A wastewater reuse system for thermal power plants and its treatment process

Abstract

This invention discloses a wastewater reuse system and its treatment process for a thermal power plant. The wastewater reuse system includes a deep water-saving subsystem and a zero-discharge end-of-pipe wastewater subsystem. The deep water-saving subsystem includes a water treatment system drainage water-saving system, a slag water system drainage water-saving system, a domestic sewage treatment and drainage water-saving system, a routine and non-routine drainage system, an industrial wastewater treatment system, and a coal conveying water system. The zero-discharge end-of-pipe wastewater treatment process employs low-temperature multi-effect volume reduction and high-temperature bypass flue gas evaporation technology. This invention's deep water-saving subsystem enables cascaded utilization of wastewater throughout the plant, solving the problem of high-quality water being underutilized, and reducing fresh water intake and end-of-pipe wastewater discharge. After deep water-saving renovation, the zero-discharge end-of-pipe wastewater system is used to concentrate the wastewater, ultimately achieving zero wastewater discharge for the entire plant.

Description

Technical Field

[0001] This invention relates to the field of environmental governance technology, specifically to a wastewater reuse system for thermal power plants and its treatment process. Background Technology

[0002] Currently, most domestic thermal power plants face problems such as a low proportion of wastewater reuse and a large volume of wastewater increasing the difficulty of treatment. Summary of the Invention

[0003] The purpose of this invention is to provide a wastewater reuse system for thermal power plants and its treatment process to solve the problems existing in the prior art.

[0004] To achieve the above objectives, the technical solution of the present invention provides a wastewater reuse system for thermal power plants. The thermal power plant is equipped with a water supply system, a water treatment system, a circulating water system, a slag water system, a domestic sewage treatment system, and a coal-containing wastewater treatment system, including a deep water-saving subsystem and a zero-discharge end-of-pipe wastewater subsystem.

[0005] The deep water-saving subsystem includes a water treatment system drainage water-saving system, a slag water system drainage water-saving system, a domestic sewage treatment and drainage water-saving system, a regular and non-regular drainage system, an industrial wastewater treatment system, and a coal conveying water system; the terminal wastewater zero-discharge subsystem includes an equalization tank, a triple-effect evaporator, a heat source generator, a spray dryer, and several water pumps; the wastewater to be treated is pumped to the equalization tank, and then pumped to the triple-effect evaporator; the heat source generator system is installed on the boiler flue of the generator set, and the spray dryer is a dual-fluid atomizing dryer.

[0006] Furthermore, the steam condensate from the triple-effect evaporator is pumped to the clean water tank of the industrial wastewater treatment unit via a recovery water pump; the heat exchange tubes and fins of the heat source generator are made of ND steel, and the shell is made of carbon steel; the dual-fluid atomizing dryer includes a drying tower, dual-fluid nozzles, a high-temperature bypass flue, and a flue gas distributor; the ratio of the high-temperature bypass flue and the flue gas distributor to the number of units is 1:2, and the steam condensate from the triple-effect evaporator is pumped to the industrial wastewater treatment unit via a recovery water pump.

[0007] Furthermore, the water treatment system drainage water-saving system includes a high-salinity wastewater tank, a low-salinity wastewater tank, and several wastewater transfer pumps; the domestic sewage treatment and drainage water-saving system includes a collection tank, a domestic sewage treatment system, reuse pipelines, and water pumps; the industrial wastewater treatment system includes an emergency water tank, a low-salinity wastewater storage tank, a high-salinity wastewater storage tank, and an industrial wastewater treatment unit, wherein the wastewater in the low-salinity wastewater storage tank is treated by the industrial water treatment system and then transported through pipelines to the wastewater reuse tank of the coal conveying water system; the industrial wastewater treatment unit includes an oxidation reaction tank, a pH adjustment tank, a mixing tank, an inclined plate clarifier, a neutralization tank, a clear water tank, and a sludge thickening tank.

[0008] Furthermore, the slag water system drainage water-saving system includes an automatic water replenishment control valve, a slag water tank, a level gauge, a slag water pit, and a slag water pump; the automatic water replenishment control valve is installed in the slag water tank, the overflow water from the slag water tank flows into the slag water pit, and the overflow water is sent back to the slag water tank by the slag water pump, and the excess slag water and the overflow water from the water seal tank are sent to the coal-containing wastewater treatment system.

[0009] Furthermore, the coal conveying water system includes a rainwater sedimentation tank, a wastewater reuse tank, and a coal yard spray water network; the wastewater reuse tank is used to store overflow water from the slag pit and water seal trough, drainage from the side filtration system, and water produced by the industrial wastewater system; the coal yard spray water network includes a spray water network and high-pressure water spray.

[0010] This invention also discloses a wastewater reuse treatment process for thermal power plants based on the above-mentioned wastewater reuse system, including a deep water-saving treatment step and a terminal wastewater zero-discharge treatment step. The deep water-saving treatment step includes the following: S1, backwash and forward wash wastewater generated during the regeneration operation of the cation exchanger and anion exchanger in the power plant's water treatment system are transported to a low-salt wastewater tank via drainage pipes; acid-base replacement regeneration wastewater is transported to a high-salt wastewater tank via drainage pipes; forward wash wastewater generated during the regeneration operation of the mixed ion exchanger is transported to a low-salt wastewater tank via drainage pipes; backwash wastewater and acid-base replacement wastewater... The recycled waste liquid is transported to a high-salinity wastewater tank through drainage pipes; the high-salinity wastewater tank and the low-salinity wastewater tank are respectively transported to the low-salinity wastewater storage tank and the high-salinity wastewater storage tank of the industrial wastewater treatment system; S2, the automatic water replenishment control valve of the slag water system drainage water-saving system automatically adjusts the valve opening according to the liquid level of the slag water tank to control the water replenishment volume. The overflow water of the slag water tank is collected in the slag water pit and sent back to the slag water tank through the original slag water pump. Excess slag water and overflow water from the water seal tank are sent to the coal-containing wastewater treatment system; the water source for the slag water system is the unit circulating water return water; S3, domestic sewage enters After entering the collection tank, the wastewater is treated by the domestic sewage treatment system. The treated water is then used for greening and road spraying via reuse pipelines and pumps. S4, the wastewater in the low-salinity wastewater storage tank of the industrial wastewater treatment system is treated by the industrial water treatment system and then transported via pipeline to the wastewater reuse tank of the coal conveying water system. The industrial water treatment system includes the following processes: industrial wastewater is pumped from the wastewater storage tank to the oxidation reaction tank. Sodium hypochlorite is added to the oxidation reaction tank to reduce some of the organic matter content in the wastewater. Subsequently, the wastewater flows sequentially through the pH adjustment tank, mixing tank, inclined plate clarifier, and neutralization tank. HCl or NaOH is added to the adjustment tank to adjust the pH of the wastewater. Flocculants and coagulants are added to the mixing tank to accelerate the sedimentation of suspended solids. Acids and alkalis are added to the neutralization tank until the pH of the wastewater reaches 6-9. S5. The wastewater reuse tank of the coal conveying water system is used to store overflow water from the slag water pit and water seal tank, drainage from the side filtration system, and water produced by the industrial wastewater system. When the wastewater reuse tank is insufficient as a source of water for spraying the coal conveying water system, rainwater that has been settled and clarified in the rainwater sedimentation tank is used to supplement it. The terminal wastewater zero discharge treatment process adopts low temperature multi-effect volume reduction and high temperature bypass flue gas evaporation process.

[0011] Furthermore, the terminal wastewater zero-discharge treatment process specifically includes the following: the wastewater to be treated is pumped to the equalization tank, and then pumped to the triple-effect evaporator by the feed pump. When the concentrated material in the triple-effect evaporator reaches the design concentration, the liquid is pumped to the spray dryer for solidification. The heat source generator system is installed on the boiler flue of the generator set. It uses the heat of the flue gas in the flue to heat the medium in the heat source generator system to 90°C steam under vacuum conditions, and sends the steam to the triple-effect evaporator to evaporate and concentrate the wastewater.

[0012] This invention utilizes advanced water-saving subsystems, including the renovation of the water treatment system, slag water system, and domestic sewage treatment system, to achieve cascaded utilization of wastewater throughout the plant, solving the problem of high-quality water being underutilized and reducing the amount of fresh water intake and end-of-pipe wastewater discharge. After the advanced water-saving renovation, the end-of-pipe wastewater is concentrated using a zero-discharge subsystem, ultimately achieving zero wastewater discharge throughout the plant.

[0013] To make the concept, other objects, advantages, features and functions of the present invention clearer and easier to understand, preferred embodiments will be described in detail below in conjunction with the accompanying drawings. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the overall solution of the present invention.

[0016] Figure 2 This is a schematic diagram of the water-saving drainage system of the present invention.

[0017] Figure 3 This is a schematic diagram of the wastewater drainage and water-saving system of the present invention.

[0018] Figure 4 This is a schematic diagram of the wastewater treatment system drainage water-saving system of the present invention.

[0019] Figure 5 This is a schematic diagram of the industrial wastewater treatment system of the present invention.

[0020] Figure 6 This is a schematic diagram of the coal conveying water system of the present invention.

[0021] Figure 7 This is a schematic diagram of the zero-discharge wastewater subsystem of the present invention.

[0022] Figure 8 This is a schematic diagram of the spray dryer in the terminal wastewater zero discharge subsystem of the present invention. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] As attached Figure 1 As shown, the wastewater reuse system for thermal power plants involved in this invention includes a deep water-saving subsystem 1 and a zero-discharge end-of-pipe wastewater subsystem 2.

[0025] Thermal power plants are generally equipped with necessary water systems such as water supply system, water treatment system, circulating water system, slag water system, domestic sewage treatment system, and coal-containing wastewater treatment system.

[0026] The deep water-saving subsystem 1 includes a water treatment system drainage water-saving system 11, a slag water system drainage water-saving system 13, a domestic sewage treatment and drainage water-saving system 14, an industrial wastewater treatment system 16, and a coal conveying water system 12.

[0027] As attached Figure 2 As shown, the power plant's water treatment system H is used to treat water quality and generally includes devices such as filter beds, filters, cation exchangers H1, anion exchangers H2, and mixed ion exchangers H3. The wastewater from the water treatment system comes from various units of the system. Among them, the desalination processes such as cation exchangers, anion exchangers, and mixed ion exchangers generate a large amount of regeneration wastewater, which puts great pressure on the subsequent terminal wastewater zero-discharge subsystem.

[0028] The water treatment system drainage water-saving system 11 includes a high-salinity wastewater tank 111, a low-salinity wastewater tank 112, and several wastewater transfer pumps 113.

[0029] The backwash and forward wash wastewater generated during the regeneration operations of cation exchanger H1 and anion exchanger H2 are transported to low-salt wastewater tank 112 via drainage pipes, while the acid-base replacement regeneration wastewater is transported to high-salt wastewater tank 111 via drainage pipes.

[0030] The forward wash wastewater generated during the regeneration operation of the mixed ion exchanger H3 is transported to the low-salt wastewater tank 112 through the drainage pipe, while the backwash wastewater and acid-base replacement regeneration waste liquid are transported to the high-salt wastewater tank 111 through the drainage pipe.

[0031] The high-salinity wastewater tank 111 and the low-salinity wastewater tank 112 are respectively transported to the next process via wastewater transfer pump 113. Specifically, the high-salinity wastewater tank 111 and the low-salinity wastewater tank 112 are respectively transported to the low-salinity wastewater storage tank 162 and the high-salinity wastewater storage tank 163 of the industrial wastewater treatment system 16.

[0032] The high-salinity wastewater tank 111 and low-salinity wastewater tank 112 are also equipped with conventional necessary accessories in the fields of liquid level switch, flow meter, pipeline pressure gauge, check valve, gate valve, and valve.

[0033] As attached Figure 3 As shown, the slag removal methods for thermal power plant generator units generally include wet scraper slag removers and air-cooled dry slag discharge. For wet scraper slag removers, the water source is typically industrial water, and the water supply method is relatively crude. The water supply valve is constantly open, and when the water level in the pool is too high, slag-water overflow occurs. Because the water supply valve of the slag remover is manually operated and lacks automatic flow regulation, the water supply volume during operation far exceeds the loss, resulting in a large amount of water overflowing from the system. Although the overflow volume can be reduced to some extent by frequently adjusting the water supply volume manually, this involves high labor intensity and poses personal safety risks. Air-cooled dry slag discharge generally does not have a slag-free water system, but there is overflow water from a water seal trough at the bottom of the furnace.

[0034] The wastewater system drainage water-saving system 13 includes an automatic water supply control valve 131, a wastewater tank 130, a level gauge 132, and a wastewater pit 133.

[0035] The automatic water replenishment control valve automatically adjusts the valve opening according to the liquid level in the slag water tank to control the amount of water replenished. The overflow water from the slag water tank is collected in the slag water pit and sent back to the slag water tank through the original slag water pump. Excess slag water and overflow water from the water seal tank are sent to the coal-containing wastewater treatment system.

[0036] Furthermore, the slag water system's makeup water source is the unit's circulating water return water.

[0037] As attached Figure 4 As shown, the main sources of domestic sewage in thermal power plants are non-production wastewater from the plant area, which is currently mostly discharged into the sewer system and periodically pumped out by vacuum trucks or discharged through the municipal sewage network. In addition, there is a common problem of domestic sewage mixing with other sewage in some older plant areas.

[0038] The domestic sewage treatment and drainage water-saving system 14 includes a collection tank 141, a domestic sewage treatment system 142, and a reuse pipeline and water pump 143.

[0039] Among them, the domestic sewage treatment system 142 is a commonly used treatment system in the field, which generally includes a sedimentation treatment area, an anaerobic treatment area, an aerobic treatment area, and a disinfection treatment area.

[0040] The reused pipeline and water pump 143 are mainly used for greening spraying and road spraying; considering rainy days and special circumstances, an emergency discharge valve is installed in the low salinity wastewater storage tank of the industrial wastewater treatment system. When the water volume is insufficient to absorb the wastewater, it will be discharged into the low salinity wastewater storage tank 162 of the industrial wastewater treatment system 16.

[0041] Process wastewater from thermal power plants generally includes high-salinity wastewater and low-salinity wastewater. High-salinity wastewater mainly originates from desulfurization wastewater, fine treatment regeneration wastewater, and water treatment system regeneration wastewater (high-salinity portion), which is difficult to reuse. Low-salinity wastewater mainly originates from ammonia area influent (0.2 m³ / h), volatile gas absorber drainage (0.9 m³ / h), water treatment system drainage (6.4 m³ / h, low-salinity portion), and domestic sewage system wastewater produced during the rainy season. The main pollutants are pH and suspended solids. It can be recycled through simple acid-base adjustment, flocculation sedimentation, and clarification. The overall water quality is relatively good and it can be used as forebay makeup water.

[0042] As attached Figure 5 As shown, the industrial wastewater treatment system 16 includes an emergency water tank 161, a low-salinity wastewater storage tank 162, a high-salinity wastewater storage tank 163, and an industrial wastewater treatment unit 164.

[0043] The wastewater in the low-salinity wastewater storage tank 162 is treated by the industrial water treatment system 164 and then transported through pipelines to the wastewater reuse tank 122 of the coal conveying water system 12.

[0044] The industrial wastewater treatment unit 164 of this application includes an oxidation reaction tank, a pH adjustment tank, a mixing tank, an inclined plate clarifier, a neutralization tank, a clear water tank, and a sludge thickening tank. Industrial wastewater is pumped from the wastewater storage tank to the oxidation reaction tank. Sodium hypochlorite is added to the oxidation reaction tank to reduce the organic matter content in the wastewater. Subsequently, the wastewater flows sequentially through the pH adjustment tank, the mixing tank, the inclined plate clarifier, and the neutralization tank. HCl or NaOH is added to the pH adjustment tank to adjust the pH of the wastewater. Flocculants and coagulants are added to the mixing tank to accelerate the sedimentation of suspended solids. Acids and alkalis are added to the neutralization tank. When the pH of the wastewater reaches 6-9, it is discharged into the wastewater buffer tank of the domestic sewage system as flushing water for the machine room / ash storage.

[0045] The industrial wastewater treatment unit 164 can also be used for other wastewater treatment systems in the field.

[0046] For coal-fired power plants, to meet the relevant requirements for dust suppression in the coal yard, it is necessary to spray water to increase the surface humidity of coal dust (9%~10%). Taking the applicant as an example, the applicant's coal yard covers a total area of ​​45,400 square meters and stores 470,000 tons of coal. To achieve the desired dust suppression effect in the coal yard, 13.6 m³ of water is used daily. 3 / h. Currently, the water sources used for dust suppression spraying in coal yards mainly consist of rainwater and wastewater generated during power plant production processes (such as overflow water from slag water systems and overflow water from water seal tanks). Among these, rainwater is greatly affected by weather conditions.

[0047] As attached Figure 6 As shown, the coal conveying water system 12 includes a rainwater sedimentation tank 121, a wastewater reuse tank 122, and a coal yard spray water network 123.

[0048] Wastewater reuse pool 122 is used to store overflow water from slag pits and water seal tanks, drainage from side-filter systems, and water produced by industrial wastewater systems.

[0049] The coal yard sprinkler water network 123 includes a sprinkler water network and high-pressure water nozzles. The high-pressure water nozzles can rotate 180°, and the water mist from adjacent nozzles can be connected or overlapped, so that the water mist coverage in the coal yard reaches more than 90%.

[0050] Based on the above scheme, the water source for all 12 spraying systems in the coal conveying water system is wastewater, realizing the secondary utilization of sewage. Only when the above water source is insufficient will rainwater after sedimentation and clarification be used to supplement it. This reduces pollution at the source, achieves effective resource utilization, improves water resource utilization rate, and also achieves effective dust reduction in the coal yard. While increasing economic efficiency, it greatly reduces environmental pollution and generates good social and economic benefits.

[0051] Due to its characteristics, high-salinity wastewater from thermal power plants is difficult to reuse. Taking the applicant as an example, the main sources of high-salinity wastewater from Maoming Power Plant are: desulfurization wastewater, fine treatment regeneration wastewater, and water treatment regeneration wastewater (high-salinity portion), totaling 15 m³ / h. The main pollutant is salt (TDS ≥ 12000 mg / L), with high hardness. Using it for landscaping or ground washing causes soil salinization, affecting plant growth; using it as coal yard spray water results in chlorine re-evaporation during combustion, increasing the risk of corrosion at the boiler tail end, and sodium salts easily coke inside the furnace under high-temperature conditions; using it as makeup water for the slag remover easily corrodes the metal chains, and the makeup water volume for the slag remover is insufficient to completely absorb this high-salinity wastewater. Therefore, a new end-of-pipe zero-discharge wastewater subsystem is needed.

[0052] As attached Figure 7 As shown, the end-of-pipe wastewater zero discharge subsystem 2 of this application adopts a technical solution of low temperature multi-effect volume reduction and high temperature bypass flue gas evaporation, including a regulating tank 21, a triple-effect evaporator 22, a heat source generator 23, a spray dryer 24, and several water pumps 25.

[0053] The wastewater to be treated is pumped to the equalization tank 21, and then pumped to the primary secondary steam tank of the triple-effect evaporator 22 by a feed pump. The wastewater in the primary secondary steam tank is sent to the tube side of the primary heating tank by a primary forced circulation pump. Steam generated by the heat source generator 23 enters the shell side of the primary heating tank and exchanges heat with the wastewater entering the system. After being heated, the wastewater enters the primary secondary steam tank, where steam is generated and enters the shell side of the secondary heating tank. The wastewater in the primary secondary steam tank continues to circulate back into the primary heating tank to exchange heat with the steam. Due to the evaporation of water in the primary secondary steam tank, the slurry concentration increases. After multiple cycles within the first-effect system, the pre-concentrated liquid enters the secondary secondary steam tank under pressure differential. The material entering the second effect uses the same principle as in the first effect, utilizing the secondary steam generated in the primary secondary steam tank as the heat source for the subsequent second-effect evaporator, and undergoes forced circulation evaporation and concentration using a circulating pump. The concentrated liquid enters the third-stage secondary steam tank under pressure differential. The material entering the third-effect evaporator operates on the same principle as the first and second effects, utilizing the secondary steam generated in the second-stage secondary steam tank as the heat source for the third-effect evaporator, and undergoes forced circulation evaporation and concentration using a circulating pump. When the concentrated material in the third-effect evaporator 22 reaches the designed concentration, the liquid is pumped to the spray dryer 24 for solidification.

[0054] The condensate from the triple-effect evaporator 22 is pumped by a recovery water pump to the clean water tank of the industrial wastewater treatment unit 164.

[0055] The heat source generator system 23 is installed on the boiler flue of the generator set. It utilizes the heat from the flue gas in the flue to heat the medium within the heat source generator system 23 to ~90°C steam under vacuum conditions. This steam is then sent to a triple-effect evaporator 22 to evaporate and concentrate the wastewater. The condensed steam is collected in a condensate tank and then pumped back to the heat source generator via a single-effect condensate pump. The steam from the heat source generator system 23 can meet the energy requirements for zero-discharge wastewater treatment. After installing the heat source generator, the flue resistance increases by no more than 40 Pa.

[0056] The heat exchange tubes and fins of the heat source generator in this application are made of ND steel, and the shell is made of carbon steel. Each heat source generator has a resistance of about 50 Pa, which can reduce the flue gas temperature at the inlet of the absorption tower by about 5-8°C, thereby reducing the operating flow rate of the flue gas entering the absorption tower and reducing the resistance of the absorption tower. After adding the heat source generator, the total resistance of the flue gas system increases by about 40 Pa, which has a very small impact on the flue gas system.

[0057] As attached Figure 8As shown, the spray dryer 24 of this application is a dual-fluid atomizing dryer. It includes a drying tower 241, a dual-fluid nozzle 242, a high-temperature bypass flue, and a flue gas distributor 243. The dual-fluid nozzle 242 uses compressed air as the atomizing medium. The liquid passes through the central pipe and is finally sprayed out from the outlet. The compressed air passes through the spiral groove and is sprayed out from the air outlet, impacting the liquid droplets and forming atomization. Its atomization mechanism is: high-speed airflow directly acts on the liquid surface, causing it to break into fine atomized droplets. The high-temperature bypass flue and flue gas distributor 243 typically adopt a "slender and tall" high-temperature bypass flue evaporation atomization evaporation method, conventionally using a single-unit dual-tower design, with one unit equipped with two slender bypass flue spray dryers 24 (i.e., one spray dryer 24 corresponds to one side of the air preheater). In use, the high-temperature bypass flue and flue gas distributor 243 of the flue spray dryer 24 take flue gas from the air preheater of the boiler flue of the unit to evaporate and crystallize the wastewater after dual-fluid atomization.

[0058] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0059] It should be noted that, unless otherwise explicitly specified and limited, terms such as "installation," "connection," "joining," "fixing," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0060] Furthermore, it should be noted that in the description of this invention, the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this application. In the description of this invention, unless otherwise stated, "multiple" means two or more.

[0061] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A wastewater reuse system for a thermal power plant, wherein the thermal power plant is equipped with a water supply system, a water treatment system, a circulating water system, a slag water system, and a coal-containing wastewater treatment system, including a deep water-saving subsystem and a terminal wastewater zero-discharge subsystem; the deep water-saving subsystem includes a water treatment system drainage water-saving system, a slag water system drainage water-saving system, a domestic sewage treatment and drainage water-saving system, a regular and non-regular drainage system, an industrial wastewater treatment system, and a coal conveying water system; characterized in that, The terminal wastewater zero-discharge subsystem includes an equalization tank, a triple-effect evaporator, a heat source generator, a spray dryer, and several water pumps; the wastewater to be treated is pumped to the equalization tank and then pumped to the triple-effect evaporator. The heat source generator system is installed on the boiler flue of the generator set, and the spray dryer is a two-fluid atomizing dryer; the steam condensate from the triple-effect evaporator is transported to the clear water tank of the industrial wastewater treatment unit by a recovery water pump; the heat exchange tubes and fins of the heat source generator are made of ND steel, and the shell is made of carbon steel; the two-fluid atomizing dryer includes a drying tower, two-fluid nozzles, a high-temperature bypass flue, and a flue gas distributor; the ratio of the high-temperature bypass flue and the flue gas distributor to the number of units is 1:2, and the steam condensate from the triple-effect evaporator is transported to the industrial wastewater treatment unit by a recovery water pump. The water treatment system includes a high-salinity wastewater tank, a low-salinity wastewater tank, and several wastewater transfer pumps; the domestic sewage treatment and drainage water-saving system includes a collection tank, a domestic sewage treatment system, reuse pipelines, and pumps; the industrial wastewater treatment system includes an emergency water tank, a low-salinity wastewater storage tank, a high-salinity wastewater storage tank, and an industrial wastewater treatment unit, wherein the wastewater in the low-salinity wastewater storage tank is treated by the industrial water treatment system and then transported through pipelines to the wastewater reuse tank of the coal conveying water system; the industrial wastewater treatment unit includes an oxidation reaction tank, a pH adjustment tank, a mixing tank, an inclined plate clarifier, a neutralization tank, and a clear water tank. The sludge thickening tank; the wastewater drainage and water-saving system includes an automatic water supply control valve, a wastewater tank, a level gauge, a wastewater pit, and a wastewater pump; the automatic water supply control valve is installed in the wastewater tank, the overflow water from the wastewater tank flows into the wastewater pit, and the overflow water is sent back to the wastewater tank by the wastewater pump, and the excess wastewater and overflow water from the water seal tank are sent to the coal-containing wastewater treatment system; the coal conveying water system includes a rainwater sedimentation tank, a wastewater reuse tank, and a coal yard spray water network; the wastewater reuse tank is used to store overflow water from the wastewater pit and water seal tank, drainage from the side filtration system, and water produced by the industrial wastewater system; the coal yard spray water network includes a spray water network and high-pressure water spray.

2. A wastewater reuse treatment process for thermal power plants based on the wastewater reuse system of claim 1, characterized in that, It includes advanced water-saving treatment processes and end-of-pipe zero-discharge wastewater treatment processes, wherein the advanced water-saving treatment processes include the following: S1. The backwash and forward wash wastewater generated during the regeneration operation of the cation exchanger and anion exchanger in the power plant's water treatment system are transported to a low-salinity wastewater tank via drainage pipes. The acid-base replacement regeneration waste liquid is transported to a high-salinity wastewater tank via drainage pipes. The forward wash wastewater generated during the regeneration operation of the mixed ion exchanger is transported to a low-salinity wastewater tank via drainage pipes. The backwash wastewater and acid-base replacement regeneration waste liquid are transported to a high-salinity wastewater tank via drainage pipes. The high-salinity wastewater tank and the low-salinity wastewater tank are respectively transported to the high-salinity wastewater storage tank and the low-salinity wastewater storage tank of the industrial wastewater treatment system. S2. The automatic water supply control valve of the slag water system drainage and water-saving system automatically adjusts the valve opening according to the liquid level of the slag water tank to control the water supply volume. The overflow water of the slag water tank is collected in the slag water pit and sent back to the slag water tank through the original slag water pump. Excess slag water and overflow water from the water seal tank are sent to the coal-containing wastewater treatment system. The water supply source of the slag water system is the unit circulating water return water. S3. After entering the collection tank, domestic sewage is treated by the domestic sewage treatment system. The treated water is then used for greening and road spraying through reuse pipes and pumps. S4. Wastewater in the low-salinity wastewater storage tank of the industrial wastewater treatment system is treated by the industrial water treatment system and then transported through pipelines to the wastewater reuse tank of the coal conveying water system. The treatment process of the industrial water treatment system includes the following steps: Industrial wastewater is pumped from the wastewater storage tank to the oxidation reaction tank. Sodium hypochlorite is added to the oxidation reaction tank to reduce the organic matter content in the wastewater. Subsequently, the wastewater flows through the pH adjustment tank, mixing tank, inclined plate clarifier, and neutralization tank in sequence. HCl or NaOH is added to the pH adjustment tank to adjust the pH of the wastewater. Flocculants and coagulants are added to the mixing tank to accelerate the sedimentation of suspended solids. Acid and alkali agents are added to the neutralization tank until the pH value of the wastewater reaches 6-9. S5. The wastewater reuse pool of the coal conveying water system is used to store overflow water from the slag water pit and water seal trough, drainage from the side filter system, and water produced by the industrial wastewater system. When the wastewater reuse pool is insufficient as a source of water for spraying the coal conveying water system, rainwater that has been settled and clarified in the rainwater sedimentation tank is used to supplement it. The terminal wastewater zero-discharge treatment process adopts low-temperature multi-effect volume reduction and high-temperature bypass flue gas evaporation technology.

3. The wastewater reuse treatment process for thermal power plants according to claim 2, characterized in that, The terminal wastewater zero-discharge treatment process specifically includes the following: the wastewater to be treated is pumped to the equalization tank, and then pumped to the triple-effect evaporator by the feed pump. When the concentrated material in the triple-effect evaporator reaches the design concentration, the liquid is pumped to the spray dryer for solidification. The heat source generator system is installed on the boiler flue of the generator set. It uses the heat of the flue gas in the flue to heat the medium in the heat source generator system to 90°C steam under vacuum conditions, and sends the steam to the triple-effect evaporator to evaporate and concentrate the wastewater.

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