Boiler continuous drainage waste heat recovery and membrane distillation energy storage system based on absorption heat pump

Abstract

The embodiment of the invention provides a boiler continuous drainage waste heat recovery and membrane distillation energy storage system based on an absorption heat pump, and the system comprises a phase change heat storage device which is used for receiving continuous drainage discharged by a boiler and storing waste heat of the continuous drainage; the absorption heat pump device is connected with the phase change heat storage device through a heat conduction oil pipeline so as to receive the heat conduction oil subjected to heat exchange through the phase change heat storage device; the membrane distillation device is connected with the absorption type heat pump device so as to receive the high-grade heat output by the absorption type heat pump device; and the hot water supply device is respectively connected with the phase change heat storage device and the absorption heat pump device so as to receive continuous drainage waste heat output by the phase change heat storage device and low-grade heat output by the absorption heat pump device.

Description

Technical Field

[0001] The embodiments disclosed herein belong to the field of energy supply technology, specifically relating to a boiler waste heat recovery and membrane distillation energy storage system based on an absorption heat pump. Background Technology

[0002] In industrial production and energy supply, boilers are crucial heat energy conversion devices, widely used in industries such as power, chemical, and metallurgy. During boiler operation, to ensure stable water quality and prevent scaling and corrosion, high-salinity boiler water needs to be discharged through continuous blowdown (continuous drainage) and periodic blowdown. Continuous drainage typically involves high temperatures and pressures and contains a large amount of underutilized heat energy and moisture. Direct discharge of this water not only wastes energy but also increases wastewater treatment costs, failing to meet the sustainable development requirements of energy conservation and emission reduction.

[0003] Therefore, there is an urgent need to develop an efficient and reliable boiler wastewater recycling technology to achieve the synergistic recovery of heat energy and water resources, reduce energy consumption and operating costs, and meet environmental protection requirements. Summary of the Invention

[0004] The embodiments disclosed herein aim to at least solve one of the technical problems existing in the prior art, and provide a boiler waste heat recovery and membrane distillation energy storage system based on an absorption heat pump.

[0005] One aspect of the embodiments of this disclosure provides a boiler continuous drainage waste heat recovery and membrane distillation energy storage system based on an absorption heat pump, comprising: a phase change heat storage device for receiving continuous drainage discharged from the boiler and storing the waste heat of the continuous drainage.

[0006] An absorption heat pump device is connected to the phase change heat storage device via a heat transfer oil pipeline to receive the heat transfer oil that has been heat-exchanged by the phase change heat storage device.

[0007] A membrane distillation apparatus, wherein the membrane distillation apparatus is connected to the absorption heat pump apparatus to receive high-grade heat output from the absorption heat pump apparatus;

[0008] A heating water device is connected to both the phase change thermal storage device and the absorption heat pump device to receive the waste heat from the continuous drainage output of the phase change thermal storage device and the low-grade heat output of the absorption heat pump device.

[0009] Optionally, the phase change thermal storage device includes a phase change thermal storage tank, a phase change material disposed in the phase change thermal storage tank, and a connecting drain pipe passing through the interior of the phase change thermal storage tank, wherein the input end of the connecting drain pipe is used to receive the connecting drain discharged from the boiler, and the output end of the connecting drain pipe is connected to the heating water device.

[0010] Optionally, the drain pipe is arranged in a serpentine bend within the phase change thermal storage tank.

[0011] Furthermore, the phase change thermal storage device also includes an insulation layer, which covers the inner peripheral wall of the phase change thermal storage tank.

[0012] Optionally, the phase change thermal storage device further includes a plurality of heat exchange fins, which are spaced apart along the length of the connecting drainage pipe.

[0013] Furthermore, the phase change thermal energy storage device also includes a continuous drainage flow regulating valve, which is located at the inlet end of the continuous drainage pipe.

[0014] Furthermore, it also includes: a heat transfer oil flow regulating valve, which is installed in the heat transfer oil pipeline.

[0015] Optionally, the absorption heat pump device includes a generator connected to the phase change heat storage device via a heat transfer oil pipeline, a condenser connected to the generator and the membrane distillation device respectively, an evaporator connected to the condenser, the heating water device and the membrane distillation device respectively, and an absorber connected to the generator, the evaporator and the heating water device respectively.

[0016] Optionally, the membrane distillation device includes a distillation tank and a hydrophobic microporous membrane disposed within the distillation tank and defining a high-temperature side and a low-temperature side within the distillation tank; wherein the high-temperature side of the membrane distillation device is connected to the absorption heat pump device via a heat exchange tube to receive heat from the phase change heat storage device through the heat exchange tube.

[0017] Optionally, the heat exchange tubes are arranged in a serpentine bend within the high-temperature side of the membrane distillation apparatus.

[0018] The beneficial effects of the embodiments of this disclosure include:

[0019] 1. Achieve three-stage coupling of heat storage, heat pump, and membrane distillation, integrating phase change heat storage, absorption heat pump, and membrane distillation to realize the "temperature-matched" utilization of waste heat.

[0020] 2. Implement waste heat cascade utilization, decompose the heat of the wastewater into high-grade heat and low-grade heat. The high-grade heat is used to drive membrane distillation, and the low-grade heat is used to heat the heating water, thereby realizing the cascade utilization of waste heat and improving the waste heat utilization rate of the system.

[0021] 3. Reduce system energy consumption by using continuous drainage to generate high-grade heat through a heat pump system, replacing the original electrically heated membrane distillation, thus reducing system energy consumption.

[0022] 4. Maintain system operational stability by utilizing the phase change thermal energy storage system to adapt to fluctuations in continuous discharge volume caused by changes in boiler load, and maintain continuous operation of the heat pump and membrane distillation energy storage system.

[0023] 5. Resource recycling: Use membrane distillation energy storage system to recover fresh water from wastewater and recycle it. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of a boiler waste heat recovery and membrane distillation energy storage system based on an absorption heat pump, according to an embodiment of the present disclosure.

[0025] Figure 2 This is a schematic diagram of a boiler waste heat recovery and membrane distillation energy storage system based on an absorption heat pump, according to another embodiment of the present disclosure.

[0026] Figure 3 This is a schematic diagram of the structure of a phase change thermal energy storage device according to an embodiment of the present disclosure.

[0027] In the diagram, 1. Phase change thermal storage device; 2. Absorption heat pump device; 3. Membrane distillation device; 4. Heating water device; 11. Phase change thermal storage tank; 12. Insulation layer; 13. Phase change material; 14. Drainage pipe; 15. Heat exchange fins; 16. Heat transfer oil pipe; 17. Drainage flow regulating valve; 18. Heat transfer oil flow regulating valve; 21. Generator; 22. Condenser; 23. Evaporator; 24. Absorber; 25. Throttling valve; 26. Booster pump; 31. High temperature side; 32. Low temperature side; 33. Hydrophobic microporous membrane; 34. Heat exchange tube; 41. Plate heat exchanger. Detailed Implementation

[0028] To enable those skilled in the art to better understand the technical solutions of this disclosure, the disclosure will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] The embodiments of this application will be further described in detail below with reference to the accompanying drawings and examples. The detailed descriptions and accompanying drawings of the following embodiments are used to exemplarily illustrate the principles of this application, but should not be used to limit the scope of this application; that is, this application is not limited to the described embodiments. In the description of this application, it should be noted that, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," etc., indicating orientation or positional relationships are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. "Vertical" is not strictly vertical, but within the allowable error range. "Parallel" is not strictly parallel, but within the allowable error range.

[0030] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joining" 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 direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application depending on the specific circumstances.

[0031] like Figure 1-3 As shown, a boiler continuous wastewater heat recovery and membrane distillation energy storage system based on an absorption heat pump includes a phase change heat storage device 1, an absorption heat pump device 2, a membrane distillation device 3, and a heating water device 4. The phase change heat storage device 1 is used to receive and store the waste heat of the continuous wastewater discharged from the boiler. The absorption heat pump device 2 is connected to the phase change heat storage device 1 through a heat transfer oil pipeline 16 to receive the heat transfer oil that has been heat-exchanged by the phase change heat storage device 1.

[0032] The membrane distillation device 3 is connected to the absorption heat pump device 2 to receive the high-grade heat output by the absorption heat pump device 2. The heating water device 4 is connected to both the phase change thermal storage device 1 and the absorption heat pump device 2 to receive the waste heat from the continuous drainage output by the phase change thermal storage device 1 and the low-grade heat output by the absorption heat pump device 2.

[0033] refer to Figure 3 In some embodiments, the phase change thermal storage device 1 includes a phase change thermal storage tank 11, a phase change material 13 disposed in the phase change thermal storage tank 11, and a connecting drain pipe 14 passing through the interior of the phase change thermal storage tank 11. The input end of the connecting drain pipe 14 is used to receive the connecting drain discharged from the boiler, and the output end of the connecting drain pipe 14 is connected to the heating water device 4.

[0034] In some embodiments, the drain pipe 14 is arranged in a serpentine bend within the phase change thermal storage tank 11.

[0035] In some embodiments, the phase change thermal storage device 1 further includes an insulation layer 12, which covers the inner peripheral wall of the phase change thermal storage tank 11.

[0036] In some embodiments, the phase change thermal storage device 1 further includes a plurality of heat exchange fins 15, which are spaced apart along the length of the connecting drain pipe 14.

[0037] In some embodiments, the phase change thermal energy storage device 1 further includes a continuous drainage flow regulating valve 17, which is disposed at the input end of the continuous drainage pipe 14.

[0038] In some embodiments, the waste heat recovery and membrane distillation energy storage system further includes a heat transfer oil flow regulating valve 18, which is disposed in the heat transfer oil pipeline 16.

[0039] In some embodiments, the absorption heat pump device 2 includes a generator 21 connected to the phase change heat storage device 1 via a heat transfer oil pipe 16, a condenser 22 connected to the generator 21 and the membrane distillation device 3 respectively, an evaporator 23 connected to the condenser 22, the heating water device 4 and the membrane distillation device 3 respectively, and an absorber 24 connected to the generator 21, the evaporator 23 and the heating water device 4 respectively.

[0040] In some embodiments, the membrane distillation device 3 includes a distillation tank and a hydrophobic microporous membrane 33 disposed within the distillation tank and defining a high-temperature side 31 and a low-temperature side 32 within the distillation tank. The high-temperature side 31 of the membrane distillation device 3 is connected to the absorption heat pump device 2 via a heat exchange tube 34 to receive heat from the phase change heat storage device 1 through the heat exchange tube 34.

[0041] In some embodiments, the heat exchange tube 34 is arranged in a serpentine bend within the high-temperature side 31 of the membrane distillation apparatus 3.

[0042] For details, please refer to the following: Figure 2 The processing includes:

[0043] I. Phase Change Thermal Storage Device 1 The core of the absorption heat pump device 2 is the heat transfer and storage of heat by heat transfer oil, and the reverse drainage linkage heating / heat pump cycle.

[0044] Heat transfer oil circuit (heat transfer): In phase change heat storage device 1, the 180°C water discharge releases heat to store heat in the phase change material, heating the heat transfer oil to 145°C. The 145°C heat transfer oil is then transported through heat transfer oil pipeline 16 to the generator 21 of the absorption heat pump device, providing a heat source for the decomposition of ammonia solution. After releasing heat in generator 21, the heat transfer oil cools to 110°C and returns to phase change heat storage device 1 through the heat transfer oil pipeline, completing the heat transfer oil cycle of "heat storage → heat pump → heat storage".

[0045] Reverse drainage loop (continuous drainage cycle): After releasing heat from the 180°C continuous drainage in phase change heat storage device 1, the temperature drops to 150°C (reverse drainage). It is then transported through pipelines to the plate heat exchanger 41 of heating water device 4 to heat the heating water. After releasing heat in the plate heat exchanger, the reverse drainage cools to 70°C and is then transported through pipelines to the evaporator 23 of absorption heat pump device 2 to participate in the heat pump cycle, completing the continuous drainage cycle of "heat storage → heating → heat pump".

[0046] II. Absorption Heat Pump Unit 2 The core of the membrane distillation unit 3 is high-grade thermally driven membrane distillation and wastewater conveyance.

[0047] High-grade heat transfer (energy-driven): Ammonia gas at 150°C releases heat in the condenser 22 of the absorption heat pump unit 2, heating the circulating water to 120°C (high-grade heat). The 120°C high-grade heat is transferred to the high-temperature side 31 of the membrane distillation unit through the heat exchange tube 34, providing energy for the reheating of the continuous drainage (replacing electric heating).

[0048] Wastewater supply (water source): In the evaporator 23 of the absorption heat pump device 2, the 70°C wastewater is discharged and cooled to 60°C. The 60°C wastewater is then transported through a pipeline to the high-temperature side 31 of the membrane distillation device as the wastewater source for membrane distillation.

[0049] III. Absorption Heat Pump Unit 2 The core of the heating water device 4 is a two-stage heating system for low-grade hot water, which is connected to a closed-loop drainage system.

[0050] Low-grade heat supply (thermal energy utilization): The heating water (initial 40℃) first enters the absorber 24 of the absorption heat pump device 2. After absorbing the heat released during the mixing process of ammonia solution, it is heated to 60℃. The 60℃ heating water is transported through pipelines to the plate heat exchanger 41 of the heating water device 4 and undergoes secondary heat exchange with the 150℃ backflow. After being heated to 80℃, it is transported to the plant area for heating.

[0051] Continuous drainage cycle (material closed loop): The 70°C backflow after the plate heat exchanger 41 in the heating water device 4 releases heat is transported through the pipeline to the evaporator 23 of the absorption heat pump, completing the continuous drainage cycle of "heating → heat pump".

[0052] IV. The internal and external connections of membrane distillation unit 3 are based on the steam pressure difference driving freshwater separation, which is linked to the heat pump heat energy and water source.

[0053] Internal membrane distillation process: The membrane distillation device 3 is divided into a high-temperature side 31 (drainage side) and a low-temperature side 32 (condensate side), separated by a hydrophobic microporous membrane 33. In the high-temperature side 31, the 60°C drainage is heated to 80°C by a high-grade heat source at 120°C, generating high water vapor pressure. The low-temperature side 32 is supplied with 30°C condensate (low water vapor pressure). Under the vapor pressure difference, water vapor molecules diffuse through the hydrophobic microporous membrane 33 to the low-temperature side, where they condense into fresh water. This fresh water is then mixed with the condensate and recycled.

[0054] External linkage heat pump: The heat on the high-temperature side 31 comes from the high-grade heat of the absorption heat pump condenser 22, and the wastewater to be treated comes from the 60℃ wastewater of the absorption heat pump evaporator 23, realizing the coupling of "heat pump heat energy → membrane distillation desalination recovery".

[0055] In this application, 1. Waste heat is utilized in a cascade manner. The heat from the wastewater is broken down into high-grade heat and low-grade heat. The high-grade heat is used to drive membrane distillation, and the low-grade heat is used to heat the heating water.

[0056] 2. Reduce system energy consumption. Use high-grade heat instead of electric heating to drive membrane distillation.

[0057] 3. Maintain system operational stability. Utilize phase change thermal storage devices to adapt to fluctuations in continuous discharge volume caused by changes in boiler load, thus maintaining continuous operation of the heat pump and membrane distillation unit.

[0058] 4. Resource recycling. Fresh water in the wastewater is recovered using a membrane distillation device and recycled.

[0059] Specifically, the boiler waste heat recovery and membrane distillation device based on absorption heat pump consists of a phase change heat storage device 1, an absorption heat pump device 2, a membrane distillation device 3, and a heating water device 4.

[0060] The phase change thermal storage device 1 includes a phase change thermal storage tank 11. The insulation layer 12 of the phase change thermal storage tank 11 is made of aluminum silicate fiber. The phase change material 13 filled inside the phase change thermal storage tank 11 is composed of paraffin wax and graphite, with a phase change temperature of 150-170℃. 180℃ wastewater discharged from the boiler releases heat within the phase change thermal storage tank 11 through a drain pipe 14, heating the phase change material 13 from a solid state to a liquid state. The phase change material 13 absorbs a large amount of heat, including sensible and latent heat. The drain pipe 14 is a serpentine heat exchange tube with numerous heat exchange fins 15 of the same material welded onto it, enhancing heat exchange by increasing the heat exchange area. A heat transfer oil pipe 16 is arranged inside the phase change thermal storage tank 11. The heat transfer oil flows through the heat transfer oil pipe 16, absorbing the heat stored in the phase change material and heating it from 110℃ to 145℃, providing sufficient heat for the subsequent absorption heat pump. The continuous drainage flow regulating valve 17 and the heat transfer oil flow regulating valve 18 adjust the continuous drainage flow rate and the heat transfer oil flow rate to cope with the changes in continuous drainage volume caused by boiler load fluctuations, thereby providing a stable driving heat source for the absorption heat pump unit 2.

[0061] The absorption heat pump device 2 mainly consists of a generator 21, a condenser 22, an evaporator 23, and an absorber 24. The main working fluid circulating inside the heat pump system is a 40% concentrated ammonia solution. Inside the generator 21, the 80°C concentrated ammonia solution exchanges heat with the high-temperature heat transfer oil that has absorbed sufficient heat in the phase change heat storage tank 11. After absorbing heat, the concentrated ammonia solution decomposes into a 120°C 20% dilute ammonia solution and 150°C ammonia gas. The 150°C ammonia gas heats the circulating water in the condenser 22, raising it from 90°C to 120°C. This high-grade heat is used in the membrane distillation device 3 to replace the original electric heating for heating the wastewater. Simultaneously, the ammonia gas, after releasing heat, is condensed into a 50°C ammonia solution. After the ammonia solution exits from condenser 22, its pressure decreases after passing through throttling valve 25, further reducing the saturation temperature of the ammonia solution to below 60°C. Inside condenser 22, the low-temperature, low-pressure ammonia solution exchanges heat with the 70°C wastewater flowing from heating water device 4, absorbing a certain amount of heat to become 60°C ammonia gas. The wastewater releases heat, reducing its temperature to 60°C, and then enters membrane distillation device 3 for wastewater recycling. Before entering absorber 24, the 60°C ammonia gas mixes with the 120°C dilute ammonia solution exiting generator 21, forming a 120°C concentrated ammonia solution. This solution then exchanges heat with the low-temperature heating water, heating it from 40°C to 60°C as low-grade heat. After heat exchange, the concentrated ammonia solution decreases from 120°C to 80°C, is pressurized by booster pump 26, and then re-enters generator 21 to participate in the reaction again.

[0062] The membrane distillation device 3 is used to extract fresh water from the continuous drainage for recycling. It mainly consists of a high-temperature side 31, a low-temperature side 32, and a hydrophobic microporous membrane 33. After releasing heat from the evaporator 23, the continuous drainage cools to 60°C and enters the high-temperature side 31 for reheating. The continuous drainage is heated to a certain temperature, generating a higher water vapor pressure than the water vapor pressure on the surface of the low-temperature side 32. Under this vapor pressure difference, water vapor molecules diffuse through the hydrophobic microporous membrane 33 to the other side. When the water vapor passes through the hydrophobic microporous membrane 33 to the low-temperature side 32, it condenses rapidly into liquid water due to the lower temperature on this side, thus forming fresh water. This fresh water mixes with the condensate from the low-temperature side 32 and is then output from the system for recycling.

[0063] In the heating water device 4, the heating water undergoes two stages of heating from 40°C. The first stage of heating is performed by the low-grade heat generated by the absorber 24 in the absorption heat pump device 2, heating the heating water from 40°C to 60°C. Then, it is connected to the 150°C drain water after heat exchange in the phase change heat storage device 1, and undergoes a second stage of heating in the plate heat exchanger 41. After the heating water is heated to 80°C, it is used for heating the plant area. The drain water temperature drops to 70°C and enters the evaporator 23 for heat exchange again.

[0064] The beneficial effects of this application include: 1. Realizing a three-stage coupling of heat storage, heat pump, and membrane distillation, integrating phase change heat storage, absorption heat pump, and membrane distillation to achieve "temperature-matched" utilization of waste heat.

[0065] 2. Implement waste heat cascade utilization, decompose the heat of the wastewater into high-grade heat and low-grade heat. The high-grade heat is used to drive membrane distillation, and the low-grade heat is used to heat the heating water, thereby realizing the cascade utilization of waste heat and improving the waste heat utilization rate of the system.

[0066] 3. Reduce system energy consumption by using continuous drainage to generate high-grade heat through a heat pump system, replacing the original electrically heated membrane distillation, thus reducing system energy consumption.

[0067] 4. Maintain system operational stability by utilizing phase change thermal storage devices to adapt to fluctuations in continuous drainage volume caused by changes in boiler load, and maintain continuous operation of the heat pump and membrane distillation unit.

[0068] 5. Resource recycling: Use membrane distillation equipment to recover fresh water from the wastewater and recycle it.

[0069] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of this disclosure, and this disclosure is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and substance of this disclosure, and these modifications and improvements are also considered to be within the scope of protection of this disclosure.

Claims

1. A boiler continuous waste heat recovery and membrane distillation energy storage system based on an absorption heat pump, characterized in that, include: Phase change thermal energy storage device, used to receive and store the waste heat of the boiler discharge. An absorption heat pump device is connected to the phase change heat storage device via a heat transfer oil pipeline to receive the heat transfer oil that has been heat-exchanged by the phase change heat storage device. A membrane distillation apparatus, wherein the membrane distillation apparatus is connected to the absorption heat pump apparatus to receive high-grade heat output from the absorption heat pump apparatus; A heating water device is connected to both the phase change thermal storage device and the absorption heat pump device to receive the waste heat from the continuous drainage output of the phase change thermal storage device and the low-grade heat output of the absorption heat pump device.

2. The waste heat recovery and membrane distillation energy storage system according to claim 1, characterized in that, The phase change thermal storage device includes a phase change thermal storage tank, a phase change material disposed inside the phase change thermal storage tank, and a connecting drain pipe passing through the interior of the phase change thermal storage tank. The input end of the connecting drain pipe is used to receive the connecting drain discharged from the boiler, and the output end of the connecting drain pipe is connected to the heating water device.

3. The waste heat recovery and membrane distillation energy storage system according to claim 2, characterized in that, The drainage pipe is arranged in a serpentine bend within the phase change thermal storage tank.

4. The waste heat recovery and membrane distillation energy storage system according to claim 2, characterized in that, The phase change thermal storage device also includes an insulation layer, which covers the inner peripheral wall of the phase change thermal storage tank.

5. The waste heat recovery and membrane distillation energy storage system according to claim 2, characterized in that, The phase change thermal storage device also includes several heat exchange fins, which are spaced apart along the length of the connecting drainage pipe.

6. The waste heat recovery and membrane distillation energy storage system according to claim 1, characterized in that, The phase change thermal energy storage device 1 also includes a continuous drainage flow regulating valve, which is located at the inlet end of the continuous drainage pipe.

7. The waste heat recovery and membrane distillation energy storage system according to claim 1, characterized in that, Also includes: A heat transfer oil flow regulating valve is installed in the heat transfer oil pipeline.

8. The waste heat recovery and membrane distillation energy storage system according to claim 1, characterized in that, The absorption heat pump device includes a generator connected to the phase change heat storage device via a heat transfer oil pipeline, a condenser connected to the generator and the membrane distillation device respectively, an evaporator connected to the condenser, the heating water device and the membrane distillation device respectively, and an absorber connected to the generator, the evaporator and the heating water device respectively.

9. The waste heat recovery and membrane distillation energy storage system according to claim 1, characterized in that, The membrane distillation device includes a distillation tank and a hydrophobic microporous membrane disposed inside the distillation tank and defining a high-temperature side and a low-temperature side inside the distillation tank; wherein, the high-temperature side of the membrane distillation device is connected to the absorption heat pump device through a heat exchange tube to receive heat from the phase change heat storage device through the heat exchange tube.

10. The waste heat recovery and membrane distillation energy storage system according to claim 9, characterized in that, The heat exchange tubes are arranged in a serpentine bend on the high-temperature side of the membrane distillation device.

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