System for purifying flue gas by using seawater

Abstract

The utility model belongs to the technical field of waste gas treatment, and particularly relates to a system for purifying flue gas by utilizing seawater. The system comprises a first static mixer, a second static mixer and a third static mixer, wherein the first static mixer comprises a flue gas inlet for flue gas and chlorine gas to enter and a flue gas outlet for outputting mixed flue gas containing chlorine gas; a first UV photolysis area, a first electrolysis oxygen production area, a first alkaline seawater spraying area, a chlorine filling area, a second UV photolysis area, a second electrolysis oxygen production area and a second alkaline seawater spraying area are sequentially arranged in the UV photolysis absorption tower according to the sequence of gas treatment, and the first UV photolysis area is located in an alkaline solution; the smoke outlet is communicated with the first UV photolysis area; and the seawater concentration and electrolysis module is communicated with the first alkaline seawater spraying area and the second alkaline seawater spraying area and is used for concentrating and electrolyzing seawater into high-concentration alkaline seawater and conveying the high-concentration alkaline seawater to the first alkaline seawater spraying area and the second alkaline seawater spraying area. The system disclosed by the utility model can be used for effectively treating pollutants in the flue gas.

Description

Technical Field

[0001] This utility model belongs to the field of waste gas treatment technology, specifically relating to a system for purifying flue gas using seawater. Background Technology

[0002] In the field of energy utilization, there is a sharp contradiction between pollutants generated by fuel combustion and the ecological environment. Combustion products not only fail to achieve a positive interaction with the natural environment, but also cause great damage to the ecosystem, and direct emissions will have serious consequences. Taking the combustion of ship fuel as an example, combustion mainly produces pollutants such as sulfur oxides (SOx, mainly SO2), nitrogen oxides (NOx), and carbon oxides (mainly CO2), as well as escaped and leaked gaseous fuels. These pollutants contribute to a series of environmental problems such as acid rain, the greenhouse effect, and air pollution, and are also harmful to human health, causing damage to the respiratory system, cardiovascular system, and other bodily functions. Utility Model Content

[0003] In view of the above problems, this utility model provides a system for purifying flue gas using seawater, which includes a first static mixer, a UV photolysis absorption tower, and a seawater concentration electrolysis module. It can efficiently purify and treat pollutants such as sulfur oxides, nitrogen oxides, and carbon oxides in flue gas, as well as small amounts of gases such as methane, methanol, and ammonia. It is especially suitable for treating flue gas from dual-fuel engines of ships.

[0004] To achieve the above objectives, this utility model provides a system for purifying flue gas using seawater, comprising:

[0005] The first static mixer includes an inlet for supplying flue gas and chlorine gas and an outlet for discharging the mixed flue gas containing chlorine gas.

[0006] The UV photolysis absorption tower has the following internal components arranged in sequence according to the gas processing order: a first UV photolysis zone, a first electrolysis oxygen generation zone, a first alkaline seawater spray zone, a chlorine injection zone, a second UV photolysis zone, a second electrolysis oxygen generation zone, and a second alkaline seawater spray zone. The first UV photolysis zone is located in an alkaline solution. The flue gas outlet is connected to the first UV photolysis zone.

[0007] The seawater concentration and electrolysis module is connected to the first alkaline seawater spray zone and the second alkaline seawater spray zone, and is used to concentrate and electrolyze seawater into highly concentrated alkaline seawater and then transport it to the first alkaline seawater spray zone and the second alkaline seawater spray zone.

[0008] Furthermore, the air inlet end of the first UV photolysis zone is provided with an air inlet area, which includes a flue gas pipe extending from the outside of the tower body into the bottom of the tower body. The end of the flue gas pipe is connected to a bubbling pipe, and the end of the bubbling pipe is connected to a swirl tube.

[0009] Furthermore, both the first alkaline seawater spray zone and the second alkaline seawater spray zone include a connected inlet pipe and a spray head.

[0010] Furthermore, a gas-lifting tower plate is provided between the first UV photolysis zone and the first electrolytic oxygen-generating zone, and between the second UV photolysis zone and the second electrolytic oxygen-generating zone. The gas-lifting tower plate is provided with a drain port, and a downward drain pipe is connected to the drain port.

[0011] Furthermore, a gas lifting tower plate is provided between the chlorine gas injection zone and the second UV photolysis zone, and the chlorine gas injection zone includes a connected injection main pipe and multiple injection branch pipes.

[0012] Furthermore, a wire mesh demister is installed above the second alkaline seawater spray zone.

[0013] Furthermore, both the first UV photolysis zone and the second UV photolysis zone include multiple UV lamps, which are distributed radially at intervals along the tower body and are vertically aligned along the axial direction of the tower body.

[0014] Furthermore, the bottom of the tower body is connected to a liquid outlet pipe, and a packing negative electrode electrolysis tube is built into the liquid outlet pipe. The packing negative electrode electrolysis tube is connected to the positive electrode of an external power supply; the catalytic electrolysis packing is connected to the negative electrode of an external power supply.

[0015] Furthermore, one or more intermediate electrolysis oxygen generation zones or one or more intermediate UV photolysis zones are provided between the first alkaline seawater spraying zone and the chlorine injection zone, and at least one intermediate electrolysis oxygen generation zone is provided below each of the intermediate UV photolysis zones.

[0016] Furthermore, if one or more intermediate electrolytic oxygen-producing zones are provided between the first alkaline seawater spraying zone and the chlorine injection zone, and a gas-lifting tower plate is provided between the intermediate electrolytic oxygen-producing zones, and an intermediate alkaline seawater spraying zone is provided between each stage of the gas-lifting tower plate and the intermediate electrolytic oxygen-producing zone located below that stage of the gas-lifting tower plate.

[0017] Furthermore, if one or more intermediate UV photolysis zones are provided between the first alkaline seawater spraying zone and the chlorine injection zone, and at least one intermediate electrolysis oxygen generation zone is provided below each intermediate UV photolysis zone, a gas lifting tower plate can be provided between each intermediate UV photolysis zone and the intermediate electrolysis oxygen generation zone located below that intermediate UV photolysis zone, and an intermediate alkaline seawater spraying zone is provided between each gas lifting tower plate and the intermediate electrolysis oxygen generation zone located below that gas lifting tower plate.

[0018] Furthermore, the UV photolysis absorption tower includes a tower body, the top of which is provided with an outlet, and the outlet and the inlet are respectively connected to a flue gas composition analyzer.

[0019] Furthermore, the bottom of the tower body is provided with a liquid outlet, and a second static mixer is connected to the liquid outlet.

[0020] Furthermore, both the first electrolytic oxygen-generating zone and the second electrolytic oxygen-generating zone contain catalytic electrolysis filler, which includes titanium metal filler and a catalytic electrolysis layer sprayed on the titanium metal filler.

[0021] Furthermore, the structure of the titanium metal packing is selected from 250Y, Raschig rings, Pall rings, etc.

[0022] This invention utilizes a method for purifying flue gas using seawater, combining UV photocatalytic oxidation decomposition, catalytic electrolysis for oxygen production, and alkaline solution absorption of acidic gases. First, flue gas and chlorine are passed into an alkaline solution, where initial absorption occurs. Then, active oxygen and ClO₂ are absorbed. - The existing alkaline solution undergoes photocatalytic oxidation and decomposition in the first UV photolysis zone, while the remaining gas enters the first electrolysis oxygen-generating zone. The active oxygen produced in the first electrolysis oxygen-generating zone is mixed with ClO₂. - The gas mixes with flue gas and enters the second UV photolysis zone for photocatalytic oxidation and decomposition, oxidizing CH4 and NOx in the flue gas into CO2 and HNO3, or oxidizing NH3 into N2. Some active oxygen dissolves in the first alkaline seawater and flows back into the alkaline solution to catalytically oxidize pollutants in the first UV photolysis zone. Under the action of the second alkaline seawater, acidic gases and Cl2 in the flue gas are absorbed in the second electrolytic oxygen-producing zone. This method of flue gas purification using seawater is applicable to the purification of various pollutants, has high pollutant absorption efficiency, and is very environmentally friendly. Attached Figure Description

[0023] Figure 1 This is a flowchart illustrating the method for purifying flue gas using seawater in the embodiment.

[0024] Figure 2 This is a system structure diagram of using seawater for flue gas purification in the embodiment;

[0025] Figure 3 This is a schematic diagram of the UV photolysis absorption tower in the embodiment.

[0026] The components are as follows: 1. First static mixer; 2. UV photolysis absorption tower; 3. Seawater concentration electrolysis module; 4. First UV photolysis zone; 4-1. UV lamp; 5. First electrolysis oxygen production zone; 6. First alkaline seawater spray zone; 7. Chlorine injection zone; 7-1. Injection main pipe; 7-2. Injection branch pipe; 8. Second UV photolysis zone; 9. Second electrolysis oxygen production zone; 10. Second alkaline seawater spray zone; 11. Power supply; 12. Gas riser tray; 13. Drain pipe; 14. Wire mesh demister; 15. Liquid outlet pipe; 16. Packed negative electrode electrolysis tube; 17. Intermediate electrolysis oxygen production zone; 18. Intermediate alkaline seawater spray zone; 19. Gas outlet; 20. Liquid outlet; 21. Second static mixer; 22. Flue gas composition analyzer; 23. Air inlet zone; 24. Flue gas pipeline; 25. Bubble tube; 26. Cyclone tube. Detailed Implementation

[0027] The specific embodiments of this utility model will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this utility model, but are not intended to limit its scope.

[0028] In the description of this utility model, it should be understood that the terms "center," "length," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. In this utility model, unless otherwise expressly specified and limited, "upper" or "lower" of the first feature than the second feature may include direct contact between the first and second features, or it may include contact between the first and second features not being in direct contact but through another feature between them.

[0029] This application provides a system for purifying flue gas using seawater, which can efficiently purify pollutants in flue gas.

[0030] refer to Figure 1 The system for purifying flue gas using seawater according to the embodiments of this application includes: a first static mixer 1, a UV photolysis absorption tower 2, and a seawater concentration electrolysis module 3.

[0031] The first static mixer 1 includes an inlet for supplying flue gas and chlorine gas, and an outlet for discharging the mixed flue gas containing chlorine gas. The interior of the UV photolysis absorption tower 2 is arranged in the order of gas processing, comprising a first UV photolysis zone 4, a first electrolytic oxygen generation zone 5, a first alkaline seawater spray zone 6, a chlorine injection zone 7, a second UV photolysis zone 8, a second electrolytic oxygen generation zone 9, and a second alkaline seawater spray zone 10. The first UV photolysis zone 4 is located in an alkaline solution. Specifically, the first UV photolysis zone 4, the first electrolytic oxygen generation zone 5, the chlorine injection zone 7, the second UV photolysis zone 8, and the second electrolytic oxygen generation zone 9 are each equipped with a connected inlet and outlet. The exhaust port is connected to the air inlet of the first UV photolysis zone 4, the exhaust port of the first UV photolysis zone 4 is connected to the air inlet of the first electrolysis oxygen production zone 5, the exhaust port of the first electrolysis oxygen production zone 5 is connected to the air inlet of the second UV photolysis zone 8, the exhaust port of the second UV photolysis zone 8 is connected to the air inlet of the second electrolysis oxygen production zone 9, and the exhaust port of the chlorine injection zone 7 is connected to the exhaust port of the first electrolysis oxygen production zone 5 and the air inlet of the second UV photolysis zone 8. Seawater sprayed by the first alkaline seawater spray zone 6 acts on the first electrolysis oxygen production zone 5, and seawater sprayed by the second alkaline seawater spray zone 10 acts on the second electrolysis oxygen production zone 9.

[0032] The seawater concentration and electrolysis module 3 is connected to the first alkaline seawater spray zone 6 and the second alkaline seawater spray zone 10. It is used to concentrate and electrolyze seawater into highly concentrated alkaline seawater and then transport it to the first alkaline seawater spray zone 6 and the second alkaline seawater spray zone 10.

[0033] In some embodiments, both the first electrolytic oxygen-generating zone 5 and the second electrolytic oxygen-generating zone 9 contain catalytic electrolysis fillers, which include titanium metal fillers and a catalytic electrolysis layer sprayed onto the titanium metal fillers. The catalytic electrolysis layer comprises a mixture of conventional metal oxides such as nano-iron oxide, nano-nickel oxide, nano-vanadium pentoxide, or platinum oxide particles.

[0034] In some preferred embodiments, the structure of the titanium metal packing is selected from 250Y, Raschig rings, or Pall rings, etc.

[0035] In some embodiments, such as Figure 2 As shown, an inlet zone 23 is provided at the inlet end of the first UV photolysis zone 4. The inlet zone 23 includes a flue gas pipe 24 extending from the outside of the tower body into the bottom of the tower body. A bubbling pipe 25 is connected to the end of the flue gas pipe 24, and a swirl pipe 26 is connected to the end of the bubbling pipe 25. Both the bubbling pipe 25 and the swirl pipe 26 use existing structures. The bubbling pipe 25 and the swirl pipe 26 are provided so that the flue gas entering the liquid at the bottom of the tower forms a flue gas bubbling swirl, which increases the gas-liquid contact probability, prolongs the time of gas in the swirling bubbling stage, and thus prolongs the photolysis oxidation time of the first UV photolysis zone 4. The first alkaline seawater spray zone 6 and the second alkaline seawater spray zone 10 both include a connected liquid inlet pipe and a spray head. The liquid inlet pipe can extend from the outside of the tower body into the tower body.

[0036] In some embodiments, the bottom of the tower is provided with a liquid outlet 20, and a second static mixer 21 is connected to the liquid outlet 20. Excess chlorine gas and alkaline solution are mixed through the second static mixer 21 to form a hypochlorite solution, which can be used for the prevention and control of marine organisms on ships.

[0037] In some embodiments, such as Figure 3 As shown, riser trays 12 are provided between the first UV photolysis zone 4 and the first electrolytic oxygen generation zone 5, and between the second UV photolysis zone 8 and the second electrolytic oxygen generation zone 9. The addition of two stages of riser trays 12 ensures that the gas distribution at the same height within the tower is as uniform as possible, resulting in more complete mass transfer and higher final absorption efficiency of the flue gas. Each riser tray 12 has a drain port connected to a downward drain pipe 13, allowing the liquid on the riser tray 12 to flow smoothly downwards.

[0038] In some embodiments, a gas lifting tower plate 12 is provided between the chlorine injection zone 7 and the second UV photolysis zone 8 to promote secondary mixing of flue gas and chlorine and uniform gas distribution in the tower. The chlorine injection zone 7 includes a connected injection main pipe 7-1 and multiple injection branch pipes 7-2, so that chlorine can enter the tower as evenly as possible and react with the alkaline seawater and flue gas flowing through it.

[0039] In some embodiments, a wire mesh demister 14 is provided above the second alkaline seawater spray zone 10 to remove water from the flue gas.

[0040] In some embodiments, the first UV photolysis zone 4 and the second UV photolysis zone 8 each include a plurality of UV lamps 4-1. The plurality of UV lamps 4-1 are distributed radially at intervals along the tower body and are vertical along the axial direction of the tower body. The UV lamps 4-1 are fixed to the tower wall by lamp holders. The lamp holders are existing known lamp holders, and the connection method between the UV lamps 4-1 and the lamp holders is also a conventional method.

[0041] In some embodiments, the bottom of the tower is connected to an outlet pipe 15, and the outlet pipe 15 contains a packing negative electrode electrolysis tube 16. The packing negative electrode electrolysis tube 16 is connected to the positive electrode of an external power supply 11, and the catalytic electrolysis packing is connected to the negative electrode of the external power supply 11.

[0042] In some embodiments, one or more intermediate electrolysis oxygen-generating zones 17 or one or more intermediate UV photolysis zones are provided between the first alkaline seawater spraying zone 6 and the chlorine injection zone 7, and at least one intermediate electrolysis oxygen-generating zone 17 is provided below each intermediate UV photolysis zone.

[0043] In some preferred embodiments, if one or more intermediate electrolytic oxygen production zones 17 are provided between the first alkaline seawater spray zone 6 and the chlorine injection zone 7, and a gas lifting tower plate 12 is provided between the intermediate electrolytic oxygen production zones 17, and an intermediate alkaline seawater spray zone 18 is provided between each stage of the gas lifting tower plate 12 and the intermediate electrolytic oxygen production zone 17 located below that stage of the gas lifting tower plate 12.

[0044] In some preferred embodiments, if one or more intermediate UV photolysis zones are provided between the first alkaline seawater spray zone 6 and the chlorine injection zone 7, and at least one intermediate electrolysis oxygen generation zone 17 is provided below each intermediate UV photolysis zone, a gas lifting tower plate 12 can be provided between each intermediate UV photolysis zone and the intermediate electrolysis oxygen generation zone 17 located below the intermediate UV photolysis zone, and an intermediate alkaline seawater spray zone 18 is provided between each gas lifting tower plate 12 and the intermediate electrolysis oxygen generation zone 17 located below the gas lifting tower plate 12.

[0045] In some embodiments, the UV photolysis absorption tower 2 includes a tower body, with an outlet 19 at the top for discharging purified gas. The outlet 19 and the inlet are respectively connected to a flue gas composition analyzer 22. The flue gas composition analyzer 22 at the outlet 19 is used to detect the composition of the purified gas, while the flue gas composition analyzer 22 at the inlet is used to detect the initial composition of the flue gas.

[0046] The working method of the system for purifying flue gas using seawater described in this article is as follows:

[0047] (1) Flue gas and chlorine are mixed through the first static mixer 1 and then passed into the alkaline solution S. Part of the flue gas dissolves in the alkaline solution S, and part of the flue gas undergoes the first photocatalytic oxidation decomposition in the first UV photolysis zone 4. The remaining gas enters the first electrolytic oxygen production zone 5.

[0048] (2) In the first electrolysis oxygen production zone 5, the first alkaline seawater undergoes micro-electrolysis to produce active oxygen; at the same time, chlorine is added a second time, which reacts with the first alkaline seawater to produce ClO. - Active oxygen mixed with ClO - Mixed with the flowing flue gas, it enters the second UV photolysis zone 8 to undergo photocatalytic oxidation and decomposition; the active oxygen generated by micro-electrolysis that is not discharged into the flue gas in time dissolves in the first alkaline seawater and flows back into the alkaline solution S to catalyze the oxidation of pollutants in the first UV photolysis zone 4.

[0049] (3) Under the action of the second alkaline seawater, the acidic gases and Cl2 in the flue gas are absorbed in the second electrolysis oxygen production zone 9.

[0050] In some embodiments, the first alkaline seawater and the second alkaline seawater are highly concentrated alkaline seawater with a mass fraction of 10%-15% NaOH. The first alkaline seawater and the second alkaline seawater are sprayed onto the first electrolysis oxygen-producing zone 5 and the second electrolysis oxygen-producing zone 9, respectively. Based on this, the purpose of the seawater concentration electrolysis module 3 is to provide the first alkaline seawater and the second alkaline seawater. The seawater can be concentrated and then electrolyzed using the seawater concentration electrolysis module 3 to obtain highly concentrated alkaline seawater with a mass fraction of 10%-15% NaOH. The seawater concentration electrolysis module 3 can be existing equipment or used in combination with existing equipment. For example, seawater concentration can be achieved using a multi-effect evaporator, a reverse osmosis device, a mechanical vapor recompression (MVR) evaporator, etc., and the electrolysis device can be a conventional electrolytic cell.

[0051] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A system for flue gas cleaning using seawater, characterized in that, The application relates to a static mixing device for treating flue gas, which comprises the following components: a first static mixer (1) comprising a flue gas inlet for flue gas and chlorine gas and a flue gas outlet for outputting mixed flue gas containing chlorine gas; a UV photolysis absorption tower (2), the inside of the UV photolysis absorption tower (2) being sequentially provided with a first UV photolysis zone (4), a first electrolytic oxygen production zone (5), a first alkaline seawater spraying zone (6), a chlorine gas filling zone (7), a second UV photolysis zone (8), a second electrolytic oxygen production zone (9) and a second alkaline seawater spraying zone (10) in sequence according to the processing gas, the first UV photolysis zone (4) being located in an alkaline solution, and the flue gas outlet being communicated with the first UV photolysis zone (4); a seawater concentration electrolysis module (3) being communicated with the first alkaline seawater spraying zone (6) and the second alkaline seawater spraying zone (10) and used for concentrating and electrolyzing seawater into high-concentration alkaline seawater and then conveying the high-concentration alkaline seawater to the first alkaline seawater spraying zone (6) and the second alkaline seawater spraying zone (10).

2. The system for flue gas purification using seawater according to claim 1, wherein The UV photolysis absorption tower (2) comprises a tower body, the top of the tower body is provided with a gas outlet (19), and the gas outlet (19) and the flue gas inlet are respectively connected with a flue gas component analyzer (22).

3. The system for flue gas purification using seawater according to claim 2, characterized by, The bottom of the tower body is provided with a liquid outlet (20), and the liquid outlet (20) is connected with a second static mixer (21).

4. The system for flue gas purification using seawater according to claim 2, wherein The bottom of the tower body is communicated with a liquid outlet pipe (15), the liquid outlet pipe (15) is internally provided with a packed negative electrolysis pipe (16), the packed negative electrolysis pipe (16) is connected with the positive pole of an external power supply (11), and catalytic electrolysis packing is connected with the negative pole of the external power supply (11).

5. The system for flue gas purification using seawater according to claim 2, wherein The gas inlet end of the first UV photolysis zone (4) is provided with a gas inlet zone (23), the gas inlet zone (23) comprises a flue gas pipeline (24) extending into the bottom of the tower body from the outside of the tower body, the end of the flue gas pipeline (24) is connected with a bubbling pipe (25), and the end of the bubbling pipe (25) is connected with a cyclone pipe (26).

6. The system for flue gas purification using seawater according to claim 2, wherein A wire mesh demister (14) is arranged above the second alkaline seawater spraying zone (10) and used for removing water in the flue gas.

7. The system for flue gas purification using seawater according to claim 2, wherein The first UV photolysis zone (4) and the second UV photolysis zone (8) each comprise a plurality of UV lamps (4-1), the plurality of UV lamps (4-1) are distributed in a radial direction of the tower body and arranged in a vertical state along the axial direction of the tower body, and the UV lamps (4-1) are fixed on the tower wall through lamp racks.

8. The system for flue gas purification using seawater according to claim 2, wherein One or more than one intermediate electrolytic oxygen production zone (17) or one or more than one intermediate UV photolysis zone is arranged between the first alkaline seawater spraying zone (6) and the chlorine gas filling zone (7), and at least one intermediate electrolytic oxygen production zone (17) is arranged below each intermediate UV photolysis zone.

9. The system for flue gas purification using seawater according to any one of claims 1 to 8, characterized in that, The first electrolytic oxygen production zone (5) and the second electrolytic oxygen production zone (9) each comprise catalytic electrolysis packing, and the catalytic electrolysis packing comprises titanium metal packing and a catalytic electrolysis layer sprayed on the titanium metal packing.

10. The system for flue gas purification using seawater according to claim 9, wherein The structure of the titanium metal packing is selected from 250Y, a Raschig ring or a Pall ring.

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