Flue gas water lifting and conditioning system

Abstract

The utility model provides a flue gas water lifting and conditioning system which comprises a flue gas water lifting device, the flue gas water lifting device is provided with a water outlet, and the water outlet is sequentially connected with a first pump body, a filter and electric adsorption equipment; the flue gas water lifting and conditioning system further comprises an air compressor, the air compressor is connected with the filter and used for reverse cleaning of the filter, and a first water pool and a water tank are arranged at the outlet end of the electro-adsorption equipment and used for collecting regenerated strong brine and a conditioned water body respectively. According to the utility model, the electro-adsorption equipment is used for flue gas water lifting and tempering for the first time, the pH value of flue gas water lifting treated by the electro-adsorption equipment tends to be neutral, the salt content is low, and the water vapor quality of a unit thermodynamic system cannot be influenced by direct reuse; the filter is arranged in front of the electro-adsorption equipment to ensure that the inlet water quality of the electro-adsorption equipment is stable, and meanwhile, the air compressor connected with the filter is used for periodically cleaning the filter to ensure that the whole system stably and reliably runs.

Description

Technical Field

[0001] The utility model relates to the technical field of tail gas treatment in power plants, in particular to a flue gas water extraction and conditioning system. Background Art

[0002] Thermal power generation is a high water consumption industry, accounting for 20% of all industrial water consumption. Water issues have become a constraint on the construction and development of the power industry in northern China.

[0003] At present, more than 90% of the flue gas desulfurization of coal-fired boilers in thermal power generation enterprises and other chemical enterprises adopts the wet desulfurization process of limestone gypsum method. The wet desulfurization process consumes a lot of water. Taking coal-fired power plants as an example, the water consumption of the wet desulfurization process accounts for more than 60% of the total water consumption of air-cooled units in the whole plant. Using the flue gas after wet desulfurization to extract water is the only way for power plants to save water and reduce consumption.

[0004] Since the flue gas at the outlet of the wet flue gas desulfurization process contains a small amount of acidic gases such as SO3 and SO2 and droplets carrying dissolved corrosive ions such as sulfate and chloride ions, the recovered water from the flue gas extraction generally has a low pH (about 2.0-3.0), SO4 2- Due to its high content, it cannot be used directly in production and life. The prior art usually uses the double alkali method to condition the extracted water, but there is a problem that the conditioning process requires the consumption of a large amount of sodium hydroxide and sodium carbonate, resulting in high operating costs. For this reason, the Chinese patent application number 202320487893.1 discloses a flue gas water conditioning system for a coal-fired power plant, including a connected storage tank, a water supply pump, a fluidized bed reactor, a sedimentation tank and a conditioning product tank; the bottom of the sedimentation tank is connected to the fluidized bed reactor through a circulating pump; the fluidized bed reactor includes a body, a water inlet pipe, a water outlet pipe, a water distributor and an air stripping device; a compressed air pipe is provided in the air stripping device; a filler is provided in the body, and the filler is a calcium carbonate filler. This solution can save about 70% of the operating costs, but the final purified water has a high salt content, and after reuse, it may still have an adverse effect on the water vapor quality of the unit's thermal system.

[0005] In view of this, the present utility model is proposed. Utility Model Content

[0006] The problem solved by the utility model is that the existing flue gas water extraction and conditioning method leads to high salt content of collected water, which may affect the water vapor quality of the unit thermal system after reuse.

[0007] In order to solve the above problems, the utility model provides a flue gas water lifting and conditioning system, including a flue gas water lifting device, the flue gas water lifting device has a water outlet, and the water outlet is connected to a first pump body, a filter, and an electric adsorption device in sequence; the flue gas water lifting and conditioning system also includes an air compressor, which is connected to the filter and is used for reverse cleaning of the filter. A first water pool and a water tank are arranged at the outlet end of the electric adsorption device, which are respectively used to collect regenerated concentrated brine and conditioned water.

[0008] The utility model arranges a filter in front of the electric adsorption device and uses an air compressor to regularly reverse clean the filter to ensure that the turbidity of the water entering the electric adsorption device meets the standard. After the electric adsorption device is energized, an electric field is generated, and anions, cations and charged particles in the water body will undergo directional migration and be adsorbed onto electrode plates of opposite electrical properties. When the electrode plates are saturated with adsorption, desorption can occur by reversing the electrodes or short-circuiting the electrodes. The adsorbed ions will be released back into the solution to form regenerated concentrated brine, and the regenerated concentrated brine is discharged into the first water pool to achieve regeneration of the electric adsorption device, thereby ensuring continuous and stable operation of the entire flue gas water lifting and conditioning system.

[0009] Preferably, the flue gas water conditioning system further comprises a second pump body and a second water tank, and the second pump body and the second water tank are respectively connected to the filter. When the turbidity of the water outlet of the filter exceeds the standard, the backwashing process is started, and the air compressor is used for air scrubbing and the second pump body is used for water backwashing. The wastewater generated by backwashing is drained to the second water tank to ensure the continuous and stable operation of the entire flue gas water conditioning system.

[0010] Preferably, the electrosorption device includes a connected adsorption module and a power supply system, and the adsorption module includes two parallel electrode plates, and the plane where the electrode plates are located is parallel to the flow direction of water in the electrosorption device. This arrangement generates an electric field between the two electrode plates after the current is applied, and when the water body with anions, cations and charged particles flows through the electrode plates, the anions, cations and charged particles will migrate in a directional manner, wherein the cations are adsorbed to the surface of the negative electrode plate, and the anions are adsorbed to the surface of the positive electrode plate.

[0011] Preferably, the electrosorption device further comprises a detection module for detecting the conductivity, temperature, flow rate, inlet and outlet water pressure of the water body in the electrosorption device. This setting can monitor the operation of the electrosorption device in real time to ensure stable and reliable operation.

[0012] Preferably, the flue gas water lifting device includes an absorption condensation tower and a water reservoir. The absorption condensation tower includes an air lift plate, a second turbulator, a second spray layer, and a second tube bundle dust collector arranged in sequence from bottom to top. The outlet end of the air lift plate is connected to the water reservoir. A mechanical ventilation tower and a third pump body are arranged in sequence between the water reservoir and the inlet end of the second spray layer. The mechanical ventilation tower is used for heat exchange and cooling of the water body.

[0013] This arrangement allows the flue gas after desulfurization to pass through the air lift plate and the second turbulator to evenly distribute the flue gas, and then undergo intensive gas-liquid contact and mixing with the cooling circulating water sprayed from the second spray layer to achieve cooling. The clean flue gas after cooling continues to contact with the spray liquid, and most of the fine droplets are captured and fall together with the spray liquid and eventually enter the water reservoir. The recovered water in the water reservoir is conditioned by adding chemicals, and then pumped to the mechanical ventilation tower through the third pump body to be cooled to 40°C again, and re-transported to the second spray layer as a cooling medium.

[0014] Preferably, the absorption and condensation tower also includes a first tube bundle dust collector located at the lower side of the air lift plate, and a first spray layer and a first turbulator are sequentially arranged at the lower side of the first tube bundle dust collector. A slurry pool is arranged at the bottom of the absorption and condensation tower, and the first turbulator is located above the slurry pool.

[0015] This setting divides the absorption and condensation tower into a lower desulfurization zone and an upper water collection zone. After the high-temperature flue gas enters the absorption and condensation tower, it is desulfurized by a limestone-gypsum wet process. The first turbulator is used for flue gas uniform flow and gas-liquid-solid three-phase liquid mass transfer, thereby increasing the contact area of ​​the spray and enhancing the absorption of sulfides.

[0016] Preferably, the flue gas water extraction device further comprises a connected generator set, an induced draft fan, and a low-temperature economizer, and the outlet of the low-temperature economizer is connected to the inlet of the absorption and condensation tower. This arrangement can reduce the temperature of the generated flue gas, is more energy-saving and has high space utilization.

[0017] Compared with the prior art, the flue gas water conditioning system described in the embodiment of the utility model has the following beneficial effects: 1) The utility model uses the electric adsorption device for flue gas water conditioning for the first time. The pH of the flue gas water after being treated by the electric adsorption device tends to be neutral and has a low salt content, which will not affect the water vapor quality of the unit thermal system; 2) A filter is set at the inlet end in front of the electric adsorption device to stabilize the water quality of the inlet water of the electric adsorption device, and the air compressor connected to the filter can realize regular cleaning of the filter to ensure stable and reliable operation of the entire system; 3) The absorption and condensation tower can realize desulfurization and water collection at the same time, which is beneficial to improving the water quality of water extracted from the flue gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the flue gas water extraction and conditioning system according to an embodiment of the utility model;

[0019] Figure 2 This is a schematic diagram of the structure of the flue gas water extraction device according to an embodiment of the utility model;

[0020] Figure 3 It is a schematic diagram of the structure of the absorption and condensation tower described in an embodiment of the utility model.

[0021] Description of reference numerals:

[0022] 1-filter; 2-electric adsorption equipment; 3-first pump body; 4-second pump body; 5-flue gas water lifting device; 51-absorption condensation tower; 511-slurry pool; 512-air lift plate; 513-first turbulator; 514-first spray layer; 515-first tube bundle dust collector; 516-second turbulator; 517-second tube bundle dust collector; 518-second spray layer; 52-water reservoir; 53-mechanical ventilation tower; 54-third pump body; 55-generator set; 56-low-temperature economizer; 57-induced draft fan; 6-air compressor; 7-first water tank; 8-second water tank; 9-water tank. DETAILED DESCRIPTION

[0023] In order to make the above-mentioned purposes, features and advantages of the utility model more obvious and easy to understand, the specific embodiments of the utility model are described in detail below with reference to the accompanying drawings. Under the premise of different conflicts, the technical features in the embodiments of the utility model can be combined with each other.

[0024] It should be noted that if there are directional indications (such as up, down, left, right, front, back, etc.) involved in this embodiment, the directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0025] In addition, if there are descriptions involving "first", "second", etc. in this embodiment, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by this utility model.

[0026] In this embodiment, the term "includes", "comprising" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprising..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0027] At present, most of the domestic wet flue gas desulfurization devices have cancelled the gas-to-gas heat exchanger (GGH). The clean flue gas at the desulfurization outlet is saturated wet flue gas with a temperature of about 45℃-60℃. If it is directly discharged into the atmosphere, it will cause a waste of resources. Based on the principle of phase change condensation of wet saturated water vapor under different partial pressures, the use of the wet saturation or supersaturation conditions of the flue gas after desulfurization to achieve flue gas water extraction by cooling has become one of the important ways to solve the problem of water conservation in coal-fired power plants. Since the flue gas contains acidic gases such as SO3 and SO2, the pH of the recycled water produced by flue gas water extraction is low and SO4 2- The content is high and needs to be conditioned before it can be reused; the existing double alkali method for water conditioning is costly and the operating pressure of the subsequent replenishment water treatment is high. The electrosorption technology is a method that uses potential difference as a driving force to promote the adsorption of ions on the surface of the charged electrode. It is currently a typical desalination method with advantages. How to use electrosorption to continuously and stably condition the flue gas water extraction is obviously of great significance. To this end, the applicant proposes the following technical solution:

[0028] like Figure 1-3 As shown, a flue gas water lifting and conditioning system includes a flue gas water lifting device 5, the flue gas water lifting device 5 has a water outlet, and the water outlet is connected to the first pump body 3, the filter 1, and the electric adsorption device 2 in sequence; the flue gas water lifting and conditioning system also includes an air compressor 6, the air compressor 6 is connected to the filter 1, and is used for reverse cleaning of the filter 1. The outlet end of the electric adsorption device 2 is provided with a first water pool 7 and a water tank 9, which are respectively used to collect regenerated concentrated brine and conditioned water.

[0029] This setting can use the air compressor 6 to regularly reverse clean the filter 1 to ensure that the turbidity of the water entering the electric adsorption device 2 meets the standard. When the electric adsorption device 2 is powered on, an electric field is generated, and the anions and cations and charged particles in the water will migrate in a directional manner and be adsorbed onto the electrode plates of opposite electrical properties. When the electrode plates are saturated with adsorption, desorption can occur by reversing the electrodes or short-circuiting the electrodes. The adsorbed ions will be released back into the solution to form regenerated concentrated brine, which is then discharged into the first water tank 7 to achieve the regeneration of the electric adsorption device 2, ensuring the continuous and stable operation of the entire flue gas water conditioning system. The total hardness, Ca 2+ and Mg 2+ The removal rates of Na + The removal rate can reach 94.74%, Cl - The removal rate can reach 85.71%, SO4 2- The removal rate can reach 86%.

[0030] Preferably, the flue gas water conditioning system further comprises a second pump body 4 and a second water tank 8, and the second pump body 4 and the second water tank 8 are respectively connected to the filter 1. When the turbidity of the water outlet of the filter 1 exceeds the standard, the backwashing process is started, and the air compressor 6 is used for air scrubbing and the second pump body 4 is backwashed with water. The wastewater generated by the backwashing is drained to the second water tank 8, so as to ensure the continuous and stable operation of the whole flue gas water conditioning system.

[0031] As an example of the present invention, the electric adsorption device 2 includes a connected adsorption module and a power supply system, and the adsorption module includes two parallel electrode plates, and the plane where the electrode plates are located is parallel to the flow direction of water in the electric adsorption device 2. After the current is applied, an electric field is generated between the two electrode plates, and when the water body with anions, cations and charged particles flows through the electrode plates, the anions, cations and charged particles will migrate in a directional manner, wherein the cations are adsorbed to the surface of the negative electrode plate, and the anions are adsorbed to the surface of the positive electrode plate.

[0032] The electrosorption device 2 also includes a detection module for detecting the conductivity, temperature, flow rate, inlet and outlet water pressure, voltage and current of the water body in the electrosorption device 2. The operation of the electrosorption device 2 includes three stages: pre-flushing, water collection, and regeneration. In the pre-flushing stage, raw water is used to discharge the concentrated water remaining in the adsorption module and part of the pipeline during the electrode regeneration stage. In the water collection stage, the adsorption module is used to adsorb ions in the raw water, so that the salts in the raw water are enriched and concentrated on the electrode surface. The water after deionization is discharged to the water tank 9. In the regeneration stage, the adsorbed ions are desorbed and discharged into the first water pool 7, and then the system automatically enters the next cycle. The electrosorption device 2 can be provided with a plurality of adsorption modules in parallel. This setting can increase the water volume and improve the ion removal efficiency.

[0033] As an example of the present utility model, the flue gas water lifting device 5 includes an absorption and condensation tower 51 and a water reservoir 52. The absorption and condensation tower 51 includes an air lift plate 512, a second turbulator 516, a second spray layer 518, and a second tube bundle dust collector 517 arranged in sequence from bottom to top. The outlet end of the air lift plate 512 is connected to the water reservoir 52. A mechanical ventilation tower 53 and a third pump body 54 are arranged in sequence between the water reservoir 52 and the inlet end of the second spray layer 518. The mechanical ventilation tower 53 is used to exchange heat and cool the water body. After desulfurization, the flue gas passes through the air lift plate 512 and the second turbulator 516 to evenly distribute the flue gas, and then undergoes intensive gas-liquid contact and mixing with the cooling circulating water (water temperature is about 40°C) sprayed from the second spray layer 518 to achieve cooling. The clean flue gas after cooling continues to contact with the spray liquid, and most of the fine droplets are captured and fall together with the spray liquid and eventually enter the water reservoir 52. The recovered water in the water reservoir 52 is conditioned by adding chemicals, and then pumped to the mechanical ventilation tower 53 through the third pump body 54 to be cooled to 40°C again, and then re-transported to the second spray layer 518 as a cooling medium.

[0034] Preferably, the flue gas water extraction device 5 further includes a connected generator set 55, an induced draft fan 57, and a low-temperature economizer 56, wherein the outlet of the low-temperature economizer 56 is connected to the inlet of the absorption and condensation tower 51. This arrangement can reduce the temperature of the generated flue gas, is more energy-saving and has high space utilization.

[0035] Preferably, the absorption condensation tower 51 further comprises a first tube bundle dust collector 515 located at the lower side of the air lift plate 512, a first spray layer 514 and a first turbulator 513 are sequentially arranged at the lower side of the first tube bundle dust collector 515, a slurry pool 511 is arranged at the bottom of the absorption condensation tower 51, and the first turbulator 513 is located above the slurry pool 511. This arrangement divides the absorption condensation tower 51 into a lower desulfurization zone and an upper water collection zone. After the 105°C raw flue gas enters the absorption condensation tower 51, it is subjected to limestone-gypsum wet process desulfurization. The first turbulator 513 is used for flue gas uniform flow and gas-liquid-solid three-phase liquid holding mass transfer, thereby increasing the contact area of ​​the spray, enhancing the absorption of sulfides, and achieving the SO2 content in the flue gas from the inlet 3538mg / Nm 3 (standard dry basis 6% oxygen, coal sulfur content 1.2%) reduced to 20mg / Nm 3 (6% oxygen on a standard dry basis), the desulfurization efficiency reaches 99.5%, and the first tube bundle dust collector 515 can remove dust and gypsum droplets entrained in the flue gas, ensuring that the dust content in the desulfurized flue gas is less than 5mg / Nm 3 , which is beneficial to improve the water quality of water extracted from flue gas.

[0036] Although the utility model is disclosed as above, the utility model is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the utility model. Therefore, the protection scope of the utility model shall be subject to the scope defined by the claims.

Claims

1. A flue gas water extraction and conditioning system, characterized in that: The invention comprises a flue gas water extraction device (5), wherein the flue gas water extraction device (5) has a water outlet, wherein the water outlet is connected to a first pump body (3), a filter (1), and an electric adsorption device (2) in sequence; the flue gas water extraction and conditioning system also comprises an air compressor (6), wherein the air compressor (6) is connected to the filter (1) and is used for reverse cleaning of the filter (1); a first water pool (7) and a water tank (9) are arranged at the outlet end of the electric adsorption device (2), which are used for collecting regenerated concentrated brine and conditioned water, respectively.

2. The flue gas water extraction and conditioning system according to claim 1, characterized in that: The flue gas water extraction and conditioning system further comprises a second pump body (4) and a second water pool (8), wherein the second pump body (4) and the second water pool (8) are respectively connected to the filter (1).

3. The flue gas water extraction and conditioning system according to claim 1, characterized in that: The electric adsorption device (2) comprises a connected adsorption module and a power supply system, the adsorption module comprises two parallel electrode plates, and the planes on which the electrode plates are located are parallel to the flow direction of water in the electric adsorption device (2).

4. The flue gas water extraction and conditioning system according to claim 3, characterized in that: The electric adsorption device (2) further comprises a detection module, which is used to detect the conductivity, temperature, flow rate, and inlet and outlet water pressure of the water body within the electric adsorption device (2).

5. The flue gas water extraction and conditioning system according to claim 1, characterized in that: The flue gas water lifting device (5) comprises an absorption condensation tower (51) and a water reservoir (52); the absorption condensation tower (51) comprises an air lift plate (512), a second turbulator (516), a second spray layer (518), and a second tube bundle dust collector (517) which are arranged in sequence from bottom to top; the outlet end of the air lift plate (512) is connected to the water reservoir (52); a mechanical ventilation tower (53) and a third pump body (54) are arranged in sequence between the water reservoir (52) and the inlet end of the second spray layer (518); the mechanical ventilation tower (53) is used for heat exchange and cooling of water.

6. The flue gas water extraction and conditioning system according to claim 5, characterized in that: The absorption and condensation tower (51) further comprises a first tube bundle dust collector (515) located at the lower side of the air lift plate (512), a first spray layer (514) and a first turbulator (513) are sequentially arranged at the lower side of the first tube bundle dust collector (515), a slurry pool (511) is arranged at the bottom of the absorption and condensation tower (51), and the first turbulator (513) is located above the slurry pool (511).

7. The flue gas water extraction and conditioning system according to claim 5, characterized in that: The flue gas water extraction device The device (5) also includes a connected generator set (55), an induced draft fan (57), and a low-temperature economizer (56). The outlet of the low-temperature economizer (56) is connected to the inlet of the absorption and condensation tower (51).

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