SCAL type indirect cooling circulating water bypass purification device and method

Abstract

The invention discloses an SCAL type intercooling circulating water bypass purification device and method, and the device comprises a pretreatment module which comprises a water feeding pump and a security filter, and the water feeding pump is used for pumping intercooling circulating water cooled by an intercooling tower and conveying the intercooling circulating water to an inlet of the security filter; the desalting module comprises an electric desalting device and an electric desalting water producing tank, an inlet of the electric desalting device is connected with an outlet of the security filter, and an inlet of the electric desalting water producing tank is connected with a fresh water outlet of the electric desalting device; the deoxidization module comprises a degassing membrane booster pump, a degassing membrane assembly and a vacuum pump, an inlet of the degassing membrane booster pump is connected with an outlet of the electrodeionization water production tank, an outlet of the degassing membrane booster pump is connected to a liquid phase side inlet of the degassing membrane assembly, and a liquid phase side outlet of the degassing membrane assembly is connected to the SCAL type indirect air cooling system; an inlet of the vacuum pump is connected with a gas phase side outlet, close to the liquid phase side inlet, of the degassing membrane assembly. The corrosion rate of carbon steel and pure aluminum in the SCAL type indirect air cooling 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 SCAL type indirect cooling circulating water bypass purification device and method. Background Art

[0002] The SCAL type indirect air cooling system has the advantages of water conservation, small floor area of the indirect cooling tower, and can meet the requirements of unit large-scaleization, etc., and is mainly applied to newly-built thermal power units in the northern coal-rich and water-scarce areas. The circulating water cooling water system of this unit is not designed with water quality purification equipment. After most of the systems are put into production, water quality anomalies such as high conductivity, increased pH, and increased iron content of the circulating water occur for unknown reasons, leading to uniform corrosion of carbon steel and pure aluminum in the system and erosion corrosion at the pipe orifice of the aluminum pipe. Since the pure aluminum in the system is an amphoteric metal and has a large chemical property difference from carbon steel, the traditional anti-corrosion methods of increasing the pH value or only adding carbon steel corrosion inhibitors are no longer applicable.

[0003] The corrosion mechanism of carbon steel in the SCAL type indirect air cooling system 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 O 4 + Fe 3+ + OH - ;

[0011] The corrosion mechanism of pure aluminum in the SCAL type indirect air cooling system is as follows:

[0012] From the perspective of electrochemical properties, aluminum is a very active and corrosion - prone metal. However, it is quite stable at room temperature. The main reason is that aluminum can form a dense aluminum oxide film on its surface in air or in an aqueous solution with a pH of 4.5 - 8.5, which leads to passivation and prevents further corrosion of aluminum. Therefore, it is stable in air and water at room temperature. However, aluminum is an amphoteric metal, and in acidic - biased and alkaline - biased environments, the oxide film is easily dissolved, accelerating corrosion. The corrosion mechanism of aluminum in alkaline solution is:

[0013] Al 2 O 3 +2OH - =2AlO 2 - +H 2 O

[0014] Al+4OH - →Al(OH) 4 - +3e -

[0015] In addition, when the solution contains relatively high concentrations of halide ions such as F - 、Cl - etc., aluminum is prone to pitting corrosion:

[0016] Al(OH) 3 +3Cl - →AlCl 3 +3OH -

[0017] Currently, the common anti - corrosion method for the SCAL - type indirect air - cooling system is mainly to add corrosion inhibitors. However, due to the large water inventory in the indirect cooling system, the total amount of chemicals to be added is also very large, resulting in high costs. Moreover, some chemicals are toxic and may cause harm to the human body. According to 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 SCAL - type indirect air - cooling system is oxygen. Although the SCAL - type indirect air - cooling system is a closed system currently, there is generally no de - oxygenation measure for its makeup water. Therefore, the dissolved oxygen in the makeup water of the SCAL - type indirect air - cooling system is basically in a saturated state, introducing a large amount of dissolved oxygen into the indirect cooling circulating water. If the oxygen in the indirect cooling circulating water can be removed, the corrosion of carbon steel in the SCAL - type indirect air - cooling system can be significantly reduced. For the corrosion of pure aluminum in the SCAL - type indirect air - cooling system, on the one hand, it is necessary to maintain the indirect cooling circulating water in a neutral water quality condition to avoid alkaline or acidic corrosion of pure aluminum. On the other hand, it is necessary to remove corrosive ions such as F - 、Cl - etc. in the indirect cooling circulating water to avoid pitting corrosion of pure aluminum. After investigation, there is currently no device or method that can simultaneously remove dissolved oxygen and corrosive impurity ions in the SCAL - type indirect cooling circulating water. Summary of the Invention

[0018] In view of the problems existing in the prior art, the present invention provides a bypass purification device and method for SCAL type indirect cooling circulating water, which uses a multi-stage degassing membrane to remove oxygen in the indirect cooling circulating water and couples electrodeionization to remove corrosive ions in the indirect cooling circulating water, and can greatly reduce the corrosion rates of carbon steel and pure aluminum in the SCAL type indirect air cooling system without adding chemicals.

[0019] In order to solve the above technical problems, the present invention is realized through the following technical solutions:

[0020] According to a first aspect of the present invention, there is provided a bypass purification device for SCAL type indirect cooling circulating water, comprising:

[0021] A pretreatment module, including a feed water pump and a security filter, the feed water pump is used to extract the indirect cooling circulating water cooled by the indirect cooling tower and transport it to the inlet of the security filter;

[0022] A desalination module, including an electrodeionization device and an electrodeionization product water tank, the inlet of the electrodeionization device is connected to the outlet of the security filter, and the inlet of the electrodeionization product water tank is connected to the fresh water outlet of the electrodeionization device;

[0023] An deoxidation module, including a degassing membrane booster pump, a degassing membrane assembly and a vacuum pump, the inlet of the degassing membrane booster pump is connected to the outlet of the electrodeionization product water tank, the outlet of the degassing membrane booster pump is connected to the liquid phase side inlet of the degassing membrane assembly, and the liquid phase side outlet of the degassing membrane assembly is connected to the SCAL type indirect air cooling system; the inlet of the vacuum pump is connected to the gas phase side outlet of the degassing membrane assembly close to the liquid phase side inlet.

[0024] In a possible implementation manner of the first aspect, the deoxidation module is provided with a multi-stage degassing membrane assembly, the outlet of the degassing membrane booster pump is connected to the liquid phase side inlet of the first-stage degassing membrane assembly, the liquid phase sides of the multi-stage degassing membrane assemblies are connected in series, and the liquid phase side outlet of the last-stage degassing membrane assembly is connected to the SCAL type indirect air cooling system; the inlet of the vacuum pump is connected to the gas phase side outlets of each stage of the degassing membrane assembly close to the liquid phase side inlet.

[0025] In a possible implementation manner of the first aspect, the deoxidation module further includes a nitrogen purging device, and the nitrogen source of the nitrogen purging device is connected to the gas phase side inlet of each stage of the degassing membrane assembly close to the liquid phase side outlet.

[0026] In a possible implementation manner of the first aspect, the deoxidation module further includes a gas-liquid separator, the outlet of the vacuum pump is connected to the inlet of the gas-liquid separator, and the exhaust port of the gas-liquid separator is vented to the atmosphere.

[0027] In a possible implementation manner of the first aspect, the pretreatment module further includes a magnetic separator disposed between the outlet of the feed water pump and the inlet of the security filter, and the magnetic separator is used to remove ferromagnetic corrosion products in the indirect cooling circulating water.

[0028] In a possible implementation manner of the first aspect, the degassing membrane module adopts a shell-and-tube membrane module made of hollow fiber hydrophobic microporous membranes, and the material of the hollow fiber hydrophobic microporous membranes is polytetrafluoroethylene or polyvinylidene fluoride.

[0029] In a possible implementation manner of the first aspect, the concentrated water outlet of the electrodeionization device is connected to the power plant desulfurization system for recovering the concentrated water.

[0030] In a possible implementation manner of the first aspect, the filter material of the security filter is polypropylene or PP cotton, which is used to remove suspended solids, colloids and corrosion products in the indirect cooling circulating water.

[0031] In a possible implementation manner of the first aspect, the treatment device further includes a makeup water treatment pipeline for the indirect cooling system, and the makeup water treatment pipeline is connected to the inlet of the feed water pump for deoxidation and desalination treatment of the makeup water for the indirect cooling system.

[0032] According to the second aspect of the present invention, there is provided a method for purifying the bypass of SCAL type indirect cooling circulating water, using the SCAL type indirect cooling circulating water bypass purification device described above. The method includes:

[0033] Using the feed water pump in the pretreatment module to extract the indirect cooling circulating water cooled down in the indirect cooling tower, and transporting the indirect cooling circulating water to the security filter to remove impurities in the water; the indirect cooling circulating water treated by the security filter is transported to the desalination module, and the electrodeionization device is used to remove impurity ions in the indirect cooling circulating water. The fresh water produced by the electrodeionization device enters the electrodeionization product water tank, and the fresh water in the electrodeionization product water tank is transported to the deoxidation module, and after being boosted by the degassing membrane booster pump, it is transported into the liquid phase side inlet of the degassing membrane module. Vacuum is drawn at the gas phase side outlet near the liquid phase side inlet of the degassing membrane module. Oxygen in the liquid phase side indirect cooling circulating water enters the gas phase side across the membrane driven by the concentration difference on both sides of the membrane and is drawn away by the vacuum pump. The indirect cooling circulating water treated by the degassing membrane module returns to the SCAL type indirect air cooling system from the liquid phase side outlet.

[0034] Compared with the prior art, the present invention has at least the following beneficial effects:

[0035] A SCAL-type indirect cooling circulating water bypass purification device provided by the present invention effectively removes dissolved oxygen in the indirect cooling circulating water through a degassing membrane technology, eliminates the electron acceptor necessary for carbon steel corrosion, and greatly reduces the corrosion rate of carbon steel from the source. At the same time, the coupled electro-deionization technology is used to remove impurity ions in the water, including corrosive ions such as F- and Cl-, avoiding the accelerated corrosion of pure aluminum in a slightly acidic or slightly alkaline environment and the pitting corrosion phenomenon caused by corrosive ions. Traditional methods rely on adding chemical corrosion inhibitors, which not only have high chemical agent costs but also some chemical agents are toxic and may cause harm to the human body and the environment. The present invention does not require adding drugs, avoids the use of chemical agents, and improves the environmental protection benefits. By treating the water quality through physical methods, the safety risks in the procurement, storage, and use of chemical agents are reduced, and the operating costs are lowered. Therefore, the degassing membrane and electro-deionization technologies in the present invention act synergistically to form an efficient and environmentally friendly water quality treatment solution, filling the gap that there is currently no device or method that can simultaneously remove dissolved oxygen and corrosive impurity ions in SCAL-type indirect cooling circulating water.

[0036] 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, makes a detailed description as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] 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 be obtained based on these drawings.

[0038] Figure 1 It is a schematic diagram of a SCAL-type indirect cooling circulating water bypass purification device according to Embodiment 1 of the present invention;

[0039] Figure 2 It is a schematic diagram of a SCAL-type indirect cooling circulating water bypass purification device according to Embodiment 2 of the present invention.

[0040] In the figure: 1 - pretreatment module; 101 - feed water pump; 102 - security filter; 103 - iron remover; 2 - desalination module; 201 - electro-deionization device; 202 - electro-deionization product water tank; 3 - deoxygenation module; 301 - degassing membrane booster pump; 302 - degassing membrane module; 303 - vacuum pump; 304 - gas-water separator. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0041] 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 scope of protection of the present invention.

[0042] As Figure 1 shown, an embodiment of the present invention provides a bypass purification device for SCAL type indirect cooling circulating water, which specifically includes a pretreatment module 1, a desalination module 2 and a deoxygenation module 3. Among them, the pretreatment module 1 includes a feed water pump 101 and a security filter 102. The feed water pump 101 is used to extract the indirect cooling circulating water cooled by the indirect cooling tower and transport it to the inlet of the security filter 102. The desalination module 2 includes an electrodeionization device 201 and an electrodeionization product water tank 202. The inlet of the electrodeionization device 201 is connected to the outlet of the security filter 102, and the inlet of the electrodeionization product water tank 202 is connected to the fresh water outlet of the electrodeionization device 201. The deoxygenation module 3 includes a degassing membrane booster pump 301, a degassing membrane module 302 and a vacuum pump 303. The inlet of the degassing membrane booster pump 301 is connected to the outlet of the electrodeionization product water tank 202. The outlet of the degassing membrane booster pump 301 is connected to the inlet of the liquid phase side of the degassing membrane module 302. The outlet of the liquid phase side of the degassing membrane module is connected to the SCAL type indirect air cooling system; the inlet of the vacuum pump 303 is connected to the gas phase side outlet of the degassing membrane module 302 near the inlet of the liquid phase side.

[0043] Specifically, the feed water pump 101 is installed near the indirect cooling tower and is connected to the circulating water outlet of the indirect cooling tower through a pipeline. The function of the feed water pump 101 is to extract the already cooled indirect cooling circulating water from the indirect cooling tower. The security filter 102 is connected to the outlet end of the feed water pump 101 and is used to remove large particle impurities such as suspended solids in the indirect cooling circulating water to protect the normal operation of subsequent equipment. The inlet of the electrodeionization device 201 is connected to the outlet of the security filter 102 through a pipeline. Exemplarily, the electrodeionization device 201 adopts electrodialysis technology. By applying an electric field, the ions in the water selectively pass through the membrane, thereby achieving the purpose of removing impurity ions in the water. The electrodeionization product water tank 202 is connected to the fresh water outlet end of the electrodeionization device 201 and is used to collect the fresh water after electrodeionization treatment and provide water source for the deaeration module 3. The degassing membrane booster pump 301 is installed at the outlet end of the electrodeionization product water tank 202 and is used to boost the pressure of the fresh water and send it into the degassing membrane module 302. The degassing membrane module 302 has a liquid phase side and a gas phase side. The inlet of the liquid phase side is connected to the outlet of the degassing membrane booster pump 301. The degassing membrane module 302 drives the oxygen in the water to cross the membrane and enter the gas phase side through the pressure difference and concentration difference on both sides of the membrane. The inlet of the vacuum pump 303 is connected to the gas phase side outlet of the degassing membrane module 302 near the inlet of the liquid phase side and is used to evacuate the gas phase side to pump out the oxygen and other gases that have crossed the membrane into the gas phase side, thereby achieving the deaeration effect.

[0044] Using the above-mentioned SCAL type indirect cooling circulating water bypass purification device, the treatment method of the present invention specifically includes the following steps:

[0045] Step 1: Use the feed water pump 101 in the pretreatment module 1 to extract the indirect cooling circulating water cooled by the indirect cooling tower. After the feed water pump 101 is started, the indirect cooling circulating water is transported to the security filter 102 through a pipeline.

[0046] Step 2: In the security filter 102, the indirect cooling circulating water undergoes filtration treatment to remove large particle impurities in the water. The water quality of the filtered indirect cooling circulating water is preliminarily purified to avoid damage to the electrodeionization and degassing membrane module itself by particulate matter.

[0047] Step 3: Transport the indirect cooling circulating water treated by the security filter 102 to the electrodeionization device 201 of the desalination module 2. In the electrodeionization device 201, by applying an electric field, the ions in the water selectively pass through the membrane, thereby removing the impurity ions in the water. The treated fresh water enters the electrodeionization product water tank 202 for collection.

[0048] Step 4: Transport the fresh water in the electrodeionization product water tank 202 to the degassing membrane booster pump 301 of the deaeration module 3. After the degassing membrane booster pump 301 is started, the fresh water is boosted in pressure and sent into the inlet of the liquid phase side of the degassing membrane module 302.

[0049] Step Five: In the degassing membrane module 302, vacuum is drawn at the gas-phase outlet near the liquid-phase side inlet in a vacuum pumping manner. Oxygen in the intercooling circulating water on the liquid-phase side crosses the membrane into the gas-phase side driven by the concentration difference across the membrane and is drawn away by the vacuum pump 303, which can significantly reduce the oxygen content in the intercooling circulating water.

[0050] Step Six: The intercooling circulating water treated by the degassing membrane module 302 returns to the SCAL-type indirect air cooling system from the liquid-phase side outlet. The water quality of the treated intercooling circulating water is improved, and both the oxygen content and the impurity ion content are significantly reduced, thus effectively reducing the corrosion rates of carbon steel and pure aluminum in the system.

[0051] As a more preferred embodiment, as Figure 1 shown, the deoxygenation module 3 in a SCAL-type intercooling circulating water bypass purification device is provided with a multi-stage degassing membrane module 302. The outlet of the degassing membrane booster pump 301 is connected to the liquid-phase side inlet of the first-stage degassing membrane module 302. The liquid-phase sides of the multi-stage degassing membrane modules 302 are connected in series. The liquid-phase side outlet of the last-stage degassing membrane module 302 is connected to the SCAL-type indirect air cooling system; the inlet of the vacuum pump 303 is connected to the gas-phase side outlet of each degassing membrane module 302 near the liquid-phase side inlet. The deoxygenation module 3 further includes a nitrogen purging device and a gas-water separator 304. The nitrogen source of the nitrogen purging device is connected to the gas-phase side inlet of each degassing membrane module 302 near the liquid-phase side outlet. The outlet of the vacuum pump 303 is connected to the inlet of the gas-water separator 304, and the exhaust port of the gas-water separator 304 leads to the atmosphere.

[0052] Specifically, the liquid-phase sides of the multi-stage degassing membrane modules 302 are connected in series, that is, the liquid-phase side outlet of the previous-stage degassing membrane module is connected to the liquid-phase side inlet of the next-stage degassing membrane module. The liquid-phase side outlet of the last-stage degassing membrane module 302 is connected to the SCAL-type indirect air cooling system through a pipeline to return the treated intercooling circulating water to the system. In addition, the inlet of the vacuum pump 303 is connected to the gas-phase side outlet of each degassing membrane module 302 near the liquid-phase side inlet. In this way, when the vacuum pump 303 is started, a negative pressure can be formed on the gas-phase side of each degassing membrane module 302, thereby driving the dissolved oxygen in the liquid-phase side to cross the membrane into the gas-phase side and be extracted. To further improve the deoxygenation effect, the nitrogen source of the nitrogen purging device is connected to the gas-phase side inlet of each degassing membrane module 302 near the liquid-phase side outlet through a pipeline, which can effectively dilute and timely remove the oxygen that crosses the membrane from the liquid-phase side of each degassing membrane module into the vacuum side. The function of the gas-water separator 304 is to separate the water in the gas extracted from the degassing membrane module. The exhaust port of the gas-water separator 304 leads to the atmosphere to discharge the separated gas into the environment.

[0053] The treatment is carried out by using the SCAL type indirect cooling circulating water bypass purification device of this embodiment. The treatment method specifically includes the following steps: The feed water pump 101 in the pretreatment module 1 is used to extract the indirect cooling circulating water that has been cooled down in the indirect cooling tower. The indirect cooling circulating water is transported to the security filter 102 to remove substances such as suspended solids, colloids, and corrosion products in the water, so as to reduce the turbidity of the indirect cooling circulating water and avoid damage to subsequent equipment such as electro-deionization and multi-stage degassing membrane modules. The indirect cooling circulating water treated by the security filter 102 is transported to the desalination module 2, and the electro-deionization device 201 is used to remove impurity ions in the indirect cooling circulating water to reduce the corrosion of pure aluminum in the SCAL type indirect air cooling system. The fresh water produced by the electro-deionization device 201 enters the electro-deionization product water tank 202, and the fresh water in the electro-deionization product water tank 202 is transported to the deoxygenation module 3, and after being boosted by the degassing membrane booster pump 301, it is transported into the liquid phase side inlet of the first-stage degassing membrane module 302 in the multi-stage degassing membrane module 302. The deoxygenation treatment is carried out by combining vacuum pumping and nitrogen purging. Nitrogen is introduced into the gas phase side inlet near the liquid phase side outlet of each stage of the degassing membrane module 302, and vacuum is pumped at the gas phase side outlet near the liquid phase side inlet of each stage of the degassing membrane module 302. Nitrogen purging and the indirect cooling circulating water enter the degassing membrane module 302 in a cross-flow form. As an inert gas, nitrogen dilutes and timely takes away the oxygen that crosses the membrane from the liquid phase side to the vacuum side of each stage of the degassing membrane module. After being treated by the multi-stage degassing membrane module 302, the dissolved oxygen in the indirect cooling circulating water is effectively removed, so as to achieve the purpose of reducing the corrosion of carbon steel. The indirect cooling circulating water treated by each stage of the degassing membrane module 302 returns to the SCAL type indirect air cooling system from the liquid phase side outlet of the last-stage degassing membrane module for system circulation use.

[0054] In summary, a SCAL type indirect cooling circulating water bypass purification device provided by this embodiment, through multi-stage treatment processes such as pretreatment, desalination, and deoxygenation, especially the deoxygenation method that combines multi-stage degassing membrane modules and nitrogen purging, can greatly reduce the corrosion rate of carbon steel and pure aluminum in the SCAL type indirect air cooling system without adding drugs.

[0055] In an implementable manner, as Figure 2 shown, the pretreatment module 1 further includes a magnetic separator 103 arranged between the outlet of the feed water pump 101 and the inlet of the security filter 102, and the magnetic separator 103 is used to remove ferromagnetic corrosion products in the indirect cooling circulating water.

[0056] Specifically, the iron remover 103 is a strong magnetic device, and its purpose is to remove ferromagnetic corrosion products in the indirect cooling circulating water. In the SCAL type indirect air cooling system, due to long-term operation and possible corrosive environment, the indirect cooling circulating water may contain a large amount of ferromagnetic corrosion products, such as rust, iron filings, etc. If these corrosion products directly enter the security filter 102, the electrodeionization device or the multi-stage degassing membrane module, they may cause blockage, wear or reduce the processing efficiency of these devices. Therefore, the iron remover 103 is installed in the pretreatment module 1. Through its strong magnetic field effect, the iron remover 103 can adsorb and remove the ferromagnetic corrosion products in the indirect cooling circulating water, thereby purifying the water quality.

[0057] In actual operation, the indirect cooling circulating water is first pumped and pressurized by the feed water pump 303, and then flows through the iron remover 103. The iron remover 103 uses its strong magnetic field to adsorb and remove the ferromagnetic corrosion products in the water. The treated indirect cooling circulating water then enters the security filter 102 for further filtration treatment to remove suspended solids, colloids and other non-magnetic impurities in the water. After being treated by the security filter 102, the water quality of the indirect cooling circulating water has been improved, which can ensure the normal operation and efficient treatment of the subsequent electrodeionization device and multi-stage degassing membrane module.

[0058] In one implementable manner, the degassing membrane module 302 adopts a shell-and-tube membrane module made of hollow fiber hydrophobic microporous membranes, and the material of the hollow fiber hydrophobic microporous membranes is polytetrafluoroethylene or polyvinylidene fluoride. The hollow fiber hydrophobic microporous membranes have strong hydrophobicity. Therefore, water molecules cannot pass through their pores, while gas molecules in the water can pass through the pores driven by the concentration difference on both sides of the membrane.

[0059] Preferably, the concentrated water outlet of the electrodeionization device 201 is connected to the power plant desulfurization system for recovering the concentrated water.

[0060] Preferably, the filter material of the security filter 102 is polypropylene or PP cotton, which is used to remove suspended solids, colloids and corrosion products in the indirect cooling circulating water.

[0061] In one implementable manner, as Figure 1 and Figure 2 shown, the treatment device further includes an indirect cooling system make-up water treatment pipeline, and the make-up water treatment pipeline is connected to the inlet of the feed water pump 101 for deoxidation and desalination treatment of the indirect cooling system make-up water.

[0062] Embodiment 1

[0063] A bypass purification device for the indirect cooling circulating water of the SCAL type is provided with a pipeline for the make-up water of the indirect cooling system to this embodiment, and can simultaneously treat the make-up water of the indirect cooling system.

[0064] The device diagram of this embodiment can be seen in Figure 1, its main body includes a feed water pump 101, a security filter 102, an electrodeionization device 201, an electrodeionization product water tank 202, a degassing membrane booster pump 301, a degassing membrane module 302, a vacuum pump 303, a gas-liquid separator 304, and connecting pipes, valves, etc. The specific connection method is as follows:

[0065] Use pipelines to connect the indirect cooling circulating water cooled in the indirect cooling tower and the makeup water of the indirect cooling system to the inlet of the feed water pump 101 of this embodiment. The outlet of the feed water pump 101 is connected to the inlet of the security filter 102. The outlet of the security filter 102 is connected to the inlet of the electrodeionization device 201. The fresh water outlet of the electrodeionization device 201 is connected to the inlet of the electrodeionization product water tank 202. The outlet of the electrodeionization product water tank 202 is connected to the liquid phase side inlet of the first-stage degassing membrane module 302 of the multi-stage degassing membrane module through the degassing membrane booster pump 301. Its liquid phase side outlet is connected to the liquid phase side inlet of the next-stage degassing membrane module 302. The liquid phase side outlet of the last-stage degassing membrane module 302 is connected to the indirect cooling system. The gas phase side inlet of the degassing membrane module 302 near the liquid phase side outlet is connected to a nitrogen source. The gas phase side outlet near the liquid phase side inlet is connected to the inlet of the vacuum pump 303. The outlet of the vacuum pump 303 is connected to the inlet of the gas-liquid separator 304. The exhaust gas of the gas-liquid separator 304 is directly discharged to the atmosphere.

[0066] The operation method of the device in this embodiment is as follows:

[0067] The indirect cooling circulating water cooled in the indirect cooling tower and the makeup water of the indirect cooling system are pressurized by the feed water pump 101 and then introduced into the security filter 102. Substances such as suspended solids, colloids, and corrosion products in the water are removed. The water discharged from the security filter 102 enters the inlet of the electrodeionization device 201. The concentrated water generated by the electrodeionization device 201 can be recycled to systems with low salt content requirements such as desulfurization. The fresh water produced by the electrodeionization device 201 enters the electrodeionization product water tank 202. The fresh water produced by the electrodeionization is transported to the liquid phase side inlet of the first-stage degassing membrane module 302 of the multi-stage membrane module through the degassing membrane booster pump 301. After being processed by the multi-stage series degassing membrane module 302, it returns to the indirect cooling system from the liquid phase side outlet of the last-stage degassing membrane module 302. Nitrogen is introduced into the gas phase side inlet of each degassing membrane module 302 near the liquid phase side outlet, and vacuum pumping is performed at the gas phase side outlet of each degassing membrane module 302 near the liquid phase side inlet by using the vacuum pump 303, so that the nitrogen purge and the indirect cooling circulating water enter the degassing membrane module 302 in a cross-flow form. The oxygen in the liquid phase side indirect cooling circulating water enters the gas phase side across the membrane under the drive of the concentration difference on both sides of the membrane and is pumped away by the vacuum pump 303 and enters the gas-liquid separator 304. The extracted gas is discharged to the atmosphere, and the separated water can be recycled to systems with no oxygen content requirements such as the power plant industrial water system and the demineralized water preparation system.

[0068] In this embodiment, the filler of the security filter 102 is a polypropylene filter element; the electrodeionization uses the Suez E-Cell MK-3 module, and the produced concentrated water is recycled to the desulfurization system; a total of three stages of series-connected degassing membrane modules are provided. The material of the degassing membrane module 302 is polytetrafluoroethylene (PTFE), and the outer diameter of its membrane filaments is 300 μm and the inner diameter is 200 μm; the vacuum pump 303 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 conductivity of the indirect cooling circulating water entering the electrodeionization device 201 is 30 to 35 μS / cm. After being treated by electrodeionization and multi-stage degassing membranes, the conductivity of the indirect cooling circulating water returned to the indirect cooling system from the liquid-phase side outlet of the last-stage degassing membrane module 302 drops to 0.07 to 0.09 μS / cm, and the dissolved oxygen content drops to less than 20 μg / L.

[0069] Embodiment 2

[0070] The difference between this embodiment and Embodiment 1 is that: in this embodiment, a magnetic separator 103 is installed in front of the security filter 102. The magnetic separator 103 is a strong magnetic separator to remove ferromagnetic corrosion products in the indirect cooling circulating water. On the one hand, it can ensure the inlet turbidity of the membrane module, and on the other hand, it can extend the working life of the membrane module and the pre-filter.

[0071] The device diagram of this embodiment is shown in Figure 2 , and its main body includes a feed water pump 101, a security filter 102, a magnetic separator 103, an electrodeionization device 201, an electrodeionization product water tank 202, a degassing membrane booster pump 301, a degassing membrane module 302, a vacuum pump 303, a gas-water separator 304, and connecting pipes, valves, etc. The specific connection method is as follows:

[0072] The indirect cooling circulating water cooled in the indirect cooling tower and the makeup water of the indirect cooling system are connected to the inlet of the feed water pump 101 of this embodiment by pipelines. The outlet of the feed water pump 101 is connected to the inlet of the magnetic separator 103. The outlet of the magnetic separator 103 is connected to the inlet of the security filter 102. The outlet of the security filter 102 is connected to the inlet of the electrodeionization device 201. The fresh water outlet of the electrodeionization device 201 is connected to the inlet of the electrodeionization product water tank 202. The outlet of the electrodeionization product water tank 202 is connected to the liquid-phase side inlet of the first-stage degassing membrane module 302 of the multi-stage degassing membrane module through the degassing membrane booster pump 301. Its liquid-phase side outlet is connected to the liquid-phase side inlet of the next-stage degassing membrane module 302. The liquid-phase side outlet of the last-stage degassing membrane module 302 is connected to the indirect cooling system. The gas-phase side inlet of the degassing membrane module 302 near the liquid-phase side outlet is connected to a nitrogen source. The gas-phase side outlet near the liquid-phase side inlet is connected to the inlet of the vacuum pump 303. The outlet of the vacuum pump 303 is connected to the inlet of the gas-water separator 304. The exhaust gas of the gas-water separator 304 is directly discharged to the atmosphere.

[0073] The operation method of the device in this embodiment is as follows:

[0074] The indirect cooling circulating water cooled by the indirect cooling tower and the makeup water of the indirect cooling system are boosted by the feed water pump 101 and introduced into the iron remover 103 to remove ferromagnetic corrosion products in the indirect cooling circulating water. After being treated by the security filter 102, substances such as suspended solids, colloids, and corrosion products in the water are removed. The water discharged from the security filter 102 enters the inlet of the electrodeionization device 201. The concentrated water generated by the electrodeionization device 201 can be recycled to systems with low requirements for salt content such as desulfurization. The fresh water produced by the electrodeionization device 201 enters the electrodeionization product water tank 202. The fresh water produced by the electrodeionization is transported by the degassing membrane booster pump 301 to the liquid-phase side inlet of the first-stage degassing membrane module 302 of the multi-stage membrane module. After being treated by the multi-stage series-connected degassing membrane module 302, it returns to the indirect cooling system from the liquid-phase side outlet of the last-stage degassing membrane module 302. Nitrogen is introduced into the gas-phase side inlet near the liquid-phase side outlet of each stage of the degassing membrane module 302, and vacuum pumping is carried out by the vacuum pump 303 at the gas-phase side outlet near the liquid-phase side inlet of each stage of the degassing membrane module 302, so that nitrogen purging and the indirect cooling circulating water enter the degassing membrane module 302 in a cross-flow form. The oxygen in the liquid-phase side indirect cooling circulating water enters the gas-phase side across the membrane under the drive of the concentration difference across the membrane and is pumped away by the vacuum pump 303 and enters the gas-water separator 304. The extracted gas is discharged to the atmosphere, and the separated water can be recycled to systems with no requirements for dissolved oxygen content such as the power plant industrial water system and the demineralized water preparation system.

[0075] In this embodiment, the iron remover 103 is made of neodymium magnet strong magnetic material; the filler of the security filter 102 adopts a polypropylene filter element; the electrodeionization adopts the Suez E-Cell MK-3 module, and the generated concentrated water is recycled to the desulfurization system; a total of three-stage series-connected membrane modules are set. The degassing membrane module 302 is made of polytetrafluoroethylene (PTFE), its membrane filament outer diameter is 300 μm, and the inner diameter is 200 μm; the vacuum pump 303 adopts 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 conductivity of the indirect cooling circulating water entering the electrodeionization device 201 is 30 to 35 μS / cm. After being treated by electrodeionization and multi-stage degassing membrane, the conductivity of the indirect cooling circulating water returning to the indirect cooling system from the liquid-phase side outlet of the last-stage membrane module drops to 0.07 to 0.09 μS / cm, and the dissolved oxygen content drops to below 20 μg / L.

[0076] 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.

[0077] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0078] In the present invention, unless otherwise clearly defined and limited, terms such as "connected" and "coupled" shall be construed broadly. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection, an electrical connection, or communicable with each other; it may be directly connected, or indirectly connected through an intermediate medium, and 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.

[0079] In the present invention, unless otherwise clearly defined and 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", "below" and "beneath" 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 lower than that of the second feature.

[0080] In the present invention, terms such as "an 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 representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0081] 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 technical field within the technical scope disclosed by the present invention can still modify the technical solutions described in the foregoing embodiments, or can easily think of changes, or perform 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 shall be subject to the protection scope of the claims.

Claims

1. A SCAL type indirect cooling circulating water bypass purification device, characterized in that: include: The pretreatment module (1) comprises a water supply pump (101) and a security filter (102), wherein the water supply pump (101) is used to extract intercooling circulating water after cooling in an intercooling tower and transport it to the inlet of the security filter (102); The desalination module (2) comprises an electric desalination device (201) and an electric desalination water production tank (202), wherein the inlet of the electric desalination device (201) is connected to the outlet of the security filter (102), and the inlet of the electric desalination water production tank (202) is connected to the fresh water outlet of the electric desalination device (201); The deoxygenation module (3) comprises a degassing membrane booster pump (301), a degassing membrane assembly (302) and a vacuum pump (303), wherein the inlet of the degassing membrane booster pump (301) is connected to the outlet of the electric desalination water production tank (202), the outlet of the degassing membrane booster pump (301) is connected to the liquid phase side inlet of the degassing membrane assembly (302), and the liquid phase side outlet of the degassing membrane assembly is connected to a SCAL type indirect air cooling system; the inlet of the vacuum pump (303) is connected to the gas phase side outlet of the degassing membrane assembly (302) close to the liquid phase side inlet.

2. A SCAL type indirect cooling circulating water bypass purification device according to claim 1, characterized in that: The deoxygenation module (3) is provided with a multi-stage degassing membrane assembly (302), the outlet of the degassing membrane booster pump (301) is connected to the liquid phase side inlet of the first-stage degassing membrane assembly (302), the liquid phase sides of each stage of the multi-stage degassing membrane assembly (302) are connected in series, and the liquid phase side outlet of the last stage degassing membrane assembly (302) is connected to a SCAL type indirect air cooling system; the inlet of the vacuum pump (303) is connected to the gas phase side outlet of each stage of the degassing membrane assembly (302) close to the liquid phase side inlet.

3. A SCAL type indirect cooling circulating water bypass purification device according to claim 2, characterized in that: The deoxygenation module (3) further comprises a nitrogen purge device, wherein a nitrogen source of the nitrogen purge device is connected to a gas phase side inlet close to a liquid phase side outlet of each stage of the degassing membrane assembly (302).

4. A SCAL type indirect cooling circulating water bypass purification device according to claim 1, characterized in that: The deoxygenation module (3) further comprises a gas-water separator (304), the outlet of the vacuum pump (303) is connected to the inlet of the gas-water separator (304), and the exhaust port of the gas-water separator (304) is connected to the atmosphere.

5. A SCAL type indirect cooling circulating water bypass purification device according to claim 1, characterized in that: The pretreatment module (1) further comprises an iron remover (103) arranged between the outlet of the water supply pump (101) and the inlet of the safety filter (102), wherein the iron remover (103) is used to remove ferromagnetic corrosion products in the intercooling circulating water.

6. A SCAL type indirect cooling circulating water bypass purification device according to claim 1, characterized in that: The degassing membrane assembly (302) is a shell-and-tube membrane assembly made of a hollow fiber hydrophobic microporous membrane, wherein the material of the hollow fiber hydrophobic microporous membrane is polytetrafluoroethylene or polyvinylidene fluoride.

7. A SCAL type indirect cooling circulating water bypass purification device according to claim 1, characterized in that: The concentrated water outlet of the electric desalination device (201) is connected to the desulfurization system of the power plant for recovering concentrated water.

8. A SCAL type indirect cooling circulating water bypass purification device according to claim 1, characterized in that: The filter material of the security filter (102) is polypropylene or PP cotton, which is used to remove suspended matter, colloids and corrosion products in the intercooling circulating water.

9. A SCAL type indirect cooling circulating water bypass purification device according to claim 1, characterized in that: The treatment device also includes an indirect cooling system feed water treatment pipeline, which is connected to the inlet of the water supply pump (101) and is used to deoxygenate and desalinate the feed water of the indirect cooling system.

10. A SCAL type indirect cooling circulating water bypass purification method, characterized in that: Using a SCAL type intercooling circulating water bypass purification device according to any one of claims 1 to 9, the method comprises: The intercooling circulating water after cooling in the intercooling tower is extracted by the water supply pump (101) in the pretreatment module (1), and the intercooling circulating water is transported to the security filter (102) to remove impurities in the water; the intercooling circulating water treated by the security filter (102) is transported to the desalination module (2), and the impurity ions in the intercooling circulating water are removed by the electric desalination device (201), and the electric desalination device (201) produces fresh water that enters the electric desalination water production tank (202), and the fresh water in the electric desalination water production tank (202) is The oxygen is transported to the deoxygenation module (3), and after being pressurized by the degassing membrane booster pump (301), it is transported to the liquid phase side inlet of the degassing membrane assembly (302). A vacuum pump (303) is used to evacuate the gas phase side outlet of the degassing membrane assembly (302) close to the liquid phase side inlet. Driven by the concentration difference on both sides of the membrane, the oxygen in the intercooling circulating water on the liquid phase side crosses the membrane into the gas phase side and is pumped away by the vacuum pump (303). The intercooling circulating water treated by the degassing membrane assembly (302) returns to the SCAL type indirect air cooling system from the liquid phase side outlet.

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