SCR (Selective Catalytic Reduction) catalytic silencer

Abstract

The utility model provides an SCR (Selective Catalytic Reduction) catalytic silencer. Comprising a shell, the two sides of the shell are communicated with a gas inlet pipe and a gas outlet pipe respectively, a catalyst carrier layer is installed in the shell, the SCR catalytic silencer further comprises a gas mixing device, and the gas mixing device comprises a first partition plate installed between the gas inlet pipe and the catalyst carrier layer, and rotational flow holes are formed in the peripheral side of the first partition plate; and the second partition plate is arranged between the first partition plate and the catalyst carrier layer. The perforated pipe is arranged between the first partition plate and the second partition plate and comprises a necking part, a throat part and an expansion part which are connected in sequence, and silencing holes are formed in the throat part. According to the SCR catalytic silencer, airflow of the rotational flow holes in the first partition plate collides with airflow from the silencing holes, strong disturbance is generated, the turbulence intensity is increased, crushing and decomposition of urea water solution liquid drops are facilitated, mixing of urea and tail gas is accelerated, urea crystallization is avoided, meanwhile, a silencing result is set, and the service life of the SCR catalytic silencer is prolonged. And noise reduction is carried out on the device.

Description

Technical Field

[0001] The utility model relates to the technical field of catalytic mufflers, in particular to an SCR catalytic muffler. Background Art

[0002] NOx is one of the main harmful emissions from marine diesel engines, causing serious harm to the environment and human health. In September 1997, IMO (International Maritime Organization) adopted the 1997 Protocol to the MARPOL 73 / 78 Convention, and added Annex VI "Regulations for the Prevention of Air Pollution from Ships", which came into effect in my country on August 23, 2006. In October 2008, IMO formally adopted the amendment to Annex VI of MARPOL 73 / 78 "NOx X Technical Regulations, for NO X The emission limits for marine engines are set at three levels. X Emissions have become an important topic in preventing air pollution from ships.

[0003] Generally, marine diesel engines can achieve the first and second stage emission requirements with the help of in-engine purification technology, but the third stage requires about 75% NOx reduction on the basis of the second stage. X To reduce the NO, it is difficult to meet the requirements by relying on in-machine purification alone, and the application of external control technology is inevitable. X High conversion efficiency, good fuel economy and wide application range have become the advantages of foreign control ship engine NO X The main emission options.

[0004] Patent No. CN111894610A discloses a marine diesel engine exhaust SCR denitrification purification muffler, including a guide device, an SCR reduction device, and a muffler. The SCR reduction device uses a two-stage catalyst, and there is no mixer at the front end of the SCR. The mixing uniformity of exhaust gas and urea is not considered, which affects NO X conversion rate.

[0005] Patent No. CN113230840A discloses a low-temperature plasma-coordinated SCR exhaust gas treatment device, which includes a low-temperature plasma module and an SCR reaction module. However, the SCR reaction module in the device is not equipped with a muffler, and the noise cannot be effectively controlled.

[0006] Therefore, in view of the above problems, the present application proposes an SCR catalytic muffler. Utility Model Content

[0007] In view of the above problems, the utility model provides an SCR catalytic muffler, in which the airflow through the swirl holes on the first partition plate collides with the airflow from the muffler holes, generating strong disturbances, increasing the turbulence intensity, being beneficial to the breakup and decomposition of urea aqueous solution droplets, accelerating the mixing of urea and exhaust gas, avoiding the formation of urea crystals, and at the same time setting a muffler effect to muffle and reduce noise of the device.

[0008] An SCR catalytic silencer comprises a shell, wherein both sides of the shell are connected with an air inlet pipe and an air outlet pipe respectively, and a catalyst carrier layer is installed in the shell. The SCR catalytic silencer also comprises a gas mixing device, and the gas mixing device comprises: a first baffle plate, which is installed between the air inlet pipe and the catalyst carrier layer, and a swirl hole is arranged on the periphery of the first baffle plate; a second baffle plate, which is arranged between the first baffle plate and the catalyst carrier layer, and air holes are evenly opened on the second baffle plate; a porous tube, which is arranged between the first baffle plate and the second baffle plate, and the two ends pass through the first baffle plate and the second baffle plate respectively, and the porous tube comprises a necking portion, a throat portion, and an expansion portion which are connected in sequence, and silencer holes are evenly opened on the throat portion; a first flow equalizing plate, which is arranged between the second baffle plate and the catalyst carrier layer.

[0009] In a preferred embodiment, the porous tube further comprises: a plurality of flow-turbulating holes formed on the expansion portion.

[0010] In a preferred embodiment, the SCR catalytic muffler further includes: a deamination layer disposed between the catalyst carrier layer and the exhaust pipe; and a second flow balancing plate disposed between the deamination layer and the catalyst carrier layer.

[0011] In a preferred embodiment, the SCR catalytic muffler includes: a muffler cotton layer, which is arranged on a side of the shell close to the outlet pipe, the outlet pipe extends toward the shell and passes through the muffler cotton layer, and a through hole is opened on the outlet pipe.

[0012] In a preferred embodiment, a nitrogen oxide sensor is installed on the sound-absorbing cotton layer.

[0013] In a preferred embodiment, both sides of the shell are arranged in a trapezoidal structure, and the diameter of any one of the trapezoidal structures close to the catalyst support layer is larger than the diameter of the side away from the catalyst support layer.

[0014] In a preferred embodiment, a carrier replacement port is also provided on the shell, and the carrier replacement port is used to replace the catalyst carrier.

[0015] 1. The airflow through the swirl holes on the first baffle of the SCR catalytic muffler of the present application collides with the airflow from the muffler hole, generating strong disturbances, increasing the turbulence intensity, facilitating the breakup and decomposition of urea aqueous solution droplets, accelerating the mixing of urea and exhaust gas, and avoiding the formation of urea crystals.

[0016] 2. The SCR catalytic muffler of the present application can eliminate most of the noise through the necking part, throat, expansion part of the porous tube, the trapezoidal structure of the shell, and the muffler cotton layer, thereby playing the role of muffler and noise reduction.

[0017] 3. The SCR catalytic muffler of the present application oxidizes the mixed gas after the catalyst carrier layer is treated and then oxidized by the deamination layer, and then oxidized by the oxidant, so as to effectively control the escaped ammonia and prevent it from escaping into the atmosphere and causing secondary pollution to the atmosphere. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Other characteristics, features and advantages of the present invention will become clear by reading the following description of the exemplary embodiments with reference to the accompanying drawings. The accompanying drawings, which are incorporated into the specification and constitute a part of the specification, illustrate embodiments of the present invention and are used together with the description to explain the principles of the present invention. In these drawings, similar reference numerals are used to represent similar elements. The drawings described below are some embodiments of the present invention, not all embodiments. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 Structural diagram of the utility model SCR catalytic muffler;

[0020] Figure 2 A cross-sectional view of the SCR catalytic muffler of the utility model;

[0021] Figure 3 Structural diagram of the gas mixing device of the utility model;

[0022] Figure 4 The front view of the SCR catalytic muffler of the utility model;

[0023] Figure 5 Side view of the SCR catalytic muffler of the utility model;

[0024] Figure 6 A top view of the SCR catalytic muffler of the utility model;

[0025] In the figure: 10, shell; 11, air inlet pipe; 12, air outlet pipe; 20, catalyst carrier layer; 30, gas mixing device; 31, first baffle; 311, swirl hole; 32, second baffle; 321, vent hole; 40, porous tube; 41, necking part; 42, throat; 43, expansion part; 421, silencer hole; 50, first equalizing plate; 431, spoiler hole; 21, deammonification layer; 51, second equalizing plate; 60, silencer cotton layer; 121, through hole; 61, nitrogen oxide sensor; 13, carrier replacement port. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical scheme and advantages of the embodiment of the utility model clearer, the technical scheme in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the utility model. It should be noted that the embodiments in this application and the features in the embodiments can be combined with each other arbitrarily without conflict.

[0027] The SCR catalytic muffler is described in detail below in conjunction with the accompanying drawings and embodiments. Example 1

[0028] An SCR catalytic silencer includes a shell 10, wherein both sides of the shell 10 are connected to an intake pipe 11 and an outlet pipe 12 respectively, and a catalyst carrier layer 20 is installed in the shell 10. The SCR catalytic silencer also includes a gas mixing device 30, and the gas mixing device 30 includes: a first partition plate 31, which is installed between the intake pipe 11 and the catalyst carrier layer 20, and a swirl hole 311 is arranged on the periphery of the first partition plate 31; a second partition plate 32, which is arranged between the first partition plate 31 and the catalyst carrier layer 20, and air holes 321 are evenly opened on the second partition plate 32; a porous tube 40, which is arranged between the first partition plate 31 and the second partition plate 32, and the two ends pass through the first partition plate 31 and the second partition plate 32 respectively, and the porous tube 40 includes a necking portion 41, a throat portion 42, and an expansion portion 43 which are connected in sequence, and silencer holes 421 are evenly opened on the throat portion 42; a first flow equalizing plate 50, which is arranged between the second partition plate 32 and the catalyst carrier layer 20.

[0029] During operation, the exhaust gas of the diesel engine is input through the intake pipe 11, and the urea solution is sprayed in from the injection port on one side of the intake pipe 11. When passing through the gas mixing device 30, a part of the mixed gas enters the porous tube 40, and then flows out from the silencer hole 421 and the expansion part 43 respectively, and the other part of the mixed gas enters the cavity between the first baffle 31 and the second baffle 32 from the swirl hole 311 on the first baffle 31, generating a rotating airflow, and collides with the airflow from the silencer hole 421, generating a strong disturbance, increasing the turbulence intensity, which is beneficial to the breakup and decomposition of urea aqueous solution droplets, accelerating the mixing of urea and exhaust gas, and avoiding the formation of urea crystals. The mixed gas finally flows out from the vent hole 321, mixes with the mixed gas flowing out of the expansion part 43, and reacts with the catalyst carrier layer 20 after rectification by the first flow equalizing plate 50, and is finally discharged from the outlet pipe 12.

[0030] The mixed gas contracts and expands through the necking portion 41, the throat portion 42, and the expansion portion 43, so that the cross section of the low airflow suddenly increases, and the gas pressure and flow rate are instantly reduced, which plays a role in silencing.

[0031] Among them, the setting of the first flow equalizing plate 50 can improve the uniformity of the mixed airflow distribution at the front end of the catalyst, effectively prevent the urea crystallization in the catalyst block and the solid particles in the diesel engine exhaust from depositing, thereby achieving the purpose of improving the conversion efficiency.

[0032] The apertures of the throat 42 , the silencer hole 421 and the swirl hole 311 need to ensure that the mixed gas can intersect and merge in the cavity between the first partition plate 31 and the second partition plate 32 .

[0033] Wherein, a catalyst reaction block is arranged on the catalyst carrier layer 20 . Example 2

[0034] Example 2 is an improvement on Example 1. In order to further improve the uniformity of mixing of the exhaust gas and the urea solution, the porous tube 40 may further include: a plurality of spoiler holes 431 , and the plurality of spoiler holes 431 are evenly arranged on the expansion portion 43 .

[0035] When working, the airflow in the cavity between the first partition plate 31 and the second partition plate 32 can merge with the airflow flowing out of the throat 42 and the expansion part 43 through the turbulence hole 431, thereby generating strong turbulence, thereby improving the uniformity of the mixed airflow distribution at the front end of the catalyst, preventing urea crystallization in the catalyst block and solid particles in the diesel engine exhaust from depositing, thereby achieving the purpose of improving the conversion efficiency.

[0036] The spoiler holes 431 may also be configured as through holes that can generate rotating airflow, so that the airflow passing through the spoiler holes 431 generates a rotating flow effect, thereby increasing the turbulence intensity and improving the uniformity of the distribution of the urea solution and the diesel exhaust gas. Example 3

[0037] Example 3 is an improvement on Example 1. In order to prevent ammonia from escaping from the SCR catalytic muffler, the SCR catalytic muffler may further include: a deammoniation layer 21 disposed between the catalyst carrier layer 20 and the exhaust pipe 12; and a second flow equalizing plate 51 disposed between the deammoniation layer 21 and the catalyst carrier layer 20.

[0038] Among them, the deamination layer 21 can be a stainless steel wire mesh and an oxidant block loaded on the surface of the stainless steel wire mesh. When the exhaust gas is treated by the catalyst carrier layer 20, nitrogen and water are generated. The remaining ammonia passes through the deamination layer 21 and is oxidized by the oxidant. Moreover, the generated product is adsorbed on the wire mesh, thereby effectively controlling the escaping ammonia and preventing it from escaping into the atmosphere and causing secondary pollution to the atmosphere. Example 4

[0039] Embodiment 4 is an improvement on Embodiment 1. To further improve the silencing effect of the device, the SCR catalytic muffler may further include: a muffler cotton layer 60, which is arranged on the side of the housing 10 close to the outlet pipe 12. The outlet pipe 12 extends toward the housing 10 and passes through the muffler cotton layer 60. A through hole 121 is provided on the outlet pipe 12. A nitrogen oxide sensor 61 is installed on the muffler cotton layer 60.

[0040] When working, the airflow passes through the sound-absorbing cotton layer 60, which can obviously produce the effect of noise reduction and silencing. At the same time, the through hole 121 on the air outlet pipe 12 also plays the role of noise reduction and silencing.

[0041] The exhaust pipe 12 is located at one end of the shell 10 and has a trumpet opening structure, which can collect exhaust gas and reduce exhaust back pressure. Example 5

[0042] Example 5 is an improvement on Example 1. To further improve the noise reduction capability, specifically, both sides of the shell 10 are arranged in a trapezoidal structure, and the diameter of any trapezoidal structure close to the catalyst carrier layer 20 is larger than the diameter away from the catalyst carrier layer 20.

[0043] The two sides of the shell 10 are arranged in a trapezoidal structure, and the airflow can eliminate most of the low-frequency noise through sudden expansion and contraction. Example 6

[0044] Embodiment 6 is an improvement on Embodiment 1, and a carrier replacement port 13 is further provided on the housing 10, and the carrier replacement port 13 is used to replace the catalyst carrier.

[0045] The carrier replacement port 13 is provided to facilitate the staff to replace the catalyst carrier.

[0046] The carrier replacement port 13 may be configured as a drawer, with the drawer being sealed around the sides.

[0047] The working principle of the SCR catalytic muffler in this application.

[0048] During operation, the exhaust gas of the diesel engine is input through the intake pipe 11, and the urea solution is sprayed in from the injection port on one side of the intake pipe 11. When passing through the gas mixing device 30, a part of the mixed gas enters the porous tube 40, and then flows out from the silencer hole 421 and the expansion part 43 respectively, and the other part of the mixed gas enters the cavity between the first baffle 31 and the second baffle 32 from the swirl hole 311 on the first baffle 31, generating a rotating airflow, and collides with the airflow from the silencer hole 421, generating a strong disturbance, increasing the turbulence intensity, which is beneficial to the breakup and decomposition of urea aqueous solution droplets, accelerating the mixing of urea and exhaust gas, and avoiding the formation of urea crystals. The mixed gas flows out from the vent hole 321, mixes with the mixed gas flowing out of the expansion part 43, and is rectified by the first flow equalizing plate 50 and treated by the catalyst carrier layer 20 to generate nitrogen and water. The remaining ammonia passes through the deammonification layer 21, is oxidized by the oxidant to prevent ammonia from escaping, and finally passes through the silencer cotton layer 60 and is discharged from the outlet pipe 12.

[0049] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprises" or any other variants thereof are intended to cover non-exclusive inclusion, so that an article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such article or device. In the absence of further restrictions, the elements defined by the sentence "includes..." do not exclude the existence of other identical elements in the article or device including the elements.

[0050] The above embodiments are only used to illustrate the technical solution of the utility model but not to limit it. The utility model is described in detail with reference to the preferred embodiments. It should be understood by those skilled in the art that the technical solution of the utility model can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the utility model, and all should be included in the scope of the claims of the utility model.

Claims

1. An SCR catalytic muffler, comprising a housing (10), wherein two sides of the housing (10) are respectively connected to an air inlet pipe (11) and an air outlet pipe (12), and a catalyst carrier layer (20) is installed in the housing (10), characterized in that: The SCR catalytic muffler further comprises a gas mixing device (30), The gas mixing device (30) comprises: A first partition plate (31) is installed between the intake pipe (11) and the catalyst carrier layer (20), and a swirl hole (311) is provided on the peripheral side of the first partition plate (31); The second separator (32) is arranged between the first separator (31) and the catalyst carrier layer (20), and the second separator (32) is evenly provided with ventilation holes (321). A porous tube (40) is arranged between the first partition plate (31) and the second partition plate (32), with two ends passing through the first partition plate (31) and the second partition plate (32) respectively, the porous tube (40) comprising a necking portion (41), a throat portion (42), and an expansion portion (43) connected in sequence, and sound-absorbing holes (421) are evenly opened on the throat portion (42); The first flow balancing plate (50) is arranged between the second separator (32) and the catalyst carrier layer (20).

2. The SCR catalytic muffler according to claim 1, characterized in that: The porous tube (40) further comprises: A plurality of spoiler holes (431) are provided on the expansion portion (43).

3. The SCR catalytic muffler according to claim 1, characterized in that: The SCR catalytic muffler also includes: a deammoniation layer (21), arranged between the catalyst carrier layer (20) and the gas outlet pipe (12); The second flow balancing plate (51) is arranged between the deamination layer (21) and the catalyst support layer (20).

4. The SCR catalytic muffler according to claim 1, characterized in that: The SCR catalytic muffler comprises: The sound-absorbing cotton layer (60) is arranged on a side of the shell (10) close to the air outlet pipe (12); the air outlet pipe (12) extends toward the shell (10) and passes through the sound-absorbing cotton layer (60); and a through hole (121) is provided on the air outlet pipe (12).

5. The SCR catalytic muffler according to claim 4, characterized in that: A nitrogen and oxygen sensor (61) is installed on the sound-absorbing cotton layer (60).

6. The SCR catalytic muffler according to claim 1, characterized in that: Both sides of the shell (10) are arranged in a trapezoidal structure, and the diameter of a side of any of the trapezoidal structures close to the catalyst carrier layer (20) is greater than the diameter of a side away from the catalyst carrier layer (20).

7. The SCR catalytic muffler according to claim 1, characterized in that: The housing (10) is also provided with a carrier replacement port (13), and the carrier replacement port (13) is used to replace the catalyst carrier.

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