Process water circulation cooling system for power plant desulfurization wastewater treatment

Abstract

The utility model discloses a process water circulating cooling system for treating desulfurization wastewater of a power plant. The process water circulating cooling system mainly comprises a cooling water pump unit and a condensing unit, the cooling water pump unit is composed of two cooling water pump branches which are connected in parallel, and each cooling water pump branch mainly comprises a cooling water pump; the condensation unit is composed of a head end condensate water trunk and a tail end condensate water trunk which are connected in parallel. Each condensate water trunk mainly comprises a condenser, a condensate water tank and a condensate pump which are connected in sequence. The input end of the condenser is connected with the output end of the cooling water pump unit; and the condensed water tank is connected with a condensed gas-liquid separator. As desulfurization process water is adopted, compared with a conventional circulating cooling water system, the circulating cooling water system disclosed by the utility model overcomes the defects of large occupied area, complex system and difficulty in management, and realizes simplification and flexibility of equipment. In addition, a desulfurization wastewater treatment cooling system and a desulfurization process water system are combined for use, so that occupied land and investment are saved, energy consumption is reduced, energy can be saved to the maximum extent, and energy conservation and emission reduction in the industrial production field are facilitated.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the related technical field of energy comprehensive utilization especially relates to a process water circulation cooling system for desulfurization wastewater treatment of power plant. BACKGROUND

[0002] At present, the desulfurization wastewater of thermal power plant is concentrated and reduced by low-temperature multi-effect flash evaporation, and then sent to the drying system to realize the goal of zero discharge of wastewater. The main process is that the desulfurization wastewater is directly introduced into the low-temperature vacuum multi-effect evaporator through the buffer tank and the lifting pump, concentrated, and then the concentrated desulfurization wastewater is transported to the drying system through the pump and the pipeline, atomized into the high-temperature bypass flue evaporator, heated and evaporated by using the high-temperature flue gas, and the evaporated flue gas, steam and all particulate matters enter the post-flue of the air preheater to realize the zero discharge of the desulfurization wastewater. In order to ensure the flash evaporation effect, special cooling water needs to be provided to cool the steam. The water consumption is large, and exclusive cooling towers, cooling water pumps and cooling tower fans need to be configured. These devices have the problems of large occupied building area, complex system pipeline setting, increased post-maintenance difficulty, large power consumption and being not conducive to energy saving and emission reduction in the field of industrial production. On the other hand, the desulfurization treatment and wastewater zero discharge system of the power plant is to reduce the impact on the environment during production. Therefore, how to use appropriate methods to improve the utilization rate of water in the plant area, reduce the energy consumption of the auxiliary system of industrial production and provide qualified and stable cooling water to ensure production has become a problem to be solved. SUMMARY

[0003] The utility model wants to solve the technical problem to provide a structure compact, the investment is less, the energy consumption is lower for desulfurization wastewater treatment of process water circulation cooling system of power plant.

[0004] In order to solve the above technical problem, the utility model adopts the following technical scheme:

[0005] The process water circulation cooling system for desulfurization wastewater treatment of power plant is mainly composed of a cooling water pump unit and a condensing unit. The cooling water pump unit is composed of two parallel cooling water pump branches, and each cooling water pump branch mainly includes a cooling water pump. The condensing unit is composed of a first-end condensing water main line and a tail-end condensing water main line in parallel, and each condensing water main line mainly includes a condenser, a condensing water tank and a condensing water pump connected in sequence. The input end of the condenser is connected to the output end of the cooling water pump unit. A condensing gas-liquid separator is arranged on the condensing water tank.

[0006] The input end of the cooling water pump unit is connected to a desulfurization process water tank; the input end of the condenser of the front-end condensing water dry line is connected to a single-effect evaporator, and the output end is connected back to the desulfurization process water tank; the input end of the condenser of the tail-end condensing water dry line is connected to a triple-effect evaporator, and the output end is connected back to the desulfurization process water tank; the input end of the condensing water tank is connected to an input condensing gas-liquid separator and a condenser condensing water, and the condensing water pump is connected to the desulfurization process water tank; the input end of the condensing water tank of the tail-end condensing water dry line is also connected to the triple-effect evaporator; and the condensing water tank is connected to the desulfurization process water tank.

[0007] The cooling water pump branch is composed of a butterfly valve, an expansion joint, a cooling water pump, an expansion joint, a check valve and a butterfly valve connected in sequence; and the output end of the cooling water pump branch is also provided with a pressure gauge and a thermometer.

[0008] The condensing water tank is also provided with a pressure gauge, a thermometer and a liquid level gauge.

[0009] The condensing water tank is connected to two condensing water pump branches, and each condensing water pump branch is composed of a butterfly valve, a condensing water pump, an expansion joint, a check valve and a butterfly valve connected in sequence.

[0010] The pipeline, through which the condensing water pump is connected to the desulfurization process water tank, is provided with an electric butterfly valve, a pressure gauge and a flow meter.

[0011] The condensing gas-liquid separator is connected to two vacuum pumps, and a pressure gauge is arranged between the vacuum pump and the condensing gas-liquid separator.

[0012] In view of the problems of a large occupied area, a complex system, a large power consumption and a large fresh water consumption of a conventional circulating water system of a desulfurization wastewater treatment system of a power plant, the inventor designs a process water circulating cooling system for the desulfurization wastewater treatment of the power plant, which mainly comprises a cooling water pump unit and a condensing unit; the cooling water pump unit is composed of two parallel cooling water pump branches, and each cooling water pump branch mainly comprises a cooling water pump; the condensing unit is composed of a front-end condensing water dry line and a tail-end condensing water dry line in parallel, and each condensing water dry line mainly comprises a condenser, a condensing water tank and a condensing water pump connected in sequence; the input end of the condenser is connected to the output end of the cooling water pump unit; and the condensing water tank is connected to a condensing gas-liquid separator. The system fully utilizes the process water of the desulfurization wastewater system and realizes the maximum energy saving in combination with the characteristics of a large water consumption (more than 200 m 3 / h) and a low temperature requirement of the desulfurization system.

[0013] Compared with the prior art, the process water circulating cooling system for the desulfurization wastewater treatment of the power plant has the following beneficial effects:

[0014] (1) Since the desulfurization process water is used, compared with the conventional circulating cooling water system, the system overcomes the defects of a large occupied area, a complex system and difficult management, and realizes the simplification and flexibility of the equipment.

[0015] (2) The desulfurization system process water is first used in the condenser of the wastewater flash evaporation system, raising the temperature by 5-6° (~32-34°) before being returned to the process water tank. This achieves a combined use of the wastewater zero-discharge cooling system and the desulfurization process water system, saving land and investment, reducing energy consumption, and maximizing energy conservation. At the same time, it also reduces the difficulty of later maintenance and power consumption, which is beneficial to energy conservation and emission reduction in industrial production. Attached Figure Description

[0016] Figure 1 This is a schematic diagram illustrating the structure and principle of the process water circulation cooling system for desulfurization wastewater systems in power plants, as described in this utility model.

[0017] In the diagram: 1. Initial vacuum pump A, 2. Initial vacuum pump B, 3. Initial condenser, 4. Initial condensate gas-liquid separator, 5. Initial condensate tank, 6. Initial condensate pump A, 7. Initial condensate pump B, 8. Tail-end vacuum pump A, 9. Tail-end vacuum pump B, 10. Tail-end condenser, 11. Tail-end condensate gas-liquid separator, 12. Tail-end condensate tank, 13. Tail-end condensate pump A, 14. Tail-end condensate pump B, 15. Cooling water pump A, 16. Cooling water pump B, 17. Expansion joint, 18. Initial condensate tank drained, 19. Tail-end condensate tank drained, 20. Pipeline drained, 21. Pressure gauge, 22. Thermometer, 23. Level gauge, 24. Flow meter, 25-30. Check valve, 31-32. Electric butterfly valve, 33-54. Butterfly valve, 55-56. Pneumatic valve, 57-61. Normally open shut-off valve, 62-73. Ball valve. Detailed Implementation

[0018] I. Basic Structure

[0019] like Figure 1 As shown, the process water circulation cooling system of this utility model for desulfurization wastewater systems in power plants mainly consists of a cooling water pump unit and a condensation unit. Among them,

[0020] The cooling water pump unit consists of two parallel cooling water pump branches. Each cooling water pump branch consists of a butterfly valve, an expansion joint, a cooling water pump, an expansion joint, a check valve, and a butterfly valve connected in sequence. The output end of the cooling water pump branch is also equipped with a pressure gauge and a thermometer.

[0021] The condensing unit is composed of a front-end condensing water main line and a tail-end condensing water main line in parallel, each of which mainly comprises a condenser, a condensing water tank and a condensing water pump connected in sequence; the input end of the condenser is connected to the output end of the cooling water pump unit; a condensing gas-liquid separator is arranged on the condensing water tank; the condensing water tank is connected to two condensing water pump branches; each condensing water pump branch is composed of a butterfly valve, a condensing water pump, an expansion joint, a check valve and a butterfly valve connected in sequence; a pressure gauge, a thermometer and a liquid level gauge are arranged on the condensing water tank; an electric butterfly valve, a pressure gauge and a flow meter are arranged on the pipeline connecting the condensing water pump to the desulfurization process water tank; and the condensing gas-liquid separator is connected to two vacuum pumps, and a pressure gauge is arranged between the vacuum pump and the condensing gas-liquid separator.

[0022] II. Working principle

[0023] The system is connected to desulfurization process water and steam from auxiliary machines of a thermal power plant, and the return water is desulfurization process water and steam condensing water, and the output desulfurization process water is returned to the desulfurization process water tank for recycling. Specifically, the input end of the cooling water pump unit is connected to the desulfurization process water tank; the input end of the condenser of the front-end condensing water main line is connected to a single-effect evaporator, and the output end is connected to the desulfurization process water tank; the input end of the condenser of the tail-end condensing water main line is connected to a triple-effect evaporator, and the output end is connected to the desulfurization process water tank; the input end of the condensing water tank is connected to the input condensing gas-liquid separator and the condenser condensing water, and the condensing water pump is connected to the desulfurization process water tank; the input end of the condensing water tank of the tail-end condensing water main line is also connected to the triple-effect evaporator; and the condensing water tank is also connected to the desulfurization process water tank.

[0024] wherein,

[0025] The main function of the front-end condensing water main line is to condense and supplement water for the auxiliary heat source and the heat source device of the flue gas heat exchanger, transport water, and extract low-temperature steam pipeline vacuum. When the system is started, the desulfurization process water enters the front-end condensing water tank 5 and the condensing water tank 12 through the pneumatic valves 55 and 56, respectively, to supplement water and ensure the vacuum degree of the system. When the front-end condensing water main line is running, the desulfurization process water is transported to a high position through the opening of the butterfly valves 51 and 52, sprayed onto the condensing coil and the filler, and subjected to heat exchange with the steam after the single-effect evaporator from top to bottom in the front-end condenser, and the desulfurization process water is directly recovered to the desulfurization process water tank. The steam after the single-effect evaporator is cooled to form water condensing water; the condensing water is transported to various water points, such as the front-end condenser and other water pump seal flushing water, through the condensing water tank and the cooling water pumps 6A and 7B.

[0026] The waste heat steam from the first evaporator passes through the first end vacuum pump A1, the first end vacuum pump B2, the first end condenser 3 and other related components to become condensed water entering the first end condensed water tank 5; the condensed water passes through the first end condensed water pump A6, the first end condensed water pump B7 to each water point and then returns to the desulfurization process water tank. The main function of the tail end condensed water dry road is to cool the heat source used after the three-effect flash evaporation concentration, to collect the water generated after the system evaporation, to flush each device in the system and to make the flash evaporation concentration produce a certain degree of vacuum. When the tail end condensed water dry road is running, the steam at the outlet of the three-effect separator enters the tail end condenser, is cooled by using cooling water and then enters the tail end condensed water tank. The condensed water in the tail end condensed water tank is delivered to the cooling water main pipe by the tail end condensing pump, enters the desulfurization process water tank and is used as flushing water in the system.

[0027] When the tail end condensed water dry road is running, the desulfurization process water passes through the cooling water pump A15 and the cooling water pump B16 by opening the butterfly valves 51 and 52 to be delivered to a high position and sprayed onto the condensing coil and the filler. The desulfurization process water passes through the tail end condenser from top to bottom and exchanges heat with the steam passing through the three-effect separator and then returns to the desulfurization process water tank. The steam from the outlet of the three-effect separator passes through the tail end vacuum pump A8, the tail end vacuum pump B9, the tail end condenser and the tail end condensed water tank and other related components to become condensed water. The condensed water returns to the desulfurization process water tank by the tail end condensed water pump A13 and the tail end condensed water pump B14.

Claims

1. A process water recycle cooling system for desulfurization wastewater treatment in a power plant, characterized by The cooling water pump unit is composed of two cooling water pump branches in parallel, and each cooling water pump branch mainly comprises a cooling water pump.

2. The cooling system of claim 1, wherein: The input end of the condenser of the condensing water trunk line is connected to a single-effect evaporator, and the output end thereof is connected back to the desulfurization process water tank.

3. The cooling system of claim 2, wherein: The cooling water pump branch is composed of a butterfly valve, an expansion joint, a cooling water pump, an expansion joint, a check valve and a butterfly valve in sequence.

4. The cooling system of claim 2, wherein: The condensing water tank is also provided with a pressure gauge, a thermometer and a liquid level gauge.

5. The cooling system of claim 2, wherein: The condensing water tank is connected to two condensing water pump branches in sequence, and each condensing water pump branch is composed of a butterfly valve, a condensing water pump, an expansion joint, a check valve and a butterfly valve in sequence.

6. The cooling system of claim 2, wherein: The condensing water pump is connected to the desulfurization process water tank through a pipeline provided with an electric butterfly valve, a pressure gauge and a flowmeter.

7. The cooling system of claim 2, wherein: The condensing gas-liquid separator is connected to two vacuum pumps, and a pressure gauge is arranged between the vacuum pump and the condensing gas-liquid separator.

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