CN210197801U - A system of LNG cold energy used for spray cooling of air cooling tower - Google Patents

Abstract

The utility model discloses a system for using LNG cold energy for spray cooling of an air cooling tower, comprising an LNG gasification system, an LNG cold energy utilization system and an air cooling tower spray cooling system; the LNG gasification system is arranged beside the LNG storage tank, and is connected with the LNG The cold energy utilization system is connected in parallel, including high-pressure water-bath vaporizers. When LNG cold energy is utilized, part of the LNG enters the high-pressure water-bath vaporizer for gasification and then enters the gas turbine as fuel; LNG cold energy utilization system The cold energy of LNG vaporization is recovered through the two-stage heat exchange system, and this part of the cold energy is used to reduce the water temperature of the external water, and the cooled cold water enters the spray water storage tank of the spray cooling system of the air cooling tower; the spray cooling system of the air cooling tower By sending the spray water in the spray water storage tank into the optimally arranged nozzles, and through spray cooling, the spray can be completely evaporated and the air cooling radiator in the air cooling tower will not be corroded. The utility model is suitable for a combined cycle power plant using LNG as a fuel and an air cooling tower as a cooling system.

Description

A system of LNG cold energy used for spray cooling of air cooling tower

technical field

The utility model belongs to the field of power station cooling systems, in particular to a system for using LNG cold energy for spray cooling of an air cooling tower.

Background technique

my country is a country with severe water shortage. As industrialization, urbanization, and population continue to grow, the problem of water scarcity becomes more acute. In the wet cooling tower, the cooling water mainly transfers the waste heat directly to the air by means of evaporative heat dissipation, which will cause a large amount of water consumption. In the air cooling tower, the air and the cooling water exchange heat through the air cooling radiator, and the cooling water transfers the waste heat to the air by convection heat exchange, avoiding the water consumption caused by the direct contact heat exchange between the cooling water and the air. Therefore, considering the water consumption constraints, air cooling towers can be a very competitive option.

However, a big problem faced by the air cooling tower is that the heat exchange efficiency is not as good as that of the wet cooling tower because the air and the cooling water exchange heat by convection instead of evaporative heat dissipation. Especially in the case of high temperature in summer, with the increase of the ambient air dry bulb temperature, the heat exchange performance of the air-cooling tower will decrease significantly, the condenser pressure of the unit using the air-cooling tower will increase significantly, and the output of the unit will drop significantly. High temperature is also the peak period of residential electricity consumption. Therefore, it is of great practical significance to improve the heat exchange performance of the air cooling tower under high temperature in summer for improving the economic benefits of the unit.

Utility model content

The purpose of the utility model is to solve the problem that the heat exchange efficiency of the air-cooling tower is low in the case of high temperature in summer, and proposes a system for using LNG cold energy for spray cooling of the air-cooling tower.

The utility model adopts the following technical solutions to realize:

A system for using LNG cold energy for spray cooling of an air cooling tower, comprising an LNG gasification system, an LNG cold energy utilization system and an air cooling tower spray cooling system; wherein,

The LNG gasification system is arranged next to the LNG storage tank, and is connected in parallel with the LNG cold energy utilization system, including a high-pressure water-bath vaporizer. The inlet, the outlet of the high-pressure water-bath vaporizer is connected to the gas turbine, and the other is connected to the LNG inlet of the LNG cold energy utilization system, and the LNG outlet of the LNG cold energy utilization system is connected to the gas turbine through the auxiliary heater;

When the LNG cold energy is utilized, the high-pressure water-bath gasifier is used to gasify part of the LNG and then enters the gas turbine as fuel;

The LNG cold energy utilization system is used to recover the remaining part of the cold energy of LNG vaporization through the two-stage heat exchange system, and use this part of the cold energy to reduce the water temperature of the external water, and the cooled cold water enters the spray of the air cooling tower spray cooling system. in water storage tanks;

The air cooling tower spray cooling system is used to send the spray water in the spray water storage tank into the optimally arranged nozzles, and through spray cooling, that is, to ensure that the spray is completely evaporated and does not corrode the air cooling radiator in the air cooling tower.

The further improvement of the utility model is that the two-stage heat exchange system of the LNG cold energy utilization system includes a heat exchanger, a refrigerant, a refrigerant storage tank and a refrigerant pump;

The heat exchanger of the primary heat exchange system is provided with an LNG inlet and an LNG outlet. The outlet of the refrigerant storage tank of the primary heat exchange system is connected to the refrigerant inlet of the heat exchanger of the secondary heat exchange system through the refrigerant pump. The secondary heat exchange system The refrigerant outlet of the heat exchanger is connected to the refrigerant inlet of the heat exchanger of the primary heat exchange system, and the refrigerant outlet of the heat exchanger of the primary heat exchange system is connected to the inlet of the refrigerant storage tank of the primary heat exchange system to form a heat exchange circulation loop;

The external water storage tank outlet of the secondary heat exchange system is connected to the heat exchanger water inlet of the secondary heat exchange system, and the heat exchanger water outlet of the secondary heat exchange system is connected to the spray cooling system through the water pump of the secondary heat exchange system. Spray water tank.

A further improvement of the utility model is that the spray cooling system of the air cooling tower further comprises a water pump and a communication pipe inside the spray cooling system, and the outlet of the spray water storage tank is connected to the nozzle through the water pump and the communication pipe inside the spray cooling system.

A further improvement of the utility model is that the nozzles are arranged at the lower end of the annular plate and away from the air cooling tower.

A further improvement of the utility model lies in that the annular plate is arranged horizontally and closely adheres to the outer wall of the air cooling tower.

A further improvement of the present invention lies in that some nozzles are arranged in a horizontal co-current flow, some are arranged in a counter-current flow, and some are arranged at an angle of 30°. The utility model has the following beneficial technical effects:

LNG is a low-temperature liquid mixture formed by dehydration and desulfurization of natural gas and freezing and liquefaction by a low-temperature process. The temperature is -162 °C. LNG can not only be used as fuel, but also carry a large amount of high-grade cold energy. The cold energy in the LNG gasification process reaches about 830kJ/kg (including the latent heat of gasification of LNG and the sensible heat raised to ambient temperature). At present, when a power station uses LNG as a fuel, it usually needs to be gasified and heated up first. During this process, the cold energy carried by the LNG is usually carried away by the incoming water. Recycling LNG cold energy not only does not consume natural gas fuel itself, but also does not produce additional environmental pollution, which has good economic and social benefits.

The utility model provides a system for using LNG cold energy for spray cooling of an air cooling tower, including an LNG gasification system, an LNG cold energy utilization system and an air cooling tower spray cooling system; wherein, the LNG gasification system and the LNG cold energy utilization system adopt Connected in parallel, when the LNG cold energy utilization system is not running, it will not affect the normal production of the process equipment on the main pipeline; in case of emergency, the LNG flow of the LNG cold energy utilization system is reduced through the automatic control system, and the LNG gasification system gasify. The LNG cold energy utilization system recovers the cold energy of LNG vaporization through the two-stage heat exchange system, and uses this part of the cold energy to reduce the water temperature of the external water, and the cooled cold water enters the spray water storage tank of the spray cooling system of the air cooling tower. The air cooling tower spray cooling system sends the spray water in the spray water storage tank into the optimally arranged nozzles. Through spray cooling, the spray can be completely evaporated without corroding the air-cooling radiator, and the temperature of the incoming air of the air-cooling tower can be greatly reduced, thereby improving the heat exchange efficiency of the air-cooling tower under high temperature conditions in summer.

To sum up, compared with the spray cooling system of the air-cooling tower that does not utilize LNG cold energy, the utility model can use the LNG cold energy utilization system to recover the cold energy in the LNG gasification process under the high temperature in summer, and use it to reduce the air cooling The spray water temperature of the tower spray cooling system can significantly improve the heat exchange effect between the spray water and the air, further reduce the dry bulb temperature of the air entering the air cooling tower, and significantly improve the heat exchange performance of the tower.

Description of drawings

FIG. 1 is a schematic diagram of the overall system of the present invention.

Figure 2 is a schematic diagram of the LNG cold energy utilization system.

Figure 3 is a schematic diagram of the spray cooling system of the air cooling tower.

FIG. 4 is a schematic diagram of the nozzle arrangement of the spray cooling system of the air cooling tower.

Description of reference numbers:

1 is the LNG storage tank; 2 is the high-pressure water bath vaporizer; 3 is the LNG cold energy utilization system; 3A is the heat exchanger of the primary heat exchange system; 3B is the refrigerant storage tank of the primary heat exchange system; 3D is the heat exchanger of the secondary heat exchange system; 3E is the water pump of the secondary heat exchange system; 3F is the external water storage tank of the secondary heat exchange system; 4 is the auxiliary heat exchanger; 5 7 is a gas turbine; 7 is an air cooling tower spray cooling system; 7A is a connecting water pipe inside the spray cooling system; 7B is a ring plate; 7C is a nozzle; 7D is a water pump; 7E is a spray water storage tank; 8 is an air-cooled radiator; 9 is The outer wall of the air cooling tower.

Detailed ways

Below in conjunction with accompanying drawing and example, the utility model will be introduced in detail:

As shown in Figure 1, the utility model provides a kind of LNG cold energy for air cooling tower spray cooling system, including:

The LNG gasification system arranged beside the LNG storage tank 1. The LNG gasification system and the LNG cold energy utilization system 3 are connected in parallel. When the LNG cold energy is utilized, part of the LNG enters the high-pressure water-bath gasifier 2 for gasification, and then enters the gas turbine 5 as fuel.

As shown in FIG. 2 , the LNG cold energy utilization system 3 includes a two-stage heat exchange system. Under normal operation conditions, the refrigerant in the refrigerant storage tank 3B of the primary heat exchange system enters the heat exchanger 3A of the primary heat exchange system through the refrigerant pump 3C of the primary heat exchange system to exchange heat with LNG, cool down, and then send it to the heat exchanger 3A of the primary heat exchange system. into the heat exchanger 3D of the secondary heat exchange system. The heat-exchanged and heated LNG enters the auxiliary heater 4 for heating, and then enters the gas turbine 5 as fuel. The water in the external water storage tank 3F of the secondary heat exchange system enters the heat exchanger 3D of the secondary heat exchange system through the water pump 3E of the secondary heat exchange system to exchange heat with the refrigerant, and then enters the spray water storage tank of the spray cooling system after cooling. In 7E; the refrigerant after heat exchange and temperature rise enters the primary heat exchange system again for heat exchange cycle.

As shown in FIG. 3 , it is an air cooling tower spray cooling system 7 . The spray water from the spray water storage tank 7E enters the nozzle 7C through the water pump 7D and the communication water pipe 7A inside the spray cooling system. The nozzle 7C is arranged at the lower end of the annular plate 7B, and is as far away from the air cooling tower as possible to increase the running distance of the water droplets, enhance the cooling effect, and ensure that the water droplets evaporate completely without corroding the air cooling radiator 8 . The annular plate 7B is arranged horizontally, and is in close contact with the outer wall 9 of the air cooling tower. As shown in FIG. 4 , some nozzles 7C are arranged in a horizontal downstream flow, some are arranged in a countercurrent flow, and some are arranged at an angle of 30°. After the spray water is sprayed from the nozzle 7C, a spray is formed, and it is completely evaporated under the annular plate 7B. The air cooling radiator 8 is not corroded, and a better cooling effect is achieved.

Compared with the air-cooled tower spray cooling system that does not utilize LNG cold energy, the system can use the LNG cold energy utilization system 3 to recover the cold energy in the LNG gasification process under high temperature conditions in summer, and use it to reduce the air-cooled tower spray cooling system 7 The spray water temperature can significantly improve the heat exchange effect between the spray water and the air, further reduce the dry bulb temperature of the air entering the air cooling tower, and significantly improve the heat exchange performance of the tower.

Claims (6)

1. The system for applying LNG cold energy to spray cooling of the air cooling tower is characterized by comprising an LNG gasification system, an LNG cold energy utilization system (3) and an air cooling tower spray cooling system (7); wherein,

the LNG gasification system is arranged beside the LNG storage tank (1) and connected with the LNG cold energy utilization system (3) in a parallel connection mode and comprises a high-pressure water bath type gasifier (2), the outlet of the LNG storage tank (1) is divided into two paths, one path of the LNG storage tank is communicated to the inlet of the high-pressure water bath type gasifier (2), the outlet of the high-pressure water bath type gasifier (2) is communicated to a gas turbine (5), the other path of the LNG storage tank is communicated to the LNG inlet of the LNG cold energy utilization system (3), and the LNG outlet of the LNG cold energy utilization system (3) is communicated to the gas turbine (5) through an auxiliary heater (4);

when LNG cold energy is utilized, the high-pressure water bath type gasifier (2) is used for gasifying part of LNG and then enters a gas turbine (5) as fuel;

the LNG cold energy utilization system (3) is used for recovering cold energy of the gasification of the rest LNG through the two-stage heat exchange system, the cold energy is used for reducing the water temperature of outside water, and cooled cold water enters a spray water storage tank (7E) of the air cooling tower spray cooling system (7);

and the air cooling tower spray cooling system (7) is used for sending spray water in the spray water storage tank (7E) into a nozzle (7C) which is optimally arranged, and ensuring that spray is completely evaporated without corroding an air cooling radiator (8) in the air cooling tower through spray cooling.

2. The system for using LNG cold energy for spray cooling of the air cooling tower as claimed in claim 1, wherein the two-stage heat exchange systems of the LNG cold energy utilization system (3) each comprise a heat exchanger, a refrigerant storage tank and a refrigerant pump;

an LNG inlet and an LNG outlet are arranged on a heat exchanger (3A) of the primary heat exchange system, an outlet of a refrigerant storage tank (3B) of the primary heat exchange system is communicated to a refrigerant inlet of a heat exchanger (3D) of the secondary heat exchange system through a refrigerant pump (3C), a refrigerant outlet of the heat exchanger (3D) of the secondary heat exchange system is communicated to a refrigerant inlet of the heat exchanger (3A) of the primary heat exchange system, and a refrigerant outlet of the heat exchanger (3A) of the primary heat exchange system is communicated to an inlet of the refrigerant storage tank (3B) of the primary heat exchange system to form a heat exchange circulation loop;

an outlet of an external water storage tank (3F) of the secondary heat exchange system is communicated to a water inlet of a heat exchanger (3D) of the secondary heat exchange system, and a water outlet of the heat exchanger (3D) of the secondary heat exchange system is communicated to a spray water storage tank (7E) of the spray cooling system through a water pump (3E) of the secondary heat exchange system.

3. The system for cooling the air cooling tower by spraying with LNG as described in claim 1, wherein the air cooling tower cooling system (7) further comprises a water pump (7D) and a communication water pipe (7A) inside the cooling system, and the outlet of the spray water storage tank (7E) is communicated to the nozzle (7C) through the water pump (7D) and the communication water pipe (7A) inside the cooling system.

4. A system for LNG cold energy for air cooling tower spray cooling according to claim 1 or 3, characterized in that the nozzles (7C) are arranged at the lower end of the annular plate (7B) and away from the air cooling tower.

5. System for LNG cold energy to be used for air cooling tower spray cooling according to claim 4, characterized in that the ring plate (7B) is arranged horizontally and is attached to the air cooling tower outer wall (9).

6. A system for LNG cold energy for air cooling tower spray cooling according to claim 1 or 3, characterized by partial nozzles (7C) in horizontal co-current arrangement, partial counter-current arrangement and partial 30 ° angle inclination arrangement.

Images