Fuel gas supply and carbon capture system

Abstract

The invention discloses a fuel gas supply and carbon capture system, which covers the whole process flows of fuel gas supply, CO2 capture, CO2 compression, CO2 liquefaction, CO2 storage and the like, and fully utilizes the cold energy of BOG (Boil Off Gas) from an LNG (Liquefied Natural Gas) cabin for cooling the BOG compressed by a BOG compressor, so that an additional intercooler, an aftercooler and a fresh water cooling system are not needed; the heat energy of the compressed BOG and the compressed CO2 is fully utilized to heat the BOG from the LNG cabin, so that the temperature of the BOG entering the BOG compressor meets the air inlet temperature requirement of a normal-temperature compressor, and therefore, the BOG compressor can adopt the normal-temperature compressor; heat energy of waste gas of the dual-fuel engine is fully utilized to heat rich liquid, so that additional heating media and heat sources are not needed; the cold energy of BOG from the LNG cabin is fully utilized and used for liquefying CO2, and therefore extra cooling media and cold sources are not needed.

Description

Technical Field

[0001] The present invention relates to the technical field of shipbuilding, and in particular to a gas supply and carbon capture system. Background Art

[0002] Faced with the severe challenge of global climate change, the international community has been paying more and more attention to carbon emissions. Carbon emissions from the shipping industry account for about 2.89% of the total carbon emissions from human activities in the world, making it one of the most active emission reduction industries. Ship propulsion companies and shipbuilding companies are actively promoting the development of decarbonization technologies such as green fuels and carbon capture. Summary of the invention

[0003] In view of this, the present invention provides a fuel gas supply and carbon capture system.

[0004] A gas supply and carbon capture system, including an LNG tank, a BOG compressor unit, a dual-fuel engine, a CO 2 Capture unit, CO 2 Compressor, heat exchanger, CO 2 Storage compartment,

[0005] The CO 2 The capture unit is used to desorb CO from the exhaust gas of the dual-fuel engine using a chemical absorption method. 2 and transported to CO 2 compressor;

[0006] The CO 2 The compressor is used to desorb the CO 2 The pressurized CO 2 into a first hot side end of a heat exchanger;

[0007] The LNG tank is used to store liquid LNG and the BOG gas formed on the top of the tank is sent to the cold side of the heat exchanger;

[0008] The heat exchanger is used to make the pressurized CO 2 Exchange heat with BOG gas and use the cold energy of BOG gas to liquefy CO 2 , and the resulting liquid CO 2 Stored in CO 2 The BOG gas with a relatively high temperature formed in the storage tank is sent to the BOG compressor unit;

[0009] The BOG compressor unit is used to pressurize the BOG gas with a relatively high temperature and then deliver it to the dual-fuel engine for combustion. The BOG compressor unit adopts a normal temperature compressor.

[0010] Preferably, the CO 2The capture unit includes an absorption tower, a desorption tower, a heat exchanger, a rich liquid pump and a lean liquid pump.

[0011] The gas outlet of the dual-fuel engine is connected to the exhaust gas inlet at the bottom of the absorption tower through a pipeline. The exhaust gas of the dual-fuel engine reacts with the absorbent sprayed from the top of the tower and is absorbed in the absorption tower. The remaining gas after decarbonization is discharged from the top of the absorption tower, and the low-temperature rich liquid formed by the reaction is pumped out from the bottom of the tower by a rich liquid pump and sent to the cold side inlet of the heat exchanger.

[0012] The rich liquid flowing out from the cold side outlet of the heat exchanger flows into the desorption tower from the rich liquid inlet at the top of the desorption tower, and is heated to the set temperature in the desorption tower to desorb CO. 2 The rich liquid is regenerated into high-temperature lean liquid, which is pumped out from the bottom of the tower by the lean liquid pump and sent to the hot side inlet of the heat exchanger, where it exchanges heat with the low-temperature rich liquid to desorb the CO 2 Discharged from the top of the tower, after drying and dehydration, it is transported to CO 2 compressor.

[0013] Preferably, the CO 2 The capture unit further comprises a reheater for reheating the undesorbed rich liquid in the desorber.

[0014] Preferably, the absorbent used in the absorption tower is an organic amine solution.

[0015] Preferably, the BOG compressor unit comprises a first-stage BOG compressor and a second-stage BOG compressor, the air inlet of the first-stage BOG compressor is connected to the cold side outlet of the heat exchanger, the air outlet of the first-stage BOG compressor is connected to the second hot side inlet of the heat exchanger, the second hot side outlet of the heat exchanger is connected to the air inlet of the second-stage BOG compressor, the air outlet of the second-stage BOG compressor is connected to the third hot side inlet of the heat exchanger, and the third hot side outlet of the heat exchanger is connected to the air inlet of the dual-fuel engine.

[0016] Preferably, a first three-way control valve is provided on the pipeline connecting the air outlet of the first-stage BOG compressor and the inlet of the second hot side end of the heat exchanger, and one of the outlets of the first three-way control valve is connected to the air inlet of the second-stage BOG compressor through a pipeline;

[0017] A second three-way control valve is provided on the pipeline connecting the air outlet of the secondary BOG compressor and the third hot side inlet of the heat exchanger, and one outlet of the second three-way control valve is connected to the air inlet of the dual-fuel engine through a pipeline.

[0018] Preferably, the first hot side outlet of the heat exchanger is connected to the CO 2 The pipeline connected to the liquid inlet of the storage tank is also connected with a vent pipe.

[0019] Preferably, the heat exchanger is a gas / gas heat exchanger.

[0020] The beneficial effects of the present invention are:

[0021] The gas supply and carbon capture system of the present invention covers the entire process of gas supply, CO2 capture, CO2 compression, CO2 liquefaction, CO2 storage, etc., and fully utilizes the cold energy of BOG from the LNG tank to cool the BOG compressed by the BOG compressor, so no additional intercooler, aftercooler, and fresh water cooling system are required; the thermal energy of the compressed BOG and the compressed CO2 is fully utilized to heat the BOG from the LNG tank so that the temperature entering the BOG compressor reaches the intake temperature requirement of the normal temperature compressor, so the BOG compressor can use a normal temperature compressor; the thermal energy of the exhaust gas of the dual-fuel engine is fully utilized to heat the rich liquid, so no additional heating medium and heat source are required; the cold energy of the BOG from the LNG tank is fully utilized to liquefy CO2, so no additional cooling medium and cold source are required. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 It is a structural schematic diagram of the present invention.

[0024] The meanings of the numbers in the figure are:

[0025] 1 is a dual-fuel engine, 2 is a CO 2 Capture unit, 3 for CO 2 compressor, 4 is a heat exchanger, 5 is an LNG tank, 6 is a CO 2 storage tank, 7 is a BOG compressor unit, 8 is an absorption tower, 9 is a desorption tower, 10 is a heat exchanger, 11 is a rich liquid pump, 12 is a lean liquid pump, 13 is a first pipeline, 14 is a second pipeline, 15 is a third pipeline, 16 is a fourth pipeline, 17 is a fifth pipeline, 18 is a sixth pipeline, 19 is a seventh pipeline, 20 is a sixteenth pipeline, 21 is a ninth pipeline, 22 is a tenth pipeline, 23 is an eleventh pipeline, 24 is a twelfth pipeline, 25 is a thirteenth pipeline, 26 is a fourteenth pipeline, 27 is a fifteenth pipeline, 28 is a reheater, 29 is a primary BOG compressor, and 30 is a secondary BOG compressor. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is described below by the specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0027] The terms used in this disclosure are for the purpose of describing specific embodiments only and are not intended to limit the disclosure. The singular forms of "a", "said" and "the" used in this disclosure and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0028] It should be understood that although the terms first, second, third, etc. may be used in the present disclosure to describe various information, such information should not be limited to these terms and should not be understood as indicating or implying relative importance. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present disclosure, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information.

[0029] In the description of the present invention, it is necessary to understand that the orientations or positional relationships indicated by terms such as “upper”, “lower”, “left”, “right”, “top” and “bottom” are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0030] In the description of the present invention, unless otherwise specified and limited, it should be noted that the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a mechanical connection or an electrical connection, or it can be the internal connection between two components. It can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to the specific circumstances.

[0031] In order to better understand the technical solution of the present invention, the present invention is described in detail below with reference to the accompanying drawings.

[0032] The present invention provides a gas supply and carbon capture system, including an LNG tank 5, a BOG compressor unit 7, a dual-fuel engine 1, a CO 2 Capture unit 2, CO 2 Compressor 3, heat exchanger 4, CO 2 Storage compartment 6,

[0033] The CO2 The capture unit 2 is used to desorb CO from the exhaust gas of the dual-fuel engine 1 by chemical absorption. 2 and transported to CO 2 compressor;

[0034] The CO 2 Compressor 3 is used to desorb the CO 2 The pressurized CO 2 sent to the first hot side end of the heat exchanger 4;

[0035] The LNG tank 5 is used to store liquid LNG and the BOG gas formed on the top of the tank is sent to the cold side end of the heat exchanger 4;

[0036] The heat exchanger 4 is used to make the pressurized CO 2 Exchange heat with BOG gas and use the cold energy of BOG gas to liquefy CO 2 , and the resulting liquid CO 2 Stored in CO 2 The BOG gas with a relatively high temperature formed in the storage tank 6 is sent to the BOG compressor unit 7;

[0037] The BOG compressor unit 7 is used to pressurize the BOG gas with a relatively high temperature and then deliver it to the dual-fuel engine 1 for combustion. The BOG compressor unit 7 uses a normal temperature compressor.

[0038] Specifically, in this embodiment, the CO 2 The capture unit 2 includes an absorption tower 8 , a desorption tower 9 , a heat exchanger 10 , a rich liquid pump 11 , and a lean liquid pump 12 .

[0039] The gas outlet of the dual-fuel engine 1 is connected to the exhaust gas inlet at the lower part of the absorption tower 8 through a pipeline.

[0040] The absorption tower 8 is provided with a waste gas outlet at the top, a rich liquid outlet at the bottom, and a lean liquid inlet at the top. The desorption tower 9 is provided with a rich liquid inlet at the top, a gas outlet at the top, and a lean liquid outlet at the bottom.

[0041] The rich liquid outlet at the bottom of the absorption tower 8 is connected to the inlet of the rich liquid pump 11 through the first pipeline 13, the outlet of the rich liquid pump 11 is connected to the cold side inlet of the heat exchanger 10 through the second pipeline 14, the cold side outlet of the heat exchanger 10 is connected to the rich liquid inlet of the desorption tower 9 through the third pipeline 15, and the gas outlet of the desorption tower 9 is connected to the CO 2The air inlet of the compressor 3 is connected, the lean liquid outlet of the desorption tower 9 is connected to the inlet of the lean liquid pump 12 through the fifth pipeline 17, the outlet of the lean liquid pump 12 is connected to the hot side inlet of the heat exchanger 10 through the sixth pipeline 18, and the hot side outlet of the heat exchanger 10 is connected to the lean liquid inlet of the absorption tower 8 through the seventh pipeline 19.

[0042] The exhaust gas of the dual-fuel engine 1 enters the absorption tower 8 after dust removal. In the absorption tower 8, since the exhaust gas flows from bottom to top, and the absorbent sprayed from the top of the tower flows from top to bottom, the exhaust gas fully contacts with the absorbent in the tower in the reverse direction to react, and the CO in the exhaust gas is 2 The remaining gas after being absorbed by the absorbent and decarbonized is discharged from the top of the absorption tower 8, and the low-temperature rich liquid formed by the reaction is pumped out from the bottom of the tower by the rich liquid pump 11 and sent to the cold side inlet of the heat exchanger 10. After heat exchange with the refluxed high-temperature lean liquid with a higher temperature in the heat exchanger 10, it flows out from the cold side outlet of the heat exchanger 10;

[0043] The rich liquid flowing out from the cold side outlet of the heat exchanger 10 flows into the desorption tower 9 from the rich liquid inlet at the top of the desorption tower 9 to desorb CO 2 The rich liquid is regenerated into a high-temperature lean liquid, which is pumped out from the bottom of the tower by the lean liquid pump 12 and sent to the hot side inlet of the heat exchanger 10. In the heat exchanger 10, heat is exchanged with the low-temperature rich liquid extracted from the absorption tower 8. The heat of the high-temperature lean liquid is used to heat the low-temperature rich liquid extracted from the bottom of the absorption tower 8. After the heat exchange, the temperature of the high-temperature lean liquid is reduced to become a low-temperature lean liquid and is sent back to the upper part of the absorption tower 8 through the seventh pipeline 19 for CO 2 The cyclic absorption and desorption of CO 2 It is discharged from the top of the desorption tower 9 and transported to the CO 2 compressor.

[0044] CO discharged from the top of desorption tower 9 2 CO 2 After compression and pressure increase by the compressor, the gas is sent to the first hot side end of the heat exchanger 4 through the ninth pipeline 21, and the BOG gas formed in the LNG tank 5 is also sent to the cold side end of the heat exchanger 4 through the tenth pipeline 22. Since the temperature of the BOG gas is relatively low, the CO 2 The temperature is higher, so the BOG gas and CO 2 Heat exchange is performed inside the heat exchanger 4, and the cold energy of the BOG gas is used to liquefy CO 2 And liquid CO 2 The eleventh pipeline 23 stores CO 2 The BOG gas in the storage tank 6 that has absorbed cold energy and turned into a higher temperature is sent to the BOG compressor unit through the twelfth pipeline 24.

[0045] Preferably, the eleventh pipeline 23 is also connected to a ventilation tube.

[0046] The BOG compressor unit includes a primary BOG compressor 29 and a secondary BOG compressor 30. The air inlet of the primary BOG compressor 29 is connected to the cold side outlet of the heat exchanger 4 through the twelfth pipeline 24, the air outlet of the primary BOG compressor 29 is connected to the second hot side inlet of the heat exchanger 4 through the thirteenth pipeline 25, the second hot side outlet of the heat exchanger 4 is connected to the air inlet of the secondary BOG compressor 30 through the fourteenth pipeline 26, the air outlet of the secondary BOG compressor 30 is connected to the third hot side inlet of the heat exchanger 4 through the fifteenth pipeline 27, and the third hot side outlet of the heat exchanger 4 is connected to the air inlet of the dual-fuel engine 1 through the sixteenth pipeline 20.

[0047] Preferably, a first three-way control valve A is provided on the thirteenth pipeline 25, and one of the outlets of the first three-way control valve A is connected to the air inlet of the secondary BOG compressor 30 through a pipeline;

[0048] A second three-way control valve B is provided on the fifteenth pipeline 27 , and one of the outlets of the second three-way control valve B is connected to the air intake of the dual-fuel engine 1 through a pipeline.

[0049] In this embodiment, the heat exchanger is a gas / gas heat exchanger, and the absorbent used in the absorption tower is an organic amine solution.

[0050] Preferably, the CO 2 The capture unit also includes a reheater 28 for reheating the undesorbed rich liquid in the desorption tower 9 (heat exchange is performed with the high-temperature lean liquid in the heat exchanger 10, and the high-temperature rich liquid that absorbs the heat in the high-temperature lean liquid enters the desorption tower 9 to desorb CO 2 However, there is still some high-temperature rich liquid that has not been desorbed, so this part of the high-temperature rich liquid needs to enter the reheater 28 for reheating. The reheated rich liquid flows back to the desorption tower to fully release CO 2 , to improve the desorption rate of the rich liquid; the exhaust gas of the dual-fuel engine 1 can also be heated, and the exhaust gas is transported to the exhaust gas inlet at the lower part of the absorption tower 8 after heating.

[0051] The gas supply and carbon capture system of the present invention fully utilizes the cold energy of BOG from the LNG tank to cool the BOG compressed by the BOG compressor, so no additional intercooler, aftercooler, and fresh water cooling system are required; the heat energy of the compressed BOG and the compressed CO2 is fully utilized to heat the BOG from the LNG tank so that the temperature entering the BOG compressor reaches the intake temperature requirement of the normal temperature compressor, so the BOG compressor can use a normal temperature compressor; the heat energy of the exhaust gas of the dual-fuel engine is fully utilized to heat the rich liquid, so no additional heating medium and heat source are required; the cold energy of the BOG from the LNG tank is fully utilized to liquefy CO2, so no additional cooling medium and cold source are required.

[0052] It should be clear that the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

Claims

1. A gas supply and carbon capture system, characterized in that: Including LNG tank, BOG compressor unit, dual-fuel engine, CO2 capture unit, CO2 compressor, heat exchanger, CO2 storage tank, The CO2 capture unit is used to desorb CO2 from the exhaust gas of the dual-fuel engine by chemical absorption and deliver it to the CO2 compressor; The CO2 compressor is used to pressurize the desorbed CO2 and send the pressurized CO2 to the first hot side end of the heat exchanger; The LNG tank is used to store liquid LNG and the BOG gas formed on the top of the tank is fed into the cold side of the heat exchanger; The heat exchanger is used to exchange heat between the pressurized CO2 and the BOG gas, utilize the cold energy of the BOG gas to liquefy the CO2, and store the obtained liquid CO2 in the CO2 storage tank, and the formed BOG gas with a higher temperature is sent to the BOG compressor unit; The BOG compressor unit is used to pressurize the BOG gas with a relatively high temperature and then deliver it to the dual-fuel engine for combustion. The BOG compressor unit adopts a normal temperature compressor.

2. The gas supply and carbon capture system according to claim 1, characterized in that: The CO2 capture unit includes an absorption tower, a desorption tower, a heat exchanger, a rich liquid pump and a lean liquid pump. The gas outlet of the dual-fuel engine is connected to the exhaust gas inlet at the bottom of the absorption tower through a pipeline. The exhaust gas of the dual-fuel engine reacts with the absorbent sprayed from the top of the tower and is absorbed in the absorption tower. The remaining gas after decarbonization is discharged from the top of the absorption tower, and the low-temperature rich liquid formed by the reaction is pumped out from the bottom of the tower by a rich liquid pump and sent to the cold side inlet of the heat exchanger. The rich liquid flowing out from the cold side outlet of the heat exchanger flows into the desorption tower from the rich liquid inlet at the top of the desorption tower. After being heated to the set temperature in the desorption tower, CO2 is desorbed and the rich liquid is regenerated into high-temperature lean liquid. The high-temperature lean liquid is pumped out from the bottom of the tower by the lean liquid pump and sent to the hot side inlet of the heat exchanger. Heat exchange is carried out with the low-temperature rich liquid in the heat exchanger. The desorbed CO2 is discharged from the top of the tower and is transported to the CO2 compressor after drying and dehydration.

3. The gas supply and carbon capture system according to claim 2, characterized in that: The CO2 capture unit further comprises a reheater for reheating the undesorbed rich liquid in the desorption tower.

4. The gas supply and carbon capture system according to claim 2, characterized in that: The absorbent used in the absorption tower is an organic amine solution.

5. The gas supply and carbon capture system according to claim 1, characterized in that: The BOG compressor unit comprises a primary BOG compressor and a secondary BOG compressor, wherein an air inlet of the primary BOG compressor is connected to a cold side outlet of a heat exchanger, an air outlet of the primary BOG compressor is connected to a second hot side inlet of the heat exchanger, the second hot side outlet of the heat exchanger is connected to an air inlet of the secondary BOG compressor, an air outlet of the secondary BOG compressor is connected to a third hot side inlet of the heat exchanger, and the third hot side outlet of the heat exchanger is connected to an air inlet of the dual-fuel engine.

6. The gas supply and carbon capture system according to claim 5, characterized in that: A first three-way control valve is provided on the pipeline connecting the air outlet of the first-stage BOG compressor and the inlet of the second hot side end of the heat exchanger, and one of the outlets of the first three-way control valve is connected to the air inlet of the second-stage BOG compressor through a pipeline; A second three-way control valve is provided on the pipeline connecting the air outlet of the secondary BOG compressor and the third hot side inlet of the heat exchanger, and one outlet of the second three-way control valve is connected to the air inlet of the dual-fuel engine through a pipeline.

7. The gas supply and carbon capture system according to claim 1, characterized in that: A vent pipe is also connected to the pipeline connecting the first hot side end gas outlet of the heat exchanger and the liquid inlet of the CO2 storage tank.

8. The gas supply and carbon capture system according to claim 1, characterized in that: The heat exchanger is a gas / gas heat exchanger.

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