Wastewater treatment device system for desulfurization slurry waste heat recovery coupled with air evaporation and concentration

Abstract

The invention provides a waste water treatment device system for desulfurization slurry waste heat recovery coupled with air evaporation and concentration. The waste water treatment device system comprises a desulfurization unit, a flash evaporation unit, an upgrading unit and an air evaporation and concentration unit which are connected in sequence. The system realizes coupling of desulfurization slurry waste heat utilization and desulfurization wastewater treatment by air evaporation and concentration, realizes treatment of wastewater by waste heat in a desulfurization island, improves the utilization efficiency of desulfurization slurry waste heat, reduces the energy consumption of desulfurization wastewater concentration treatment, and is suitable for large-scale popularization and application.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of waste heat recovery, in particular to a desulfurization slurry waste heat recovery coupled air evaporation concentration wastewater treatment device system. BACKGROUND

[0002] In the process of limestone-gypsum wet desulfurization for removing sulfur dioxide in flue gas of coal-fired power plants, a large amount of desulfurization wastewater is generated. This part of wastewater has the characteristics of high turbidity, high hardness, high heavy metal content, super-high chloride ion content, easy scaling and easy corrosion, and is difficult to treat.

[0003] At present, desulfurization wastewater "zero discharge" needs to be achieved through multi-technology coupling, usually including wastewater pretreatment technology, concentration technology and terminal treatment technology, aiming to completely eliminate wastewater discharge and recover water resources and solid salt. Among them, the concentration technology is a key link to realize the reduction of desulfurization wastewater. Through concentration reduction treatment, the amount of wastewater can be significantly reduced, which plays a role in reducing the processing capacity of the subsequent solidification section.

[0004] In the process of limestone-gypsum wet desulfurization, when the flue gas reacts with the desulfurization slurry, the waste heat of the flue gas is transferred to the desulfurization slurry through heat transfer, causing the temperature of the desulfurization slurry to rise to 50-60℃. The waste heat carried by this part of desulfurization slurry is low-grade waste heat, which has little value and has not been reasonably utilized. If it is directly discharged or cooled, it will cause waste of energy.

[0005] The existing research on desulfurization slurry waste heat utilization mainly extracts waste heat through direct heat exchange method and heat pump heat extraction method. CN114001491A discloses a desulfurization slurry waste heat recovery device based on capillary and absorption heat pump, which comprises a capillary heat exchanger and an absorption heat pump; the capillary heat exchanger comprises a shell, two blocking plates and a plurality of capillary tubes; the two blocking plates are arranged in parallel in the shell, and the two blocking plates are sealingly connected with the inner wall of the shell to form a sealed cavity between the two blocking plates. The region of the shell located in the sealed cavity is provided with a steam inlet and a steam outlet, and the steam inlet is connected with a unit steam extraction; the two ends of the plurality of capillary tubes penetrate the two blocking plates, the region of the shell located in the front end of the capillary tube is provided with a slurry inlet, and the region of the shell located in the rear end of the capillary tube is provided with a slurry outlet and a steam outlet; the steam outlet is connected with the absorption heat pump. The device improves the utilization degree of the heat of the desulfurization slurry, and realizes the deep recovery and utilization of the waste heat of the flue gas.

[0006] CN115406294A discloses a high-efficiency anti-blocking desulfurization slurry waste heat recovery device and method, which comprises a placing plate, a supporting column, a rectangular frame, a feeding mechanism and a poking mechanism. The upper end of the placing plate is provided with a rectangular frame through a plurality of supporting columns, and a water inlet hole is formed in the left side wall of the rectangular frame close to the lower side. The flow-through pipe cooperates with the poking mechanism, and a plurality of spiral flow-through pipes are adopted, which not only increases the area of desulfurization slurry and heat medium liquid heat exchange treatment, but also increases the residence time of desulfurization slurry in the heat medium liquid, thereby improving the effect of desulfurization slurry waste heat recovery.

[0007] CN213901112U discloses a water source heat pump system for desulfurization tower slurry waste heat recovery, which comprises a desulfurization tower, a flow channel type heat exchanger, a sedimentation tank, an aeration tank, a desulfurization chemical dosing tank, a water source heat pump unit, a clean water circulating pump, a desulfurization slurry circulating pump and a heat user circulating pump; the slurry overflow pipe of the desulfurization tower is connected to the desulfurization slurry inlet of the flow channel type heat exchanger, the desulfurization slurry outlet of the flow channel type heat exchanger is sequentially connected to the sedimentation tank, the aeration tank and the desulfurization chemical dosing tank, the desulfurization chemical dosing tank is connected to the slurry spraying pipe of the desulfurization tower through the desulfurization slurry circulating pump; the water source heat pump unit is connected to the flow channel type heat exchanger through the clean water circulating pump, and the water source heat pump unit is connected to the heat user water supply pipe through the heat user circulating pump; low-temperature clean water is transported into the flow channel type heat exchanger through the clean water circulating pump to exchange heat with the desulfurization slurry, the heat-absorbed clean water enters the evaporator of the water source heat pump unit to absorb heat, and then enters the condenser to condense and release heat, and is transported back to the flow channel type heat exchanger through the clean water circulating pump.

[0008] However, the current technologies use the obtained waste heat for heating or process water preheating, which is not in the same system as flue gas desulfurization, and requires the construction of corresponding pipe networks, significantly increasing the operation cost of waste heat utilization, and there is a problem of inconvenience in waste heat recovery. SUMMARY

[0009] In view of the problems in the prior art, the present application provides a desulfurization slurry waste heat recovery coupled air evaporation concentration wastewater treatment device system, which realizes the coupling of desulfurization slurry waste heat utilization and air evaporation concentration treatment of desulfurization wastewater through the flash evaporation unit, the quality improvement unit and the air evaporation concentration unit connected in sequence with the desulfurization unit, realizes the treatment of waste water with waste heat in the desulfurization island, greatly improves the waste heat utilization efficiency, reduces the energy consumption of wastewater concentration treatment, and is suitable for wide application.

[0010] To achieve this purpose, the following technical solutions are adopted in the present application:

[0011] In a first aspect, the present application provides a desulfurization slurry waste heat recovery coupled air evaporation concentration wastewater treatment device system, which comprises a desulfurization unit, a flash evaporation unit, a quality improvement unit and an air evaporation concentration unit connected in sequence.

[0012] Air evaporation concentration technology has become an important way of heat concentration of desulfurization wastewater due to its simple equipment and easy operation. The method accelerates water evaporation by directly contacting dry air with desulfurization wastewater to realize the concentration of desulfurization wastewater.

[0013] The waste water treatment device system for desulfurization slurry waste heat recovery coupled with air evaporation concentration couples the desulfurization slurry waste heat utilization and the air evaporation concentration technology, sends part of the slurry of the desulfurization unit into the flash evaporation unit, converts the waste heat carried by the slurry into low-temperature steam, then converts the low-temperature steam into high-temperature steam through the upgrading unit, and improves the waste heat utilization value; the high-temperature steam is used for heating of the desulfurization wastewater in the air evaporation concentration unit, provides a heat source for the air evaporation concentration, saves the use of external heat sources, realizes simple application of the desulfurization slurry waste heat inside the desulfurization island, reduces the energy consumption of the air evaporation concentration technology and the operation cost of the waste heat utilization device, and realizes waste water treatment by waste heat.

[0014] The flash evaporation unit not only recovers the waste heat of the desulfurization slurry, but also pre-concentrates the desulfurization slurry, so that the pre-concentrated slurry is used as raw water of the desulfurization wastewater, and the concentration ratio of the subsequent air evaporation concentration treatment of the desulfurization wastewater is reduced.

[0015] Preferably, the desulfurization unit comprises a desulfurization tower and a first circulating pump connected with the desulfurization tower.

[0016] Preferably, the first circulating pump delivers the slurry at the lower part of the desulfurization tower to the upper part through a desulfurization slurry delivery pipeline for spraying.

[0017] Preferably, the side part of the desulfurization tower is provided with a flue gas delivery pipeline, and the top part is provided with a flue gas discharge pipeline.

[0018] Preferably, the flash evaporation unit is connected with a vacuum unit and a second circulating pump respectively.

[0019] Preferably, the second circulating pump is connected with the desulfurization tower.

[0020] Preferably, a heat exchange device is arranged between the upgrading unit and the air evaporation concentration unit.

[0021] Preferably, the upgrading unit comprises any one of a heat pump, a compressor or an electric heating device to improve the waste heat utilization value recovered by the flash evaporation unit.

[0022] Preferably, the air evaporation concentration unit comprises an air evaporation concentration tower, a third circulating pump and a booster fan.

[0023] Preferably, the bottom part of the air evaporation concentration tower is provided with a concentrated water discharge pipeline, and the top part is provided with a wet gas discharge pipeline.

[0024] The desulfurization wastewater in the application is continuously circulated in the air evaporation concentration tower until the set concentration multiple is reached, and then enters the subsequent unit treatment as desulfurization concentrated water from the concentrated water discharge pipeline.

[0025] Preferably, the third circulating pump transports the desulfurization wastewater at the lower part of the air evaporation concentration tower to the upper part for spraying through the desulfurization wastewater conveying pipeline.

[0026] Preferably, the booster fan is connected with the dry gas pipeline, and the ambient air or high-temperature flue gas of the coal-fired power plant can be used as the dry gas to realize the air evaporation concentration of the desulfurization wastewater.

[0027] Preferably, the wastewater treatment device system further comprises a solid-liquid separation device, a condensed water storage device and a condensed water pump.

[0028] Preferably, the solid-liquid separation device is arranged between the second circulating pump and the air evaporation concentration tower.

[0029] In the flash evaporation unit, a small part of the pre-concentrated desulfurization slurry is used as desulfurization wastewater raw water after passing through the solid-liquid separation device, and is introduced into the air evaporation concentration device for heat concentration treatment.

[0030] Preferably, the solid-liquid separation device comprises any one of a gypsum cyclone, a vacuum belt dewatering machine or a sedimentation tank.

[0031] Preferably, the condensed water storage device is connected with the heat exchange device.

[0032] Preferably, the condensed water pump is arranged between the condensed water storage device and the desulfurization tower, and the condensed water generated after the high-temperature steam is cooled is sent into the condensed water storage device, and then is pumped into the desulfurization tower through the condensed water pump, so as to maintain the water balance of the desulfurization unit.

[0033] Preferably, the condensed water storage device is further connected with the condensed water discharge pipeline, and the condensed water is used in other water units with high water quality requirements.

[0034] In the second aspect, the application provides a wastewater treatment method of desulfurization slurry waste heat recovery coupled with air evaporation concentration, which is carried out by using the wastewater treatment device system of desulfurization slurry waste heat recovery coupled with air evaporation concentration according to the first aspect; and the wastewater treatment method comprises the following steps:

[0035] After the sulfur-containing flue gas enters the desulfurization unit to remove sulfur dioxide, the desulfurization slurry is heated, and part of the desulfurization slurry is introduced into the flash evaporation unit to generate low-temperature steam and pre-concentrated slurry; the low-temperature steam enters the quality improvement unit to become high-temperature steam and exchanges heat with the desulfurization wastewater in the air evaporation concentration unit, so as to realize the utilization of waste heat.

[0036] The wastewater treatment method of desulfurization slurry waste heat recovery coupled with air evaporation concentration described in this invention is simple to operate and reasonably designed. It uses the low-grade waste heat of desulfurization slurry for air evaporation concentration treatment of desulfurization wastewater, realizing wastewater treatment with waste heat inside the desulfurization island, providing a heat source for desulfurization wastewater treatment using air evaporation concentration technology, and reducing the energy consumption of wastewater concentration treatment.

[0037] Preferably, the sulfur-containing flue gas enters the desulfurization tower of the desulfurization unit through the flue gas conveying pipeline, and the desulfurized flue gas is sent into the chimney through the flue gas emission pipeline.

[0038] Preferably, the desulfurization slurry in the desulfurization unit is heated to 50~60°C by sulfur-containing flue gas, for example, 50°C, 52°C, 54°C, 56°C, 58°C, 59°C or 60°C, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0039] Preferably, a portion of the desulfurization slurry heated by the sulfur-containing flue gas is returned to the desulfurization tower via a first circulation pump.

[0040] Preferably, the mass of the desulfurization slurry entering the flash unit is 50 to 100 times the mass of the steam generated by the flash unit, for example, it can be 50, 60, 70, 80, 90 or 100 times, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0041] Preferably, the temperature of the low-temperature steam is 40~50℃, for example, it can be 40℃, 42℃, 45℃, 47℃ or 50℃, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0042] Preferably, the temperature of the high-temperature steam is above 60°C, for example, it can be 60°C, 62°C, 65°C, 70°C or 80°C, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0043] Preferably, a portion of the pre-concentrated slurry is returned to the desulfurization tower via a second circulation pump, while the other portion enters the air evaporation and concentration tower via a solid-liquid separation device.

[0044] Preferably, the vacuum unit maintains the flash unit under low-pressure operating conditions, with a pressure range of 7.38~12.35 kPa. For example, it can be 7.38 kPa, 7.5 kPa, 8 kPa, 9 kPa, 10 kPa or 12.35 kPa, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0045] Preferably, the high-temperature steam exchanges heat with the desulfurization wastewater at the bottom of the air evaporation and concentration tower via a heat exchange device, and the resulting condensate is stored in a condensate storage device.

[0046] Preferably, the condensate in the condensate storage device is returned to the desulfurization tower via a condensate pump.

[0047] Preferably, the heated desulfurization wastewater is sprayed into an air evaporation and concentration tower, where it comes into direct contact with the dry gas introduced into the tower, thereby concentrating the desulfurization wastewater.

[0048] Preferably, the dry gas enters the booster fan and the air evaporation and concentration tower in sequence through the dry gas pipeline, and the generated wet gas is discharged through the wet gas discharge pipeline.

[0049] Preferably, the concentrated water produced by the air evaporation and concentration tower is discharged through a concentrated water discharge pipe.

[0050] As a preferred technical solution of the present invention, the wastewater treatment method includes the following steps:

[0051] Sulfur-containing flue gas enters the desulfurization tower of the desulfurization unit through a flue gas conveying pipeline to remove sulfur dioxide. After desulfurization, the flue gas is sent into the chimney through a flue gas emission pipeline. The desulfurization slurry is heated to 50~60℃. A portion of the desulfurization slurry is diverted into the flash evaporation unit to generate low-temperature steam at 40~50℃ and pre-concentrated slurry. A portion is returned to the desulfurization tower via the first circulation pump. The mass of the desulfurization slurry entering the flash evaporation unit is 50~100 times the mass of the steam generated by the flash evaporation unit.

[0052] Part of the pre-concentrated slurry is returned to the desulfurization tower via the second circulation pump, and the other part enters the air evaporation concentration tower via the solid-liquid separation device; the vacuum unit maintains the pressure of the flash evaporation unit at 7.38~12.35 kPa;

[0053] Low-temperature steam enters the upgrading unit and is transformed into high-temperature steam at a temperature of 60°C or above. It then exchanges heat with the desulfurization wastewater at the bottom of the air evaporation and concentration tower, which is transported by the third circulation pump, to realize the utilization of waste heat. The resulting condensate is stored in the condensate storage device. The heated desulfurization wastewater is sprayed into the air evaporation and concentration tower and comes into direct contact with the dry gas introduced into the air evaporation and concentration tower to achieve the concentration of the desulfurization wastewater.

[0054] The dry gas enters the booster fan and the air evaporation concentration tower in sequence through the dry gas pipeline, and the generated wet gas is discharged through the wet gas discharge pipeline; the condensate in the condensate storage device is returned to the desulfurization tower through the condensate pump; the concentrated water generated by the air evaporation concentration tower is discharged through the concentrated water discharge pipeline.

[0055] Compared with the prior art, the present invention has at least the following beneficial effects:

[0056] (1) The flash evaporation unit in the wastewater treatment device system of desulfurization slurry waste heat recovery coupled with air evaporation concentration provided by the present invention pre-concentrates the desulfurization slurry while extracting waste heat, thereby reducing the concentration ratio of the desulfurization wastewater in subsequent thermal concentration treatment.

[0057] (2) The wastewater treatment device system of desulfurization slurry waste heat recovery coupled with air evaporation concentration provided by the present invention is set up with a flash evaporation unit, a quality improvement unit and an air evaporation concentration unit connected in sequence with the desulfurization unit. The low-grade waste heat of the desulfurization slurry is converted into high-temperature steam through the flash evaporation unit and the quality improvement unit for the concentration treatment of desulfurization wastewater. The waste heat is used to treat wastewater inside the desulfurization island, which provides a heat source for the air evaporation concentration treatment of desulfurization wastewater, reduces the energy consumption of wastewater concentration treatment, and has broad prospects for wide-scale application. Attached Figure Description

[0058] Figure 1 This is a schematic diagram of the wastewater treatment device system of desulfurization slurry waste heat recovery coupled with air evaporation and concentration in Embodiment 1 of the present invention.

[0059] In the diagram: 1-Desulfurization tower; 2-First circulating pump; 3-Flue gas conveying pipeline; 4-Flue gas emission pipeline; 5-Vacuum unit; 6-Second circulating pump; 7-Flash evaporation unit; 8-Quality upgrading unit; 9-Heat exchange device; 10-Air evaporation and concentration tower; 11-Third circulating pump; 12-Booster fan; 13-Concentrate discharge pipeline; 14-Wet gas discharge pipeline; 15-Dry gas pipeline; 16-Solid-liquid separation device; 17-Condensate storage device; 18-Condensate pump. Detailed Implementation

[0060] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0061] The present invention will now be described in further detail. However, the examples described below are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

[0062] It should be understood that in the description of this invention, the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used only for the convenience of describing the invention and for 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 the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0063] It should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "set," "connected," and "linked" 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 invention based on the specific circumstances.

[0064] Those skilled in the art should understand that the present invention necessarily includes the necessary pipelines, conventional valves and general pump equipment for achieving process integrity, but the above content is not the main inventive point of the present invention. Those skilled in the art can add layouts based on process flow and equipment structure selection, and the present invention does not make any special requirements or specific limitations in this regard.

[0065] Example 1

[0066] This embodiment provides a wastewater treatment device system that combines waste heat recovery from desulfurization slurry with air evaporation and concentration, as shown in the schematic diagram below. Figure 1 As shown.

[0067] The wastewater treatment system includes a desulfurization unit, a flash evaporation unit 7, a quality improvement unit 8, and an air evaporation and concentration unit connected in sequence.

[0068] The desulfurization unit includes a desulfurization tower 1 and a first circulation pump 2 connected to the desulfurization tower 1;

[0069] The first circulating pump 2 transports the slurry from the lower part of the desulfurization tower 1 to the upper part for spraying through the desulfurization slurry conveying pipeline;

[0070] The desulfurization tower 1 is equipped with a flue gas conveying pipe 3 on its side and a flue gas emission pipe 4 on its top.

[0071] The flash evaporation unit 7 is connected to the vacuum unit 5 and the second circulation pump 6, respectively.

[0072] The second circulating pump 6 is connected to the desulfurization tower 1.

[0073] A heat exchange device 9 is provided between the quality improvement unit 8 and the air evaporation and concentration unit;

[0074] The quality improvement unit 8 is a heat pump.

[0075] The air evaporation and concentration unit includes an air evaporation and concentration tower 10, a third circulation pump 11, and a booster fan 12;

[0076] The air evaporation and concentration tower 10 is provided with a concentrated water discharge pipe 13 at the bottom and a wet gas discharge pipe 14 at the top.

[0077] The third circulation pump 11 transports the desulfurization wastewater from the lower part of the air evaporation and concentration tower 10 to the heat exchange device 9 for heat exchange through the desulfurization wastewater conveying pipeline, and then sprays it on the upper part of the air evaporation and concentration tower 10.

[0078] The booster fan 12 is connected to the drying gas pipeline 15.

[0079] The wastewater treatment system also includes a solid-liquid separation device 16, a condensate storage device 17, and a condensate pump 18.

[0080] The solid-liquid separation device 16 is located between the second circulating pump 6 and the air evaporation and concentration tower 10;

[0081] The solid-liquid separation device 16 is a gypsum hydrocyclone;

[0082] The condensate storage device 17 is connected to the heat exchange device 9;

[0083] The condensate pump 18 is located between the condensate storage device 17 and the desulfurization tower 1.

[0084] This embodiment also provides a wastewater treatment method using desulfurization slurry waste heat recovery coupled with air evaporation and concentration. The wastewater treatment method employs the aforementioned wastewater treatment device system using desulfurization slurry waste heat recovery coupled with air evaporation and concentration. The wastewater treatment method includes the following steps:

[0085] Sulfur-containing flue gas enters the desulfurization tower 1 of the desulfurization unit through flue gas conveying pipeline 3 to remove sulfur dioxide. After desulfurization, the flue gas is sent into the chimney through flue gas emission pipeline 4. The desulfurization slurry is heated to 55°C. A portion of the desulfurization slurry is diverted into the flash evaporation unit 7 to generate low-temperature steam at 50°C and pre-concentrated slurry. The other portion of the desulfurization slurry is returned to the desulfurization tower 1 for spraying via the first circulation pump 2. The mass of the desulfurization slurry entering the flash evaporation unit is 60 times the mass of the steam generated by the flash evaporation unit.

[0086] Part of the pre-concentrated slurry is returned to the desulfurization tower 1 via the second circulation pump 6, and the other part enters the air evaporation concentration tower 10 via the solid-liquid separation device 16; the vacuum unit 5 maintains the pressure of the flash evaporation unit 7 at 12.35 kPa;

[0087] Low-temperature steam enters the upgrading unit 8 and is transformed into high-temperature steam at 65°C. It then exchanges heat with the desulfurization wastewater at the bottom of the air evaporation and concentration tower 10, which is transported by the third circulation pump 11, through the heat exchange device 9, thereby utilizing the waste heat. The resulting condensate enters the condensate storage device 17 for storage. The heated desulfurization wastewater then enters the air evaporation and concentration tower 10 for spraying, directly contacting the dry gas introduced into the air evaporation and concentration tower 10 to achieve the concentration of the desulfurization wastewater.

[0088] Steam continues to enter the air evaporation and concentration tower 10 of the air evaporation and concentration unit;

[0089] Dry gas enters the booster fan 12 and the air evaporation concentration tower 10 sequentially through the dry gas pipeline 15, and the generated wet gas is discharged through the wet gas discharge pipeline 14; the condensate in the condensate storage device 17 is returned to the desulfurization tower 1 through the condensate pump 18; the concentrated water generated by the air evaporation concentration tower 10 is discharged through the concentrated water discharge pipeline 13.

[0090] Example 2

[0091] This embodiment provides a wastewater treatment device system that combines waste heat recovery from desulfurization slurry with air evaporation and concentration. Except for the upgrading unit being a compressor and the solid-liquid separation device being a vacuum belt dewatering machine, the wastewater treatment device system is the same as that in Embodiment 1.

[0092] Example 3

[0093] This embodiment provides a wastewater treatment device system that combines waste heat recovery from desulfurization slurry with air evaporation and concentration. Except for the upgrading unit being an electric heating device and the solid-liquid separation device being a sedimentation tank, the wastewater treatment device system is the same as that in Embodiment 1.

[0094] As can be seen from Examples 1-3, the wastewater treatment device system of desulfurization slurry waste heat recovery coupled with air evaporation concentration provided by the present invention sends part of the slurry from the desulfurization unit into the flash evaporation unit, so that the waste heat carried by the slurry is converted into low-temperature steam. Then, the low-temperature steam is converted into high-temperature steam through the upgrading unit, thereby improving the utilization value of waste heat. The high-temperature steam is used to heat the desulfurization wastewater in the air evaporation concentration unit, providing a heat source for air evaporation concentration, eliminating the need for an external heat source, realizing the simple application of desulfurization slurry waste heat inside the desulfurization island, reducing the energy consumption of air evaporation concentration technology and the operating cost of waste heat utilization device, and realizing the treatment of wastewater with waste heat.

[0095] Example 4

[0096] This embodiment provides a wastewater treatment device system that combines waste heat recovery from desulfurization slurry with air evaporation and concentration. Except for the condensate storage device, which is also connected to the condensate discharge pipe, the wastewater treatment device system is the same as that in Embodiment 1.

[0097] In this embodiment, the condensate generated after the high-temperature steam from the quality improvement unit heats the desulfurization wastewater is used in other water-using units with high water quality requirements, thus achieving efficient recycling and utilization of water resources.

[0098] The applicant declares that the detailed structural features of the present invention are illustrated through the above embodiments, but the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for the components selected in the present invention, additions of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0099] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

Claims

1. A wastewater treatment system that combines waste heat recovery from desulfurization slurry with air evaporation and concentration, characterized in that, The wastewater treatment system includes a desulfurization unit, a flash evaporation unit, a quality improvement unit, and an air evaporation and concentration unit connected in sequence.

2. The wastewater treatment device system according to claim 1, characterized in that, The desulfurization unit includes a desulfurization tower and a first circulation pump connected to the desulfurization tower; Preferably, the first circulating pump transports the slurry from the lower part of the desulfurization tower to the upper part for spraying through the desulfurization slurry conveying pipeline; Preferably, the desulfurization tower is provided with a flue gas conveying pipe on its side and a flue gas emission pipe on its top.

3. The wastewater treatment device system according to claim 1 or 2, characterized in that, The flash evaporation unit is connected to the vacuum unit and the second circulation pump, respectively. Preferably, the second circulating pump is connected to the desulfurization tower.

4. The wastewater treatment device system according to any one of claims 1 to 3, characterized in that, A heat exchange device is provided between the quality improvement unit and the air evaporation and concentration unit; Preferably, the quality improvement unit includes any one of a heat pump, a compressor, or an electric heating device.

5. The wastewater treatment apparatus system according to any one of claims 1 to 4, characterized in that, The air evaporation and concentration unit includes an air evaporation and concentration tower, a third circulation pump, and a booster fan; Preferably, the air evaporation and concentration tower is provided with a concentrated water discharge pipe at the bottom and a wet gas discharge pipe at the top; Preferably, the third circulating pump transports the desulfurization wastewater from the lower part of the air evaporation and concentration tower to the heat exchange device for heat exchange via the desulfurization wastewater conveying pipeline, and then sprays it at the upper part of the air evaporation and concentration tower. Preferably, the booster fan is connected to a drying gas pipeline.

6. The wastewater treatment apparatus system according to any one of claims 1 to 5, characterized in that, The wastewater treatment system also includes a solid-liquid separation device, a condensate storage device, and a condensate pump. Preferably, the solid-liquid separation device is located between the second circulating pump and the air evaporation and concentration tower; Preferably, the solid-liquid separation device includes any one of a gypsum hydrocyclone, a vacuum belt dewatering machine, or a sedimentation tank; Preferably, the condensate storage device is connected to the heat exchange device; Preferably, the condensate storage device is also connected to a condensate discharge pipe; Preferably, the condensate pump is located between the condensate storage device and the desulfurization tower.

7. A wastewater treatment method involving waste heat recovery from desulfurization slurry coupled with air evaporation and concentration, characterized in that, The wastewater treatment method employs the wastewater treatment device system of desulfurization slurry waste heat recovery coupled with air evaporation and concentration as described in any one of claims 1 to 6; the wastewater treatment method includes the following steps: After sulfur-containing flue gas enters the desulfurization unit to remove sulfur dioxide, the desulfurization slurry is heated. A portion of the desulfurization slurry is diverted into the flash evaporation unit to generate low-temperature steam and pre-concentrated slurry. The low-temperature steam enters the upgrading unit and becomes high-temperature steam to exchange heat with the desulfurization wastewater in the air evaporation and concentration unit, thus realizing the utilization of waste heat.

8. The wastewater treatment method according to claim 7, characterized in that, In the desulfurization unit, the desulfurization slurry is heated to 50-60°C by sulfur-containing flue gas. Preferably, a portion of the desulfurization slurry heated by the sulfur-containing flue gas is returned to the desulfurization tower via a first circulation pump; Preferably, the mass of the desulfurization slurry entering the flash evaporation unit is 50 to 100 times the mass of the steam generated by the flash evaporation unit.

9. The wastewater treatment method according to claim 7 or 8, characterized in that, The temperature of the low-temperature steam is 40~50℃; Preferably, the temperature of the high-temperature steam is above 60°C; Preferably, a portion of the pre-concentrated slurry is returned to the desulfurization tower via a second circulation pump, while the other portion enters the air evaporation and concentration tower via a solid-liquid separation device.

10. The wastewater treatment method according to any one of claims 7 to 9, characterized in that, The high-temperature steam exchanges heat with the desulfurization wastewater at the bottom of the air evaporation and concentration tower via a heat exchange device, and the resulting condensate is stored in a condensate storage device. Preferably, the condensate in the condensate storage device is returned to the desulfurization tower via a condensate pump; Preferably, the dry gas enters the booster fan and the air evaporation and concentration tower in sequence through the dry gas pipeline, and the generated wet gas is discharged through the wet gas discharge pipeline.

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