Energy-saving type tail gas treatment device for oil tanker

Abstract

This utility model provides an energy-saving exhaust gas treatment device for oil tankers, including a mixing mechanism, a urea injection mechanism, and a catalytic reaction tank. A bevel gear assembly consisting of gear one and gears two and three meshing on its upper and lower sides is used. Gears two and three have an outer shaft and an inner shaft fixedly connected inside, respectively, achieving coaxial reversal. Spiral blades and impellers are fixedly connected to the outer walls of the inner and outer shafts, respectively, to reverse and cut and mix the flowing gas, improving the degree of urea droplet breakage. This achieves a two-stage mixing process between the exhaust gas and urea droplets, increasing the mixing efficiency between them, reducing the risk of urea crystallization due to insufficient mixing, and improving the efficiency of urea droplets decomposing into ammonia under the high temperature of the exhaust gas. It also achieves a relatively efficient conversion of nitrogen oxides in the exhaust gas into nitrogen under the action of a catalyst.

Description

Technical Field

[0001] This utility application relates to the field of tanker exhaust gas treatment technology, and in particular to an energy-saving exhaust gas treatment device for tankers. Background Technology

[0002] SCR is a technology that uses urea solution and catalyst to convert nitrogen oxides in exhaust gas into nitrogen and water. It is widely used in tankers, automobiles and power plants. On ships, urea injection pumps are used to directly inject urea, which is then decomposed by the waste heat of the high-temperature flue gas generated by the diesel engine to produce ammonia, thereby carrying out the conversion reaction of nitrogen oxides.

[0003] Chinese patent CN218688137U discloses an SCR reactor, which uses multiple catalyst layer units arranged sequentially inside the reactor to catalyze the gas passing through in sequence. At present, SCR technology still has the following problems: insufficient mixing of urea solution and tail gas, resulting in uneven mixing of ammonia and nitrogen oxides generated by decomposition, leading to local excess ammonia and untreated nitrogen oxides being discharged, forming secondary pollution.

[0004] Therefore, there is an urgent need to provide an energy-saving exhaust gas treatment device for oil tankers that can fully mix urea solution and exhaust gas to efficiently convert nitrogen oxides. Utility Model Content

[0005] The purpose of this application is to achieve thorough mixing of urea solution and engine exhaust gas, and to provide an energy-saving exhaust gas treatment device for oil tankers compared with the prior art. The device includes a catalytic reaction tank, a mixing chamber and a gas mixing mechanism. The mixing chamber has a mixing cavity inside, and a mixing pipe is fixedly connected inside the mixing cavity. A connecting pipe and an air inlet pipe are fixedly connected to the upper and lower ends of the mixing pipe, respectively. The gas mixing mechanism is located inside the mixing pipe.

[0006] The gas mixing mechanism includes a motor, a base, a coupling, a drive shaft, a fixed seat, an outer shaft, an impeller, an inner shaft, and helical blades. The fixed seat contains gears one, two, and three. The base is fixedly connected to the outer wall of the mixing tube, penetrating the interior of the mixing chamber and extending to its outer side. The motor is fixedly connected to the end face of the base, and its output end is fixedly connected to the drive shaft via the coupling. The end of the drive shaft furthest from the coupling movably passes through the fixed seat and is fixedly connected to gear one. Gears two and three are meshed on the upper and lower sides of gear one, respectively. The upper end of the outer shaft is fixedly connected to gear three. The impeller is fixedly connected to the outer wall of the outer shaft. The upper end of the inner shaft movably passes through the inner side of the outer shaft and is fixedly connected to gear two. The helical blades are fixedly connected to the outer wall of the inner shaft and are located below the impeller.

[0007] Furthermore, the outer end of the fixing seat is fixedly connected to the inner wall of the mixing pipe by multiple support rods.

[0008] Furthermore, a support seat is rotatably connected to the lower end of the inner shaft, and the support seat is fixedly connected to the inner wall of the mixing tube.

[0009] Furthermore, a flow equalization orifice plate is fixedly connected to the inner wall of the mixing pipe, and the flow equalization orifice plate is located above the fixed base.

[0010] Furthermore, the outer shaft is a hollow structure, and a wear-resistant bushing is fixedly connected to its inner wall, while the inner shaft is rotatably connected inside the wear-resistant bushing.

[0011] Furthermore, it includes a urea tank and a urea pump located outside the mixing chamber. The urea tank and the urea pump are fixedly connected by a pipe. A nozzle is fixedly connected to the end of the urea pump away from the urea tank. The end of the nozzle away from the urea pump passes through the outer wall of the air intake pipe and extends into the inside of the air intake pipe. Multiple nozzles are fixedly connected to the side wall of the nozzle, and the nozzles face the inner cavity of the air intake pipe.

[0012] Furthermore, two deflectors are fixedly connected at the bend of the intake pipe.

[0013] Compared to existing technologies, the advantages of this application are:

[0014] (1) The coaxial reversing structure composed of three bevel gear sets can form a high-strength shear layer. Compared with the traditional static mixing structure, it accelerates gas flow and improves gas mixing efficiency. The combination between the spiral blades and the impeller makes the urea droplets break up more thoroughly, reducing the risk of incomplete decomposition of urea droplets colliding with the inner wall of the pipe and forming crystals.

[0015] (2) A flow equalization plate is designed at the outlet of the mixing mechanism to improve the uniformity of airflow, break the large-scale vortex generated in the reversing structure, reduce the risk of excessively high or low local ammonia concentration, and also reduce the possibility of high-speed airflow directly scouring the catalyst, thus extending the catalyst's lifespan. Attached Figure Description

[0016] Figure 1 This is a front view of a partial section of the pipeline in this application;

[0017] Figure 2 This is a cross-sectional view of the hybrid structure of this application;

[0018] Figure 3 This is an exploded view of the hybrid structure of this application;

[0019] Figure 4 This is a perspective view of the hybrid structure of this application;

[0020] Figure 5 This is a perspective view of the flow equalization orifice plate of this application;

[0021] Figure 6 This is a partial cross-sectional view of the urea injection device of this application;

[0022] Figure 7 This is a partial cross-sectional view of the air deflector in this application;

[0023] Figure 8 This is an external perspective view of this application.

[0024] Explanation of the labels in the diagram:

[0025] 1. Mixing tank, 2. Connecting pipe, 3. Catalytic reaction tank, 4. Urea tank, 5. Urea pump, 6. Nozzle, 7. Inlet pipe, 8. Nozzle, 9. Flow equalization plate, 10. Mixing pipe, 11. Motor, 12. Base, 13. Coupling, 14. Outlet pipe, 15. Drive shaft, 16. Guide plate, 17. Gear 1, 18. Fixing seat, 19. Gear 2, 20. Support seat, 21. Outer shaft, 22. Impeller, 23. Wear-resistant bushing, 24. Gear 3, 25. Inner shaft, 26. Spiral blade. Detailed Implementation

[0026] The embodiments will be described clearly and completely with reference to the accompanying drawings. All other embodiments obtained by those skilled in the art based on the embodiments in this application without creative effort are within the scope of protection of this application.

[0027] Example 1:

[0028] This utility model provides an energy-saving exhaust gas treatment device for oil tankers. Please refer to [link / reference]. Figure 1 The reactor includes a catalytic reaction vessel 3 and a mixing chamber 1. The mixing chamber 1 has a mixing cavity inside, and a mixing pipe 10 is fixedly connected inside the mixing cavity. The upper and lower ends of the mixing pipe 10 are respectively fixedly connected to a connecting pipe 2 and an inlet pipe 7. The catalytic reaction vessel 3 adopts the publicly available technology. Its principle is to use multiple catalyst layer units, which are arranged in sequence in the reactor to catalyze the gas passing through in sequence.

[0029] Please see 6 and Figure 8 It includes a urea tank 4 and a urea pump 5 located outside the mixing chamber 1. The urea tank 4 and the urea pump 5 are fixedly connected by a pipe. The end of the urea pump 5 away from the urea tank 4 is fixedly connected to a nozzle 8. One end of the nozzle 8 penetrates the outer wall of the air intake pipe 7 and extends into the interior of the air intake pipe 7. Multiple nozzles 6 are fixedly connected to the side wall of the nozzle 8. The nozzles 6 face the inner cavity of the air intake pipe 7.

[0030] Please see Figure 7 Two guide plates 16 are fixedly connected at the bend of the intake pipe 7. The guide plates 16 have a single arc structure. When the exhaust gas and urea droplets are initially mixed, they guide the flow of the mixed gas, reduce the impact of the gas on the bend of the intake pipe 7, and extend the service life of the intake pipe 7.

[0031] Working principle: When the exhaust gas from the tanker flows into the intake pipe 7, the urea pump 5 is turned on to draw urea solution from the urea tank 4 and spray atomized urea droplets into the intake pipe through the nozzle 8 and nozzle 6. The urea droplets and exhaust gas mix and flow into the mixing pipe 10. After mixing inside the mixing pipe 10, the mixture flows into the catalytic reaction tank 3 through the connecting pipe 2. Under the action of the catalyst layer unit, the nitrogen oxides in the exhaust gas are converted into nitrogen and water. The treated gas flows out from the bottom outlet pipe 14.

[0032] Example 2:

[0033] Based on the first embodiment, this embodiment adds a gas mixing mechanism inside the mixing tube 10, as detailed below:

[0034] Please see Figure 1-4 The gas mixing mechanism includes a motor 11, a base 12, a coupling 13, a drive shaft 15, a fixed seat 18, an outer shaft 21, an impeller 22, an inner shaft 25, and a spiral blade 26. The fixed seat 18 contains gears 17, 19, and 24, all of which are bevel gears. The base 12 is fixedly connected to the outer wall of the mixing pipe 10, and extends through the interior of the mixing chamber 1 to the outside of the mixing chamber 1. The motor 11 is fixedly connected to the end face of the base 12, and its output end is fixedly connected to the drive shaft 15 via the coupling 13. The other end of the drive shaft 15, away from the coupling 13, movably passes through the fixed end. The seat 18 is fixedly connected inside the gear 17. The gear 29 and gear 3 24 are meshed and connected to the upper and lower sides of the gear 17, respectively. The upper end of the outer shaft 21 is fixedly connected inside the gear 3 24. The impeller 22 is fixedly connected to the outer wall of the outer shaft 21. The upper end of the inner shaft 25 moves through the inner side of the outer shaft 21 and is fixedly connected inside the gear 29. The spiral blade 26 is fixedly connected to the outer wall of the inner shaft 25 and is located below the impeller 22. The spiral blade 26 and the impeller 22 rotate in opposite directions on the same axis, which improves the degree of breakage of urea droplets and thus improves the efficiency of urea solution decomposition and exhaust gas mixing.

[0035] Please see Figure 2 The outer end of the fixed base 18 is fixedly connected to the inner wall of the mixing pipe 10 by multiple support rods. The drive shaft 15 is rotatably connected to the inside of the fixed base 18 by a bearing 1. The outer shaft 21 passes through the fixed base 18 and extends into the inside of the fixed base 18, and the outer shaft 21 is rotatably connected to the inside of the fixed base 18 by a bearing 2. The inner shaft 25 passes through the fixed base 18 and extends into the inside of the fixed base 18, and the inner shaft 25 is rotatably connected to the inside of the fixed base 18 by a bearing 3.

[0036] Please see Figure 2 The lower end of the inner shaft 25 is rotatably connected to the inside of the support base 20 via a bearing, and the support base 20 is fixedly connected to the inner wall of the mixing tube 10.

[0037] Please see Figure 1 and Figure 5 A flow equalization plate 9 is fixedly connected to the inner wall of the mixing tube 10. The flow equalization plate 9 is located above the fixing seat 18. The setting of the flow equalization plate reduces the eddies generated by the gas after mixing, equalizes the flow velocity of the gas inside the connecting tube 2, reduces the occurrence of high-speed gas impacting the catalyst, and extends the service life of the catalyst.

[0038] Please refer to 2. The outer shaft 21 is a hollow structure, and a wear-resistant bushing 23 is fixedly connected to its inner wall. The inner shaft 25 is rotatably connected inside the wear-resistant bushing 23. The wear-resistant bushing 23 is used to improve the airtightness between the outer shaft 21 and the inner shaft 25. It is made of ceramic material, which has corrosion resistance and improves service life.

[0039] Compared with Example 1, this example adds the above-mentioned content. When urea droplets and exhaust gas enter the mixing pipe 10, the motor 11 is started. The motor 11 drives the drive shaft 15 to rotate counterclockwise through the coupling 13, thereby driving the gear 17 to rotate. The gears 19 and 24 meshing on the upper and lower sides of the gear 17 rotate clockwise and counterclockwise respectively, causing the inner shaft 25 and outer shaft 21 fixedly connected inside the gears 19 and 24 to rotate clockwise and counterclockwise respectively. When the gas and urea droplets flow upward from the bottom of the mixing pipe 10, the spiral blades 26 fixedly connected to the outer wall of the inner shaft 25 rotate clockwise to perform initial rotational mixing of the gas. The mixed gas flows upward clockwise, and the impeller 22 fixed to the outer wall of the outer shaft 21 rotates counterclockwise to perform secondary turbulent mixing of the mixed gas.

[0040] Through the above operations, this application uses a bevel gear set composed of gear 17, gear 29 and gear 324 to achieve the coaxial reversal process of impeller 22 and spiral blade 26, which performs two-stage mixing of exhaust gas and urea droplets, improves the gas mixing efficiency, and reduces the risk of urea crystallization caused by insufficient mixing of urea droplets and exhaust gas.

[0041] The above description is only the best implementation method adopted in this application in combination with current practical needs, but the scope of protection of this application is not limited thereto.

Claims

1. An energy-saving exhaust gas treatment device for oil tankers, comprising a catalytic reaction tank (3), a mixing chamber (1), and a gas mixing mechanism, characterized in that, The mixing chamber (1) has a mixing cavity inside, and a mixing pipe (10) is fixedly connected inside the mixing cavity. The upper and lower ends of the mixing pipe (10) are respectively fixedly connected to a connecting pipe (2) and an air inlet pipe (7). The gas mixing mechanism is set inside the mixing pipe (10). The gas mixing mechanism includes a motor (11), a base (12), a coupling (13), a drive shaft (15), a fixed seat (18), an outer shaft (21), an impeller (22), an inner shaft (25), and a spiral blade (26). The fixed seat (18) is equipped with gear one (17), gear two (19), and gear three (24). The base (12) is fixedly connected to the outer wall of the mixing pipe (10), and it penetrates the interior of the mixing chamber (1) and extends to the outside of the mixing chamber (1). The motor (11) is fixedly connected to the end face of the base (12), and its output end is fixedly connected to the drive shaft (15) through the coupling (13). The end of the drive shaft (15) away from the coupling (13) moves through the fixed seat (18) and is fixedly connected inside the gear one (17). The gear two (19) and gear three (24) are respectively meshed and connected to the upper and lower sides of the gear one (17). The upper end of the outer shaft (21) is fixedly connected inside the gear three (24). The impeller (22) is fixedly connected to the outer wall of the outer shaft (21). The upper end of the inner shaft (25) moves through the inner side of the outer shaft (21) and is fixedly connected inside the gear two (19). The spiral blade (26) is fixedly connected to the outer wall of the inner shaft (25) and is located below the impeller (22).

2. The energy-saving exhaust gas treatment device for oil tankers according to claim 1, characterized in that, The outer end of the fixed seat (18) is fixedly connected to the inner wall of the mixing pipe (10) by multiple support rods.

3. The energy-saving exhaust gas treatment device for oil tankers according to claim 2, characterized in that, The lower end of the inner shaft (25) is rotatably connected to a support seat (20), which is fixedly connected to the inner wall of the mixing tube (10).

4. The energy-saving exhaust gas treatment device for oil tankers according to claim 2, characterized in that, The inner wall of the mixing tube (10) is fixedly connected to a flow equalization plate (9), which is located above the fixing seat (18).

5. The energy-saving exhaust gas treatment device for oil tankers according to claim 3, characterized in that, The outer shaft (21) is a hollow structure, and a wear-resistant bushing (23) is fixedly connected to its inner wall. The inner shaft (25) is rotatably connected inside the wear-resistant bushing (23).

6. The energy-saving exhaust gas treatment device for oil tankers according to claim 1, characterized in that, It also includes a urea tank (4) and a urea pump (5) located outside the mixing tank (1). The urea tank (4) and the urea pump (5) are fixedly connected by a pipe. The end of the urea pump (5) away from the urea tank (4) is fixedly connected to a nozzle (8). The end of the nozzle (8) away from the urea pump (5) passes through the outer wall of the air pipe (7) and extends into the interior of the air inlet pipe (7). Multiple nozzles (6) are fixedly connected to the outer wall of the nozzle (8). The nozzles (6) face the inner cavity of the air inlet pipe (7).

7. The energy-saving exhaust gas treatment device for oil tankers according to claim 6, characterized in that, Two guide vanes (16) are fixedly connected at the bend of the air intake pipe (7).

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