Device for recovering waste heat and evaporating high-salt organic wastewater by using water source heat pump
By using a water source heat pump to recover waste heat in high-salt wastewater treatment, combined with negative pressure evaporation kettle and double-layer evaporation coil structure, the existing high-salt wastewater treatment process equipment has solved the problems of high cost and energy consumption, and achieved high efficiency , low-cost wastewater treatment effect.
Patent Information
- Application Number
- CN202421252264.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-04
- Publication Date
- 2025-02-14
- Estimated Expiration
- 2034-06-04
AI Technical Summary
The existing high-salt wastewater treatment process has problems such as high equipment cost, high energy consumption, poor stability and high operating costs. Especially when the wastewater salt content is less than 8%, the energy consumption of the MVR evaporation system increases and the equipment is not operating. Stablize.
The waste heat is recovered by a water source heat pump, and the waste heat is evaporated through a negative pressure evaporation kettle and a double-layer evaporation coil structure, combined with a heat pump system and a heat exchanger, and the existing waste water is used as a heat source to evaporate high-salt organic waste water, reducing the boiling point of the waste water to be evaporated, and improving the Energy efficiency ratio.
It has achieved efficient reduction of the boiling point of high-salt organic wastewater, significantly reduced energy consumption and operating costs, improved treatment efficiency, and achieved continuous evaporation through the alternating operation of multiple sets of evaporators.
Smart Images
Figure CN222476244U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of wastewater treatment, in particular to a device that utilizes a water source heat pump to recover waste heat and evaporate high-salt organic wastewater. Background Art
[0002] High-salt wastewater mainly comes from production wastewater from chemical industries such as refining, power generation, pharmaceuticals, coal chemical industry, electroplating, dyes, pickled product wastewater, and landfill leachate. High-salt wastewater has complex components, which not only contain organic pollutants, but also a large number of inorganic ions. Generally, its total salt content is greater than 1%. If it is discharged directly into the water body without treatment, it will not only cause serious harm to aquatic organisms, but may even threaten human health. It also has inhibitory and toxic effects on microorganisms. It is a highly difficult wastewater to treat that is commonly recognized by the wastewater treatment industry. Therefore, the treatment of high-salt wastewater has become a difficult problem at present.
[0003] At present, the "zero discharge" treatment process of high-salinity wastewater mainly includes pretreatment process, biochemical treatment process, ultrafiltration + reverse osmosis (RO), salt concentration unit, evaporation crystallization, etc. Compared with the traditional standard discharge process, "zero discharge" and evaporation crystallization are the process requirements under the new situation of high-salinity wastewater treatment. In order to achieve "zero discharge" of wastewater, a salt concentration process is usually designed before the evaporation crystallization process to reduce the amount of wastewater and reduce process energy consumption and costs.
[0004] The existing salt concentration processes mainly include membrane filtration, MVR evaporation system, heat pump low-temperature evaporation, etc. Among them, the problem of membrane filtration is that the price of imported membranes is too high, the concentration performance of domestic homogeneous ion membranes is still not high enough, the process water migration is relatively serious, and the anti-pollution ability of ion membranes is poor and the stability is not good. The MVR evaporation system has the problem of high equipment cost, and when the salt content of wastewater is less than 8%, its energy consumption will increase, and the excessive organic matter and hardness will directly affect the normal operation of the MVR evaporation system, so frequent and regular maintenance and maintenance are required, resulting in increased operating costs.
[0005] Existing heat pump low-temperature evaporation systems generally use air energy heat pumps for low-temperature evaporation, and their energy efficiency during operation is relatively low. Utility Model Content
[0006] The technical problem to be solved by the utility model is to overcome the existing defects and provide a device for evaporating high-salt organic wastewater by recycling waste heat using a water source heat pump, which can effectively solve the problems in the background technology.
[0007] In order to achieve the above-mentioned purpose, the utility model discloses a device for evaporating high-salt organic wastewater by recovering waste heat from a water source heat pump. The technical scheme adopted is that it includes a first wastewater pool, a heat pump system and an evaporating kettle. The first wastewater pool and the heat pump system are both connected to the evaporating kettle through pipelines. The utility model also includes a second wastewater pool. The first wastewater pool is connected to the feed port of the evaporating kettle through a feed pipeline. The evaporating kettle is a negative pressure kettle, which can reduce the boiling point of water under negative pressure environment. A double-layer evaporating coil is arranged inside to make the wastewater heated more evenly. A first sewage pipe is connected below. The heat pump system is a water source heat pump with high energy efficiency ratio. It has a heating pipeline and a cooling pipeline inside. The heating pipeline is connected to the evaporating coil through a circulation pipeline, and the inlet end of the cooling pipeline is connected to the second wastewater tank, using the existing wastewater to provide a heat source, which is more energy-saving. The outlet is connected to the refrigerant inlet of the rear heat exchanger through a pipeline, and the refrigerant outlet is connected back to the second wastewater tank through a pipeline; the circulation pipeline, the evaporating coil and the heating pipeline form a closed pipeline with a heat exchange medium inside; the discharge port above the evaporator is connected to the material inlet of the heat exchanger, and the material outlet of the heat exchanger is connected to the negative pressure condensation tank, and the lower end of the negative pressure condensation tank is connected to the second sewage pipe; the low-temperature fluid coming out of the heat pump is used as the cooling refrigerant, which further improves the energy-saving effect.
[0008] The pipelines connecting the equipment rooms are all equipped with control valves, and the pipelines requiring fluid conveying equipment to provide conveying power are all equipped with conveying pumps. The evaporator is equipped with a first liquid level sensor, and the four ports of the heat exchanger are all equipped with temperature sensors. A PLC controller is also included. The PLC controller is electrically connected to the control valve, the first liquid level sensor, the temperature sensor and the motor inverter, and the motor inverter is electrically connected to the conveying pump.
[0009] As a preferred technical solution of the utility model, the circulation pipeline is connected to the lower port of the evaporation coil, and a circulation pump is installed on this section of the pipeline; the upper port of the evaporation coil is connected back to the heating pipeline through the circulation pipeline. The bottom-in and top-out method can achieve better heat exchange effect.
[0010] As a preferred technical solution of the utility model, the shell side inlet and outlet of the heat exchanger are the refrigerant inlet and outlet, and adopt the bottom-in and top-out form, and the tube side inlet and outlet are the material inlet and outlet.
[0011] As a preferred technical solution of the utility model, the negative pressure condensing tank is connected to a vacuum pump, which provides a negative pressure environment for the negative pressure condensing tank and the evaporating kettle.
[0012] As a preferred technical solution of the utility model, the liquid outlet of the negative pressure condensing tank is connected to a buffer tank, the liquid outlet of the buffer tank is connected to the second sewage pipe, the second sewage pipe is provided with a second sewage pump, and the buffer tank can ensure that there is sufficient water at the front end of the second sewage pump, thereby preventing the second sewage pump from running idle. The buffer tank is equipped with a second liquid level sensor, a pressure sensor and a pressure balancing valve, and the second liquid level sensor, the pressure sensor and the pressure balancing valve are electrically connected to the PLC controller.
[0013] As a preferred technical solution of the utility model, the first sewage pipe is connected to an evaporative dryer which can further evaporate the high-concentration wastewater and dry the solute.
[0014] As a preferred technical solution of the utility model, the heat exchange medium is water or oil.
[0015] As a preferred technical solution of the utility model, at least two groups of evaporating kettles are provided and connected in parallel, so that continuous evaporation can be performed alternately.
[0016] Compared with the prior art, the beneficial effects of the utility model are as follows: the utility model uses existing wastewater as a heat source and uses a water source heat pump to evaporate high-salt organic wastewater under negative pressure conditions, which can greatly reduce the boiling point of the wastewater to be evaporated, achieves a high energy efficiency ratio and can also achieve energy-saving effects, and reuses the low-temperature wastewater leaving the heat pump unit as a cooling medium for evaporated water, which can further reduce energy consumption and operating costs.
[0017] Furthermore, by providing multiple groups of evaporating kettles, continuous evaporation can be performed alternately. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 It is a schematic diagram of the structure of the utility model.
[0019] In the figure: 1. First wastewater tank; 2. Heat pump system; 3. Evaporator; 4. Second wastewater tank; 5. Heat exchanger; 6. Negative pressure condenser; 7. Buffer tank; 8. Water tank; 9. Evaporative dryer; 10. Feed pump; 11. Circulation pump; 12. First sewage pump; 13. Second sewage pump; 14. Vacuum pump. DETAILED DESCRIPTION
[0020] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model. Example 1
[0021] like Figure 1 As shown, the utility model discloses a device for evaporating high-salt organic wastewater by recovering waste heat using a water source heat pump. The technical solution adopted is that it includes a first wastewater pool 1 and a second wastewater pool 4. The first wastewater pool 1 contains high-salt organic wastewater to be treated, and the second wastewater pool 4 contains wastewater that draws heat from the water source heat pump.
[0022] In order to achieve continuous evaporation, two evaporating kettles 3 are arranged in parallel. A feed inlet and a heat source inlet and outlet are provided on the side of the evaporating kettle 3, a discharge port is provided on the top, and a sewage outlet is provided on the bottom. In order to make the material in the evaporating kettle 3 heated more quickly and evenly, an inner and outer double-layer evaporating coil is installed in the evaporating kettle 3, and the two ports of the double-layer evaporating coil are respectively connected to the heat source inlet and outlet.
[0023] The discharge port of the first wastewater pool 1 is connected to the feed pump 10 through a pipeline, the outlet of the feed pump 10 is connected to the feed pipeline, and the feed pipeline is connected to the feed port of the evaporator 3. In order to maintain the pressure in the evaporator 3 in a normal state during the feeding process, an exhaust valve is installed on the evaporator 3. The exhaust valve is an electronic ball valve, which can maintain the pressure balance in the tank when discharging wastewater. In order to measure the temperature, pressure and material amount in the evaporator 3, a temperature sensor, a pressure sensor and a liquid level sensor are installed on the kettle body, and a PLC controller is also set. The PLC controller is electrically connected to the temperature sensor, pressure sensor, liquid level sensor, and exhaust valve. In order to adjust the output power of the pump body, the PLC controller is connected to multiple groups of motor inverters, one of which is electrically connected to the feed pump 10.
[0024] In order to increase the temperature in the evaporator 3, a heat pump system 2 is also introduced. The heat pump system 2 has a heating pipeline and a cooling pipeline. The inlet of the cooling pipeline is connected to the outlet of the second wastewater pool 4 through a pipeline. The heat source inlet and outlet of the evaporator 3 are connected to the two ends of the heating pipeline through two circulation pipelines. The circulation pipeline, the upper evaporation coil, and the heating pipeline together form a closed pipeline. Water is filled inside as a circulation medium. A circulation pump 11 is connected to the connecting pipeline between the heating pipeline and the heat source inlet of the evaporator 3 to provide circulation power for the circulation medium. The heat pump system 2 draws heat from the wastewater entering the cooling pipeline, and heats the water in the heating pipeline to about 35°C. The high-salt organic wastewater in the evaporator 3 is heated by hot water at 35°C. In order to control the entry of circulating media into the two sets of evaporators 3, proportional valves are installed at the heat source inlets of the two sets of evaporators 3. The proportional valves, the heat pump system 2 and the PLC controller are electrically connected, and the circulating pump 11 is electrically connected to a motor frequency converter connected to the PLC controller.
[0025] The other port of the cooling pipeline is connected to the shell side inlet of the rear end heat exchanger 5 through the refrigerant pipeline, and the shell side outlet of the heat exchanger 5 is connected back to the second wastewater tank 4 through the return pipeline. A delivery pump is installed on the heat pump system 2 to carry out fluid delivery operations in the cooling pipeline. The delivery pump is electrically connected to a motor inverter connected to the PLC controller.
[0026] The lower sewage outlet of the evaporator 3 is connected to the first sewage pipe, and the first sewage pipe is equipped with a first sewage pump 12; the upper discharge port of the evaporator 3 is connected to the pipe inlet of the heat exchanger 5 through the discharge pipe. In order to control the feeding, discharging and sewage discharge of the evaporator 3, a feed valve, a discharge valve and a sewage valve are respectively installed at the feeding port, the discharging port and the sewage outlet. All three are electric ball valves and are electrically connected to the PLC controller.
[0027] The discharge port above the evaporator 3 is connected to the tube side inlet of the heat exchanger 5 through the discharge pipe, and the water vapor in the tube side is condensed by the low-temperature waste water in the shell side of the heat exchanger 5. The tube side outlet of the heat exchanger 5 is connected to the inlet of the negative pressure condensation tank 6 through a pipeline. In order to control the heat exchange effect of the heat exchanger 5, temperature sensors are installed at the tube side inlet and outlet and the shell side inlet and outlet of the heat exchanger 5, and a flow sensor is installed at the shell side inlet. The temperature sensor and the flow sensor are electrically connected to the PLC controller.
[0028] The lower end of the negative pressure condensation tank 6 is connected to the buffer tank 7 and then to the second sewage pipe. The second sewage pipe is provided with a second sewage pump 13. The buffer tank 7 can prevent the second sewage pump 13 from idling. In order to form negative pressure in the negative pressure condensation tank 6 and the evaporator 3, the upper end of the negative pressure condensation tank 6 is connected to a vacuum pump 14 through a vacuum pipeline. The vacuum pump 14 adopts a water ring vacuum pump. A water tank 8 is arranged beside the vacuum pump 14 to provide a water source for the vacuum pump 14. In order to prevent the vacuum pump 14 from sucking the sewage entering the negative pressure condensation tank 6 into the negative pressure pipeline, a baffle is installed on the inner side of the inlet of the negative pressure condensation tank 6. In order to measure the liquid level in the buffer tank 7, a liquid level sensor is installed on the buffer tank 7, and electric ball valves are installed at the inlet and outlet of the buffer tank 7 respectively. In order to ensure the pressure balance in the buffer tank 7, an exhaust valve is installed on the buffer tank 7. The exhaust valve is an electronic ball valve, which can maintain the pressure balance in the tank when discharging wastewater; the second sewage pump 13 and the vacuum pump 14 are electrically connected to a motor frequency converter connected to the PLC controller.
[0029] The sewage outlet below the evaporation kettle 3 is connected to the evaporation dryer 9 through a first sewage pipe. A first sewage pump 12 is installed on the first sewage pipe. The first sewage pump 12 is electrically connected to a motor frequency converter connected to the PLC controller.
[0030] The motor frequency converter connected to the PLC controller corresponds to the feed pump 10, the circulation pump 11, the first sewage pump 12, the second sewage pump 13, the vacuum pump 14, and the delivery pump one by one, and the PLC controller is also connected to an operation panel.
[0031] The working principle of this utility model:
[0032] The control panel is operated to start the evaporation device, the PLC controller starts the heat pump system 2, the delivery pump, the circulation pump 11 and the vacuum pump 14, the discharge valve of the evaporator 3 and the inlet valve of the buffer tank 7 are opened, the delivery pump draws the wastewater in the second wastewater pool 4 into the cooling pipeline of the heat pump system 2, the circulation pump 11 drives the water circulation in the circulation pipeline, the double-layer evaporation coil and the heating pipeline, the heat pump system 2 draws heat from the wastewater in the cooling pipeline to heat the water in the heating pipeline, the hot water in the heating pipeline enters the evaporation coil through the circulation pipeline to preheat the evaporator 3 to 35°C; the vacuum pump 14 reduces the pressure in the negative pressure condensation tank 6, the heat exchanger 5 and the evaporator 3 to a relative pressure of -0.098MPa (in this embodiment, relative to the external atmospheric pressure in Henan Province), at which time the boiling point of water is 30°C, which is lower than the tank temperature of 35°C of the evaporator 3. The delivery pump delivers the low-temperature wastewater in the cooling pipeline into the heat exchanger 5 to pre-cool the heat exchanger 5. After pre-cooling, the wastewater flows back to the second wastewater tank 4.
[0033] The PLC controller starts the feed pump 10 and opens the feed valve of the first group of evaporation kettles 3 to feed the high-salt organic wastewater in the first wastewater pool 1 into the first group of evaporation kettles 3, and at the same time adjusts the opening of the proportional valve of the second group of evaporation kettles 3 to one third to maintain the preheating of the second group of evaporation kettles 3; during the feeding process of the first group of evaporation kettles 3, the PLC controller detects the pressure in the evaporation kettle 3 through the pressure sensor, and adjusts the speed of the vacuum pump 14 in real time to maintain the pressure in the tank; when the PLC controller detects that the first group of evaporation kettles 3 reaches the set feed amount through the liquid level sensor, the feed valve of the first group of evaporation kettles 3 is closed, the feed valve of the second group of evaporation kettles 3 is opened, and at the same time adjusts the opening of the proportional valve of the first group of evaporation kettles 3 to one third, and the opening of the proportional valve of the second group of evaporation kettles 3 to fully open, so as to maintain the temperature in the first group of evaporation kettles 3, and start evaporating the materials in the second group of evaporation kettles 3 while continuing the evaporation.
[0034] The water vapor discharged from the discharge port enters the heat exchanger 5 for condensation, and enters the negative pressure condensation tank 6 after condensation. The PLC controller adjusts the power of the delivery pump in real time by monitoring the outlet temperature of the heat exchanger 5, thereby reducing energy waste while ensuring the condensation effect. The condensate entering the negative pressure condensation tank 6 enters the buffer tank 7 downward. When the PLC controller detects that the liquid level in the buffer tank 7 reaches the upper limit, the inlet valve of the buffer tank 7 is closed, and the outlet valve and exhaust valve of the buffer tank 7 are opened. At this time, the subsequent condensate is buffered in the negative pressure condensation tank 6, and the pressure in the buffer tank 7 rises to the external atmospheric pressure. When the set delay time is reached, the condensate in the buffer tank 7 completes the filling of the second sewage pump 13, and then the second sewage pump 13 is opened to send the low-concentration wastewater in the buffer tank 7 into the storage tank. During this period, the external air enters the buffer tank 7 from the exhaust valve to maintain the pressure in the tank. When the PLC controller detects that the liquid level in the buffer tank 7 reaches the set lower limit, the second sewage pump 13 is stopped, the outlet valve of the buffer tank 7 is closed, and the inlet valve of the buffer tank 7 is opened to allow the condensate buffered in the negative pressure condensation tank 6 to enter the buffer tank 7, and continue to enter the liquid until the upper limit is reached again, and the cycle is repeated.
[0035] When the PLC controller detects that the liquid level in the first group of evaporating kettles 3 reaches the set sewage discharge volume, the discharge valve is closed, the sewage valve and the exhaust valve are opened, and the pressure in the first group of evaporating kettles 3 rises to the external atmospheric pressure. After the high-concentration waste liquid completes the filling of the first sewage pump 12 after the delay setting time, the first sewage pump 12 is opened to discharge the remaining high-concentration waste liquid in the first group of evaporating kettles 3 and send it to the evaporative dryer 9 for further evaporation and drying. During this period, the external air enters the first group of evaporating kettles 3 to balance the air pressure; when it is detected that the liquid level in the first group of evaporating kettles 3 reaches the lower limit, the sewage valve is closed, and the second evaporating kettle 3 is fed at this time. The feed valve of the second evaporating kettle 3 is closed, and the discharge valve and feed valve of the first evaporating kettle 3 are opened to maintain the negative pressure condition in the first group of evaporating kettles 3 while continuing the second batch of evaporation operations. In this way, the two groups of evaporating kettles 3 complete alternating operations and achieve continuous evaporation.
[0036] The circuits and mechanical connections involved in the present utility model are conventional means used by those skilled in the art, and technical inspiration can be obtained through a limited number of experiments, which belong to common knowledge.
[0037] Components not described in detail herein are prior art.
[0038] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.
Claims
1. A device for evaporating high-salt organic wastewater by recovering waste heat from a water source heat pump, comprising a first wastewater pool (1), a heat pump system (2) and an evaporation kettle (3), wherein the first wastewater pool (1) and the heat pump system (2) are connected to the evaporation kettle (3) via a pipeline, and characterized in that: The heat pump system (2) further comprises a second wastewater pool (4), wherein the first wastewater pool (1) is connected to the feed port of the evaporator (3) via a feed pipe, the evaporator (3) is a negative pressure kettle, a double-layer evaporation coil is arranged inside, and a first sewage pipe is connected at the bottom; the heat pump system (2) is a water source heat pump, and a heating pipeline and a cooling pipeline are arranged inside the heating pipeline, the heating pipeline is connected to the evaporation coil via a circulation pipeline, the cooling pipeline inlet end is connected to the second wastewater pool (4), the outlet is connected to the refrigerant inlet of the rear heat exchanger (5) via a pipeline, and the refrigerant outlet is connected back to the second wastewater pool (4) via a pipeline; the circulation pipeline, the evaporation coil, and the heating pipeline form a closed pipeline, and a heat exchange medium is arranged inside; the upper discharge port of the evaporator (3) is connected to the material inlet of the heat exchanger (5), the material outlet of the heat exchanger (5) is connected to the negative pressure condensation tank (6), and the lower end of the negative pressure condensation tank (6) is connected to the second sewage pipe; The pipelines connecting the equipment rooms are all equipped with control valves, and the pipelines requiring the fluid conveying equipment to provide conveying power are all equipped with conveying pumps. The evaporator (3) is equipped with a first liquid level sensor, and the four ports of the heat exchanger (5) are all equipped with temperature sensors. The heat exchanger (5) also includes a PLC controller, which is electrically connected to the control valve, the first liquid level sensor, the temperature sensor, and the motor inverter. The motor inverter and the conveying pump are electrically connected.
2. The device for evaporating high-salt organic wastewater by recovering waste heat from a water source heat pump according to claim 1 is characterized in that: The circulation pipeline is connected to the lower port of the evaporation coil, and a circulation pump (11) is installed on this section of the pipeline; the upper port of the evaporation coil is connected back to the temperature-increasing pipeline through the circulation pipeline.
3. The device for evaporating high-salt organic wastewater by recovering waste heat from a water source heat pump according to claim 1, characterized in that: The shell-side inlet and outlet of the heat exchanger (5) are refrigerant inlets and outlets, and are in the form of bottom-in and top-out, while the tube-side inlet and outlet are material inlets and outlets.
4. The device for evaporating high-salt organic wastewater by recovering waste heat from a water source heat pump according to claim 1 is characterized in that: The negative pressure condensation tank (6) is connected to a vacuum pump (14).
5. The device for evaporating high-salt organic wastewater by recovering waste heat from a water source heat pump according to claim 1 or 4, characterized in that: The liquid outlet of the negative pressure condensation tank (6) is connected to a buffer tank (7), and the liquid outlet of the buffer tank (7) is connected to the second sewage discharge pipe, and the second sewage discharge pipe is provided with a second sewage discharge pump (13); the buffer tank (7) is equipped with a second liquid level sensor, a pressure sensor and a pressure balancing valve, and the second liquid level sensor, the pressure sensor and the pressure balancing valve are electrically connected to the PLC controller.
6. The device for evaporating high-salt organic wastewater by recovering waste heat from a water source heat pump according to claim 1, characterized in that: The first sewage discharge pipe is connected to an evaporative dryer (9).
7. The device for evaporating high-salt organic wastewater by recovering waste heat from a water source heat pump according to claim 1, characterized in that: The heat exchange medium is water or oil.
8. The device for evaporating high-salt organic wastewater by recovering waste heat from a water source heat pump according to claim 1, characterized in that: At least two groups of evaporating kettles (3) are provided and connected in parallel.