Treatment system for power plant wastewater recovery

Abstract

The invention discloses a treatment system for power plant wastewater recovery, which comprises a softening pretreatment assembly for removing impurities in wastewater, a clarification tank for treating suspended matters, a clean water tank for storing clean water, a membrane concentration assembly communicated with the softening pretreatment assembly, and a water supply assembly communicated with the membrane concentration assembly. The device is used for further improving the filtering effect on the wastewater and comprises a multi-medium filter for filtering impurities and a reverse osmosis device for desalting the wastewater. The power plant wastewater treatment system has the beneficial effects that some solid impurities in power plant wastewater can be filtered through the softening pretreatment assembly, the crystallization phenomenon in an existing wastewater treatment system is greatly reduced, the treated wastewater can be further filtered through the membrane concentration assembly, salt in the wastewater can be concentrated and separated, the discharge amount of strong brine is reduced, and the treatment cost is reduced. In addition, reverse osmosis produced water and reverse osmosis concentrated water produced by the reverse osmosis device can be respectively supplemented for boiler water and desulfurization water, so that the recycling rate of wastewater is increased.

Description

Technical Field

[0001] The present invention relates to the field of wastewater recovery, in particular to a treatment system for wastewater recovery in power plants. Background Art

[0002] With the development of the national economy, my country is facing increasingly severe challenges such as water shortages, severe water source pollution, and low sewage and wastewater reuse rates. The continuous expansion of industrial production has also led to a rapid increase in industrial water consumption and wastewater production. Currently, membrane water treatment processes are widely used as a mainstream technology for boiler feed water treatment systems at water sources and zero-discharge industrial wastewater systems. However, existing membrane water treatment systems suffer from the problem of crystallization and precipitation, and overall low recovery rates. In response to this, we propose a treatment system for power plant wastewater recycling. Summary of the Invention

[0003] Therefore, the technical problem to be solved by the present invention is that the existing membrane water treatment system has the problems of easy crystallization and precipitation and low overall recovery rate.

[0004] In order to solve the above technical problems, the present invention provides the following technical solutions: a treatment system for power plant wastewater recovery, which includes a softening pretreatment component for removing impurities in the wastewater, including a clarification tank for treating suspended matter and a clear water tank for storing clear water, and the clarification tank and the clear water tank are interconnected, a membrane concentration component is connected to the softening pretreatment component, and is used to further improve the filtering effect of the wastewater, including a multi-media filter for filtering impurities and a reverse osmosis device for desalting the wastewater.

[0005] As a preferred solution of a power plant wastewater recycling treatment system of the present invention, the clarification tank includes a coagulation tank, a flocculation tank and a sedimentation tank, the coagulation tank, the flocculation tank and the sedimentation tank are interconnected, the coagulation tank and the flocculation tank can gather large particles of impurities, and the sedimentation tank can precipitate the large particles of impurities gathered in the coagulation tank and the flocculation tank.

[0006] As a preferred solution of the power plant wastewater recycling treatment system of the present invention, drugs for aggregating particles in the coagulation tank and the flocculation tank are added to the coagulation tank and the flocculation tank.

[0007] As a preferred solution of the power plant wastewater recycling treatment system of the present invention, the coagulation tank and the flocculation tank are further provided with stirring equipment to improve the efficiency of particle aggregation.

[0008] As a preferred solution of the power plant wastewater recycling treatment system of the present invention, the upper part of the sedimentation tank is connected to the clear water tank, and the bottom of the sedimentation tank is provided with a reflux connected to the flocculation tank, and the bottom of the sedimentation tank is also connected to a buffer tank.

[0009] As a preferred solution of the power plant wastewater recycling treatment system of the present invention, the buffer tank can receive the sediment discharged from the bottom of the sedimentation tank.

[0010] As a preferred solution of a power plant wastewater recycling treatment system of the present invention, the membrane concentration component also includes a self-cleaning filter and an ultrafiltration device arranged between the multimedia filter and the reverse osmosis device, and the self-cleaning filter and the ultrafiltration device are both interconnected with the multimedia filter and the reverse osmosis device.

[0011] As a preferred solution of the power plant wastewater recycling treatment system of the present invention, the self-cleaning filter can further filter small particle impurities in the wastewater and clean the self-cleaning filter itself, and the ultrafiltration device can remove colloids, bacteria, viruses and other microorganisms in the water.

[0012] As a preferred solution of the power plant wastewater recycling treatment system of the present invention, the upper portion of the reverse osmosis device is connected to an ultrafiltration water supply tank, and the lower portion is connected to a desulfurization process water tank.

[0013] As a preferred solution of the power plant wastewater recycling treatment system of the present invention, the ultrafiltration water supply tank can be used for boiler water replenishment, and the desulfurization process water tank can temporarily store the wastewater to be desulfurized.

[0014] The beneficial effects of the power plant wastewater recycling treatment system of the present invention are as follows: some solid impurities in the power plant wastewater can be filtered through the softening pretreatment component, which greatly reduces the crystallization phenomenon in the existing wastewater treatment system; the membrane concentration component can further filter the treated wastewater and concentrate and separate the salt therein, reduce the discharge of concentrated brine, and reduce pollution to the environment; in addition, the reverse osmosis product water and reverse osmosis concentrated water produced by the reverse osmosis device can be used to supplement boiler water and desulfurization water respectively, thereby improving the wastewater recycling rate; in addition, part of the sludge at the bottom of the sedimentation tank is returned to the flocculation tank through the sludge return pump, and the other part of the sludge is transported to the buffer tank through the sludge circulation pump. In this way, part of the sludge is recycled within the system, reducing the amount of sludge that ultimately needs to be treated, thereby reducing the cost of sludge treatment and reducing the impact on the environment; and the sludge returned to the flocculation tank can provide more adsorption sites and bridging points, so the sludge return can reduce the amount of flocculant used and reduce the flocculation cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings of the embodiments of the present invention. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention. Among them:

[0016] Figure 1Shows a schematic diagram of the process structure of the softening pretreatment component in the invention;

[0017] Figure 2 The figure shows the process structure diagram of the membrane concentration component in the invention.

[0018] 1. Softening pretreatment component; 11. Clarification tank; 111. Coagulation tank; 112. Flocculation tank; 113. Sedimentation tank; 114. Buffer tank; 115. Return line; 12. Clear water tank; 2. Membrane concentration component; 21. Multi-media filter; 22. Self-cleaning filter; 23. Ultrafiltration device; 24. Reverse osmosis device; 25. Ultrafiltration water supply tank; 26. Desulfurization process water tank. DETAILED DESCRIPTION

[0019] In order to enable those skilled in the art to better understand the present invention, the present invention is further described in detail below with reference to specific embodiments and the accompanying drawings.

[0020] The terms used in the present invention are those commonly used in the art in view of the functions of the present invention, but these terms may vary according to the intentions of those skilled in the art, precedents, or new technologies in the art. In addition, specific terms may be selected by the applicant, and in such cases, their detailed meanings will be described in the detailed description of the present invention. Therefore, the terms used in the specification should not be understood as simple names, but rather as the meanings of the terms and the overall description of the present invention.

[0021] This embodiment provides a power plant wastewater recycling treatment system, such as Figure 1 As shown, it includes a softening pretreatment component 1 and a membrane concentration component 2, wherein the softening pretreatment component 1 can filter some solid impurities in the power plant wastewater, greatly reducing the crystallization phenomenon in the existing wastewater treatment system, and the membrane concentration component 2 can further filter the treated wastewater and concentrate and separate the salt therein, reducing the discharge of concentrated brine and reducing pollution to the environment.

[0022] from Figure 1As can be seen from the figure, the clarification tank 11 includes a coagulation tank 111, a flocculation tank 112 and a sedimentation tank 113. In the actual treatment process of power plant wastewater, the power plant wastewater will first be put into the coagulation tank 111. Because the coagulation tank 111 is equipped with a dosing device, the staff can put a coagulant into the coagulation tank 111 to make the fine particles and soluble substances in the wastewater aggregate into larger particles. Because the colloidal particles in the wastewater usually have a negative charge, these particles are difficult to aggregate due to electrostatic repulsion. The cations in the coagulant can neutralize the negative charges on the surface of the colloidal particles, reducing the electrostatic repulsion between the particles and allowing the particles to aggregate. However, the aggregated particles remain small and require further aggregation to facilitate precipitation. Therefore, after a period of coagulation, the wastewater in coagulation tank 111 is discharged into flocculation tank 112. At this time, the staff can use the dosing equipment in flocculation tank 112 to add flocculants to the wastewater in flocculation tank 112. The flocculant will coagulate the particles in the wastewater into larger flocs. Because flocculants are generally high-molecular polymers with long molecular chains, these molecular chains can bridge multiple tiny particles, forming larger flocs. In addition, stirring equipment can be installed in coagulation tank 111 and flocculation tank 112 to accelerate the reaction rate between the wastewater and the coagulant and flocculant, increasing the rate of production of large particles. During the flocculation process, particles need to collide with each other to aggregate and form larger flocs. Stirring uses mechanical motion to continuously move particles in the solution, increasing the chance of collision between particles. More collision opportunities make it easier for particles to aggregate, accelerating floc formation and improving flocculation efficiency. Furthermore, stirring ensures even distribution of the flocculant throughout the wastewater. Because flocculants require full contact with wastewater particles to be effective, stirring evenly disperses the flocculant throughout the wastewater, ensuring that every particle comes into contact with the flocculant. Consequently, evenly distributed flocculant binds more effectively to particles, forming larger flocs and enhancing flocculation effectiveness.

[0023] The flocs carried by the sewage into the sedimentation tank 113 will slowly fall in the sedimentation tank 113 under the action of its own gravity, forming sludge at the bottom of the sedimentation tank 113, thus achieving solid-liquid separation. Figure 1 As shown, the bottom of the sedimentation tank 113 is connected to a buffer tank 114. The staff can set a sludge circulation pump at the bottom of the sedimentation tank 113 to guide the sludge in the sedimentation tank 113 into the buffer tank 114, and finally transport it to the desulfurization absorption tower for solidification treatment through the filter cloth dehydrator.

[0024] In addition, from Figure 1It can also be seen that a return line 115 is provided at the bottom of the sedimentation tank 113, connecting to the flocculation tank 112. A sludge return pump can be installed here to direct some sludge into the flocculation tank 112, thereby increasing the particle concentration in the flocculation tank 112. Under the action of the flocculant, these particles are more likely to combine with other particles to form larger flocs, which helps improve sedimentation efficiency. In addition, the sludge comes into contact with fine particles in the wastewater in the flocculation tank 112, providing more adsorption sites and enhancing the flocculation effect. Therefore, by providing more adsorption sites and bridging points, sludge return can reduce the amount of flocculant used and lower flocculation costs. In addition, the sludge return pump returns part of the sludge at the bottom of the sedimentation tank 113 to the flocculation tank 112, while the remaining sludge is transported to the buffer tank 114 via the sludge circulation pump. In this way, part of the sludge is recycled within the system, reducing the amount of sludge that ultimately needs to be treated, thereby reducing sludge treatment costs and minimizing environmental impact.

[0025] After sedimentation is completed, the upper layer of clear water in the sedimentation tank 113 will flow into the clear water tank 12 through the pipeline. Through the buffering effect of the clear water tank 12, the water quality can be made more stable, reducing the impact of water quality fluctuations on the subsequent treatment system. In addition, the pH value of the water in the clear water tank 12 can also be adjusted to ensure the stability of the water quality entering the membrane concentration component 2, reduce the burden on the subsequent treatment system, and ensure the efficient operation of the entire system.

[0026] like Figure 1 As shown, to prevent residual suspended matter in the incoming water from entering the ultrafiltration unit 23 and reverse osmosis unit 24 and causing blockage, the present invention installs a multi-media filter 21 between the membrane concentration assembly 2 and the softening pretreatment assembly 1. The internal filler of the multi-media filter 21 is quartz sand (30 cm in the lower portion) and ceramsite (100 cm in the upper portion). When the clean water is transported through the multi-media filter 21 to the other components of the membrane concentration assembly 2 for treatment, the frequency of membrane cleaning can be reduced. A self-cleaning filter 22, located between the ultrafiltration unit 23 and the multi-media filter 21, further removes fine particles, ensuring stable system operation. Furthermore, multiple backwash pumps are installed on the self-cleaning filter 22. When the inlet and outlet water pressure differential or the operating time of the self-cleaning filter 22 exceeds a set value, they automatically activate to flush dirt from the filter screen. The membrane elements in the ultrafiltration unit 23 are all externally pressurized hollow fiber membranes, which can remove colloids, bacteria, viruses, and other microorganisms from the water, further improving the water quality of the power plant wastewater.

[0027] The wastewater treated by the ultrafiltration device 23 will enter the reverse osmosis device 24 connected to the ultrafiltration device 23. Under the action of the reverse osmosis device 24, water molecules pass through the membrane, while soluble salts and other impurities are retained, thereby dividing it into reverse osmosis produced water after most of the soluble salts and impurities are removed and reverse osmosis concentrated water containing a higher concentration of soluble salts and impurities. The reverse osmosis produced water can enter the ultrafiltration water supply tank 25 connected to the reverse osmosis device 24 and be used as boiler feed water or other industrial water. Because the water quality of the reverse osmosis produced water is pure, it can effectively prevent boiler scaling and extend the service life of the boiler. The reverse osmosis concentrated water will enter the desulfurization process water tank connected to the reverse osmosis device 24 as make-up water for the desulfurization absorption tower, reducing the water consumption of the desulfurization system.

[0028] Finally, it should be pointed out that the methods and devices described in detail above are merely embodiments, and those skilled in the art can modify these embodiments in different ways without departing from the scope of the present invention.

Claims

1. A power plant wastewater recovery treatment system, characterized by: include, A softening pretreatment component (1) is used to remove impurities in wastewater, comprising a clarifier (11) for treating suspended matter and a clear water tank (12) for storing clear water, wherein the clarifier (11) and the clear water tank (12) are interconnected; The membrane concentration component (2) is connected to the softening pretreatment component (1) and is used to further improve the filtering effect of the wastewater. It includes a multi-media filter (21) for filtering impurities and a reverse osmosis device (24) for desalination of the wastewater.

2. A power plant wastewater recycling system according to claim 1, characterized in that: The clarification tank (11) includes a coagulation tank (111), a flocculation tank (112) and a sedimentation tank (113). The coagulation tank (111), the flocculation tank (112) and the sedimentation tank (113) are interconnected. The coagulation tank (111) and the flocculation tank (112) can gather large particles of impurities, and the sedimentation tank (113) can precipitate the large particles of impurities gathered in the coagulation tank (111) and the flocculation tank (112).

3. A power plant wastewater recycling system according to claim 2, characterized in that: Medicines for aggregating particles in the coagulation tank (111) and the flocculation tank (112) are added to the coagulation tank (111) and the flocculation tank (112).

4. A power plant wastewater recycling system according to claim 3, characterized in that: The coagulation tank (111) and the flocculation tank (112) are also provided with stirring equipment to improve the efficiency of particle aggregation.

5. A power plant wastewater recycling system according to claim 4, characterized in that: The upper portion of the sedimentation tank (113) is connected to the clear water tank (12), and a return pipe (115) connected to the flocculation tank (112) is provided at the bottom of the sedimentation tank. The bottom of the sedimentation tank (113) is also connected to a buffer tank (114).

6. A power plant wastewater recycling system according to claim 5, characterized in that: The buffer tank (114) can receive sediment discharged from the bottom of the sedimentation tank (113).

7. The power plant wastewater recycling system according to claim 1, characterized in that: The membrane concentration assembly (2) further comprises a self-cleaning filter (22) and an ultrafiltration device (23) arranged between the multi-media filter (21) and the reverse osmosis device (24), and the self-cleaning filter (22) and the ultrafiltration device (23) are both in communication with the multi-media filter (21) and the reverse osmosis device (24).

8. A power plant wastewater recycling system according to claim 7, characterized in that: The self-cleaning filter (22) can further filter small particle impurities in the wastewater and perform a cleaning operation on the self-cleaning filter (22) itself, and the ultrafiltration device (23) can remove microorganisms such as colloids, bacteria, viruses, etc. in the water.

9. A power plant wastewater recycling system according to claim 8, characterized in that: The reverse osmosis device (24) is connected to an ultrafiltration water supply tank (25) at its upper portion and to a desulfurization process water tank (26) at its lower portion.

10. A power plant wastewater recycling system according to claim 9, characterized in that: The ultrafiltration water supply tank (25) can be used to replenish boiler water, and the desulfurization process water tank can temporarily store reverse osmosis concentrated water.

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