A high-salinity wastewater treatment system for coal-fired power plants

Abstract

This invention provides a high-salinity wastewater treatment system for coal-fired power plants, relating to the field of wastewater treatment technology. The system includes a pretreatment device, a refrigeration and crystallization device, a centrifugal separation device, and a waste liquid solidification mechanism. High-salinity wastewater from the coal-fired power plant is discharged into the pretreatment device, where suspended solids are removed and the pH is neutralized. The pretreated wastewater is then pre-cooled in a refrigeration unit to lower its temperature before being discharged into the crystallization unit. The water in the wastewater freezes into ice in the crystallization unit, which floats above the non-crystallizing wastewater. The ice and wastewater are then separated by a centrifugal separation device. This invention achieves further concentration of the high-salinity wastewater through the refrigeration and crystallization devices. The concentrated liquid is then centrifuged and discharged to the waste liquid solidification mechanism for direct treatment, avoiding equipment corrosion, scaling, and salt accumulation.

Description

Technical Field

[0001] This utility model relates to the field of wastewater treatment technology, and more specifically, to a high-salinity wastewater treatment system for coal-fired power plants. Background Technology

[0002] Improving water use efficiency in thermal power plants and achieving cascade utilization of water resources and "zero discharge" of wastewater have become essential paths for thermal power enterprises to achieve sustainable development.

[0003] Currently, wastewater from coal-fired power plants both domestically and internationally generally adopts a "pretreatment + concentration and volume reduction + end-of-pipe solidification" process to achieve efficient utilization and zero wastewater discharge. Among these, concentration and volume reduction includes processes such as thermal concentration and membrane concentration, with membrane concentration and multi-effect evaporation being the mainstream processes in industrial applications.

[0004] However, both membrane concentration and thermal concentration processes suffer from problems such as equipment corrosion, scaling, and salt accumulation, which are not conducive to the long-term use of coal-fired power plants. Utility Model Content

[0005] The purpose of this invention is to provide a high-salt wastewater treatment system for coal-fired power plants, which can alleviate the problems of equipment corrosion, scaling and salt accumulation in existing membrane concentration and thermal concentration processes, which are not conducive to the long-term use of coal-fired power plants.

[0006] This utility model provides a high-salt wastewater treatment system for coal-fired power plants, including: a pretreatment device, a refrigeration crystallization device, a centrifugal separation device, and a waste liquid solidification mechanism.

[0007] The pretreatment device is used to receive high-salinity wastewater. The pretreatment device performs sedimentation and pH adjustment on the high-salinity wastewater before it is discharged from the outlet. The refrigeration crystallization apparatus includes a refrigeration device and a crystallization device arranged in sequence. The refrigeration device is connected to the discharge end of the pretreatment device, and the crystallization device is connected to the refrigeration device. The centrifugal separation device is connected to the discharge end of the crystallization equipment, and the centrifugal separation device has a liquid discharge end and a solid discharge end; The waste liquid solidification mechanism is connected to the liquid discharge end.

[0008] Furthermore, the pretreatment device includes clarification equipment and acid-base adjustment equipment; The inlet of the clarification device is used to receive high-salt wastewater, the outlet of the clarification device is connected to the inlet of the acid-base adjustment device, and the outlet of the acid-base adjustment device is connected to the inlet of the refrigeration device.

[0009] Furthermore, the clarification equipment is a sedimentation tank.

[0010] Furthermore, the acid-base adjustment device includes an acid-base adjustment tank; The inlet of the acid-base adjustment tank is connected to the outlet of the clarification equipment, and the acidity or alkalinity of the effluent from the outlet of the acid-base adjustment tank is greater than or equal to 6 and less than or equal to 8.

[0011] Furthermore, the refrigeration equipment is a refrigeration unit; The discharge temperature of the refrigeration unit is less than or equal to 3°C.

[0012] Furthermore, the crystallization equipment is a crystallizer; The discharge temperature of the crystallizer is less than or equal to -5°C.

[0013] Furthermore, the rotational speed of the centrifugal separation device is greater than or equal to 10,000 rpm.

[0014] Furthermore, the waste liquid solidification mechanism includes a concentrated wastewater tank and a solidification device; The inlet of the concentrated wastewater tank is connected to the outlet of the liquid. The discharge end of the solidification device is connected to the discharge end of the concentrated wastewater tank.

[0015] Furthermore, the high-salinity wastewater treatment system for coal-fired power plants also includes an energy storage device; The energy storage device is electrically connected to the refrigeration equipment and the crystallization equipment.

[0016] The purpose of this utility model is also to provide a high-salt wastewater treatment system for coal-fired power plants, including a circulating water drain, a cooling tower, and the provided high-salt wastewater treatment system for coal-fired power plants; The high-salinity wastewater is connected to the discharge end of the pretreatment device of the high-salinity wastewater treatment system of the coal-fired power plant; The crystal discharge end of the centrifugal separator in the high-salt wastewater treatment system of the coal-fired power plant is connected to the cooling tower.

[0017] Beneficial effects: This utility model provides a high-salinity wastewater treatment system for coal-fired power plants, comprising a pretreatment device, a refrigeration crystallization device, a centrifugal separation device, and a waste liquid solidification mechanism. High-salinity wastewater generated by the coal-fired power plant is discharged into the pretreatment device, where suspended solids are removed and the pH is neutralized. The pretreated wastewater is then pre-cooled in a refrigeration unit to lower its temperature before being discharged into the crystallization unit. The water in the high-salinity wastewater is frozen into ice in the crystallization unit, which floats above the non-crystallizing wastewater. The centrifugal separation device then discharges the concentrated high-salinity wastewater into the waste liquid solidification mechanism. The resulting ice can be reused as industrial water. This utility model achieves further concentration of the high-salinity wastewater through the refrigeration and crystallization devices, and the concentrated liquid is directly treated in the waste liquid solidification mechanism, avoiding equipment corrosion, scaling, and salt accumulation. It also achieves the separation of salt from clean water in the high-salinity wastewater, reducing water resource consumption. Attached Figure Description

[0018] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of a high-salinity wastewater treatment system for a coal-fired power plant, provided as an embodiment of the present invention.

[0020] icon: 1-High salinity wastewater; 2-Clarification equipment; 3-Acid-base adjustment equipment; 4-Refrigeration equipment; 5-Crystallization equipment; 6-Centrifugal separation device; 7-Concentrated wastewater pool; 8-Solidification device; 9-Cooling tower; 10-Storage battery. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0023] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0024] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this utility model is in use. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0025] Furthermore, terms such as "horizontal" and "vertical" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0026] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0027] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings.

[0028] See Figure 1 The high-salt wastewater treatment system for coal-fired power plants provided in this embodiment includes a pretreatment device, a refrigeration crystallization device, a centrifugal separation device, and a waste liquid solidification mechanism.

[0029] The pretreatment unit is used to treat high-salinity wastewater. After sedimentation and pH adjustment, the wastewater is discharged from the outlet. The refrigeration crystallization unit includes a refrigeration unit 4 and a crystallization unit 5 arranged sequentially. The refrigeration unit 4 is connected to the outlet of the pretreatment unit, and the crystallization unit 5 is connected to the refrigeration unit 4. The centrifugal separation unit 6 is connected to the outlet of the crystallization unit 5 and has a liquid outlet and a solid outlet. The waste liquid solidification mechanism is connected to the liquid outlet.

[0030] Specifically, in this embodiment, the high-salinity wastewater generated by the coal-fired power plant is connected to the discharge end of the pretreatment device. The pretreatment device pre-treats the high-salinity wastewater to remove suspended particles, silt, large particulate impurities, etc., and reduces the hardness by using sodium hydroxide and sodium carbonate, and neutralizes the acidity and alkalinity of the high-salinity wastewater, thereby achieving the pretreatment of the high-salinity wastewater.

[0031] The pretreated high-salt wastewater is discharged into the refrigeration equipment 4 for pre-cooling to lower its temperature. Then, it is discharged into the crystallization equipment 5. The water in the high-salt wastewater is frozen into ice in the crystallization equipment 5 and floats above the high-salt wastewater that cannot be crystallized. The concentrated high-salt wastewater is discharged to the waste liquid solidification mechanism by the centrifugal separation device. The ice generated by the crystallization can be reused as industrial water.

[0032] In this embodiment, after pretreatment of the suspended solids in the high-salt wastewater, the high-salt wastewater is further concentrated by the refrigeration equipment and the crystallization equipment 5. The concentrated high-salt wastewater is then centrifuged and discharged to the waste liquid solidification mechanism for direct treatment, which avoids equipment corrosion, scaling and salt accumulation, and achieves the separation of salt in the high-salt wastewater from clean water, reducing water resource consumption.

[0033] In this embodiment, the pretreatment device includes a clarification device 2 and an acid-base adjustment device 3.

[0034] The clarification device 2 has an inlet for receiving high-salt wastewater, and its outlet is connected to the inlet of the acid-base regulating device 3. The outlet of the acid-base regulating device 3 is connected to the inlet of the refrigeration device 4.

[0035] Clarification equipment 2 can be a high-density sedimentation tank, a mechanically accelerated stirring clarification tank, or other sedimentation tanks, in order to remove suspended particles, silt, large particles and other impurities from wastewater.

[0036] After impurities are removed, the high-salt wastewater is discharged into the acid-base adjustment device 3. By adding acidic or alkaline raw materials, the acidity or alkalinity of the high-salt wastewater in the acid-base adjustment device 3 is adjusted so that the high-salt wastewater can be further treated.

[0037] Specifically, in this embodiment, the clarification device 2 is a sedimentation tank.

[0038] In this embodiment, the high-salt wastewater is settled in a sedimentation tank to separate the liquid from the suspended impurities. After separation, sodium hydroxide and sodium carbonate are added to the sedimentation tank to reduce the hardness of the high-salt wastewater.

[0039] Furthermore, in this embodiment, the acid-base adjustment device 3 includes an acid-base adjustment tank. The inlet of the acid-base adjustment tank is connected to the outlet of the clarification device 2, and the acidity or alkalinity of the effluent from the outlet of the acid-base adjustment tank is greater than or equal to 6 and less than or equal to 8.

[0040] Specifically, in this embodiment, the high-salt wastewater is discharged into an acid-base adjustment tank after sedimentation, separation, and softening. By adding sulfuric acid solution to the acid-base adjustment tank, the acidity and alkalinity of the high-salt wastewater in the tank are adjusted so that the acidity and alkalinity of the high-salt wastewater in the tank are within the range of greater than or equal to 6 and less than or equal to 8, so that the high-salt wastewater can be treated in subsequent processes.

[0041] In this embodiment, the refrigeration device 4 is a refrigeration unit. The discharge temperature of the refrigeration unit is less than or equal to 3°C.

[0042] In this embodiment, the refrigerant cools the pretreated high-salt wastewater, reducing its temperature to 0-3°C, thereby pre-cooling the high-salt wastewater and facilitating crystallization treatment of the high-salt wastewater by the crystallization equipment 5.

[0043] In this embodiment, the crystallization device 5 is a crystallizer. The discharge temperature of the crystallizer is less than or equal to -5°C.

[0044] In this embodiment, the crystallization temperature within the crystallizer is specifically approximately -5°C to -10°C. Within this temperature range, the crystallizer can crystallize clean water from high-salt wastewater to form ice blocks. Simultaneously, this temperature does not reach the freezing point of the high-concentration saline wastewater, preventing it from freezing along with the clean water. This achieves the separation of clean water from the high-salt wastewater and simultaneously further concentrates the high-salt wastewater.

[0045] After crystallization, the pretreated high-salt wastewater is separated into two parts: ice and high-salt wastewater. The ice floats above the high-salt wastewater, and the two are separated by the separation device 6.

[0046] In this embodiment, the rotational speed of the centrifugal separation device 6 is greater than or equal to 10,000 rpm.

[0047] Specifically, in this embodiment, the crystallizer is connected to the discharge end of the centrifugal separation device 6 via a delivery pump, and the centrifugal separation device 6 is specifically a centrifuge.

[0048] In this embodiment, ice and high-salinity wastewater are discharged together into a centrifuge at a speed of 10,000-15,000 rpm, which effectively separates the ice and wastewater. In the crystallization device 5, the formed ice crystals may be small or uneven in size. The high-speed centrifugal force ensures that small ice particles are forcefully thrown away from the liquid phase, effectively overcoming the adhesion between the ice and the high-salinity wastewater, greatly reducing the phenomenon of ice particles carrying concentrate or concentrate encapsulating ice particles, thereby improving the purity of the recovered ice (solid water).

[0049] During the separation process, the centrifuge's start-up and shutdown can be determined based on the water output from the centrifuge outlet. After separation, the ice blocks remain on the upper layer of the centrifuge and can be pumped back to the coal-fired power plant's water system for reuse.

[0050] In this embodiment, the waste liquid solidification mechanism includes a concentrated wastewater tank 7 and a solidification device 8. The inlet end of the concentrated wastewater tank 7 is connected to the liquid outlet end. The inlet end of the solidification device 8 is connected to the inlet end of the concentrated wastewater tank 7.

[0051] Specifically, in this embodiment, the high-salinity wastewater is pumped to the concentrated wastewater tank 7 for storage, and then discharged into the solidification device 8 to achieve solidification treatment. The solidification device 8 can be any solidification equipment capable of performing processes such as MED (low-temperature multi-effect evaporation), MVR (meticulous vapor recompression), bypass evaporation drying, and main flue evaporation drying. In this embodiment, the solidification equipment is specifically a multi-effect evaporator crystallizer, which can convert the high-salinity wastewater into solid salt residue or dry powder, achieving zero wastewater discharge.

[0052] In this embodiment, a high-salinity wastewater treatment system for a coal-fired power plant also includes an energy storage device. The energy storage device is electrically connected to the refrigeration equipment 4 and the crystallization equipment 5.

[0053] Specifically, in this embodiment, the energy storage device is a battery 10. The battery 10 in this embodiment can realize off-peak electricity energy storage, thereby reducing the energy consumption of the coal-fired power plant processing system provided in this embodiment.

[0054] It should be noted that, as an implementable approach, the high-salt wastewater treatment system for coal-fired power plants described in this embodiment can utilize a circulating water system to achieve crystallization treatment during winter in northern regions where the ambient temperature is low (-10℃ to -20℃), thereby further achieving low-energy consumption treatment.

[0055] This embodiment provides a high-salinity wastewater treatment system for a coal-fired power plant, including a high-salinity wastewater treatment system 1, a cooling tower 9, and the provided high-salinity wastewater treatment system for a coal-fired power plant.

[0056] Among them, the high-salinity wastewater 1 is connected to the discharge end of the pretreatment device of the high-salinity wastewater treatment system of the coal-fired power plant. The crystal discharge end of the centrifugal separation device 6 of the high-salinity wastewater treatment system of the coal-fired power plant is connected to the cooling tower 9.

[0057] In this embodiment, the high-salinity wastewater 1 from the coal-fired power plant is connected to the inlet of the pretreatment device of the high-salinity wastewater treatment system. The pretreatment device precipitates and adjusts the pH of the high-salinity wastewater before discharging it from the outlet. This process removes suspended particles, silt, and large impurities from the wastewater, reduces hardness using sodium hydroxide and sodium carbonate, and neutralizes the pH of the high-salinity wastewater, thus achieving pretreatment. The pretreated high-salinity wastewater is then pre-cooled in a refrigeration unit 4 to lower its temperature. Afterward, it is discharged into a crystallization unit 5, where the water in the high-salinity wastewater is frozen into ice, which floats above the non-crystallizing high-salinity wastewater. A centrifugal separator then discharges the concentrated high-salinity wastewater to a waste liquid solidification mechanism. The separated ice blocks are discharged from the crystal outlet to a cooling tower 9 for reuse, lowering the water temperature in the cooling tower 9 and thus reducing the water consumption of the circulating water system.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model 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 utility model.

Claims

1. A high-salinity wastewater treatment system for coal-fired power plants, characterized in that, include: A pretreatment device is used to receive high-salt wastewater. The pretreatment device performs sedimentation and pH adjustment on the high-salt wastewater before it is discharged from the discharge end. A refrigeration crystallization apparatus includes a refrigeration device (4) and a crystallization device (5) arranged in sequence. The refrigeration device (4) is connected to the discharge end of the pretreatment device, and the crystallization device (5) is connected to the refrigeration device (4). A centrifugal separation device (6) is connected to the discharge end of the crystallization device (5), and the centrifugal separation device (6) has a liquid discharge end and a solid discharge end; Waste liquid solidification mechanism is connected to the liquid discharge end.

2. The high-salinity wastewater treatment system for coal-fired power plants according to claim 1, characterized in that, The pretreatment device includes a clarification device (2) and an acid-base adjustment device (3); The discharge end of the clarification device (2) is used to connect to high-salt wastewater. The discharge end of the clarification device (2) is connected to the discharge end of the acid-base adjustment device (3). The discharge end of the acid-base adjustment device (3) is connected to the discharge end of the refrigeration device (4).

3. The high-salinity wastewater treatment system for coal-fired power plants according to claim 2, characterized in that, The clarification equipment (2) is a sedimentation tank.

4. A high-salinity wastewater treatment system for coal-fired power plants according to claim 2, characterized in that, The acid-base adjustment device (3) includes an acid-base adjustment tank; The inlet of the acid-base adjustment tank is connected to the outlet of the clarification device (2), and the acidity or alkalinity of the effluent from the outlet of the acid-base adjustment tank is greater than or equal to 6 and less than or equal to 8.

5. A high-salinity wastewater treatment system for coal-fired power plants according to claim 1, characterized in that, The refrigeration equipment (4) is a refrigeration machine; The discharge temperature of the refrigeration unit is less than or equal to 3°C.

6. A high-salinity wastewater treatment system for coal-fired power plants according to claim 1, characterized in that, The crystallization device (5) is a crystallizer; The discharge temperature of the crystallizer is less than or equal to -5°C.

7. A high-salinity wastewater treatment system for coal-fired power plants according to claim 1, characterized in that, The rotational speed of the centrifugal separation device (6) is greater than or equal to 10,000 rpm.

8. A high-salinity wastewater treatment system for coal-fired power plants according to claim 1, characterized in that, The waste liquid solidification mechanism includes a concentrated wastewater tank (7) and a solidification device (8); The inlet of the concentrated wastewater tank (7) is connected to the outlet of the liquid; The discharge end of the solidification device (8) is connected to the discharge end of the concentrated liquid wastewater tank (7).

9. A high-salinity wastewater treatment system for coal-fired power plants according to any one of claims 1-8, characterized in that, The high-salt wastewater treatment system for coal-fired power plants also includes an energy storage device; The energy storage device is electrically connected to the refrigeration equipment (4) and the crystallization equipment (5).

10. A high-salinity wastewater treatment system for coal-fired power plants, characterized in that, Includes a circulating water drain (1), a cooling tower (9), and a high-salinity wastewater treatment system for coal-fired power plants as described in any one of claims 1-9; The circulating water drain (1) is connected to the discharge end of the pretreatment device of the high-salt wastewater treatment system of the coal-fired power plant; The crystal discharge end of the centrifugal separator (6) of the high-salt wastewater treatment system of the coal-fired power plant is connected to the cooling tower (9).

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