Heat exchange system based on membrane distillation principle

Abstract

The invention relates to a heat exchange system based on a membrane distillation principle, which comprises a thermal circulation pipeline and a cold circulation pipeline, a membrane distillation assembly is connected between the thermal circulation pipeline and the cold circulation pipeline, the thermal circulation pipeline and the cold circulation pipeline realize heat and moisture transfer through the membrane distillation assembly, and a backflow water supplementing pipeline is also connected between the thermal circulation pipeline and the cold circulation pipeline. And pure water in the cold circulation pipeline is supplemented into the hot circulation pipeline, so that the concentration of a hot solution and the pressure of the cold circulation pipeline can be controlled. The membrane distillation evaporation refrigeration principle is integrated to the heat exchange system, the corrosion-resistant organic membrane material is adopted, efficient and stable operation can be achieved in the high-temperature and high-corrosion environment, and the heat management requirement under the special working condition is met.

Description

Technical Field

[0001] The present invention relates to a heat exchange system based on the principle of membrane distillation, and relates to the technical field of heat exchange. Background Art

[0002] Existing heat exchange equipment usually adopts plate heat exchangers, tubular heat exchangers or other direct heat exchange methods. These devices are highly efficient when dealing with ordinary liquids, but when facing corrosive fluids, such as high-concentration alkaline solutions or electrolyte solutions, their material and structural designs are limited, and there are problems such as short service life and high maintenance costs. To extend the equipment life, some heat exchangers use anti-corrosion coatings to enhance chemical resistance. However, the anti-corrosion coatings are prone to aging and peeling under complex working conditions, affecting the protection effect. Since the thermal conductivity of the coating is lower than that of the metal substrate, the overall heat conduction efficiency is also limited. In addition, the manufacturing and maintenance costs of the coating are relatively high, further increasing the operation burden of the equipment. These limitations restrict the wide application of traditional heat exchangers under special working conditions, and there is an urgent need for a new heat exchange system that combines high corrosion resistance and high heat exchange efficiency to meet the requirements. Summary of the Invention

[0003] In view of the deficiencies of the prior art, the technical problem to be solved by the present invention is to provide a heat exchange system based on the principle of membrane distillation.

[0004] To solve the above technical problem, the technical solution of the present invention is: a heat exchange system based on the principle of membrane distillation, including a hot cycle pipeline and a cold cycle pipeline. A membrane distillation module is connected between the hot cycle pipeline and the cold cycle pipeline, and heat and moisture are transferred between the two through the membrane distillation module. A reflux make-up water pipeline is also connected between the hot cycle pipeline and the cold cycle pipeline to replenish pure water in the cold cycle pipeline back into the hot cycle pipeline to facilitate controlling the concentration of the hot solution and the pressure of the cold cycle pipeline.

[0005] Preferably, the membrane distillation module includes a housing. Inside the housing, a hot solution flow channel and a cold water flow channel of the membrane distillation module are separated by an organic membrane. The hot solution flow channel of the membrane distillation module is connected to the hot cycle pipeline, and the cold water flow channel of the membrane distillation module is connected to the cold cycle pipeline.

[0006] Preferably, the hot cycle pipeline includes a hot-end solution tank. A gate valve and a pressure gauge are sequentially arranged along the fluid flow direction between the outlet of the hot-end solution tank and the hot solution flow channel of the membrane distillation module.

[0007] Preferably, a corrosion-resistant pump and a gate valve are sequentially arranged along the fluid flow direction between the hot solution flow channel of the membrane distillation module and the inlet of the hot-end solution tank.

[0008] Preferably, the cold circulation pipeline includes a refrigeration device, and a gate valve and a circulation pump are sequentially arranged between the outlet of the refrigeration device and the cold water flow channel of the membrane distillation module along the fluid flow direction.

[0009] Preferably, a pressure gauge and a gate valve are sequentially arranged between the cold water flow channel of the membrane distillation module and the inlet of the refrigeration device along the fluid flow direction.

[0010] Preferably, the reflux make-up water pipeline is connected between the corrosion-resistant pump in the hot circulation pipeline and the circulation pump in the cold circulation pipeline.

[0011] Preferably, a safety valve, a gate valve, a turbine power generation device, and a corrosion-resistant check valve are sequentially arranged on the reflux make-up water pipeline along the fluid flow direction.

[0012] Preferably, the pipes and pipe fittings in the hot circulation pipeline are all subjected to anti-corrosion treatment.

[0013] Preferably, heat insulation layers are respectively arranged on the cold circulation pipeline and the cold end of the membrane distillation module to maintain the cold circulation temperature.

[0014] Compared with the prior art, the present invention has the following beneficial effects: The present invention integrates the membrane distillation evaporation refrigeration principle into the heat exchange system and uses a corrosion-resistant organic membrane material, which can operate efficiently and stably in high-temperature and highly corrosive environments and meet the heat management requirements under special working conditions.

[0015] The following further describes the present invention in detail with reference to the drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic structural diagram of an embodiment of the present invention.

[0017] Figure 2 It is a working schematic diagram of a plate distillation membrane.

[0018] Figure 3 It is a working schematic diagram of a tubular distillation membrane.

[0019] In the figure: 1. Organic membrane; 2. Hot circulation pipeline; 3. Cold circulation pipeline; 4. Hot solution flow channel of the membrane distillation module; 5. Cold water flow channel of the membrane distillation module; 6. Hot end solution tank; 7. Corrosion-resistant pump; 8. Circulation pump; 9. Refrigeration device; 10. Corrosion-resistant check valve; 11. Turbine power generation device; 12. Pressure gauge; 13. Safety valve; 14. Reflux make-up water pipeline; 15. Gate valve. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] The following further describes the present invention with reference to the drawings and embodiments.

[0021] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs.

[0022] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0023] As Figure 1 shown, this embodiment provides a heat exchange system based on the principle of membrane distillation, which is particularly suitable for heat exchange and cooling of corrosive liquids. It includes a hot circulation pipeline 2 and a cold circulation pipeline 3. A membrane distillation module is connected between the hot circulation pipeline and the cold circulation pipeline. The hot circulation pipeline contains a corrosive hot solution, and the cold circulation pipeline contains pure water. Heat and moisture transfer are achieved between the two through the membrane distillation module. A reflux make-up water pipeline 14 is also connected between the hot circulation pipeline and the cold circulation pipeline to replenish the pure water in the cold circulation pipeline back into the hot circulation pipeline to facilitate controlling the concentration of the hot solution and the pressure of the cold circulation pipeline.

[0024] This system isolates the hot and cold end liquids through an organic membrane and uses the vapor pressure difference at both ends to drive water evaporation and condensation, efficiently transferring the heat of the hot end solution to the cold end pure water. At the same time, the system maintains the concentration and circulation stability of the hot solution through a reflux make-up water mechanism. The reflux make-up water pipeline connects the hot circulation pipeline and the cold circulation pipeline, replenishes the water transferred to the cold circulation pipeline back into the hot circulation pipeline, cools the hot solution again, and controls the concentration of the hot solution and the pressure of the cold circulation pipeline. And the connection is designed in front of the corrosion-resistant pump to assist the liquid flow movement of the hot circulation. For a system using a corrosion-resistant pump and other water pump devices in contact with the solution, confluence here can reduce the concentration of the corrosive solution and slow down the corrosion of the water pump.

[0025] The present invention integrates the principle of membrane distillation evaporation refrigeration into the heat exchange system and uses a corrosion-resistant organic membrane material, which can operate efficiently and stably in high-temperature and highly corrosive environments and meet the heat management requirements under special working conditions.

[0026] In the embodiment of the present invention, the membrane distillation module includes a housing. Inside the housing, a membrane distillation module hot solution flow channel 4 and a membrane distillation module cold water flow channel 5 are separated by an organic membrane 1. The membrane distillation module hot solution flow channel is connected to the hot circulation pipeline, and the membrane distillation module cold water flow channel is connected to the cold circulation pipeline.

[0027] Isolate using an organic membrane, and achieve the evaporation and condensation of the hot solution through the vapor pressure difference between the hot end and the cold end to complete the heat exchange. The material of the organic membrane can remain stable in a high-temperature, high-salt or high-concentration corrosive liquid environment.

[0028] In the embodiment of the present invention, as Figure 2 , 3 shown, there are various choices for the form and material of the membrane used in membrane separation. The membrane distillation module can adopt forms such as plate membranes, tubular membranes, or hollow fiber membranes, and a suitable distillation membrane material can be selected according to the properties of the hot solution. Among them, flat membranes and tubular membranes are common forms and are suitable for membrane distillation systems.

[0029] In the embodiment of the present invention, the hot circulation pipeline includes a hot-end solution tank 6. A gate valve 15 and a pressure gauge are sequentially arranged along the fluid flow direction between the outlet of the hot-end solution tank and the hot-solution flow channel of the membrane distillation module.

[0030] In the embodiment of the present invention, a corrosion-resistant pump 7 and a gate valve are sequentially arranged along the fluid flow direction between the hot-solution flow channel of the membrane distillation module and the inlet of the hot-end solution tank.

[0031] In the embodiment of the present invention, the cold circulation pipeline includes a refrigeration device 9. A gate valve and a circulation pump 8 are sequentially arranged along the fluid flow direction between the outlet of the refrigeration device and the cold-water flow channel of the membrane distillation module.

[0032] The cold circulation pipeline is connected to the cold-end refrigeration device, and the operating state of the cold circulation liquid is monitored in real time through temperature sensors and pressure sensors, and the operating parameters of the refrigeration device and the pump are adjusted to maintain the stability of the system.

[0033] Temperature and pressure sensors are arranged in the hot circulation pipeline to detect the temperature and pressure of the hot circulation system, and the pressure is controlled by adjusting the pumping system.

[0034] A corrosion-resistant pump is arranged in the hot circulation pipeline, and a conventional circulation pump is arranged in the cold circulation pipeline. The two drive the liquid flow respectively, and the flow rate and pressure are adjusted through a control device.

[0035] In the embodiment of the present invention, a pressure gauge 12 and a gate valve are sequentially arranged along the fluid flow direction between the cold-water flow channel of the membrane distillation module and the inlet of the refrigeration device.

[0036] In the embodiment of the present invention, the reflux make-up water pipeline is connected between the corrosion-resistant pump in the hot circulation pipeline and the circulation pump in the cold circulation pipeline.

[0037] In the embodiment of the present invention, a safety valve 13, a gate valve, a turbine power generation device 11, and a corrosion-resistant check valve 10 are sequentially arranged along the fluid flow direction on the reflux make-up water pipeline. The corrosion-resistant check valve prevents the hot solution from flowing back into the cold circulation system and polluting and corroding the pipeline and equipment.

[0038] According to the backflow water pressure condition, a turbine power generation device can be set up to recover part of the head energy and convert it into electric energy for power supply to the equipment in the system, reducing the energy consumption during system operation. A check valve and a safety valve are installed in the backflow make-up water pipeline. The connection with the heat circulation pipeline is set in the pipeline downstream of the membrane distillation module and upstream of the corrosion-resistant pump, and the cutting-in direction should conform to the heat circulation flow direction to assist in promoting the liquid flow in the heat circulation system, reducing the energy consumption of the water pump, and diluting the corrosive solution before it enters the water pump to slow down its corrosion to the pump structural materials.

[0039] In the embodiment of the present invention, the pipes and pipe fittings in the heat circulation pipeline are all subjected to anti-corrosion treatment.

[0040] In the embodiment of the present invention, heat insulation layers are respectively provided on the cold circulation pipeline and the cold end of the membrane distillation module to maintain the cold circulation temperature.

[0041] In the embodiment of the present invention, membrane distillation technology is a heat-driven membrane separation process. Its core principle is to achieve the dual transfer of matter and energy through the vapor pressure difference between the hot end and the cold end. In this process, the high-temperature liquid at the hot end passes through the semi-permeable membrane to transfer gaseous water molecules to the cold end, completing the transfer of water and heat. Compared with traditional heat exchangers, not only heat conduction exists in membrane distillation, but also the latent heat of vaporization of water evaporation is added. Membrane distillation technology can not only efficiently utilize heat energy while separating liquid components, but also maintain high efficiency in high-temperature and corrosive environments. The membrane distillation heat exchange system uses an organic membrane material with excellent corrosion resistance to ensure stable heat transfer in a highly corrosive liquid environment, avoiding the damage problem of traditional heat exchangers when contacting corrosive liquids. This heat exchange system designed based on the principle of membrane distillation provides a solution for the heat transfer requirements in complex industrial environments. Membrane distillation is applicable to water treatment and resource recovery applications in extreme environments such as high salinity and high temperature.

[0042] In this system, heat exchange occurs between the hot and cold liquids in the membrane distillation module. At the same time, due to the principle of membrane distillation, the water in the hot solution evaporates to lose more heat, and drives the transfer of water molecules to the cold circulation pipeline. To control the concentration of the hot circulation solution and reduce the pressure in the cold circulation pipeline, the water transferred in the membrane distillation module will be replenished back to the hot circulation through the backflow make-up water pipeline, and the hot solution in the hot circulation will be cooled again during this process. Through three heat exchange processes: membrane interface heat exchange, steam heat loss, and cold water replenishment, the heat in the hot solution is converted to the refrigeration equipment.

[0043] Membrane interface heat exchange: The hot solution is driven by the corrosion-resistant pump, enters the heat circulation pipeline and flows in the pipeline. The hot solution flows into the hot solution flow channel of the membrane distillation module and undergoes heat exchange with the cold circulation side inside the membrane module. This is the first heat exchange channel.

[0044] Steam heat loss: In the membrane distillation module, due to the vapor pressure difference between the hot cycle side and the cold cycle side, the water in the hot solution is transferred to the cold cycle in gaseous form, and the heat loss of the hot solution mainly drives this process. This is the second heat exchange channel.

[0045] Cold water make-up: Due to the characteristic that the membrane distillation produces pure water in the cold cycle, the concentration of the solution in the hot cycle will change, and the pressure in the cold cycle pipeline will increase. For the stable operation of the system, the pure water in the cold cycle pipeline is made up to the hot cycle pipeline at a certain flow rate by using the reflux make-up water. In this process, the low-temperature pure water converges with the hot solution, and the hot solution is cooled again. This is the third heat exchange channel.

[0046] The membrane distillation module is the core part of the heat exchange system. It is internally provided with flow channels and loaded with a distillation organic membrane. The organic membrane is divided into an inlet side (hot end) and an outlet side (cold end) inside the module. The hot-side fluid and the cold-side fluid flow in the flow channels on both sides of the membrane respectively, and water vapor transfer and heat exchange are carried out through the membrane. In this process, the hot water on the membrane surface will be cooled, the cold water on the other side will be heated, and at the same time, membrane distillation water production occurs, and the heat in the hot water is consumed again in the form of water evaporation.

[0047] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention in other forms. Any person skilled in the art may use the technical content disclosed above to make changes or modifications into equivalent embodiments with equivalent changes. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the technical solution content of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A heat exchange system based on the membrane distillation principle, characterized in that: It includes a hot circulation pipeline and a cold circulation pipeline, between which a membrane distillation component is connected, and the two realize heat and water transfer through the membrane distillation component. A reflux water replenishment pipeline is also connected between the hot circulation pipeline and the cold circulation pipeline, which is used to replenish the pure water in the cold circulation pipeline to the hot circulation pipeline, so as to facilitate the control of the hot solution concentration and the cold circulation pipeline pressure.

2. The heat exchange system based on the membrane distillation principle according to claim 1, characterized in that: The membrane distillation component comprises a shell, the interior of which is separated by an organic membrane into a membrane distillation component hot solution flow channel and a membrane distillation component cold water flow channel, the membrane distillation component hot solution flow channel is connected to a heat circulation pipeline, and the membrane distillation component cold water flow channel is connected to a cold circulation pipeline.

3. The heat exchange system based on the membrane distillation principle according to claim 2, characterized in that: The heat circulation pipeline comprises a hot end solution tank, and gate valves and pressure gauges are sequentially arranged between the outlet of the hot end solution tank and the hot solution flow channel of the membrane distillation component along the fluid flow direction.

4. The heat exchange system based on the membrane distillation principle according to claim 3, characterized in that: A corrosion-resistant pump and a gate valve are arranged in sequence along the fluid flow direction between the hot solution flow channel of the membrane distillation component and the inlet of the hot end solution tank.

5. The heat exchange system based on the membrane distillation principle according to claim 2, characterized in that: The cold circulation pipeline comprises a refrigeration device, and a gate valve and a circulation pump are sequentially arranged between the outlet of the refrigeration device and the cold water flow channel of the membrane distillation component along the flow direction of the fluid.

6. The heat exchange system based on the membrane distillation principle according to claim 5, characterized in that: A pressure gauge and a gate valve are arranged in sequence along the fluid flow direction between the cold water flow channel of the membrane distillation component and the inlet of the refrigeration equipment.

7. The heat exchange system based on the membrane distillation principle according to claim 1, characterized in that: The reflux water supply pipeline is connected between the corrosion-resistant pump of the hot circulation pipeline and the circulation pump of the cold circulation pipeline.

8. The heat exchange system based on the membrane distillation principle according to claim 1, characterized in that: A safety valve, a gate valve, a turbine power generation device, and a corrosion-resistant check valve are sequentially arranged on the reflux water supply pipeline along the fluid flow direction.

9. The heat exchange system based on the membrane distillation principle according to claim 1, characterized in that: The pipes and pipe fittings in the heat circulation pipeline are all treated with anti-corrosion.

10. The heat exchange system based on the membrane distillation principle according to claim 1, characterized in that: The cold cycle pipeline and the cold end of the membrane distillation component are respectively provided with a thermal insulation layer for maintaining the cold cycle temperature.

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