High-salinity wastewater concentration system and method

Abstract

The invention discloses a high-salinity wastewater concentration system and method, and belongs to the field of high-salinity wastewater treatment.The high-salinity wastewater concentration system is characterized in that a discharge port of a raw material liquid tank is communicated with a second coil heat exchanger, a discharge port of the second coil heat exchanger is communicated with a shell-and-tube heat exchanger, and a discharge port of the shell-and-tube heat exchanger is communicated with an evaporator; a material evaporation steam outlet of the evaporator is communicated with a feeding port of the gas-liquid separator, a liquid drop outlet of the gas-liquid separator is communicated with the bottom of the evaporator, a concentrated solution outlet of the evaporator is communicated with the concentrated solution buffer tank, a discharging port of the concentrated solution buffer tank is communicated with the concentrated solution storage tank, and a condensed water outlet of the evaporator is communicated with a feeding port of the condensed water tank. A discharge port of the condensate water tank is communicated with a condensate water inlet of the shell-and-tube heat exchanger, and an eighth pipeline is communicated with a heat source inlet of the first coil heat exchanger. A three-stage preheating system of non-condensable steam, concentrated liquid and condensed water is constructed, three types of core waste heat resources are comprehensively recycled, and external energy consumption of the evaporator is greatly reduced.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of high-salinity wastewater treatment, and particularly relates to a high-salinity wastewater concentration system and method. BACKGROUND

[0002] High-salinity wastewater is widely generated in industrial fields such as chemical industry, pharmaceutical industry, printing and dyeing, and coal chemical industry. It contains a large amount of soluble salts and refractory organic matter. If it is directly discharged, it will seriously pollute water bodies and soil environments, and even threaten the balance of the ecological system. Therefore, it needs to be concentrated to realize the separation of salts and the recycling of water resources, which is a key link for industrial wastewater to be discharged up to standard and resource utilization.

[0003] Evaporation concentration technology has become the mainstream technology for high-salinity wastewater treatment due to its stable operation, high concentration efficiency, and complete salt removal. The core principle of the technology is to separate salts from water by vaporizing water into steam through heating. Finally, high-concentration concentrated liquid and recyclable condensed water are obtained. However, the existing evaporation concentration system still has significant technical defects in actual application, especially in the aspect of waste heat recovery and utilization. On the one hand, the preheating design of the existing evaporation concentration system is mostly single-stage or two-stage preheating, and the preheating heat source is single, usually only using the condensed water waste heat generated by the evaporator. Other waste heat resources in the system are not fully utilized. During the operation of the evaporator, in addition to the condensed water, a large amount of non-condensable steam and high-temperature concentrated liquid are also generated. These waste heat resources are often directly discharged or only subjected to simple cooling treatment, resulting in serious waste of heat and low system thermal efficiency. On the other hand, due to the large amount of waste heat not being effectively utilized, the high-salinity wastewater to be treated has a low temperature before entering the evaporator, which needs to consume a large amount of external energy such as electricity and steam to heat it to the boiling point, resulting in high system energy consumption and a substantial increase in operating costs. At the same time, the low-temperature wastewater directly entering the high-temperature evaporator also causes a sudden change in the temperature of the evaporator pipe wall, generates thermal stress, affects the service life of the equipment, and even increases the risk of fouling, further reducing the system operation stability. SUMMARY

[0004] The present application aims to provide a high-salinity wastewater concentration system and method to overcome at least one of the above-mentioned defects in the prior art.

[0005] To achieve this purpose, the present application adopts the following technical solutions: The application provides a high-salinity wastewater concentration system, which comprises a raw material liquid tank, a first coil heat exchanger, a feeding pump, a concentrated liquid buffer tank, a second coil heat exchanger, a discharging pump, a concentrated liquid storage tank, a tube-shell heat exchanger, an evaporator, a gas-liquid separator and a condensate water tank, the first coil heat exchanger is arranged in the raw material liquid tank, the second coil heat exchanger is arranged in the concentrated liquid buffer tank, a discharge port of the raw material liquid tank is communicated with a feeding port of the second coil heat exchanger through a first pipeline, the first pipeline is provided with the feeding pump, a discharge port of the second coil heat exchanger is communicated with a feeding port of the tube-shell heat exchanger through a second pipeline, a discharge port of the tube-shell heat exchanger is communicated with a feeding port of the evaporator through a third pipeline, a material evaporation steam outlet of the evaporator is communicated with a feeding port of the gas-liquid separator through a fourth pipeline, a liquid drop outlet of the gas-liquid separator is communicated with the bottom of the evaporator through a fifth pipeline, a concentrated liquid outlet at the bottom of the evaporator is communicated with a feeding port of the concentrated liquid buffer tank through a sixth pipeline, a discharge port of the concentrated liquid buffer tank is communicated with a feeding port of the concentrated liquid storage tank through a seventh pipeline, the seventh pipeline is provided with the discharging pump, a condensate water outlet of the evaporator is communicated with a feeding port of the condensate water tank through an eighth pipeline, a discharge port of the condensate water tank is communicated with a condensate water inlet of the tube-shell heat exchanger through a ninth pipeline, and the eighth pipeline is communicated with a heat source inlet of the first coil heat exchanger through a non-condensable steam pipeline.

[0006] Preferably, the system further comprises a heating steam pipeline, a dry steam outlet of the gas-liquid separator is communicated with a heating steam inlet of the evaporator through a tenth pipeline, the tenth pipeline is provided with a compressor, a gas outlet end of the heating steam pipeline is communicated with the tenth pipeline, and the communication position is between the compressor and the heating steam inlet of the evaporator, and a gas inlet end of the heating steam pipeline is communicated with an external heating steam source.

[0007] Preferably, the system further comprises a discharge pipeline, an eleventh pipeline and a condensate water pump, a condensate water outlet of the tube-shell heat exchanger is communicated with the discharge pipeline through the eleventh pipeline, the eleventh pipeline is provided with the condensate water pump, one end of the discharge pipeline is communicated with the tenth pipeline, and the communication position is between the compressor and the dry steam outlet of the gas-liquid separator.

[0008] Preferably, the system further comprises a first liquid level instrument, a second liquid level instrument and a controller, the concentrated liquid buffer tank is provided with the first liquid level instrument, the first liquid level instrument is electrically connected with the controller, the controller is electrically connected with the discharging pump, the condensate water tank is provided with the second liquid level instrument, the second liquid level instrument is electrically connected with the controller, and the controller is electrically connected with the condensate water pump.

[0009] Preferably, the gas-liquid separator comprises a tank body, a cyclone, a baffle, a demister, a pressure sensor, and a cleaning assembly, the cyclone, the baffle, and the demister are sequentially arranged in the tank body from bottom to top, the cleaning assembly is arranged in the tank body and has two cleaning ends, the two cleaning ends are respectively located on the upper and lower sides of the demister, the tank body is provided with the pressure sensor, the pressure sensor is located below the demister, the pressure sensor is electrically connected with a controller, and the controller is electrically connected with a compressor.

[0010] Preferably, the cleaning assembly comprises a motor, a rotating shaft, a fixing ring, a cleaning turntable, a twelfth pipeline, a thirteenth pipeline, a sealing piece, and a first valve, the inner side wall of the tank body on the upper and lower sides of the demister is fixed with the fixing ring, the inner side of the fixing ring has an annular groove, one end of the twelfth pipeline is in communication with the annular groove, the other end of the twelfth pipeline is in communication with an external high-pressure water source, one end of the thirteenth pipeline is in communication with the twelfth pipeline, the other end of the thirteenth pipeline is in communication with an external high-pressure gas source, the twelfth pipeline is provided with the first valve, the top of the tank body is fixed with the motor, the bottom end of the motor is fixed with the rotating shaft, the rotating shaft is fixed with two cleaning turntables, the two cleaning turntables are respectively in rotational cooperation with the two annular grooves, the contact position of the cleaning turntable and the annular groove is provided with the sealing piece, the inside of the cleaning turntable has a plurality of cavities, each cavity is in communication with the annular groove, and the side wall of the cleaning turntable close to the demister has a plurality of cleaning hole groups, and the cleaning hole groups are in communication with the cavities.

[0011] Preferably, the plurality of cavities are equidistantly distributed along the circumference of the cleaning turntable, each cavity has a plurality of cleaning hole groups equidistantly distributed along the length direction of the cavity, the cleaning hole group comprises a vertical hole, a first inclined hole, and a second inclined hole, and the first inclined hole and the second inclined hole are respectively located on the opposite sides of the vertical hole.

[0012] Preferably, the seventh pipeline is provided with a second valve, the second valve is located between the concentrated liquid buffer tank and the discharge pump, the sixth pipeline is provided with a third valve, the ninth pipeline is provided with a fourth valve, the fourth pipeline is provided with a fifth valve, the third pipeline is provided with a sixth valve, the heating steam pipeline is provided with a seventh valve, the discharge pipeline is provided with an eighth valve and a ninth valve, the eighth valve and the ninth valve are respectively located on the left and right sides of the eleventh pipeline, the tenth pipeline is provided with a tenth valve, the tenth valve is located between the compressor and the dry steam outlet of the gas-liquid separator, the gas-liquid separator is provided with a liquid discharge pipe in communication with the cleaning liquid outlet, the liquid discharge pipe is provided with an eleventh valve, and the fifth pipeline is provided with a twelfth valve.

[0013] The application also provides a high-salinity wastewater concentration method, which is processed by using the high-salinity wastewater concentration system, and comprises the following steps: storing raw material liquid in a raw material liquid tank, performing first-stage preheating through a first coil heat exchanger, lifting to a concentrated liquid buffer tank through a feed pump, performing second-stage preheating through a second coil heat exchanger, then entering a tube-shell heat exchanger to perform third-stage preheating, and then being sent into an evaporator, the generated material evaporation steam enters a gas-liquid separator to perform gas-liquid separation, the liquid droplets are returned to the evaporator and enter the concentrated liquid storage tank together with the concentrated liquid of the evaporator to provide a heat source for the second coil heat exchanger, the concentrated liquid is finally pumped into the concentrated liquid storage tank through a discharge pump, the evaporator condensate water enters a condensate water tank, and then enters the shell side of the tube-shell heat exchanger as a heat source of the tube-shell heat exchanger, and the non-condensable steam of the evaporator enters the first coil heat exchanger to provide a heat source for the first coil heat exchanger.

[0014] Preferably, the dry steam of the gas-liquid separator is discharged or is compressed and heated by a compressor to serve as heating steam of the evaporator, and the condensate water of the tube-shell heat exchanger is discharged after heat exchange and cooling or serves as cooling water of the compressor.

[0015] The application has the following beneficial effects: 1. The first coil heat exchanger, the second coil heat exchanger and the tube-shell heat exchanger are used to build a three-stage preheating system of non-condensable steam, concentrated liquid and condensate water, three types of core waste heat resources are fully recovered, the raw material liquid is preheated to near the boiling point, the external energy consumption of the evaporator is greatly reduced, and the industrial operation cost is significantly reduced.

[0016] 2. The three-stage preheating adopts a gradient heat exchange logic of low-temperature non-condensable steam, medium-temperature concentrated liquid and high-temperature condensate water, the heat transfer temperature difference is uniform, the heat exchange efficiency loss is avoided, the raw material liquid is fed at a temperature close to the operating temperature of the evaporator, the thermal stress is eliminated, the equipment scaling and corrosion are reduced, the service life of the evaporator is prolonged, and the continuous operation stability of the system is improved.

[0017] 3. The high-integration system design is realized by internal recycling of waste heat, the condensate water can be recovered as cooling water of the compressor or discharged up to the standard, the waste heat of the non-condensable steam and the concentrated liquid is fully recovered, a closed-loop process of wastewater concentration, salt separation, waste heat recovery and water resource recycling is formed, the energy-saving and emission-reducing policy is met, and economic value and environmental benefits are achieved.

[0018] 4. The system is initially started by external heating steam to provide initial heating for the evaporator to promote the boiling point evaporation of the raw material liquid, and after stable operation, selective energy supplement can be selected according to the working condition of the output steam of the compressor, and the external heating steam serves as an emergency heat source in case of failure, thereby guaranteeing the starting efficiency and the running continuity of the system.

[0019] 5. The first liquid level instrument and the second liquid level instrument are combined with a controller to control intermittent discharge, and then the evaporation concentration multiple and the cumulative condensate water production are automatically calculated, the current condensate water production data is updated every time the discharge is performed, and high-cost and high-precision detection instruments such as a density instrument can be saved.

[0020] 6. To address the issue of demister clogging and increased pressure drop caused by materials with high organic content, this system is equipped with a cleaning component at the top. When the pressure sensor detects that the pressure drop has reached the set value, the controller controls the compressor to slow down and closes the air inlet valve, automatically starting the water washing and compressed air drying process to prevent residual liquid. At the same time, the separator achieves efficient gas-liquid separation through the synergistic effect of the hydrocyclone, baffle, and demister, and has a compact structure that saves space.

[0021] 7. During cleaning, the cleaning medium can be flexibly selected according to the degree of contamination of the demister. When there are slight droplets attached, only the high-pressure water source is turned on and sent into the annular tank through the twelfth pipe for rinsing. For scale or stubborn impurities, the high-pressure air source is turned on at the same time to form a gas-liquid two-phase flow (or separate air washing and water washing) to enhance cleaning.

[0022] 8. The motor drives the rotating shaft to rotate the two cleaning discs synchronously. The cleaning medium in the annular groove is sprayed out through the cavity of the cleaning disc and the cleaning hole group to form a dense spray beam. It sweeps along the entire circumference of the demister and combines with the upper and lower double spray to achieve a complete cleaning of the demister wire mesh.

[0023] 9. Several cavities are equidistantly distributed along the circumference of the cleaning turntable, and each cavity is equipped with cleaning hole groups equidistantly along its length, forming a circumferentially fully covered and axially high-density spray network. Combined with the multi-directional layout of vertical holes and inclined holes on both sides, as well as the cleaning hole groups on the upper and lower sides of the demister, three-dimensional cleaning of the front and sides of the wire mesh is achieved, thoroughly removing impurities inside the pores, eliminating cleaning blind spots, and ensuring consistent demister catching efficiency across the entire cross-section of the demister. Attached Figure Description

[0024] Figure 1 This is a system block diagram of the present invention (valves are not marked).

[0025] Figure 2 This is a system block diagram (valve markings) of the present invention.

[0026] Figure 3 This is a schematic diagram of the gas-liquid separator of the present invention.

[0027] Figure 4 This is a partial cross-sectional view of the gas-liquid separator of the present invention.

[0028] Figure 5 yes Figure 4 A magnified structural diagram of A in the middle.

[0029] Figure 6 This is a top view of the rotating shaft and cleaning turntable of the present invention.

[0030] Figure 7 This is a control block diagram of the present invention.

[0031] The marks in the drawings are: 1-raw material liquid tank, 2-first coil heat exchanger, 3-feeding pump, 4-concentrated liquid buffer tank, 5-second coil heat exchanger, 6-discharging pump, 7-concentrated liquid storage tank, 8-tube shell heat exchanger, 9-gas-liquid separator, 10-evaporator, 11-condensed water tank, 12-first pipeline, 13-second pipeline, 14-third pipeline, 15-fourth pipeline, 16-fifth pipeline, 17-sixth pipeline, 18-seventh pipeline, 19-eighth pipeline, 20-ninth pipeline, 21-non-condensing steam pipeline, 22-heating steam pipeline, 23-tenth pipeline, 24-compressor, 25-discharge pipeline, 26-eleventh pipeline, 27-condensed water pump, 28-first liquid level instrument, 29-second liquid level instrument, 30-controller, 91-tank body, 92-cyclone, 93-baffle, 94-antifoam device, 95-pressure sensor, 96-cleaning assembly, 961-motor, 962-rotating shaft, 963-fixing ring, 964-cleaning rotating disc, 965-twelfth pipeline, 966-thirteenth pipeline, 967-sealing element, 968-first valve, 969-annular groove, 9610-cavity, 9611-cleaning hole group, 96111-vertical hole, 96112-first inclined hole, 96113-second inclined hole, 31-second valve, 32-third valve, 33-fourth valve, 34-fifth valve, 35-sixth valve, 36-seventh valve, 37-eighth valve, 38-ninth valve, 39-tenth valve, 40-liquid discharge pipe, 41-eleventh valve, 42-twelfth valve. DETAILED DESCRIPTION

[0032] The application will be further described in conjunction with the drawings and specific embodiments.

[0033] The contents not described in detail in the specification belong to the prior art known to those skilled in the art. In the description of the application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the application. In addition, the terms "first", "second", "third" and the like are only used for differentiation and cannot be understood as indicating or implying relative importance.

[0034] As Figures 1 to 7As shown, the high-salt wastewater concentration system provided in the embodiment includes a raw material liquid tank 1, a first coil heat exchanger 2, a feed pump 3, a concentrated liquid buffer tank 4, a second coil heat exchanger 5, a discharge pump 6, a concentrated liquid storage tank 7, a tube-shell heat exchanger 8, an evaporator 10, a gas-liquid separator 9, and a condensate tank 11. The first coil heat exchanger is arranged in the raw material liquid tank 1, and the second coil heat exchanger 5 is arranged in the concentrated liquid buffer tank 4. The discharge port of the raw material liquid tank 1 is communicated with the feed port of the second coil heat exchanger 5 through a first pipeline 12, and the first pipeline 12 is provided with the feed pump 3. The discharge port of the second coil heat exchanger 5 is communicated with the feed port of the tube-shell heat exchanger 8 through a second pipeline 13. The discharge port of the tube-shell heat exchanger 8 is communicated with the feed port of the evaporator 10 through a third pipeline 14. The material evaporation steam outlet of the evaporator 10 is communicated with the feed port of the gas-liquid separator 9 through a fourth pipeline 15. The liquid drop outlet of the gas-liquid separator 9 is communicated with the bottom of the evaporator 10 through a fifth pipeline 16. The concentrated liquid outlet at the bottom of the evaporator 10 is communicated with the feed port of the concentrated liquid buffer tank 4 through a sixth pipeline 17. The discharge port of the concentrated liquid buffer tank 4 is communicated with the feed port of the concentrated liquid storage tank 7 through a seventh pipeline 18, and the seventh pipeline 18 is provided with the discharge pump 6. The condensate outlet of the evaporator 10 is communicated with the feed port of the condensate tank 11 through an eighth pipeline 19. The discharge port of the condensate tank 11 is communicated with the condensate inlet of the tube-shell heat exchanger 8 through a ninth pipeline 20. The eighth pipeline 19 is communicated with the heat source inlet of the first coil heat exchanger 2 through a non-condensed steam pipeline 21.

[0035] The embodiment also provides a high-salt wastewater concentration method, which is processed by using the high-salt wastewater concentration system described above and includes the following steps. The raw material liquid is stored in the raw material liquid tank 1, is preheated by the first coil heat exchanger 2, is lifted to the concentrated liquid buffer tank 4 by the feed pump 3, is preheated by the second coil heat exchanger 5, is preheated by the tube passage of the tube-shell heat exchanger 8, and is sent into the evaporator 10 after the three-stage preheating. The material evaporation steam generated is separated into gas and liquid in the gas-liquid separator 9, and the liquid drops are returned to the evaporator 10 and are sent into the concentrated liquid storage tank 7 together with the concentrated liquid of the evaporator 10 to provide the heat source for the second coil heat exchanger 5. The concentrated liquid is finally pumped into the concentrated liquid storage tank 7 by the discharge pump 6. The condensate of the evaporator 10 is sent into the condensate tank 11 and then is sent into the shell passage of the tube-shell heat exchanger 8 as the heat source. The non-condensed steam of the evaporator 10 is sent into the first coil heat exchanger 2 to provide the heat source for the first coil heat exchanger 2. The dry steam of the gas-liquid separator 9 is discharged or is compressed and heated by the compressor 24 to be used as the heating steam of the evaporator 10. The condensate of the tube-shell heat exchanger 8 is discharged after being cooled by heat exchange or is used as the temperature-reducing water of the compressor 24.

[0036] The application constructs a three-stage preheating system of non-condensing steam, concentrated liquid and condensed water, fully excavates three types of core waste heat resources (non-condensing steam sensible heat, high-temperature concentrated liquid sensible heat and high-temperature condensed water sensible heat) generated in the operation process of the evaporator 10, and avoids the heat waste caused by single heat source preheating. Through the step-by-step heat exchange of the first coil heat exchanger 2, the second coil heat exchanger 5 and the tube-shell heat exchanger 8, the temperature of the raw material liquid can be raised to near the boiling point before entering the evaporator 10, greatly reducing the external energy input required for heating of the evaporator 10, and compared with the existing single-stage / two-stage preheating system, the energy consumption is reduced, and the industrial operation cost is significantly reduced.

[0037] The three-stage preheating adopts a gradient heat exchange logic of low-temperature heat source, medium-temperature heat source and high-temperature heat source. The first stage uses non-condensing steam with lower temperature to realize basic insulation preheating of the raw material liquid, the second stage uses medium-temperature concentrated liquid to raise the temperature of the raw material liquid, and the third stage uses high-temperature condensed water to complete near-boiling point preheating. The heat transfer temperature difference is uniformly distributed, avoiding the loss of heat exchange efficiency caused by excessive local temperature difference. At the same time, the preheated raw material liquid enters the equipment at a temperature close to the operating temperature of the evaporator 10, eliminating the thermal stress caused by the direct impact of low-temperature fluid on high-temperature pipe wall, reducing the risk of equipment scaling and corrosion, prolonging the service life of the evaporator 10, and improving the continuous operation stability of the system.

[0038] The application realizes internal recycling of waste heat resources, without the need for additional heating devices or complex heat exchange modules, and has high system integration. The condensed water generated by the evaporator 10 can be directly discharged or recycled as the cooling water of the compressor 24 after heat recovery, realizing the recycling of water resources; the waste heat of non-condensing steam and concentrated liquid is fully recovered, reducing energy waste and environmental heat pollution caused by direct heat discharge. The whole process realizes closed-loop operation of wastewater concentration, salt separation, waste heat recovery and water resource recycling, conforms to the national energy-saving and environmental protection policy, and has economic value and environmental benefits.

[0039] The application further comprises a heating steam pipeline 22, a dry steam outlet of the gas-liquid separator 9 is communicated with a heating steam inlet of the evaporator 10 through a tenth pipeline 23, the tenth pipeline 23 is provided with a compressor 24, an air outlet end of the heating steam pipeline 22 is communicated with the tenth pipeline 23, and the communication position is between the compressor 24 and the heating steam inlet of the evaporator 10, and an air inlet end of the heating steam pipeline 22 is communicated with an external heating steam source.

[0040] At the initial stage of system startup, the raw material liquid in the evaporator 10 has not reached the boiling point, and the gas-liquid separator 9 cannot produce sufficient dry steam. The compressor 24 is difficult to start or cannot provide high-temperature heating steam to meet the demand due to the lack of gas source. At this time, the external heating steam source delivers high-temperature heating steam through the heating steam pipeline 22, which is directly introduced into the heating steam inlet of the evaporator 10 through the tenth pipeline 23, providing initial heating energy for the shell side of the evaporator 10, rapidly heating the raw material liquid in the evaporator 10 to the boiling point, and promoting the system to start the evaporation process.

[0041] When the raw material liquid reaches the boiling point and continues to evaporate, the gas-liquid separator 9 produces sufficient dry steam, which enters the compressor 24 for compression and heating to become the main flow heating steam of the evaporator 10. At this time, the external heating steam pipeline 22 can selectively supplement energy according to the system operating state. If the heating steam temperature / pressure output by the compressor 24 meets the demand of the evaporator 10, the external heating steam source can be closed, and the system relies on the cycle for self-sufficiency. If the concentration of the raw material liquid increases or the evaporation load suddenly increases, resulting in insufficient heat of the steam output by the compressor 24, the external heating steam source can be opened, and high-temperature steam is supplemented through the heating steam pipeline 22. After mixing with the steam output by the compressor 24, it is introduced into the evaporator 10 to ensure the stability of the evaporation process. If the compressor 24 fails or the gas-liquid separator 9 produces insufficient steam, the external heating steam can be used as an emergency heat source to continuously supply energy to the evaporator 10 through the heating steam pipeline 22, avoiding system downtime and affecting production continuity, and gaining time for troubleshooting and repair.

[0042] The present application solves the core problems of poor preheating recovery and high energy consumption in the prior art through the cooperative design of three-stage preheating, multi-heat source waste heat recovery, dry steam circulation, and external steam energy supplement. Through the supplement of the external heating steam pipeline 22, the technical advantages of fast startup, stable operation, and fault resistance are realized.

[0043] The system further comprises a discharge pipeline 25, an eleventh pipeline 26, and a condensate pump 27. The condensate outlet of the tube-in-shell heat exchanger 8 is connected to the discharge pipeline 25 through the eleventh pipeline 26, and the eleventh pipeline 26 is provided with the condensate pump 27. One end of the discharge pipeline 25 is connected to the tenth pipeline 23, and the connection is located between the dry steam outlet of the compressor 24 and the gas-liquid separator 9.

[0044] The condensate in the condensate tank 11 is first cooled by the tube-in-shell heat exchanger 8 and then pumped into the intake pipe of the compressor 24 by the condensate pump 27 to prevent overheating in the compressor 24. The dry steam of the gas-liquid separator 9 can be compressed and heated by the compressor 24 and then introduced into the evaporator 10, or directly discharged through the discharge pipeline 25.

[0045] The first liquid level gauge 28 is arranged on the concentrated liquid buffer tank 4, and the first liquid level gauge 28 is electrically connected with the controller 30; the controller 30 is electrically connected with the discharge pump 6; the second liquid level gauge 29 is arranged on the condensed water tank 11, and the second liquid level gauge 29 is electrically connected with the controller 30; and the controller 30 is electrically connected with the condensed water pump 27.

[0046] The first liquid level gauge 28 and the second liquid level gauge 29 are combined with the controller 30 to control intermittent discharge, so as to automatically calculate the evaporation concentration multiple and the cumulative yield of the condensed water; the current condensed water production data is updated every time the discharge is performed, and high-cost and high-precision detection instruments such as a density instrument can be saved.

[0047] The gas-liquid separator 9 comprises a tank body 91, a cyclone 92, a baffle plate 93, a demister 94, a pressure sensor 95 and a cleaning assembly 96; the cyclone 92, the baffle plate 93 and the demister 94 are sequentially arranged in the tank body 91 from bottom to top; the cleaning assembly 96 is arranged in the tank body 91 and has two cleaning ends, which are respectively located on the upper side and the lower side of the demister 94; the tank body 91 is provided with the pressure sensor 95, which is located below the demister 94; the pressure sensor 95 is electrically connected with the controller 30; and the controller 30 is electrically connected with the compressor 24.

[0048] When the material with a high content of organic matter is encountered, the steam generated by the material may carry part of the organic matter, and the demister 94 may be blocked after a long time of operation, thereby increasing the pressure drop when the steam passes through; therefore, the cleaning assembly 96 is arranged on the top; when the pressure of the pressure sensor 95 rises to a set value, the controller 30 controls the compressor 24 to slow down and stop and controls the air inlet valve to be closed; the controller 30 controls the cleaning assembly 96 to be automatically started to first pass through water washing and then to blow dry by blowing in compressed air to prevent residual liquid from being left.

[0049] The cleaning assembly 96 comprises a motor 961, a rotating shaft 962, a fixing ring 963, a cleaning rotating disc 964, a twelfth pipeline 965, a thirteenth pipeline 966, a sealing element 967 and a first valve 968. The inner side walls of the tank body 91 on the upper and lower sides of the demister 94 are fixedly connected with the fixing rings 963. The inner side of the fixing ring 963 is provided with an annular groove 969. One end of the twelfth pipeline 965 is in communication with the annular groove 969. The other end of the twelfth pipeline 965 is in communication with an external high-pressure water source. One end of the thirteenth pipeline 966 is in communication with the twelfth pipeline 965. The other end of the thirteenth pipeline 966 is in communication with an external high-pressure gas source. The twelfth pipeline 965 is provided with the first valve 968. The top of the tank body 91 is fixedly connected with the motor 961. The bottom end of the motor 961 is fixedly connected with the rotating shaft 962. The rotating shaft 962 is fixedly connected with two cleaning rotating discs 964. The two cleaning rotating discs 964 are rotatably connected with the two annular grooves 969, respectively. The contact position of the cleaning rotating disc 964 and the annular groove 969 is provided with the sealing element 967. The cleaning rotating disc 964 is internally provided with a plurality of cavities 9610. Each cavity 9610 is in communication with the annular groove 969. The side wall of the cleaning rotating disc 964, which is close to the demister 94, is provided with a plurality of cleaning hole groups 9611. The cleaning hole groups 9611 are in communication with the cavities 9610. The liquid outlet of the gas-liquid separator 9 is connected with a liquid discharge pipe 40. The liquid discharge pipe 40 is provided with an eleventh valve 41. The fifth pipeline 16 is provided with a twelfth valve 42.

[0050] During cleaning, the cleaning medium is selected according to the pollution degree of the demister 94. When only slight liquid droplets are attached, the external high-pressure water source is opened. The high-pressure water enters the annular groove 969 of the fixing ring 963 through the twelfth pipeline 965 (the first valve 968 is opened). When the scaling or stubborn impurities need to be cleaned, the high-pressure gas source is simultaneously opened. The high-pressure gas is mixed into the twelfth pipeline 965 through the thirteenth pipeline 966 to form a gas-liquid two-phase flow (or the gas washing and water washing are separately supplied).

[0051] After the motor 961 is started, the rotating shaft 962 drives the two cleaning rotating discs 964 to rotate synchronously. The high-pressure water, the high-pressure gas or the gas-liquid mixture in the annular groove 969 enters the cavities 9610 in the cleaning rotating disc 964. Then, the high-pressure water, the high-pressure gas or the gas-liquid mixture is sprayed out through the cleaning hole groups 9611 on the side of the cleaning rotating disc 964, which is close to the demister 94, to form dense spray beams. During the rotation of the cleaning rotating disc 964, the spray beams sweep along the entire cross section of the demister 94. Combined with the double spray on the upper and lower sides, the wire mesh of the demister 94 is fully covered.

[0052] The seal 967 is arranged at the contact position of the cleaning turntable 964 and the annular groove 969 to prevent high-pressure medium from leaking from the gap and ensure stable spray pressure. When the eleventh valve 41 is opened and the twelfth valve 42 is closed, the cleaned sewage enters the drain pipe 40 under the action of gravity and is discharged from the drain pipe 40. When the twelfth valve 42 is opened and the eleventh valve 41 is closed, the liquid droplets settled in the tank 91 enter the bottom of the evaporator 10 through the fifth pipeline 16.

[0053] The cleaning assembly 96 adopts a design of double turntables arranged above and below and combined with rotary spraying. The spray beams sprayed by the cleaning hole group 9611 rotate with the turntable by 360° and can cover the entire section of the demister 94, including the edges and corners, thereby completely solving the problem of the cleaning blind area of the traditional fixed nozzle. The impact force of the high-pressure water can wash away the attached liquid droplets and soft dirt, the sweeping force of the high-pressure gas can strip stubborn dirt and impurities in the pores, and the cavitation effect generated when the gas and liquid are mixed can further improve the cleaning strength, ensure the smoothness of the wire mesh pores, and maintain the mist capturing efficiency of the demister. Finally, the remaining liquid is prevented from being left by high-pressure gas blowing. The cleaning medium forms dispersed spray beams through the cleaning hole group 9611, and the pressure is uniform and concentrated, avoiding the deformation of the wire mesh caused by the direct impact of high-pressure water flow. Compared with single water washing, the gas-liquid cooperative cleaning can reduce the amount of cleaning water and reduce the scouring and wear of the wire mesh by water flow. The rotary spraying mode avoids the damage of the wire mesh caused by excessively high local pressure, significantly prolongs the service life of the demister 94, and reduces the replacement cost of the equipment. Moreover, the cleaning assembly 96 is integrated in the tank 91, and the medium conveying is realized by the rotation cooperation of the fixing ring 963 and the cleaning turntable 964, which has a compact structure and does not occupy additional space. The medium flow can be adjusted through the first valve 968, and the high-pressure water and high-pressure gas can be used alone or in combination to adapt to different pollution levels of the demister 94. Without additional complex equipment, the flexible switching of water washing, gas washing, and gas-liquid mixed washing can be realized to adapt to the diversified pollution of the demister 94 in the high-salinity wastewater concentration process.

[0054] The cavities 9610 are equidistantly distributed along the circumference of the cleaning turntable 964. Each cavity 9610 has a plurality of cleaning hole groups 9611 equidistantly distributed along the length direction of the cavity 9610. The cleaning hole group 9611 includes a vertical hole 96111, a first inclined hole 96112, and a second inclined hole 96113. The first inclined hole 96112 and the second inclined hole 96113 are respectively located on the opposite sides of the vertical hole 96111.

[0055] A plurality of cavities 9610 are distributed equidistantly along the circumference of the cleaning turntable 964, ensuring that the cleaning medium is evenly distributed on the turntable, avoiding insufficient spray intensity in local areas;Each cavity 9610 is equidistantly provided with a cleaning hole group 9611 along the length direction, further refining the spray point, so that the spray beam forms a circumferential full coverage and axial high density spray network on the cross section of the demister 94. Combined with the multi-directional layout of the vertical hole 96111, the first inclined hole 96112 and the second inclined hole 96113, the vertical hole 96111 directly sprays the screen surface, and the inclined holes on both sides spray the screen aperture side, realizing three-dimensional cleaning of the front and side of the screen, and the cleaning hole group 9611 is provided on both sides of the demister 94, completely removing the internal impurities of the screen aperture which cannot be reached by traditional single-direction spraying, eliminating the cleaning blind area from the root, and ensuring the consistent efficiency of the demister 94 full section.

[0056] The seventh pipeline 18 is provided with a second valve 31 between the concentrated liquid buffer tank 4 and the discharge pump 6, the sixth pipeline 17 is provided with a third valve 32, the ninth pipeline 20 is provided with a fourth valve 33, the fourth pipeline 15 is provided with a fifth valve 34, the third pipeline 14 is provided with a sixth valve 35, the heating steam pipeline 22 is provided with a seventh valve 36, the discharge pipeline 25 is provided with an eighth valve 37 and a ninth valve 38, the eighth valve 37 and the ninth valve 38 are respectively located on the left and right sides of the eleventh pipeline 26, and the tenth pipeline 23 is provided with a tenth valve 39 between the compressor 24 and the dry steam outlet of the gas-liquid separator 9.

[0057] All valves are around four functions of flow on-off, flow regulation, working condition switching and safety protection, and are coordinated with the controller 30, the first liquid level instrument 28, the second liquid level instrument 29, the pressure sensor 95 and the like, to realize automatic and precise control of the whole process of raw material liquid feeding, three-stage preheating, evaporation, dry steam circulation, waste heat recovery and concentrated liquid / condensed water discharge. The position design of each valve corresponds to a specific process node, and through opening degree regulation or on-off switching, the key problems of feed and load matching, preheating temperature stability, steam working condition optimization, emergency energy supplement / discharge and the like are solved.

[0058] The control mode of the application is automatically controlled by the controller 30, and the control circuit of the controller 30 can be realized by simple programming by those skilled in the art, the power supply also belongs to the common knowledge in the art, and the application is mainly used to protect mechanical devices, so the control mode and circuit connection of the application will not be explained in detail.

[0059] The above examples are only used to illustrate the technical solutions of the present application, and are not intended to limit the present application; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that; it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A high-salinity wastewater concentration system, characterized in that: It includes a raw material liquid tank, a first coil heat exchanger, a feed pump, a concentrate buffer tank, a second coil heat exchanger, a discharge pump, a concentrate storage tank, a shell-and-tube heat exchanger, an evaporator, a gas-liquid separator, and a condensate tank. The raw material tank is equipped with a first coil heat exchanger. The concentrate buffer tank is equipped with a second coil heat exchanger. The outlet of the raw material tank is connected to the inlet of the second coil heat exchanger through a first pipe; The first pipeline is equipped with a feed pump; The outlet of the second coil heat exchanger is connected to the inlet of the shell-and-tube heat exchanger via a second pipe; The outlet of the shell-and-tube heat exchanger is connected to the inlet of the evaporator via a third pipe; The material vapor outlet of the evaporator is connected to the feed inlet of the gas-liquid separator via a fourth pipe. The droplet outlet of the gas-liquid separator is connected to the bottom of the evaporator via a fifth pipe; The concentrated liquid outlet at the bottom of the evaporator is connected to the inlet of the concentrated liquid buffer tank through a sixth pipe, and the outlet of the concentrated liquid buffer tank is connected to the inlet of the concentrated liquid storage tank through a seventh pipe. The seventh pipe is equipped with a discharge pump. The condensate outlet of the evaporator is connected to the inlet of the condensate tank through the eighth pipe, and the outlet of the condensate tank is connected to the condensate inlet of the shell-and-tube heat exchanger through the ninth pipe. The eighth pipeline is connected to the heat source inlet of the first coil heat exchanger via a non-condensable steam pipeline.

2. The high-salinity wastewater concentration system according to claim 1, characterized in that: It also includes heated steam pipes; The dry steam outlet of the gas-liquid separator is connected to the heating steam inlet of the evaporator via a tenth pipe, and a compressor is installed in the tenth pipe. The outlet of the heating steam pipe is connected to the tenth pipe, and the connection point is located between the heating steam inlet of the compressor and the evaporator. The inlet end of the heating steam pipe is connected to an external heating steam source.

3. The high-salinity wastewater concentration system according to claim 2, characterized in that: It also includes the discharge pipe, the eleventh pipe, and the condensate pump; The condensate outlet of the shell-and-tube heat exchanger is connected to the discharge pipe through the eleventh pipe. The eleventh pipe is equipped with a condensate pump; One end of the discharge pipe is connected to the tenth pipe, and the connection point is located between the dry steam outlet of the compressor and the gas-liquid separator.

4. The high-salinity wastewater concentration system according to claim 3, characterized in that: It also includes a first level gauge, a second level gauge, and a controller; The concentrate buffer tank is equipped with a first level gauge, which is electrically connected to the controller, and the controller is electrically connected to the discharge pump. The condensate tank is equipped with a second level gauge, which is electrically connected to the controller, and the controller is electrically connected to the condensate pump.

5. The high-salinity wastewater concentration system according to claim 4, characterized in that: The gas-liquid separator includes a tank, a hydrocyclone, a baffle plate, a demister, a pressure sensor, and a cleaning assembly. The tank is equipped with a hydrocyclone, a baffle plate, and a demister, arranged from bottom to top. The cleaning assembly is disposed in the tank and has two cleaning ends, which are located on the upper and lower sides of the demister, respectively. The tank is equipped with a pressure sensor located below the demister. The pressure sensor is electrically connected to the controller, and the controller is electrically connected to the compressor.

6. The high-salinity wastewater concentration system according to claim 5, characterized in that: The cleaning assembly includes a motor, a rotating shaft, a retaining ring, a cleaning turntable, a twelfth pipe, a thirteenth pipe, a seal, and a first valve; The inner walls of the tanks on both the upper and lower sides of the demister are fixed with retaining rings. The inner side of the fixing ring has an annular groove, one end of the twelfth pipe is connected to the annular groove, and the other end of the twelfth pipe is connected to an external high-pressure water source. One end of the thirteenth pipe is connected to the twelfth pipe, and the other end of the thirteenth pipe is connected to an external high-pressure gas source. The twelfth pipeline is equipped with a first valve; A motor is fixed to the top of the tank, and a rotating shaft is fixed to the bottom of the motor. Two cleaning discs are fixed to the rotating shaft, and the two cleaning discs are respectively rotatably engaged with the two annular grooves. A sealing element is provided at the contact point between the cleaning turntable and the annular groove; The cleaning turntable has several cavities inside, and each cavity is connected to the annular groove; The cleaning turntable has a plurality of cleaning hole groups on one side wall near the demister, and the cleaning hole groups are in communication with the cavity.

7. The high-salinity wastewater concentration system according to claim 6, characterized in that: The cavities are distributed at equal intervals along the circumference of the cleaning turntable; Each cavity has a plurality of cleaning holes that are equidistantly spaced along its length. The cleaning hole group includes a vertical hole, a first inclined hole, and a second inclined hole; The first inclined hole and the second inclined hole are located on opposite sides of the vertical hole, respectively.

8. The high-salinity wastewater concentration system according to claim 6, characterized in that: The seventh pipeline is equipped with a second valve, which is located between the concentrate buffer tank and the discharge pump. The sixth pipeline is equipped with a third valve; The ninth pipeline is equipped with a fourth valve; The fourth pipeline is equipped with a fifth valve; The third pipeline is equipped with a sixth valve; The heating steam pipeline is equipped with a seventh valve; The discharge pipeline is equipped with an eighth valve and a ninth valve, which are located on the left and right sides of the eleventh pipeline, respectively. The tenth pipeline is equipped with a tenth valve, which is located between the compressor and the dry steam outlet of the gas-liquid separator. The cleaning liquid outlet of the gas-liquid separator is connected to a drain pipe, and the drain pipe is equipped with an eleventh valve. The fifth pipeline is equipped with a twelfth valve.

9. A method for concentrating high-salinity wastewater, characterized in that, The high-salinity wastewater concentration system according to any one of claims 1-8 is used for treatment, comprising the following steps: The raw material liquid is stored in the raw material liquid tank, preheated in the first coil heat exchanger, and then pumped to the concentrate buffer tank by the feed pump. It is then preheated in the second coil heat exchanger, and then preheated in the shell-and-tube heat exchanger. Finally, it is sent to the evaporator. The resulting material vapor enters the gas-liquid separator for gas-liquid separation. The liquid droplets settle back to the evaporator and enter the concentrate storage tank together with the evaporator concentrate, providing a heat source for the second coil heat exchanger. The concentrate is finally pumped into the concentrate storage tank by the discharge pump. The evaporator condensate enters the condensate tank and then enters the shell side of the shell-and-tube heat exchanger as a heat source. The non-condensable vapor from the evaporator enters the first coil heat exchanger, providing a heat source for the first coil heat exchanger.

10. The method for concentrating high-salinity wastewater according to claim 9, characterized in that: The dry steam discharged from the gas-liquid separator or compressed and heated by a compressor is used as heating steam for the evaporator. The condensate from the shell-and-tube heat exchanger is discharged after heat exchange and cooling, or used as desuperheating water for the compressor.

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