Thermal power plant desulfurization wastewater treatment device

Abstract

The utility model provides a thermal power plant desulfurization wastewater treatment device which comprises a boiler, the boiler comprises a boiler body and a flue communicated with the boiler body, the flue is sequentially connected with a desulfurization tower and a discharge chimney, and a flue gas heat exchanger is arranged in the flue; a dust remover is arranged on the flue between the flue gas heat exchanger and the boiler body; the heat exchanger is connected with the wastewater evaporation device; the desulfurization tower is connected with the desulfurization wastewater pretreatment device; and the wastewater evaporation device is also connected with the desulfurization wastewater pretreatment device. According to the device, the heat exchanger is arranged in the flue, the heat exchange medium in the heat exchanger is used for absorbing heat of flue gas, meanwhile, the temperature of the heat exchange medium is increased, and the heated heat exchange medium is used for heating desulfurization wastewater pretreated by the desulfurization wastewater pretreatment device; according to the device, the desulfurization wastewater is treated in an indirect heating evaporation mode, and the defect that the boiler flue is corroded due to the fact that the desulfurization wastewater is directly sprayed into the flue is overcome.

Description

Technical Field

[0001] This application relates to the field of wastewater treatment technology in thermal power plants, and in particular to a device for treating desulfurization wastewater from thermal power plants. Background Technology

[0002] Thermal power generation is the main power generation mode in my country. Due to energy constraints, my country's thermal power plants are basically coal-fired power plants that use coal as their energy source. However, due to the complex composition of coal, the sulfur element in it produces pollutants, mainly sulfur dioxide, during combustion. If the sulfur dioxide emission exceeds the standard, it can easily lead to the formation of acid rain, which causes serious damage to the environment and buildings. Therefore, it is necessary to remove sulfur dioxide from flue gas. The existing methods for treating sulfur dioxide in flue gas are mainly wet desulfurization, among which calcium desulfurization is the most commonly used. This method uses lime milk as a desulfurizing agent to spray and wash the sulfur-containing flue gas in the desulfurization tower, and forces air into the tower to oxidize the generated calcium sulfite to form calcium sulfate precipitate, i.e., gypsum. The mixed gypsum is then absorbed and filtered by hydraulic pressure for solid-liquid separation. The obtained gypsum is sold as a by-product, while the filtrate, i.e., desulfurization wastewater, needs to be treated before discharge or reuse.

[0003] The existing treatment routes for desulfurization wastewater mainly involve sedimentation-flocculation-multi-stage filtration-ultrafiltration-reverse osmosis. However, this method is not only lengthy, but also still generates a certain amount of "concentrated water" during the reverse osmosis process, which still needs to be treated. Therefore, there is also a method that utilizes the high temperature of the flue gas to evaporate the wastewater. This method involves spraying the wastewater into the flue gas, where the high temperature evaporates the water, achieving the purpose of wastewater treatment. However, wet desulfurization wastewater from coal-fired power plants generally contains large amounts of salt, sulfate ions, heavy metal ions, and chloride ions, as well as relatively difficult-to-treat COD. The pH value is generally between 5 and 6, making the water weakly acidic and corrosive to the structures within the flue gas ducts, thus limiting its application. Utility Model Content

[0004] This application provides a desulfurization wastewater treatment device for thermal power plants to solve the problem of wastewater corrosion on the flue when the high temperature of the flue is used to evaporate the wastewater.

[0005] This application provides a desulfurization wastewater treatment device for thermal power plants, including a boiler. The boiler includes a boiler body and a flue connected to the boiler body. The flue is connected in sequence to a desulfurization tower and an exhaust chimney. A flue gas heat exchanger is installed in the flue.

[0006] A dust collector is installed on the flue between the flue gas heat exchanger and the boiler body.

[0007] The heat exchanger is connected to the wastewater evaporation device, and the desulfurization tower is connected to the desulfurization wastewater pretreatment device.

[0008] The wastewater evaporation unit is also connected to the desulfurization wastewater pretreatment unit.

[0009] Optionally, the heat exchanger is connected to the wastewater evaporation device via hot water pipes and cold water pipes;

[0010] An expansion tank is also installed on the cold water pipe;

[0011] A transfer pump is installed on the hot water pipe.

[0012] Optionally, the desulfurization wastewater pretreatment device includes a sedimentation tank, a flocculation sedimentation tank, a first filter, and a clear liquid storage tank connected in series.

[0013] The sedimentation tank is also connected in sequence to the filter press and the flocculation sedimentation tank;

[0014] The sedimentation tank is connected to the desulfurization tower.

[0015] Optionally, the wastewater evaporation device includes a heating evaporator, a condenser, and a vacuum unit connected in sequence;

[0016] The condenser is connected to the condensate storage tank;

[0017] The heating evaporator is also connected to the clear liquid storage tank and the crystallization pool, respectively.

[0018] Optionally, the heated evaporator includes a heating chamber and an evaporation chamber;

[0019] The evaporation chamber is positioned at a high level, and the heating chamber is connected to the lower part of the evaporation chamber via a circulation pump. The output end of the circulation pump is also connected to the crystallization tank.

[0020] The bottom of the evaporation chamber is connected to the top of the heating chamber via a throttling valve, and the top of the evaporation chamber is connected to the condenser and the vacuum unit in sequence.

[0021] The top of the heating chamber is connected to the evaporation chamber via a balance pipe;

[0022] The heating chamber is also connected to the clear liquid storage tank via a first valve and to the crystallization pool via a second valve.

[0023] Optionally, a heat exchange coil is installed inside the heating chamber, with the lower end of the heat exchange coil extending out of the heating chamber and connected to a hot water pipe, and the upper end extending out of the heating chamber and connected to a cold water pipe.

[0024] The heating chamber has an inlet at the top, which is connected to the clear liquid storage tank and the crystallization tank respectively. The bottom has a circulation port, which is connected to the bottom of the evaporation chamber via a circulation pump.

[0025] Optionally, a spray layer connected to a circulating pump is provided in the lower part of the evaporation chamber, and the spraying direction of the spray layer is upward.

[0026] The bottom of the evaporation chamber is equipped with a drain port, which is connected to the inlet port through a throttle valve.

[0027] The desulfurization wastewater treatment device for thermal power plants provided in this application utilizes a heat exchanger installed within the flue gas duct. The heat exchange medium within the heat exchanger absorbs heat from the flue gas, simultaneously raising its temperature. This heated medium then heats the desulfurization wastewater that has undergone pretreatment in the desulfurization wastewater pretreatment device. This device treats the desulfurization wastewater through indirect heating and evaporation, overcoming the drawbacks of directly spraying desulfurization wastewater into the flue gas duct, which causes corrosion. Furthermore, the dust collector in this application is installed in the flue gas duct before the flue gas enters the heat exchanger. This reduces the deposition of particulate matter such as dust in the boiler flue gas on the heat exchanger, extends the cleaning cycle of the heat exchanger's outer surface, and reduces the adverse consequences of decreased heat exchange efficiency caused by dust accumulation on the heat exchanger surface. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 A schematic diagram of a desulfurization wastewater treatment device for a thermal power plant provided in an embodiment of this application;

[0030] Figure 2 A schematic diagram of a desulfurization wastewater treatment device for a thermal power plant provided in another embodiment of this application;

[0031] Figure 3 This is a schematic diagram of a desulfurization wastewater pretreatment device provided in an embodiment of this application;

[0032] Figure 4 This is a schematic diagram of a wastewater evaporation device provided in an embodiment of this application;

[0033] Figure 5 This is a schematic diagram of a wastewater evaporation device provided in another embodiment of this application.

[0034] Explanation of reference numerals in the attached figures:

[0035] 1. Boiler; 2. Desulfurization tower; 3. Exhaust chimney; 4. Heat exchanger; 5. Wastewater evaporation device; 6. Desulfurization wastewater pretreatment device; 7. Expansion tank; 10. Hot water pipe; 11. Boiler body; 12. Flue; 13. Dust collector; 20. Cold water pipe; 30. Transfer pump; 51. Heating evaporator; 52. Condenser; 53. Vacuum unit; 54. Condensate storage tank; 55. Crystallization tank; 61. Sedimentation tank; 62. Flocculation sedimentation tank; 63. First filter; 64. Clear liquid storage tank; 65. Filter press; 100. Throttling valve; 510. Circulation pump; 511. Heating chamber; 512. Evaporation chamber; 513. Balance pipe; 5100. First valve; 5101. Liquid inlet; 5102. Circulation port; 5103. Liquid outlet; 5111. Heat exchange coil; 5121. Spray layer; 5200. Second valve. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application are described clearly and completely below. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are also within the scope of protection of this application.

[0037] like Figure 1 As shown, this application provides a desulfurization wastewater treatment device for a thermal power plant, including a boiler 1. The boiler 1 includes a boiler body 11 and a flue 12 connected to the boiler body 11. The flue 12 is connected in sequence to a desulfurization tower 2 and an exhaust chimney 3. A flue gas heat exchanger 4 is installed in the flue 12.

[0038] A dust collector 13 is installed on the flue 12 between the flue heat exchanger 4 and the boiler body 11.

[0039] Heat exchanger 4 is connected to wastewater evaporation device 5, and desulfurization tower 2 is connected to desulfurization wastewater pretreatment device 6;

[0040] The wastewater evaporation device 5 is also connected to the desulfurization wastewater pretreatment device 6.

[0041] During operation, the flue gas generated by fuel combustion in the boiler body 11 is discharged into the flue 12. After denitrification and heat exchange, its temperature drops to approximately 150°C. After dust removal by the dust collector 13, it passes through the heat exchanger 4 located in the flue 12 to heat the medium (purified water or thermal oil) inside the heat exchanger 4. The heated medium then enters the wastewater evaporation device 5 to evaporate the desulfurization wastewater. The temperature of the flue gas after heat exchange is further reduced, and it then enters the desulfurization tower 2 for desulfurization. The desulfurized flue gas can be discharged into the exhaust chimney 3. The desulfurization wastewater generated during the desulfurization process is pretreated in the desulfurization wastewater pretreatment device 6 before being fed into the wastewater evaporation device 5.

[0042] The desulfurization wastewater treatment device for thermal power plants provided in this application utilizes a heat exchanger 4 installed within the flue 12. The heat exchange medium within the heat exchanger 4 absorbs heat from the flue gas, simultaneously raising its temperature. This heated medium then heats the desulfurization wastewater that has undergone pretreatment by the desulfurization wastewater pretreatment device 6. This device treats the desulfurization wastewater through indirect heating and evaporation, overcoming the drawbacks of directly spraying desulfurization wastewater into the flue, which causes corrosion of the boiler flue. Furthermore, the dust collector in this application is installed on the flue before the flue gas enters the heat exchanger 4. This reduces the deposition of particulate matter such as dust in the boiler flue gas on the heat exchanger 4, extends the cleaning cycle of the outer surface of the heat exchanger 4, and reduces the adverse consequences of decreased heat exchange efficiency caused by dust accumulation on the surface of the heat exchanger 4.

[0043] like Figure 2 As shown, optionally, the heat exchanger 4 and the wastewater evaporation device 5 are connected by a hot water pipe 10 and a cold water pipe 20;

[0044] An expansion tank 7 is also installed on the cold water pipe 20;

[0045] A liquid transfer pump 30 is installed on the hot water pipe 10.

[0046] In this application, an expansion tank 7 is installed on the cold water pipe 20, which can play a role in buffering and stabilizing pressure, and can also replenish the heat exchange medium to the heat exchange system through the expansion tank 7.

[0047] like Figure 3 As shown, optionally, the desulfurization wastewater pretreatment device 6 includes a sedimentation tank 61, a flocculation sedimentation tank 62, a first filter 63 and a clear liquid storage tank 64 connected in series.

[0048] Sedimentation tank 61 is also connected in sequence to filter press 65 and flocculation sedimentation tank 62;

[0049] Sedimentation tank 61 is connected to desulfurization tower 2.

[0050] In this application, when the desulfurization wastewater is pretreated in the desulfurization wastewater pretreatment device 6, the desulfurization liquid saturated with absorbent output from the desulfurization tower 2 is fed into the sedimentation tank 61 for sedimentation. The supernatant after sedimentation is transferred to the flocculation sedimentation tank 62. First, the pH of the supernatant is tested. If the pH of the supernatant is not within the optimal range for flocculant addition, an acid-base adjuster (sodium hydroxide can be used for alkaline reagents, and sulfuric acid, hydrochloric acid, etc. can be used for acidic reagents) is used to adjust the pH of the supernatant to between 6 and 7.5. Then, a flocculant (often a combination of polyaluminum chloride and polyacrylamide is used) is added to the sedimentation tank 61 to flocculate and settle the supernatant to remove suspended solids. The settled wastewater is then filtered through the filter 63 and transferred to the clear liquid storage tank 64. The precipitate in sedimentation tank 61 is gypsum. After being filtered by filter press 65, the filtrate is transferred to flocculation sedimentation tank 62 and treated together with the supernatant. The filter cake obtained by filtration can be transferred to the corresponding gypsum storage silo for further processing.

[0051] like Figure 4 As shown, optionally, the wastewater evaporation device 5 includes a heating evaporator 51, a condenser 52 and a vacuum unit 53 connected in sequence;

[0052] Condenser 52 is connected to condensate storage tank 54;

[0053] The heating evaporator 51 is also connected to the clear liquid storage tank 64 and the crystallization pool 55 respectively.

[0054] In this application, a vacuum unit 53 is used to evacuate the heating evaporator 51 (to a negative pressure of -0.06MPa to -0.09MPa) to lower the boiling point of water, thereby saving energy and facilitating water evaporation.

[0055] like Figure 5 As shown, optionally, the heating evaporator 51 includes a heating chamber 511 and an evaporation chamber 512;

[0056] The evaporation chamber 512 is positioned at a high level, and the heating chamber 511 is connected to the lower part of the evaporation chamber 512 via a circulation pump 510. The output end of the circulation pump 510 is also connected to the crystallization tank 55.

[0057] The bottom of the evaporation chamber 512 is connected to the top of the heating chamber 511 via a throttle valve 100, and the top of the evaporation chamber 512 is connected to the condenser 52 and the vacuum unit 53 in sequence.

[0058] The top of the heating chamber 511 is connected to the evaporation chamber 512 via a balance pipe 513;

[0059] The heating chamber 511 is also connected to the clear liquid storage tank 64 via the first valve 5100 and to the crystallization pool 55 via the second valve 5200.

[0060] like Figure 5As shown, optionally, a heat exchange coil 5111 is provided inside the heating chamber 511. The lower end of the heat exchange coil 5111 extends out of the heating chamber 511 and is connected to the hot water pipe 10, and the upper end extends out of the heating chamber 511 and is connected to the cold water pipe 20.

[0061] The heating chamber 511 has a liquid inlet 5101 at the top, which is connected to the clear liquid storage tank 64 and the crystallization pool 55 respectively. The lower part has a circulation port 5102, which is connected to the lower part of the evaporation chamber 512 through the circulation pump 510.

[0062] In this application, the evaporation chamber 512 is positioned at a high level, which facilitates the natural return of hot water that fails to evaporate in the evaporation chamber 512 to the heating chamber 511.

[0063] In this application, a seal is provided at the position where the heat exchange coil 5111 protrudes from the heating chamber 511 (for example, by using sealant, or by welding the heat exchange coil 5111 to the heating chamber 511 at the protrusion position to achieve the purpose of preventing water leakage; these methods are all existing technologies and will not be described in detail here).

[0064] In use, the pretreated wastewater stored in the clear liquid storage tank 64 is fed into the heating chamber 51 through the first valve 5100 until it covers the heat exchange coil 5111. (When adding pretreated wastewater to the heating chamber 51, the second valve 5200 and the throttle valve 100 can be closed and the first valve 5100 can be opened. The vacuum unit 53 can be turned on to draw a vacuum. Since the evaporation chamber 512 and the heating chamber 511 are connected through the balance pipe 513, the evaporation chamber 512 and the heating chamber 511 can be drawn into a negative pressure state at this time, and the pretreated wastewater in the clear liquid storage tank 64 will be drawn into the heating chamber 51.) Simultaneously, the transfer pump 30 is turned on, allowing the low-temperature medium in the heat exchange coil 5111 to enter the heat exchanger 4 (the structure of the heat exchanger 4 is a multi-layer coiled heat exchange tube, the specific structure of which can be referred to as the economizer) located in the flue 12 for heating. The heated medium then enters the heat exchange coil 5111 to heat the wastewater in the heating chamber 51. The heated medium is then output from the heat exchange coil 5111 and enters the heat exchanger 4 through the cold water pipe 20 to absorb the flue gas temperature and increase its temperature. This cycle continues.

[0065] like Figure 5 As shown, optionally, a spray layer 5121 connected to a circulating pump 510 is provided in the lower part of the evaporation chamber 512, and the spraying direction of the spray layer 5121 is upward spraying;

[0066] The bottom of the evaporation chamber 512 is provided with a drain port 5103, which is connected to the inlet port 5101 through a throttle valve 100.

[0067] The desulfurization wastewater heated in heating chamber 51 is then transferred to spray layer 5121 in evaporation chamber 512 by circulating pump 510 and sprayed upward. As the vacuum unit 53 evacuates evaporation chamber 512, the heated desulfurization wastewater (temperature of about 80~85℃) will evaporate to generate steam. The generated steam will be extracted from evaporation chamber 512 and enter condenser 52 for condensation. The condensate obtained is collected in condensate storage tank 54 for recycling.

[0068] The desulfurization wastewater sprayed into the evaporation chamber 512 is partially evaporated into steam, while the rest falls to the bottom of the evaporation chamber 512. From there, it flows into the heating chamber 511 through the opening of the throttle valve 100 for heating and evaporation. This increases the concentration of the desulfurization wastewater, meaning that each spray cycle concentrates the wastewater. When the wastewater reaches a certain concentration, the vacuum in the evaporation chamber 512 is broken, and the concentrated wastewater is transferred to the crystallization tank 55 via a circulation pump for crystallization. The resulting mother liquor can then be transferred to the heating chamber 511 through the second valve 5200 for further evaporation.

[0069] A desulfurization wastewater treatment device for thermal power plants operates as follows:

[0070] During operation, the flue gas generated by fuel combustion in the boiler body 11 is discharged into the flue 12. After denitrification and heat exchange, its temperature drops to approximately 150°C. After dust removal by the dust collector 13, it passes through the heat exchanger 4 located in the flue 12 to heat the medium (purified water or thermal oil) inside the heat exchanger 4. The heated medium then enters the wastewater evaporation device 5 to evaporate the desulfurization wastewater. The temperature of the flue gas after heat exchange is further reduced, and it then enters the desulfurization tower 2 for desulfurization. The desulfurized flue gas can be discharged into the exhaust chimney 3. The desulfurization wastewater generated during the desulfurization process is pretreated in the desulfurization wastewater pretreatment device 6 before being fed into the wastewater evaporation device 5.

[0071] When the desulfurization wastewater undergoes pretreatment in the desulfurization wastewater pretreatment device 6, the desulfurization liquid saturated with absorbents from the desulfurization tower 2 is fed into the sedimentation tank 61 for sedimentation. The supernatant after sedimentation is transferred to the flocculation sedimentation tank 62. First, the pH of the supernatant is tested. If the pH of the supernatant is not within the optimal range for flocculant addition, an acid-base adjuster (since the supernatant is generally acidic, alkaline substances such as sodium hydroxide are often used to adjust the pH) is used to adjust the pH of the supernatant to between 6 and 7.5. Then, a flocculant (often a combination of polyaluminum chloride and polyacrylamide) is added to the sedimentation tank 61 to flocculate and settle the supernatant to remove suspended solids. The settled wastewater is then filtered through the filter 63 and transferred to the clear liquid storage tank 64. The precipitate in sedimentation tank 61 is gypsum. After being filtered by filter press 65, the filtrate is transferred to flocculation sedimentation tank 62 and treated together with the supernatant. The filter cake obtained by filtration can be transferred to the corresponding gypsum storage silo for further processing.

[0072] The pretreated wastewater stored in the clear liquid storage tank 64 is fed into the heating chamber 51 through the first valve 5100 until it covers the heat exchange coil 5111. (When adding pretreated wastewater to the heating chamber 51, the second valve 5200 and the throttle valve 100 can be closed and the first valve 5100 can be opened. The vacuum unit 53 can be turned on to draw a vacuum. Since the evaporation chamber 512 and the heating chamber 511 are connected through the balance pipe 513, the evaporation chamber 512 and the heating chamber 511 can be drawn into a negative pressure state at this time, and the pretreated wastewater in the clear liquid storage tank 64 will be drawn into the heating chamber 51.) Simultaneously, the transfer pump 30 is turned on, allowing the low-temperature medium in the heat exchange coil 5111 to enter the heat exchanger 4 (the structure of the heat exchanger 4 is a multi-layer coiled heat exchange tube, the specific structure of which can be referred to as the economizer) located in the flue 12 for heating. The heated medium then enters the heat exchange coil 5111 to heat the wastewater in the heating chamber 51. The heated medium is then output from the heat exchange coil 5111 and enters the heat exchanger 4 through the cold water pipe 20 to absorb the flue gas temperature and increase its temperature. This cycle continues.

[0073] The desulfurization wastewater heated in heating chamber 51 is then transferred to spray layer 5121 in evaporation chamber 512 by circulating pump 510 and sprayed upward. As the vacuum unit 53 evacuates evaporation chamber 512, the heated desulfurization wastewater (temperature of about 80~85℃) will evaporate to generate steam. The generated steam will be extracted from evaporation chamber 512 and enter condenser 52 for condensation. The condensate obtained is collected in condensate storage tank 54 for recycling.

[0074] The desulfurization wastewater sprayed into the evaporation chamber 512 is partially evaporated into steam, while the rest falls to the bottom of the evaporation chamber 512. From there, it flows into the heating chamber 511 through the opening of the throttle valve 100 for heating and evaporation. This increases the concentration of the desulfurization wastewater, meaning that each spray cycle concentrates the wastewater. When the wastewater reaches a certain concentration, the vacuum in the evaporation chamber 512 is broken, and the concentrated wastewater is transferred to the crystallization tank 55 via a circulation pump for crystallization. The resulting mother liquor can then be transferred to the heating chamber 511 through the second valve 5200 for further evaporation.

[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A flue gas desulfurization wastewater treatment apparatus for a thermal power plant, comprising a boiler (1) including a boiler body (11) and a flue (12) communicating with the boiler body (11), the flue (12) being connected to a desulfurization tower (2) and a discharge stack (3) in this order, characterized in that, A flue gas heat exchanger (4) is installed inside the flue (12). A dust collector (13) is installed on the flue (12) between the flue heat exchanger (4) and the boiler body (11). The heat exchanger (4) is connected to the wastewater evaporation device (5), and the desulfurization tower (2) is connected to the desulfurization wastewater pretreatment device (6). The wastewater evaporation device (5) is also connected to the desulfurization wastewater pretreatment device (6).

2. The apparatus for treating desulfurization wastewater of a thermal power plant according to claim 1, characterized in that, The heat exchanger (4) is connected to the wastewater evaporation device (5) via a hot water pipe (10) and a cold water pipe (20); An expansion tank (7) is also installed on the cold water pipe (20); A transfer pump (30) is installed on the hot water pipe (10).

3. The apparatus for treating desulfurization wastewater of a thermal power plant according to claim 1, characterized in that, The desulfurization wastewater pretreatment device (6) includes a sedimentation tank (61), a flocculation sedimentation tank (62), a first filter (63), and a clear liquid storage tank (64) connected in series. The sedimentation tank (61) is also connected in sequence to the filter press (65) and the flocculation sedimentation tank (62); The sedimentation tank (61) is connected to the desulfurization tower (2).

4. The apparatus for treating desulfurization wastewater of a thermal power plant according to claim 3, characterized in that, The wastewater evaporation device (5) includes a heating evaporator (51), a condenser (52), and a vacuum unit (53) connected in sequence. The condenser (52) is connected to the condensate storage tank (54); The heating evaporator (51) is also connected to the clear liquid storage tank (64) and the crystallization pool (55), respectively.

5. The apparatus for treating desulfurization wastewater of a thermal power plant according to claim 4, characterized in that, The heating evaporator (51) includes a heating chamber (511) and an evaporation chamber (512); The evaporation chamber (512) is positioned at a high level, and the heating chamber (511) is connected to the lower part of the evaporation chamber (512) via a circulation pump (510). The output end of the circulation pump (510) is also connected to the crystallization tank (55). The bottom of the evaporation chamber (512) is connected to the top of the heating chamber (511) via a throttle valve (100), and the top of the evaporation chamber (512) is connected in sequence to the condenser (52) and the vacuum unit (53). The top of the heating chamber (511) is connected to the evaporation chamber (512) via a balance pipe (513); The heating chamber (511) is also connected to the clear liquid storage tank (64) via the first valve (5100) and to the crystallization pool (55) via the second valve (5200).

6. The apparatus for treating desulfurization wastewater of a thermal power plant according to claim 5, characterized in that, The heating chamber (511) is equipped with a heat exchange coil (5111). The lower end of the heat exchange coil (5111) extends out of the heating chamber (511) and is connected to the hot water pipe (10), while the upper end extends out of the heating chamber (511) and is connected to the cold water pipe (20). The heating chamber (511) has an inlet (5101) at the top, which is connected to the clear liquid storage tank (64) and the crystallization tank (55) respectively. The lower part has a circulation port (5102) and is connected to the lower part of the evaporation chamber (512) through a circulation pump (510).

7. The apparatus for treating desulfurization wastewater of a thermal power plant according to claim 5, characterized in that, The lower part of the evaporation chamber (512) is provided with a spray layer (5121) connected to the circulating pump (510), and the spraying direction of the spray layer (5121) is upward spraying; The bottom of the evaporation chamber (512) is provided with a drain port (5103), which is connected to the inlet port (5101) through a throttle valve (100).

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