A multi-energy complementary cooling system for LNG power plants with energy storage devices

Abstract

The present invention discloses a multi-energy complementary cooling system for an LNG power plant with an energy storage device, including an LNG storage tank, a high-pressure water bath vaporizer, an LNG cold energy utilization system, an auxiliary heater, a gas turbine, a waste heat boiler flue gas waste heat refrigeration system, a waste heat boiler steam refrigeration system, a water storage system and a cooling pipeline system. The present invention fully utilizes LNG cold energy and waste heat boiler waste heat refrigeration, and uses waste heat boiler steam refrigeration as a cold source supplementary multi-energy complementary cooling system. The system is suitable for a combined cycle power plant using LNG as fuel. By using this system, the LNG cold energy of the power plant can be fully utilized, and the waste heat of the waste heat boiler flue gas can also be used for refrigeration; when the above two methods are insufficient for cooling, waste heat boiler steam refrigeration is also used as a cold source supplement.

Description

Technical Field

[0001] The present invention belongs to the field of waste heat and waste cold utilization in power plants, and relates to a multi-energy complementary cooling system for LNG power plants with an energy storage device. The system utilizes LNG cold energy and waste heat from waste heat boilers for cooling, and adopts waste heat boiler steam cooling as a cold source to supplement the multi-energy complementary cooling. Background Art

[0002] LNG is a low-temperature liquid mixture formed by dehydrating and desulfurizing natural gas and freezing and liquefying it through a low-temperature process. The temperature is -162°C. LNG can not only be used as fuel, but also carries 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 LNG gasification and the sensible heat of heating to ambient temperature). At present, when power stations use LNG as fuel, they usually need to gasify and heat it first. In this process, the cold energy carried by LNG is usually taken away by tap water. By recycling and utilizing LNG cold energy, not only is there no consumption of natural gas fuel itself, but also no additional environmental pollution is generated. At the same time, the recovered LNG cold energy can be used to produce air conditioning cold water to achieve centralized cooling, which also has good economic benefits.

[0003] At present, the exhaust gas temperature of the waste heat boiler of large F-class combined cycle units is generally around 90°C. If the fuel used by the power plant is LNG, the fuel composition does not contain sulfur, and there is no need to consider the acid corrosion of the waste heat boiler. The corresponding exhaust gas dew point temperature of the waste heat boiler is equal to the water dew point temperature of the flue gas. Therefore, in theory, the maximum temperature that the flue gas of the waste heat boiler can be reduced to is about 60°C (considering that the flue gas temperature should be 10°C higher than the dew point temperature). If the waste heat in the exhaust gas can be converted into hot water by increasing the tail heating surface, and the air conditioning cold water is produced by the hot water type lithium bromide chiller to achieve centralized cooling, it not only meets the goal of energy cascade utilization, but also can bring considerable economic benefits to the power plant. In addition to the waste heat cooling of the waste heat boiler, directly using the waste heat boiler steam for cooling is also an effective means to increase the cooling capacity of the power plant and improve economic benefits. Summary of the invention

[0004] Taking into account the growing demand for cooling in cities, starting from the goal of achieving cascade utilization of energy and improving the economic benefits of power plants, the present invention provides a multi-energy complementary cooling system for LNG power plants with an energy storage device in response to the cooling needs of users. The system is equipped with a water cold storage device, which makes full use of LNG cold energy and waste heat cooling from waste heat boilers, and uses waste heat boiler steam cooling as a cold source to supplement the multi-energy complementary cooling.

[0005] The present invention is achieved by adopting the following technical solutions:

[0006] An LNG power plant multi-energy complementary cooling system with an energy storage device comprises an LNG storage tank, a high-pressure water bath gasifier, an LNG cold energy utilization system, an auxiliary heater, a gas turbine, a waste heat boiler flue gas waste heat cooling system, a waste heat boiler steam cooling system, a water cold storage system and a cooling pipeline system (9).

[0007] Among them, an LNG gasification system is arranged next to the LNG storage tank, and the LNG gasification system is connected in parallel with the LNG cold energy utilization system; the outlet of the LNG storage tank is divided into two routes, one is connected to the inlet of the high-pressure water bath type gasifier, the outlet of the high-pressure water bath type gasifier 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;

[0008] The LNG cold energy utilization system is used to recover the cold energy of LNG gasification through a two-stage heat exchange system, and use this part of the cold energy to produce 5°C primary cold water, which is then transported to the cooling pipe system or the water cold storage system. The 12°C primary warm water returned from the cooling pipe system or the water cold storage system is returned to the LNG cold energy utilization system to form a cycle;

[0009] The waste heat boiler flue gas waste heat refrigeration system is used to extract a stream of hot water from the condensate heater at the tail of the waste heat boiler to produce 5°C primary cold water and transport it to the cooling pipe system or the water cold storage system. The 12°C primary warm water returned from the cooling pipe system or the water cold storage system is returned to the waste heat boiler flue gas waste heat refrigeration system to form a cycle;

[0010] The waste heat boiler steam refrigeration system is used to draw a stream of steam from the medium-pressure superheated steam pipeline of the waste heat boiler to produce primary cold water at 5°C and transport it to the cooling pipeline system or the water cold storage system. The primary warm water at 12°C returned from the cooling pipeline system and the water cold storage system is returned to the waste heat boiler steam refrigeration system to form a cycle;

[0011] In the cooling pipe system, the primary cold water at 7°C from the cooling pipe is used to be transported to various cooling users. After being heated up, the secondary warm water at 14°C is returned through the cooling pipe to form a cycle.

[0012] A further improvement of the present invention is that the LNG cold energy utilization system includes a two-stage heat exchange system, wherein the heat exchanger of the first-stage heat exchange system is provided with an LNG inlet and an LNG outlet, the outlet of the refrigerant storage tank of the first-stage heat exchange system is connected to the refrigerant inlet of the heat exchanger of the first-stage heat exchange system, the refrigerant outlet of the heat exchanger of the first-stage heat exchange system is connected to the refrigerant inlet of the heat exchanger of the second-stage heat exchange system through the refrigerant pump of the first-stage heat exchange system, the refrigerant outlet of the heat exchanger of the second-stage heat exchange system is connected to the refrigerant storage tank inlet of the first-stage heat exchange system, and the water storage tank outlet of the second-stage heat exchange system is connected to the refrigerant storage tank inlet of the first-stage heat exchange system. The water inlet of the heat exchanger of the secondary heat exchange system, the water outlet of the heat exchanger of the secondary heat exchange system is connected to the cooling pipe system and the water storage system through the water pump of the secondary heat exchange system; the 12℃ water in the water storage tank of the secondary heat exchange system enters the heat exchanger of the secondary heat exchange system to exchange heat with the refrigerant, and the cold water that can be cooled to 5℃ enters the cooling pipe system and the water storage system through the water pump of the secondary heat exchange system; the 12℃ water returned from the cooling pipe system and the water storage system is transported to the water storage tank of the secondary heat exchange system, and then enters the heat exchanger of the secondary heat exchange system for heat exchange and cooling, forming a refrigeration cycle loop.

[0013] A further improvement of the present invention is that the waste heat refrigeration system of the waste heat boiler flue gas includes a hot water type lithium bromide refrigerator, a water pump of the waste heat refrigeration system and a condensate heater. The condensate heater is arranged at the flue gas outlet of the waste heat boiler, and its outlet is divided into two paths, one path is connected to the hot water type lithium bromide refrigerator, and the other path is connected to a circulation loop composed of a deoxygenation drum and a deoxygenation evaporator; the hot water type lithium bromide refrigerator is used to produce 5°C cold water, which is transported to the cooling pipe system and the water cold storage system through the water pump of the waste heat boiler system, and the primary warm water of 12°C returned from the cooling pipe system and the water cold storage system is transported to the hot water type lithium bromide refrigerator for refrigeration to form a circulation loop.

[0014] A further improvement of the present invention is that, after the water cold storage system completes the cold storage process, the cold energy generated by the waste heat boiler flue gas waste heat refrigeration system will be directly supplied to the cooling pipe system for use by cold users.

[0015] A further improvement of the present invention is that the waste heat boiler steam refrigeration system includes a steam-type lithium bromide refrigerator and a water pump of the steam refrigeration system. The superheated steam drawn out from the outlet of the medium-pressure superheater of the waste heat boiler is sent to the steam-type lithium bromide refrigerator, and returns to the inlet of the condensate heater after heat exchange. The steam-type lithium bromide refrigerator obtains 5°C cold water, which is sent to the water storage system and the cooling pipe system through the water pump of the steam refrigeration system. The 12°C water returned from the water storage system and the cooling pipe system is sent to the steam-type lithium bromide refrigerator for refrigeration, forming a circulation loop.

[0016] A further improvement of the present invention is that the water cold storage system includes a water cold storage tank and a water distributor. When the combined cycle unit is running, the water cold storage system is in a cold storage function. The upper and lower parts of the water cold storage tank are both provided with water distributors. The primary cold water of 5°C flows into the bottom of the water cold storage tank through the lower water distributor, and the primary warm water of 12°C is drawn out from the upper part of the water cold storage tank through the upper water distributor and enters the LNG cold energy utilization system, the waste heat boiler flue gas waste heat refrigeration system or the waste heat boiler steam refrigeration system for cooling.

[0017] When the combined cycle unit is shut down, the water storage system is in the cooling function. The 5°C primary cold water generated by the water storage system flows out of the bottom of the water storage tank through the lower water distributor and enters the cooling pipe system. The return 12°C primary warm water flows into the upper part of the water storage tank through the upper water distributor.

[0018] A further improvement of the present invention is that the cooling pipeline system includes a water pump for secondary water of the cooling pipeline system and a plate heat exchanger of the cooling pipeline system. When the combined cycle unit is running, primary cold water at 5°C enters the cooling pipeline system, and after heat exchange in the plate heat exchanger, the primary warm water with a temperature increase of 12°C is returned to the refrigeration system to form a circulation loop; the secondary cold water at 7°C from the cooling pipeline is transported to each cold user through the water pump for secondary water of the cooling pipeline system, and after the temperature increase, the secondary warm water with a temperature of 14°C is returned to the plate heat exchanger through the cooling pipeline to form a circulation loop;

[0019] When the combined cycle unit is shut down, the 5°C primary cold water from the water storage system enters the cooling pipe system, and after heat exchange in the plate heat exchanger of the cooling pipe system, the primary warm water with a temperature rise of 12°C returns to the water storage system to form a circulation loop; the 7°C secondary cold water from the cooling pipe is transported to each cold user by the secondary water pump of the cooling pipe system, and after heating, the secondary warm water with a temperature of 14°C returns to the plate heat exchanger of the cooling pipe system through the cooling pipe to form a circulation loop.

[0020] The present invention has at least the following beneficial technical effects:

[0021] The present invention provides an LNG power plant multi-energy complementary cooling system with an energy storage device, comprising an LNG storage tank, a high-pressure water bath gasifier, an LNG cold energy utilization system, an auxiliary heater, a gas turbine, a waste heat boiler flue gas waste heat refrigeration system, a waste heat boiler steam refrigeration system, a water storage system and a cooling pipeline system.

[0022] Among them, the LNG gasification system is connected in parallel with the LNG cold energy utilization system. When the LNG cold energy utilization system is not in operation, it will not affect the normal production of the process equipment on the main pipeline. In case of emergency, the LNG flow rate of the LNG cold energy utilization system can be reduced through the automatic control system, and LNG will gasify the gasification system. The LNG gasification system includes a high-pressure water bath gasifier and related piping systems.

[0023] LNG cold energy utilization system: The cold energy of LNG gasification is recovered through a two-stage heat exchange system, and this part of the cold energy is used to produce 5°C primary cold water, which is then transported to the cooling pipe system and the water cold storage system. The 12°C primary warm water returned from the cooling pipe system and the water cold storage system is returned to the LNG cold energy utilization system through a water pump to form a cycle. The system includes a two-stage heat exchange system, and each stage of the heat exchange system includes: a heat exchanger, a refrigerant, a refrigerant storage tank, a refrigerant pump, and related piping systems. When the cooling demand is small or no cooling is required, the LNG cold energy utilization system can be reduced or shut down through the automatic control system.

[0024] Waste heat boiler flue gas waste heat refrigeration system: A stream of hot water is drawn from the condensate heater at the tail of the waste heat boiler and transported to the hot water type lithium bromide chiller through the water supply pipe. After the hot water is cooled in the refrigeration unit to form warm water, it is returned to the condensate pump outlet pipe through the return pipe and the booster pump to form a cycle. At the same time, the hot water type lithium bromide chiller produces 5°C primary cold water and transports it to the cooling pipe system and the water storage system. The 12°C primary warm water returned from the cooling pipe system and the water storage system is returned to the waste heat boiler flue gas waste heat refrigeration system through the water pump to form a cycle. When the cooling demand is small or no cooling is required, the automatic control system can be used to reduce or shut down the amount of hot water drawn from the condensate heater at the tail of the waste heat boiler and reduce or shut down the cooling.

[0025] Waste heat boiler steam refrigeration system: A stream of steam is drawn from the medium-pressure superheated steam pipeline of the waste heat boiler to the steam-type lithium bromide chiller. After the steam is cooled in the refrigeration unit to form warm water, it is returned to the condensate pump outlet pipeline through the return pipe and the booster pump to form a cycle. At the same time, the steam-type lithium bromide chiller produces 5°C primary cold water and transports it to the cooling pipeline system and the water storage system. The 12°C primary warm water returned from the cooling pipeline system and the water storage system is returned to the waste heat boiler steam refrigeration system through the water pump to form a cycle. When the cooling demand is small or no cooling is required, the automatic control system can be used to reduce or shut down the amount of steam drawn from the medium-pressure superheated steam pipeline of the waste heat boiler and reduce or shut down the cooling.

[0026] Water cold storage system: When storing cold, the 5°C primary cold water generated by the LNG cold energy utilization system, the waste heat boiler flue gas waste heat refrigeration system or the waste heat boiler steam refrigeration system (the three are collectively referred to as the refrigeration system) passes through the lower water distributor and slowly flows into the bottom of the water cold storage tank. The 12°C primary warm water is drawn out from the top of the water cold storage tank through the upper water distributor and enters the refrigeration system for cooling. The inclined temperature layer gradually rises from bottom to top in the water cold storage tank until it disappears completely and the tank is full of cold water. The cold storage is completed and the automatic control is carried out. system, close the relevant pipelines, and stop the refrigeration system from supplying cold to the water storage system; when cooling, the primary cold water at 5°C flows out of the bottom of the water storage tank through the lower water distributor and enters the cooling pipe system, and the returning primary warm water at 12°C flows into the upper part of the water storage tank through the upper water distributor. The inclined temperature layer gradually decreases from top to bottom in the water storage tank until it disappears completely. When the water storage tank is filled with warm water, cooling is completed, and the automatic control system is used to close the relevant pipelines to stop the water storage system from supplying cold to the cooling pipe system.

[0027] Cooling pipe system: The primary cold water at 5°C from the refrigeration system or the water storage system enters the cooling pipe system. After heat exchange in the plate heat exchanger, the primary warm water with a temperature rise of 12°C is returned to the LNG cold energy utilization system or the water storage system to form a cycle. The primary cold water at 7°C from the cooling pipe is transported to each cold user, and after heating, it becomes secondary warm water at 14°C and returns to the plate heat exchanger through the cooling pipe to form a cycle.

[0028] In summary, considering the growing demand for cooling in cities, starting from the goal of achieving cascade utilization of energy and improving the economic benefits of power plants, the present invention makes full use of LNG cooling energy and waste heat refrigeration from waste heat boilers, and uses waste heat boiler steam refrigeration as a multi-energy complementary cooling system to supplement the cold source. The system is suitable for combined cycle power plants that use LNG as fuel. By using this system, the LNG cooling energy of the power plant can be fully utilized, and the waste heat of the flue gas from the waste heat boiler can also be used for cooling; when the above two methods are insufficient for cooling, waste heat boiler steam refrigeration is also used as a cold source supplement.

[0029] At present, most combined cycle units have to undertake the task of peak load regulation of the power grid, and two-shift operation has become the norm. Therefore, when the unit is running, a water storage device can be used to store cold energy, so that the cold energy can be continuously utilized when the combined cycle unit is shut down, making the LNG power plant a centralized cooling center in the region. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the overall system of the present invention.

[0031] Figure 2 This is a schematic diagram of the LNG cold energy utilization system.

[0032] Figure 3 This is a schematic diagram of the waste heat refrigeration system of waste heat boiler flue gas.

[0033] Figure 4 Schematic diagram of the waste heat boiler steam refrigeration system.

[0034] Figure 5 Schematic diagram of the water cooling system.

[0035] Figure 6 Schematic diagram of the cooling pipe system.

[0036] Description of reference numerals:

[0037] 1 is an LNG storage tank; 2 is a high-pressure water bath vaporizer; 3 is an LNG cold energy utilization system; 3A is a refrigerant storage tank for the primary heat exchange system; 3B is a heat exchanger for the primary heat exchange system; 3C is a refrigerant pump for the primary heat exchange system; 3D is a heat exchanger for the secondary heat exchange system; 3E is a water pump for the secondary heat exchange system; 3F is a water storage tank for the secondary heat exchange system; 4 is an auxiliary heat device; 5 is a gas turbine; 6 is a waste heat boiler flue gas waste heat refrigeration system; 6A is a hot water type lithium bromide refrigerator; 6B is a water pump for the waste heat refrigeration system; 6C is a condensate heater; 7 is a waste heat boiler steam refrigeration system; 7A is a steam type lithium bromide refrigerator; 7B is a water pump for the steam refrigeration system; 8 is a water cold storage system; 8A is a water cold storage tank; 8B is a water distributor; 9 is a cooling pipe system; 9A is a water pump for secondary water in the cooling pipe system; 9B is a plate heat exchanger for the cooling pipe system. DETAILED DESCRIPTION

[0038] The present invention will be described in detail below with reference to the accompanying drawings:

[0039] like Figure 1 As shown, the present invention provides an LNG power plant multi-energy complementary cooling system with an energy storage device, comprising:

[0040] The LNG gasification system is arranged beside the LNG storage tank 1. The LNG gasification system is connected in parallel with the LNG cold energy utilization system 3. When the LNG cold energy is utilized, part of the LNG enters the LNG cold energy utilization system 3, and the remaining LNG enters the high-pressure water bath vaporizer 2 for gasification and then enters the gas turbine 5 as fuel.

[0041] LNG cold energy utilization system 3. Figure 2As shown, the LNG cold energy utilization system 3 includes a two-stage heat exchange system. Under normal operating conditions, the refrigerant in the refrigerant storage tank 3A of the primary heat exchange system enters the heat exchanger 3B of the primary heat exchange system to exchange heat with LNG and cool it down, and then passes through the refrigerant pump 3C of the primary heat exchange system and is then sent to the heat exchanger 3D of the secondary heat exchange system; the LNG after heat exchange and temperature increase enters the auxiliary heat device 4 to be heated, and then enters the gas turbine 5 as fuel; the 12°C water in the water storage tank 3F of the secondary heat exchange system enters the heat exchanger 3D of the secondary heat exchange system to exchange heat with the refrigerant, and after cooling to 5°C cold water, enters the water storage system 8 and the cooling pipe system 9 through the water pump 3E of the secondary heat exchange system. The 12°C water returned from the water storage system 8 and the cooling pipe system 9 is transported to the water storage tank 3F of the secondary heat exchange system, and then enters the heat exchanger 3D of the secondary heat exchange system to exchange heat and cool down, forming a refrigeration cycle. When the water cold storage system 8 completes the cold storage process, the cold energy generated by the LNG cold energy utilization system 3 will be directly supplied to the cold supply pipeline system 9 for use by cold users.

[0042] Waste heat boiler flue gas waste heat refrigeration system 6. Figure 3 As shown, under normal operation, the hot water drawn out from the outlet of the condensate heater 6C at the flue gas outlet of the waste heat boiler is divided into two paths, one is sent to the hot water type lithium bromide refrigerator 6A, and returns to the inlet of the condensate heater 6C after heat exchange, and the other is connected to the circulation loop composed of the deoxygenation drum and the deoxygenation evaporator. The hot water type lithium bromide refrigerator 6A produces 5°C cold water, which is sent to the water storage system 8 and the cooling pipeline system 9 through the water pump 6B of the waste heat refrigeration system. The 12°C water returned from the water storage system 8 and the cooling pipeline system 9 is transported to the hot water type lithium bromide refrigerator 6A for refrigeration to form a circulation loop. When the water storage system 8 completes the cold storage process, the cold energy generated by the waste heat boiler flue gas waste heat refrigeration system 6 will be directly supplied to the cooling pipeline system 9 for use by cold users.

[0043] Waste heat boiler steam refrigeration system 7. When the LNG cold energy utilization system 3 and the waste heat boiler flue gas waste heat refrigeration system 6 cannot meet the cooling demand, the waste heat boiler steam refrigeration system 7 will be put into use as a cold source supplement. Figure 4 As shown, under normal operation, the superheated steam drawn out from the outlet of the medium-pressure superheater of the waste heat boiler is sent to the steam-type lithium bromide refrigerator 7A, and returns to the inlet of the condensate heater after heat exchange. The steam-type lithium bromide refrigerator 7A produces 5°C cold water, which is sent to the water storage system 8 and the cooling pipe system 9 through the water pump 7B of the steam refrigeration system. The 12°C water returned from the water storage system 8 and the cooling pipe system 9 is transported to the steam-type lithium bromide refrigerator 7A for refrigeration, forming a cycle. When the water storage system 8 completes the cold storage process, the cold energy generated by the waste heat boiler steam refrigeration system 7 will be directly supplied to the cooling pipe system 9 for use by cold users.

[0044] Water storage system8. Figure 5 As shown, when the combined cycle unit is running, the cold storage function of the water cold storage system 8 will be enabled, that is, the 5°C primary cold water generated by the LNG cold energy utilization system 3, the waste heat boiler flue gas waste heat refrigeration system 6 or the waste heat boiler steam refrigeration system 7 (the three are collectively referred to as the refrigeration system) passes through the lower water distributor 8B and slowly flows into the bottom of the water cold storage tank 8A, and the 12°C primary warm water is drawn from the top of the water cold storage tank 8A through the upper water distributor 8B and enters the refrigeration system for cooling. The inclined temperature layer gradually rises from bottom to top in the water cold storage tank 8A until it is completely cooled. The temperature gradient disappears completely and the tank is filled with cold water, completing the cold storage process. When the combined cycle unit is shut down, the cooling function of the cold water storage system 8 is enabled, i.e., the primary cold water of 5°C generated by the cold water storage system 8 flows out of the bottom of the cold water storage tank 8A through the lower water distributor 8B and enters the cooling pipe system 9. The returning primary warm water of 12°C flows into the upper part of the cold water storage tank 8A through the upper water distributor 8B. The inclined temperature layer gradually decreases from top to bottom in the cold water storage tank 8A until it disappears completely and the cold water storage tank 8A is filled with warm water, completing the cooling process.

[0045] Cooling pipe system 9. Figure 6 When the combined cycle unit is in operation, the primary cold water at 5°C from the LNG cold energy utilization system 3, the waste heat boiler flue gas waste heat refrigeration system 6 or the waste heat boiler steam refrigeration system 7 (the three are collectively referred to as the refrigeration system) enters the cooling pipe system 9, and after heat exchange in the plate heat exchanger 9B of the cooling pipe system, the primary warm water with a temperature increase of 12°C returns to the refrigeration system to form a circulation loop; the secondary cold water at 7°C from the cooling pipe is transported to each cold user through the secondary water pump 9A of the cooling pipe system, and after heating, the secondary warm water with a temperature of 14°C returns to the plate heat exchanger 9B of the cooling pipe system through the cooling pipe system to form a circulation loop. When the combined cycle unit is shut down, the primary cold water at 5°C from the water storage system 8 enters the cooling pipe system 9, and after heat exchange in the plate heat exchanger 9B of the cooling pipe system, the primary warm water with a temperature rise of 12°C returns to the water storage system 8, forming a circulation loop; the secondary cold water at 7°C from the cooling pipe is transported to each cold user through the secondary water pump 9A of the cooling pipe system, and after heating, the secondary warm water with a temperature of 14°C returns to the plate heat exchanger 9B of the cooling pipe system through the cooling pipe, forming a circulation loop.

[0046] When the cooling capacity of the LNG cold energy utilization system 3 exceeds the cooling demand, only the LNG cold energy utilization system 3 is used for cooling; when the cooling capacity of the LNG cold energy utilization system 3 cannot meet the cooling demand, the waste heat boiler flue gas waste heat refrigeration system 6 is used as a supplementary cold source to meet the cooling demand; when the cooling capacity of both the LNG cold energy utilization system 3 and the waste heat boiler flue gas waste heat refrigeration system 6 cannot meet the cooling demand, the waste heat boiler steam refrigeration 7 is used as a supplementary cold source to meet the cooling demand.

Claims

1. A multi-energy complementary cooling system for an LNG power plant with an energy storage device, characterized in that: It includes an LNG storage tank (1), a high-pressure water bath vaporizer (2), an LNG cold energy utilization system (3), an auxiliary heater (4), a gas turbine (5), a waste heat boiler flue gas waste heat refrigeration system (6), a waste heat boiler steam refrigeration system (7), a water cold storage system (8) and a cooling pipeline system (9); wherein: An LNG gasification system is arranged next to the LNG storage tank (1), and the LNG gasification system is connected to the LNG cold energy utilization system (3) in parallel; the outlet of the LNG storage tank (1) is divided into two paths, one path is connected to the inlet of the high-pressure water bath type gasifier (2), the outlet of the high-pressure water bath type gasifier (2) is connected to the gas turbine (5), and the other path is connected 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 connected to the gas turbine (5) through the auxiliary heater (4); The LNG cold energy utilization system (3) is used to recover cold energy from LNG gasification through a two-stage heat exchange system, and use this part of the cold energy to produce primary cold water at 5°C, and transport it to the cooling pipe system (9) and the water cooling storage system (8); the primary warm water at 12°C returned from the cooling pipe system (9) and the water cooling storage system (8) is returned to the LNG cold energy utilization system (3), forming a cycle; The waste heat boiler flue gas waste heat refrigeration system (6) is used to extract a stream of hot water from the condensate heater at the tail of the waste heat boiler to produce primary cold water at 5°C and transport it to the cooling pipe system (9) and the water cold storage system (8); the primary warm water at 12°C returned from the cooling pipe system (9) and the water cold storage system (8) is returned to the waste heat boiler flue gas waste heat refrigeration system (6) to form a cycle; The waste heat boiler steam refrigeration system (7) is used to draw a stream of steam from the medium-pressure superheated steam pipeline of the waste heat boiler to produce primary cold water at 5°C and transport it to the cooling pipeline system (9) and the water cold storage system (8); the primary warm water at 12°C returned from the cooling pipeline system and the water cold storage system is returned to the waste heat boiler steam refrigeration system (7) to form a cycle; In the cooling pipe system (9), the primary cold water at 7°C from the cooling pipe is used to be delivered to various cooling users, and after being heated up to form secondary warm water at 14°C, it is returned through the cooling pipe to form a cycle; The LNG cold energy utilization system (3) includes a two-stage heat exchange system, wherein the heat exchanger (3B) of the first-stage heat exchange system is provided with an LNG inlet and an LNG outlet, the outlet of the refrigerant storage tank (3A) of the first-stage heat exchange system is connected to the refrigerant inlet of the heat exchanger (3B) of the first-stage heat exchange system, the refrigerant outlet of the heat exchanger (3B) of the first-stage heat exchange system is connected to the refrigerant inlet of the heat exchanger (3D) of the second-stage heat exchange system through the refrigerant pump (3C) of the first-stage heat exchange system, the refrigerant outlet of the heat exchanger (3D) of the second-stage heat exchange system is connected to the inlet of the refrigerant storage tank (3A) of the first-stage heat exchange system, and the outlet of the water storage tank (3F) of the second-stage heat exchange system is connected to the water inlet of the heat exchanger (3D) of the second-stage heat exchange system. The water outlet of the heat exchanger (3D) of the secondary heat exchange system is connected to the cooling pipe system (9) and the water storage system (8) through the water pump (3E) of the secondary heat exchange system; the 12°C water in the water storage tank (3F) of the secondary heat exchange system enters the heat exchanger (3D) of the secondary heat exchange system to exchange heat with the refrigerant, and the cold water can be cooled to 5°C, and enters the cooling pipe system (9) and the water storage system (8) through the water pump (3E) of the secondary heat exchange system; the 12°C water returned from the cooling pipe system (9) and the water storage system (8) is transported to the water storage tank (3F) of the secondary heat exchange system, and then enters the heat exchanger (3D) of the secondary heat exchange system to exchange heat and cool down, thereby forming a refrigeration cycle; The water cooling system (8) comprises a water cooling tank (8A) and a water distributor (8B). When the combined cycle unit is in operation, the water cooling system (8) is in a cooling function. The upper and lower parts of the water cooling tank (8A) are both provided with water distributors (8B). Primary cold water at 5°C flows into the bottom of the water cooling tank (8A) through the lower water distributor (8B). Primary warm water at 12°C is drawn out from the upper part of the water cooling tank (8A) through the upper water distributor (8B) and enters the LNG cold energy utilization system (3), the waste heat boiler flue gas waste heat refrigeration system (6) or the waste heat boiler steam refrigeration system (7) for cooling. When the combined cycle unit is shut down, the water storage system (8) is in a cooling function, and the primary cold water at 5°C generated by the water storage system (8) flows out of the bottom of the water storage tank (8A) through the lower water distributor (8B) and enters the cooling pipe system (9), and the returning primary warm water at 12°C flows into the upper part of the water storage tank (8A) through the upper water distributor (8B); The cooling pipe system (9) includes a water pump (9A) for secondary water of the cooling pipe system and a plate heat exchanger (9B) for the cooling pipe system. When the combined cycle unit is in operation, primary cold water at 5°C enters the cooling pipe system (9), and after heat exchange in the plate heat exchanger (9B), the primary warm water with a temperature of 12°C is returned to the refrigeration system, thereby forming a circulation loop; secondary cold water at 7°C from the cooling pipe is transported to various cold users through the water pump (9A) for secondary water of the cooling pipe system, and after being heated to form secondary warm water with a temperature of 14°C, it is returned to the plate heat exchanger (9B) through the cooling pipe, thereby forming a circulation loop; When the combined cycle unit is shut down, the primary cold water at 5°C from the water storage system (8) enters the cooling pipe system (9), and after heat exchange in the plate heat exchanger (9B) of the cooling pipe system, the primary warm water with a temperature rise of 12°C returns to the water storage system (8), thereby forming a circulation loop; the secondary cold water at 7°C from the cooling pipe is transported to each cooling user through the secondary water pump (9A) of the cooling pipe system, and after being heated to form secondary warm water at 14°C, returns to the plate heat exchanger (9B) of the cooling pipe system via the cooling pipe system, thereby forming a circulation loop.

2. The multi-energy complementary cooling system of an LNG power plant with an energy storage device according to claim 1 is characterized in that: The waste heat boiler flue gas waste heat refrigeration system (6) comprises a hot water type lithium bromide refrigerator (6A), a water pump (6B) of the waste heat refrigeration system and a condensate heater (6C). The condensate heater (6C) is arranged at the waste heat boiler flue gas outlet, and its outlet is divided into two paths, one path is connected to the hot water type lithium bromide refrigerator (6A), and the other path is connected to a circulation loop composed of a deaeration drum and a deaeration evaporator; the hot water type lithium bromide refrigerator (6A) is used to produce cold water at 5°C, which is transported to a cooling pipe system (9) and a water cold storage system (8) through a water pump (6B) of the waste heat refrigeration system, and the primary warm water at 12°C returned from the cooling pipe system (9) and the water cold storage system (8) is transported to the hot water type lithium bromide refrigerator (6A) for refrigeration, thereby forming a circulation loop.

3. The multi-energy complementary cooling system of an LNG power plant with an energy storage device according to claim 1 is characterized in that: When the water cold storage system (8) completes the cold storage process, the cold energy generated by the waste heat boiler flue gas waste heat refrigeration system (6) will be directly supplied to the cooling pipe system (9) for use by cold users.

4. The multi-energy complementary cooling system for LNG power plants with energy storage devices according to claim 1 is characterized in that: The waste heat boiler steam refrigeration system (7) comprises a steam-type lithium bromide refrigerator (7A) and a water pump (7B) of the steam refrigeration system. The superheated steam drawn out from the outlet of the medium-pressure superheater of the waste heat boiler is sent to the steam-type lithium bromide refrigerator (7A) and returned to the inlet of the condensate heater after heat exchange. The steam-type lithium bromide refrigerator (7A) produces cold water at 5°C, which is sent to the water storage system (8) and the cooling pipe system (9) through the water pump (7B) of the steam refrigeration system. The water at 12°C returned from the water storage system (8) and the cooling pipe system (9) is sent to the steam-type lithium bromide refrigerator (7A) for refrigeration, thereby forming a circulation loop.

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