A nuclear-powered floating liquefied natural gas (FLNG) drive system

Abstract

A floating liquefied natural gas (FLNG) drive system based on nuclear power, having a steam generation module. A nuclear reactor is provided in the reactor compartment of the steam generation module. The nuclear reactor is sequentially connected to a steam generator and a main circulation pump to form a first circulation network; the heat of the saturated steam generated by the steam generator is sequentially provided to a power generation system, a natural gas liquefaction system, a pump turbine system, an engine room section heating system, a service steam system, and an upper oil and gas treatment and common system. The present invention overcomes the deficiencies of the prior art, applies the heat energy converted from nuclear energy to each system in the floating device, and each system is stable, reliable, energy-saving, environment-friendly, and reduces pollution. At the same time, the present invention applies the medium-temperature seawater after cooling the exhausted steam to a fresh water production system, which not only meets the fresh water demand of the steam system, but also effectively utilizes the medium-temperature seawater, improves the system thermal efficiency, and reduces environmental damage.

Description

Technical Field

[0001] The present invention relates to the technical field of floating liquefied natural gas (FLNG) devices, and particularly to a driving system for a floating liquefied natural gas (FLNG) device based on nuclear power. Background Art

[0002] A floating natural gas liquefaction device (FLNG) is a new type of floating production storage and offloading device (FPSO) that integrates the liquefaction, storage, and loading and unloading of offshore natural gas. FLNG has currently become a research hotspot in the development fields of deepwater oil and gas fields and large and medium-sized marginal oil and gas fields. The driving system of FLNG is closely related to the power generation system, natural gas treatment system, liquefaction system, and storage system of FLNG, and is the power source of the FLNG plant. Currently, the main driving methods for FLNG in deepwater oil and gas fields and large and medium-sized marginal oil and gas fields are steam turbine driving and gas turbine driving, both of which use the combustion of fossil fuels as the energy source, resulting in a large fuel consumption. Taking an FLNG plant with an annual output of 2 million tons as an example, the annual gas consumption is respectively about 0.19 billion cubic meters and 0.14 billion cubic meters, and the annual gas consumption cost is about 50 million yuan. While consuming a large amount of energy, it also brings huge pollution to the environment. Summary of the Invention

[0003] To solve the above problems, the present invention provides a driving system for a floating liquefied natural gas (FLNG) device based on nuclear power, aiming to achieve the purpose of reasonably using nuclear power as an energy source, avoiding the consumption of a large amount of fossil fuels and damage to the marine environment. The technical solution adopted is as follows:

[0004] A driving system for a floating liquefied natural gas (FLNG) device based on nuclear power includes a steam generation module. A nuclear reactor is arranged in the reactor compartment of the steam generation module. The nuclear reactor is sequentially connected to a steam generator and a main circulation pump to form a first circulation network; the saturated steam generated by the steam generator enters the power generation system, natural gas liquefaction system, pump turbine system, engine room section heating system, miscellaneous steam system, and upper oil and gas treatment and public system respectively.

[0005] The steam generator is respectively connected to the generator turbine of the power generation system and the refrigerant turbine of the natural gas liquefaction system. After the 4mpa - 8mpa saturated steam generated by the steam generator does work in the motor turbine and the refrigerant turbine, the exhausted steam converges into the exhausted steam main pipe. The exhausted steam main pipe is sequentially connected to a condenser, a condensate pump, a warm water tank, a deaerator, a feed water pump, and a high-pressure feed water heater. The high-pressure feed water heater returns to the steam generator, and a feed water control valve is arranged between the high-pressure feed water heater and the steam generator.

[0006] After the steam generator is connected to the pump turbine of the pump turbine system, the engine room section heating system, the service steam system, and the upper oil and gas treatment and public system via a throttling device, it merges into the exhaust steam main pipe. The exhaust steam main pipe is successively connected to a condenser, a condensate pump, a warm water tank, a deaerator, a feed water pump, and a high-pressure feed water heater, and the high-pressure feed water heater returns to the steam generator.

[0007] The other end of the warm water tank is connected to a fresh water tank. A fresh water pump is provided between the fresh water tank and the warm water tank, and a warm water tank control valve is provided between the fresh water pump and the warm water tank.

[0008] Seawater is respectively pumped into the condenser and the vacuum flash type water maker by a seawater pump. After heat exchange in the vacuum flash type water maker, the seawater returns to the sea. The condenser is connected to the vacuum flash type water maker and the fresh water tank in sequence through pipelines. The seawater enters the vacuum flash type water maker through the condenser to form fresh water and enters the fresh water tank.

[0009] The natural gas liquefaction system is equipped with a refrigerant compressor, a refrigerant heat exchanger, an LNG storage tank, and a condensate oil tank. One end of the refrigerant compressor is connected to one end of the refrigerant heat exchanger to form a second circulation network, and the other end of the refrigerant heat exchanger is respectively connected to the LNG storage tank and the gas-liquid separation and treatment system; after being processed by the gas-liquid separation and treatment system, the natural gas enters the refrigerant heat exchanger and the condensate oil tank respectively.

[0010] For the above-mentioned floating liquefied natural gas device (FLNG) drive system based on nuclear power, further, in the first circulation network, pressure stabilizers are provided on the path from the main circulation pump to the nuclear reactor and on the path from the nuclear reactor to the steam generator.

[0011] For the above-mentioned floating liquefied natural gas device (FLNG) drive system based on nuclear power, further, the nuclear reactor is a pressurized water reactor, and the heat-carrying medium is water pressurized to 15 mpa - 20 mpa.

[0012] For the above-mentioned floating liquefied natural gas device (FLNG) drive system based on nuclear power, further, the engine room section heating system includes heating of the dirty oil tank, the lubricating oil tank, the oil residue tank, and the water maker.

[0013] For the above-mentioned floating liquefied natural gas device (FLNG) drive system based on nuclear power, further, the service steam system includes an inert gas deck water seal, a ballast water filter room radiator, a wash deck seawater heater, and winter cabin heating.

[0014] For the above-mentioned floating liquefied natural gas device (FLNG) drive system based on nuclear power, further, the upper oil and gas treatment and public system includes heating of the molecular sieve heater, the amine solution reboiler, the separation tower reboiler, the condensate oil stabilizer tower reboiler, domestic hot water, room heating, and pipeline tracing.

[0015] The above-mentioned floating liquefied natural gas (FLNG) drive system based on nuclear power, further, a first liquid level sensor is arranged in the warm water tank, and the first liquid level sensor is signal-connected to the warm water tank control valve.

[0016] The above-mentioned floating liquefied natural gas (FLNG) drive system based on nuclear power, further, a second liquid level sensor is arranged in the steam generator, and the second liquid level sensor is signal-connected to the feed water control valve.

[0017] The above-mentioned floating liquefied natural gas (FLNG) drive system based on nuclear power, further, the generator turbine is connected to the generator through a pipeline.

[0018] The above-mentioned floating liquefied natural gas (FLNG) drive system based on nuclear power, further, the heat-carrying medium flowing in the first circulation network is water.

[0019] The beneficial effects of the present invention are as follows:

[0020] 1. The present invention uses nuclear energy as the power source of FLNG, applies the heat energy converted from nuclear energy to different heat energy users of high, medium and low levels respectively, and recovers and utilizes the heat energy carried by the exhaust steam, thereby improving the utilization rate of nuclear energy. Steam is used as the heat-carrying medium of the drive system, which has strong heat-carrying capacity, is safe and reliable, and has high heat exchange efficiency.

[0021] 2. Nuclear fuel is a clean energy source, which is green, low-carbon, energy-saving and environmentally friendly, has a high energy density, a long single-reactor fuel life, and strong power. Nuclear fuel is economical and environmentally friendly for high-energy-consuming FLNG plants.

[0022] 3. A large amount of fresh water required by the FLNG nuclear power secondary loop steam system is the warm seawater after heat exchange with the exhaust steam in the condenser. While reducing the heat energy demand of the water maker and improving the water making efficiency, a large amount of warm seawater is utilized due to the heat exchange and temperature rise in the condenser, thereby reducing the direct discharge amount of warm seawater, improving the system thermal efficiency, and reducing the damage to the ecological environment. Brief Description of the Drawings

[0023] Figure 1 It is the system diagram of the present invention;

[0024] Wherein: 1 - nuclear reactor, 2 - steam generator, 3 - main circulation pump, 4 - pressurizer, 5 - throttling device, 6 - pump turbine, 7 - generator turbine, 8 - dirty oil tank, 9 - oil residue tank, 10 - lubricating oil tank, 11 - water maker, 12 - inert gas deck water seal, 13 - radiator in ballast water filter room, 14 - seawater heater for tank washing, 15 - cabin heating, 16 - molecular sieve heater, 17 - amine liquid reboiler, 18 - fractionating tower reboiler, 19 - condensate oil stabilizer reboiler, 20 - domestic hot water, 21 - room heating, 22 - pipeline heat tracing, 23 - gas-liquid separation and treatment system, 24 - refrigerant turbine, 25 - refrigerant compressor, 26 - refrigerant heat exchanger, 27 - LNG storage tank, 28 - condensate oil tank, 29 - vacuum boiling type water maker, 33 - feed water control valve, 34 - temperature water tank control valve, 35 - condenser, 36 - condensate pump, 37 - temperature water tank, 38 - deaerator, 39 - feed water pump, 40 - high-pressure feed water heater, 41 - seawater pump, 42 - fresh water pump, 43 - fresh water tank, 44 - generator. Detailed implementation mode

[0025] The present invention will be further described in conjunction with the accompanying drawings.

[0026] Embodiment 1

[0027] As Figure 1 shown, a floating liquefied natural gas (FLNG) drive system based on nuclear power has a reactor cabin, and a nuclear reactor is arranged in the reactor cabin. The nuclear reactor adopts a conventional pressurized water reactor, and the pressurized water reactor is sequentially connected to a steam generator and a main circulation pump through pipelines. The main circulation pump returns to the pressurized water reactor to form a first circulation network. A pressurizer is arranged between the path where the main circulation pump returns to the pressurized water reactor and the path where the pressurized water reactor leads to the steam generator. The pressurizer is used to prevent equipment damage caused by excessive pressure in the first circulation network and the boiling of the coolant caused by too low pressure.

[0028] The steam generator is respectively connected to the generator turbine of the power generation system and the refrigerant turbine of the natural gas liquefaction system through pipelines, and the generator turbine is connected to the generator. The saturated steam of 4 mpa - 8 mpa generated in the steam generator is supplied to the generator turbine and the refrigerant turbine. After the saturated steam of 4 mpa - 8 mpa does work in the generator turbine, the thermal energy of the steam is converted into mechanical energy. The generator turbine rotor is connected to the generator, and the mechanical energy is converted into electrical energy for use by all ship instruments, life and lighting.

[0029] The natural gas liquefaction system also includes a refrigerant compressor, a refrigerant heat exchanger, an LNG storage tank, and a condensate oil tank. The refrigerant heat exchanger and the connecting compressor form a second circulation network. The other end of the connecting compressor is connected to a refrigerant turbine. Natural gas enters the gas-liquid separation and treatment system. After gas-liquid separation and a series of operations such as acid removal, dehydration, and mercury removal, the separated condensate oil is injected into the condensate oil tank. The purified natural gas separated is heat-exchanged with high-pressure refrigerant in the refrigerant heat exchanger, becomes liquefied natural gas, and is then injected into the LNG tank. The low-pressure refrigerant after heat exchange returns to the refrigerant compressor, is compressed into high-pressure refrigerant, and continues to provide cooling energy for the refrigerant heat exchanger. The saturated steam at 4 mpa - 8 mpa does work in the refrigerant turbine, drives the operation of the refrigerant compressor in the natural gas liquefaction system, converts thermal energy into mechanical energy, and the low-pressure refrigerant is compressed into high-pressure refrigerant in the refrigerant compressor. The exhausted steam formed after the saturated steam does work in the motor turbine and the refrigerant turbine converges into the exhausted steam main pipe. The exhausted steam main pipe is successively connected to a condenser, a condensate water pump, a warm water tank, a deaerator, a feed water pump, and a high-pressure feed water heater. The high-pressure feed water heater returns to the steam generator.

[0030] The steam generator enters the pump group turbine system at 1.6 mpa - 1.96 mpa via a throttling device, drives the pump group turbine, and drives the operation of the seawater pump, condensate water pump, fresh water pump, and feed water pump. The high-temperature saturated steam converges into the exhausted steam main pipe after passing through the pump group turbine. The high-temperature saturated steam passes through the throttling device and enters the engine room section heating system, the miscellaneous steam system, and the upper oil and gas treatment and public system at 0.4 mpa - 0.98 mpa. The engine room section heating system includes the heating of the dirty oil tank, lubricating oil tank, oil residue tank, and water maker. The miscellaneous steam system includes the heating of the dirty inert gas deck water seal, the radiator in the ballast water filter room, the wash water heater for the wash water, and the heating of the winter cabin. The upper oil and gas treatment and public system includes the heating of the molecular sieve heater, amine solution reboiler, separation tower reboiler, condensate oil stabilizer tower reboiler, domestic hot water, room heating, and pipeline tracing. The high-temperature saturated steam converges into the exhausted steam main pipe after doing work in each system.

[0031] The condenser is successively connected to a vacuum boiling water maker, a fresh water tank, a fresh water pump, and a warm water tank. A warm water tank control valve is provided between the fresh water pump and the warm water tank. Seawater in the sea (this is low-temperature seawater) is respectively pumped into the condenser and the vacuum boiling water maker via the seawater pump. In the condenser, the exhausted steam in the exhausted steam main pipe enters the condenser, exchanges heat with the low-temperature seawater and condenses into water, and is then pumped into the warm water tank by the condensate water pump for heating. The low-temperature seawater forms medium-temperature seawater after exchanging heat with the exhausted steam in the condenser. The medium-temperature seawater enters the vacuum boiling water maker; at the same time, the low-temperature seawater in the sea provides low temperature for the condensation of the water maker in the vacuum boiling water maker. The low-temperature seawater forms medium-temperature seawater after exchanging heat in the vacuum boiling water maker and returns to the sea together with the medium-temperature seawater entering the water maker after exchanging heat with the condenser. The internal vacuum degree of the vacuum boiling water maker is 90%. When it is heated to about 45 °C through the steam circuit and boils and evaporates, it is replenished into the fresh water tank after being condensed by the low-temperature seawater.

[0032] A first liquid level sensor is arranged in the warm water tank. The control signal of the first liquid level sensor is connected to the control valve of the warm water tank. When the water level is too low, the control valve of the warm water tank is automatically opened, and fresh water is pumped from the fresh water tank into the warm water tank by the fresh water pump. After being heated at a low temperature in the warm water tank, the circulating heat-carrying medium is deaerated by the deaerator and then pumped into the high-pressure feed water heater by the feed water pump for heating. After being heated by the high-pressure feed water heater, the heat-carrying medium enters the steam generator at a pressure of 7 mpa to 12 mpa. The heat-carrying medium at 7 mpa to 12 mpa enters the steam generator and exchanges heat with the water at 15 - 20 mpa coming out of the pressurized water reactor and evaporates to form saturated steam at 4 mpa - 8 mpa and the cooled heat-carrying medium. The cooled heat-carrying medium is pumped into the pressurized water reactor by the main circulation pump for heating and continues to circulate in the first circulation network. The saturated steam at 4 mpa - 8 mpa is supplied to the power generation system, the natural gas liquefaction system, the pump turbine system, the engine room section heating system, the miscellaneous steam system, and the upper oil and gas treatment and common system.

[0033] A second liquid level sensor is arranged in the steam generator. The second liquid level sensor is signal-connected to the feed water control valve. The second liquid level sensor sends a liquid level signal to the feed water control valve. The feed water control valve replenishes the heat-carrying medium into the steam generator in real time according to the liquid level signal. The heat-carrying medium enters the steam generator and exchanges heat with the water at 15 mpa - 20 mpa coming out of the pressurized water reactor and evaporates to form high-temperature saturated steam at 4 mpa - 8 mpa.

[0034] The present invention overcomes the deficiencies of the prior art, applies the heat energy converted from nuclear energy to the power generation system, the turbine system, the natural gas liquefaction system, the engine room and cargo oil heating system, the miscellaneous steam system, and the process system of the upper module of the floating device. The system is stable, reliable, energy-saving, environment-friendly, and reduces pollution. At the same time, the present invention applies the medium-temperature seawater after cooling the exhausted steam to the fresh water production system, which not only meets the fresh water demand of the steam system but also effectively utilizes the medium-temperature seawater, improves the thermal efficiency of the system, and reduces environmental damage.

Claims

1. A floating liquefied natural gas (FLNG) drive system based on nuclear power, characterized in that: There is a steam generation module. A nuclear reactor is arranged in the reactor compartment of the steam generation module. The nuclear reactor is sequentially connected to a steam generator and a main circulation pump to form a first circulation network; the steam generator generates saturated steam and enters the power generation system, the natural gas liquefaction system, the pump group turbine system, the engine room section heating system, the miscellaneous steam system, and the upper oil and gas treatment and public system respectively; The steam generator is respectively connected to the generator turbine of the power generation system and the refrigerant turbine of the natural gas liquefaction system. After the 4mpa - 8mpa saturated steam generated by the steam generator does work in the motor turbine and the refrigerant turbine, the exhausted steam converges into the exhausted steam main pipe. The exhausted steam main pipe is sequentially connected to a condenser, a condensate pump, a warm water tank, a deaerator, a feed water pump, and a high-pressure feed water heater. The high-pressure feed water heater returns to the steam generator, and a feed water control valve is arranged between the high-pressure feed water heater and the steam generator; After the steam generator is connected to the pump group turbine of the pump group turbine system, the engine room section heating system, the miscellaneous steam system, and the upper oil and gas treatment and public system via a throttling device, it converges into the exhausted steam main pipe. The exhausted steam main pipe is sequentially connected to a condenser, a condensate pump, a warm water tank, a deaerator, a feed water pump, and a high-pressure feed water heater. The high-pressure feed water heater returns to the steam generator; The other end of the warm water tank is connected to a fresh water tank. A fresh water pump is arranged between the fresh water tank and the warm water tank, and a warm water tank control valve is arranged between the fresh water pump and the warm water tank; Seawater is respectively pumped into the condenser and the vacuum flash desalination unit by a seawater pump. After the seawater exchanges heat in the vacuum flash desalination unit, it returns to the sea. The condenser is sequentially connected to the vacuum flash desalination unit and the fresh water tank through pipelines. The seawater enters the vacuum flash desalination unit through the condenser to form fresh water and enters the fresh water tank; The natural gas liquefaction system is equipped with a refrigerant compressor, a refrigerant heat exchanger, an LNG storage tank, and a condensate oil tank. The refrigerant compressor is connected to one end of the refrigerant heat exchanger to form a second circulation network. The other end of the refrigerant heat exchanger is respectively connected to the LNG storage tank and the gas-liquid separation and treatment system; natural gas is processed by the gas-liquid separation and treatment system and then enters the refrigerant heat exchanger and the condensate oil tank respectively.

2. A driving system of a floating liquefied natural gas (FLNG) device based on nuclear power according to claim 1, characterized in that: In the first circulation network, a pressure stabilizer is arranged on the path from the main circulation pump to the nuclear reactor and on the path from the nuclear reactor to the steam generator.

3. A driving system for a floating liquefied natural gas (FLNG) device based on nuclear power according to claim 1, characterized in that: The nuclear reactor is a pressurized water reactor, and the heat carrier medium is water pressurized to 15mpa - 20mpa.

4. A drive system for a floating liquefied natural gas (FLNG) device based on nuclear power according to claim 1, characterized in that: The engine room section heating system includes the heating of the dirty oil tank, the lubricating oil tank, the oil residue tank, and the desalination unit.

5. A drive system for a floating liquefied natural gas (FLNG) device based on nuclear power according to claim 1, characterized in that: The miscellaneous steam system includes the inert gas deck water seal, the radiator in the ballast water filter room, the wash water heater for the ship's hold, and the heating for the cabins in winter.

6. A driving system for a floating liquefied natural gas (FLNG) plant based on nuclear power according to claim 1, characterized in that: The upper oil and gas treatment and public system includes the heating of the molecular sieve heater, the amine solution reboiler, the separation tower reboiler, the condensate oil stabilizer tower reboiler, the domestic hot water, the room heating, and the tracing heating for pipelines.

7. A drive system for a floating liquefied natural gas (FLNG) device based on nuclear power according to claim 1, characterized in that: A first liquid level sensor is arranged in the warm water tank, and the first liquid level sensor is signal-connected to the warm water tank control valve.

8. A drive system for a floating liquefied natural gas (FLNG) plant based on nuclear power according to claim 1, characterized in that: A second liquid level sensor is arranged in the steam generator, and the second liquid level sensor is signal-connected to the feed water control valve.

9. A driving system for a floating liquefied natural gas plant (FLNG) based on nuclear power according to claim 1, characterized in that: The generator turbine is connected to the generator through a pipeline.

10. A driving system for a floating liquefied natural gas (FLNG) plant based on nuclear power according to claim 1, characterized in that: The heat carrier medium flowing in the first circulation network is water.

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