Device and method for deoxidizing circulating water of heat supply network

Abstract

The invention discloses a heat supply network circulating water deoxygenization device and method.The heat supply network circulating water deoxygenization device comprises a water-oxygen separation membrane assembly, the water-oxygen separation membrane assembly comprises a tube shell and a water-oxygen separation membrane arranged in the tube shell, the tube shell is divided into a liquid phase side and a gas phase side through the water-oxygen separation membrane, the liquid phase side is provided with a liquid phase side inlet and a liquid phase side outlet, and the gas phase side is provided with a gas phase side outlet. The gas phase side is provided with a gas phase side outlet; the liquid phase side inlet is connected with a heat supply network circulating water supply pump, an inlet of the heat supply network circulating water supply pump is connected to a heat supply network system, and the liquid phase side outlet is connected to the heat supply network system; the gas phase side outlet is connected with a vacuum pump; and the vacuum pump is used for vacuumizing the gas phase side to form an oxygen concentration difference. Oxygen in heat supply network circulating water is removed through a membrane method, and the corrosion rate of a carbon steel pipeline in a heat supply network system can be greatly reduced without adding chemicals.

Description

Technical Field

[0001] The present invention relates to the technical field of power water treatment, and particularly relates to a device and method for deoxidizing circulating water in a heat network. Background Art

[0002] To save social energy and protect the ecological environment, centralized heating of urban heat networks is adopted in most northern regions and some southern regions. Thermal power plants near urban areas usually use high-parameter steam for power generation and low-parameter steam for heating, so that heat can be fully utilized, which not only improves social benefits but also improves the economic benefits of thermal power plants. At present, most of the makeup water in the heating pipe network system directly uses municipal tap water, and a small number use softened water. The corrosion of carbon steel pipes in the system is relatively common.

[0003] Due to the presence of trace impurity elements, surface inclusions or surface defects in carbon steel, the electrode potentials of various parts of the metal surface are not equal. In an oxygen-containing neutral aqueous solution, many micro-cells can be formed on the surface. The part with a higher potential is the local cathode, and the part with a lower potential is the local anode. Since the cathode potential is higher than the anode potential, the electrons generated by the anodic reaction must flow from the anode region to the cathode region through the metal matrix and be consumed by the oxygen reduction reaction on the surface of the cathode region. At the same time, cations (Fe 2+ ) migrate to the cathode, and anions (OH - ) migrate to the anode, thus forming a current loop and enabling the corrosion process to continue. The mechanism of oxygen corrosion of carbon steel is as follows:

[0004] Anodic reaction: Fe → Fe 2+ + 2e - ;

[0005] Cathodic reaction: O 2 + H 2 O + 4e - → 4OH - ;

[0006] Secondary reaction:

[0007]

[0008] Fe(OH) 2 + O 2 + H 2 O → Fe(OH) 3 ;

[0009] Fe(OH) 3 → γ-FeOOH + H 2 O;

[0010] γ-FeOOH + Fe + H 2 O → Fe 3 O4 +Fe 3+ +OH - ;

[0011] At present, the common anti-corrosion methods for heat supply networks mainly involve adding corrosion inhibitors. However, due to the large amount of water retained in the heat supply network system, the total amount of chemicals to be added is also very large, resulting in high costs. Moreover, some chemicals are toxic and may pose hazards to the human body. From the mechanism of oxygen corrosion of carbon steel, it can be seen that the electron acceptor for the corrosion of carbon steel pipes in the heat supply network system is oxygen. Although the current heat supply network system is a closed system, there is generally no deaeration measure for its makeup water. Therefore, the dissolved oxygen in the makeup water of the heat supply network is basically in a saturated state, introducing a large amount of dissolved oxygen into the heat supply network circulating water. If the oxygen in the heat supply network circulating water can be removed, the corrosion rate of carbon steel in the heat supply network system can be significantly reduced. The common deaeration methods mainly include thermal deaeration and chemical deaeration. Among them, thermal deaeration is to heat the water to the saturated temperature at the corresponding pressure (usually reaching the boiling point), so that the oxygen and other dissolved gases in the water escape due to the decrease in partial pressure. Due to the large volume of the heat supply network circulating water, the energy consumption of applying thermal deaeration to the heat supply network system is relatively high; chemical deaeration is to add chemical agents to react with the oxygen in the water, thereby consuming oxygen. Common chemicals used for deaeration include hydrazine, sodium sulfite, etc. However, hydrazine is toxic and volatile and has basically been phased out, while sodium sulfite has problems such as difficult control of the dosing amount and unstable deaeration effect. Summary of the Invention

[0012] In view of the problems existing in the prior art, the present invention provides a device and method for deaerating heat supply network circulating water, which uses a membrane method to remove the oxygen in the heat supply network circulating water, and can significantly reduce the corrosion rate of carbon steel pipes in the heat supply network system without adding chemicals.

[0013] To solve the above technical problems, the present invention is achieved through the following technical solutions:

[0014] According to the first aspect of the present invention, there is provided a device for deaerating heat supply network circulating water, including a water-oxygen separation membrane module. The water-oxygen separation membrane module includes a shell and a water-oxygen separation membrane disposed inside the shell. The water-oxygen separation membrane divides the shell into a liquid phase side and a gas phase side. The liquid phase side is provided with a liquid phase side inlet and a liquid phase side outlet, and the gas phase side is provided with a gas phase side outlet; the liquid phase side inlet is connected to a heat supply network circulating water supply pump, the inlet of the heat supply network circulating water supply pump is connected to the heat supply network system, and the liquid phase side outlet is connected to the heat supply network system; the gas phase side outlet is connected to a vacuum pump, and the vacuum pump is used to evacuate the gas phase side to form an oxygen concentration difference.

[0015] In a possible implementation of the first aspect, the heat network circulating water deaeration device further includes a pre-filter disposed between the water-oxygen separation membrane module and the heat network circulating water supply pump. The outlet of the heat network circulating water supply pump is connected to the inlet of the pre-filter, and the outlet of the pre-filter is connected to the liquid-phase side inlet.

[0016] In a possible implementation of the first aspect, the heat network circulating water deaeration device further includes a de-ironing device disposed between the pre-filter and the heat network circulating water supply pump. The outlet of the heat network circulating water supply pump is connected to the inlet of the de-ironing device, and the outlet of the de-ironing device is connected to the inlet of the pre-filter.

[0017] In a possible implementation of the first aspect, the water-oxygen separation membrane module is a multi-stage series structure. The liquid-phase side inlet of the first-stage water-oxygen separation membrane module is connected to the outlet of the pre-filter, and the liquid-phase side outlet of the last-stage water-oxygen separation membrane module is connected to the heat network system.

[0018] In a possible implementation of the first aspect, the heat network circulating water deaeration device further includes a gas-liquid separator connected to the vacuum pump.

[0019] In a possible implementation of the first aspect, the inlet of the heat network circulating water supply pump is connected to the return water pipeline of the heat network system.

[0020] In a possible implementation of the first aspect, the inlet of the heat network circulating water supply pump is further connected to the make-up water pipeline of the heat network system.

[0021] In a possible implementation of the first aspect, the heat network circulating water deaeration device further includes a nitrogen purging system. The gas phase side is provided with a nitrogen inlet, and the nitrogen inlet is connected to the nitrogen purging system.

[0022] In a possible implementation of the first aspect, the water-oxygen separation membrane adopts a hollow fiber hydrophobic microporous membrane.

[0023] According to the second aspect of the present invention, there is provided a method for deaerating heat network circulating water, using the heat network circulating water deaeration device described above. The method includes:

[0024] Using the heat network circulating water supply pump to input the heat network circulating water of the heat network system from the liquid-phase side inlet into the liquid phase side, using the vacuum pump to evacuate the gas phase side to form an oxygen concentration difference, driving the dissolved oxygen in the heat network circulating water on the liquid phase side to cross the water-oxygen separation membrane and enter the gas phase side, and being pumped out from the gas phase side outlet.

[0025] Compared with the prior art, the present invention has at least the following beneficial effects:

[0026] An apparatus for deaerating heat network circulating water provided by the present invention uses a heat network circulating water supply pump to input the heat network circulating water of the heat network system from the liquid phase side inlet into the liquid phase side, uses a vacuum pump to evacuate the gas phase side to form an oxygen concentration difference, drives the dissolved oxygen in the heat network circulating water on the liquid phase side to cross the water-oxygen separation membrane and enter the gas phase side, and is removed from the gas phase side outlet. It can be seen that by adopting a water-oxygen separation membrane module and using membrane deaeration technology, the dissolved oxygen in the heat network circulating water can be efficiently removed. The selective permeability of the water-oxygen separation membrane enables the oxygen in the water to cross the membrane and enter the gas phase side under the drive of the oxygen concentration difference, and is evacuated by the vacuum pump, thereby greatly reducing the corrosion rate of carbon steel pipelines in the heat network system. Compared with the traditional method of adding corrosion inhibitors, the present invention does not require the addition of any chemical agents, avoiding the chemical agent cost and the possible environmental pollution and human health risks. The membrane deaeration technology adopted by the present invention, compared with thermal deaeration, does not require heating the water to the boiling point, greatly reducing the energy consumption, and conforming to the environmental protection concept of energy conservation and emission reduction. At the same time, since deaeration does not rely on chemical agents, the energy consumption and carbon emissions during the production, transportation and use of chemical agents are avoided.

[0027] To make the above objects, features and advantages of the present invention more obvious and understandable, the following specifically enumerates preferred embodiments and, in conjunction with the accompanying drawings, the detailed description is as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the specific embodiments of the present invention, the following will briefly introduce the drawings required for use in the description of the specific embodiments. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0029] Figure 1 It is a schematic diagram of an apparatus for deaerating heat network circulating water according to the present invention in one embodiment;

[0030] Figure 2 It is a schematic diagram of an apparatus for deaerating heat network circulating water according to the present invention in another embodiment.

[0031] In the figure: 1 - water-oxygen separation membrane module; 101 - liquid phase side inlet; 102 - liquid phase side outlet; 103 - gas phase side outlet; 104 - nitrogen inlet; 2 - heat network circulating water supply pump; 3 - vacuum pump; 4 - pre-filter; 5 - iron remover; 6 - gas-water separator; 7 - return water pipeline; 8 - make-up water pipeline. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0033] As Figure 1 shown, an embodiment of the present invention provides a device for deaerating the circulating water of a heat network, mainly for efficiently and safely removing the dissolved oxygen in the circulating water of the heat network. The device includes a water-oxygen separation membrane module 1, which includes a shell and a water-oxygen separation membrane disposed inside the shell. The water-oxygen separation membrane divides the shell into a liquid phase side and a gas phase side. The liquid phase side is provided with a liquid phase side inlet 101 and a liquid phase side outlet 102, and the gas phase side is provided with a gas phase side outlet 103. The liquid phase side inlet 101 is connected to a heat network circulating water supply pump 2, the inlet of the heat network circulating water supply pump 2 is connected to the heat network system, and the liquid phase side outlet 102 is connected to the heat network system. The gas phase side outlet 103 is connected to a vacuum pump 3, and the vacuum pump 3 is used to evacuate the gas phase side to form an oxygen concentration difference.

[0034] Specifically, the water-oxygen separation membrane module 1 is composed of a shell and a water-oxygen separation membrane. The interior of the shell is divided into two independent spaces - the liquid phase side and the gas phase side by the water-oxygen separation membrane. The water-oxygen separation membrane has high selective permeability and can effectively separate the dissolved oxygen in water from water molecules, ensuring the efficient transfer of oxygen to the gas phase side. The liquid phase side is provided with a liquid phase side inlet 101 and a liquid phase side outlet 102, which are responsible for the entry of the heat network circulating water and the return of the treated water respectively. The liquid phase side inlet 101 is directly connected to the heat network circulating water supply pump 2 to ensure the stable supply of circulating water under pressure; the liquid phase side outlet 102 is then connected back to the heat network system to ensure that the deaerated water body directly participates in the heat network circulation. The gas phase side is provided with a gas phase side outlet 103, which is the outlet where oxygen is evacuated from the system. This outlet is connected to the vacuum pump 3, and through the operation of the vacuum pump, the low-pressure state of the gas phase side is maintained, forming an oxygen concentration difference with the liquid phase side to provide power for driving the transmembrane migration of dissolved oxygen. The heat network circulating water supply pump 2, as the power source of the entire deaeration process, is responsible for extracting the circulating water to be treated from the heat network system and sending it into the liquid phase side of the water-oxygen separation membrane module through the liquid phase side inlet 101. The vacuum pump 3 is installed after the gas phase side outlet 103 and is responsible for evacuating the gas phase side to maintain a low-oxygen or oxygen-free environment.

[0035] In this embodiment, the method for deaerating the circulating water of the heat network using the above device is as follows:

[0036] First, start the heat network circulating water supply pump 2. Use the pressure generated by it to send the circulating water in the heat network system into the liquid phase side of the water-oxygen separation membrane module 1 through the liquid phase side inlet 101. At this time, the circulating water flows inside the membrane module, preparing for deaeration treatment. Subsequently, start the vacuum pump 3 to perform a vacuum pumping operation on the gas phase side. As the pressure on the gas phase side gradually decreases, an oxygen concentration difference is formed between the gas phase side and the liquid phase side. The concentration gradient becomes the main driving force for driving the dissolved oxygen to migrate from the liquid phase side (high concentration) to the gas phase side (low concentration). The dissolved oxygen is effectively separated during the transmembrane migration process and accumulates on the gas phase side. The oxygen accumulated on the gas phase side is evacuated from the system through the gas phase side outlet 103 with the continuous operation of the vacuum pump, and finally discharged to the external environment or further processed. The deaerated circulating water flows out from the liquid phase side outlet 102 and returns to the heat network system through the connecting pipeline to continue participating in the heating cycle. At this time, the dissolved oxygen content in the circulating water has decreased, effectively slowing down the corrosion rate of the carbon steel pipeline in the heat network system.

[0037] In one realizable manner, as Figure 1 shown, the heat network circulating water deaeration device further includes a pre-filter 4 provided between the water-oxygen separation membrane module 1 and the heat network circulating water supply pump 2. The outlet of the heat network circulating water supply pump 2 is connected to the inlet of the pre-filter 4, and the outlet of the pre-filter 4 is connected to the liquid phase side inlet 101.

[0038] Specifically, the pre-filter 4 is located between the heat network circulating water supply pump 2 and the water-oxygen separation membrane module 1. The main function of the pre-filter 4 is to remove substances such as suspended solids, colloids, and corrosion products in the water to reduce the turbidity of the heat network circulating water. Through the pretreatment operation, it can be ensured that the condensate water entering the membrane module has removed substances such as suspended solids, colloids, and corrosion products, thereby avoiding damage to the water-oxygen separation membrane module 1 itself caused by particulate matter and extending its service life.

[0039] It should be noted that the filter material of the pre-filter 4 can be selected according to actual needs, such as polypropylene, PP cotton, activated carbon, etc.

[0040] In this embodiment, the method for deaerating the heat network circulating water using the above device is as follows:

[0041] First, start the heat network circulating water supply pump 2, use the pressure generated by it to extract the circulating water in the heat network system, and send it into the pre-filter 4 through the pipeline for pretreatment. The circulating water passes through the filter material in the pre-filter 4, removing substances such as suspended solids, colloids, and corrosion products in the water, thereby reducing the turbidity of the water. The pretreated circulating water flows out from the outlet of the pre-filter 4, is connected to the liquid-phase side inlet 101 of the water-oxygen separation membrane module 1 through the pipeline, and enters the water-oxygen separation membrane module 1 for deoxygenation treatment. Start the vacuum pump 3, perform a vacuum pumping operation on the gas phase side, and form an oxygen concentration difference with the liquid phase side. Driven by the concentration gradient, dissolved oxygen migrates across the membrane from the liquid phase side to the gas phase side and accumulates on the gas phase side. The oxygen accumulated on the gas phase side is continuously pumped out of the system through the gas phase side outlet 103 with the continuous operation of the vacuum pump, and finally discharged to the external environment or further processed. The circulating water after deoxygenation treatment flows out from the liquid phase side outlet 102, returns to the heat network system through the connecting pipeline, and continues to participate in the heating cycle.

[0042] In an implementable manner, as Figure 2 shown, the heat network circulating water deoxygenation device further includes a de-ironing device 5 provided between the pre-filter 4 and the heat network circulating water supply pump 2. The outlet of the heat network circulating water supply pump 2 is connected to the inlet of the de-ironing device 5, and the outlet of the de-ironing device 5 is connected to the inlet of the pre-filter 4.

[0043] Specifically, the de-ironing device 5 is located between the heat network circulating water supply pump 2 and the pre-filter 4. Exemplarily, the de-ironing device 5 adopts strong magnetic technology and can effectively remove ferromagnetic corrosion products in the water, such as rust, iron ions, etc. Through pretreatment, the iron content of the circulating water can be reduced, thereby reducing the turbidity of the water, reducing the damage to the water-oxygen separation membrane module 1 and the pre-filter 4, and extending their service life.

[0044] In this embodiment, the method for deoxygenating the heat network circulating water using the above device is as follows:

[0045] First, start the heat network circulating water supply pump 2. Use the pressure generated by it to extract the circulating water in the heat network system and send it through a pipeline to the iron remover 5 for iron removal treatment. The circulating water passes through the attraction of a strong magnetic field in the iron remover 5 to remove ferromagnetic corrosion products in the water, such as rust, iron ions, etc. The iron-removed circulating water flows out from the outlet of the iron remover 5 and is connected to the inlet of the pre-filter 4 through a pipeline for further pretreatment. The circulating water passes through the filtering action of the filter media in the pre-filter 4 to remove suspended solids, non-ferromagnetic colloids and other impurities in the water, thereby reducing the turbidity of the water. The pretreated circulating water flows out from the outlet of the pre-filter 4 and is connected to the liquid-phase side inlet 101 of the water-oxygen separation membrane module 1 through a pipeline and enters the inside of the membrane module for deoxygenation treatment. Start the vacuum pump 3 to perform a vacuum pumping operation on the gas phase side to form an oxygen concentration difference between the gas phase side and the liquid phase side. Driven by the concentration gradient, dissolved oxygen migrates across the membrane from the liquid phase side to the gas phase side and accumulates on the gas phase side. The oxygen accumulated on the gas phase side is evacuated from the system through the gas phase side outlet 103 with the continuous operation of the vacuum pump and is finally discharged to the external environment or further processed. The circulating water after deoxygenation treatment flows out from the liquid phase side outlet 102 and returns to the heat network system through a connecting pipeline to continue participating in the heating cycle.

[0046] In an implementable manner, as Figure 1 shown in FIG. 2, the water-oxygen separation membrane module 1 has a multi-stage series structure. The liquid-phase side inlet 101 of the first-stage water-oxygen separation membrane module 1 is connected to the outlet of the pre-filter 4, and the liquid-phase side outlet 102 of the last-stage water-oxygen separation membrane module 1 is connected to the heat network system.

[0047] That is to say, the multi-stage series design can gradually reduce the dissolved oxygen content in the water to ensure that the dissolved oxygen in the circulating water produced by the last-stage water-oxygen separation membrane module 1 reaches the required level.

[0048] In an implementable manner, as Figure 1 shown in FIG. 2, the heat network circulating water deoxygenation device further includes a gas-liquid separator 6 connected to the vacuum pump 3. The gas-liquid separator 6 is used to separate the gas extracted from the gas phase side of the membrane module and the trace moisture that may be entrained. The gas-liquid separator 6 ensures that the moisture in the gas is effectively removed, and the separated dry gas can be discharged to the external environment or further processed.

[0049] In an implementable manner, as Figure 1As shown in Fig. 1 or 2, the inlet of the heat network circulating water supply pump 2 is connected to the return water pipeline 7 of the heat network system. Specifically, the inlet of the heat network circulating water supply pump 2 is directly connected to the return water pipeline 7 of the heat network system, and is responsible for extracting the cooled circulating water from the return water pipeline. The return water pipeline 7 of the heat network system serves as the water inlet source of the heat network circulating water deaeration device. This pipeline is responsible for transporting the heat network circulating water that has completed heat exchange at the user's end and has a reduced temperature to the device. By selecting the cooled circulating water as the inlet water, it can effectively prevent the water oxygen separation membrane module 1 from being damaged due to excessive temperature and extend the service life of the membrane module.

[0050] In an implementable manner, as Figure 1 shown in Fig. 1 or 2, the inlet of the heat network circulating water supply pump 2 is also connected to the make-up water pipeline 8 of the heat network system. Specifically, the make-up water pipeline 8 of the heat network system serves as the make-up water source for the heat network circulating water and is responsible for replenishing water to the heat network system. Since the oxygen in the heat network system mainly comes from the make-up water, a pipeline for treating the make-up water is provided to ensure that the make-up water has been deaerated before entering the heat network system. The inlet of the heat network circulating water supply pump 2 is connected to both the return water pipeline 7 and the make-up water pipeline 8 of the heat network system. Under normal circumstances, the heat network circulating water supply pump 2 mainly extracts the cooled circulating water from the return water pipeline 7 for treatment; when water replenishment is required, the regulating valve is adjusted to allow part or all of the make-up water to enter the treatment process through the heat network circulating water supply pump 2.

[0051] In an implementable manner, as Figure 1 shown in Fig. 1 or 2, the heat network circulating water deaeration device further includes a nitrogen purging system. A nitrogen inlet 104 is provided on the gas phase side, and the nitrogen inlet 104 is connected to the nitrogen purging system.

[0052] To elaborate, the nitrogen inlet 104 communicates with the nitrogen source. Nitrogen is introduced into one end of the gas phase side of the water oxygen separation membrane module 1, and the other end is connected to the inlet of the vacuum pump. Nitrogen flows through the water oxygen separation membrane module 1 in a cross-flow manner with the heat network circulating water, that is, nitrogen flows on the gas phase side while the heat network circulating water flows on the liquid phase side. After nitrogen enters the gas phase side of the membrane module, it can dilute the oxygen that crosses the membrane from the heat network circulating water side to the vacuum side, reducing the oxygen concentration on the gas phase side, thereby increasing the oxygen concentration difference across the membrane. When nitrogen flows on the gas phase side, it can promptly carry away the oxygen that crosses the membrane from the heat network circulating water side to the vacuum side, preventing oxygen from accumulating on the gas phase side. In this way, the driving force for oxygen to enter the gas phase side from the liquid phase side can be further increased, improving the deaeration efficiency.

[0053] In one realizable manner, the water-oxygen separation membrane adopts a hollow fiber hydrophobic microporous membrane. The hollow fiber hydrophobic microporous membrane is made of a polymer non-polar material, such as polytetrafluoroethylene (PTFE) or polyvinylidene fluoride (PVDF), etc. These materials have extremely strong hydrophobicity, making it difficult for water molecules to pass through their microporous structure, while gas molecules can smoothly pass through under the drive of the concentration difference. The hollow fiber membrane has a unique hollow structure, which not only increases the membrane area and improves the permeation efficiency of gas molecules, but also enables the membrane module to maintain a relatively low pressure drop during operation, reducing energy consumption.

[0054] As Figure 1 shown, in one embodiment, for a heat network circulating water system with a relatively high dissolved oxygen content (dissolved oxygen above 3000 μg / L), a pipeline for supplementing heat network water to this embodiment is provided, and the heat network makeup water can be treated simultaneously. The heat network circulating water that has been heat-exchanged and cooled at the user and the heat network makeup water are connected to the inlet of the heat network circulating water supply pump 2 of this embodiment through a pipeline. The outlet of the heat network circulating water supply pump 2 is connected to the inlet of the pre-filter 4. The outlet of the pre-filter 4 is connected to the liquid-phase side inlet 101 of the primary water-oxygen separation membrane module 1. Its liquid-phase side outlet 102 is connected to the liquid-phase side inlet 101 of the next-stage water-oxygen separation membrane module 1. The liquid-phase side outlet 102 of the final-stage water-oxygen separation membrane module 1 is connected to the heat network system. The gas-phase side outlet 103 of the water-oxygen separation membrane module 1 is connected to the inlet of the vacuum pump 3. The outlet of the vacuum pump 3 is connected to the inlet of the gas-liquid separator 6. The exhaust gas of the gas-liquid separator 6 is directly discharged to the atmosphere.

[0055] The operation method of the device in this embodiment is as follows:

[0056] The heat network circulating water and the heat network makeup water are pressurized by the heat network circulating water supply pump 2 and then introduced into the pre-filter 4. Substances such as suspended solids, colloids, and corrosion products in the water are removed. The water discharged from the pre-filter 4 enters the liquid-phase side inlet 101 of the primary water-oxygen separation membrane module 1. After being treated by the multi-stage series water-oxygen separation membrane module 1, it returns to the heat network system through the liquid-phase side outlet 102 of the final-stage water-oxygen separation membrane module 1. The gas-phase side of the water-oxygen separation membrane module 1 is subjected to vacuum pumping. The oxygen in the liquid-phase side heat network circulating water enters the gas-phase side across the membrane under the drive of the concentration difference between the two sides of the membrane and is pumped away by the vacuum pump 3 and enters the gas-liquid separator 6. The extracted gas is discharged to the atmosphere. The separated water can be reused in systems such as the power plant industrial water system that have no requirements for oxygen content.

[0057] In this embodiment, a three - stage series water - oxygen separation membrane module 1 is provided. The material of the water - oxygen separation membrane is polytetrafluoroethylene (PTFE). The outer diameter of its membrane filaments is 300 μm, and the inner diameter is 200 μm. The filler of the pre - filter 4 is a polypropylene filter element. The vacuum pump 3 is a water - ring type, and the vacuum degree at the gas - phase side outlet is controlled to be - 120~ - 150 kPa. In this embodiment, the dissolved oxygen content of the heat - network circulating water entering the liquid - phase side inlet of the first - stage water - oxygen separation membrane module 1 is 3500~4000 μg / L. After treatment, the dissolved oxygen content of the water returned to the heat - network system from the liquid - phase side outlet of the last - stage water - oxygen separation membrane module 1 can be reduced to less than 500 μg / L.

[0058] As Figure 2 shown, in another embodiment, it is applicable to a heat - network circulating water system with a relatively low dissolved oxygen content (dissolved oxygen below 3000 μg / L). In addition, a strong magnetic iron remover is installed in this embodiment to remove ferromagnetic corrosion products in the heat - network circulating water. On the one hand, it can ensure the inlet turbidity of the water - oxygen separation membrane module 1, and on the other hand, it can extend the service life of the water - oxygen separation membrane module 1 and the pre - filter 4. The heat - network circulating water that has been cooled by heat exchange at the user's side and the heat - network make - up water are connected to the inlet of the heat - network circulating water supply pump 2 of this embodiment through pipelines. The outlet of the heat - network circulating water supply pump 2 is connected to the inlet of the strong magnetic iron remover. The outlet of the strong magnetic iron remover is connected to the inlet of the pre - filter 4. The outlet of the pre - filter 4 is connected to the liquid - phase side inlet 101 of the first - stage water - oxygen separation membrane module 1. Its liquid - phase side outlet 102 is connected to the liquid - phase side inlet 101 of the next - stage water - oxygen separation membrane module 1. The liquid - phase side outlet 102 of the last - stage water - oxygen separation membrane module 1 is connected to the heat - network system. The nitrogen inlet 104 of the water - oxygen separation membrane module 1 near the liquid - phase side outlet is connected to a nitrogen source. The gas - phase side outlet 103 near the liquid - phase side inlet 101 is connected to the inlet of the vacuum pump 3, so that nitrogen purging and heat - network circulating water enter and pass through the membrane module in a cross - flow form. The outlet of the vacuum pump 3 is connected to the inlet of the gas - water separator 6, and the exhaust gas of the gas - water separator 6 is directly discharged to the atmosphere.

[0059] The operation method of the device in this embodiment is as follows:

[0060] The hot water network circulating water and the make-up water for the hot water network are boosted by the hot water network circulating water supply pump 2 and then introduced into the high-intensity magnetic separator to remove ferromagnetic corrosion products in the hot water network circulating water. After being further treated by the pre-filter 4, substances such as suspended solids, colloids, and corrosion products in the water are removed, and then it enters the liquid-phase side inlet 101 of the first-stage water-oxygen separation membrane module 1. After being treated by the multi-stage series water-oxygen separation membrane module 1, it returns to the hot water network system from the liquid-phase side outlet 102 of the last-stage water-oxygen separation membrane module 1. Nitrogen is introduced into the nitrogen inlet 104 near the liquid-phase side outlet of each stage of the water-oxygen separation membrane module 1, and a vacuum pump 3 is used to perform vacuum pumping at the gas-phase side outlet 103 near the liquid-phase side inlet 101 of each stage of the water-oxygen separation membrane module 1, so that nitrogen purging and the hot water network circulating water enter the water-oxygen separation membrane module 1 in a cross-flow form. Oxygen in the liquid-phase side hot water network circulating water crosses the membrane and enters the gas-phase side under the drive of the concentration difference across the membrane and is pumped away by the vacuum pump 3 and enters the gas-water separator 6. The extracted gas is discharged to the atmosphere, and the separated water can be reused in systems such as the power plant industrial water system that have no requirements for dissolved oxygen content.

[0061] In this embodiment, a total of three-stage series water-oxygen separation membrane modules 1 are provided. The water-oxygen separation membrane is made of polytetrafluoroethylene (PTFE), with an outer diameter of the membrane filaments of 300 μm and an inner diameter of 200 μm; the high-intensity magnetic separator is made of neodymium magnet high-intensity magnetic material; the filler of the pre-filter 4 is a polypropylene filter element; the vacuum pump 3 is a water-ring type, and the vacuum degree at the gas-phase side outlet of the membrane module is controlled to be -92 to -96 kPa; in this embodiment, the dissolved oxygen content of the hot water network circulating water entering the liquid-phase side inlet of the first-stage water-oxygen separation membrane module 1 is 500 to 1000 μg / L. After treatment, the dissolved oxygen content of the water returning to the hot water network system from the liquid-phase side outlet of the last-stage water-oxygen separation membrane module 1 can be reduced to less than 20 μg / L.

[0062] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0063] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, "a plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0064] In the present invention, unless otherwise clearly specified or limited, terms such as "connected" and "coupled" shall be construed in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral one; it may be a mechanical connection, an electrical connection, or capable of communicating with each other; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0065] In the present invention, unless otherwise clearly specified or limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "beneath" and "underneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the horizontal height of the first feature is less than that of the second feature.

[0066] In the present invention, terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0067] Finally, it should be noted that the above-described embodiments are only specific embodiments of the present invention, used to illustrate the technical solutions of the present invention, rather than limiting it. The protection scope of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: any person skilled in the art within the technical scope disclosed by the present invention can still modify the technical solutions recorded in the foregoing embodiments, or can easily think of changes, or make equivalent replacements for some of the technical features; and these modifications, changes 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 invention, and should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A device for deoxygenating circulating water in a heat network, characterized in that: The invention comprises a water-oxygen separation membrane assembly (1), wherein the water-oxygen separation membrane assembly (1) comprises a tube shell and a water-oxygen separation membrane arranged in the tube shell, wherein the water-oxygen separation membrane separates the tube shell into a liquid phase side and a gas phase side, wherein the liquid phase side is provided with a liquid phase side inlet (101) and a liquid phase side outlet (102), and wherein the gas phase side is provided with a gas phase side outlet (103); the liquid phase side inlet (101) is connected to a heat network circulating water supply pump (2), wherein the inlet of the heat network circulating water supply pump (2) is connected to a heat network system, and the liquid phase side outlet (102) is connected to the heat network system; and the gas phase side outlet (103) is connected to a vacuum pump (3), wherein the vacuum pump (3) is used to evacuate the gas phase side to form an oxygen concentration difference.

2. The device for deoxygenating circulating water in a heating network according to claim 1, characterized in that: The heat network circulating water deoxygenation device also includes a pre-filter (4) arranged between the water-oxygen separation membrane assembly (1) and the heat network circulating water supply pump (2), the outlet of the heat network circulating water supply pump (2) is connected to the inlet of the pre-filter (4), and the outlet of the pre-filter (4) is connected to the liquid phase side inlet (101).

3. The device for deoxygenating circulating water in a heating network according to claim 2, characterized in that: The heating network circulating water deoxygenation device also includes an iron remover (5) arranged between the pre-filter (4) and the heating network circulating water supply pump (2), the outlet of the heating network circulating water supply pump (2) is connected to the inlet of the iron remover (5), and the outlet of the iron remover (5) is connected to the inlet of the pre-filter (4).

4. The device for deoxygenating circulating water in a heating network according to claim 3, characterized in that: The water-oxygen separation membrane assembly (1) is a multi-stage series structure, the liquid phase side inlet (101) of the first-stage water-oxygen separation membrane assembly (1) is connected to the outlet of the pre-filter (4), and the liquid phase side outlet (102) of the last-stage water-oxygen separation membrane assembly (1) is connected to the heat network system.

5. The device for deoxygenating circulating water in a heating network according to claim 1, characterized in that: The heat network circulating water deoxygenation device also includes a gas-water separator (6) connected to the vacuum pump (3).

6. The device for deoxygenating circulating water in a heating network according to claim 1, characterized in that: The inlet of the heating network circulating water supply pump (2) is connected to the return water pipeline (7) of the heating network system.

7. The device for deoxygenating circulating water in a heating network according to claim 6, characterized in that: The inlet of the heating network circulating water supply pump (2) is also connected to the water replenishment pipeline (8) of the heating network system.

8. The device for deoxygenating circulating water in a heating network according to claim 1, characterized in that: The heat network circulating water deoxygenation device also includes a nitrogen purge system. The gas phase side is provided with a nitrogen inlet (104), and the nitrogen inlet (104) is connected to the nitrogen purge system.

9. The device for deoxygenating circulating water in a heating network according to claim 1, characterized in that: The water-oxygen separation membrane adopts a hollow fiber hydrophobic microporous membrane.

10. A method for deoxygenating circulating water in a heat network, characterized in that: A device for deoxygenating circulating water in a heat network according to any one of claims 1 to 9 is used, and the method comprises: The heat network circulating water supply pump (2) is used to input the heat network circulating water of the heat network system from the liquid phase side inlet (101) to the liquid phase side, and the vacuum pump (3) is used to evacuate the gas phase side to form an oxygen concentration difference, driving the dissolved oxygen in the heat network circulating water on the liquid phase side to cross the water-oxygen separation membrane into the gas phase side and be extracted from the gas phase side outlet (103).

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