A Ship Dual-Fuel Engine Flue Gas Treatment System and Treatment Method

Abstract

The present invention discloses a flue gas treatment system and a treatment method for a marine dual-fuel engine, including a high-frequency electron beam generator, a mixing reactor for cooperating with the high-frequency electron beam generator to generate free radicals, a catalytic oxidation reactor, a gas-liquid delivery pipeline, and a flue gas delivery pipeline, which are sequentially connected along the gas discharge direction; 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 communicated with the first mixing section; the flue gas delivery pipeline is communicated with the second mixing section; wherein, a metal catalytic oxidation reaction layer and a non-metal catalytic oxidation reaction layer are sequentially arranged in the catalytic oxidation reactor along the gas discharge direction. The present invention adopts a three-stage treatment mechanism of free radical pre-oxidation, self-heating catalytic oxidation, and continuous catalytic oxidation to achieve efficient removal of unburned methane and ammonia in the engine flue gas.

Description

Technical Field

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

[0002] With the continuous improvement of the global awareness of environmental protection, the impact of ship exhaust gas emissions on the atmospheric environment has attracted 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 utilization efficiency and reduce operating costs. However, during the combustion process, dual-fuel engines produce complex exhaust gas components, including a large amount of nitrogen oxides (NO x ), sulfur oxides (SO x ), particulate matter (PM), as well as pollutants such as methane (CH4) and ammonia (NH3). These pollutants not only cause serious pollution to the atmospheric environment, triggering environmental problems such as acid rain and smog, but also pose a hazard to human health.

[0003] Catalytic oxidation technology is an effective exhaust gas treatment method. Through the action of a catalyst, 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, when existing catalytic oxidation technology is used to treat the exhaust gas of ship dual-fuel engines, some problems still exist.

[0004] On the one hand, existing catalysts have deficiencies in terms of activity and selectivity, and it is difficult to efficiently treat multiple pollutants simultaneously. For example, the catalytic oxidation efficiency of pollutants such as methane and ammonia is relatively low, requiring a relatively high reaction temperature and a long reaction time, resulting in increased system energy consumption and low treatment efficiency. On the other hand, during the traditional catalytic oxidation reaction process, the activity of the catalyst is easily affected by impurities and moisture in the exhaust gas, leading to catalyst deactivation and the need for frequent catalyst replacement, increasing the operating cost.

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

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

[0007] To solve the above technical problems, the present invention provides a ship dual-fuel engine flue gas treatment system, including a high-frequency electron beam generator, a mixing reactor for cooperating with the high-frequency electron beam generator to generate free radicals, a catalytic oxidation reactor, a gas-liquid delivery pipeline, and a flue gas delivery pipeline, which are connected in sequence along the gas emission direction;

[0008] 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;

[0009] The gas-liquid delivery pipeline is connected to the first mixing section and is used to deliver the air and water vapor or air and fresh water required for the formation of the free radicals;

[0010] The flue gas delivery pipeline is connected to the second mixing section;

[0011] Wherein, the catalytic oxidation reactor is internally provided with a metal catalytic oxidation reaction layer and a non-metal catalytic oxidation reaction layer arranged in sequence along the gas discharge direction;

[0012] The metal catalytic oxidation reaction layer is used for the primary catalytic oxidation of the free radicals and the flue gas, and under the action of electron beam irradiation, it can absorb the electron energy to increase the temperature, thereby accelerating the catalytic oxidation of the free radicals and the flue gas;

[0013] The non-metal catalytic oxidation reaction layer is used for the continuous catalytic oxidation of the free radicals and the remaining flue gas, and can shield the electron beam radiation.

[0014] Further, the metal catalytic oxidation reaction layer is set as a magnesium-aluminum alloy base material loaded with CuO, α-MnO2, MoO3, and Fe3O4 as metal oxide catalysts;

[0015] The non-metal catalytic oxidation reaction layer is set as a ZSM-5 molecular sieve structure loaded with CuO and α-MnO2 as transition metal catalysts.

[0016] Further, the input end of the catalytic oxidation reactor has a mixer body for mixing the free radicals and the flue gas.

[0017] Further, the mixing reactor includes a mixing cavity, a gas-phase mixer, and a metal foam catalytic filler;

[0018] The gas-phase mixer and the metal foam catalytic filler are sequentially arranged in the mixing cavity from the gas discharge direction;

[0019] The gas-phase mixer is used to form a uniform mixed gas flow;

[0020] The metal foam catalytic filler is used to ionize the water vapor and air in the mixed gas flow to form the free radicals under the action of the electron beam output by the high-frequency electron beam generator.

[0021] Further, the metal foam catalytic filler is set as a magnesium-aluminum alloy base material with a platinum-rhodium alloy loaded on the surface.

[0022] Further, the mixing reactor further includes a nozzle;

[0023] The nozzle is arranged in the mixing cavity and on the side of the metal foam catalytic packing away from the gas mixer, and is used to accelerate the output of the free radicals to the second mixing section.

[0024] Further, the outer diameter of the cross-section of the nozzle decreases along the gas discharge direction.

[0025] Further, the gas-liquid delivery pipeline is connected with an air supply pipeline, a steam supply pipeline and a fresh water supply pipeline;

[0026] The gas source of the air supply pipeline is the ship's cabin PSA system;

[0027] The steam source of the steam supply pipeline is the ship's cabin boiler.

[0028] Further, the output end of the air supply pipeline is also connected with the mixing reactor and the catalytic oxidation reactor, and is used to supply air to the mixing reactor and the metal catalytic oxidation reaction layer for cooling.

[0029] Further, the flue gas delivery pipeline has two branch pipelines;

[0030] One of the branch pipelines is selectively communicated with the first mixing section, and can be used for heating the first mixing section, so that the fresh water input into the first mixing section by the gas-liquid delivery pipeline can be vaporized to form water vapor;

[0031] The other branch pipeline is communicated with the second mixing section.

[0032] Further, the output end of the catalytic oxidation reactor is connected with a clean gas discharge pipeline;

[0033] A bypass pipeline is arranged between the second mixing section and the clean gas discharge pipeline.

[0034] Further, the high-frequency electron beam generator is electrically connected with a high-frequency electron beam controller for controlling the opening and closing of the high-frequency electron beam generator;

[0035] Among them, the high-frequency electron beam controller is signal-connected with the concentration detection sensor on the flue gas delivery pipeline, and is also used to control the intensity of the electron beam formed by the high-frequency electron beam generator according to the concentrations of methane and ammonia in the flue gas delivery pipeline;

[0036] And, the high-frequency electron beam controller is also connected with the ship's generator and the energy storage container module for power supply.

[0037] On the other hand, the present invention also proposes a method for treating the flue gas of a marine dual-fuel engine, including the marine dual-fuel engine flue gas treatment system described in the above embodiments, specifically including the following steps:

[0038] Make the first mixing section have air and water vapor;

[0039] Control the high-frequency electron beam generator to output an electron beam, so that free radicals are formed in the mixing reactor from the air and water vapor, and output to the second mixing section;

[0040] Input the flue gas discharged from the marine engine into the second mixing section to form a mixed gas with the free radicals, and enter the catalytic oxidation reactor to sequentially pass through the metal catalytic oxidation reaction layer and the non-metal catalytic oxidation reaction layer;

[0041] The metal catalytic oxidation reaction layer initially catalyzes and oxidizes the mixed gas, and the metal catalytic oxidation reaction layer can absorb the electron energy and heat up under the irradiation of the electron beam during the catalytic oxidation process to accelerate the catalytic oxidation of the mixed gas;

[0042] Then, the remaining mixed gas is further catalytically oxidized by the non-metal catalytic oxidation reaction layer to generate and discharge clean gas.

[0043] Compared with the prior art, the present invention has at least the following beneficial effects:

[0044] By setting up 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 up a catalytic oxidation reactor, and 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 it 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 discharge direction, and the metal catalytic oxidation reaction layer can absorb the electron energy and heat up under the action of electron beam irradiation, when the mixed gas enters the catalytic oxidation reactor, the metal catalytic oxidation reaction layer can not only initially catalyze and oxidize the mixed gas, but also accelerate the catalysis. The non-metal catalytic oxidation reaction layer can continuously catalyze and oxidize the remaining mixed gas, while realizing the shielding of electron beam radiation to extend the service life of downstream equipment. That is, this system realizes the function of efficiently removing unburned methane and ammonia in the engine flue gas through a three-stage treatment mechanism of free radical pre-oxidation-self-heating catalytic oxidation-continuous catalytic oxidation. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a schematic structural diagram of a marine dual-fuel engine flue gas treatment system in an embodiment of the present invention;

[0046] Figure 2 This is a schematic diagram of the partial structure of the flue gas treatment system for a ship's dual-fuel engine in an embodiment of the present invention.

[0047] Reference numerals in the drawings:

[0048] 1. High-frequency electron beam generator;

[0049] 2. Mixing reactor; 21. Mixing cavity; 22. Gas-phase mixer; 23. Metal foam catalytic filler; 24. Nozzle;

[0050] 3. Catalytic oxidation reactor; 31. Metal catalytic oxidation reaction layer; 32. Non-metal catalytic oxidation reaction layer; 33. Mixer body;

[0051] 4. Gas-liquid delivery pipeline; 41. Air supply pipeline; 42. Steam supply pipeline; 43. Fresh water supply pipeline;

[0052] 5. Flue gas delivery pipeline; 51. Branch pipeline;

[0053] 6. First mixing section;

[0054] 7. Second mixing section;

[0055] 8. Clean gas discharge pipeline;

[0056] 9. Bypass pipeline;

[0057] 10. High-frequency electron beam controller. Detailed implementation manners

[0058] The ship's dual-fuel engine flue gas treatment system and treatment method of the present invention will be described in more detail below with reference to the schematic diagrams, which show the preferred embodiments of the present invention. It should be understood that those skilled in the art can modify the present invention described herein while still achieving the advantageous effects of the present invention. Therefore, the following description should be understood as a broad guidance for those skilled in the art and not as a limitation to the present invention.

[0059] In the following paragraphs, the present invention will be described more specifically by way of example with reference to the accompanying drawings. The advantages and features of the present invention will be clearer according to the following description. It should be noted that the drawings are all in a very simplified form and use non-precise scales, only for the purpose of conveniently and clearly assisting in explaining the embodiments of the present invention.

[0060] Embodiment 1

[0061] As Figure 1 and Figure 2As shown in the figure, an embodiment of the present invention provides a flue gas treatment system for a marine dual-fuel engine, which includes a high-frequency electron beam generator 1, a mixing reactor 2 for cooperating with the high-frequency electron beam generator 1 to generate free radicals, a catalytic oxidation reactor 3, a gas-liquid conveying pipeline 4, and a flue gas conveying pipeline 5, which are connected in sequence along the gas discharge direction.

[0062] 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 the raw materials (such as water vapor and air) required for generating free radicals, while the second mixing section 7 is used for the preliminary oxidation mixing of flue gas and free radicals to form a mixed gas.

[0063] Specifically, the gas-liquid conveying pipeline 4 is communicated with the first mixing section 6 and is used to convey the air and water vapor or air and fresh water required for forming free radicals. The flue gas conveying pipeline 5 is communicated with the second mixing section 7.

[0064] The catalytic oxidation reactor 3 is internally provided with 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 the step-by-step catalysis of the mixed gas.

[0065] Specifically, the metal catalytic oxidation reaction layer 31 is used for the primary catalytic oxidation of free radicals and flue gas, and under the action of electron beam irradiation, it can absorb electron energy to increase the temperature, thereby accelerating the catalytic oxidation of free radicals and flue gas.

[0066] In the catalytic oxidation reaction, temperature is an important factor affecting the reaction rate. The metal catalytic oxidation reaction layer 31 absorbs energy and increases the temperature under electron beam irradiation, providing more favorable conditions for the oxidation reaction of free radicals and pollutants (such as methane and ammonia, etc.) in the flue gas. According to the Arrhenius equation, the reaction rate constant has an exponential relationship with temperature. An increase in temperature will significantly accelerate the reaction rate, so that the oxidation treatment of pollutants (such as methane and ammonia, etc.) in the flue gas can be completed in a shorter time, improving the efficiency of the entire flue gas treatment system.

[0067] Moreover, since the metal catalytic oxidation reaction layer 31 can absorb energy and increase the temperature by itself under the action of electron beam irradiation, this self-heating and temperature-rising characteristic avoids additional heating equipment and energy consumption. For the flue gas treatment system of a marine dual-fuel engine, it reduces the complexity and energy consumption of the system, improves the energy utilization efficiency, and also reduces the operation cost.

[0068] The non-metal catalytic oxidation reaction layer 32 is used for the continuous catalytic oxidation of the free radicals and the remaining flue gas, and can shield the electron beam radiation. That is, the non-metal 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 and protects the safety of downstream equipment through the dual functions of continuous catalytic oxidation and electron beam shielding.

[0069] By setting up the high-frequency electron beam generator 1, the mixing reactor 2 and the gas-liquid delivery pipeline 4 in this system, free radicals for oxidizing methane and ammonia can be generated in the mixing reactor 2. And by setting up the catalytic oxidation reactor 3, 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 be 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 arranged in sequence along the gas discharge direction, and the metal catalytic oxidation reaction layer 31 can absorb the electron energy and heat up under the action of electron beam irradiation, when the mixed gas enters the catalytic oxidation reactor 3, the metal catalytic oxidation reaction layer 31 can not only conduct primary catalytic oxidation on the mixed gas but also play an accelerating catalytic effect. The non-metal catalytic oxidation reaction layer 32 can continuously catalytically oxidize the remaining mixed gas and at the same time achieve the shielding of electron beam radiation to extend the service life of downstream equipment. That is, this system realizes the function of efficiently removing unburned methane and ammonia in the engine flue gas through the three-stage treatment mechanism of free radical pre-oxidation - self-heating catalytic oxidation - continuous catalytic oxidation.

[0070] In this embodiment, the metal catalytic oxidation reaction layer 31 and the non-metal catalytic oxidation reaction layer 32 are further defined to improve the catalytic oxidation effect.

[0071] Specifically, the metal catalytic oxidation reaction layer 31 is set as a magnesium-aluminum alloy substrate loaded with CuO, α-MnO2, MoO3 and Fe3O4 as metal oxide catalysts. Multiple metal oxidants are used for synergistic catalysis to achieve the purpose of improving the catalytic oxidation effect, and the characteristic that the aluminum-magnesium alloy substrate can absorb the electron beam energy for heating up is utilized to accelerate the catalytic oxidation of the mixed gas.

[0072] In a specific example, the mass ratio of CuO, α-MnO2, MoO3 and Fe3O4 is 1:2.5 - 5:1:1.

[0073] The non-metal catalytic oxidation reaction layer 32 is configured as a ZSM-5 molecular sieve structure loaded with CuO and α-MnO2 as transition metal catalysts. Due to the characteristics of the ZSM-5 molecular sieve structure, such as regular microporous structure and high specific surface area (providing a large number of active sites), molecular sieve effect (selectively adsorbing pollutants), acidic environment stability (inhibiting sulfur poisoning), high temperature resistance (adapting to high temperature working conditions), and electron beam scattering ability (attenuating radiation energy), it can not only continuously catalyze the remaining pollutants (such as methane and ammonia, etc.) but also absorb electron beam radiation while realizing the dual functions of deep removal and equipment protection.

[0074] In other embodiments, the input end of the catalytic oxidation reactor 3 has a mixer body 33 for mixing the free radicals and the flue gas. That is, by setting 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 it is ensured that 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 primary catalytic oxidation efficiency and providing a uniform mixed gas for the subsequent non-metal catalytic oxidation reaction layer 32, ultimately realizing the functions of maximizing the pollutant removal rate and improving the catalytic reaction stability.

[0075] In other embodiments, a specific mixing reactor 2 is also proposed to better cooperate with the high-frequency electron beam generator 1 and the vapor and air transported by the gas-liquid delivery pipeline 4 to form free radicals.

[0076] Specifically, the mixing reactor 2 includes a mixing cavity 21, a gas-phase mixer 22, and a metal foam catalytic filler 23.

[0077] Among them, the gas-phase mixer 22 and the metal foam catalytic filler 23 are sequentially arranged in the mixing cavity 21 from the gas discharge direction.

[0078] The gas-phase mixer 22 is used to form a uniform mixed gas flow and improve the subsequent generation effect of free radicals.

[0079] The metal foam catalytic filler 23 is used to ionize the water vapor and air in the mixed gas flow to form the free radicals under the action of the electron beam output by the high-frequency electron beam generator 1. This is prior art, so it will not be elaborated here.

[0080] In a specific example, the metal foam catalytic filler 23 is configured as a magnesium-aluminum alloy substrate with a platinum-rhodium alloy loaded on its surface. By the catalytic action of the platinum-rhodium alloy, the ionization activation energy is reduced, and combined with the high thermal conductivity of the magnesium-aluminum alloy, the optimal reaction temperature is maintained, significantly improving the ionization efficiency of water vapor and air. Therefore, high-concentration free radicals can be generated to correspondingly improve the oxidation effect on pollutants.

[0081] In addition, the hybrid reactor 2 further includes a nozzle 24 which is arranged in the mixing cavity 21 and on the side of the metal foam catalytic packing 23 away from the gas-phase mixer 22, and is used for accelerating the output of the free radicals to the second mixing section 7. That is, it can enhance the turbulent mixing effect of the free radicals and the flue gas and improve the pre-oxidation efficiency.

[0082] Wherein, the outer diameter of the cross-section of the nozzle 24 decreases along the gas discharge direction, that is, the accelerated ejection of the free radicals is realized through the Venturi effect.

[0083] In a further embodiment, the sources of the vapor, fresh water and air in the gas-liquid delivery pipeline 4 are further defined.

[0084] Specifically, the gas-liquid delivery pipeline 4 is connected with an air supply pipeline 41, a vapor supply pipeline 42 and a fresh water supply pipeline 43.

[0085] Wherein, the gas source of the air supply pipeline 41 is the cabin PSA system, and the vapor source of the vapor supply pipeline 42 is the cabin boiler, so as to realize the stable supply of the free radical raw materials.

[0086] It should be particularly noted that in this embodiment, when the metal foam catalytic packing 23 in the hybrid reactor 2 ionizes water vapor and air under high-frequency electron beam irradiation to generate free radicals, the temperature will rise to 300-400 °C due to the conversion of the electron beam energy into heat, which will further cause the decomposition of the free radicals; at the same time, the metal catalytic oxidation reaction layer 31 absorbs energy under electron beam irradiation and catalyzes the exothermic oxidation reaction, and local high temperature will also occur, resulting in the sintering inactivation of catalysts such as CuO and α-MnO2 at high temperature, leading to a reduction in the catalytic efficiency.

[0087] Therefore, in this embodiment, the output end of the air supply pipeline 41 is also connected to the hybrid reactor 2 and the catalytic oxidation reactor 3, and is used to supply air to the hybrid reactor 2 and the metal catalytic oxidation reaction layer 31 for cooling. The temperatures of the hybrid reactor 2 and the metal catalytic oxidation reaction layer 31 are maintained within a certain range, realizing the dynamic regulation of the temperature, so as to effectively avoid the decomposition of free radicals and the inactivation of catalysts, and ensure the long-term stable operation of the ship flue gas treatment system.

[0088] In other embodiments, the flue gas delivery pipeline 5 is further defined, so that when the vapor output by the cabin boiler cannot meet the free radical generation requirement, that is, when fresh water needs to be transported to generate vapor, it is also possible to convert the fresh water into vapor without consuming an additional power source, achieving the purpose of energy conservation and emission reduction.

[0089] Specifically, the flue gas delivery pipeline 5 has two branch pipelines 51.

[0090] One of the branch pipelines 51 is selectively communicated with the first mixing section 6 so as to be capable of heating the first mixing section 6, enabling the fresh water input into the first mixing section 6 through the gas-liquid delivery pipeline 4 to be vaporized to form water vapor. That is, when the boiler steam is insufficient, the waste heat of the flue gas can be utilized to replace the additional power source to convert fresh water into steam, thereby achieving the purpose of energy conservation and emission reduction.

[0091] The other branch pipeline 51 is communicated with the second mixing section 7 for outputting flue gas to be mixed with free radicals.

[0092] In a further embodiment, a clean gas discharge pipeline 8 is connected to the output end of the catalytic oxidation reactor 3, and a bypass pipeline 9 is arranged between the second mixing section 7 and the clean gas discharge pipeline 8. When the concentrations of methane and ammonia in the flue gas are lower than the threshold (such as when the engine is operating at low power), enabling the bypass pipeline 9 can reduce the energy consumption of the high-frequency electron beam generator 1 and the catalytic oxidation reactor 3 and extend the service life of the catalyst.

[0093] In other embodiments, the high-frequency electron beam generator 1 is electrically connected to a high-frequency electron beam controller 10 for controlling the opening and closing of the high-frequency electron beam generator 1.

[0094] Wherein, the high-frequency electron beam controller 10 is in signal connection with the concentration detection sensor on the flue gas delivery pipeline 5 and is also used for controlling the intensity of the electron beam formed by the high-frequency electron beam generator 1 according to the concentrations of methane and ammonia in the flue gas delivery pipeline 5.

[0095] Moreover, the high-frequency electron beam controller 10 is also connected to a ship generator and an energy storage container module for power supply.

[0096] The high-frequency electron beam controller 10 realizes the functions of supplying electron beam energy on demand, optimizing the free radical generation efficiency, and improving the system operation stability through concentration adaptive regulation (real-time monitoring of the concentrations of methane and ammonia in the flue gas and dynamically adjusting the electron beam intensity). Moreover, by using clean energy such as ship wind turbine power generation through the energy storage module, the carbon emission can be further reduced.

[0097] Embodiment 2

[0098] Based on Embodiment 1, this second embodiment also proposes a method for treating the flue gas of a ship dual-fuel engine, including the ship dual-fuel engine flue gas treatment system described in Embodiment 1, and specifically includes the following steps:

[0099] Make the first mixing section 6 have air and water vapor;

[0100] Control the electron beam output by the high-frequency electron beam generator 1 to form free radicals from air and water vapor in the mixing reactor 2, and output them to the second mixing section 7;

[0101] Input the flue gas discharged from the ship engine into the second mixing section 7 to form a mixed gas with free radicals, and enter 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;

[0102] The metal catalytic oxidation reaction layer 31 conducts primary catalytic oxidation on the mixed gas, and the metal catalytic oxidation reaction layer 31 can absorb electron energy and heat up under electron beam irradiation during catalytic oxidation to accelerate the catalytic oxidation of the mixed gas;

[0103] Then, the non-metal catalytic oxidation reaction layer 32 conducts secondary catalytic oxidation on the remaining mixed gas to generate and discharge clean gas.

[0104] Through the above steps, a three-stage treatment mechanism of free radical pre-oxidation - self-heating catalytic oxidation - continuous catalytic oxidation is adopted to achieve the function of efficiently removing unburned methane and ammonia in the engine flue gas.

[0105] Obviously, those skilled in the art can make various modifications and variations 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 equivalent technologies, the present invention also intends to include these modifications and variations.

Claims

1. A flue gas treatment system for a marine dual-fuel engine, characterized in that, It includes a high-frequency electron beam generator, a mixing reactor for cooperating with the high-frequency electron beam generator to generate free radicals, a catalytic oxidation reactor, a gas-liquid delivery pipeline, and a flue gas delivery pipeline, which are connected in sequence along the gas discharge direction; 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 communicated with the first mixing section for delivering air and water vapor or air and fresh water required for forming the free radicals; The flue gas delivery 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 arranged in sequence along the gas discharge direction; The metal catalytic oxidation reaction layer is used for the primary catalytic oxidation of the free radicals and the flue gas, and under the action of electron beam irradiation, it can absorb electron energy to heat up, thereby accelerating the catalytic oxidation of the free radicals and the flue gas; The non-metal catalytic oxidation reaction layer is used for the 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 set as a magnesium-aluminum alloy base material loaded with CuO, α-MnO2, MoO3, and Fe3O4 as metal oxide catalysts; The non-metal catalytic oxidation reaction layer is set as a ZSM-5 molecular sieve structure loaded with CuO and α-MnO2 as transition metal catalysts.

3. The flue gas treatment system for a marine dual-fuel engine according to claim 1, wherein, The input end of the catalytic oxidation reactor has a mixer body for mixing the free radicals and the flue gas.

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

5. The flue gas treatment system for a marine dual-fuel engine according to claim 4, wherein The metal foam catalytic filler is set as a magnesium-aluminum alloy base material with a platinum-rhodium alloy loaded on the surface.

6. The flue gas treatment system for a marine dual-fuel engine according to claim 4, characterized in that, The mixing reactor further includes a nozzle; The nozzle is arranged in the mixing cavity and on the side of the metal foam catalytic filler away from the gas-phase mixer, and is used for accelerating the output of the free radicals to the second mixing section.

7. The flue gas treatment system for a marine dual-fuel engine 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 flue gas treatment system for a marine dual-fuel engine according to claim 1, characterized in that The gas-liquid delivery pipeline is connected with 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 the cabin 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 with the mixing reactor and the catalytic oxidation reactor for providing air to the mixing reactor and the metal catalytic oxidation reaction layer for cooling; 10. The flue gas treatment system for a marine dual-fuel engine according to claim 1, wherein, The flue gas delivery pipeline has two branch pipelines; One of the branch pipelines is selectively communicated with the first mixing section to be capable of heating the first mixing section, so that the fresh water input into the first mixing section through the gas-liquid conveying pipeline can be vaporized to form water vapor; The other branch pipeline is communicated with the second mixing section.

11. The flue gas treatment system for a marine dual-fuel engine according to claim 1, characterized in that, A clean gas discharge pipeline is connected to the output end of the catalytic oxidation reactor; A bypass pipeline is arranged between the second mixing section and the clean gas discharge 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 with a high-frequency electron beam controller for controlling the opening and closing of the high-frequency electron beam generator; Wherein, the high-frequency electron beam controller is in signal connection with a concentration detection sensor on the flue gas conveying pipeline, and is further used for controlling the intensity of the electron beam formed by the high-frequency electron beam generator according to the concentrations of methane and ammonia in the flue gas conveying pipeline; And, the high-frequency electron beam controller is further connected with a ship generator and an energy storage container module for power supply.

13. A method for treating flue gas of a ship's dual-fuel engine, characterized in that, Including the ship dual-fuel engine flue gas treatment system according to any one of claims 1-12, specifically comprising the following steps: Make the first mixing section have air and water vapor; Control the high-frequency electron beam generator to output an electron beam, so that air and water vapor form free radicals in the mixing reactor and are output to the second mixing section; Input the flue gas discharged from the ship engine into the second mixing section to form a mixed gas with free radicals and enter the catalytic oxidation reactor to sequentially pass through a metal catalytic oxidation reaction layer and a non-metal catalytic oxidation reaction layer; Primarily catalytically oxidize the mixed gas through the metal catalytic oxidation reaction layer, and the metal catalytic oxidation reaction layer can absorb electron energy and heat up under the irradiation of the electron beam during the catalytic oxidation process to accelerate the catalytic oxidation of the mixed gas; Then, catalytically oxidize the remaining mixed gas again through the non-metal catalytic oxidation reaction layer to generate and discharge clean gas.

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