Sectional type concentration system for desulfurization wastewater and use method of sectional type concentration system

Abstract

The invention provides a desulfurization wastewater sectional type concentration system and a use method thereof. The desulfurization wastewater sectional type concentration system comprises a desulfurization wastewater pool, a high-temperature concentration device, a low-temperature concentration device and a desulfurization concentrated water pool which are communicated in sequence, a high-temperature spraying desulfurization assembly is arranged in the high-temperature concentration device, and a high-temperature wastewater circulating assembly communicated with the high-temperature spraying desulfurization assembly is arranged on the outer side of the high-temperature concentration device; an air outlet of the high-temperature concentration device is communicated with the desulfurization tower; a low-temperature spraying desulfurization assembly is arranged in the low-temperature concentration device, and a low-temperature wastewater circulating assembly communicated with the low-temperature spraying desulfurization assembly is arranged on the outer side of the low-temperature concentration device; and an air outlet of the low-temperature concentration device is communicated with the high-temperature concentration device. According to the invention, the separation tendency of scaling ions is effectively inhibited by controlling the low concentration ratio in the high-temperature concentration device and utilizing the filler to improve the mass transfer efficiency, and the risk of scaling blockage during concentration of high-concentration wastewater is fundamentally eradicated by canceling a filler carrier in the low-temperature concentration device.

Description

Technical Field

[0001] This invention relates to the field of desulfurization wastewater treatment technology, and in particular to a segmented concentration system for desulfurization wastewater and its application method. Background Technology

[0002] The wastewater from wet desulfurization processes in coal-fired power plants is complex in composition and of poor quality. It typically contains high concentrations of dissolved solids (such as calcium sulfate, sodium chloride, and magnesium chloride), various heavy metal ions (such as mercury, lead, chromium, and arsenic), and suspended solids (such as gypsum particles and fly ash). It is characterized by high hardness, high salt content, and strong corrosivity, and has become one of the key challenges and final steps in achieving "zero discharge of wastewater at the end" in coal-fired power plants.

[0003] Currently, the main treatment processes for desulfurization wastewater include traditional physicochemical treatment and deep concentration and solidification. The traditional "three-stage" process (neutralization-sedimentation-flocculation) can effectively remove some heavy metals and suspended solids, but its effectiveness in removing soluble salts such as chloride ions and sulfate ions is limited, and the effluent cannot be directly reused or discharged. To achieve wastewater reduction and zero discharge, thermal concentration technologies such as multi-effect evaporation (MED) and mechanical vapor recompression (MVC) are widely used. However, these technologies have high energy consumption, large equipment investment, and face serious scaling and corrosion problems, affecting the long-term stable operation of the system. Furthermore, although low-temperature flue gas concentration technology can utilize waste heat from flue gas, the concentrated liquid is easily highly acidic due to sulfur dioxide dissolution, causing severe corrosion of the flue and core equipment.

[0004] In recent years, concentration technology based on the principle of air evaporation has attracted attention due to its low energy consumption and simple process. This technology utilizes the characteristic that air has different saturation humidity at different temperatures, allowing high-temperature wastewater to directly contact and transfer mass with air, concentrating the salts after water evaporation. However, existing air concentration processes still have significant drawbacks: if a packing layer is used to enhance gas-liquid contact, scale-forming components in the desulfurization wastewater (such as...) , During the concentration of desulfurization wastewater, the packing material quickly becomes supersaturated and scales on its surface, leading to packing blockage, narrowing of channels, and increased system pressure drop. This forces frequent shutdowns for cleaning, making long-term, stable, and continuous industrial operation impossible. If an empty tower structure is used to directly achieve gas-liquid contact, the small gas-liquid contact area results in low mass transfer efficiency, large equipment size, increased investment costs, and significantly increased fan power consumption. Summary of the Invention

[0005] The present invention aims to at least partially solve one of the technical problems in the related art.

[0006] To achieve the above objectives, the present invention proposes a segmented concentration system for desulfurization wastewater, comprising a desulfurization wastewater pool, a high-temperature concentration device, a low-temperature concentration device, and a desulfurization concentrate pool connected in sequence. The high-temperature concentration device is equipped with a high-temperature spray desulfurization component, and a high-temperature wastewater circulation component connected to the high-temperature spray desulfurization component is provided on the outside of the high-temperature concentration device; the air outlet of the high-temperature concentration device is connected to the desulfurization tower. The low-temperature concentration device is equipped with a low-temperature spray desulfurization component, and a low-temperature wastewater circulation component connected to the low-temperature spray desulfurization component is provided on the outside of the low-temperature concentration device. The air outlet of the low-temperature concentration device is connected to the high-temperature concentration device.

[0007] This invention separates a high-temperature concentration unit and a low-temperature concentration unit. In the high-temperature concentration unit, by controlling the low concentration ratio and utilizing packing material to improve mass transfer efficiency, the tendency for scaling ions to precipitate is effectively suppressed. In the low-temperature concentration unit, by eliminating the packing material carrier, the risk of scaling and clogging during the concentration of high-concentration wastewater is fundamentally eliminated. The overall system achieves a compact equipment size and reduced initial investment while ensuring long-term, highly stable continuous operation. Furthermore, through a reverse cascade utilization process of air first at low temperatures and then at high temperatures, the low-temperature concentration unit acts as an air preheater for the high-temperature unit, maximizing the recovery and utilization of heat energy within the system and significantly reducing overall energy consumption.

[0008] Optionally, the high-temperature spray desulfurization component is provided with a high-temperature spray layer, a packing layer and a high-temperature air distribution device in sequence from top to bottom. The air inlet of the high-temperature air distribution device is connected to a first fan, and the air outlet of the low-temperature concentration device is connected to the air inlet of the first fan. The high-temperature spray layer is connected to the high-temperature wastewater circulation component.

[0009] Furthermore, the high-temperature wastewater circulation component includes a high-temperature circulation pipe disposed outside the high-temperature concentration device, the first end of the high-temperature circulation pipe being connected to the high-temperature spray layer, and the second end of the high-temperature circulation pipe being connected to the bottom wastewater storage area of ​​the high-temperature concentration device. The high-temperature circulation pipeline is provided with a high-temperature circulation pump and a high-temperature heat exchanger in sequence from the second end to the first end; the high-temperature heat exchanger is connected to a first external heat source.

[0010] Furthermore, the low-temperature spray desulfurization component is provided with a low-temperature spray layer and a low-temperature air distribution device in sequence from top to bottom; The low-temperature spray layer is connected to the low-temperature wastewater circulation component; The air inlet of the low-temperature air distribution device is connected to a second fan.

[0011] Furthermore, the low-temperature wastewater circulation component includes a low-temperature circulation pipe disposed outside the low-temperature concentration device, the first end of the low-temperature circulation pipe being connected to the low-temperature spray layer, and the second end of the low-temperature circulation pipe being connected to the bottom wastewater storage area of ​​the low-temperature concentration device. The low-temperature circulation pipeline is provided with a low-temperature circulation pump and a low-temperature heat exchanger in sequence from the second end to the first end; the low-temperature heat exchanger is connected to a second external heat source.

[0012] Furthermore, the connection structure between the desulfurization wastewater tank, the high-temperature concentration device, the low-temperature concentration device, and the desulfurization concentrate tank includes: A first conveying pipeline is installed between the desulfurization wastewater pool and the wastewater storage area at the bottom of the high-temperature concentration device, and a wastewater conveying pump is installed on the first conveying pipeline. A second conveying pipeline is provided between the wastewater storage area at the bottom of the high-temperature concentration device and the wastewater storage area at the bottom of the low-temperature concentration device, and a wastewater transfer pump is provided on the second conveying pipeline. A third conveying pipeline is installed between the wastewater storage area at the bottom of the low-temperature concentration unit and the desulfurization concentrate pool, and a wastewater discharge pump is installed on the third conveying pipeline.

[0013] The present invention also provides a method for using a staged concentration system for desulfurization wastewater, comprising the following steps: After the raw desulfurization wastewater from the desulfurization wastewater pond enters the low-density wastewater storage area at the bottom of the high-temperature concentration unit, the high-temperature concentration unit and the low-temperature concentration unit are started to concentrate the raw desulfurization wastewater once in the high-temperature concentration unit. During this process, the density of the wastewater in the low-density wastewater storage area at the bottom of the high-temperature concentration unit is monitored in real time, and the wastewater density is maintained at 1.10 ± 0.02. ; The wastewater, after initial concentration in the high-temperature thickener, is continuously pumped to the low-temperature thickener by a wastewater transfer pump. The wastewater undergoes secondary concentration in the low-temperature thickener. The wastewater density in the storage area of ​​the low-temperature thickener is monitored in real time; when the wastewater density rises to 1.22... Turn on the wastewater discharge pump when the wastewater density drops to 1.20. When this happens, stop the wastewater discharge pump.

[0014] Furthermore, the first concentration process includes: Ambient air enters the low-temperature concentration unit through the second fan. After the air comes into contact with the wastewater and exchanges heat in the low-temperature concentration unit, it is heated to 50±5℃. Then, it is drawn out by the first fan, and the preheated air in the low-temperature concentration unit enters the high-temperature concentration unit. In the high-temperature concentration unit, the desulfurization wastewater raw liquid is heated to the first predetermined temperature by the high-temperature heat exchanger. The desulfurization wastewater raw liquid is then evenly sprayed onto the packing area by the high-temperature spray layer. In the low-temperature concentration unit, the heated air is evenly distributed by the high-temperature air distribution device and passes through the packing from bottom to top. The air and the desulfurization wastewater undergo countercurrent contact for heat and mass transfer. The air in the high-temperature concentration unit is heated and humidified to 70±2℃ before being discharged into the desulfurization tower; During this process, the ambient air is heated twice, gradually increasing its saturation and humidity-holding capacity.

[0015] Furthermore, during a single concentration process, by controlling the inflow of the wastewater transfer pump, the circulation rate of the high-temperature circulating pump, and the outflow of the wastewater transfer pump in a coordinated manner, the density of the wastewater in the low-density wastewater storage area at the bottom of the high-temperature concentration unit is stably maintained at 1.10 ± 0.02. Within the range.

[0016] Furthermore, the secondary concentration process includes: The low-temperature circulating pump sends the wastewater to the low-temperature heat exchanger, which uses a second external heat source to heat the wastewater to a second predetermined temperature, and then sprays it out through the low-temperature spray layer. Ambient air is supplied by a blower and evenly distributed by a low-temperature air distribution device. The air comes from bottom to top and comes into countercurrent contact with the atomized wastewater droplets in the low-temperature concentration device for heat and mass transfer. Under the action of the first blower, the heated air is discharged from the top air outlet of the low-temperature concentration unit; the wastewater, after the moisture is carried away by the air, forms high-concentration wastewater in the bottom area of ​​the low-temperature concentration unit.

[0017] Furthermore, the first predetermined temperature is 75±1℃.

[0018] Furthermore, the second predetermined temperature is 60±1℃.

[0019] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0020] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a schematic diagram of a staged concentration system for desulfurization wastewater according to the present invention.

[0021] Explanation of reference numerals in the attached figures: 1. Desulfurization wastewater tank; 2. Wastewater transfer pump; 3. High-temperature concentration device; 4. High-temperature spray layer; 5. Packing area; 6. High-temperature air distribution device; 7. Wastewater transfer pump; 8. Low-temperature concentration device; 9. Low-temperature spray layer; 10. Low-temperature air distribution device; 11. Wastewater discharge pump; 12. Desulfurization concentrate tank; 13. Low-temperature circulation pump; 14. Low-temperature heat exchanger; 15. First external heat source; 16. High-temperature circulation pump; 17. High-temperature heat exchanger; 18. Second fan; 19. First fan; 20. Desulfurization tower; 21. Second external heat source. Detailed Implementation

[0022] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0023] This invention proposes a staged concentration system for desulfurization wastewater, as described below. Figure 1 Please provide a detailed explanation.

[0024] A segmented concentration system for desulfurization wastewater includes a desulfurization wastewater pool 1, a high-temperature concentration device 3, a low-temperature concentration device 8, and a desulfurization concentrate pool 12 connected in sequence. The high-temperature concentration device 3 is equipped with a high-temperature spray desulfurization component, and a high-temperature wastewater circulation component connected to the high-temperature spray desulfurization component is installed on the outside of the high-temperature concentration device 3; the air outlet of the high-temperature concentration device 3 is connected to the desulfurization tower 20. The low-temperature concentration unit 8 is equipped with a low-temperature spray desulfurization component, and the low-temperature wastewater circulation component connected to the low-temperature spray desulfurization component is installed on the outside of the low-temperature concentration unit 8. The air outlet of the low-temperature concentration unit 8 is connected to the high-temperature concentration unit 3.

[0025] This invention separates a high-temperature concentration unit 3 and a low-temperature concentration unit 8. In the high-temperature concentration unit 3, by controlling the low concentration ratio and utilizing packing material to improve mass transfer efficiency, the tendency for scaling ions to precipitate is effectively suppressed. In the low-temperature concentration unit 8, by eliminating the packing material carrier, the risk of scaling and clogging during the concentration of high-concentration wastewater is fundamentally eliminated. The overall system achieves a compact equipment size and reduced initial investment while ensuring long-term, highly stable continuous operation. Furthermore, by employing a reverse cascade utilization process of air first at low temperatures and then at high temperatures, the low-temperature concentration unit 8 acts as an air preheater for the high-temperature unit, maximizing the recovery and utilization of heat energy within the system and significantly reducing overall energy consumption.

[0026] In some embodiments, the high-temperature spray desulfurization component is provided with a high-temperature spray layer 4, a packing layer and a high-temperature air distribution device 6 in a top-to-bottom direction. The air inlet of the high-temperature air distribution device 6 is connected to the first fan 19, and the air outlet of the low-temperature concentration device 8 is connected to the air inlet of the first fan 19. The high-temperature spray layer 4 is connected to the high-temperature wastewater circulation component.

[0027] When wastewater is concentrated in the high-temperature concentration unit 3, the high-temperature wastewater circulation component pumps the wastewater from the low-density wastewater storage area at the bottom of the high-temperature concentration unit 3 to the high-temperature spray layer 4. The wastewater is then sprayed from top to bottom through the high-temperature spray layer 4, evenly distributed into the packing layer. The first fan 19 draws air from the low-temperature concentration unit 8 to the high-temperature air distribution device 6. Under the uniform distribution effect of the high-temperature air distribution device 6, the air comes into contact with the atomized wastewater from bottom to top, transferring heat and mass. After being heated, the air's saturated moisture content increases, creating an unsaturated state, which further absorbs the moisture evaporated during the atomization process of the wastewater in the high-temperature concentration unit 3.

[0028] In one specific embodiment, the high-temperature spray layer 4 includes multiple atomizing nozzles, which are connected by pipes. Wastewater can flow through the pipes to each atomizing nozzle, thereby allowing the atomized wastewater to come into contact with the upward-blown air.

[0029] In some embodiments, the high-temperature wastewater circulation assembly includes a high-temperature circulation pipe disposed outside the high-temperature concentration device 3, with a first end of the high-temperature circulation pipe connected to the high-temperature spray layer 4 and a second end of the high-temperature circulation pipe connected to the bottom wastewater storage area of ​​the high-temperature concentration device 3. A high-temperature circulating pipeline is provided with a high-temperature circulating pump 16 and a high-temperature heat exchanger 17 in sequence from the second end to the first end; the high-temperature heat exchanger 17 is connected to a first external heat source 15.

[0030] The high-temperature wastewater circulation component serves two purposes: firstly, the first external heat source 15 heats the low-density wastewater, ensuring that the atomized wastewater reaches a temperature sufficient to heat the air; secondly, heating the wastewater makes it easier for it to vaporize during atomization, ensuring the air's absorption of water vapor. These two aspects guarantee the concentration effect within the high-temperature concentration device 3.

[0031] In some embodiments, the first external heat source 15 is set as saturated steam or high-temperature flue gas, and the temperature of the saturated steam or high-temperature flue gas needs to be ≥95°C. In one preferred embodiment, the first external heat source 15 is saturated steam, and the temperature of the saturated steam is maintained at 110°C. The wastewater is heated to a first predetermined temperature by heating with saturated steam, and the first predetermined temperature range is set to 75±1°C.

[0032] In some embodiments, the low-temperature spray desulfurization component is provided with a low-temperature spray layer 9 and a low-temperature air distribution device 10 in a top-to-bottom direction. The low-temperature spray layer 9 is connected to the low-temperature wastewater circulation component; The air inlet of the low-temperature air distribution device 10 is connected to a second fan 18.

[0033] When the wastewater is concentrated in the low-temperature concentration device 8, the low-temperature wastewater circulation component will pump the wastewater located in the high-density wastewater storage area at the bottom of the low-temperature concentration device 8 to the high-temperature spray layer 4, and spray the atomized wastewater from top to bottom through the low-temperature spray layer 9; since there is no packing layer in the low-temperature concentration device 8, the scaling carrier is lost, thus eliminating the phenomenon of scaling on the surface of the packing during the high-density wastewater spraying process from the root. The second fan 18 draws ambient air into the low-temperature air distribution device 10. Under the uniform distribution effect of the low-temperature air distribution device 10, the air comes into contact with the atomized wastewater from bottom to top for heat and mass transfer. The heated air is transported to the high-temperature concentration unit 3 by the first fan 19. The low-temperature concentration unit 8 is used as the air preheater of the high-temperature concentration unit 3, which realizes the maximum recovery and utilization of heat energy in the system and reduces the energy waste of the overall system.

[0034] In one specific embodiment, the low-temperature spray layer 9 includes a plurality of atomizing nozzles, which are connected by a pipe. Wastewater can flow through the pipe to each atomizing nozzle, and each atomizing nozzle sprays downward, so that the atomized wastewater comes into contact with the upward-blown air.

[0035] In some embodiments, the low-temperature wastewater circulation assembly includes a low-temperature circulation pipe disposed outside the low-temperature concentration device 8, with a first end of the low-temperature circulation pipe connected to the low-temperature spray layer 9 and a second end of the low-temperature circulation pipe connected to the bottom wastewater storage area of ​​the low-temperature concentration device 8. The low-temperature circulation pipeline is provided with a low-temperature circulation pump 13 and a low-temperature heat exchanger 14 in sequence from the second end to the first end; the low-temperature heat exchanger 14 is connected to a second external heat source 21.

[0036] The low-temperature wastewater circulation component serves two purposes: firstly, the high-density wastewater can be heated by the second external heat source 21, ensuring that the atomized wastewater reaches a temperature sufficient to heat the air; secondly, heating the wastewater makes it easier for it to vaporize during atomization, ensuring the air's absorption of water vapor. These two aspects guarantee the concentration effect within the low-temperature concentration device 8.

[0037] In some embodiments, the second external heat source 21 is set as saturated steam or high-temperature flue gas, the temperature of which needs to be ≥95°C. In one preferred embodiment, the first external heat source 15 is saturated steam, and the temperature of the saturated steam is maintained at 110°C. The wastewater is heated to a second predetermined temperature by heating with saturated steam, the second predetermined temperature range being set to 60±1°C.

[0038] In other embodiments, the second external heat source 21 and the first external heat source 15 are the same heat source.

[0039] In some embodiments, the connection structure between the desulfurization wastewater tank 1, the high-temperature concentration device 3, the low-temperature concentration device 8, and the desulfurization concentrate tank 12 includes: A first conveying pipeline is installed between the desulfurization wastewater pool 1 and the wastewater storage area at the bottom of the high-temperature concentration device 3, and a wastewater conveying pump 2 is installed on the first conveying pipeline. A second conveying pipeline is installed between the wastewater storage area at the bottom of the high-temperature concentration device 3 and the wastewater storage area at the bottom of the low-temperature concentration device 8. A wastewater transfer pump 7 is installed on the second conveying pipeline. A third conveying pipeline is installed between the wastewater storage area at the bottom of the low-temperature concentration unit 8 and the desulfurization concentrate pool 12, and a wastewater discharge pump 11 is installed on the third conveying pipeline.

[0040] More specifically, the low-density wastewater storage area at the bottom of the high-temperature concentration device 3 is provided with a high-temperature circulation outlet, a high-temperature discharge outlet, and a desulfurization wastewater inlet from top to bottom. The high-temperature circulation outlet is connected to the high-temperature circulation pipeline, the high-temperature discharge outlet is connected to the second conveying pipeline, and the desulfurization wastewater inlet is connected to the first conveying pipeline. The high-density wastewater storage area at the bottom of the low-temperature concentration unit 8 is provided with a high-temperature wastewater inlet, a low-temperature circulation outlet, and a concentrated water discharge outlet from top to bottom. The high-temperature wastewater inlet is connected to the second conveying pipeline, the low-temperature circulation outlet is connected to the low-temperature circulation pipeline, and the concentrated water discharge outlet is connected to the third conveying pipeline. The outlet of the desulfurization wastewater pool 1 is connected to the inlet of the wastewater transfer pump 2, and the outlet of the wastewater transfer pump 2 is connected to the desulfurization wastewater inlet at the bottom of the high-temperature concentration device 3. The high-temperature discharge outlet is connected to the inlet of the wastewater transfer pump 7, and the outlet of the wastewater transfer pump 7 is connected to the high-temperature wastewater inlet of the low-temperature concentration device 8.

[0041] The present invention also provides a method for using a staged concentration system for desulfurization wastewater, comprising the following steps: After the raw desulfurization wastewater from desulfurization wastewater tank 1 enters the low-density wastewater storage area at the bottom of the high-temperature concentration device 3, the high-temperature concentration device 3 and the low-temperature concentration device 8 are started, causing the raw desulfurization wastewater to undergo one concentration in the high-temperature concentration device 3. During this process, the density of the wastewater in the low-density wastewater storage area at the bottom of the high-temperature concentration device 3 is monitored in real time, and the wastewater density is maintained at 1.10 ± 0.02. ; The wastewater, after initial concentration in the high-temperature concentration unit 3, is continuously transported to the low-temperature concentration unit 8 by the wastewater transfer pump 7. The wastewater undergoes secondary concentration in the low-temperature concentration unit 8. The wastewater density in the wastewater storage area of ​​the low-temperature concentration unit 8 is monitored in real time. When the wastewater density rises to 1.22... Wastewater discharge pump 11 is turned on when the wastewater density drops to 1.20. At that time, stop wastewater discharge pump 11.

[0042] In some embodiments, a concentration process includes: Ambient air enters the low-temperature concentration unit 8 through the second fan 18. After the air comes into contact with the wastewater and exchanges heat in the low-temperature concentration unit 8, it is heated to 50±5℃. After being drawn out by the first fan 19, the preheated air in the low-temperature concentration unit 8 enters the high-temperature concentration unit 3. After the desulfurization wastewater raw liquid in the high temperature concentration device 3 is heated to the first predetermined temperature by the high temperature heat exchanger 17, the desulfurization wastewater raw liquid is evenly sprayed to the packing area 5 by the high temperature spray layer 4; the air heated in the low temperature concentration device 8 is evenly distributed by the high temperature air distribution device 6 and passes through the packing from bottom to top, and the air and desulfurization wastewater are in countercurrent contact for heat and mass transfer. The air in the high-temperature concentration unit 3 is heated and humidified to 70±2℃ before being discharged into the desulfurization tower 20; During this process, the ambient air is heated twice, gradually increasing its saturation and humidity-holding capacity.

[0043] Specifically, the first external heat source 15 is saturated steam (110°C), and the wastewater is heated to a first predetermined temperature in the high-temperature heat exchanger 17 using saturated steam.

[0044] In some embodiments, the first predetermined temperature is 75±1℃.

[0045] In some embodiments, during a single concentration process, the inflow rate of the wastewater transfer pump 2, the circulation rate of the high-temperature circulating pump 16, and the outflow rate of the wastewater transfer pump 7 are controlled in a coordinated manner to maintain the density of the wastewater in the low-density wastewater storage area at the bottom of the high-temperature concentration device 3 stably at 1.10 ± 0.02. Within the range.

[0046] Low-rate concentration combined with a high-temperature condition of 75℃ ensures that the concentration of scale-causing ions in the wastewater is far below their saturation precipitation limit at the operating temperature, effectively inhibiting the precipitation of scale-causing ions on the packing surface from both thermodynamic and kinetic perspectives. In some embodiments, the secondary concentration process includes: The low-temperature circulating pump 13 sends the wastewater to the low-temperature heat exchanger 14, and uses the second external heat source 21 to heat the wastewater to the second predetermined temperature, and then sprays it out through the low-temperature spray layer 9. Ambient air is supplied by a blower and evenly distributed by a low-temperature air distribution device 10. The air then flows from bottom to top and comes into countercurrent contact with the atomized wastewater droplets in a low-temperature concentration device 8 for heat and mass transfer. Under the action of the first fan 19, the heated air is discharged from the top air outlet of the low temperature concentration device 8; the wastewater after the moisture is carried away by the air forms high-concentration wastewater in the bottom area of ​​the low temperature concentration device 8.

[0047] Because the low-temperature concentration unit 8 is an empty tower structure without any filler, although the mass transfer area is relatively small, it completely avoids scaling carriers and ensures the safe and stable operation of the high-concentration wastewater concentration process.

[0048] In some embodiments, the second predetermined temperature is 60±1℃.

[0049] Throughout the system, the air flow achieves tiered heating and efficient utilization: Ambient air is first supplied to the low-temperature concentration unit 8 by the second fan 18, where it is heated to 50±5℃ upon contact with wastewater, simultaneously increasing its saturated moisture content and absorbing moisture evaporated from the wastewater. Subsequently, the heated and humidified air is entirely introduced into the high-temperature concentration unit 3 as an air source via the first fan 19, where it again contacts the even hotter desulfurization wastewater (75±1℃), further heating the air and increasing its saturated moisture content, allowing it to continue absorbing moisture. Through the tiered temperature settings of the high-temperature concentration unit 3 and the low-temperature concentration unit 8, tiered heating of the air and efficient recovery of waste heat are achieved, significantly reducing the system's total energy consumption. Finally, the high-temperature, high-humidity air (70±2℃) discharged from the top of the high-temperature concentration unit 3 is introduced into the desulfurization tower 20, where its moisture and heat content enter the main desulfurization system, eliminating the need for additional treatment facilities.

[0050] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0051] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0052] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0053] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0054] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0055] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A desulfurization wastewater segmented concentration system, characterized in that, The high-temperature concentration device is internally provided with a high-temperature spray desulfurization assembly, and the outside of the high-temperature concentration device is provided with a high-temperature waste water circulating assembly in communication with the high-temperature spray desulfurization assembly; the air outlet of the high-temperature concentration device is in communication with the desulfurization tower; The low-temperature concentration device is internally provided with a low-temperature spray desulfurization assembly, and the outside of the low-temperature concentration device is provided with a low-temperature waste water circulating assembly in communication with the low-temperature spray desulfurization assembly; The air outlet of the low-temperature concentration device is in communication with the high-temperature concentration device. The high-temperature spray desulfurization assembly is sequentially provided with a high-temperature spray layer, a filler layer and a high-temperature air uniformizing device from top to bottom; 2. A desulfurization wastewater segmented concentration system according to claim 1, characterized in that, The air outlet of the low-temperature concentration device is in communication with the high-temperature concentration device. The high-temperature spray layer is in communication with the high-temperature waste water circulating assembly. The high-temperature waste water circulating assembly comprises a high-temperature circulating pipeline arranged outside the high-temperature concentration device, a first end of the high-temperature circulating pipeline is in communication with the high-temperature spray layer, and a second end of the high-temperature circulating pipeline is in communication with a bottom waste water storage area of the high-temperature concentration device; 3. A desulfurization wastewater staged concentration system as claimed in claim 2, wherein, The high-temperature circulating pipeline is sequentially provided with a high-temperature circulating pump and a high-temperature heat exchanger from the second end to the first end; and the high-temperature heat exchanger is connected with a first external heat source. The low-temperature spray desulfurization assembly is sequentially provided with a low-temperature spray layer and a low-temperature air uniformizing device from top to bottom; 4. A desulfurization wastewater staged concentration system as claimed in claim 1, wherein, The low-temperature spray layer is in communication with the low-temperature waste water circulating assembly. The air outlet of the low-temperature concentration device is in communication with the high-temperature concentration device. The low-temperature waste water circulating assembly comprises a low-temperature circulating pipeline arranged outside the low-temperature concentration device, a first end of the low-temperature circulating pipeline is in communication with the low-temperature spray layer, and a second end of the low-temperature circulating pipeline is in communication with a bottom waste water storage area of the low-temperature concentration device; 5. A desulfurization wastewater staged concentration system as claimed in claim 4, wherein, The low-temperature circulating pipeline is sequentially provided with a low-temperature circulating pump and a low-temperature heat exchanger from the second end to the first end; and the low-temperature heat exchanger is connected with a second external heat source. The communication structure between the desulfurization waste water pool, the high-temperature concentration device, the low-temperature concentration device and the desulfurization concentrated water pool comprises:

6. A desulfurization wastewater staged concentration system as claimed in claim 1, wherein, A first conveying pipeline is arranged between the desulfurization waste water pool and the bottom waste water storage area of the high-temperature concentration device, and a waste water conveying pump is arranged on the first conveying pipeline; A second conveying pipeline is arranged between the bottom waste water storage area of the high-temperature concentration device and the bottom waste water storage area of the low-temperature concentration device, and a waste water transfer pump is arranged on the second conveying pipeline; A third conveying pipeline is arranged between the bottom waste water storage area of the low-temperature concentration device and the desulfurization concentrated water pool, and a waste water discharge pump is arranged on the third conveying pipeline. The process comprises the following steps:

7. A method of using a desulfurization wastewater staged concentration system, comprising: The first concentration process comprises: After the desulfurization wastewater raw solution in the desulfurization wastewater pool enters the low-density wastewater storage area at the bottom of the high-temperature concentration device, the high-temperature concentration device and the low-temperature concentration device are started, and the desulfurization wastewater raw solution is concentrated in the high-temperature concentration device; the density of the wastewater in the low-density wastewater storage area at the bottom of the high-temperature concentration device is monitored in real time during the process, and the wastewater density is maintained at 1.10±0.02 ; The wastewater preliminarily concentrated by the high-temperature concentration device is continuously transported to the low-temperature concentration device by the wastewater transfer pump, and the wastewater after one concentration is subjected to secondary concentration in the low-temperature concentration device; the density of the wastewater in the wastewater storage area in the low-temperature concentration device is monitored in real time, and when the density of the wastewater rises to 1.22 , the wastewater discharge pump is started. When the wastewater density drops to 1.20 the wastewater discharge pump is stopped.

8. A method of using a desulfurization wastewater staged concentration system as defined in claim 7, wherein, The ambient air enters the low-temperature concentration device through the second air fan, is heated to 50±5 DEG C after being in contact with the waste water in the low-temperature concentration device and being exchanged with the waste water, and is separated through the first air fan, so that the preheated air in the low-temperature concentration device enters the high-temperature concentration device; ​ The desulfurization wastewater original solution in the high-temperature concentration device is heated to a first predetermined temperature by a high-temperature heat exchanger, and then the desulfurization wastewater original solution is uniformly sprayed to a filler area by a high-temperature spraying layer; the air heated in the low-temperature concentration device is uniformly distributed by a high-temperature air distribution device, and then passes through the filler from bottom to top, and the air and the desulfurization wastewater are countercurrently contacted to transfer heat and mass; The air in the high-temperature concentration device is heated and humidified to 70±2℃, and then discharged into the desulfurization tower; In this process, the ambient air is heated twice, and the saturated moisture capacity of the air is gradually increased.

9. A method of using a desulfurization wastewater staged concentration system as defined in claim 8, wherein, In a concentration process, the water inflow of the wastewater delivery pump, the circulating amount of the high-temperature circulating pump and the water outflow of the wastewater transfer pump are controlled in linkage, so that the density of the wastewater in the low-density wastewater storage area at the bottom of the high-temperature concentration device is stably maintained in the range of 1.10±0.02 .

10. A method of using a desulfurization wastewater staged concentration system as defined in claim 7, wherein, The secondary concentration process comprises: The low-temperature circulating pump sends the wastewater to a low-temperature heat exchanger, and uses a second external heat source to heat the wastewater to a second predetermined temperature, and then sprays the wastewater out through a low-temperature spraying layer; The ambient air is sent into by a blower, and then uniformly distributed by a low-temperature air distribution device, and then the air is countercurrently contacted to transfer heat and mass with the atomized wastewater droplets in the low-temperature concentration device from bottom to top; Under the action of the first fan, the air heated is discharged from the top air outlet of the low-temperature concentration device; and the wastewater from which the moisture is carried away forms high-concentration wastewater in the bottom area of the low-temperature concentration device.

11. A method of using a desulfurization wastewater staged concentration system as defined in claim 8, wherein, The first predetermined temperature is 75±1℃.

12. A method of using a desulfurization wastewater staged concentration system as defined in claim 10, wherein, The second predetermined temperature is 60±1℃.

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