A method and system for recovering water and carbon dioxide from a net-zero fuel combustion furnace

Abstract

A method and system for recovering water and carbon dioxide for a net-zero fuel combustion furnace belongs to the field of carbon dioxide recovery in flue gas. The fuel gas is desulfurized to form net-zero fuel gas, which is then fed into the combustion furnace for full combustion. The flue gas generated by the combustion furnace is treated with waste heat to form low-temperature flue gas. The low-temperature flue gas is subjected to gas-water separation treatment to separate condensed water and dehumidified flue gas. The dehumidified flue gas is fed into a carbon dioxide capture device. The recovered carbon dioxide is compressed, stored, and utilized. The recovered water is processed together with the condensed water to form pure water. The present invention forms net-zero fuel gas by pre-desulfurization of the fuel gas, and then recovers the waste heat of the flue gas after combustion to form low-temperature flue gas and separates gas and water. This not only separates most of the water vapor, but also further reduces the temperature of the flue gas, allowing it to be better absorbed by solid amine in the carbon dioxide capture device, thereby improving the recovery rate and recovery efficiency of carbon dioxide and water.

Description

Technical Field

[0001] The present invention relates to the field of water and carbon dioxide recovery in combustion furnace flue gas, and in particular to a method and system for recovering water and carbon dioxide in a net zero fuel combustion furnace. Background Art

[0002] Industrial waste gas (also known as flue gas) produced by oxygen-enriched combustion contains a high concentration of carbon dioxide. By concentrating and recycling it, carbon emissions can be further reduced and carbon dioxide can be turned into treasure, which has extremely high economic value.

[0003] However, the concentration and recovery of carbon dioxide in flue gas has high requirements for the carbon dioxide source. It is necessary to first treat the water vapor, dust (mainly solid fuel) and sulfide in the exhaust gas, especially sulfide. Otherwise, it may cause problems such as cumulative poisoning of the adsorbent, device failure, and low recovery rate during the carbon dioxide concentration process.

[0004] In the existing technology, different treatment methods are selected according to the difference in fuel composition:

[0005] For liquid fuel or solid fuel, the flue gas needs to be cooled and then desulfurized and denitrified, and then the carbon dioxide is concentrated;

[0006] For gas fuel, desulfurization and denitrification can be carried out after the flue gas is cooled after combustion, or desulfurization can be carried out before combustion.

[0007] For the treatment of flue gas after combustion, in addition to conventional treatment such as desulfurization, denitrification, and dust removal, the flue gas needs to be cooled to a certain temperature before carbon dioxide can be concentrated. The overall process is relatively complex and costly.

[0008] As for the pre-desulfurization of fuel gas before combustion, the existing desulfurization method can remove most of the inorganic sulfur, but the removal effect of the organic sulfur present in the gas fuel is very poor. Therefore, a large amount of sulfur oxides will still be produced after combustion, and subsequent flue gas desulfurization equipment will still be needed for treatment. Summary of the Invention

[0009] The purpose of the present invention is to provide a method and system for recovering water and carbon dioxide from a net-zero fuel combustion furnace. Net-zero fuel gas is formed by pre-desulfurization of the fuel gas, and then the waste heat of the flue gas after combustion is recovered to form low-temperature flue gas and separate the gas and water. This not only separates most of the water vapor, but also further reduces the temperature of the flue gas, allowing it to be better absorbed by solid amine in the carbon dioxide capture device, thereby improving the recovery rate and recovery efficiency of carbon dioxide and water.

[0010] The technical solution adopted by the present invention to achieve the above technical objectives is: a method for recovering water and carbon dioxide from a net zero fuel combustion furnace, comprising the following steps:

[0011] 1) Desulfurize the fuel gas to form net-zero fuel gas, and then feed the net-zero fuel gas and oxygen-enriched air into the combustion furnace for complete combustion;

[0012] 2) The flue gas generated by the combustion furnace is processed through waste heat recovery to form low-temperature flue gas. During this process, the waste heat of the flue gas is used to preheat the net-zero fuel gas;

[0013] 3) The low-temperature flue gas in step 2) is subjected to gas-water separation treatment to separate condensed water and dehumidified flue gas;

[0014] 4) The dehumidified flue gas from step 3) is fed into a carbon dioxide capture device, the recovered carbon dioxide is compressed, stored and utilized, and the recovered water is processed together with the condensed water from step 3) to form pure water.

[0015] As an optimization solution for the above-mentioned method for recovering water and carbon dioxide from the net zero fuel burner, the sulfur content of the net zero fuel gas in step 1) is not greater than 1 ppm.

[0016] As another optimization scheme for the above-mentioned method for recovering water and carbon dioxide from the net zero fuel combustion furnace, the temperature of the low-temperature flue gas in step 2) is 50-60°C.

[0017] A water and carbon dioxide recovery system for a net-zero fuel combustion furnace includes a desulfurization device, a flue gas waste heat recovery device, a gas-water separator and a carbon dioxide capture device, wherein the fuel gas first enters the desulfurization device for desulfurization treatment to form net-zero fuel gas, which is then sent to the combustion furnace for combustion, and the high-temperature flue gas generated is passed into the flue gas waste heat recovery device, and heat exchanged with the net-zero fuel gas to form low-temperature flue gas, which is then sent to the gas-water separator to separate condensed water and dehumidified flue gas. The dehumidified flue gas is then passed into the carbon dioxide capture device, and the separated carbon dioxide is compressed and stored, and the separated water is processed together with the condensed water generated in the gas-water separator to form pure water. The flue gas waste heat recovery device includes multiple sets of plate heat exchanger units connected in series, each of which is connected in series. The plate heat exchanger unit includes a closed shell with a hollow interior, in which a number of closed hollow plate-like members are arranged in parallel, a fuel gas flow channel is formed inside each hollow plate-like member, and the two ends of all the hollow plate-like members are respectively connected to the fuel gas exhaust collection pipe and the fuel gas inlet collection pipe, and flue gas flow channels are formed on both sides of each hollow plate-like member, and all the flue gas flow channels are connected to the flue gas inlet pipe and the flue gas exhaust pipe at both ends of the shell. Along the direction of flue gas flow, the flue gas exhaust pipe of the upper group of plate heat exchanger units is connected to the flue gas inlet pipe of the next group of plate heat exchanger units, and along the direction of fuel gas flow, the fuel gas exhaust collection pipe of the upper group of plate heat exchanger units is connected to the fuel gas inlet collection pipe of the next group of plate heat exchanger units.

[0018] As another optimization solution for the above-mentioned net zero fuel combustion furnace water and carbon dioxide recovery system, the carbon dioxide capture device is a solid amine adsorption carbon dioxide capture device.

[0019] As another optimization scheme for the water and carbon dioxide recovery system of the net zero fuel combustion furnace, the desulfurization device includes a first-level desulfurization zone that is hollow and closed inside, a central liquid storage pipe is provided in the central area of ​​the first-level desulfurization zone, and an annular gas-liquid mixing zone and a peripheral liquid storage zone are alternately provided around the central liquid storage pipe. The tops of the central liquid storage pipe and the peripheral liquid storage zone are closed and an annular gas distribution pipe is provided. The bottoms of the central liquid storage pipe and the peripheral liquid storage zone have absorbent injection channels; an annular partition is provided in the gas-liquid mixing zone parallel to its side wall, and the annular partition separates the gas-liquid mixing zone from the liquid storage zone. The internal space is divided into a liquid suction mixing chamber close to the central liquid storage pipe and an overflow absorption chamber away from the central liquid storage pipe, wherein the top of the liquid suction mixing chamber is connected to the annular gas distribution pipe, and the upper and middle part of the liquid suction mixing chamber is provided with a liquid suction area connected to the central liquid storage pipe or the peripheral liquid storage area. The liquid suction area is composed of densely distributed liquid suction holes. The fuel gas in the annular gas distribution pipe enters the liquid suction mixing chamber at a high speed and generates negative pressure, and absorbs the absorbent through the liquid suction holes to fully mix and react with the fuel gas, and enters the overflow absorption chamber along the channel connected to the overflow absorption chamber at the bottom, and realizes gas-liquid separation at the top of the overflow absorption chamber;

[0020] An absorption liquid buffer zone and an absorption liquid convergence zone are respectively provided at the bottom and top of the primary desulfurization zone. The annular gas distribution pipe is connected to the fuel gas pipeline. The central liquid storage pipe and the absorbent injection channel at the bottom of the peripheral liquid storage area are both connected to the absorption liquid buffer zone; the top of the overflow absorption cavity is connected to the absorption liquid convergence zone, and a primary absorption liquid discharge pipe is provided on one side of the absorption liquid convergence zone, and the top is connected to the fuel gas convergence coil, thereby realizing gas-liquid separation.

[0021] As another optimization scheme for the water and carbon dioxide recovery system of the above-mentioned net zero fuel combustion furnace, the fuel gas convergence coil is connected to the secondary desulfurization zone above the primary desulfurization zone, so that the fuel gas is subjected to secondary desulfurization in the secondary desulfurization zone. The middle, bottom and top of the secondary desulfurization zone are respectively provided with a secondary absorption liquid injection pipe, a secondary absorption liquid discharge pipe and a purified gas discharge pipe, and the secondary absorption liquid injection pipe sprays the desulfurization absorption liquid downward from the middle of the secondary desulfurization zone through a number of atomizing nozzles.

[0022] As another optimization scheme for the water and carbon dioxide recovery system of the above-mentioned net zero fuel combustion furnace, the fuel gas collection coil is located at the bottom of the secondary desulfurization zone, and the fuel gas is delivered into the secondary desulfurization zone in the form of microbubbles with a diameter not exceeding 1 mm through a number of microbubble generators located at the bottom of the secondary desulfurization zone. After reacting with the absorption liquid in the secondary desulfurization zone, the fuel gas is discharged through the purified gas exhaust pipe at the top.

[0023] As another optimization solution for the above-mentioned net zero fuel burner water and carbon dioxide recovery system, a plurality of ultrasonic generators are installed in the secondary desulfurization zone.

[0024] As another optimization solution for the water and carbon dioxide recovery system of the net zero fuel combustion furnace, the liquid suction hole is a conical hole, and the end with a smaller diameter is connected to the liquid suction mixing chamber.

[0025] As another optimization solution for the above-mentioned net zero fuel combustion furnace water and carbon dioxide recovery system, the liquid absorption area is a multi-section hole distribution area spaced apart along the height direction, and a solid part is formed between adjacent hole distribution areas.

[0026] As another optimization solution for the water and carbon dioxide recovery system of the above-mentioned net zero fuel combustion furnace, at least one flow breaking plate is horizontally arranged in the liquid suction mixing chamber, and a fluid channel is formed between the edge of the flow breaking plate and the inner wall of the liquid suction mixing chamber.

[0027] As another optimization solution for the water and carbon dioxide recovery system of the net zero fuel combustion furnace, the surface of the flow breaking plate is densely covered with through holes.

[0028] As another optimization solution for the water and carbon dioxide recovery system of the above-mentioned net zero fuel combustion furnace, the two sides of the flow breakers are fixed to the two side walls of the liquid suction mixing chamber by a plurality of tension springs so that the flow breakers vibrate at high frequency under the impact of the high-speed gas-liquid mixture.

[0029] The net zero fuel mentioned in the present invention refers to fuel gas with a sulfur content of no more than 1 ppm after desulfurization.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1) This invention pre-desulfurizes the fuel gas to form net-zero fuel gas, then recovers the waste heat from the flue gas after combustion to form low-temperature flue gas and separates the gas and water. This not only separates most of the water vapor, but also further reduces the flue gas temperature, allowing it to be better absorbed by the solid amine in the carbon dioxide capture device, thereby improving the recovery rate and efficiency of carbon dioxide and water.

[0032] 2) To reduce the flue gas temperature as quickly as possible to meet the requirements of subsequent steam-water separation and carbon dioxide adsorption, the flue gas waste heat recovery device of the present invention uses multiple sets of plate heat exchanger units connected in series. The number of series connections can be adjusted according to actual conditions, reducing the final flue gas temperature to 50-60°C, facilitating subsequent processing. Multiple sets of hollow plate-like members form fuel flow channels within the plate heat exchanger units, with flue gas flow channels formed on both sides of the hollow plate-like members. This allows for sufficient contact and heat exchange between the flue gas and the fuel gas, improving heat exchange efficiency.

[0033] 3) In order to maximize the absorption rate of organic sulfur in the fuel gas, the desulfurization device of the present invention is provided with a first-level desulfurization zone of a special structure. A central liquid storage pipe is provided at the center of the closed shell, and then an annular gas-liquid mixing zone and a peripheral liquid storage zone are alternately provided around the central liquid storage pipe. Absorption liquid is injected from top to bottom into the central liquid storage pipe and the peripheral liquid storage zone, and then the gas-liquid mixing zone is divided into a liquid absorption mixing chamber close to the central liquid storage pipe and an overflow absorption chamber away from the central liquid storage pipe. The bottoms of the two chambers are connected, and then the fuel gas is allowed to enter the top of the liquid absorption mixing chamber at a high speed, thereby generating a negative pressure in the liquid absorption mixing chamber, and then the absorption liquid is sucked in through the liquid absorption holes densely distributed in the middle and upper part of the side wall for sufficient mixing. Moreover, since the liquid absorption holes are tapered holes, The end with a small diameter is connected to the liquid absorption mixing chamber, so that when the absorption liquid enters the liquid absorption mixing chamber through the absorption hole, the absorption liquid chases the gradually shrinking wall of the absorption hole, and the flow rate gradually increases. When entering the liquid absorption mixing chamber, due to the sudden increase in space, it will be broken and atomized, thereby fully mixing with the fuel gas, thereby increasing the mixed contact effect of the fuel gas and the liquid, and facilitating the full contact and reaction between the sulfur-containing components in the fuel gas and the absorption liquid; compared with the existing nozzle spraying atomized absorption liquid to react with the fuel gas, it has better contact effect and better desulfurization efficiency; compared with the existing method of directly passing the fuel gas into the absorption liquid, it saves the amount of absorption liquid and improves the use efficiency of the absorption liquid;

[0034] 3) In order to further enhance the effect of breaking up and atomizing the absorption liquid, the present invention horizontally arranges a flow-breaking plate in the absorption mixing chamber. When the high-speed mixed gas-liquid mixture impacts the flow-breaking plate, the absorption liquid will be further broken up and atomized, and will be diverted and diffused to both sides, thereby further enhancing the mixing effect with the fuel gas. In addition, the surface of the flow-breaking plate can be provided with through-holes, which are also conical holes with a large top and a small bottom. When the gas-liquid mixture passes through these through-holes, it is similar to passing through a Venturi structure, and the liquid phase will be further atomized into smaller droplets to contact and react with the fuel gas. In addition, the flow-breaking plate can be fixedly connected, preferably by a tension spring, so that under the high-speed impact of the gas-liquid mixture, the flow-breaking plate itself can vibrate at a high frequency, thereby further breaking up the droplets impacting it and diverting them to different positions, so that they can better mix and contact with the fuel gas.

[0035] 4) In order to further improve the removal of sulfur from the fuel gas, especially the removal of organic sulfur, the desulfurized fuel gas is introduced into the absorption liquid in the secondary desulfurization zone in the form of microbubbles with a diameter of less than 1 mm. With the help of an ultrasonic generator, the high energy of ultrasonic cavitation is coupled with the microbubbles of the fuel gas. Under the combined physical and chemical effects, the desulfurization effect of the absorption liquid is enhanced, effectively removing the organic sulfur in the fuel gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1This is a schematic diagram of the overall system framework of the present invention;

[0037] Figure 2 This is a schematic diagram of the structure of the flue gas waste heat recovery device (two plate heat exchanger units connected in series);

[0038] Figure 3 It is a structural schematic diagram of the plate heat exchanger unit;

[0039] Figure 4 This is a schematic structural diagram of an implementation scheme of a desulfurization device;

[0040] Figure 5 for Figure 4 Schematic diagram of the structure of the middle-level desulfurization unit;

[0041] Figure 6 for Figure 5 A schematic diagram of the central liquid storage pipe and the surrounding gas-liquid mixing area;

[0042] Figure 7 for Figure 6 A magnified schematic diagram of point A in the middle;

[0043] Figure 8 for Figure 5 Schematic diagram of the gas-liquid mixing zone and the peripheral liquid storage zone;

[0044] Figure 9 Schematic diagram of another embodiment of a desulfurization device;

[0045] Figure 10 for Figure 9 Schematic diagram of the structure of the middle-level desulfurization unit;

[0046] Figure 11 for Figure 9 A schematic diagram of the central liquid storage pipe and the surrounding gas-liquid mixing area;

[0047] Figure 12 for Figure 11 A magnified schematic diagram of point B in the middle;

[0048] Figure 13 for Figure 12 The enlarged schematic diagram of point C in the middle (schematic diagram of the structure of the flow-breaking plate);

[0049] Figure 14 for Figure 10 Schematic diagram of the gas-liquid mixing zone and the peripheral liquid storage zone;

[0050] Reference numerals: 1, plate heat exchanger unit, 101, shell, 102, fuel gas flow channel, 103, fuel gas discharge manifold, 104, fuel gas inlet manifold, 105, flue gas flow channel, 106, flue gas inlet pipe, 107, flue gas discharge pipe, 2, primary desulfurization zone, 201, primary absorption liquid injection pipe, 202, primary absorption liquid discharge pipe, 3, secondary desulfurization zone, 301, secondary absorption liquid discharge pipe, 302, secondary absorption liquid injection pipe, 303, Purified gas discharge pipe, 4. Central liquid storage pipe, 5. Gas-liquid mixing area, 501. Annular partition, 502. Overflow absorption chamber, 503. Liquid absorption mixing chamber, 504. Breaker plate, 6. Peripheral liquid storage area, 601. Liquid absorption area, 602. Liquid absorption hole, 603. Solid part, 7. Absorption liquid buffer area, 8. Absorption liquid convergence area, 9. Fuel gas pipeline, 901. Annular gas distribution pipe, 10. Microbubble generator, 11. Fuel gas convergence coil, 12. Ultrasonic generator. DETAILED DESCRIPTION

[0051] The technical solution of the present invention is further elaborated in detail below in conjunction with specific embodiments. The parts not elaborated in the following embodiments of the present invention, such as: the specific structures of the combustion furnace, the gas-water separator, and the carbon dioxide capture device, the source and oxygen content of the oxygen-enriched air, the ratio of oxygen-enriched air to the fuel gas, the compression and storage of the carbon dioxide recovered by the carbon dioxide capture device, the composition of the absorption liquid in the desulfurization device, the recovery and treatment of the absorption liquid, whether a catalyst needs to be added and the type of catalyst added, the pressure and time conditions of the reaction, the flow rate and flow of the fuel gas, and the adaptive adjustment of the equipment when used for catalytic oxidation desulfurization or alcohol-ammonia desulfurization, etc., should be understood as existing technologies that are known or should be known to those skilled in the art.

[0052] Example 1

[0053] A method for recovering water and carbon dioxide from a net-zero fuel furnace, such as Figure 1 As shown, the following steps are included:

[0054] 1) Desulfurize the fuel gas to form net-zero fuel gas with a sulfur content of no more than 1 ppm. Then, the net-zero fuel gas and oxygen-enriched air are fed into the combustion furnace for full combustion. The ratio of net-zero fuel gas to oxygen-enriched air is adjusted according to actual needs.

[0055] 2) The flue gas generated by the combustion furnace is processed through waste heat recovery to form low-temperature flue gas. The temperature of the low-temperature flue gas is 50-60°C, which is convenient for the operation in the subsequent steps. In this process, the waste heat of the flue gas is used to preheat the net-zero fuel gas. In other words, the flue gas and the net-zero fuel gas are heat-exchanged in the heat exchange equipment to increase the temperature of the net-zero fuel gas. At the same time, the temperature of the flue gas is gradually reduced to 50-60°C.

[0056] 3) The low-temperature flue gas in step 2) is subjected to gas-water separation treatment, generally using a gas-water separator to separate condensed water and dehumidified flue gas, with the condensed water being reserved;

[0057] 4) The dehumidified flue gas from step 3) is fed into a carbon dioxide capture device, and the recovered carbon dioxide is compressed, stored, and utilized. The recovered water is treated together with the condensed water from step 3) to form pure water. The water can be treated using an existing stripping device or other means to remove impurities from the water.

[0058] Example 2

[0059] A net zero fuel burner water and carbon dioxide recovery system, such as Figure 1 As shown, it includes a desulfurization device, a flue gas waste heat recovery device, a gas-water separator and a carbon dioxide capture device, wherein the fuel gas first enters the desulfurization device for desulfurization treatment to form a net zero fuel gas with a sulfur content of no more than 1ppm, which is then sent to the combustion furnace together with oxygen-enriched air for combustion. The generated high-temperature flue gas is passed into the flue gas waste heat recovery device and undergoes heat exchange with the net zero fuel gas. After the temperature is reduced to 50-60°C to form low-temperature flue gas, it is sent to the gas-water separator to separate condensed water and dehumidified flue gas. The dehumidified flue gas is then passed into the carbon dioxide capture device, and the separated carbon dioxide is compressed and stored. The separated water is treated together with the condensed water generated in the gas-water separator ( Figure 1 The flue gas waste heat recovery device includes multiple sets of plate heat exchanger units 1 connected in series. The number of plate heat exchanger units 1 connected in series is designed according to the actual working conditions so that the final flue gas temperature is reduced to 50-60°C. Figure 2As shown, two sets of plate heat exchanger units 1 are connected in series. Each set of plate heat exchanger units 1 includes a closed shell 101 with a hollow interior. The shell 101 is generally a flat rectangular structure. Several closed hollow plate-like members are arranged in parallel in the shell 101. The hollow plate-like members are generally flat rectangular shapes. Their length is shorter than the length of the shell 101, so that gap channels are formed between their two ends and the ends of the shell 101. The width of the hollow plate-like members is consistent with the width of the interior of the shell 101, so that the two sides of the width direction are fixed to the two side walls of the width direction of the interior of the shell 101; the hollow plate-like members are made of metal. The thin-walled structure is made of metal material and is fixed in the shell 101 by a number of connecting rods. The preferred hollow plate-like members are tilted in the shell 101, and at this time, the shell 101 is also tilted. A fuel gas flow channel 102 is formed inside each hollow plate-like member. The two ends of all hollow plate-like members are respectively connected to the fuel gas discharge collection pipe 103 and the fuel gas inlet collection pipe 104. The fuel gas discharge collection pipe 103 and the fuel gas inlet collection pipe 104 pass through the two ends of each hollow plate-like member respectively, and are connected to the inside of each hollow plate-like member through the channel. The end extends out of the shell 101, and the two ends of each hollow plate-like member are connected to the fuel gas discharge collection pipe 103 and the fuel gas inlet collection pipe 104. A flue gas flow channel 105 is formed on the side, and all the flue gas flow channels 105 are connected to the flue gas inlet pipe 106 and the flue gas exhaust pipe 107 at both ends of the shell 101. The flue gas inlet pipe 106 and the fuel gas exhaust collection pipe 103 are distributed at one end of the shell 101 in the length direction, and the flue gas exhaust pipe 107 and the fuel gas entry collection pipe 104 are distributed at the other end of the shell 101 in the length direction. Along the direction of flue gas flow, these plate heat exchanger units 1 are connected in series, the flue gas inlet pipe 106 of the first plate heat exchanger unit 1 is connected to the flue gas exhaust port of the combustion furnace, and the flue gas exhaust pipe 106 of the last plate heat exchanger unit 1 is connected to the flue gas exhaust port of the combustion furnace. 07 is connected to the gas-water separator, the flue gas exhaust pipe 107 of the upper group of plate heat exchanger units 1 is connected to the flue gas inlet pipe 106 of the next group of plate heat exchanger units 1, along the fuel gas flow direction, the fuel gas flow direction is opposite to the flue gas flow direction, the fuel gas exhaust collection pipe 103 of the upper group of plate heat exchanger units 1 is connected to the fuel gas inlet collection pipe 104 of the next group of plate heat exchanger units 1, the fuel gas exhaust collection pipe 103 of the first plate heat exchanger unit 1 is connected to the fuel gas inlet of the combustion furnace, and the fuel gas inlet collection pipe 104 of the last plate heat exchanger unit 1 is connected to the gas-water separator.

[0060] In this embodiment, the carbon dioxide capture device is a solid amine adsorption carbon dioxide capture device. For the specific structure and principle of the solid amine adsorption carbon dioxide capture device, please refer to the adsorption tower in the flue gas carbon dioxide recovery process disclosed in application number 202110719538.8.

[0061] Example 3

[0062] This embodiment is an improvement on the basis of embodiment 2. Its main structure is the same as that of embodiment 2. The improvement is that the desulfurization device can adopt the existing wet desulfurization device, but the device with the following structure is preferred: Figure 3 and 5 As shown, the desulfurization device includes a hollow and closed primary desulfurization zone 2. The primary desulfurization zone 2 is a closed metal shell, which is generally in the shape of a rectangular parallelepiped, a cylinder, or a polygonal prism. A central liquid storage pipe 4 is provided in the central area of ​​the shell. Figure 5 and 10 As shown, the central liquid storage pipe 4 is in the shape of a hollow cylinder, and its material is generally ceramic, or a metal material covered with a ceramic coating. Of course, other corrosion-resistant materials that do not react with the absorption liquid can also be used. Annular gas-liquid mixing areas 5 and peripheral liquid storage areas 6 are alternately arranged around the central liquid storage pipe 4, and the outermost layer is the gas-liquid mixing area 5. The tops of the central liquid storage pipe 4 and the peripheral liquid storage area 6 are closed, and an annular gas distribution pipe 901 is provided inside the closed end. The cross-section of the annular gas distribution pipe 901 generally fits the inner wall of the central liquid storage pipe 4. The bottoms of the central liquid storage pipe 4 and the peripheral liquid storage area 6 have absorbent injection channels, so that the absorbent enters the gas-liquid mixing area 5 and the peripheral liquid storage area 6 synchronously from bottom to top. The absorbent is a liquid that has the function of eliminating inorganic sulfur and organic sulfur; as shown Figure 6 、 Figure 8 、 Figure 11 and Figure 14 As shown, the gas-liquid mixing zone 5 is provided with an annular partition 501 parallel to its side wall, and the annular partition 501 divides its internal space into a liquid suction mixing chamber 503 close to the central liquid storage pipe 4 and an overflow absorption chamber 502 away from the central liquid storage pipe 4. The material of the annular partition 501 is also selected from ceramics. Of course, other corrosion-resistant materials that do not react with the absorption liquid can also be selected. Among them, the top of the liquid suction mixing chamber 503 is connected to the annular gas distribution pipe 901, and the middle and upper part of the side wall of the liquid suction mixing chamber 503 is provided with a central storage pipe. The liquid absorption area 601 connected to the liquid pipe 4 or the peripheral liquid storage area 6 is composed of densely distributed liquid absorption holes 602. The height of the liquid absorption area 601 is 30-70% of the height of the liquid absorption mixing chamber 503. The fuel gas in the annular gas distribution pipe 901 enters the liquid absorption mixing chamber 503 at a high speed and generates negative pressure. The fuel gas is sucked into the absorbent through the liquid absorption holes 602 and fully mixed and reacted with the fuel gas. The absorbent enters the overflow absorption chamber 502 along the channel connected to the overflow absorption chamber 502 at the bottom, and gas-liquid separation is achieved at the top of the overflow absorption chamber 502.

[0063] An absorption liquid buffer zone 7 and an absorption liquid gathering zone 8 are respectively provided at the bottom and top of the primary desulfurization zone 2. The absorption liquid buffer zone 7 and the absorption liquid gathering zone 8 are also independent closed spaces. The annular gas distribution pipe 901 is connected with the fuel gas pipeline 9. The fuel gas pipeline 9 is provided in the absorption liquid gathering zone 7 and extends to the outside of the primary desulfurization zone 1 to be connected with the fuel gas source. After being pressurized, the fuel gas enters the fuel gas pipeline 9 at a high speed and then enters the annular gas distribution pipe 901 respectively. The absorbent injection holes at the bottom of the central liquid storage pipe 4 and the peripheral liquid storage zone 6 are both connected with the absorption liquid buffer zone 7, so that the absorption liquid enters the gas-liquid mixing zone 5 and the peripheral liquid storage zone 6 synchronously from bottom to top. A primary absorption liquid injection pipe 201 is provided on one side of the absorption liquid buffer zone 7; the top of the overflow absorption chamber 502 is connected with the absorption liquid gathering zone 8, and a primary absorption liquid discharge pipe 202 is provided on one side of the absorption liquid gathering zone 8, and the top is connected with the fuel gas gathering coil 11, thereby realizing gas-liquid separation.

[0064] In this embodiment, the fuel gas enters the liquid absorption mixing chamber 503 at a high speed and generates a negative pressure. The purpose is to generate a negative pressure to absorb the absorption liquid. How high the flow rate is and how much negative pressure is generated to absorb the absorption liquid is affected by factors other than the size of the equipment and the size of the liquid absorption hole. It is also affected by parameters such as the composition and density of the absorption liquid. Therefore, no limitation is made in this embodiment. In actual application, technical personnel in this field need to conduct experiments based on the specific conditions of the equipment to obtain the most preferred operating parameters.

[0065] In this embodiment, the liquid suction hole 602 is preferably a tapered hole, such as Figure 7 、 Figure 12 and Figure 13 As shown, the end with a smaller diameter is connected to the liquid suction mixing chamber 503. Generally, the diameter of the small end of the liquid suction hole 602: the diameter of the large end: the hole depth = 1:3-5:2-5. Of course, other ratios can also be used.

[0066] Example 4

[0067] This embodiment is an improvement on the basis of embodiment 3. Its main structure is the same as that of embodiment 3. The improvement is as follows: Figure 4 and Figure 9 As shown, the fuel gas converging coil 11 is connected to the secondary desulfurization zone 3 provided above the primary desulfurization zone 2, so that the fuel gas undergoes secondary desulfurization in the secondary desulfurization zone 3. The middle, bottom and top of the secondary desulfurization zone 3 are respectively provided with a secondary absorption liquid injection pipe 302, a secondary absorption liquid discharge pipe 301 and a purified gas discharge pipe 303, and the secondary absorption liquid injection pipe 302 sprays the desulfurization absorption liquid downward from the middle of the secondary desulfurization zone 3 through a number of atomizing nozzles. The sprayed desulfurization absorption liquid is in mist form and contacts and reacts with the rising fuel gas during the descending process.

[0068] In this embodiment, the portion of the secondary absorption liquid injection pipe 302 in the secondary desulfurization zone 3 is spirally shaped extending from the edge to the center, and a number of atomizing nozzles are distributed along its extension direction. The projections of these atomizing nozzles in the horizontal plane are evenly distributed, and the atomizing nozzles spray atomized absorption liquid downward to form an absorption liquid accumulation area at the bottom of the secondary desulfurization zone 3. The fuel gas convergence coil 11 first passes the fuel gas into the absorption liquid accumulation area, so that it first reacts with the absorption liquid in the accumulation area, and then reacts again with the atomized absorption liquid sprayed from the atomizing nozzle during the upward escape process, and finally is discharged from the purified gas discharge pipe 303 at the top. At this time, a secondary absorption liquid discharge pipe 301 is set at the bottom of the secondary desulfurization zone 3 to maintain the absorption liquid height in the absorption liquid accumulation area at about 1 / 3 of the internal height of the secondary desulfurization zone 3.

[0069] In this embodiment, the primary desulfurization zone 2 and the secondary desulfurization zone 3 can be designed as separate structures or as an integrated structure.

[0070] Example 5

[0071] This embodiment is an improvement on the basis of Example 4. Its main structure is the same as that of Example 4. The improvement is that the fuel gas convergence coil 11 is located at the bottom of the secondary desulfurization zone 3, and the fuel gas is delivered into the secondary desulfurization zone 3 in the form of microbubbles with a diameter not exceeding 1 mm through a number of microbubble generators 10 located at the bottom of the secondary desulfurization zone 3. After reacting with the absorption liquid in the secondary desulfurization zone 3, the fuel gas is discharged through the purified gas exhaust pipe 303 at the top.

[0072] The microbubble generator 10 in this embodiment can be an existing microbubble generator. The amount of microbubbles introduced needs to be adjusted by those skilled in the art based on the specific application, the type of absorption liquid, the type of catalyst, the temperature and parameters of the reaction, etc., so as to obtain the optimized parameters.

[0073] In this embodiment, an external pressurizing device may be used to pressurize the fuel gas in the fuel gas converging coil 11 , thereby facilitating the generation of microbubbles with smaller diameters.

[0074] In addition, in this embodiment, a number of ultrasonic generators 12 are provided on the inner wall of the secondary desulfurization zone 3. These ultrasonic generators 12 are existing equipment and are completely immersed in the liquid absorbent. They are distributed at different heights. In addition, the number of ultrasonic generators 12 at the same height is determined by the overall size of the reactor. If the size is larger, two to four generators can be arranged around the same height. The power of the ultrasonic generator 12 also needs to be adjusted by technical personnel in this field according to the specific application scenarios and the type of absorption liquid, the type of catalyst, the temperature and parameters of the reaction, etc., so as to obtain the optimized parameters.

[0075] Example 6

[0076] This embodiment is another improved solution based on the embodiment 3. Its main structure is the same as that of the embodiment 3. The improvement is as follows: Figure 11 and Figure 12 As shown, the liquid absorption area 601 is a multi-segment hole distribution area spaced apart along the height direction, and a solid part 603 without holes is formed between adjacent hole distribution areas, and the height of the solid part 603 does not exceed 1 / 5 of the height of the hole distribution area.

[0077] Example 7

[0078] This embodiment is another improved solution based on the embodiment 3. Its main structure is the same as that of the embodiment 3. The improvement is as follows: Figure 10 、 Figure 11 、 Figure 12 and Figure 13 As shown, at least one flow-breaking plate 504 is horizontally arranged in the liquid suction and mixing chamber 503. The flow-breaking plate 504 is annular and is located in the middle position in the width direction of the liquid suction and mixing chamber 503. Its width accounts for 60-80% of the width of the liquid suction and mixing chamber 503, and a fluid channel is formed between the edge of the flow-breaking plate 504 and the inner wall of the liquid suction and mixing chamber 503.

[0079] In this embodiment, the flow breaking plate 504 can be a solid plate or a Figure 13 As shown, the surface of the flow-breaking plate 504 is densely covered with through holes, and the direction of the through holes is consistent with the flow direction of the gas-liquid mixture;

[0080] In this embodiment, the through hole can be a straight hole with a constant diameter, such as Figure 13 As shown, it can also be a variable diameter hole. Preferably, the diameter of the through hole gradually decreases from top to bottom, and the bottom diameter of the through hole: the top diameter: the hole depth = 1:4-10:3-6.

[0081] In this embodiment, the flow breaking plate 504 can be fixedly connected to the inner wall of the liquid suction mixing chamber 503. Of course, it is preferred that Figure 13 As shown, the two sides of the flow-breaking plate 504 are fixed to the two side walls of the liquid suction mixing chamber 503 by a plurality of tension springs, so that the flow-breaking plate 504 vibrates at high frequency under the impact of the high-speed gas-liquid mixture, and the installation position of the tension spring is on the solid part 603.

Claims

1. A net zero fuel combustion furnace water and carbon dioxide recovery system, comprising a desulfurization device, a flue gas waste heat recovery device, a gas-water separator and a carbon dioxide capture device, wherein: The fuel gas first enters the desulfurization device for desulfurization treatment to form net zero fuel gas which is then sent to the combustion furnace for combustion. The high-temperature flue gas generated is passed into the flue gas waste heat recovery device and undergoes heat exchange with the net zero fuel gas to form low-temperature flue gas which is then sent to the gas-water separator to separate condensed water and dehumidified flue gas. The dehumidified flue gas is then passed into the carbon dioxide capture device. The separated carbon dioxide is compressed and stored. The separated water is processed together with the condensed water generated in the gas-water separator to form pure water. The feature is that the flue gas waste heat recovery device includes a plurality of plate heat exchanger units (1) connected in series, each plate heat exchanger unit (1) includes an internally hollow closed shell (101), and a plurality of closed hollow plate-like members are arranged in parallel in the shell (101). The interior of each hollow plate-like member is A fuel gas flow channel (102) is formed, and both ends of all hollow plate-like members are respectively connected to the fuel gas exhaust collection pipe (103) and the fuel gas inlet collection pipe (104). Both sides of each hollow plate-like member form a flue gas flow channel (105). All flue gas flow channels (105) are connected to the flue gas inlet pipe (106) and the flue gas exhaust pipe (107) at both ends of the shell (101). The flue gas exhaust pipe (107) of the upper group of plate heat exchanger units (1) is connected to the flue gas inlet pipe (106) of the lower group of plate heat exchanger units (1). Along the fuel gas flow direction, the fuel gas exhaust collection pipe (103) of the upper group of plate heat exchanger units (1) is connected to the fuel gas inlet collection pipe (104) of the lower group of plate heat exchanger units (1); The desulfurization device comprises a primary desulfurization zone (2) which is hollow and closed inside, a central liquid storage pipe (4) being provided in the central area of ​​the primary desulfurization zone (2), an annular gas-liquid mixing zone (5) and a peripheral liquid storage zone (6) being alternately provided around the central liquid storage pipe (4), the tops of the central liquid storage pipe (4) and the peripheral liquid storage zone (6) being closed and provided with an annular gas distribution pipe (901), and the bottoms of the central liquid storage pipe (4) and the peripheral liquid storage zone (6) being provided with an absorbent injection channel; an annular partition (501) parallel to the side wall of the gas-liquid mixing zone (5) being provided, and the annular partition (501) dividing the internal space of the gas-liquid mixing zone (5) into a liquid absorption mixing chamber (503) close to the central liquid storage pipe (4) and a liquid absorption mixing chamber (503) away from the central liquid storage pipe (4). The overflow absorption chamber (502) of the pipe (4) is connected to the annular gas distribution pipe (901) at the top of the liquid absorption mixing chamber (503). A liquid absorption area (601) connected to the central liquid storage pipe (4) or the peripheral liquid storage area (6) is provided in the middle and upper part of the liquid absorption mixing chamber (503). The liquid absorption area (601) is composed of densely distributed liquid absorption holes (602). The fuel gas in the annular gas distribution pipe (901) enters the liquid absorption mixing chamber (503) at a high speed and generates negative pressure. The absorbent is absorbed through the liquid absorption holes (602) and fully mixed with the fuel gas for reaction. The absorbent enters the overflow absorption chamber (502) along the channel connected to the overflow absorption chamber (502) at the bottom, and gas-liquid separation is achieved at the top of the overflow absorption chamber (502). An absorption liquid buffer zone (7) and an absorption liquid convergence zone (8) are respectively provided at the bottom and top of the primary desulfurization zone (2); the annular gas distribution pipe (901) is connected to the fuel gas pipeline (9); the absorbent injection holes at the bottom of the central liquid storage pipe (4) and the peripheral liquid storage zone (6) are both connected to the absorption liquid buffer zone (7); the top of the overflow absorption chamber (502) is connected to the absorption liquid convergence zone (8); a primary absorption liquid discharge pipe (202) is provided on one side of the absorption liquid convergence zone (8), and the top is connected to the fuel gas convergence coil (11), thereby achieving gas-liquid separation.

2. The net zero fuel furnace water and carbon dioxide recovery system according to claim 1, characterized in that: The carbon dioxide capture device is a solid amine adsorption carbon dioxide capture device.

3. The net zero fuel furnace water and carbon dioxide recovery system according to claim 1, characterized in that: The fuel gas converging coil (11) is connected to the secondary desulfurization zone (3) provided above the primary desulfurization zone (2), so that the fuel gas undergoes secondary desulfurization in the secondary desulfurization zone (3). A secondary absorption liquid injection pipe (302), a secondary absorption liquid discharge pipe (301) and a purified gas discharge pipe (303) are respectively provided at the middle, bottom and top of the secondary desulfurization zone (3). The secondary absorption liquid injection pipe (302) sprays the desulfurization absorption liquid downward from the middle of the secondary desulfurization zone (3) through a plurality of atomizing nozzles.

4. The net zero fuel furnace water and carbon dioxide recovery system according to claim 3, characterized in that: The fuel gas converging coil (11) is located at the bottom of the secondary desulfurization zone (3), and the fuel gas is sent into the secondary desulfurization zone (3) in the form of microbubbles with a diameter not exceeding 1 mm through a plurality of microbubble generators (10) located at the bottom of the secondary desulfurization zone (3). After reacting with the absorption liquid in the secondary desulfurization zone (3), the fuel gas is discharged through the purified gas discharge pipe (303) at the top.

5. The net zero fuel furnace water and carbon dioxide recovery system according to claim 3, characterized in that: Several ultrasonic generators (12) are provided in the secondary desulfurization zone (3).

6. The net zero fuel furnace water and carbon dioxide recovery system according to claim 1, characterized in that: The liquid suction hole (602) is a tapered hole, and the end with a smaller diameter is connected to the liquid suction mixing chamber (503).

7. The net zero fuel furnace water and carbon dioxide recovery system according to claim 1, characterized in that: The liquid absorption area (601) is a plurality of sections of hole-distributed areas spaced apart in the height direction, with a solid portion (603) formed between adjacent hole-distributed areas.

8. The net zero fuel furnace water and carbon dioxide recovery system according to claim 1, characterized in that: At least one flow-breaking plate (504) is horizontally arranged in the liquid suction and mixing chamber (503), and a fluid channel is formed between the edge of the flow-breaking plate (504) and the inner wall of the liquid suction and mixing chamber (503).

9. The net zero fuel furnace water and carbon dioxide recovery system according to claim 8, characterized in that: The surface of the flow-breaking plate (504) is densely covered with through holes.

10. The net zero fuel furnace water and carbon dioxide recovery system according to claim 8, characterized in that: The two sides of the flow-breaking plate (504) are fixed to the two side walls of the liquid suction mixing chamber (503) via a plurality of tension springs, so that the flow-breaking plate (504) vibrates at a high frequency under the impact of the high-speed gas-liquid mixture.

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