An SCR hybrid system

Abstract

This invention provides an SCR mixing system, belonging to the field of exhaust gas treatment technology. The SCR mixing system includes: an intake chamber, located on the top side of the housing, connected to both an air inlet and a urea inlet, and a spiral intake pipe connected to the urea inlet within the intake chamber; and a mixing chamber, located beside the intake chamber and connected to it via the spiral intake pipe, and an installation pipe within the mixing chamber. The installation pipe is not concentric with the central axis of the housing, and spiral blades are fixedly mounted on the installation pipe. This SCR mixing system effectively breaks down and decomposes urea aqueous solution, accelerating the mixing of urea solution and exhaust gas, preventing urea crystallization. Furthermore, because the installation pipe is not concentric with the central axis of the housing, the cross-sectional area of ​​the mixed airflow continuously increases and decreases during the transport process by the spiral blades, repeatedly circulating and causing continuous changes in airflow pressure and velocity, thus continuously reducing noise during the movement of the mixed airflow.

Description

Technical Field

[0001] The invention relates to the technical field of tail gas treatment, and in particular to an SCR mixing system. 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 October 2008, IMO officially adopted the amendment to Annex VI of MARPOL73 / 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. CN111894710A 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 high tail 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 hybrid system. Summary of the invention

[0007] In view of the above problems, the present invention provides an SCR hybrid system.

[0008] An SCR mixing system includes a shell, and an air inlet and an air outlet are respectively opened on both sides of the shell, and a urea inlet is opened on the top side of the shell close to the air inlet. The SCR mixing system includes: an air inlet chamber, which is arranged on the top side of the shell and is connected with the air inlet and the urea inlet respectively, and a spiral air inlet pipe is arranged in the air inlet chamber, and the spiral air inlet pipe is connected with the urea inlet; a mixing chamber, which is arranged beside the air inlet chamber and is connected with the air inlet chamber through the spiral air inlet pipe, and a mounting pipe is arranged in the mixing chamber, the mounting pipe is not concentric with the central axis of the shell, and a spiral blade is fixedly arranged on the mounting pipe.

[0009] In a preferred embodiment, the mounting tube is located at a height of 1 / 5-2 / 5 of the housing.

[0010] In a preferred embodiment, the spiral blades include: a first spiral section, which is arranged on the bottom side of the air inlet chamber, and the spiral blades on both sides of the mounting tube are arranged at the same height, and the cross-section of the mixing chamber on the bottom side of the air inlet chamber is cylindrical; a second spiral section, which is arranged on one side of the first spiral section, and the spiral blades on both sides of the mounting tube are arranged at different heights.

[0011] In a preferred embodiment, the first helical segment and the second helical segment have different handedness.

[0012] In a preferred embodiment, the SCR mixing system further comprises: a spoiler pipe passing through the spiral blades, wherein the diameter of the spoiler pipe on both sides between two adjacent spiral blades is larger than the diameter in the middle, and an air outlet is arranged in the middle of the spoiler pipe.

[0013] In a preferred embodiment, the SCR mixing system further comprises: a trumpet-shaped joint fixedly connected to the air inlet end of the spoiler pipe.

[0014] In a preferred embodiment, the SCR mixing system further includes: an equalizing plate disposed in the spoiler tube.

[0015] In a preferred embodiment, the SCR hybrid system further comprises: a baffle plate, which is arranged in the housing and on a side of the mounting pipe close to the air outlet, and a through hole is arranged on the baffle plate.

[0016] 1. The entire mixing process of the SCR mixing system of the present application can effectively crush and decompose the urea aqueous solution, accelerate the mixing of the urea solution and the exhaust gas, and avoid the formation of urea crystals. At the same time, the installation pipe is not concentric with the central axis of the shell. During the transportation of the mixed airflow by the spiral blades, the cross-sectional area of ​​the airflow is continuously increased and reduced, and the cycle is repeated, so that the pressure and flow rate of the airflow are constantly changing, and the noise reduction effect is continuously played during the movement of the mixed airflow.

[0017] 2. The SCR mixing system of the present application is provided with a first spiral section and a second spiral section. During the transportation of the mixed airflow in the first spiral section, the cross-sectional area of ​​the airflow does not change, and only the collision of the mixed airflow occurs, so that the urea and the exhaust gas are mixed to avoid the formation of urea crystals. During the transportation of the first spiral section, mixing and silencing effects occur. The setting of the two spiral sections can more fully mix the urea and the exhaust gas to avoid the formation of urea crystals.

[0018] 3. The SCR mixing system of the present application is provided with a spoiler tube. When the mixed airflow enters the spoiler tube and flows out through the air outlet, it collides with the mixed airflow on the spiral blade side, thereby increasing the turbulence intensity, accelerating the mixing of urea and exhaust gas, and avoiding the formation of urea crystals. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Other characteristics, features and advantages of the present invention will become clear by reading the following description of 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 from these drawings without paying creative work.

[0020] Figure 1 The appearance structure diagram of the SCR hybrid system of the present invention;

[0021] Figure 2 A side view of the SCR hybrid system of the present invention;

[0022] Figure 3 Internal structure diagram of the SCR hybrid system of the present invention;

[0023] Figure 4 The structural diagram of the spiral blade of the present invention;

[0024] Figure 5 Internal structure diagram of SCR hybrid system embodiment 3 of the present invention;

[0025] Figure 6 Sectional view of the SCR hybrid system of the present invention at position AA;

[0026] Figure 7 Cross-sectional view of the SCR hybrid system of the present invention at position BB.

[0027] In the figure: 10, shell; 11, air inlet; 12, air outlet; 13, urea inlet; 20, air inlet chamber; 21, spiral air inlet pipe; 30, mixing chamber; 31, mounting pipe; 40, spiral blade; 41, first spiral section; 42, second spiral section; 50, spoiler pipe; 51, air outlet; 52, trumpet-shaped joint; 53, equalizing plate; 32, baffle; 33, through hole. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. 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.

[0029] The SCR hybrid system is described in detail below with reference to the accompanying drawings and embodiments.

[0030] Example 1

[0031] An SCR mixing system includes a shell 10, and an air inlet 11 and an air outlet 12 are respectively opened on both sides of the shell 10, and a urea inlet 13 is opened on the top side of the shell 10 close to the air inlet 11. The SCR mixing system includes: an air inlet chamber 20, which is arranged on the top side of the shell 10 and is connected with the air inlet 11 and the urea inlet 13 respectively, and a spiral air inlet pipe 21 is arranged in the air inlet chamber 20, and the spiral air inlet pipe 21 is connected with the urea inlet 13; a mixing chamber 30, which is arranged beside the air inlet chamber 20 and is connected with the air inlet chamber 20 through the spiral air inlet pipe 21, and a mounting pipe 31 is arranged in the mixing chamber 30, the mounting pipe 31 is not concentric with the central axis of the shell 10, and a spiral blade 40 is fixedly arranged on the mounting pipe 31.

[0032] During operation, urea solution is sprayed into the urea inlet 13, and the exhaust gas enters the housing 10 from the air inlet 11. The urea solution and the exhaust gas are mixed in the spiral air inlet pipe 21 to generate a rotating airflow for preliminary mixing. The mixed gas enters the mixing chamber 30, and then further collides and mixes under the action of the spiral blades 40, and is finally discharged from the air outlet 12. The entire mixing process can effectively crush and decompose the urea aqueous solution, accelerate the mixing of the urea solution and the exhaust gas, and avoid the formation of urea crystals. At the same time, the installation pipe 31 is not concentric with the central axis of the housing 10. During the transportation process of the mixed airflow under the action of the spiral blades 40, the cross-sectional area of ​​the airflow is continuously increased and reduced, and the cycle is repeated, so that the pressure and flow rate of the airflow are continuously changed, and the noise reduction effect is continuously played during the movement of the mixed airflow.

[0033] Specifically, the device utilizes the sudden change of the pipe cross section to cause the change of impedance during the sound propagation process to produce reflection and interference of sound energy, thereby reducing the sound energy radiated outward from the muffler to achieve the purpose of noise reduction.

[0034] The mounting tube 31 is located at a height of 1 / 5-2 / 5 of the housing 10 .

[0035] Example 2

[0036] Embodiment 2 is an improvement on Embodiment 1, and the improvement includes: the spiral blades 40 may include: a first spiral segment 41, which is arranged on the bottom side of the air inlet chamber 20, and the spiral blades 40 on both sides of the mounting tube 31 are arranged at the same height, and the cross-section of the mixing chamber 30 on the bottom side of the air inlet chamber 20 is cylindrical; a second spiral segment 42, which is arranged on one side of the first spiral segment 41, and the spiral blades 40 on both sides of the mounting tube 31 are not arranged at the same height.

[0037] The spiral blade 40 includes a first spiral section 41 and a second spiral section 42. During the transportation of the mixed airflow in the first spiral section 41, the cross-sectional area of ​​the airflow does not change, only the collision of the mixed airflow occurs, so that the urea and the exhaust gas are mixed to avoid the formation of urea crystals. During the transportation of the second spiral section 42, mixing and silencing effects occur. The setting of the two spiral sections can more fully mix the urea and the exhaust gas to avoid the formation of urea crystals.

[0038] Example 3

[0039] Embodiment 3 is an improvement on Embodiment 1, and the improvement includes: the rotation directions of the first helical segment 41 and the second helical segment 42 may be different.

[0040] Among them, two spiral sections with different rotation directions are provided, so that the mixed gas collides between the first spiral section 41 and the second spiral section, thereby generating strong disturbance, increasing the turbulence intensity, being 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.

[0041] Example 4

[0042] Embodiment 4 is an improvement on Embodiment 1, and the improvement includes: the SCR mixing system may further include: a spoiler pipe 50 passing through the spiral blades 40, the diameters on both sides of the spoiler pipe 50 between two adjacent spiral blades 40 are larger than the diameter in the middle, and an air outlet 51 is provided in the middle of the spoiler pipe 50.

[0043] Among them, by setting the spoiler tube 50, when the mixed airflow enters the spoiler tube 50 and flows out through the air outlet 51, it collides with the mixed airflow on the side of the spiral blade 40, which can increase the turbulence intensity, accelerate the mixing of urea and exhaust gas, and avoid the formation of urea crystals.

[0044] The diameters of the two sides of the spoiler tube 50 are larger than the diameter of the middle part, so that the spoiler tube 50 generates suction, similar to the effect of a venturi, which facilitates the mixed airflow to be sucked into the spoiler tube 50 .

[0045] Example 5

[0046] Embodiment 5 is an improvement on Embodiment 1, and the improvement includes: the SCR mixing system further includes: a trumpet-shaped joint 52 fixedly connected to the air inlet end of the spoiler pipe 50 .

[0047] The trumpet-shaped joint 52 at the air inlet end of the spoiler tube 50 is designed to increase the air inlet area of ​​the air inlet end of the spoiler tube 50 , which is more conducive to the mixed airflow entering the spoiler tube 50 .

[0048] Example 6

[0049] Example 6 is an improvement on Example 1, and the improvement includes: the SCR mixing system further includes: an equalizing plate 53 disposed in the spoiler tube 50 .

[0050] Among them, an equalizing plate 53 with an "X-shaped" cross-section is arranged in the spoiler tube 50, and a matching air outlet hole 51 is opened at a corresponding position on the spoiler tube 50. The mixed airflow enters from the air inlet end of the spoiler tube 50, is then separated by the equalizing plate 53, and then flows out from the air outlet hole 51, so that the airflow flowing out of the spoiler tube 50 is uniform, which can more fully produce a spoiler effect on the mixed airflow on the side of the spiral blade 40, increase the turbulence intensity, accelerate the mixing of urea and exhaust gas, and avoid the formation of urea crystals.

[0051] Example 7

[0052] Embodiment 7 is an improvement on Embodiment 1, and the improvement includes: the SCR hybrid system further includes: a baffle 32 disposed in the housing 10 and disposed on a side of the mounting pipe 31 close to the air outlet 12 , and a through hole 33 is disposed on the baffle 32 .

[0053] When the mixed gas flows through the spiral section, the baffle 32 is provided to improve the uniformity of the mixed gas at the gas outlet.

[0054] 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.

[0055] The above embodiments are only used to illustrate the technical solution of the present invention and are not intended to limit the present invention. The present invention 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 present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention, and should be included in the scope of the claims of the present invention.

Claims

1. An SCR mixing system, comprising a housing (10), wherein an air inlet (11) and an air outlet (12) are respectively provided on both sides of the housing (10), and a urea inlet (13) is provided on the top side of the housing (10) near the air inlet (11), wherein: The SCR hybrid system comprises: An air intake chamber (20) is arranged on the top side of the housing (10) and is communicated with the air intake port (11) and the urea inlet (13) respectively, and a spiral air intake pipe (21) is arranged in the air intake chamber (20), and the spiral air intake pipe (21) is communicated with the urea inlet (13); a mixing chamber (30) arranged beside the air inlet chamber (20) and connected to the air inlet chamber (20) via the spiral air inlet pipe (21); a mounting pipe (31) is arranged in the mixing chamber (30); the mounting pipe (31) is not concentric with the central axis of the housing (10); and a spiral blade (40) is fixedly arranged on the mounting pipe (31); The SCR mixing system further comprises: a spoiler pipe (50) passing through the spiral blades (40), the diameter of the spoiler pipe (50) on both sides between two adjacent spiral blades (40) being larger than the diameter in the middle, and an air outlet hole (51) is provided in the middle of the spoiler pipe (50).

2. The SCR hybrid system according to claim 1, characterized in that: The mounting pipe (31) is located at a height position of 1 / 5-2 / 5 of the housing (10).

3. The SCR hybrid system according to claim 1, characterized in that: The spiral blade (40) comprises: A first spiral section (41) is arranged at the bottom side of the air inlet chamber (20), the spiral blades (40) on both sides of the mounting tube (31) are arranged at the same height, and the cross section of the mixing chamber (30) at the bottom side of the air inlet chamber (20) is arranged in a cylindrical shape; The second spiral section (42) is arranged on one side of the first spiral section (41), and the spiral blades (40) on both sides of the mounting tube (31) are arranged at different heights.

4. The SCR hybrid system according to claim 3, characterized in that: The first helical segment (41) and the second helical segment (42) have different hand directions.

5. The SCR hybrid system according to claim 1, characterized in that: The SCR hybrid system further comprises: The trumpet-shaped joint (52) is fixedly connected to the air inlet end of the spoiler pipe (50).

6. The SCR hybrid system according to claim 1 or 5, characterized in that: The SCR hybrid system further comprises: The equalizing plate (53) is arranged in the spoiler tube (50).

7. The SCR hybrid system according to claim 1, characterized in that: The SCR hybrid system further comprises: A baffle (32) is arranged in the housing (10) and on a side of the mounting tube (31) close to the air outlet (12), and a through hole (33) is arranged on the baffle (32).

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