variable cross-section distribution cylinder 2. The isolation component 6 is located within the wall of the variable cross-section distribution cylinder 2 to form multiple chambers for zoned gas distribution. The electrically controlled regulating valve 7 adjusts the air intake volume for each zone. The jet orifice 8 directs the gas from each zone into the main flow channel of the variable cross-section distribution cylinder 2, thereby achieving active control of the main flue gas flow field.

[0028] Specifically, such as Figure 1As shown, the main flue gas pipe 1 is preferably a cylindrical straight pipe section with a hollow cylindrical structure throughout its wall, facilitating connection with the upstream exhaust pipe of the ship's SCR system. The main flue gas pipe 1 can be made of heat-resistant metal fittings, with one end fixedly connected to the upstream flue and the other end connected to the small end of the variable cross-section distribution cylinder 2. In this embodiment, the main flue gas pipe 1 and the variable cross-section distribution cylinder 2 can be connected by flange sealing, welding, or other fixed connection methods that meet the sealing requirements for high-temperature flue gas transportation. Thus, the main flue gas can stably enter the variable cross-section distribution cylinder 2 along the axial direction of the main flue gas pipe 1, providing a basic fluid channel for subsequent flow field adjustment.

[0029] Furthermore, such as Figure 2 As shown, the variable cross-section distribution cylinder 2 has an overall variable cross-section cylindrical structure that gradually expands from the small end to the large end. Its interior defines a main flow channel for the main flue gas, and its wall thickness forms gas distribution cavities arranged around the main flow channel. To balance structural regularity and convenient zoning, in this embodiment, the variable cross-section distribution cylinder 2 is preferably a four-sided variable cross-section cylinder with four side walls connected sequentially along the circumference. Each side wall can be integrally flat or slightly arc-shaped, with its inner side collectively forming the main flow channel and its outer side collectively defining the outer contour of the variable cross-section distribution cylinder 2. Furthermore, each side wall has a certain wall thickness, and a hollow interlayer region is formed between the inner and outer wall surfaces of the side walls. The hollow interlayer regions of the four side walls are independent or interconnected to form the gas distribution cavities. Preferably, the small end of the variable cross-section distribution cylinder 2 is connected to the main flue gas pipe 1, and the large end is used to connect to the inlet section of the SCR reactor, thus balancing the expansion of the main flow channel and the gas distribution within the wall thickness when the main flue gas enters the larger cross-section region from a circular or near-circular flue.

[0030] To facilitate understanding of the internal structure of the aforementioned wall thickness, the variable cross-section distribution cylinder 2 can be understood as a hollow polygonal variable cross-section cylinder formed by the inner and outer walls. The inner wall directly defines the main flow channel, while a gas distribution cavity is formed between the outer and inner walls. With this configuration, the main flue gas flows primarily within the main flow channel, while the mixed gas used to regulate the flow field is mainly distributed and transported within the gas distribution cavity inside the wall thickness, finally entering the main flow channel through the jet holes 8. Thus, the gas distribution within the wall thickness is separated from the central main flow transport, avoiding significant occupation of the main flow channel cross-sectional area and facilitating zoned regulation of different areas.

[0031] Furthermore, such as Figure 2 and Figure 3As shown, the ejector 3 is disposed inside the main flue gas pipe 1 and is preferably coaxially arranged with the main flue gas pipe 1. The ejector 3 can be an axially penetrating cylindrical ejector, and its interior forms a flow channel connecting the main flue gas inlet 32 ​​to the mixed gas outlet 33. The main flue gas inlet 32 ​​is arranged facing the upstream side of the main flue gas pipe 1, so that the main flue gas can enter the ejector 3 along the axial direction of the ejector 3; the mixed gas outlet 33 is arranged facing the downstream side of the main flue gas pipe 1, so as to send out the mixed gas formed after ejection.

[0032] To improve the guiding effect of the ejector gas entering the ejector 3, a conical guide tube 34 is provided at the ejector gas inlet 31 of the ejector 3. The conical guide tube 34 is a hollow cone, with its large-diameter end facing away from the interior of the ejector 3 and its small-diameter end facing the interior of the ejector 3. The ejector gas duct 4 is arranged radially along the main flue gas pipe 1, with its exhaust port facing the outer wall of the conical guide tube 34, so that the compressed gas discharged from the ejector gas duct 4 can be guided along the outer wall of the conical guide tube 34 into the interior of the ejector 3. In this way, on the one hand, the local impact and turbulence when the compressed gas enters the ejector 3 can be reduced, and on the other hand, it is also beneficial to improve the mixing efficiency between the ejector gas and the main flue gas.

[0033] Specifically, the ejector gas duct 4 can be a tubular guide component, with one end connected to the ejector gas inlet 31 of the ejector 3 and the other end connected to a compressed gas source. The ejector gas duct 4 is preferably radially inserted into the wall of the main flue gas pipe 1 and fixedly connected to it. To ensure sealing during high-pressure gas introduction, the ejector gas duct 4 and the main flue gas pipe 1 are preferably connected by welding, flange sealing, or sleeve sealing. Furthermore, the gas introduced by the ejector gas duct 4 can be compressed air, high-pressure inert gas, or other compressed gas suitable for ejection mixing. In a preferred embodiment, a high-temperature, high-pressure gas matching the operating conditions of the ship's engine can also be used to increase the flow rate and temperature of the mixed gas.

[0034] Furthermore, the mixed gas delivery pipe 5 can be a completely sealed tubular component, with one end connected to the mixed gas outlet 33 of the ejector 3 and the other end connected to the gas distribution cavity inside the wall of the variable cross-section distribution cylinder 2. Preferably, the mixed gas delivery pipe 5 is led out from the downstream side of the main flue gas pipe 1 and is fixedly connected to the hollow area of ​​the wall of the variable cross-section distribution cylinder 2, thereby directly delivering the mixed gas formed by the ejector 3 to the inside of the gas distribution cavity. To reduce the delivery resistance, the mixed gas delivery pipe 5 can preferably be a circular or near-circular cross-section pipe, and its pipe routing can be connected by a straight line, a broken line, or an arc according to the installation position of the variable cross-section distribution cylinder 2.

[0035] Therefore, the mixed gas can stably enter the gas distribution area inside the wall thickness without first entering the main channel and then being secondary distributed.

[0036] Furthermore, such as Figure 4As shown, the isolation component 6 is disposed inside the gas distribution cavity to divide the gas distribution cavity into multiple distribution cavities arranged sequentially along the axial direction of the variable cross-section distribution cylinder 2. Specifically, the isolation component 6 includes multiple first partition plates 61. The first partition plate 61 is preferably a frame-shaped or annular plate that fits the inner and outer contours of the variable cross-section distribution cylinder 2. Its outer peripheral edge is fixedly connected to the outer wall of the variable cross-section distribution cylinder 2, and its inner peripheral edge is fixedly connected to the inner wall of the variable cross-section distribution cylinder 2. The multiple first partition plates 61 are spaced apart along the axial direction of the variable cross-section distribution cylinder 2, and the space between two adjacent first partition plates 61 and the inner and outer walls of the corresponding side walls together form a distribution cavity. Since the first partition plates 61 are spaced apart along the axial direction, the multiple distribution cavities are arranged sequentially along the length direction of the variable cross-section distribution cylinder 2. With this arrangement, the originally continuous internal gas distribution space can be divided into multiple axially independent regions, thereby facilitating gas distribution adjustment according to axial position.

[0037] Furthermore, to achieve more precise circumferential distribution within each distribution cavity, the isolation member 6 also includes multiple sets of second baffles 62. The second baffles 62 are preferably elongated strip-shaped baffles, extending in the same direction as the main flue gas flow, and are spaced apart circumferentially within each distribution cavity along the variable cross-section distribution cylinder 2. Preferably, each set of second baffles 62 includes two parallel second baffles 62, forming a gas distribution channel 10 between the two second baffles 62 in the same set, and forming a distribution sub-cavity 9 between adjacent sets of second baffles 62, so that each distribution cavity is divided into multiple distribution sub-cavities 9 circumferentially. Further, both ends of the second baffle 62 are fixedly connected to adjacent first baffles 61, the side closer to the main flow channel is fixedly connected to the inner wall of the variable cross-section distribution cylinder 2, and the side farther from the main flow channel is fixedly connected to the outer wall of the variable cross-section distribution cylinder 2. Thus, each set of second partitions 62, together with the inner wall, the outer wall, and the two first partitions 61, forms a strip-shaped gas distribution channel 10, while the adjacent sets of second partitions 62 form corresponding flow distribution chambers 9.

[0038] To further improve the uniformity of gas supply from the gas distribution channel 10 to the two distribution chambers 9, the isolation component 6 also includes multiple third partitions 63. Each third partition 63 is disposed between two second partitions 62 in a corresponding group and is arranged parallel to the second partitions 62. Preferably, the third partition 63 is also a long strip-shaped partition, with its two ends connected to the adjacent first partition 61, its inner side connected to the inner wall of the variable cross-section distribution cylinder 2, and its outer side connected to the outer wall of the variable cross-section distribution cylinder 2. Thus, the third partition 63 can symmetrically divide the gas distribution channel 10 into a first channel 11 and a second channel 12, wherein the first channel 11 is connected to the distribution chamber 9 on one side of the gas distribution channel 10, and the second channel 12 is connected to the distribution chamber 9 on the other side of the gas distribution channel 10. Through this symmetrical separation, a gas distribution channel 10 can provide gas passages from both sides to two adjacent distribution chambers 9, creating conditions for subsequent dual-sided air intake adjustment.

[0039] Furthermore, in this embodiment, the mixed gas delivery pipe 5 is preferably configured as multiple pipes, the number of which is consistent with the total number of the first channel 11 and the second channel 12, and is configured in a one-to-one correspondence with the multiple first channels 11 and the second channels 12. Specifically, each mixed gas delivery pipe 5 can be an independent tubular delivery branch, with one end connected to the mixed gas outlet 33 of the ejector 3 and the other end connected to the corresponding first channel 11 or second channel 12, thereby introducing the mixed gas formed by the ejector 3 into each first channel 11 and second channel 12 respectively. Thus, the mixed gas can enter the channel structure at different positions along multiple independent delivery paths, avoiding cross-flow or local interference between multiple gas streams before entering each first channel 11 and second channel 12, and facilitating subsequent fine adjustment of the air intake of each distribution chamber 9 by the electronically controlled regulating valve 7, thereby improving the uniformity of the overall gas distribution and the flexibility of control.

[0040] In this embodiment, the variable cross-section distribution cylinder 2 is preferably a four-sided variable cross-section cylinder, with four distribution chambers respectively located at the four corner regions of the cylinder. Since the four-sided variable cross-section cylinder has bends at its corners, to avoid the distribution chambers forming bent flow channels in the bend areas and to further improve the smoothness and uniformity of gas delivery in each region, a fourth baffle 64 is preferably provided at each corner of the cylinder. The fourth baffle 64 can extend along the length direction of the corresponding corner and connect to the inner surface of the adjacent wall thickness, thereby dividing the distribution chamber that originally spanned the corner region into two distribution chambers that extend smoothly along adjacent sidewalls. This reduces flow disturbance and local resistance at the corner bends, lowers the possibility of local accumulation or flow deviation, and thus helps to further improve the overall uniformity of airflow distribution within the variable cross-section distribution cylinder 2.

[0041] In addition, each distribution chamber 9 is equipped with an electrically controlled regulating valve 7 on both sides of its circumference. The electrically controlled regulating valve 7 is preferably a butterfly valve, with its valve body located at the corresponding connection port. The valve plate can rotate within the valve body to adjust the flow cross-sectional area. The outlet of each electrically controlled regulating valve 7 is connected to the corresponding distribution chamber 9, and the inlets of the two electrically controlled regulating valves 7 are respectively connected to a first channel 11 or a second channel 12 located on both sides of the distribution chamber 9 and belonging to two adjacent gas distribution channels 10. In other words, a distribution chamber 9 does not only receive gas from one side, but can obtain gas from the two corresponding half-channels on its circumference. Thus, under different operating conditions, the same distribution chamber 9 can be adjusted by adjusting the opening degree of the electrically controlled regulating valves 7 on both sides, which is more conducive to balancing the gas flow at different circumferential positions. Furthermore, when the gas flow rate in the main pipe section is low, the opening of the corresponding electronically controlled regulating valve 7 on the side near the main flue gas pipe 1 can be reduced or closed, so that the limited gas volume can be distributed to other areas, thereby improving the overall gas distribution uniformity.

[0042] Furthermore, the drive unit of the electrically controlled regulating valve 7 is located outside the variable cross-section distribution cylinder 2, and the drive unit is connected to the valve body via a control shaft that passes through the wall thickness of the variable cross-section distribution cylinder 2. The drive unit can be a motor, a reduction gear, or an actuator assembly, preferably a stepper motor or a servo motor. The control shaft is preferably a rod-shaped transmission component, with one end connected to the drive unit and the other end connected to the butterfly valve plate, thereby transmitting the rotational motion of the drive unit to the interior of the valve body. To ensure sealing at the point where the control shaft passes through the wall thickness of the variable cross-section distribution cylinder 2, a sealing element or sealing sleeve is preferably provided at the location where the control shaft passes through the wall thickness of the variable cross-section distribution cylinder 2. This arrangement allows for precise control of the valve opening and prevents leakage of flue gas or mixed gas.

[0043] Additionally, the jet orifice 8 is formed on the inner wall of the variable cross-section distribution cylinder 2 facing the main flow channel and is connected to the corresponding distribution cavity 9. Specifically, as shown... Figure 2 and Figure 5 As shown, each distribution chamber 9 preferably has at least one row of jet holes 8 on its inner wall, and the jet holes 8 in the same distribution chamber 9 are arranged in a spiral pattern. The jet holes 8 are preferably circular holes, and the axial direction of each jet hole 8 is parallel to the flow direction of the main flue gas in the main flow channel. The diameter and arrangement density of the jet holes 8 in different distribution chambers 9 are the same. Thus, the gas in each distribution chamber 9 can be directionally injected into the main flow channel along the flow direction of the main flue gas. On the one hand, this reduces the angle of attack impact with the main flue gas, and on the other hand, the multi-row, spirally distributed jet holes 8 improve the local disturbance and diffusion effect, thereby improving the consistency of flue gas distribution in the main flow channel without significantly increasing the main flow resistance.

[0044] In this embodiment, refer to Figures 1 to 5 When the main flue gas enters the ejector 3 through the main flue gas pipe 1, the compressed gas output from the compressed gas source is simultaneously introduced into the ejector gas inlet 31 of the ejector 3 through the ejector gas conduit 4. Since the exhaust port of the ejector gas conduit 4 is set towards the outer wall of the conical guide cylinder 34, the compressed gas is guided along the outer wall of the conical guide cylinder 34 into the interior of the ejector 3, and mixes with the main flue gas from the main flue gas inlet 32 ​​inside the ejector 3 to form a mixed gas with a higher flow rate. The mixed gas then enters the gas distribution chamber inside the wall thickness of the variable cross-section distribution cylinder 2 through the mixed gas delivery pipe 5, and enters multiple distribution chambers along the axial direction. Further, the mixed gas is then delivered to the electrically controlled regulating valves 7 at different positions through each gas distribution channel 10, the first channel 11 and the second channel 12, and enters the corresponding distribution chamber 9 under the control of the opening degree of the electrically controlled regulating valve 7. Finally, it is injected into the main flow channel through the jet hole 8 to regulate the flow distribution of the main flue gas in the main flow channel. Therefore, this application achieves active homogenization of the main flue gas flow field within the variable cross-section transition section of the ship's SCR system through the path of "ejector mixing - wall thickness distribution - zoned valve control - directional jet".

[0045] On the other hand, the allocation method of this application embodiment includes the following steps: S1. High-pressure gas output from the compressed gas source is introduced into the ejector gas inlet 31 of the ejector 3 through the ejector gas conduit 4. Simultaneously, the main flue gas in the main flue gas pipe 1 enters the ejector 3 through the main flue gas inlet 32. The ejector 3 uses high-pressure gas to eject the main flue gas, causing it to pass through the ejector 3 quickly, thereby increasing the flow rate of the main flue gas. Preferably, after a conical guide tube 34 is provided at the ejector gas inlet 31, the high-pressure gas discharged from the ejector gas conduit 4 can be guided along the outer wall of the conical guide tube 34 into the ejector 3, thereby improving the stability of the high-pressure gas entering the ejector 3.

[0046] S2. Gas delivery and distribution step. The mixed gas is delivered to multiple distribution channels via the mixed gas delivery pipe 5. Specifically, after the mixed gas is output from the mixed gas outlet 33 of the ejector 3, it enters the corresponding distribution channels through multiple mixed gas delivery pipes 5, which are arranged one-to-one with each of the first channel 11 and the second channel 12, thereby completing the branched delivery of the mixed gas along different regions. Thus, the mixed gas is directionally distributed to different distribution channels before entering each distribution chamber 9.

[0047] S3. Adjustment and Distribution Steps. Multiple electrically controlled regulating valves 7 are used to adjust the gas flow rate entering each distribution chamber 9 from each distribution channel, ensuring that the gas enters each distribution chamber 9 within its corresponding distribution chamber. Specifically, each distribution chamber 9 has an electrically controlled regulating valve 7 on both sides of its circumference. The inlets of the two electrically controlled regulating valves 7 are connected to the first channel 11 or the second channel 12 located on either side of the distribution chamber 9, and their outlets are connected to the corresponding distribution chamber 9. Therefore, the same distribution chamber 9 can receive gas from both sides of its circumference. Furthermore, each electrically controlled regulating valve 7 can be adjusted synchronously or independently according to different operating conditions to change the gas flow distribution state in different areas. When the gas flow rate in the main pipe section is low, the opening of the electrically controlled regulating valve 7 in the corresponding area near the main flue gas pipe 1 can be reduced or closed to distribute more of the limited gas volume to other areas.

[0048] S4. Jet Distribution Step. Gas from each distribution chamber 9 is injected into the main flow channel through corresponding jet holes 8 to regulate the flow distribution of the main flue gas within the main flow channel. Since the jet holes 8 are located on the inner wall of the variable cross-section distribution cylinder 2 facing the main flow channel, and the injection direction of the jet holes 8 is parallel to the flow direction of the main flue gas within the main flow channel, the gas ejected from each distribution chamber 9 can enter the main flow channel along the main flow direction, compensating for and adjusting the flue gas flow rate and velocity distribution at different locations within the main flow channel, thereby improving the uniformity of gas distribution within the variable cross-section transition section. Preferably, when the jet holes 8 within the same distribution chamber 9 are arranged in a spiral pattern, it is more conducive to enhancing local disturbance and diffusion effects.

[0049] Thus, through continuous control from S1 to S4, this embodiment realizes a complete control process from compressed gas injection mixing, multi-region delivery within the wall thickness, dual-side zoned valve control to directional jet compensation, thereby improving the uniformity of gas distribution in the variable cross-section transition section and enhancing the consistency of the main flue gas flow distribution before the catalyst inlet.

[0050] During use, combined Figure 6 As shown, the system-level workflow of this embodiment includes: a high-temperature, high-pressure gas branch output from the diesel engine side; the main flue gas, after being mixed at the front end, enters the adjustable gas flow distributor and then the catalytic reactor; simultaneously, sensors at different locations at the rear end of the catalytic reactor feed back flow signals to the controller, which outputs valve electrical signals to the adjustable gas flow distributor to adjust the opening of each electronically controlled regulating valve 7. Thus, this embodiment achieves dynamic adjustment of the main flue gas flow field before entering the catalytic reactor through the process of "injected mixing—channel delivery—valve-controlled distribution—jet supplementation".

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An adjustable airflow distributor for a ship's SCR system, characterized in that, include: Main flue gas pipe; A variable cross-section distribution cylinder is connected to the main flue gas pipe, and its interior defines a main flow channel for the main flue gas. Its wall thickness forms a gas distribution cavity. An ejector is disposed inside the main flue gas pipe and has an ejector gas inlet, a main flue gas inlet and a mixed gas outlet. The main flue gas inlet is connected to the interior of the main flue gas pipe. An ejector gas conduit, one end of which is connected to the ejector gas inlet, and the other end of which is connected to a compressed gas source; A gas mixture delivery pipe, one end of which is connected to the gas mixture outlet, and the other end of which is connected to the gas distribution chamber; An isolation component is disposed within the gas distribution cavity to divide the gas distribution cavity into multiple distribution cavities arranged sequentially along the axial direction of the variable cross-section distribution cylinder. Multiple electronically controlled regulating valves are used to control the air intake volume of the distribution chamber; as well as Multiple jet holes are formed on the inner wall surface of the variable cross-section distribution cylinder facing the main flow channel and are connected to the corresponding distribution cavity. The jet direction of the jet holes is parallel to the flow direction of the main flue gas in the main flow channel.

2. The adjustable airflow distributor and its distribution method for a ship SCR system according to claim 1, characterized in that, The isolation component is also used to divide each of the flow distribution chambers into multiple flow distribution sub-chambers along the circumference of the variable cross-section distribution cylinder. The multiple flow distribution sub-chambers are arranged sequentially along the circumference of the variable cross-section distribution cylinder, and the jet hole is connected to the corresponding flow distribution sub-chamber.

3. The adjustable airflow distributor and its distribution method for a ship SCR system according to claim 2, characterized in that, The isolation component includes multiple first partitions and multiple sets of second partitions. The multiple first partitions are spaced apart along the axial direction of the variable cross-section distribution cylinder to divide the gas distribution cavity into multiple distribution cavities arranged sequentially along the axial direction. The multiple sets of second partitions are respectively disposed in each distribution cavity. Each set of second partitions includes two second partitions extending along the main flue gas flow direction and spaced apart circumferentially along the variable cross-section distribution cylinder. A gas distribution channel is formed between two second partitions in the same set, and a distribution sub-cavity is formed between two adjacent sets of second partitions, so that each distribution cavity is divided into multiple distribution sub-cavities circumferentially.

4. The adjustable airflow distributor and its distribution method for a ship SCR system according to claim 3, characterized in that, The isolation component also includes multiple third partitions, each of which is disposed between two second partitions in a corresponding group and is arranged parallel to the second partitions to symmetrically divide the gas distribution channel into a first channel and a second channel. The first channel is connected to a flow distribution chamber on one side of the gas distribution channel, and the second channel is connected to a flow distribution chamber on the other side of the gas distribution channel. The number of the mixed gas delivery pipes is the same as the total number of the first channel and the second channel, and each pipe is configured to correspond one-to-one with a plurality of the first channel and the second channel. One end of each mixed gas delivery pipe is connected to the mixed gas outlet of the ejector, and the other end is connected to the corresponding first channel or the second channel.

5. An adjustable airflow distributor for a ship's SCR system and its distribution method according to claim 4, characterized in that, Each of the flow distribution chambers is provided with an electronically controlled regulating valve on both sides of its circumference. The outlet of each electronically controlled regulating valve is connected to the corresponding flow distribution chamber. The inlets of the two electronically controlled regulating valves are connected to a first channel or a second channel located on both sides of the flow distribution chamber and belonging to two adjacent air distribution channels.

6. An adjustable airflow distributor for a ship's SCR system and its distribution method according to claim 4, characterized in that, The variable cross-section distribution cylinder is a four-sided variable cross-section cylinder. The gas distribution cavity is provided with four flow distribution chambers, which are respectively distributed in the four corner regions of the four-sided variable cross-section cylinder. A fourth partition is also provided at each corner of the four-sided variable cross-section cylinder. The fourth partition is arranged along the extension direction of the corresponding corner and divides the flow distribution chamber located in the corresponding corner region into two sub-cavities that extend along the two side walls of the corner respectively.

7. An adjustable airflow distributor for a ship's SCR system and its distribution method according to claim 1, characterized in that, The electrically controlled regulating valve is a butterfly valve. The drive unit of the electrically controlled regulating valve is located outside the variable cross-section distribution cylinder. The drive unit and the valve body are connected by a control shaft that passes through the wall thickness of the variable cross-section distribution cylinder.

8. An adjustable airflow distributor for a ship's SCR system and its distribution method according to claim 1, characterized in that, Each of the flow distribution chambers has at least one row of jet holes on its inner wall. The jet holes in the same flow distribution chamber are arranged in a spiral shape, and the diameter and arrangement density of the jet holes in different flow distribution chambers are the same.

9. An adjustable airflow distributor for a ship's SCR system and its distribution method according to claim 1, characterized in that, The ejector is coaxially arranged with the main flue gas pipe, the ejector gas duct is arranged radially along the main flue gas pipe, and a conical guide tube is provided at the ejector gas inlet. The large-diameter end of the conical guide tube is arranged facing away from the inside of the ejector, and the small-diameter end is arranged facing the inside of the ejector. The exhaust port of the ejector gas duct is arranged facing the outer wall of the conical guide tube, so that the gas discharged from the ejector gas duct is guided along the outer wall of the conical guide tube into the inside of the ejector.

10. A distribution method for an adjustable airflow distributor for a ship's SCR system based on any one of claims 1-9, characterized in that, Includes the following steps: S1, Injector gas mixing step: The compressed gas output from the compressed gas source is introduced into the ejector through the ejector gas conduit, and the ejector injects the main flue gas in the main flue gas pipe to form a mixed gas; S2, Gas delivery and distribution steps: The mixed gas enters the gas distribution cavity inside the variable cross-section distribution cylinder wall through the mixed gas delivery pipe, and is delivered to multiple distribution cavities respectively; S3. Adjustment and distribution steps: The gas flow rate entering each of the distribution chambers is adjusted by multiple electronically controlled regulating valves, so that the gas enters each of the distribution chambers respectively; S4. Jet distribution step: The gas in each of the distribution chambers is injected into the main flow channel through the corresponding jet holes to adjust the flow distribution of the main flue gas in the main flow channel.

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