Ship dual-fuel engine flue gas oxidation methanol removal system and method

Abstract

The invention discloses a ship dual-fuel engine flue gas oxidation methanol removal system and method, and relates to the technical field of flue gas treatment, the system comprises: a mixer comprising a flue gas inlet and a flue gas outlet; the first reactor is internally provided with a first catalyst packing layer, two ends of the first catalyst packing layer are respectively provided with a first input end and a first output end, and the first input end is communicated with the smoke outlet; the heat exchange device comprises a heat exchange device feed port, a heat exchange device discharge port, a circulating medium inlet and a circulating medium outlet, and the heat exchange device feed port is communicated with the first output end; the washing device is internally provided with a washing liquid spraying device, the side wall of the washing device is provided with a washing device feed port, the top of the washing device is provided with a methanol-removed flue gas outlet, the bottom of the washing device is provided with a washing liquid outlet, the washing device feed port is communicated with the heat exchange device discharge port, and the washing liquid outlet is communicated with the flue gas inlet and the circulating medium inlet. The system and the method can efficiently decompose escaping methanol in the flue gas.

Description

Technical Field

[0001] The present application relates to the technical field of flue gas treatment, and in particular to a system and method for oxidative removal of methanol from flue gas of a ship dual-fuel engine. Background Art

[0002] With increasingly stringent environmental protection requirements and adjustments to the energy structure, the shipping industry has gradually adopted dual-fuel engines, such as the mixed use of liquefied natural gas (LNG) and traditional fuels, to reduce greenhouse gas emissions. Although dual-fuel engines can significantly reduce carbon dioxide and nitrogen oxide emissions during operation, there is still a certain amount of methanol in the flue gas, and methanol is a toxic substance. If it is discharged into the atmosphere, it will seriously pollute the environment and harm the health of the crew.

[0003] Therefore, how to efficiently decompose the escaped methanol in the flue gas has become a technical problem that needs to be solved urgently in the shipping industry. Summary of the invention

[0004] The technical problem solved by the technical solution of this application is how to efficiently decompose the escaped methanol in the flue gas.

[0005] In order to solve the above technical problems, the technical solution of the present application provides a system for oxidative demethanolation of flue gas of a ship dual-fuel engine, the system comprising: a mixer, the mixer comprising a smoke inlet for methanol-containing smoke and an oxidizing solution to enter, and a smoke outlet for outputting mixed steam containing oxidizing steam and methanol-containing smoke; at least one first reactor, each of the first reactors is provided with a first catalyst packing layer inside, and the two ends of the first catalyst packing layer are respectively provided with a first input end and a first output end, wherein the first input end is connected to the smoke outlet; a heat exchange device, comprising a heat exchange device feed inlet, a heat exchange device discharge port, a circulating medium inlet and a circulating medium outlet, wherein the heat exchange device feed inlet is connected to the first output end; a washing device, wherein a washing liquid spraying device is provided inside, a washing device feed inlet is provided on the side wall, a demethanolated smoke outlet is provided on the top, and a washing liquid outlet is provided on the bottom, wherein the washing liquid spraying device is higher than the washing device feed inlet, and the washing device feed inlet is connected to the heat exchange device discharge port, and the washing liquid outlet is connected to the smoke inlet and the circulating medium inlet.

[0006] In some embodiments, an arc generator is further disposed inside each of the first reactors; and the oxidizing solution includes hydrogen peroxide.

[0007] In some embodiments, the first catalyst packing layer comprises a metal organic framework-based catalyst, and the metal organic framework-based catalyst comprises aluminum, manganese dioxide, copper oxide, and vanadium pentoxide in a mass ratio of 3:1:1:2.

[0008] In some embodiments, the interior of the washing device is further provided with: a gas-liquid contact packing layer, located below the washing liquid spraying device and above the feeding port of the washing device; and a demisting assembly, located above the washing liquid spraying device.

[0009] In some embodiments, the system also includes: at least one second reactor, each of the second reactors is provided with a second catalyst packing layer inside, and the two ends of the second catalyst packing layer are respectively provided with a second input end and a second output end, wherein the second input end is connected to the washing liquid outlet and the circulating medium outlet, and the second output end is connected to the washing liquid spraying device.

[0010] In some embodiments, the system further comprises: a flue gas washing circulation pump, whose input end is connected to the washing liquid outlet, and whose output end is connected to the smoke inlet and the circulating medium inlet.

[0011] In some embodiments, the system further includes: a liquid replenishing device, connected to the washing device, for replenishing the oxidizing solution into the interior of the washing device.

[0012] In some embodiments, the fluid replenishment device includes: a fluid storage device for storing an oxidizing solution; and a fluid replenishment pump, an input end of which is connected to the fluid storage device, and an output end of which is connected to the washing device.

[0013] In some embodiments, the system further comprises: a pH detection device, disposed at the outlet of the washing liquid.

[0014] The present application also provides a method for oxidative demethanolation of flue gas from a ship dual-fuel engine, which adopts the oxidative demethanolation system for flue gas from a ship dual-fuel engine as described above, and the method comprises: inputting methanol-containing flue gas and an oxidizing solution into a mixer, wherein the heat of the methanol-containing flue gas vaporizes the oxidizing solution to form oxidizing steam, so that the mixer outputs a mixed steam containing oxidizing steam and methanol-containing flue gas; inputting the mixed steam containing oxidizing steam and methanol-containing flue gas into a first reactor, wherein methanol and oxidizing steam undergo a catalytic oxidation reaction, and outputting the obtained material from the first reactor; cooling the material output from the first reactor to a target temperature in a heat exchange device; conveying the material at the target temperature to the interior of a washing device, washing it with a washing liquid, and outputting the demethanolated flue gas and the washing liquid respectively; conveying the washing liquid output from the washing device to the smoke inlet of the mixer and the circulating medium inlet of the heat exchange device.

[0015] Compared with the prior art, the system and method for oxidative removal of methanol from flue gas of a ship dual-fuel engine of the technical solution of the present application has the following beneficial effects: The system and method for oxidative demethanolation of flue gas of a ship dual-fuel engine of the present application can achieve gas-vapor contact of mixed steam containing oxidative steam and flue gas containing methanol, so the contact probability of methanol and oxide is relatively large, with high oxidative decomposition efficiency, and can also reduce the amount of oxidative solution, thereby achieving efficient decomposition of escaped methanol in the flue gas. At the same time, the waste heat of the flue gas can directly vaporize the oxidative solution without the need for an external heat source, which can not only avoid the energy consumption of external heating, but also reduce the manufacturing cost and maintenance difficulty of the equipment. At the same time, the washing liquid outlet of the washing device is connected to the smoke inlet of the mixer and the circulating medium inlet of the heat exchange device, which can realize the recycling of the washing liquid, improve the resource utilization efficiency of the system, waste liquid treatment cost and energy consumption, and achieve a double improvement in economic benefits and environmental benefits.

[0016] Furthermore, an arc generator is arranged inside the first reactor, and hydrogen peroxide is used as an oxidizing solution. The arc generated by the arc generator can decompose hydrogen peroxide into oxygen on the catalyst surface. The decomposed oxygen and residual oxygen in the flue gas can produce ozone with strong oxidizing properties in the arc, which can significantly improve the oxidative decomposition ability of methanol, thereby improving the methanol removal rate. At the same time, compared with the electric heating temperature raising catalytic process, the power consumption of the electrocatalytic hydrogen peroxide oxidation process of the present application is significantly reduced.

[0017] Furthermore, making the first catalyst packing layer include aluminum, manganese dioxide, copper oxide and vanadium pentoxide in a specific mass ratio can significantly improve the methanol removal effect.

[0018] Furthermore, a second reactor is provided, and a second input end of the second reactor is connected to a washing liquid outlet of the washing device and a circulating medium outlet of the heat exchange device, and a second output end of the second reactor is connected to a washing liquid spraying device of the washing device. This not only can realize the recycling of the washing liquid output by the washing device and the high-temperature circulating medium output by the heat exchange device, but also can enhance the oxidation capacity of the oxidizing solution, thereby reducing the system energy consumption, the washing liquid replenishment cost and the amount of oxidizing solution used. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The following drawings describe in detail the exemplary embodiments disclosed in this application. The same reference numerals represent similar structures in several views of the drawings. Those skilled in the art will understand that these embodiments are non-limiting, exemplary embodiments, and the drawings are only used for the purpose of illustration and description, and are not intended to limit the scope of this application. Other embodiments may also accomplish the inventive intent in this application. It should be understood that the drawings are not drawn to scale. Among them: Figure 1 This is a schematic structural diagram of a flue gas oxidation and methanol removal system for a ship dual-fuel engine according to an embodiment of the present application; Figure 2This is a schematic structural diagram of another system for oxidative removal of methanol from flue gas of a ship dual-fuel engine according to an embodiment of the present application; The meanings of the reference numerals are as follows: 1-mixer; 2-first reactor; 3-heat exchange device; 4-washing device; 41-washing liquid spraying device; 42-gas-liquid contact packing layer; 43-demist assembly; 5-smoke washing circulation pump; 6-second reactor; 71-liquid storage device; 72-liquid replenishing pump; 8-pH detection device. DETAILED DESCRIPTION

[0020] The following description provides specific application scenarios and requirements of the present application, with the purpose of enabling those skilled in the art to make and use the contents of the present application. Various local modifications to the disclosed embodiments are obvious to those skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the present application.

[0021] The embodiment of the present application provides a flue gas oxidation and methanol removal system for a ship dual-fuel engine, which can efficiently decompose escaped methanol in the flue gas.

[0022] refer to Figure 1 The flue gas oxidation and demethanolation system of a ship dual-fuel engine according to an embodiment of the present application comprises: a mixer 1, at least one first reactor 2, a heat exchange device 3 and a scrubbing device 4. The mixer 1 is used to input methanol-containing flue gas and an oxidizing solution, and output a mixed steam containing oxidizing steam and methanol-containing flue gas. The mixer 1 comprises a smoke inlet and a smoke outlet, and the methanol-containing flue gas and the oxidizing solution enter the mixer 1 from the smoke inlet, and gas-liquid mixing is completed in the mixer 1. Since the temperature of the exhaust flue gas of a ship dual-fuel engine is usually high, generally at 200°C~300°C, the oxidizing solution is heated and vaporized during the mixing process to form oxidizing steam, which is output at the smoke outlet together with the methanol-containing flue gas.

[0023] The first reactor 2 is used to input a mixed steam containing oxidizing steam and flue gas containing methanol, and output the material after the catalytic oxidation reaction. A first catalyst packing layer is provided inside the first reactor 2, and the methanol and oxidizing steam in the flue gas undergo a catalytic oxidation reaction under the action of the catalyst, and the methanol is oxidized into formaldehyde. The two ends of the first catalyst packing layer are respectively provided with a first input end and a first output end, wherein the first input end is connected to the smoke outlet of the mixer 1, and is used to input a mixed steam containing oxidizing steam and flue gas containing methanol, and the first output end is used to output the material after the catalytic oxidation reaction.

[0024] When the ship engine is running at a low speed, the flue gas temperature is relatively low, which will increase the amount of escaped methanol. In order to speed up the reaction rate and improve the removal rate of methanol, an arc generator can be set inside the first reactor 2, and the oxidizing solution used includes hydrogen peroxide. In this way, electrocatalysis and catalyst catalysis are achieved to accelerate the oxidation reaction rate. The arc generated by the arc generator causes hydrogen peroxide to decompose oxygen on the catalyst surface, and the decomposed oxygen and residual oxygen in the flue gas produce ozone in the arc. The extremely strong oxidizing property of ozone can oxidize methanol at room temperature. In the presence of a catalyst, ozone oxidizes methanol into formaldehyde, formic acid, carbon dioxide, water and other substances. The specific position of the arc generator inside the first reactor 2 is not limited, as long as the arc generated can decompose hydrogen peroxide into oxygen and oxidize oxygen into ozone.

[0025] In some embodiments, the first catalyst filler layer includes a metal organic framework-based catalyst, and the metal organic framework-based catalyst includes a metal organic framework and a metal oxide attached to the surface of the metal organic framework. By utilizing the conductivity of the metal organic framework and the catalytic effect of the metal oxide, hydrogen peroxide can be decomposed into oxygen and water under the action of the catalyst, and under the action of the electric arc, the oxygen forms ozone in the gap of the catalyst.

[0026] In some preferred embodiments, the metal organic framework-based catalyst comprises aluminum, manganese dioxide, copper oxide and vanadium pentoxide in a mass ratio of 3:1:1:2. Aluminum, as a metal organic framework, forms an oxide film on its surface during the oxidation reaction, thereby preventing further oxidation to the inside. When the components are in this mass ratio, an excellent methanol removal rate is achieved.

[0027] In some embodiments, the metal organic framework-based catalyst is prepared by the following method: aluminum, manganese dioxide, copper oxide, and vanadium pentoxide are mixed in a mass ratio of 3:1:1:2 to form a foam alloy. The foam alloy is cut into a desired shape and filled into the first reactor 2 to form the first catalyst packing layer.

[0028] The heat exchange device 3 is used to cool the material output from the first reactor 2 to the target temperature and output it. The heat exchange device 3 includes a heat exchange device feed port, a heat exchange device discharge port, a circulating medium inlet and a circulating medium outlet, wherein the heat exchange device feed port is connected to the first output end of the first reactor 2 for inputting the material, and the heat exchange device discharge port is used to output the material at the target temperature. The circulating medium inlet is used to input the low-temperature circulating medium for cooling the material, and the circulating medium outlet is used to output the high-temperature circulating medium after absorbing heat. The heat exchange device 3 can be a conventional heat exchanger.

[0029] The washing device 4 is used to wash the material cooled to the target temperature to separate the methanol-free flue gas. A washing liquid spraying device 41 is provided inside the washing device 4. The washing liquid spraying device 41 is used to spray the washing liquid, for example, it can be a plurality of nozzles. Methanol, formaldehyde, formic acid and other substances that may exist in the material can be dissolved in the washing liquid. The washing liquid can be an aqueous solution, preferably hydrogen peroxide.

[0030] The side wall of the washing device 4 has a washing device feed port, the top has a de-methanol flue gas outlet for outputting the de-methanol flue gas, and the bottom has a washing liquid outlet. The washing liquid spray device 41 is higher than the washing device feed port to form a gas-liquid countercurrent to improve the washing effect. The washing device feed port is connected to the heat exchange device discharge port of the heat exchange device 3 to allow materials to enter the interior of the washing device 4. The washing liquid outlet is connected to the smoke inlet of the mixer 1 to provide an oxidizing solution to the mixer 1. The washing liquid outlet is also connected to the circulating medium inlet of the heat exchange device 3, and provides a low-temperature circulating medium to the heat exchange device 3. Thereby, the recycling of the washing liquid is achieved.

[0031] In some specific embodiments, Figure 2 As shown, the flue gas oxidation demethanolization system of the ship dual-fuel engine of the embodiment of the present application also includes a flue gas washing circulation pump 5, the input end of the flue gas washing circulation pump 5 is connected to the washing liquid outlet of the washing device 4, and the output end of the flue gas washing circulation pump 5 is connected to the smoke inlet of the mixer 1 and the circulating medium inlet of the heat exchange device 3.

[0032] In some specific embodiments, a flue gas flow meter may be provided at the smoke inlet of the mixer 1. The flue gas washing circulation pump 5 is controlled by the flue gas flow signal of the flue gas flow meter, thereby controlling the flow rate of the washing liquid output from the washing liquid outlet of the washing device 4. When the flue gas flow rate increases, the flue gas washing circulation pump 5 is controlled so that the flow rate of the washing liquid output from the washing liquid outlet also increases accordingly.

[0033] Continue to refer Figure 2 The washing device 4 is also provided with a gas-liquid contact packing layer 42 and a demisting assembly 43, wherein the gas-liquid contact packing layer 42 is located below the washing liquid spraying device 41 and higher than the washing device feed port of the washing device 4, so as to increase the gas-liquid contact area and improve the washing effect. The specific material and structure of the gas-liquid contact packing layer 42 are not limited, and a conventional structure can be used. The demisting assembly 43 is used to dehydrate the flue gas, and its specific structure is not required, as long as it can play a dehydrating role.

[0034] The marine dual-fuel engine flue gas oxidation and demethanolation system of the embodiment of the present application further includes at least one second reactor 6, the washing liquid output from the washing liquid outlet of the washing device 4 and the high-temperature circulating medium output from the circulating medium outlet of the heat exchange device 3 are input into the second reactor 6, and the formaldehyde contained therein is catalytically oxidized into formic acid, which can enhance the oxidizing ability of the oxidizing solution, and then output to the washing liquid spraying device 41. The second reactor 6 can not only recycle the washing liquid output from the washing device 4 and the high-temperature circulating medium output from the heat exchange device 3, but also enhance the oxidizing ability of the oxidizing solution.

[0035] A second catalyst packing layer is provided inside each second reactor 6, and the catalyst of the second catalyst packing layer is selected from oxides of metals such as copper and manganese, vanadium pentoxide, titanium dioxide, etc., and is used to catalytically oxidize formaldehyde into formic acid. A second input end and a second output end are provided at both ends of the second catalyst packing layer, wherein the second input end is connected to the washing liquid outlet of the washing device 4 and the circulating medium outlet of the heat exchange device 3, and the second output end is connected to the washing liquid spraying device 41.

[0036] In some embodiments, the ship dual-fuel engine flue gas oxidation demethanol system further includes: a liquid replenishing device, which is connected to the washing device 4 and is used to replenish the oxidizing solution to the inside of the washing device 4. In some specific embodiments, the liquid replenishing device includes a liquid storage device 71 and a liquid replenishing pump 72, the liquid storage device 71 is used to store the oxidizing solution, the input end of the liquid replenishing pump 72 is connected to the liquid storage device 71, and the output end of the liquid replenishing pump 72 is connected to the washing device 4.

[0037] In some embodiments, the ship dual-fuel engine flue gas oxidation demethanol system further includes: a pH detection device 8, which is arranged at the washing liquid outlet of the washing device 4. In some embodiments, a pH detection device can also be arranged between the second output end of the second reactor 6 and the washing liquid spraying device 41. When it is detected that the pH value of the washing liquid output from the washing liquid outlet of the washing device 4 or the washing liquid delivered by the second reactor 6 to the washing liquid spraying device 41 increases, it means that the oxidizing property of the oxidizing solution in the system decreases, and the oxidizing solution in the liquid storage device 71 needs to be extracted by the liquid replenishing pump 72 and delivered to the inside of the washing device 4 to replenish new oxidizing solution.

[0038] The embodiment of the present application does not specifically limit the number of the first reactor 2 and the second reactor 6 and the mass concentration of the hydrogen peroxide, which can be adjusted according to the actual situation of methanol removal. When the methanol content in the flue gas is high and the methanol removal rate is low, it can be adjusted by increasing the mass concentration of hydrogen peroxide, increasing the number of stages of the first reactor 2, and increasing the number of stages of the second reactor 6. In some specific embodiments, the mass concentration of hydrogen peroxide is 20% to 30%, the number of stages of the first reactor 2 is two, and the number of stages of the second reactor 6 is three.

[0039] The following combination Figure 2 The overall operation process of the ship dual-fuel engine flue gas oxidation and demethanolization system according to the embodiment of the present application is further described.

[0040] The methanol-containing flue gas (200℃~300℃) emitted by the ship's dual-fuel engine and the oxidizing solution are mixed in the mixer 1. Due to the high temperature of the methanol-containing flue gas, the oxidizing solution is vaporized, and the mixed steam containing the oxidizing steam and the methanol-containing flue gas enters the first reactor 2. A catalytic oxidation reaction occurs in the first reactor 2 to convert methanol into formaldehyde, or an electrocatalytic oxidation reaction occurs in the first reactor 2 to convert methanol into formaldehyde and formic acid. The material output from the first reactor 2 enters the heat exchange device 3, and its temperature is reduced to the target temperature (such as 160℃). The cooled material enters the washing device 4, and after gas-liquid countercurrent washing, the formaldehyde, formic acid, and residual methanol that may exist in the material are dissolved in the washing liquid, and the methanol-free flue gas is discharged from the washing device 4. The washing liquid enters the bottom of the washing device 4 for buffering, and then is sent to the heat exchange device 3 for heating (130°C) through the flue gas washing circulation pump 5. The high-temperature washing liquid (that is, the high-temperature circulating medium output by the heat exchange device 3) from the heat exchange device 3 enters the second reactor 6, catalytically oxidizes formaldehyde into formic acid, so that the oxidizing ability of the oxidizing solution is enhanced, and then outputs to the washing liquid spraying device 41. At the same time, the flue gas washing circulation pump 5 also transports the washing liquid output by the washing device 4 to the mixer 1. The flue gas washing circulation pump 5 can also directly transport the washing liquid output by the washing device 4 to the second reactor 6. The above process is circulated continuously, and finally the formic acid is oxidized into water and carbon dioxide. In the above process, the pH value of the washing liquid output from the washing liquid outlet of the washing device 4 is monitored by the pH detection device 8. When the pH value is detected to increase, the oxidizing solution in the liquid storage device 71 is drawn by the liquid replenishment pump 72 for replenishment.

[0041] Use this application respectively Figure 2The shown ship dual-fuel engine flue gas oxidation demethanol system (referred to as electrocatalytic hydrogen peroxide oxidation process) and electric heating temperature catalytic process are used to remove methanol from flue gas containing methanol, and the two processes are compared, and the results are shown in Table 1. Among them, the first catalyst packing layer and the arc generator are simultaneously set in the first reactor of the ship dual-fuel engine flue gas oxidation demethanol system of the present application, and the material of the first catalyst packing layer is aluminum, manganese dioxide, copper oxide and vanadium pentoxide with a mass ratio of 3:1:1:2, and the oxidizing solution is hydrogen peroxide with a mass concentration of 25%. The electric heating temperature catalytic process refers to heating the flue gas to a suitable reaction temperature, relying on oxygen in the air for catalytic oxidation to achieve the purpose of demethanol.

[0042] Table 1 Comparison results of the two processes project Electrocatalytic hydrogen peroxide oxidation process Electric heating catalytic process power consumption 0.002Kw~0.0026Kw / Nm3 flue gas 0.025Kw~0.04Kw / Nm3 flue gas Other consumption <![CDATA[10 mL H2O2 / Nm3 flue gas]]> 0.1Nm3 air / Nm3 flue gas Since the flue gas power is large and the flue gas volume is thousands of cubic meters per hour, the power consumption is very high to electrically heat the flue gas to the target reaction temperature. However, the electrocatalytic hydrogen peroxide oxidation process mainly converts the oxygen produced by a small amount of hydrogen peroxide into ozone, which then oxidizes the methanol in the flue gas. The amount of hydrogen peroxide can be added according to the methanol content. Generally, the mass fraction of methanol escaping in the flue gas is about 5%~7%. Therefore, the power consumption of the electrocatalytic hydrogen peroxide oxidation process is very low, which can achieve real energy saving.

[0043] use Figure 2 The methanol removal system shown in the figure uses an electrocatalytic hydrogen peroxide oxidation process to remove methanol, wherein the temperature of the methanol-containing flue gas is 300°C, the oxidizing solution is hydrogen peroxide with a mass concentration of 25%, and the material components of the second catalyst packing layer are manganese dioxide, copper oxide, and vanadium pentoxide in a mass ratio of 1:1:2, and the methanol removal rates of different first catalyst packing layers are compared. The only difference between different first catalyst packing layers is the material composition. Methanol removal rate = (C 初始甲醇 -C 处理后甲醇 ) / C 初始甲醇 ×100%,C 初始甲醇 represents the methanol concentration in the initial flue gas, C 处理后甲醇 Represents the concentration of methanol contained in the treated flue gas. These two concentration values ​​can be measured at the corresponding positions using a concentration meter. The results are shown in Table 2.

[0044] Table 2 Methanol removal rate results of different first catalyst packing layers Material composition of the first catalyst packing layer Quality Ratio Methanol removal rate / % Aluminum, manganese dioxide, copper oxide, vanadium pentoxide 3:1:1:2 98.5 Aluminum, titanium dioxide, copper oxide, vanadium pentoxide 3:1:1:2 98.7 Aluminum, manganese dioxide, vanadium pentoxide 3:1.5:2.5 91.2 Aluminum, manganese dioxide, copper oxide 3:2:2 88.5 Manganese dioxide, copper oxide, vanadium pentoxide 2:3:3 93.7 It can be seen from Table 2 that when the material of the first catalyst packing layer is a specific component of aluminum, manganese dioxide, copper oxide and vanadium pentoxide in a mass ratio of 3:1:1:2, the methanol removal effect is most significant.

[0045] The embodiment of the present application also provides a method for oxidative removal of methanol from flue gas of a ship dual-fuel engine, which uses the above-mentioned system for oxidative removal of methanol from flue gas of a ship dual-fuel engine, and the method comprises the following steps: S1: inputting methanol-containing flue gas and an oxidizing solution into a mixer, wherein the heat of the methanol-containing flue gas vaporizes the oxidizing solution to form oxidizing steam, so that the mixer outputs mixed steam containing the oxidizing steam and the methanol-containing flue gas; S2: inputting the mixed steam containing the oxidizing steam and the flue gas containing methanol into the first reactor, wherein the methanol and the oxidizing steam undergo a catalytic oxidation reaction, and outputting the obtained material from the first reactor; S3: Cooling the material output from the first reactor to a target temperature in a heat exchange device; S4: transporting the material at the target temperature to the interior of the washing device, washing it with a washing liquid, and outputting the methanol-removed flue gas and the washing liquid respectively; S5: transporting the washing liquid outputted from the washing device to the smoke inlet of the mixer and the circulating medium inlet of the heat exchange device.

[0046] In some embodiments, the method further includes step S6-1: transporting the high-temperature circulating medium output from the circulating medium outlet of the heat exchange device to a second reactor, catalytically oxidizing the formaldehyde contained in the high-temperature circulating medium into formic acid, and outputting it to the washing liquid spraying device of the washing device.

[0047] In some embodiments, the method further includes step S6-2: conveying the washing liquid output from the washing device to a second reactor, catalytically oxidizing the formaldehyde contained in the washing liquid into formic acid, and outputting it to a washing liquid spraying device of the washing device.

[0048] In some embodiments, the method further comprises: when it is detected that the pH value of the washing liquid outputted from the washing liquid outlet of the washing device increases, replenishing the oxidizing solution into the washing device.

[0049] It should be noted that different embodiments may produce different beneficial effects. In different embodiments, the beneficial effects that may be produced may be any one or a combination of the above, or any other beneficial effects that may be obtained.

[0050] The basic concepts have been described above. Obviously, for those skilled in the art, the above detailed disclosure is only for example and does not constitute a limitation of this specification. Although not explicitly stated here, those skilled in the art may make various modifications, improvements and corrections to this application. Such modifications, improvements and corrections are suggested in this specification, so such modifications, improvements and corrections still belong to the spirit and scope of the exemplary embodiments of this application.

[0051] It should be noted that in the description of this application, unless otherwise clearly specified and limited, the terms "installation", "connection", "connected", "connection", and "fixation" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a rotational connection or a sliding connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood in combination with specific circumstances.

[0052] In addition, when terms such as "first", "second", and "third" are used in the specification of this application to describe various features, these terms are only used to distinguish these features and cannot be understood as indicating or implying the relationship between the features, the relative importance, or implicitly indicating the number of features indicated.

[0053] In addition, the present specification describes exemplary embodiments by reference to idealized exemplary cross-sectional views and / or plan views and / or stereograms. Therefore, differences from the illustrated shapes due to, for example, manufacturing techniques and / or tolerances are foreseeable. Therefore, the exemplary embodiments should not be interpreted as being limited to the shapes of the regions shown herein, but should include deviations in shapes caused by, for example, manufacturing. Therefore, the regions shown in the figures are schematic in nature, and their shapes are not intended to illustrate the actual shapes of the regions of the device nor to limit the scope of the exemplary embodiments.

[0054] At the same time, the present application uses specific words to describe the embodiments of this specification. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more in different positions in the present application does not necessarily refer to the same embodiment. In addition, some features, structures or characteristics in one or more embodiments of the present application can be appropriately combined.

[0055] Similarly, it should be noted that in order to simplify the description disclosed in this application and thus help understand one or more embodiments of the invention, in the above description of the embodiments of the application, multiple features are sometimes combined into one embodiment, figure or description thereof. In fact, the features of the embodiment are less than all the features of the single embodiment disclosed above.

[0056] Finally, it should be understood that the embodiments described in this application are only used to illustrate the principles of the embodiments of the present application. Other variations may also fall within the scope of the present application. Therefore, as an example and not a limitation, the alternative configurations of the embodiments of the present application may be considered to be consistent with the teachings of the present application. Accordingly, the embodiments of the present application are not limited to the embodiments explicitly introduced and described in the present application.

Claims

1. A ship dual-fuel engine flue gas oxidation and methanol removal system, characterized in that: include: A mixer (1), the mixer (1) comprising a smoke inlet for allowing methanol-containing flue gas and an oxidizing solution to enter, and a smoke outlet for outputting mixed steam containing oxidizing steam and methanol-containing flue gas; At least one first reactor (2), each of the first reactors (2) being provided with a first catalyst packing layer inside, and the first catalyst packing layer being provided with a first input end and a first output end at two ends thereof, wherein the first input end is in communication with the smoke outlet; A heat exchange device (3), comprising a heat exchange device feed port, a heat exchange device discharge port, a circulating medium inlet and a circulating medium outlet, wherein the heat exchange device feed port is connected to the first output end; A washing device (4) is provided with a washing liquid spraying device (41) inside, a washing device feed inlet is provided on the side wall, a demethanol flue gas outlet is provided on the top, and a washing liquid outlet is provided on the bottom, wherein the washing liquid spraying device (41) is higher than the washing device feed inlet, the washing device feed inlet is connected to the heat exchange device discharge port, and the washing liquid outlet is connected to the flue gas inlet and the circulating medium inlet.

2. The ship dual-fuel engine flue gas oxidation and methanol removal system according to claim 1, characterized in that: An arc generator is also arranged inside each of the first reactors; the oxidizing solution includes hydrogen peroxide.

3. The ship dual-fuel engine flue gas oxidation and methanol removal system according to claim 2, characterized in that: The first catalyst packing layer includes a metal organic framework-based catalyst, and the metal organic framework-based catalyst includes aluminum, manganese dioxide, copper oxide and vanadium pentoxide in a mass ratio of 3:1:1:

2.

4. The ship dual-fuel engine flue gas oxidation and methanol removal system according to claim 1, characterized in that: The washing device is also provided with: A gas-liquid contact filler layer (42) is located below the washing liquid spraying device (41) and above the feed inlet of the washing device; The demisting assembly (43) is located above the washing liquid spraying device (41).

5. The ship dual-fuel engine flue gas oxidation and methanol removal system according to claim 1, characterized in that: The system further comprises: at least one second reactor (6), each second reactor (6) being provided with a second catalyst packing layer inside, and having a second input end and a second output end respectively provided at two ends of the second catalyst packing layer, wherein the second input end is connected to the washing liquid outlet and the circulating medium outlet, and the second output end is connected to the washing liquid spraying device (41).

6. The ship dual-fuel engine flue gas oxidation and methanol removal system according to claim 1, characterized in that: The system further comprises: a flue gas washing circulation pump (5), the input end of which is connected to the washing liquid outlet, and the output end of which is connected to the smoke inlet and the circulating medium inlet.

7. The ship dual-fuel engine flue gas oxidation and methanol removal system according to any one of claims 1 to 6, characterized in that: The system further comprises: a liquid replenishing device, which is in communication with the washing device (4) and is used to replenish an oxidizing solution into the interior of the washing device (4).

8. The ship dual-fuel engine flue gas oxidation and methanol removal system according to claim 7, characterized in that: The fluid replenishment device comprises: A liquid storage device (71), used for storing an oxidizing solution; A liquid replenishing pump (72), whose input end is connected to the liquid storage device (71) and whose output end is connected to the washing device (4).

9. The ship dual-fuel engine flue gas oxidation and methanol removal system according to claim 7, characterized in that: The system further comprises: a pH detection device (8) arranged at the outlet of the washing liquid.

10. A method for oxidative removal of methanol from flue gas of a ship dual-fuel engine, characterized in that: The marine dual-fuel engine flue gas oxidation and methanol removal system according to any one of claims 1 to 9 is used, and the method comprises: Inputting methanol-containing flue gas and an oxidizing solution into a mixer, wherein the heat of the methanol-containing flue gas vaporizes the oxidizing solution to form oxidizing steam, so that the mixer outputs mixed steam containing the oxidizing steam and the methanol-containing flue gas; Inputting the mixed steam containing the oxidizing steam and the flue gas containing methanol into the first reactor, wherein the methanol and the oxidizing steam undergo a catalytic oxidation reaction, and outputting the obtained material from the first reactor; Cooling the material output from the first reactor to a target temperature in a heat exchange device; The material at the target temperature is transported to the interior of the washing device, washed with washing liquid, and the methanol-removed flue gas and the washing liquid are outputted separately; The washing liquid outputted from the washing device is transported to the smoke inlet of the mixer and the circulating medium inlet of the heat exchange device.

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