Ship dual-fuel engine flue gas treatment system and treatment method

Abstract

The invention discloses a ship dual-fuel engine flue gas treatment system and method. The system comprises a high-frequency electron beam generator, a mixing reactor, a catalytic oxidation reactor, a gas-liquid conveying pipeline and a flue gas conveying pipeline which are sequentially connected in the gas emission direction, wherein the mixing reactor and the catalytic oxidation reactor are used for being matched with the high-frequency electron beam generator to generate free radicals; a first mixing section is formed between the high-frequency electron beam generator and the mixing reactor, and a second mixing section is formed between the mixing reactor and the catalytic oxidation reactor; the gas-liquid conveying pipeline is communicated with the first mixing section; the flue gas conveying pipeline is communicated with the second mixing section; wherein the catalytic oxidation reactor is internally provided with a metal catalytic oxidation reaction layer and a non-metal catalytic oxidation reaction layer which are sequentially arranged along the gas emission direction. According to the invention, a three-stage treatment mechanism of free radical pre-oxidation, self-heating catalytic oxidation and continuous catalytic oxidation is adopted, so that efficient removal of unburnt methane and ammonia gas in the engine flue gas is realized.

Description

Technical Field

[0001] The present invention relates to the field of ship exhaust gas treatment, and in particular to a ship dual-fuel engine exhaust gas treatment system and method. Background Art

[0002] As global awareness of environmental protection continues to increase, the impact of ship exhaust emissions on the atmospheric environment has received increasing attention. As a new type of power device, ship dual-fuel engines can use different types of fuels, such as natural gas and fuel oil, to improve energy efficiency and reduce operating costs. However, dual-fuel engines produce complex exhaust components during the combustion process, including a large amount of nitrogen oxides (NO x ), sulfur oxides (SO x ), particulate matter (PM), methane (CH4), ammonia (NH3) and other pollutants. These pollutants not only cause serious pollution to the atmospheric environment, causing environmental problems such as acid rain and haze, but also harm human health.

[0003] Catalytic oxidation technology is an effective method for exhaust gas treatment. Through the action of catalysts, it can accelerate the reaction between pollutants in the exhaust gas and oxygen, converting them into harmless substances. In the field of ship exhaust gas treatment, catalytic oxidation technology has also been applied to a certain extent. However, the existing catalytic oxidation technology still faces some problems when treating the exhaust gas of ship dual-fuel engines.

[0004] On the one hand, existing catalysts are insufficient in terms of activity and selectivity, making it difficult to efficiently treat multiple pollutants at the same time. For example, the catalytic oxidation efficiency of pollutants such as methane and ammonia is low, requiring higher reaction temperatures and longer reaction times, resulting in increased system energy consumption and low treatment efficiency. On the other hand, in the traditional catalytic oxidation reaction process, the activity of the catalyst is easily affected by impurities and moisture in the exhaust gas, resulting in catalyst deactivation, requiring frequent catalyst replacement, and increasing operating costs.

[0005] Therefore, a ship dual-fuel engine smoke treatment system and treatment method are needed to solve the above problems. Summary of the invention

[0006] The object of the present invention is to provide a ship dual-fuel engine flue gas treatment system and method, so as to achieve efficient removal of unburned methane and ammonia in the engine flue gas.

[0007] In order to solve the above technical problems, the present invention provides a ship dual-fuel engine flue gas treatment system, comprising a high-frequency electron beam generator connected in sequence along the gas discharge direction, a mixing reactor and a catalytic oxidation reactor for cooperating with the high-frequency electron beam generator to generate free radicals, a gas-liquid transmission pipeline, and a flue gas transmission pipeline; A first mixing section is formed between the high-frequency electron beam generator and the mixing reactor, and a second mixing section is formed between the mixing reactor and the catalytic oxidation reactor; The gas-liquid delivery pipeline is in communication with the first mixing section and is used to deliver the air and water vapor or fresh water required for the formation of the free radicals; The smoke conveying pipeline is in communication with the second mixing section; The catalytic oxidation reactor is built with a metal catalytic oxidation reaction layer and a non-metal catalytic oxidation reaction layer sequentially arranged along the gas discharge direction; The metal catalytic oxidation reaction layer is used for the initial catalytic oxidation of the free radicals and the flue gas, and under the irradiation of the electron beam, it can absorb electron energy to increase the temperature, thereby accelerating the catalytic oxidation of the free radicals and the flue gas; The non-metal catalytic oxidation reaction layer is used for continuous catalytic oxidation of the free radicals and the remaining flue gas, and can shield electron beam radiation.

[0008] Furthermore, the metal catalytic oxidation reaction layer is provided as a magnesium-aluminum alloy substrate loaded with CuO, A-MnO2, MoO3 and Fe3O4 as metal oxide catalysts; The non-metal catalytic oxidation reaction layer is configured as a ZSM-5 molecular sieve structure loaded with CuO and A-MnO2 as transition metal catalysts.

[0009] Furthermore, the input end of the catalytic oxidation reactor has a mixer body for mixing the free radicals with the flue gas.

[0010] Furthermore, the mixing reactor comprises a mixing chamber, a gas phase mixer and a metal foam catalytic filler; The gas phase mixer and the metal foam catalytic filler are arranged in the mixing chamber in sequence from the gas discharge direction; The gas phase mixer is used to form a uniform mixed gas flow; The metal foam catalytic filler is used to ionize the water vapor and air in the mixed air flow to form the free radicals under the action of the electron beam output by the high-frequency electron beam generator.

[0011] Furthermore, the metal foam catalytic filler is configured as a magnesium-aluminum alloy substrate with a platinum-rhodium alloy loaded on the surface.

[0012] Further, the mixing reactor also includes a nozzle; The nozzle is disposed in the mixing chamber and at a side of the metal foam catalytic filler away from the gas phase mixer, and is used for accelerating the free radicals to be output to the second mixing section.

[0013] Furthermore, the outer diameter of the cross section of the nozzle decreases along the gas discharge direction.

[0014] Furthermore, the gas-liquid delivery pipeline is connected to an air supply pipeline, a steam supply pipeline and a fresh water supply pipeline; The gas source of the air supply pipeline is the cabin PSA system; The steam source of the steam supply pipeline is a ship's boiler.

[0015] Furthermore, the output end of the air supply pipeline is also connected to the mixing reactor and the catalytic oxidation reactor, so as to provide air to the mixing reactor and the metal catalytic oxidation reaction layer for cooling.

[0016] Furthermore, the smoke delivery pipeline has two branch pipelines; One of the branch pipelines is selectively connected to the first mixing section so as to be used to increase the temperature of the first mixing section, so that the fresh water input into the first mixing section through the gas-liquid transmission pipeline can be gasified to form water vapor; Another branch pipeline is communicated with the second mixing section.

[0017] Furthermore, the output end of the catalytic oxidation reactor is connected to a clean gas discharge pipeline; A bypass pipeline is provided between the second mixing section and the clean gas exhaust pipeline.

[0018] Furthermore, the high-frequency electron beam generator is electrically connected to a high-frequency electron beam controller for controlling the on and off of the high-frequency electron beam generator; The high-frequency electron beam controller is connected to the concentration detection sensor signal on the flue gas conveying pipeline, and is also used to control the intensity of the electron beam formed by the high-frequency electron beam generator according to the concentration of methane and ammonia in the flue gas conveying pipeline; In addition, the high-frequency electron beam controller is also connected to a ship generator and an energy storage container module for supplying power.

[0019] On the other hand, the present invention also proposes a ship dual-fuel engine smoke treatment method, including the ship dual-fuel engine smoke treatment system described in the above embodiment, specifically comprising the following steps: Allowing air and water vapor to be present in the first mixing section; Controlling the high-frequency electron beam generator to output electron beams, so that air and water vapor form free radicals in the mixing reactor and output them to the second mixing section; The smoke exhaust from the ship engine is input into the second mixing section to form a mixed gas with free radicals, and then enters the catalytic oxidation reactor to sequentially pass through the metal catalytic oxidation reaction layer and the non-metal catalytic oxidation reaction layer; The mixed gas is initially catalytically oxidized by the metal catalytic oxidation reaction layer, and the metal catalytic oxidation reaction layer can absorb electron energy and heat up under electron beam irradiation during the catalytic oxidation process to accelerate the catalytic oxidation of the mixed gas; The remaining mixed gas is then catalytically oxidized again through the non-metallic catalytic oxidation reaction layer to generate and discharge clean gas.

[0020] Compared with the prior art, the present invention has at least the following beneficial effects: By setting a high-frequency electron beam generator, a mixing reactor and a gas-liquid delivery pipeline, free radicals for oxidizing methane and ammonia can be generated in the mixing reactor, and by setting a catalytic oxidation reactor, a second mixing section connected to the flue gas delivery pipeline is formed between the catalytic oxidation reactor and the mixing reactor, so that the free radicals can be preliminarily mixed and oxidized with the flue gas in the second mixing section to form a mixed gas and input into the catalytic oxidation reactor. Since the catalytic oxidation reactor has a metal catalytic oxidation reaction layer and a non-metal catalytic oxidation reaction layer arranged in sequence along the gas emission direction, and the metal catalytic oxidation reaction layer can absorb electron energy and heat up under the irradiation of the electron beam, when the mixed gas enters the catalytic oxidation reactor, the metal catalytic oxidation reaction layer can accelerate the catalysis while performing the initial catalytic oxidation of the mixed gas. The non-metal catalytic oxidation reaction layer can continuously catalytically oxidize the remaining mixed gas, and at the same time realize the shielding of the electron beam radiation to extend the service life of the downstream equipment. That is, the system adopts a three-stage treatment mechanism of free radical pre-oxidation-self-heating catalytic oxidation-continuous catalytic oxidation to achieve the function of efficiently removing unburned methane and ammonia in the engine flue gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of a ship dual-fuel engine flue gas treatment system according to an embodiment of the present invention; Figure 2 It is a partial structural schematic diagram of a smoke treatment system for a ship dual-fuel engine in one embodiment of the present invention.

[0022] Figure Number: 1. High frequency electron beam generator; 2. Mixing reactor; 21. Mixing chamber; 22. Gas phase mixer; 23. Metal foam catalytic filler; 24. Nozzle; 3. Catalytic oxidation reactor; 31. Metal catalytic oxidation reaction layer; 32. Non-metal catalytic oxidation reaction layer; 33. Mixer body; 4. Gas and liquid transmission pipeline; 41. Air supply pipeline; 42. Steam supply pipeline; 43. Fresh water supply pipeline; 5. Smoke delivery pipeline; 51. Branch pipeline; 6. The first mixing section; 7. Second mixing section; 8. Clean gas discharge pipeline; 9. Bypass pipeline; 10. High frequency electron beam controller. DETAILED DESCRIPTION

[0023] The following will be described in more detail with reference to the schematic diagram of the ship dual-fuel engine smoke treatment system and treatment method of the present invention, wherein the preferred embodiment of the present invention is shown, and it should be understood that those skilled in the art can modify the present invention described herein while still achieving the beneficial effects of the present invention. Therefore, the following description should be understood as being widely known to those skilled in the art, and not as a limitation of the present invention.

[0024] The present invention is described in more detail in the following paragraphs by way of example with reference to the accompanying drawings. The advantages and features of the present invention will become more apparent from the following description. It should be noted that the accompanying drawings are in very simplified form and are not in exact proportions, and are only used to facilitate and clearly assist in illustrating the purpose of the embodiments of the present invention.

[0025] Example 1

[0026] like Figure 1 and Figure 2 As shown, an embodiment of the present invention proposes a ship dual-fuel engine flue gas treatment system, including a high-frequency electron beam generator 1 connected in sequence along the gas emission direction, a mixing reactor 2 and a catalytic oxidation reactor 3 for cooperating with the high-frequency electron beam generator 1 to generate free radicals, a gas-liquid transmission pipeline 4 and a flue gas transmission pipeline 5.

[0027] A first mixing section 6 is formed between the high-frequency electron beam generator 1 and the mixing reactor 2, and a second mixing section 7 is formed between the mixing reactor 2 and the catalytic oxidation reactor 3. The first mixing section 6 is used to receive raw materials (such as water vapor and air) required for generating free radicals, and the second mixing section 7 is used for preliminary oxidation mixing of flue gas and free radicals to form a mixed gas.

[0028] Specifically, the gas-liquid delivery pipeline 4 is in communication with the first mixing section 6 , and is used to deliver the air and water vapor or fresh water required for the formation of the free radicals. The smoke delivery pipeline 5 is in communication with the second mixing section 7 .

[0029] The catalytic oxidation reactor 3 has a metal catalytic oxidation reaction layer 31 and a non-metal catalytic oxidation reaction layer 32 arranged in sequence along the gas discharge direction, that is, the metal catalytic oxidation reaction layer 31 and the non-metal catalytic oxidation reaction layer 32 are used for step-by-step catalysis of the mixed gas.

[0030] Specifically, the metal catalytic oxidation reaction layer 31 is used for the initial catalytic oxidation of the free radicals and the flue gas, and under the irradiation of the electron beam, it can absorb electron energy to increase the temperature, thereby accelerating the catalytic oxidation of the free radicals and the flue gas.

[0031] In the catalytic oxidation reaction, temperature is an important factor affecting the reaction rate. The metal catalytic oxidation reaction layer 31 absorbs energy and heats up under electron beam irradiation, providing more favorable conditions for the oxidation reaction between free radicals and pollutants in the flue gas (such as methane and ammonia). According to the Arrhenius equation, the reaction rate constant is exponentially related to temperature. The increase in temperature will significantly accelerate the reaction rate, so that the oxidation treatment of pollutants in the flue gas (such as methane and ammonia) can be completed in a shorter time, thereby improving the efficiency of the entire flue gas treatment system.

[0032] Furthermore, since the metal catalytic oxidation reaction layer 31 can absorb energy and heat up by itself under the irradiation of electron beams, this self-heating property avoids additional heating equipment and energy consumption. For the ship dual-fuel engine flue gas treatment system, the system complexity and energy consumption are reduced, the energy utilization efficiency is improved, and the operating cost is also reduced.

[0033] The non-metallic catalytic oxidation reaction layer 32 is used for continuous catalytic oxidation of the free radicals and the remaining flue gas, and can shield the electron beam radiation. That is, the non-metallic catalytic oxidation reaction layer 32 ensures the deep removal of pollutants (such as methane and ammonia, etc.) in the flue gas of the ship's dual-fuel engine through the dual functions of continuous catalytic oxidation and electron beam shielding, and protects the safety of downstream equipment.

[0034] The system is provided with a high-frequency electron beam generator 1, a mixing reactor 2 and a gas-liquid delivery pipeline 4, so that free radicals for oxidizing methane and ammonia can be generated in the mixing reactor 2, and a catalytic oxidation reactor 3 is provided, and a second mixing section 7 connected to the flue gas delivery pipeline 5 is formed between the catalytic oxidation reactor 3 and the mixing reactor 2, so that the free radicals can be preliminarily mixed and oxidized with the flue gas in the second mixing section 7 to form a mixed gas and input into the catalytic oxidation reactor 3. Since the catalytic oxidation reactor 3 has a metal catalytic oxidation reaction layer 31 and a non-metal catalytic oxidation reaction layer 32 sequentially arranged along the gas discharge direction, and the metal catalytic oxidation reaction layer 31 can absorb electron energy and heat up under the irradiation of the electron beam, when the mixed gas enters the catalytic oxidation reactor 3, the metal catalytic oxidation reaction layer 31 can accelerate the catalysis while performing the initial catalytic oxidation of the mixed gas. The non-metal catalytic oxidation reaction layer 32 can continuously catalytically oxidize the remaining mixed gas, and at the same time, shield the electron beam radiation to extend the service life of the downstream equipment. That is, this system achieves the function of efficiently removing unburned methane and ammonia in engine flue gas by adopting a three-stage treatment mechanism of free radical pre-oxidation-autothermal catalytic oxidation-continuous catalytic oxidation.

[0035] In this embodiment, the metal catalytic oxidation reaction layer 31 and the non-metal catalytic oxidation reaction layer 32 are further defined to enhance the catalytic oxidation effect.

[0036] Specifically, the metal catalytic oxidation reaction layer 31 is configured as a magnesium-aluminum alloy substrate loaded with CuO, A-MnO2, MoO3 and Fe3O4 as metal oxide catalysts. The multi-metal oxidant is used for synergistic catalysis to achieve the purpose of improving the catalytic oxidation effect, and the aluminum-magnesium alloy substrate is used to absorb the energy of the electron beam for heating to accelerate the catalytic oxidation of the mixed gas.

[0037] In a specific example, the mass ratio of CuO, A-MnO2, MoO3 and Fe3O4 is 1:2.5-5:1:1.

[0038] The non-metallic catalytic oxidation reaction layer 32 is configured as a ZSM-5 molecular sieve structure loaded with CuO and A-MnO2 as transition metal catalysts. Since the ZSM-5 molecular sieve structure has the characteristics of regular microporous structure and high specific surface area (providing a large number of active sites), molecular sieve effect (selective adsorption of pollutants), acidic environment stability (inhibition of sulfur poisoning), high temperature resistance (adaptation to high temperature conditions) and electron beam scattering ability (attenuation of radiation energy), it can absorb electron beam radiation while continuously catalyzing the remaining pollutants (such as methane and ammonia, etc.), achieving the dual effects of deep removal and equipment protection.

[0039] In other embodiments, the input end of the catalytic oxidation reactor 3 has a mixer body 33 for mixing the free radicals with the flue gas. That is, by providing the mixer body 33, the turbulent mixing of the free radicals and the flue gas is enhanced, the contact probability between the two is increased, and the pollutants (such as methane and ammonia, etc.) are fully pre-oxidized with the free radicals before entering the metal catalytic oxidation reaction layer 31, thereby improving the initial catalytic oxidation efficiency and providing a uniform mixed gas for the subsequent non-metallic catalytic oxidation reaction layer 32, and finally achieving the function of maximizing the pollutant removal rate and improving the stability of the catalytic reaction.

[0040] In other embodiments, a specific mixing reactor 2 is also proposed to better cooperate with the high-frequency electron beam generator 1 and the steam and air transported by the gas-liquid transport pipeline 4 to form free radicals.

[0041] Specifically, the mixing reactor 2 includes a mixing chamber 21 , a gas phase mixer 22 and a metal foam catalytic filler 23 .

[0042] The gas phase mixer 22 and the metal foam catalytic filler 23 are sequentially arranged in the mixing chamber 21 from the gas discharge direction.

[0043] The gas phase mixer 22 is used to form a uniform mixed gas flow to improve the subsequent generation effect of free radicals.

[0044] The metal foam catalytic filler 23 is used to ionize the water vapor and air in the mixed airflow to form the free radicals under the action of the electron beam output by the high-frequency electron beam generator 1. This is a prior art and will not be described in detail here.

[0045] In a specific example, the metal foam catalytic filler 23 is set as a magnesium-aluminum alloy substrate with a platinum-rhodium alloy loaded on the surface. The catalytic effect of the platinum-rhodium alloy reduces the ionization activation energy, and the high thermal conductivity of the magnesium-aluminum alloy is combined to maintain the optimal reaction temperature, which significantly improves the ionization efficiency of water vapor and air, so that a high concentration of free radicals can be generated to correspondingly improve the oxidation effect on pollutants.

[0046] In addition, the mixing reactor 2 further includes a nozzle 24, which is disposed in the mixing chamber 21 and on a side of the metal foam catalytic filler 23 away from the gas phase mixer 22, and is used to accelerate the free radicals to be output to the second mixing section 7. That is, the turbulent mixing effect of the free radicals and the flue gas can be enhanced, thereby improving the pre-oxidation efficiency.

[0047] The cross-sectional outer diameter of the nozzle 24 decreases along the gas discharge direction, that is, the accelerated ejection of free radicals is achieved through the Venturi effect.

[0048] In a further embodiment, the sources of steam, fresh water and air in the gas-liquid transmission pipeline 4 are further limited.

[0049] Specifically, the gas-liquid transmission pipeline 4 is connected to an air supply pipeline 41 , a steam supply pipeline 42 and a fresh water supply pipeline 43 .

[0050] The gas source of the air supply pipeline 41 is the ship's cabin PSA system, and the steam source of the steam supply pipeline 42 is the ship's cabin boiler, so as to achieve a stable supply of free radical raw materials.

[0051] It should be particularly noted that, in the present embodiment, since the metal foam catalytic filler 23 in the mixing reactor 2 ionizes water vapor and air to generate free radicals under high-frequency electron beam irradiation, the electron beam energy is converted into heat energy, causing the temperature to rise to 300-400°C, thereby causing the free radicals to decompose; at the same time, the metal catalytic oxidation reaction layer 31 absorbs energy under electron beam irradiation and catalyzes the oxidation reaction to release heat, and local high temperatures will also occur, causing catalysts such as CuO and A-MnO2 to sinter and become inactivated at high temperatures, resulting in a decrease in catalytic efficiency.

[0052] Therefore, in this embodiment, the output end of the air supply pipeline 41 is also connected to the mixing reactor 2 and the catalytic oxidation reactor 3 to provide air to the mixing reactor 2 and the metal catalytic oxidation reaction layer 31 for cooling. The temperature of the mixing reactor 2 and the metal catalytic oxidation reaction layer 31 is maintained within a certain range, and the temperature is dynamically controlled, so that the free radical decomposition and catalyst deactivation can be effectively avoided, and the long-term stable operation of the ship flue gas treatment system can be ensured.

[0053] In other embodiments, the flue gas conveying pipeline 5 is further limited so that when the steam output by the cabin boiler cannot meet the demand for free radical generation, that is, fresh water needs to be transported for steam generation, the fresh water can be converted into steam without consuming additional power sources, thereby achieving the purpose of energy saving and emission reduction.

[0054] Specifically, the smoke conveying pipeline 5 has two branch pipelines 51 .

[0055] One of the branch pipes 51 is selectively connected to the first mixing section 6 to be used for heating the first mixing section 6, so that the fresh water input into the first mixing section 6 through the gas-liquid transmission pipeline 4 can be gasified to form water vapor. That is, when the boiler steam is insufficient, the flue gas waste heat can be used to replace the additional power source to convert the fresh water into steam, thereby achieving the purpose of energy saving and emission reduction.

[0056] Another branch pipeline 51 is communicated with the second mixing section 7 for outputting flue gas to be mixed with free radicals.

[0057] In a further embodiment, the output end of the catalytic oxidation reactor 3 is connected to a clean gas exhaust pipeline 8, and a bypass pipeline 9 is provided between the second mixing section 7 and the clean gas exhaust pipeline 8. When the concentration of methane and ammonia in the flue gas is lower than a threshold value (such as when the engine is running at low power), the bypass pipeline 9 is activated to reduce the energy consumption of the high-frequency electron beam generator 1 and the catalytic oxidation reactor 3, thereby extending the service life of the catalyst.

[0058] In other embodiments, the high-frequency electron beam generator 1 is electrically connected to a high-frequency electron beam controller 10 for controlling the on and off of the high-frequency electron beam generator 1 .

[0059] The high-frequency electron beam controller 10 is connected to the concentration detection sensor signal on the flue gas conveying pipeline 5 , and is also used to control the intensity of the electron beam formed by the high-frequency electron beam generator 1 according to the concentration of methane and ammonia in the flue gas conveying pipeline 5 .

[0060] In addition, the high-frequency electron beam controller 10 is also connected to a ship generator and an energy storage container module for supplying power.

[0061] The high-frequency electron beam controller 10 realizes the functions of on-demand supply of electron beam energy, optimization of free radical generation efficiency and improvement of system operation stability through concentration adaptive control (real-time monitoring of methane and ammonia concentrations in flue gas and dynamic adjustment of electron beam intensity). In addition, by utilizing clean energy such as ship wind turbine power generation through energy storage modules, carbon emissions can be further reduced.

[0062] Example 2

[0063] Based on the first embodiment, the second embodiment further proposes a ship dual-fuel engine smoke treatment method, including the ship dual-fuel engine smoke treatment system described in the first embodiment, specifically including the following steps: The first mixing section 6 contains air and water vapor; Controlling the high-frequency electron beam generator 1 to output electron beams, so that air and water vapor form free radicals in the mixing reactor 2, and output them to the second mixing section 7; The smoke exhausted by the ship engine is input into the second mixing section 7 to form a mixed gas with free radicals, and then enters the catalytic oxidation reactor 3 to sequentially pass through the metal catalytic oxidation reaction layer 31 and the non-metal catalytic oxidation reaction layer 32; The mixed gas is initially catalytically oxidized by the metal catalytic oxidation reaction layer 31, and the metal catalytic oxidation reaction layer 31 can absorb electron energy and heat up under electron beam irradiation during the catalytic oxidation process to accelerate the catalytic oxidation of the mixed gas; The remaining mixed gas is then catalytically oxidized again by the non-metallic catalytic oxidation reaction layer 32 to generate and discharge clean gas.

[0064] Through the above steps, a three-stage treatment mechanism of free radical pre-oxidation - autothermal catalytic oxidation - continuous catalytic oxidation is adopted to achieve the function of efficiently removing unburned methane and ammonia in engine flue gas.

[0065] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A ship dual-fuel engine flue gas treatment system, characterized in that: It includes a high-frequency electron beam generator connected in sequence along the gas discharge direction, a mixing reactor and a catalytic oxidation reactor for generating free radicals in cooperation with the high-frequency electron beam generator, a gas-liquid conveying pipeline, and a flue gas conveying pipeline; A first mixing section is formed between the high-frequency electron beam generator and the mixing reactor, and a second mixing section is formed between the mixing reactor and the catalytic oxidation reactor; The gas-liquid delivery pipeline is in communication with the first mixing section and is used to deliver the air and water vapor or fresh water required for the formation of the free radicals; The smoke conveying pipeline is in communication with the second mixing section; The catalytic oxidation reactor is built with a metal catalytic oxidation reaction layer and a non-metal catalytic oxidation reaction layer sequentially arranged along the gas discharge direction; The metal catalytic oxidation reaction layer is used for the initial catalytic oxidation of the free radicals and the flue gas, and under the irradiation of the electron beam, it can absorb electron energy to increase the temperature, thereby accelerating the catalytic oxidation of the free radicals and the flue gas; The non-metal catalytic oxidation reaction layer is used for continuous catalytic oxidation of the free radicals and the remaining flue gas, and can shield electron beam radiation.

2. The ship dual-fuel engine flue gas treatment system according to claim 1, characterized in that: The metal catalytic oxidation reaction layer is configured as a magnesium-aluminum alloy substrate loaded with CuO, A-MnO2, MoO3 and Fe3O4 as metal oxide catalysts; The non-metal catalytic oxidation reaction layer is configured as a ZSM-5 molecular sieve structure loaded with CuO and A-MnO2 as transition metal catalysts.

3. The ship dual-fuel engine flue gas treatment system according to claim 1, characterized in that: The input end of the catalytic oxidation reactor is provided with a mixer body for mixing the free radicals with the flue gas.

4. The ship dual-fuel engine flue gas treatment system according to claim 1, characterized in that: The mixing reactor comprises a mixing chamber, a gas phase mixer and a metal foam catalytic filler; The gas phase mixer and the metal foam catalytic filler are arranged in the mixing chamber in sequence from the gas discharge direction; The gas phase mixer is used to form a uniform mixed gas flow; The metal foam catalytic filler is used to ionize the water vapor and air in the mixed air flow to form the free radicals under the action of the electron beam output by the high-frequency electron beam generator.

5. The ship dual-fuel engine flue gas treatment system according to claim 4, characterized in that: The metal foam catalytic filler is configured as a magnesium-aluminum alloy substrate with a platinum-rhodium alloy loaded on the surface.

6. The ship dual-fuel engine flue gas treatment system according to claim 4, characterized in that: The mixing reactor also includes a nozzle; The nozzle is disposed in the mixing chamber and at a side of the metal foam catalytic filler away from the gas phase mixer, and is used for accelerating the free radicals to be output to the second mixing section.

7. The ship dual-fuel engine flue gas treatment system according to claim 6, characterized in that: The outer diameter of the cross section of the nozzle decreases along the gas discharge direction.

8. The ship dual-fuel engine flue gas treatment system according to claim 1, characterized in that: The gas-liquid delivery pipeline is connected to an air supply pipeline, a steam supply pipeline and a fresh water supply pipeline; The gas source of the air supply pipeline is the cabin PSA system; The steam source of the steam supply pipeline is a ship's boiler.

9. The ship dual-fuel engine flue gas treatment system according to claim 8, characterized in that: The output end of the air supply pipeline is also connected to the mixing reactor and the catalytic oxidation reactor, and is used to provide air to the mixing reactor and the metal catalytic oxidation reaction layer for cooling.

10. The ship dual-fuel engine flue gas treatment system according to claim 1, characterized in that: The smoke delivery pipeline has two branch pipelines; One of the branch pipelines is selectively connected to the first mixing section so as to be used to increase the temperature of the first mixing section, so that the fresh water input into the first mixing section through the gas-liquid transmission pipeline can be gasified to form water vapor; Another branch pipeline is communicated with the second mixing section.

11. The ship dual-fuel engine flue gas treatment system according to claim 1, characterized in that: The output end of the catalytic oxidation reactor is connected to a clean gas discharge pipeline; A bypass pipeline is provided between the second mixing section and the clean gas exhaust pipeline.

12. The ship dual-fuel engine flue gas treatment system according to claim 1, characterized in that: The high-frequency electron beam generator is electrically connected to a high-frequency electron beam controller for controlling the opening and closing of the high-frequency electron beam generator; The high-frequency electron beam controller is connected to the concentration detection sensor signal on the flue gas conveying pipeline, and is also used to control the intensity of the electron beam formed by the high-frequency electron beam generator according to the concentration of methane and ammonia in the flue gas conveying pipeline; In addition, the high-frequency electron beam controller is also connected to a ship generator and an energy storage container module for supplying power.

13. A method for treating flue gas from a ship dual-fuel engine, characterized in that: The ship dual-fuel engine smoke treatment system according to any one of claims 1 to 12 specifically comprises the following steps: Allowing air and water vapor to be present in the first mixing section; Controlling the high-frequency electron beam generator to output electron beams, so that air and water vapor form free radicals in the mixing reactor and output them to the second mixing section; The smoke exhaust from the ship engine is input into the second mixing section to form a mixed gas with free radicals, and then enters the catalytic oxidation reactor to sequentially pass through the metal catalytic oxidation reaction layer and the non-metal catalytic oxidation reaction layer; The mixed gas is initially catalytically oxidized by the metal catalytic oxidation reaction layer, and the metal catalytic oxidation reaction layer can absorb electron energy and heat up under electron beam irradiation during the catalytic oxidation process to accelerate the catalytic oxidation of the mixed gas; The remaining mixed gas is then catalytically oxidized again through the non-metallic catalytic oxidation reaction layer to generate and discharge clean gas.

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