Power plant circulating water softening treatment system and treatment method

Abstract

The invention provides a power plant circulating water softening treatment system and method. The system comprises a crystallization granulation fluidized bed, a solid-liquid separation fluidized bed, a reverse osmosis membrane device, a calcium sulfate crystallization reactor and a circulating water tank. The method comprises the following steps: introducing circulating water into a crystallization granulation fluidized bed, circularly crystallizing calcium carbonate, discharging the crystallized calcium carbonate, introducing generated magnesium hydroxide precipitate and the circulating water into a solid-liquid separation fluidized bed, circularly flocculating the magnesium hydroxide precipitate to form sludge, introducing the sludge-removed circulating water into a reverse osmosis membrane device, and separating the sludge from the reverse osmosis membrane device. The reverse osmosis membrane device is used for removing chloride ions and sulfate ions in the circulating water to obtain clear water and concentrated water, the clear water flows back to the circulating water tank, the concentrated water is introduced into the calcium sulfate crystallization reactor, the supersaturated concentrated water is induced to generate calcium sulfate crystallization, the concentrated water is softened, and the softened water flows back to the circulating water tank. According to the invention, calcium hardness of circulating water can be removed, turbidity can be reduced, and scaling phenomenon and accident risk in subsequent use can be reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of water treatment, and in particular to a circulating water softening treatment system and a treatment method for a power plant. Background Art

[0002] At present, with the use of circulating water in power plants, the proportion of urban water as circulating water replenishment is increasing, resulting in an increase in the content of calcium and magnesium ions in the water, and the scaling risk and softening pressure faced by power plants are also increasing. The current softening process for circulating water in power plants is "mechanical accelerated clarification tank + quartz sand filter". In addition, in order to control operating costs, most coal-fired power plants add calcium hydroxide during softening. Although this agent is low in cost, it can only remove alkalinity and cannot remove calcium ions. Therefore, it will still increase the scaling and accident risks of subsequent condensers. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems in the related art to a certain extent. To this end, the present invention provides a circulating water softening treatment system and treatment method for a power plant, which can remove calcium hardness from the circulating water, reduce turbidity, and reduce scaling and accident risks in subsequent use.

[0004] One embodiment of the present invention provides a power plant circulating water softening treatment system, including: a crystallization granulation fluidized bed, a solid-liquid separation fluidized bed, a reverse osmosis membrane device, a calcium sulfate crystallization reactor and a circulating water pool.

[0005] The crystallization granulation fluidized bed comprises a first chamber and a water inlet, a feed inlet, a crystal discharge outlet and a discharge outlet connected to the first chamber, the water inlet of the crystallization granulation fluidized bed is suitable for introducing circulating water to be treated into the first chamber, the feed inlet of the crystallization granulation fluidized bed is suitable for adding crystal seeds and reagents into the first chamber, the crystal discharge outlet of the crystallization granulation fluidized bed is suitable for discharging calcium carbonate crystals, and the discharge outlet of the crystallization granulation fluidized bed is suitable for discharging the treated circulating water and the magnesium hydroxide precipitate generated after the reaction into the solid-liquid separation fluidized bed.

[0006] The solid-liquid separation fluidized bed has a second chamber and a feed port, a flocculant inlet, a sludge outlet and a water outlet connected to the second chamber. The feed port of the solid-liquid separation fluidized bed is connected to the discharge port of the crystallization granulation fluidized bed. The flocculant inlet of the solid-liquid separation fluidized bed is suitable for adding flocculant to the second chamber. The sludge outlet of the solid-liquid separation fluidized bed is suitable for discharging sludge flocculated by magnesium hydroxide precipitation.

[0007] The reverse osmosis membrane device has a third chamber and a water inlet, a clean water outlet and a concentrated water outlet connected to the third chamber. The third chamber is provided with a reverse osmosis membrane. The water inlet of the reverse osmosis membrane device is connected to the water outlet of the solid-liquid separation fluidized bed.

[0008] The calcium sulfate crystallization reactor comprises a fourth chamber and a water inlet, a crystal inlet, a crystal outlet and a water outlet connected to the fourth chamber. The water inlet of the calcium sulfate crystallization reactor is connected to the concentrated water outlet of the reverse osmosis membrane device. The crystal inlet of the calcium sulfate crystallization reactor is suitable for adding crystal seeds for inducing concentrated water to produce calcium sulfate crystals into the fourth chamber. The crystal outlet of the calcium sulfate crystallization reactor is suitable for discharging the produced calcium sulfate crystals.

[0009] The circulating water pool has a water inlet, a circulating water inlet, a water outlet and a water outlet. The water inlet of the circulating water pool is suitable for introducing circulating water from the power plant. The circulating water inlet of the circulating water pool is respectively connected to the clean water outlet of the reverse osmosis membrane device and the water outlet of the calcium sulfate crystallization reactor to collect the treated circulating water. The water outlet of the circulating water pool is connected to the power plant.

[0010] In some embodiments, the water outlet and the water inlet of the circulating water pool are respectively connected to filtering devices.

[0011] In some embodiments, a water pump is connected to the circulating water inlet of the circulating water pool.

[0012] In some embodiments, the water outlet of the crystallization granulation fluidized bed is connected to the circulating water inlet of the circulating water pool through a first circulating pipe, and the water outlet of the solid-liquid separation fluidized bed is connected to the circulating water inlet of the circulating water pool through a second circulating pipe.

[0013] In some embodiments, a first flow valve is connected to the first circulation pipe, and a second flow valve is connected to the second circulation pipe.

[0014] In some embodiments, the sludge outlet of the solid-liquid separation fluidized bed is connected to a first collecting tank, and the crystal outlet of the calcium sulfate crystallization reactor is connected to a second collecting tank.

[0015] In some embodiments, a liquid level monitoring device is provided in the circulating water pool to monitor the liquid level of the circulating water pool. The water outlet of the circulating water pool is connected to the power plant through a water pipe, and a regulating valve is connected to the water pipe. The regulating valve and the liquid level monitoring device are electrically connected through a control device.

[0016] In some embodiments, a hardness meter is provided in the circulating water pool, and the hardness meter is electrically connected to the regulating valve through a control device.

[0017] Another embodiment of the present invention provides a method for softening circulating water in a power plant, using the above-mentioned circulating water softening treatment system in a power plant, comprising the following steps:

[0018] The circulating water in the circulating water pool is passed into the crystallization granulation fluidized bed, and crystal seeds and reagents are added into the crystallization granulation fluidized bed to react with calcium ions and magnesium ions in the circulating water. The generated calcium carbonate is circulated and crystallized and then discharged. At the same time, the generated magnesium hydroxide precipitate and the treated circulating water are passed into the solid-liquid separation fluidized bed.

[0019] A flocculant is introduced into the solid-liquid separation fluidized bed to cause magnesium hydroxide to precipitate and flocculate in a cycle to form sludge particles, which are then discharged from the sludge outlet and the circulating water from which the sludge has been removed is introduced into the reverse osmosis membrane device.

[0020] The reverse osmosis membrane device removes chloride ions and sulfate ions in the circulating water to obtain clean water and concentrated water mixed with chloride ions and sulfate ions. The clean water is returned to the circulating water pool, and the concentrated water is passed into the calcium sulfate crystallization reactor.

[0021] Adding seeds into the calcium sulfate crystallization reactor induces calcium sulfate crystallization in the supersaturated concentrated water, softens the concentrated water, and returns the softened water to the circulating water pool.

[0022] In some embodiments, the agent comprises sodium hydroxide and sodium bicarbonate. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings.

[0024] in:

[0025] Figure 1 It is a structural schematic diagram of a power plant circulating water softening treatment system in an embodiment of the present invention;

[0026] Reference numerals:

[0027] 1. Circulating water pool; 2. Crystallization granulation fluidized bed; 3. Solid-liquid separation fluidized bed; 4. Reverse osmosis membrane device; 5. Calcium sulfate crystallization reactor. DETAILED DESCRIPTION

[0028] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0029] The following describes a power plant circulating water softening treatment system and treatment method according to an embodiment of the present invention with reference to the accompanying drawings.

[0030] like Figure 1 As shown, an embodiment of the present invention provides a power plant circulating water softening treatment system, including: a crystallization granulation fluidized bed 2, a solid-liquid separation fluidized bed 3, a reverse osmosis membrane device 4, a calcium sulfate crystallization reactor 5 and a circulating water pool 1.

[0031] The crystallization granulation fluidized bed 2 has a first chamber and a water inlet, a feed inlet, a crystal discharge outlet and a discharge outlet connected to the first chamber. The water inlet of the crystallization granulation fluidized bed 2 is suitable for introducing circulating water to be treated into the first chamber, the feed inlet of the crystallization granulation fluidized bed 2 is suitable for adding crystal seeds and reagents into the first chamber, the crystal discharge outlet of the crystallization granulation fluidized bed 2 is suitable for discharging calcium carbonate crystals, and the discharge outlet of the crystallization granulation fluidized bed 2 is suitable for discharging the treated circulating water and the magnesium hydroxide precipitate generated after the reaction to the solid-liquid separation fluidized bed 3.

[0032] The solid-liquid separation fluidized bed 3 has a second chamber and a feed port, a flocculant inlet, a sludge outlet and a water outlet connected to the second chamber. The feed port of the solid-liquid separation fluidized bed 3 is connected to the discharge port of the crystallization granulation fluidized bed 2. The flocculant inlet of the solid-liquid separation fluidized bed 3 is suitable for adding flocculant to the second chamber. The sludge outlet of the solid-liquid separation fluidized bed 3 is suitable for discharging the sludge flocculated by magnesium hydroxide precipitation.

[0033] The reverse osmosis membrane device 4 has a third chamber and a water inlet, a clean water outlet and a concentrated water outlet connected to the third chamber. A reverse osmosis membrane is arranged in the third chamber. The water inlet of the reverse osmosis membrane device 4 is connected to the water outlet of the solid-liquid separation fluidized bed 3 .

[0034] The calcium sulfate crystallization reactor 5 has a fourth chamber and a water inlet, a crystal inlet, a crystal outlet and a water outlet connected to the fourth chamber. The water inlet of the calcium sulfate crystallization reactor 5 is connected to the concentrated water outlet of the reverse osmosis membrane device 4. The crystal inlet of the calcium sulfate crystallization reactor 5 is suitable for adding crystal seeds for inducing concentrated water to produce calcium sulfate crystals into the fourth chamber. The crystal outlet of the calcium sulfate crystallization reactor 5 is suitable for discharging the produced calcium sulfate crystals.

[0035] The circulating water pool 1 has a water inlet, a circulating water inlet, a water outlet and a water outlet. The water inlet of the circulating water pool 1 is suitable for introducing circulating water from the power plant. The circulating water inlet of the circulating water pool 1 is respectively connected to the clean water outlet of the reverse osmosis membrane device 4 and the water outlet of the calcium sulfate crystallization reactor 5 to collect the treated circulating water. The water outlet of the circulating water pool 1 is connected to the power plant.

[0036] The embodiment of the present invention can remove calcium hardness from circulating water, reduce turbidity, and reduce scaling and accident risks in subsequent use by arranging a crystallization granulation fluidized bed 2, a solid-liquid separation fluidized bed 3, a reverse osmosis membrane device 4, and a calcium sulfate crystallization reactor 5.

[0037] By setting up a crystallization granulation fluidized bed 2 and introducing sodium hydroxide and sodium bicarbonate reagents into the crystallization granulation fluidized bed 2, about 80% of the calcium ions in the circulating water can be removed. At the same time, the hydroxide ions in the crystallization granulation fluidized bed 2 can react with the magnesium ions in the circulating water to form precipitation, thereby removing the magnesium ions in the circulating water.

[0038] By setting up the solid-liquid separation fluidized bed 3, the precipitate in the circulating water can be flocculated into high-density particles, so that the turbidity of the outlet water can reach below 5NTU.

[0039] Since the concentrated water discharged from the reverse osmosis membrane device 4 has the characteristics of high calcium and high sulfate, by setting up a calcium sulfate crystallization reactor 5, the supersaturated calcium ions and sulfate ions in the concentrated water can be induced to form calcium sulfate crystals, which can reduce the discharge of wastewater.

[0040] In some embodiments, the water outlet and the water inlet of the circulating water pool 1 are respectively connected to filtering devices, so as to filter out solid impurities in the circulating water pool 1 and prevent the solid impurities from entering the equipment and causing damage to the equipment.

[0041] In some embodiments, a water pump is connected to the circulating water inlet of the circulating water pool 1 to allow the circulating water to quickly flow into the circulating water pool 1 .

[0042] In some embodiments, the water outlet of the crystallization granulation fluidized bed 2 is connected to the circulating water inlet of the circulating water pool 1 through a first circulating pipe, and the water outlet of the solid-liquid separation fluidized bed 3 is connected to the circulating water inlet of the circulating water pool 1 through a second circulating pipe. The circulating water treated by the crystallization granulation fluidized bed 2 and the solid-liquid separation fluidized bed 3 can be returned to the circulating water pool 1, mixed with the untreated circulating water to reduce the ion concentration, and then softened, which can reduce the water treatment pressure of the overall system.

[0043] In some embodiments, a first flow valve is connected to the first circulation pipe, and a second flow valve is connected to the second circulation pipe. The flow rate of the circulating water returned to the circulating water pool 1 can be adjusted according to actual needs.

[0044] In some embodiments, the sludge outlet of the solid-liquid separation fluidized bed 3 is connected to the first collection tank, and the crystal outlet of the calcium sulfate crystallization reactor 5 is connected to the second collection tank. It is convenient to collect the sludge and crystals, and the crystals can be reused.

[0045] In some embodiments, a liquid level monitoring device is provided in the circulating water pool 1 to monitor the liquid level of the circulating water pool 1. The water outlet of the circulating water pool 1 is connected to the power plant through a water pipe, and a regulating valve is connected to the water pipe. The regulating valve and the liquid level monitoring device are electrically connected through a control device. The water output is automatically regulated by the water level information monitored by the liquid level monitoring device.

[0046] In some embodiments, a hardness meter is provided in the circulating water pool 1, and the hardness meter is electrically connected to the regulating valve through a control device. The water output is automatically regulated by the hardness information monitored by the hardness meter.

[0047] Another embodiment of the present invention provides a method for softening circulating water in a power plant, using the above-mentioned circulating water softening treatment system in a power plant, comprising the following steps:

[0048] The circulating water in the circulating water pool 1 is passed into the crystallization granulation fluidized bed 2, and crystal seeds and reagents are added into the crystallization granulation fluidized bed 2 to react with calcium ions and magnesium ions in the circulating water, and the generated calcium carbonate is circulated and crystallized and then discharged. At the same time, the generated magnesium hydroxide precipitate and the treated circulating water are passed into the solid-liquid separation fluidized bed 3.

[0049] A flocculant is introduced into the solid-liquid separation fluidized bed 3 to cause magnesium hydroxide to precipitate and flocculate in a cycle to form high-density sludge particles, which are then discharged from the sludge outlet, and the circulating water from which the sludge has been removed is introduced into the reverse osmosis membrane device 4.

[0050] The reverse osmosis membrane device 4 removes chloride ions and sulfate ions in the circulating water to obtain clean water and concentrated water mixed with chloride ions and sulfate ions. The clean water is returned to the circulating water pool 1, and the concentrated water is passed into the calcium sulfate crystallization reactor 5.

[0051] Seed crystals are added to the calcium sulfate crystallization reactor 5 to induce calcium sulfate crystallization in the supersaturated concentrated water, soften the concentrated water, and the softened water flows back to the circulating water pool 1.

[0052] The embodiments of the present invention can remove calcium hardness from circulating water, reduce turbidity, and reduce scaling and accident risks in subsequent use.

[0053] It should be noted that, at present, the industry mainly uses traditional chemical methods to soften high-hardness circulating water. The main process is to pass the sewage through a mechanical acceleration clarification tank or a high-density clarification tank, and add reagents to react the calcium ions in the sewage with carbonate ions to form calcium carbonate precipitates. However, the main problem of this method is that the generated calcium carbonate precipitate will eventually form chemical sludge with a high water content, which is difficult to handle and cannot be recycled. Compared with the traditional softening method, the softening treatment method of the embodiment of the present invention can produce high-purity calcium carbonate crystalline particles with economic value. At the same time, the amount of sludge formed by magnesium hydroxide precipitation is small and the water content is lower, which solves the problem of large sludge amount and high water content in traditional processes.

[0054] In some embodiments, the agent includes sodium hydroxide and sodium bicarbonate. The role of sodium hydroxide is to remove magnesium ions in the circulating water, and sodium hydroxide reacts with magnesium ions in the circulating water to form magnesium hydroxide precipitation. The role of sodium bicarbonate is to remove calcium ions in the circulating water, and sodium bicarbonate reacts with calcium ions in the circulating water to form calcium carbonate precipitation.

[0055] The present invention is further described below through specific examples.

[0056] Example 1

[0057] Taking the third phase unit of a coal-fired power plant in Henan, China as an example, the circulating water flow rate is 700m 3 / h, build 700m 3 / h circulating water bypass softening system and 100m 3 / h reverse osmosis concentrated water calcium sulfate crystallization treatment system, after the treatment of crystallization granulation fluidized bed 2 and solid-liquid separation fluidized bed 3, 200m 3 / h of effluent is directly returned to the circulating water pool 1 as replenishment water, and the remaining 500m 3 / h of effluent enters the reverse osmosis membrane device 4 for further deep treatment. The treatment efficiency of the reverse osmosis membrane device 4 is 60%. 3 / h of clean water is introduced into the circulating water pool 1 as make-up water, 200m 3 / h of reverse osmosis concentrated water discharged from the reverse osmosis membrane, of which 100m 3 / h of reverse osmosis concentrated water enters the calcium sulfate crystallization reactor 5, where it is softened and then subjected to terminal treatment. 3 / h of concentrated water will enter the desulfurization system to participate in flue gas desulfurization.

[0058] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0059] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0060] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0061] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0062] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction 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 described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0063] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A power plant circulating water softening treatment system, characterized in that: include: A crystallization granulation fluidized bed, the crystallization granulation fluidized bed having a first chamber and a water inlet, a feed inlet, a crystal discharge outlet and a discharge outlet connected to the first chamber, the water inlet of the crystallization granulation fluidized bed being suitable for introducing circulating water to be treated into the first chamber, the feed inlet of the crystallization granulation fluidized bed being suitable for adding crystal seeds and reagents into the first chamber, the crystal discharge outlet of the crystallization granulation fluidized bed being suitable for discharging calcium carbonate crystals, and the discharge outlet of the crystallization granulation fluidized bed being suitable for discharging the treated circulating water and the magnesium hydroxide precipitate generated after the reaction into a solid-liquid separation fluidized bed; A solid-liquid separation fluidized bed, the solid-liquid separation fluidized bed having a second chamber and a feed port, a flocculant inlet, a sludge outlet and a water outlet connected to the second chamber, the feed port of the solid-liquid separation fluidized bed being connected to the discharge port of the crystallization granulation fluidized bed, the flocculant inlet of the solid-liquid separation fluidized bed being suitable for adding flocculant to the second chamber, and the sludge outlet of the solid-liquid separation fluidized bed being suitable for discharging sludge flocculated by magnesium hydroxide precipitation; A reverse osmosis membrane device, the reverse osmosis membrane device having a third chamber and a water inlet, a clean water outlet and a concentrated water outlet connected to the third chamber, a reverse osmosis membrane is arranged in the third chamber, and the water inlet of the reverse osmosis membrane device is connected to the water outlet of the solid-liquid separation fluidized bed; A calcium sulfate crystallization reactor, the calcium sulfate crystallization reactor having a fourth chamber and a water inlet, a crystal inlet, a crystal outlet and a water outlet connected to the fourth chamber, the water inlet of the calcium sulfate crystallization reactor being connected to the concentrated water outlet of the reverse osmosis membrane device, the crystal inlet of the calcium sulfate crystallization reactor being suitable for adding crystal seeds for inducing concentrated water to produce calcium sulfate crystals into the fourth chamber, and the crystal outlet of the calcium sulfate crystallization reactor being suitable for discharging the produced calcium sulfate crystals; A circulating water pool, wherein the circulating water pool has a water inlet, a circulating water inlet, a water outlet and a water outlet. The water inlet of the circulating water pool is suitable for introducing circulating water from a power plant. The circulating water inlet of the circulating water pool is respectively connected to the clean water outlet of the reverse osmosis membrane device and the water outlet of the calcium sulfate crystallization reactor to collect the treated circulating water. The water outlet of the circulating water pool is connected to the power plant.

2. The power plant circulating water softening treatment system according to claim 1, characterized in that: The water outlet and the water inlet of the circulating water pool are respectively connected to filtering devices.

3. The power plant circulating water softening treatment system according to claim 1, characterized in that: A water pump is connected to the circulating water inlet of the circulating water pool.

4. The power plant circulating water softening treatment system according to claim 1, characterized in that: The water outlet of the crystallization granulation fluidized bed is connected to the circulating water inlet of the circulating water pool through a first circulating pipe, and the water outlet of the solid-liquid separation fluidized bed is connected to the circulating water inlet of the circulating water pool through a second circulating pipe.

5. The power plant circulating water softening treatment system according to claim 4, characterized in that: The first circulation pipe is connected to a first flow valve, and the second circulation pipe is connected to a second flow valve.

6. The power plant circulating water softening treatment system according to claim 1, characterized in that: The sludge outlet of the solid-liquid separation fluidized bed is connected to a first collecting tank, and the crystal outlet of the calcium sulfate crystallization reactor is connected to a second collecting tank.

7. The power plant circulating water softening treatment system according to claim 1, characterized in that: A liquid level monitoring device is provided in the circulating water pool to monitor the liquid level of the circulating water pool. The water outlet of the circulating water pool is connected to the power plant through a water pipe. A regulating valve is connected to the water pipe. The regulating valve is electrically connected to the liquid level monitoring device through a control device.

8. The power plant circulating water softening treatment system according to claim 7, characterized in that: A hardness meter is arranged in the circulating water pool, and the hardness meter is electrically connected to the regulating valve through the control device.

9. A method for softening circulating water in a power plant, characterized in that: The power plant circulating water softening treatment system according to any one of claims 1 to 8 comprises the following steps: Passing the circulating water in the circulating water pool into the crystallization granulation fluidized bed, adding crystal seeds and reagents into the crystallization granulation fluidized bed to react with calcium ions and magnesium ions in the circulating water, and then discharging the generated calcium carbonate after circulating crystallization, while passing the generated magnesium hydroxide precipitate and the treated circulating water into the solid-liquid separation fluidized bed; A flocculant is introduced into the solid-liquid separation fluidized bed to precipitate and flocculate magnesium hydroxide to form sludge particles, and then the sludge particles are discharged from the sludge outlet, and the circulating water from which the sludge is removed is introduced into a reverse osmosis membrane device; The reverse osmosis membrane device removes chloride ions and sulfate ions in the circulating water to obtain clean water and concentrated water mixed with chloride ions and sulfate ions, the clean water is returned to the circulating water pool, and the concentrated water is passed into the calcium sulfate crystallization reactor; Adding crystal seeds into the calcium sulfate crystallization reactor to induce calcium sulfate crystallization in the supersaturated concentrated water, softening the concentrated water, and returning the softened water to the circulating water pool.

10. The method for softening circulating water in a power plant according to claim 9, characterized in that: The medicament includes sodium hydroxide and sodium bicarbonate.

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