Methanol Dual-Fuel Engine Bypass DOC System

Abstract

This utility model belongs to the field of marine engine exhaust gas treatment technology, specifically relating to a bypass-type DOC system for methanol dual-fuel engines. It includes a catalytic converter, a branch pipe at one end of the catalytic converter, and a manifold at the other end. A bypass emission channel is provided between the branch pipe and the manifold, and a control valve is installed on the bypass emission channel. An exhaust gas main is installed at the end of the branch pipe furthest from the catalytic converter, and a controller is installed on the exhaust gas main. A concentration sensor is installed inside the branch pipe, and the concentration sensor and control valve are electrically connected to the controller. A catalyst carrier is installed inside the catalytic converter. This device can treat exhaust gas pollutants differently for methanol-diesel dual-fuel and pure diesel modes, and is more suitable for the limited installation space in the ship's engine room.

Description

Technical Field

[0001] This utility model belongs to the field of marine engine exhaust gas treatment technology, specifically relating to a methanol dual-fuel engine bypass DOC system. Background Technology

[0002] With increasingly stringent restrictions on ship exhaust emissions from maritime organizations, methanol dual-fuel engines are widely used as a clean power solution to replace traditional diesel engines. Methanol dual-fuel engines can flexibly switch between methanol-diesel dual-fuel combustion modes and pure diesel combustion modes. In methanol-diesel dual-fuel mode, due to the incomplete combustion of methanol, the exhaust gas contains a large amount of unburned hydrocarbons; in pure diesel mode, the exhaust gas is mainly composed of nitrogen oxides and particulate matter. A DOC (diesel oxidation catalyst) is an exhaust purification device installed in the engine exhaust system, whose main function is to reduce harmful substances in diesel engine emissions through catalytic oxidation reactions. However, existing DOC systems mostly adopt a fixed-path design; regardless of the engine's fuel mode, the exhaust gas must flow through the catalyst. This results in a large amount of nitric oxide being oxidized to nitrogen dioxide in pure diesel mode, leading to environmental pollution and health risks. At the same time, traditional catalysts have low removal rates for methanol-derived hydrocarbons, failing to meet the requirements for high-efficiency purification. Furthermore, when frequently switching between the two fuel modes, the catalyst is prone to activity decay due to temperature fluctuations and composition changes, increasing unnecessary catalyst loss.

[0003] Chinese patent CN221299294U discloses a marine fuel engine exhaust gas treatment device and a ship. The device includes: a fuel engine configured to emit exhaust gas, which includes nitrogen oxides (NOx); a mixer connected to the fuel engine and receiving the exhaust gas; the mixer having a reducing component with a concentration greater than that of NOx; and a reactor connected to the mixer, where the reducing component and NOx react to convert the NOx. This patent removes NOx from the exhaust gas by providing a reducing component and reacting it with NOx, while improving the conversion efficiency and stability of NOx. However, this patent lacks adaptability to methanol-diesel dual-fuel systems, cannot specifically treat differentiated pollutants, and has a complex system structure, large size and weight, poor compatibility with the limited space of a ship's engine room, requires continuous replenishment of the reducing agent during operation, and has a higher maintenance frequency, resulting in higher operating and maintenance costs. Utility Model Content

[0004] The purpose of this invention is to provide a methanol dual-fuel engine bypass DOC system that can treat exhaust pollutants differently for methanol-diesel dual-fuel mode and pure diesel mode, while reducing the size and weight of the equipment and making it more suitable for the limited installation space in the ship's engine room.

[0005] To achieve the above objectives, the technical solution of this utility model is as follows:

[0006] A methanol dual-fuel engine bypass DOC system includes a catalytic converter, a splitter pipe at one end of the catalytic converter, a manifold at the other end of the catalytic converter, a bypass discharge channel between the splitter pipe and the manifold, a control valve on the bypass discharge channel, a tail gas main pipe at the end of the splitter pipe away from the catalytic converter, a controller on the tail gas main pipe, a concentration sensor inside the splitter pipe, and both the concentration sensor and the control valve are electrically connected to the controller. A catalyst carrier is installed inside the catalytic converter.

[0007] Furthermore, the catalyst support is cordierite honeycomb, and the surface of the cordierite honeycomb is coated with a platinum catalyst coating or a palladium catalyst coating.

[0008] Furthermore, the catalytic treatment device is equipped with a fixing frame and a clamping frame inside in conjunction with the catalyst carrier, and both the fixing frame and the clamping frame are cylindrical in shape.

[0009] Furthermore, the clamping frame, together with the catalyst carrier, is located inside the fixed frame, and the diameter of the fixed frame is larger than the diameter of the clamping frame.

[0010] Furthermore, a dust interception net is installed inside the diversion pipe.

[0011] Furthermore, the catalytic treatment device is equipped with pressure sensor one and pressure sensor two, and the catalyst support is placed between pressure sensor one and pressure sensor two.

[0012] Furthermore, a heating plate is provided between the fixing frame and the clamping frame, and the heating plate, pressure sensor one, and pressure sensor two are all electrically connected to the controller.

[0013] Furthermore, the inner wall of the bypass emission channel is provided with a heat-insulating coating.

[0014] Furthermore, a sealing ring is installed between the control valve and the bypass discharge channel, and the sealing ring is made of graphite-based composite material.

[0015] Furthermore, both the branch pipe and the manifold are made of stainless steel.

[0016] The beneficial effects of this utility model are as follows:

[0017] By monitoring the exhaust gas composition of the methanol dual-fuel engine in real time through a concentration sensor, the controller receives the real-time data from the concentration sensor and automatically adjusts the control valve according to the changes in the concentration of hydrocarbons and nitrogen oxides in the exhaust gas, thereby achieving differentiated treatment for methanol-diesel dual-fuel mode and pure diesel mode. In methanol-diesel dual-fuel mode, when the concentration sensor detects a high concentration of hydrocarbons in the exhaust gas, the controller controls the control valve to close the bypass emission channel, and the exhaust gas passes through the catalytic treatment device to remove unburned hydrocarbons. In pure diesel mode, when the concentration sensor detects a high concentration of nitrogen oxides in the exhaust gas, the controller controls the control valve to open the bypass emission channel, reducing the direct contact between the exhaust gas and the catalyst carrier, and reducing the amount of nitrogen dioxide generated. The combination of the diversion pipe, manifold pipe and bypass emission channel results in a more compact structure, reducing the size and weight of the equipment, adapting to the space of the ship, and lowering the operating cost. Attached Figure Description

[0018] Figure 1 This is a partial structural schematic diagram of the present invention;

[0019] Figure 2 This is a partial structural cross-sectional view of the diversion pipe, concentration sensor, and dust interception net in this utility model;

[0020] Figure 3 This is a schematic diagram of the catalyst support structure in this utility model;

[0021] Figure 4 This is a schematic diagram of the catalyst carrier, fixing frame, clamping frame and heating plate in this utility model;

[0022] Figure 5 This is a partial structural cross-sectional view of the catalytic treatment device, pressure sensor 1, pressure sensor 2, catalyst carrier, and clamping frame in this utility model.

[0023] Figure 6 This is a schematic diagram of the catalyst carrier, clamping frame, and heating plate in this utility model;

[0024] Figure 7 This is a schematic diagram of the heating plate in this utility model;

[0025] In the picture:

[0026] 1. Catalytic treatment unit; 2. Diverter pipe; 3. Manifold pipe; 4. Bypass emission channel; 5. Control valve; 6. Exhaust gas main pipe; 7. Concentration sensor; 8. Controller; 9. Catalyst carrier; 10. Fixing frame; 11. Clamping frame; 12. Heating plate; 13. Dust interception net; 14. Pressure sensor one; 15. Pressure sensor two. Detailed Implementation

[0027] The present invention will now be described and illustrated in detail with reference to the embodiments.

[0028] Example 1

[0029] like Figure 1-7 As shown, the methanol dual-fuel engine bypass DOC system of this utility model includes a catalytic treatment device 1. A diversion pipe 2 is provided at one end of the catalytic treatment device 1, and a manifold pipe 3 is provided at the other end of the catalytic treatment device 1. A bypass discharge channel 4 is provided between the diversion pipe 2 and the manifold pipe 3. A control valve 5 is provided on the bypass discharge channel 4. A tail gas main pipe 6 is provided at the end of the diversion pipe 2 away from the catalytic treatment device 1. A controller 8 is provided on the tail gas main pipe 6. A concentration sensor 7 is provided inside the diversion pipe 2. The concentration sensor 7 and the control valve 5 are both electrically connected to the controller 8. A catalyst carrier 9 is provided inside the catalytic treatment device 1.

[0030] A complete bypass purification system was constructed by setting up a catalytic treatment device 1, a diversion pipe 2, a manifold pipe 3, a bypass emission channel 4, a control valve 5, a concentration sensor 7, a controller 8, and a catalyst carrier 9. The concentration sensor 7 monitors the exhaust gas composition in real time and transmits the data to the controller 8. The controller 8 can automatically adjust the control valve 5 to achieve differentiated treatment in methanol-diesel dual-fuel mode and pure diesel mode. It can remove hydrocarbons in methanol-diesel dual-fuel mode and reduce nitrogen dioxide generation in diesel mode. At the same time, the diversion pipe 2, manifold pipe 3, and bypass emission channel 4 have a compact overall structure, which is suitable for the limited space of ships.

[0031] The catalyst support 9 is a cordierite honeycomb, with a platinum or palladium catalyst coating applied to its surface. The cordierite honeycomb has a large specific surface area, providing ample space for the catalytic reaction. The platinum or palladium catalyst coating exhibits excellent catalytic activity for the oxidation of hydrocarbons, significantly improving the removal efficiency of hydrocarbons in the exhaust gas under methanol-diesel dual-fuel mode and enhancing the system's purification capacity.

[0032] The catalyst treatment device 1 is equipped with a fixing frame 10 and a clamping frame 11 inside the catalyst carrier 9. Both the fixing frame 10 and the clamping frame 11 are cylindrical.

[0033] The clamping frame 11 is installed inside the fixing frame 10 in conjunction with the catalyst carrier 9, and the diameter of the fixing frame 10 is larger than the diameter of the clamping frame 11. The fixing frame 10 and the clamping frame 11 can stably fix the catalyst carrier 9, prevent it from shifting or being damaged, ensure that the catalyst carrier 9 is always in the optimal working position, and improve the reliability of system operation.

[0034] The diversion pipe 2 is equipped with a dust interception net 13. The dust interception net 13 can effectively filter particulate matter and dust in the exhaust gas, prevent these impurities from entering the catalytic treatment device 1 and coming into contact with the catalyst carrier 9, prevent the catalyst carrier 9 from being blocked or contaminated, extend the service life of the catalyst carrier 9, and reduce the maintenance frequency and cost of the system.

[0035] The catalytic treatment device 1 is equipped with pressure sensor 14 and pressure sensor 2 15, and the catalyst carrier 9 is disposed between pressure sensor 14 and pressure sensor 2 15.

[0036] A heating plate 12 is disposed between the fixing frame 10 and the clamping frame 11. The heating plate 12, pressure sensor 14, and pressure sensor 15 are all electrically connected to the controller 8. Pressure sensor 14 and pressure sensor 15 are respectively located on both sides of the catalyst carrier 9, and can monitor the pressure difference before and after the catalyst carrier 9 in real time. By observing changes in the pressure difference, it is possible to determine whether the catalyst carrier 9 is blocked, thus ensuring the normal operation of the system. The controller 8 can control the operation of the heating plate 12, adjust the temperature of the catalyst carrier 9, and improve the catalytic efficiency.

[0037] The inner wall of the bypass discharge channel 4 is equipped with a heat insulation coating.

[0038] A sealing ring is provided between the control valve 5 and the bypass discharge channel 4. The sealing ring is made of graphite-based composite material.

[0039] Both the diversion fitting 2 and the manifold fitting 3 are made of stainless steel. Stainless steel has excellent corrosion resistance and high temperature resistance, and can withstand the high temperature and corrosive environment of the exhaust gas, extending the service life of the diversion fitting 2 and the manifold fitting 3, and ensuring the long-term stable operation of the system.

[0040] Working principle and process:

[0041] When the methanol dual-fuel engine is in methanol-diesel dual-fuel mode, the exhaust gas enters the splitter pipe 2 through the exhaust gas main pipe 6. The concentration sensor 7 inside the splitter pipe 2 monitors the exhaust gas composition in real time. If a high concentration of hydrocarbons is detected, the sensor transmits the data to the controller 8 on the exhaust gas main pipe 6. After receiving the data, the controller 8 closes the regulating valve 5 on the bypass emission channel 4. At this time, the exhaust gas cannot pass through the bypass emission channel 4 and can only enter the catalytic treatment unit 1. Inside the catalytic treatment unit 1, the exhaust gas comes into contact with the internal catalyst carrier 9. The catalyst carrier 9 is a cordierite honeycomb, and its surface platinum or palladium catalyst coating can oxidize the hydrocarbons in the exhaust gas, achieving the purification purpose. At the same time, the fixing frame 10 and the clamping frame 11 inside the catalytic treatment unit 1 firmly fix the catalyst carrier 9. The heating plate 12 between the fixing frame 10 and the clamping frame 11 heats according to the instructions of the controller 8 to ensure that the catalyst carrier 9 is in the optimal catalytic reaction state. The purified exhaust gas is discharged through the manifold 3.

[0042] When the methanol dual-fuel engine switches to pure diesel mode, the exhaust gas first enters the splitter pipe 2. The concentration sensor 7 detects a high concentration of nitrogen oxides in the exhaust gas and transmits the data to the controller 8. The controller 8 then controls the control valve 5 to open, allowing most of the exhaust gas to be discharged directly through the bypass emission channel 4. Due to the back pressure generated by the catalyst carrier 9 in the catalytic converter 1, only a small amount of exhaust gas enters the catalytic converter 1, greatly reducing the contact between the exhaust gas and the catalyst carrier 9, thereby reducing the amount of nitrogen dioxide generated. Finally, the exhaust gas from the bypass emission channel 4 and the small amount treated by the catalytic converter 1 are combined and discharged through the manifold 3.

Claims

1. A methanol dual fuel engine by-pass DOC system comprising a catalytic treatment device (1), characterized in that, A catalytic treatment device (1) is provided with a diversion pipe (2) at one end and a manifold pipe (3) at the other end. A bypass discharge channel (4) is provided between the diversion pipe (2) and the manifold pipe (3). A control valve (5) is provided on the bypass discharge channel (4). A tail gas main pipe (6) is provided at the end of the diversion pipe (2) away from the catalytic treatment device (1). A controller (8) is provided on the tail gas main pipe (6). A concentration sensor (7) is provided inside the diversion pipe (2). The concentration sensor (7) and the control valve (5) are electrically connected to the controller (8). A catalyst carrier (9) is provided inside the catalytic treatment device (1).

2. The methanol dual-fuel engine bypass DOC system according to claim 1, characterized in that, The catalyst support (9) is a cordierite honeycomb, and the surface of the cordierite honeycomb is coated with a platinum catalyst coating or a palladium catalyst coating.

3. The methanol dual-fuel engine bypass DOC system according to claim 1, characterized in that, The catalyst processing device (1) is equipped with a fixed frame (10) and a clamping frame (11) inside the catalyst carrier (9). Both the fixed frame (10) and the clamping frame (11) are cylindrical.

4. The methanol dual-fuel engine bypass DOC system according to claim 3, characterized in that, The clamping frame (11) is arranged inside the fixed frame (10) in conjunction with the catalyst carrier (9), and the diameter of the fixed frame (10) is larger than the diameter of the clamping frame (11).

5. The methanol dual-fuel engine bypass DOC system according to claim 1, characterized in that, The diversion pipe fitting (2) is equipped with a dust interception net (13).

6. The methanol dual-fuel engine bypass DOC system according to claim 3, characterized in that, The catalytic treatment device (1) is equipped with pressure sensor one (14) and pressure sensor two (15), and the catalyst carrier (9) is located between pressure sensor one (14) and pressure sensor two (15).

7. The methanol dual-fuel engine bypass DOC system according to claim 6, characterized in that, A heating plate (12) is provided between the fixing frame (10) and the clamping frame (11). The heating plate (12), pressure sensor one (14) and pressure sensor two (15) are all electrically connected to the controller (8).

8. The methanol dual-fuel engine bypass DOC system according to claim 1, characterized in that, The inner wall of the bypass discharge channel (4) is provided with a heat insulation coating.

9. The methanol dual-fuel engine bypass DOC system according to claim 1, characterized in that, A sealing ring is provided between the control valve (5) and the bypass discharge channel (4), and the sealing ring is made of graphite-based composite material.

10. The methanol dual-fuel engine bypass DOC system according to claim 1, characterized in that, The materials of the branch fitting (2) and the manifold fitting (3) are both stainless steel.

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