LNG (Liquefied Natural Gas) marine carbon capture system utilizing cold energy of LNG

Abstract

The invention discloses an LNG (liquefied natural gas) ship carbon capture system utilizing cold energy of LNG. The LNG ship carbon capture system comprises a carbon capture module and a liquid cargo processing module, the carbon capture module comprises a CO2 capture mechanism, a CO2 separation mechanism and a CO2 liquefaction storage mechanism which are connected in sequence; the CO2 capture mechanism comprises a first heat exchange device and an absorption tower, the CO2 separation mechanism comprises a second heat exchange device and a separation tower, the CO2 liquefaction storage mechanism comprises a gaseous CO2 storage tank, a compressor, a dryer, a third heat exchange device and a liquid CO2 storage tank which are connected in sequence, and the liquid cargo processing module comprises a plurality of liquid cargo tanks and a gasification processing module; the gasification treatment module comprises a forced gasifier and a gas heater, cold energy to be released of liquefied natural gas is perfectly combined with cold energy needed by the carbon capture system, and recycling of cold energy of an LNG ship and energy consumption reduction of the marine carbon capture system can be achieved. The forced gasification amount can be adjusted according to the flue gas temperature and the flue gas amount, and stable operation of the system is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of marine LNG, and particularly relates to an LNG marine carbon capture system that utilizes the cold energy of liquefied natural gas. Background Art

[0002] The marine carbon capture system reduces the carbon dioxide emissions of ships, separates and captures CO2 (carbon dioxide) in the exhaust gas of ships, and then liquefies and stores it to prevent it from directly entering the atmosphere and exacerbating the greenhouse effect. At present, the relatively mature marine carbon capture solution in technical research is the organic amine solution absorption method. The organic amine solution absorption method treats the carbon-containing flue gas after combustion, which is mainly divided into three steps: (1) CO2 capture - pre-cooling the flue gas and lean liquid (organic amine solution without CO2), and absorbing and capturing CO2; (2) CO2 separation - heating the rich liquid (organic amine solution with high CO2 content) to desorb and separate CO2; (3) CO2 liquefaction storage - cooling, compressing, liquefying and storing the desorbed gaseous CO2.

[0003] The operation of the related equipment of the above marine carbon capture solution requires high costs. Specifically analyzed for each of the above steps, the treatment process requires a large amount of energy consumption. CO2 capture requires a large amount of cold energy to cool the high-temperature flue gas and lean liquid, CO2 separation requires a large amount of heat energy to heat the rich liquid, and CO2 liquefaction storage requires a large amount of cold energy to cool the gaseous CO2. Therefore, it is crucial to research and develop a carbon capture system with low energy consumption. Summary of the Invention

[0004] The purpose of the present invention is to provide an LNG marine carbon capture system that utilizes the cold energy of liquefied natural gas in view of the deficiencies of the prior art.

[0005] The technical solution for the present invention to solve the above problems is: an LNG marine carbon capture system that utilizes the cold energy of liquefied natural gas, including a carbon capture module and a liquid cargo processing module;

[0006] The carbon capture module includes a CO 2 capture mechanism, a CO 2 separation mechanism, and a CO 2 liquefaction storage mechanism;

[0007] The CO 2 capture mechanism includes a first heat exchange device and an absorption tower. The first heat exchange device includes a first intake pipe and a first exhaust pipe. The absorption tower includes a second intake pipe, a second exhaust pipe, a first liquid inlet pipe, and a first liquid discharge pipe. The first exhaust pipe is connected to the second intake pipe;

[0008] The CO 2The separation mechanism includes a second heat exchange device and a separation tower. A second liquid inlet pipe is provided above the side wall of the separation tower, a second liquid discharge pipe is provided at the bottom of the separation tower, and a third exhaust pipe is provided at the top of the separation tower. The second heat exchange device includes a third liquid inlet pipe and a third liquid discharge pipe; the first liquid discharge pipe is connected to the second liquid inlet pipe, the second liquid discharge pipe is connected to the third liquid inlet pipe, and the third liquid discharge pipe is connected to the first liquid inlet pipe through a pipeline;

[0009] The CO 2 The liquefied storage mechanism includes a gaseous CO 2 storage tank, a compressor, a dryer, a third heat exchange device, and a liquid CO 2 storage tank connected in sequence. The other end of the gaseous CO 2 storage tank is connected to the third exhaust pipe;

[0010] The liquid cargo processing module includes a plurality of liquid cargo holds and a gasification processing module; the gasification processing module includes a forced gasifier and a gas heater. One end of the forced gasifier is connected to the liquid cargo hold through a liquid cargo pump, and the other end is connected to the gas heater;

[0011] The gas heater is internally provided with a heating coil. The first heat exchange device, the second heat exchange device, and the third heat exchange device are respectively internally provided with a first cooling coil, a second cooling coil, and a third cooling coil. The first cooling coil, the second cooling coil, and the third cooling coil are connected in series through pipelines in sequence. The inlet end of the third cooling coil is connected to the outlet of the heating coil, and the outlet end of the first cooling coil is connected to the inlet of the heating coil.

[0012] Further, the CO 2 The separation mechanism further includes a heat exchanger. The heat exchanger is internally provided with a first heat exchange pipeline and a second heat exchange pipeline. One end of the first heat exchange pipeline is connected to the first liquid discharge pipe, and the other end is connected to the second liquid inlet pipe; one end of the second heat exchange pipeline is connected to the third liquid inlet pipe, and the other end is connected to the second liquid discharge pipe.

[0013] Further, the liquid cargo processing module further includes a volatilization processing module. The volatilization processing module includes a volatilization pipeline and a gas compressor module. The tops of multiple liquid cargo holds are connected to the gas compressor module through the volatilization pipeline.

[0014] Further, it further includes a controller. A temperature sensor and a flow sensor are provided on the first intake pipeline. The temperature sensor, the flow sensor, and multiple liquid cargo pumps are respectively connected to the controller.

[0015] The present invention has beneficial effects:

[0016] The present invention provides an LNG ship carbon capture system that utilizes the cold energy of liquefied natural gas, perfectly combines the cold energy to be released from the liquefied natural gas with the required cold energy of the carbon capture system, can realize the recovery and utilization of the cold energy of the LNG ship and reduce the energy consumption of the ship carbon capture system. By setting a controller and sensors, the forced gasification amount can be adjusted according to the flue gas temperature and the flue gas volume to ensure the stable operation of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic structural diagram of the carbon capture module;

[0018] Figure 2 It is a schematic structural diagram of the liquid cargo processing module;

[0019] In the figure: 1 - first heat exchanger, 2 - absorption tower, 3 - first intake pipe, 4 - first exhaust pipe, 5 - second intake pipe, 6 - second exhaust pipe, 7 - first inlet liquid pipe, 8 - first drain liquid pipe, 9 - second heat exchanger, 10 - heat exchanger, 11 - separation tower, 12 - second inlet liquid pipe, 13 - second drain liquid pipe, 14 - third exhaust pipe, 15 - third inlet liquid pipe, 16 - third drain liquid pipe, 17 - gaseous CO 2 storage tank, 18 - compressor, 19 - dryer, 20 - third heat exchanger, 21 - liquid CO 2 storage tank, 22 - liquid cargo hold, 23 - volatilization pipeline, 24 - gas compressor module, 25 - forced gasifier, 26 - gas heater. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood through specific situations.

[0021] As shown in the figure, an LNG ship carbon capture system that utilizes the cold energy of liquefied natural gas includes a carbon capture module and a liquid cargo processing module;

[0022] The carbon capture module includes a CO 2 capture mechanism, a CO 2 separation mechanism, and a CO 2 liquefied storage mechanism.

[0023] The CO 2The capture mechanism includes a first heat exchange device 1 and an absorption tower 2. The first heat exchange device 1 includes a first inlet pipe 3 and a first exhaust pipe 4. The absorption tower 2 includes a second inlet pipe 5, a second exhaust pipe 6, a first liquid inlet pipe 7 and a first liquid discharge pipe 8. The first exhaust pipe 4 and the second inlet pipe 5 are connected. The carbon-containing flue gas generated by the combustion of the ship engine enters the first heat exchange device 1 from the first inlet pipe 3, is cooled and then enters the absorption tower 2. After passing through the absorption tower 2, gaseous CO 2 is separated from the carbon-containing flue gas, and the decarbonized flue gas is discharged from the second exhaust pipe 6 for subsequent treatment. The CO 2 absorbent liquid is discharged from the first liquid discharge pipe 8 below the absorption tower 2.

[0024] The CO 2 The separation mechanism includes a second heat exchange device 9, a heat exchanger 10 and a separation tower 11. The heat exchanger 10 is provided with a first heat exchange pipe and a second heat exchange pipe. A second liquid inlet pipe 12 is provided above the side wall of the separation tower 11. A second liquid discharge pipe 13 is provided at the bottom of the separation tower 11. A third exhaust pipe 14 is provided at the top of the separation tower 11. The second heat exchange device 9 includes a third liquid inlet pipe 15 and a third liquid discharge pipe 16. One end of the first heat exchange pipe is connected to the first liquid discharge pipe 8, and the other end is connected to the second liquid inlet pipe 12; one end of the second heat exchange pipe is connected to the third liquid inlet pipe 15, and the other end is connected to the second liquid discharge pipe 13. The third liquid discharge pipe 16 is connected to the first liquid inlet pipe 7 through a pipeline. The CO 2 absorbent liquid is discharged from the first liquid discharge pipe 8 below the absorption tower 2, then enters the separation tower 11 through the heat exchanger 10, and the separation tower 11 separates gaseous CO 2 from the CO 2 absorbent liquid. Gaseous CO 2 is discharged from the third exhaust pipe 14. The CO-free 2 absorbent liquid is discharged from the second liquid discharge pipe 13, then passes through the heat exchanger 10 and the second heat exchange device 9 and enters the absorption tower 2 from the first liquid inlet pipe 7. The CO-free 2 absorbent liquid and the CO 2 absorbent liquid exchange heat in the heat exchanger 10. The CO-free 2 absorbent liquid is cooled for the first time. The CO-free 2 absorbent liquid is cooled for the second time in the second heat exchange device 9. 2 The temperature of the absorbent liquid is 100 °C when it is discharged from the second liquid discharge pipe 13 and drops to 35 °C when it enters the absorption tower 2.

[0025] The CO 2 The liquefied storage mechanism includes a gaseous CO2 storage tank 17, a compressor 18, a dryer 19, a third heat exchange device 20 and a liquid CO2 storage tank 21 connected in sequence. The other end of the gaseous CO2 storage tank 17 is connected to the third exhaust pipe 14. The gaseous CO2 to be liquefied needs to be cooled to -44 °C in the third heat exchange device 20.

[0026] The liquid cargo processing module includes a plurality of liquid cargo tanks 22, a gasification processing module, and a volatilization processing module. The volatilization processing module includes a volatilization pipeline 23 and a gas compressor module 24. The tops of the plurality of liquid cargo tanks 22 are connected to the gas compressor module 24 through the volatilization pipeline 23, and the other end of the gas compressor module 24 is connected to a gas user. The gasification processing module includes a forced gasifier 25 and a gas heater 26. One end of the forced gasifier 25 is connected to the liquid cargo tank through a liquid cargo pump, and the other end is connected to the gas heater 26. The other end of the gas heater 26 is connected to a gas user. After passing through the forced gasifier 25, the liquefied natural gas becomes low-temperature natural gas. Although it has been converted from a liquid state to a gaseous state, its temperature is still too low to be directly used by the gas user and needs to pass through the gas heater 26 to release cold energy and increase the temperature before it can be sent to the user. The gas heater 26 is internally provided with a heating coil. The first heat exchange device 1, the second heat exchange device 9, and the third heat exchange device 20 are respectively internally provided with a first cooling coil, a second cooling coil, and a third cooling coil. The first cooling coil, the second cooling coil, and the third cooling coil are connected in series through pipelines in sequence. The inlet end of the third cooling coil is connected to the outlet of the heating coil, and the outlet end of the first cooling coil is connected to the inlet of the heating coil. The heating coil, the first cooling coil, the second cooling coil, and the third cooling coil are internally filled with an intermediate medium. The cold energy absorbed by the intermediate medium from the low-temperature natural gas is sequentially transferred to the third heat exchange device 20, the second heat exchange device 9, and the first heat exchange device 1 to complete the cooling of the three hot ends. After being heated by the three hot ends in turn, the intermediate medium returns to the gas heater 26 to absorb cold energy.

[0027] Based on the actual recorded data of the LNG ship, under normal ship operation conditions, the total gas consumption required by gas users such as the main engine and the generator is about 4000 kg / h. Under the condition of loading and sailing in the cargo hold, the natural gas volatilization amount in the cargo hold is about 2000 Kg / h. Then, the natural gas that needs to release cold energy through the forced gasifier 25 is about 2000 kg / h.

[0028] In one of the embodiments, a controller is further included. A temperature sensor and a flow sensor are provided on the first intake pipe 3. The temperature sensor, the flow sensor, and the plurality of liquid cargo pumps are respectively connected to the controller, and the forced gasification amount can be adjusted according to the flue gas temperature and the flue gas volume to ensure the stable operation of the system.

[0029] The above is only a preferred embodiment of the present invention and is not a limitation to the present invention in other forms. Any person skilled in the art may use the disclosed technical content to make changes or modifications into equivalent embodiments with equivalent changes and apply them to other fields. However, as long as it does not depart from the technical solution content of the present invention, any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. An LNG ship carbon capture system utilizing liquefied natural gas cold energy, characterized in that: It includes a carbon capture module and a liquid cargo handling module; The carbon capture module includes a CO2 capture mechanism, a CO2 separation mechanism and a CO2 liquefaction storage mechanism connected in sequence; The CO2 capture mechanism comprises a first heat exchange device (1) and an absorption tower (2); the first heat exchange device (1) comprises a first air inlet pipe (3) and a first exhaust pipe (4); the absorption tower (2) comprises a second air inlet pipe (5), a second exhaust pipe (6), a first liquid inlet pipe (7) and a first liquid exhaust pipe (8); the first exhaust pipe (4) and the second air inlet pipe (5) are connected; The CO2 separation mechanism comprises a second heat exchange device (9) and a separation tower (11); a second liquid inlet pipe (12) is provided above the side wall of the separation tower (11); a second liquid discharge pipe (13) is provided at the bottom of the separation tower (11); a third exhaust pipe (14) is provided at the top of the separation tower (11); the second heat exchange device (9) comprises a third liquid inlet pipe (15) and a third liquid discharge pipe (16); the first liquid discharge pipe (8) is connected to the second liquid inlet pipe (12); the second liquid discharge pipe (13) is connected to the third liquid inlet pipe (15); and the third liquid discharge pipe (16) is connected to the first liquid inlet pipe (7) through a pipeline; The CO2 liquefied storage mechanism comprises a gaseous CO2 storage tank (17), a compressor (18), a dryer (19), a third heat exchange device (20) and a liquid CO2 storage tank (21) which are connected in sequence, and the other end of the gaseous CO2 storage tank (17) is connected to a third exhaust pipe (14); The liquid cargo processing module comprises a plurality of liquid cargo tanks (22) and a gasification processing module; the gasification processing module comprises a forced gasifier (25) and a gas heater (26); one end of the forced gasifier (25) is connected to the liquid cargo tank via a liquid cargo pump, and the other end is connected to the gas heater (26); A heating coil is provided inside the gas heater (26); a first cooling coil, a second cooling coil and a third cooling coil are provided inside the first heat exchange device (1), the second heat exchange device (9) and the third heat exchange device (20) respectively; the first cooling coil, the second cooling coil and the third cooling coil are connected in series in sequence through a pipeline; the inlet end of the third cooling coil is connected to the outlet end of the heating coil, and the outlet end of the first cooling coil is connected to the inlet end of the heating coil.

2. The LNG ship carbon capture system using liquefied natural gas cold energy as claimed in claim 1, characterized in that: The CO2 separation mechanism also includes a heat exchanger (10), wherein a first heat exchange pipe and a second heat exchange pipe are provided in the heat exchanger (10), wherein one end of the first heat exchange pipe is connected to a first liquid discharge pipe (8), and the other end is connected to a second liquid inlet pipe (12); one end of the second heat exchange pipe is connected to a third liquid inlet pipe (15), and the other end is connected to a second liquid discharge pipe (13).

3. The LNG ship carbon capture system using liquefied natural gas cold energy as claimed in claim 1, characterized in that: The liquid cargo processing module also includes a volatilization processing module, which includes a volatilization pipeline (23) and a fuel gas compressor module (24). The tops of the plurality of liquid cargo tanks (22) are connected to the fuel gas compressor module (24) via the volatilization pipeline (23).

4. The LNG ship carbon capture system using liquefied natural gas cold energy according to any one of claims 1 to 3, characterized in that: It also includes a controller, wherein the first air inlet pipe (3) is provided with a temperature sensor and a flow sensor, and the temperature sensor, the flow sensor and a plurality of liquid cargo pumps are respectively connected to the controller.

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