Exhaust emission system for dual-fuel engine

Abstract

The invention discloses an exhaust gas emission system for a dual-fuel engine in the technical field of engine exhaust gas treatment. The exhaust gas emission system comprises a cooling unit, a catalytic conversion unit, a catalytic reduction unit, an oxidation catalysis unit and a particle trapping unit which are communicated in sequence, the cooling unit comprises a shell, a heat exchange medium inlet pipe, a heat exchange medium outlet pipe, an air inlet pipe, an air outlet pipe, a heat exchange pipe and a spraying assembly, wherein the heat exchange medium inlet pipe, the heat exchange medium outlet pipe, the air inlet pipe and the air outlet pipe are arranged on the shell, and the heat exchange pipe is arranged in the shell and communicates with the air inlet pipe and the air outlet pipe. The heat exchange pipe comprises a second pipe body and a first pipe body rotationally arranged at the end of the second pipe body, and the first pipe body is connected with a driving device. The driving device drives the first pipe body of the heat exchange pipe to rotate when the spraying assembly sprays the heat exchange medium, so that the first pipe body is in uniform contact with the heat exchange medium; the temperature of the waste gas is fully reduced, and the situation that the performance and the service life of follow-up waste gas treatment equipment are affected due to the fact that the temperature of the waste gas is too high is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of engine exhaust gas treatment, in particular to an exhaust gas emission system for a dual-fuel engine. Background Art

[0002] As a power device that can use both traditional fuel (such as diesel) and clean gas fuel (such as natural gas or liquefied petroleum gas), dual-fuel engines have gradually become a popular choice in the fields of industry, transportation, etc.; in the operation of dual-fuel engines, exhaust gas emissions are a key link. In order to reduce the emission of harmful gases (such as nitrogen oxides, hydrocarbons, etc.) and particulate matter in the exhaust gas, the exhaust gas usually passes through a series of post-treatment equipment, such as catalytic converters, selective catalytic reduction (SCR) systems, particulate filters (DPF), etc. However, the exhaust gas usually needs to be cooled before entering these treatment equipment to avoid high temperature from damaging the equipment or affecting the treatment effect; currently, the common exhaust gas cooling method is to exchange heat with the exhaust gas flowing inside the heat exchange pipe through a heat exchange medium (such as coolant or air), thereby achieving exhaust gas cooling;

[0003] Existing exhaust gas cooling technology has certain limitations. Normally, the heat exchange medium is sprayed onto the outer surface of the heat exchange pipe through a spraying facility. However, since the heat exchange pipe is fixed, the contact area between the heat exchange medium and the pipe is limited, resulting in low heat exchange efficiency. This may cause the exhaust gas temperature to fail to be fully reduced, thereby affecting the performance and life of subsequent exhaust gas treatment equipment. Summary of the invention

[0004] The object of the present invention is to provide an exhaust gas emission system for a dual-fuel engine to solve the problem in the background art that the heat exchange pipe is fixed and the contact area between the heat exchange medium and the pipe is limited, resulting in low heat exchange efficiency.

[0005] To achieve the above object, the present invention provides the following technical solution: an exhaust gas emission system for a dual-fuel engine, comprising: a cooling unit, a catalytic conversion unit, a catalytic reduction unit, an oxidation catalytic unit and a particle capture unit connected in sequence;

[0006] The cooling unit comprises a shell, a heat exchange medium inlet pipe, a heat exchange medium outlet pipe, an air inlet pipe and an air outlet pipe arranged on the shell, a heat exchange pipe arranged in the shell and connected to the air inlet pipe and the air outlet pipe respectively, and a spray assembly located above the heat exchange pipe and connected to the heat exchange medium inlet pipe;

[0007] The heat exchange tube includes a second tube body and a first tube body rotatably arranged on the end of the second tube body, and the first tube body is connected to a driving device, which is used to drive the first tube body to rotate when the spray assembly sprays the heat exchange medium.

[0008] Preferably, a support rod is provided in the second tube body, the support rod extends into the first tube body and extends along the length direction of the first tube body, and a scraper for fitting with the inner wall of the first tube body is provided on the side wall of the support rod.

[0009] Preferably, two partitions are provided in the shell, and the two partitions are used to divide the inner cavity of the shell into two second cavities and a first cavity between the two second cavities;

[0010] There are two second tubes, which are respectively arranged on two partitions.

[0011] Preferably, a collecting trough is provided between the two partitions, and the collecting trough is located between the spray assembly and the first tube body. A liquid inlet channel for communicating with the collecting trough is provided on one partition, and a liquid discharge channel is provided on the other partition. A guide hole is provided in the support rod, and a liquid inlet pipe for connecting the guide hole with the liquid inlet channel is provided on the support rod, and a liquid outlet pipe for connecting the guide hole with the liquid discharge channel is provided on the support rod.

[0012] Preferably, the inner cavity bottom of the collecting tank is inclined toward the liquid inlet channel, and the guide hole is inclined toward the liquid discharge channel;

[0013] Wherein, the liquid inlet channel is located above the second tube body, and the liquid discharge channel is located below the second tube body.

[0014] Preferably, a spiral conveying roller is rotatably provided in the liquid discharge channel.

[0015] Preferably, a turning assembly is rotatably provided in the air inlet pipe, and a transmission assembly is provided on the turning assembly so that the spiral conveying roller rotates synchronously with the turning assembly.

[0016] Preferably, the outer shell comprises a shell and a shell cover detachably connected to the shell, and the partition is detachably arranged in the shell.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. The first tube body of the heat exchange tube is driven by a driving device to rotate when the spray assembly sprays the heat exchange medium, so that the first tube body is in uniform contact with the heat exchange medium to ensure that the exhaust gas inside the heat exchange tube is fully heat exchanged, so that the exhaust gas temperature is fully reduced, and the exhaust gas temperature is avoided to be too high to affect the performance and life of the subsequent exhaust gas treatment equipment. When the first tube body rotates, the scraper rotates relative to the first tube body to scrape off the soot or impurities attached to the inner wall of the first tube body to avoid affecting the heat exchange between the heat exchange medium and the exhaust gas, so as to ensure that the exhaust gas is fully heat exchanged, so as to reduce the temperature of the exhaust gas to a preset value;

[0019] 2. The heat exchange medium sprayed by the spray assembly is collected through the collection tank, and the heat exchange medium is introduced into the guide hole of the support rod for circulation, so as to exchange heat with the exhaust gas inside the first pipe body, thereby further ensuring sufficient cooling of the exhaust gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the exhaust gas emission system of the present invention;

[0021] Figure 2 It is a schematic diagram of the cooling unit structure of the present invention;

[0022] Figure 3 It is a schematic diagram of the cross-sectional structure of the housing of the present invention;

[0023] Figure 4 This is a schematic diagram of the connection structure between the partition and the heat exchange tube of the present invention;

[0024] Figure 5 This is a schematic diagram of the cross-sectional structure of the heat exchange tube of the present invention;

[0025] Figure 6 For the present invention Figure 3 A schematic diagram of the enlarged structure in the middle.

[0026] In the figure: 1. cooling unit; 101. outer shell; 1011. shell; 1012. shell cover; 102. heat exchange medium inlet pipe; 103. heat exchange medium outlet pipe; 104. exhaust pipe; 105. air inlet pipe; 106. spray assembly; 107. heat exchange pipe; 1071. first tube body; 1072. second tube body; 108. partition; 109. flip assembly; 110. transmission assembly; 111. first cavity; 112. second cavity; 113. collecting tank; 114. liquid inlet channel; 115. scraper; 116. support rod; 117. liquid inlet pipe; 118. liquid outlet pipe; 119. liquid discharge channel; 120. spiral conveyor roller; 2. catalytic conversion unit; 3. catalytic reduction unit; 4. oxidation catalytic unit; 5. particle capture unit. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] Example 1

[0029] See also Figure 1, an exhaust gas emission system for a dual-fuel engine, comprising: a cooling unit 1, a catalytic conversion unit 2, a catalytic reduction unit 3, an oxidation catalytic unit 4 and a particulate trap unit 5 in sequence; the exhaust gas of the dual-fuel engine is discharged after being processed by the above-mentioned equipment in sequence, wherein the catalytic conversion unit 2 refers to a three-way catalytic converter, which is used to reduce carbon monoxide, hydrocarbons and nitrogen oxides in the exhaust gas, the catalytic reduction unit 3 refers to a selective catalytic reduction (SCR) device, which uses a urea solution to convert nitrogen oxides in the exhaust gas into nitrogen and water, the oxidation catalytic unit 4 refers to an oxidation catalyst, which converts carbon monoxide and hydrocarbons in the exhaust gas into carbon dioxide and water through an oxidation reaction, and the particulate trap unit 5 refers to a particulate trap, which is used to capture and store particulate matter in the exhaust gas; the above-mentioned equipment is a prior art for treating the exhaust gas of a dual-fuel engine, and will not be described in detail here.

[0030] See also Figure 2 , Figure 3 and Figure 4 The cooling unit 1 includes a shell 101, a heat exchange medium inlet pipe 102 is connected to the top wall of the shell 101, a heat exchange medium outlet pipe 103 is connected to the bottom wall of the shell 101, and an air inlet pipe 105 and an air outlet pipe 104 are connected to the two side walls of the shell 101 respectively; two partitions 108 are symmetrically arranged in the inner cavity of the shell 101, and the two partitions 108 are used to divide the inner cavity of the shell 101 into two second cavities 112 and a heat exchange medium outlet pipe 103 between the two second cavities 112. The first cavity 111 and the two second cavities 112 are respectively connected to the air inlet pipe 105 and the exhaust pipe 104. A heat exchange pipe 107 (a plurality of heat exchange pipes 107 are arranged horizontally) is arranged between the two partitions 108, and the two second cavities 112 are connected through the heat exchange pipe 107. A spray assembly 106 (the spray assembly 106 includes a pipeline and a nozzle arranged on the pipeline) is installed on the top of the inner cavity of the first cavity 111, and the spray assembly 106 is connected to the heat exchange medium inlet pipe 102.

[0031] Among them, see Figure 3 and Figure 4 The heat exchange tube 107 includes two second tube bodies 1072 and a first tube body 1071 rotatably installed between the two second tube bodies 1072 (the first tube body 1071 rotates around the axis of the second tube body 1072), and a driving device (such as a motor) is installed on the outer shell 101, and the driving device is used to drive the first tube body 1071 to rotate.

[0032] The specific process of exhaust gas being treated by the cooling unit 1 is that the exhaust gas enters the inner cavity of the second cavity 112 on the left side through the intake pipe 105, and then enters the interior of the heat exchange tube 107. At the same time, the heat exchange medium (such as heat transfer oil) passes through the heat exchange medium inlet pipe 102 and is sprayed onto the outer wall of the heat exchange tube 107 by the spray assembly 106, and exchanges heat with the exhaust gas in the heat exchange tube 107 to reduce the exhaust gas temperature; after the exhaust gas temperature is reduced, it is discharged from the shell 101 through the heat exchange tube 107 and the exhaust pipe 104 to the catalytic conversion unit 2 for the next step of treatment; in the process of heat exchange between the exhaust gas and the heat exchange medium, the driving device drives the first tube body 1071 to rotate, so that the first tube body 1071 is in uniform contact with the heat exchange medium, so that the exhaust gas is fully heat exchanged; the heat exchange medium after heat exchange is discharged from the heat exchange medium outlet pipe 103; heat exchange between the heat exchange medium and the exhaust gas is not only used to cool the exhaust gas, but also to recover heat.

[0033] In this embodiment, as a further optimized solution, please refer to Figure 4 and Figure 5 A support rod 116 is fixedly provided inside the second tube body 1072, and the support rod 116 extends into the first tube body 1071 and extends along the length direction of the first tube body 1071. A scraper 115 is provided on the side wall of the support rod 116, and a side wall of the scraper 115 away from the support rod 116 is in contact with the inner wall of the first tube body 1071; during the rotation of the first tube body 1071, since the second tube body 1072 is stationary, the support rod 116 will not rotate either, so that the scraper 115 rotates relative to the first tube body 1071, so as to scrape off the soot or impurities attached to the inner wall of the first tube body 1071, so as to avoid affecting the heat exchange between the heat exchange medium and the exhaust gas, thereby ensuring sufficient heat exchange of the exhaust gas and reducing the exhaust gas temperature.

[0034] In this embodiment, as a further optimized solution, please refer to Figure 2 , Figure 3 and Figure 6 The outer shell 101 includes a shell 1011 and a shell cover 1012, the shell cover 1012 is detachably connected to the shell 1011 (such as by bolts), and the partition 108 is detachably arranged in the inner cavity of the shell 1011 (such as by snap-fitting or bolting); the shell cover 1012 is removed from the shell 1011, and the partition 108 is removed from the inside of the shell 1011, so that the heat exchange tube 107 can be removed for cleaning.

[0035] Example 2

[0036] As a further optimized solution of Example 1, please refer to Figure 3 , Figure 4 , Figure 5 and Figure 6A collecting tank 113 is provided between the two partitions 108, and the collecting tank 113 is located between the spray assembly 106 and the first tube body 1071. The collecting tank 113 and the first tube body 1071 are staggered so that the collecting tank 113 is not directly above the first tube body 1071, ensuring that the spray assembly 6 can directly spray the heat exchange medium on the outer surface of the first tube body 1071; a liquid inlet channel 114 is provided inside one partition 108, and the liquid inlet channel 114 is located at one end of the collecting tank 113 and is connected to the collecting tank 113, and a liquid discharge channel 119 is provided inside the other partition 108, and a guide hole is provided inside the support rod 116 (the guide hole extends along the length direction of the support rod 116), and a liquid inlet pipe 117 for connecting the guide hole with the liquid inlet channel 114 is provided on the support rod 116, and a liquid discharge channel 119 is provided on the support rod 116. 19 connected to the liquid outlet pipe 118; the bottom of the inner cavity of the collecting tank 113 is inclined toward the liquid inlet channel 114, and the guide hole is inclined toward the liquid discharge channel 119; the liquid inlet channel 114 is located above the second tube body 1072, and the liquid discharge channel 119 is located below the second tube body 1072; the collecting tank 113 is used to collect the heat exchange medium sprayed by the spray assembly 106 (that is, the collecting tank 113 collects the heat exchange medium falling around the heat exchange tube 107), and the heat exchange medium inside the collecting tank 113 passes through the liquid inlet channel 114 and the liquid inlet pipe 117 to enter the inside of the guide hole for heat exchange with the exhaust gas inside the first tube body 1071 to ensure sufficient cooling of the exhaust gas. The heat exchange medium after heat exchange enters the inside of the liquid discharge channel 119 through the liquid outlet pipe 118, and then is discharged into the inner cavity of the first cavity 111, and finally discharged from the shell 101 through the heat exchange medium outlet pipe 103.

[0037] It should be noted that the support rod 116 is made of a heat-conducting metal material, such as steel.

[0038] In this embodiment, as a further optimized solution, please refer to Figure 6 A spiral conveying roller 120 is provided for rotation in the inner cavity of the discharge channel 119; the spiral conveying roller 120 rotates to assist in the discharge of the heat exchange medium inside the discharge channel 119, thereby preventing the heat exchange medium from being unable to circulate inside the liquid inlet channel 114, the guide hole and the discharge channel 119, and ensuring the heat exchange effect of the heat exchange medium on the exhaust gas from the inside of the heat exchange tube 107.

[0039] In this embodiment, as a further optimized solution, please refer to Figure 3 and Figure 6A flip assembly 109 is provided for internal rotation of the air intake pipe 105 (the flip assembly 109 includes a rotating rod and blades provided on the side wall of the rotating rod, the rotating rod is rotatably installed in the inner cavity of the air intake pipe 105, and the rotating rod is perpendicular to the flow direction of the exhaust gas), and a transmission assembly 110 is provided on the outer shell 101. The transmission assembly 110 includes a rotating shaft, which is connected to the spiral conveying roller 120 through a gear set, and the rotating shaft is driven by a belt to the rotating rod; when the exhaust gas flows inside the air intake pipe 105, it will drive the flip assembly 109 to rotate, and through the transmission assembly 110, the spiral conveying roller 120 rotates synchronously with the flip assembly 109, and the power of the exhaust gas flow is used to drive the spiral conveying roller 120 to rotate, thereby saving energy.

[0040] It should be noted that a thorn structure is installed on the rotating rod of the flipping assembly 109, so that the flipping assembly 109 can only rotate in one direction, ensuring that the rotation direction of the spiral conveying roller 120 is fixed (rotating in one direction), so that the rotation of the spiral conveying roller 120 will only discharge the heat exchange medium inside the drainage channel 119.

[0041] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An exhaust gas emission system for a dual-fuel engine, characterized in that: include: A cooling unit (1), a catalytic conversion unit (2), a catalytic reduction unit (3), an oxidation catalytic unit (4) and a particle capture unit (5) connected in sequence; The cooling unit (1) comprises a shell (101), a heat exchange medium inlet pipe (102) arranged on the shell (101), a heat exchange medium outlet pipe (103), an air inlet pipe (105) and an exhaust pipe (104), a heat exchange pipe (107) arranged in the shell (101) and connected to the air inlet pipe (105) and the exhaust pipe (104), respectively, and a spray assembly (106) located above the heat exchange pipe (107) and connected to the heat exchange medium inlet pipe (102); The heat exchange tube (107) comprises a second tube body (1072) and a first tube body (1071) rotatably arranged at the end of the second tube body (1072), and the first tube body (1071) is connected to a driving device, and the driving device is used to drive the first tube body (1071) to rotate when the spray assembly (106) sprays the heat exchange medium.

2. An exhaust gas emission system for a dual-fuel engine according to claim 1, characterized in that: A support rod (116) is provided in the second tube body (1072), and the support rod (116) extends into the first tube body (1071) and extends along the length direction of the first tube body (1071). A scraper (115) is provided on the side wall of the support rod (116) for fitting with the inner wall of the first tube body (1071).

3. An exhaust gas emission system for a dual fuel engine according to claim 2, characterized in that: Two partitions (108) are provided in the shell (101), and the two partitions (108) are used to divide the inner cavity of the shell (101) into two second cavities (112) and a first cavity (111) located between the two second cavities (112); There are two second tubes (1072) and they are respectively arranged on two partitions (108).

4. An exhaust gas emission system for a dual fuel engine according to claim 3, characterized in that: A collecting trough (113) is provided between the two partitions (108), and the collecting trough (113) is located between the spray assembly (106) and the first tube body (1071). A liquid inlet channel (114) for communicating with the collecting trough (113) is provided on one of the partitions (108), and a liquid discharge channel (119) is provided on the other partition (108). A flow guide hole is provided in the support rod (116), and a liquid inlet pipe (117) for communicating the flow guide hole with the liquid inlet channel (114) is provided on the support rod (116). A liquid outlet pipe (118) for communicating the flow guide hole with the liquid discharge channel (119) is provided on the support rod (116).

5. An exhaust gas emission system for a dual fuel engine according to claim 4, characterized in that: The inner cavity bottom of the collecting tank (113) is inclined toward the liquid inlet channel (114), and the guide hole is inclined toward the liquid discharge channel (119); Wherein, the liquid inlet channel (114) is located above the second tube body (1072), and the liquid discharge channel (119) is located below the second tube body (1072).

6. An exhaust gas emission system for a dual fuel engine according to claim 4, characterized in that: A spiral conveying roller (120) is rotatably arranged in the liquid discharge channel (119).

7. An exhaust gas emission system for a dual fuel engine according to claim 6, characterized in that: A turning assembly (109) is rotatably arranged in the air inlet pipe (105), and a transmission assembly (110) is arranged on the turning assembly (109) so that the spiral conveying roller (120) rotates synchronously with the turning assembly (109).

8. An exhaust gas emission system for a dual-fuel engine according to claim 3, characterized in that: The housing (101) comprises a shell (1011) and a shell cover (1012) detachably connected to the shell (1011), and the partition (108) is detachably arranged in the shell (1011).

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