CN111423035A - A process system and method for combined treatment of circulating water in a thermal power plant without chemical and chemical methods - Google Patents

Abstract

The invention discloses a thermal power plant circulating water non-medicament electric method combined treatment process system and a method, wherein an outlet of a raw water tank is communicated with an inlet of a low-voltage electric descaling reactor, an outlet of the low-voltage electric descaling reactor is communicated with an inlet of an electric method concentration system through a multi-medium filter and a first intermediate water tank, a produced water outlet of the electric method concentration system is communicated with an inlet of a produced water tank through a second intermediate water tank, an electric method pH regulator and a manganese sand filter, an outlet of the produced water tank is communicated with an inlet of a cooling tower pool through a produced water pump, an outlet of the cooling tower pool is communicated with an inlet of the raw water tank, and a high-voltage electrostatic polarization device is arranged in the cooling tower pool.

Description

A process system and method for combined treatment of circulating water in a thermal power plant without chemical and chemical methods

technical field

The invention belongs to the field of circulating water treatment in thermal power plants, and relates to a process system and method for combined treatment of circulating water in thermal power plants with chemical-free electro-chemical methods.

Background technique

Circulating cooling power plants generally adopt the chemical dosing method of adding acid, adding water quality stabilizer and bactericide to achieve scale inhibition, corrosion inhibition and sterilization treatment of the circulating water system, and ensure the safe and stable operation of the circulating water system. However, there are many types of chemicals added in this method, which will cause secondary pollution to the water body; it is difficult to adjust the dosage of chemicals with the fluctuation of water quality and water volume. In order to ensure the safety of operation, most power plants use extensive over-dosing methods, resulting in high operating costs of chemicals. .

With the strict implementation of the sewage permit system, many thermal power plants use the coagulation clarification/softening pretreatment-membrane desalination system to treat and reuse the circulating water sewage. However, in actual operation, due to the residual chemicals in the circulating water and sewage, the coagulation clarification/softening pretreatment effect is not good, the flocs are small and light, the settling performance is poor, and the pool is easy to turn over, resulting in the subsequent ultrafiltration and reverse osmosis. Equipment is easily clogged.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art, and to provide a combined treatment process system and method for the chemical-free chemical treatment of circulating water in a thermal power plant. deal with.

In order to achieve the above-mentioned purpose, the chemical-free and chemical-electricity combined treatment process system for the circulating water of the thermal power plant according to the present invention comprises a raw water tank, a low-voltage electric descaling reactor, a multi-media filter, a first intermediate water tank, an electric concentration system, and a first intermediate water tank. Two intermediate water tanks, electrical pH regulators, manganese sand filters, production water tanks, production water pumps, cooling tower pools, waste water collection pools and desulfurization process water tanks;

The outlet of the raw water tank is communicated with the inlet of the low-voltage electric descaling reactor, and the outlet of the low-voltage electric descaling reactor is communicated with the inlet of the electric concentration system through the multi-media filter and the first intermediate water tank. The water outlet is connected with the inlet of the water production tank through the second intermediate water tank, the electrical pH regulator and the manganese sand filter, and the outlet of the water production tank is connected with the inlet of the cooling tower pool through the production water pump, and the outlet of the cooling tower pool is connected with the inlet of the cooling tower pool. The inlet of the raw water tank is connected, and a high-voltage electrostatic polarization device is arranged in the cooling tower pool.

The concentrated water outlet of the electric concentration system is communicated with the inlet of the waste water collection tank, and the outlet of the waste water collection pool is communicated with the inlet of the desulfurization process water tank.

The outlet of the first intermediate water tank is communicated with the backwash water inlet of the multi-media filter through the first backwash pump, and the backwash water outlet of the multi-media filter is communicated with the inlet of the waste water collection tank.

The raw water tank is communicated with the inlet of the low-voltage electric descaling reactor through the first inlet pump, and the washing waste water outlet of the low-pressure electric descaling reactor is communicated with the inlet of the waste water collection tank.

The bottom outlet of the first intermediate water tank is communicated with the tower pool of the cooling tower through a drainage pump.

The first intermediate water tank is communicated with the electric concentration system through the second inlet water pump.

The second intermediate water tank is communicated with the inlet of the electrical pH regulator through the third inlet water pump.

The cleaning wastewater outlet of the electrical pH regulator is communicated with the inlet of the wastewater collection tank.

The outlet of the water production tank is communicated with the backwash water inlet of the manganese sand filter through the second backwash pump, the backwash water outlet of the manganese sand filter is communicated with the inlet of the waste water collection pool, and the outlet of the waste water collection pool is connected with the waste water lift pump. Connected with the desulfurization process water tank.

The chemical-free chemical-electricity combined treatment process for circulating water in thermal power plants according to the present invention comprises the following steps:

1) The circulating water of the thermal power plant enters the raw water tank for buffering and homogenization, and then enters the low-voltage electric descaling reactor for electrolysis, alkalinity reduction and descaling treatment, and the output water from the low-voltage electric descaling reactor enters the multi-media filter. filter to remove suspended solids and reduce turbidity;

2) The water output by the multi-media filter enters the first intermediate water tank, and the water output from the first intermediate water tank is divided into two channels, one of which enters the cooling tower pool, and the other enters the electric concentration system for desalination treatment ;

3) The produced water output from the electrical concentration system enters the second intermediate water tank, and then enters the electrical pH regulator to adjust the pH value to below 7, and the water output from the electrical pH regulator enters the manganese sand filter. Filtration, the water output by the manganese sand filter enters the water production tank, the water output from the water production tank enters the cooling tower pool, and the water in the cooling tower pool is processed by the high-voltage electrostatic polarization device and then enters the raw water tank.

The present invention has the following beneficial effects:

In the specific operation, the chemical-free and chemical-electricity combined treatment process system and method for the circulating water of the thermal power plant of the present invention utilizes low-voltage electric scale removal, high-voltage electrostatic polarization and electric concentration combined treatment methods to realize the whole process of circulating water and sewage. Treatment to ensure the safe and stable operation of the circulating water system. Specifically, when the low-voltage electric descaling reactor and the high-voltage electrostatic polarization device are used to stabilize the circulating water quality, the descaling, anti-corrosion and sterilization efficiency is high, and no chemicals are added. It completely replaces the traditional chemical dosing treatment technology of circulating water, and at the same time, it can significantly reduce the difficulty of treatment and reuse of circulating water and sewage. In addition, the present invention adopts the electroconcentration system to desalinate the circulating water sewage, only needs to control the pH value and turbidity of the influent water, so as to avoid the poor pretreatment and sedimentation efficiency caused by the residual chemical agent in the circulating water sewage, and the subsequent membrane Components are prone to fouling and blocking and many other operational problems, effectively reducing investment, operating costs and difficulty in operation control. At the same time, the hypochlorite content in the water produced by the electroconcentration system increases, and it plays a sterilizing role after being reused in the cooling tower. Finally, the present invention uses an electrical pH regulator to replace the traditional acid addition to adjust pH, again avoiding the addition of chemicals, and at the same time, the cathode of the electrical pH regulator can deposit calcium and magnesium insoluble matter, and also has a certain desalination effect. Realize the whole process of zero chemical treatment of the circulating water system of the wet cooling unit.

Description of drawings

FIG. 1 is a schematic structural diagram of the present invention.

Among them, 1 is the original water tank, 2 is the first inlet pump, 3 is the low-voltage electric descaling reactor, 4 is the multi-media filter, 5 is the first intermediate water tank, 6 is the first backwash pump, and 7 is the second inlet Water pump, 8 is the drainage pump, 9 is the electric concentration system, 10 is the second intermediate water tank, 11 is the third inlet pump, 12 is the electric pH regulator, 13 is the manganese sand filter, 14 is the water production tank, and 15 is the The second backwash pump, 16 is a production water pump, 17 is a high-voltage electrostatic polarization device, 18 is a waste water collection tank, 19 is a waste water lifting pump, and 20 is a desulfurization process water tank.

Detailed ways

Below in conjunction with accompanying drawing, the present invention is described in further detail:

Referring to Fig. 1, the combined treatment process system of the thermal power plant's circulating water without chemicals and electricity includes a raw water tank 1, a low-voltage electric descaling reactor 3, a multi-media filter 4, a first intermediate water tank 5, an electric concentration System 9, second intermediate water tank 10, electrical pH regulator 12, manganese sand filter 13, product water tank 14, product water pump 16, cooling tower pool, waste water collection pool 18 and desulfurization process water tank 20; outlet of raw water tank 1 It is communicated with the inlet of the low-voltage electric descaling reactor 3, and the outlet of the low-voltage electric descaling reactor 3 is communicated with the inlet of the electric concentration system 9 through the multi-media filter 4 and the first intermediate water tank 5. The electric concentration system 9 The outlet of the produced water is communicated with the inlet of the water production tank 14 through the second intermediate water tank 10, the electrical pH regulator 12 and the manganese sand filter 13, and the outlet of the produced water tank 14 is communicated with the inlet of the cooling tower pool through the production water pump 16. , the outlet of the cooling tower pool is communicated with the inlet of the original water tank 1, the cooling tower pool is provided with a high-voltage electrostatic polarization device 17, the concentrated water outlet of the electrical concentration system 9 is communicated with the inlet of the waste water collection pool 18, and the waste water is collected. The outlet of the pool 18 communicates with the inlet of the desulfurization process water tank 20 .

It should be noted that the outlet of the first intermediate water tank 5 is communicated with the backwash water inlet of the multi-media filter 4 through the first backwash pump 6 , and the backwash water outlet of the multi-media filter 4 is connected to the inlet of the waste water collection tank 18 The raw water tank 1 is communicated with the inlet of the low-voltage electric descaling reactor 3 through the first inlet pump 2, and the cleaning waste water outlet of the low-voltage electric descaling reactor 3 is communicated with the inlet of the waste water collection tank 18; the first intermediate water tank The bottom outlet of 5 is communicated with the cooling tower pool through the drainage pump 8; the first intermediate water tank 5 is communicated with the electric method concentration system 9 through the second inlet water pump 7; the second intermediate water tank 10 is communicated with the electric method through the third inlet water pump 11. The inlet of the pH regulator 12 is connected; the outlet of the cleaning waste water of the electrical pH regulator 12 is connected with the inlet of the waste water collection tank 18; the outlet of the water production tank 14 is backwashed with the manganese sand filter 13 by the second backwash pump 15 The water inlet is communicated, the backwash water outlet of the manganese sand filter 13 is communicated with the inlet of the waste water collection pool 18, and the outlet of the waste water collection pool 18 is communicated with the desulfurization process water tank 20 through the waste water lift pump 19.

The chemical-free chemical-electricity combined treatment process for circulating water in thermal power plants according to the present invention comprises the following steps:

1) The circulating water of the thermal power plant enters the raw water tank 1 for buffering and homogenization, and then enters the low-voltage electric descaling reactor 3 for electrolysis, alkalinity reduction and descaling treatment. Filtration in media filter 4 to remove suspended solids and reduce turbidity;

It should be noted that the low-voltage electric descaling reactor 3 is provided with a metal composite electrode, which is connected to an external DC power supply. When the circulating water flows through the low-voltage electric field formed by the positive and negative electrodes, a large amount of OH will be generated near the cathode plate ^to form a strong alkaline environment. The cations such as calcium and magnesium in the water are attracted to the cathode plate and migrate to the cathode plate to form insoluble substances such as calcium carbonate and magnesium hydroxide, which are deposited on the cathode and play the role of descaling; the anode undergoes oxidation reaction to generate a large number of active substances such as ozone, chlorine and other substances. , play a bactericidal effect.

2) The water output by the multi-media filter 4 enters the first intermediate water tank 5, and the water output from the first intermediate water tank 5 is divided into two paths, one of which enters the cooling tower pool, and the other enters the electrical concentration system 9 desalination treatment;

The electric concentration system 9 is provided with a cylindrical electrode, an external DC power supply, and adopts a matrix grouping processing mode to adapt to different water volume and water quality requirements. When the electric concentration system 9 desalinates the circulating water sewage, it mainly uses the action of the electric field to make the oppositely charged ions in the solution move and adsorb to the electrode surface, so as to realize the removal of the ions in the circulating water sewage, and achieve desalination and purpose of purification. At the same time, the chloride ions in the sewage of the circulating water will be electrolyzed in a large amount near the anode of the electroconcentration system 9 to generate hypochlorous acid and free chlorine, etc. The produced water plays a sterilizing effect when it is reused to the cooling tower, and the electroconcentration system 9 can be assembled flexibly , according to the water quality requirements, multi-level settings can be carried out to achieve the designed desalination rate and recovery rate. Generally, the recovery rate of the electroconcentration system 9 is adjustable between 70% and 95%, and the desalination rate is adjustable between 40% and 90%.

3) The produced water output from the electrical concentration system 9 enters the second intermediate water tank 10, and then enters the electrical pH regulator 12 to adjust the pH value below 7, and the water output from the electrical pH regulator 12 enters the manganese sand. Filtration is carried out in the filter 13, the water output from the manganese sand filter 13 enters the water production tank 14, the water output from the water production tank 14 enters the cooling tower pool, and the water in the cooling tower pool passes through the high-voltage electrostatic polarization device 17. After treatment, it enters the raw water tank 1.

The high-voltage electrostatic polarization device 17 mainly uses the electrostatic field effect, that is, when the circulating water flows through the high-voltage electrostatic field formed by the positive and negative electrodes, the dipole moment of the water molecules will increase, forming polar water molecules, and interacting with Ca ²⁺ in the water. , Mg ²⁺ , CO ₃ ^2- , SO ₄ ^2- and Cl ^- and other positive and negative ions attract each other to produce hydration, making it unable to move freely, thereby preventing the formation of scale and slowing the corrosion of Cl ^- to the cathode wall, The high anti-scaling effect of the high-voltage electrostatic polarization device 17 provides the low-voltage electrical descaling reactor 3 with a high alkalinity circulating water quality environment, and promotes the formation of carbonate scale on the low-voltage electrical descaling reactor 3 .

With the extension of the running time, the low-voltage electric descaling reactor 3 and the electrical pH regulator 12 need to be descaled by the reverse pole, and washed with water from the raw water tank 1. At this time, the scale substances removed from the cathode surface will follow The flushing water is discharged, and the generated low-voltage electric descaling reactor 3 cleaning waste water is discharged to the waste water collection tank 18 .

After the electrodes of the electroconcentration system 9 are saturated with adsorption, the electrodes need to be regenerated by applying a reverse voltage, and the first intermediate water tank 5 is used for washing with water. At this time, the charged particles adsorbed by the positive and negative plates are released into the washing water, forming a The concentrated water is discharged to the waste water collection tank 18 .

When the multi-media filter 4 and the manganese sand filter 13 are backwashed, the backwash waste water produced is discharged to the waste water collection tank 18 .

The water output from the waste water collection tank 18 is finally discharged into the desulfurization process water tank 20 for use as supplementary water for the desulfurization system.

In order to avoid the above problems caused by the chemical treatment of circulating water, the circulating water treatment in the present invention adopts low-voltage electric descaling and high-voltage electrostatic polarization technology to ensure the descaling, corrosion inhibition and sterilization effects of the circulating water system; The electro-concentration technology is adopted, which has the combined functions of desalination and sterilization. At the same time, the quality of the influent water is low, and there is no need to set up a complex pretreatment system. It can also avoid the problem of membrane fouling and blockage caused by residual chemicals in the circulating water, and the desalination process does not add Any medicament will help reduce the difficulty of subsequent reuse of concentrated water.

The combination technology of low-voltage electric descaling, high-voltage electrostatic polarization and electric concentration is used in the circulating water system of thermal power plants. The process is simple, the adaptability to water quality is small, the area is small, the equipment is simple and easy to operate, and it can break through the traditional "chemical dosing". Due to the limitations of the "scale inhibition + membrane desalination of circulating water sewage" treatment technology, the unique advantages of low-voltage electric descaling, high-voltage electrostatic polarization, and electric concentration combined technology can realize the whole process of circulating water and circulating water sewage without chemicals. It can effectively reduce equipment investment and operating costs, and improve the economy of circulating water reuse and treatment.

Finally, it should be noted that the present invention has simple structure, strong adaptability to water quality, high efficiency of descaling, anticorrosion and sterilization, and the recovery rate and desalination rate of the electroconcentration system can be controlled by the flexible combination of equipment without adding any It is a green, environmentally friendly and efficient new technology for circulating water treatment in thermal power plants, which has good economic and environmental benefits.

Claims (9)

1. A thermal power plant circulating water non-medicament electric method combined treatment process system is characterized by comprising a raw water tank (1), a low-voltage electric descaling reactor (3), a multi-medium filter (4), a first middle water tank (5), an electric method concentration system (9), a second middle water tank (10), an electric method pH regulator (12), a manganese sand filter (13), a water production tank (14), a water production pump (16), a cooling tower pool, a waste water collecting pool (18) and a desulfurization process water tank (20);

an outlet of the raw water tank (1) is communicated with an inlet of a low-voltage electric descaling reactor (3), an outlet of the low-voltage electric descaling reactor (3) is communicated with an inlet of an electric method concentration system (9) through a multi-medium filter (4) and a first intermediate water tank (5), a produced water outlet of the electric method concentration system (9) is communicated with an inlet of a produced water tank (14) through a second intermediate water tank (10), an electric method pH regulator (12) and a manganese sand filter (13), an outlet of the produced water tank (14) is communicated with an inlet of a cooling tower pool through a produced water pump (16), an outlet of the cooling tower pool is communicated with an inlet of the raw water tank (1), and a high-voltage electrostatic polarization device (17) is arranged in the cooling tower pool;

the concentrated water outlet of the electric method concentration system (9) is communicated with the inlet of the waste water collecting tank (18), and the outlet of the waste water collecting tank (18) is communicated with the inlet of the desulfurization process water tank (20).

2. The thermal power plant circulating water non-pharmacological electric combined treatment process system as claimed in claim 1, wherein an outlet of the first intermediate water tank (5) is communicated with a backwash water inlet of the multi-media filter (4) through a first backwash pump (6), and a backwash water outlet of the multi-media filter (4) is communicated with an inlet of the wastewater collection tank (18).

3. The chemical-free electric combined treatment process system for the circulating water of the thermal power plant as claimed in claim 1, wherein the raw water tank (1) is communicated with the inlet of the low-voltage electric descaling reactor (3) through a first water inlet pump (2), and the cleaning wastewater outlet of the low-voltage electric descaling reactor (3) is communicated with the inlet of the wastewater collection tank (18).

4. The thermal power plant circulating water non-pharmacy electric combined treatment process system as claimed in claim 1, characterized in that the bottom outlet of the first intermediate water tank (5) is communicated with the cooling tower pool through a drainage pump (8).

5. The thermal power plant circulating water non-pharmacy electric-process combined treatment process system as claimed in claim 1, characterized in that the first intermediate water tank (5) is in communication with the electric-process concentration system (9) via a second water inlet pump (7).

6. The thermal power plant circulating water non-pharmacy electric-process combined treatment process system as claimed in claim 1, characterized in that the second intermediate water tank (10) is in communication with the inlet of the electric-process pH adjuster (12) via a third water inlet pump (11).

7. The system for the chemical-free and electric combined treatment process of the circulating water in the thermal power plant as claimed in claim 1, wherein a cleaning wastewater outlet of the electric pH regulator (12) is communicated with an inlet of the wastewater collection tank (18).

8. The thermal power plant circulating water non-pharmacy electric method combined treatment process system as claimed in claim 1, characterized in that the outlet of the water production tank (14) is communicated with the backwash water inlet of the manganese sand filter (13) through a second backwash pump (15), the backwash water outlet of the manganese sand filter (13) is communicated with the inlet of the wastewater collection tank (18), and the outlet of the wastewater collection tank (18) is communicated with the desulfurization process water tank (20) through a wastewater lift pump (19).

9. An agentless electric method combined treatment process method for circulating water of a thermal power plant is characterized in that the agentless electric method combined treatment process system for circulating water of a thermal power plant based on claim 1 comprises the following steps:

1) circulating water of a thermal power plant enters a raw water tank (1) for buffering and homogenizing, then enters a low-voltage electric descaling reactor (3) for electrolysis, alkalinity reduction and descaling treatment, and water output by the low-voltage electric descaling reactor (3) enters a multi-medium filter (4) for filtering to remove suspended matters and reduce turbidity;

2) the water output by the multi-medium filter (4) enters a first intermediate water tank (5), the water output by the first intermediate water tank (5) is divided into two paths, one path enters a tower pool of a cooling tower, and the other path enters an electrical method concentration system (9) for desalination treatment;

3) the produced water output by the electric method concentration system (9) enters a second intermediate water tank (10), then enters an electric method pH regulator (12) to regulate the pH value to be below 7, the water output by the electric method pH regulator (12) enters a manganese sand filter (13) to be filtered, the water output by the manganese sand filter (13) enters a produced water tank (14), the water output by the produced water tank (14) enters a cooling tower pool, and the water in the cooling tower pool enters a raw water tank (1) after being treated by a high-voltage electrostatic polarization device (17).

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