Methanol power CO2 transport ship fuel inerting and filling treatment system and method

Abstract

The invention provides a methanol power CO2 transport ship fuel inerting and filling treatment system and method. The system comprises a methanol fuel supply system, a BOG inerting system and a methanol fuel filling system. According to the invention, BOG generated by heat exchange between liquid CO2 in the ship CO2 storage tank and the outside is ingeniously utilized as inert gas and is introduced into the fuel cabin and the daily cabinet, so that explosion caused by the fact that outside air enters the fuel cabin and the daily cabinet is avoided. According to the invention, an inert gas generator is omitted, the cost of equipping the inert gas generator and the operation cost are reduced, and the economical efficiency is good; and in addition, harmful methanol gas discharged from the fuel cabin during methanol fuel filling is introduced into the GCU unit for combustion, so that environmental pollution and explosion risks possibly caused when the methanol gas is discharged into the atmosphere are avoided, and relatively high practicability and environmental friendliness are achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of ships, and in particular relates to a fuel inerting and filling processing system and method for a methanol-powered CO2 transport ship. Background Art

[0002] In recent years, the International Maritime Organization (IMO) has increasingly stringent requirements for ship carbon emission reduction, and carbon capture and storage technology (CCS technology for short) is the main technical means to achieve this requirement. CCS technology is to transport the captured CO2 gas to a specific location for storage, such as Iceland storage, deep sea storage, etc. For the above storage involving long-distance transportation at sea, CO2 transport ships are needed to achieve this process.

[0003] As the requirements for carbon emission reduction in ships become higher and higher, traditional fuel can no longer meet the requirements of carbon emission. Using clean energy to replace traditional fuel has become a hot topic in the shipbuilding field. Methanol, as a kind of clean energy, has lower carbon emissions than traditional fuel, which is in line with the concept of carbon emission reduction. Due to the low calorific value of methanol, about 19.6MJ / kg, and the density of about 791kg / m 3 The calorific value of traditional fuel oil is about 42MJ / kg and the density is about 980kg / m 3 , which means that if the two are to achieve the same calorific value, the volume of methanol fuel required by the ship is about 2.6 times the volume of traditional fuel oil. During the transportation process, the methanol-powered CO2 transport ship burns 30t to 60t of methanol fuel every day. In the future, the larger the ship type, the more methanol fuel will be burned. Therefore, the amount of methanol fuel carried by ships transporting CO2 over long distances will increase greatly. Since methanol has a low flash point (about 11°C) and is a highly flammable fuel, it is necessary to inertize the daily cabinets and fuel tanks. Usually, the daily cabinets and fuel tanks need to use an inert gas generator to generate nitrogen for inerting, but the manufacturing process of nitrogen is relatively complicated, which not only requires specialized personnel to be responsible for equipment operation and management, but also has a high cost.

[0004] During the ship transportation, CO2 is usually stored in C-type tanks in liquid form. The storage temperature of liquid CO2 is usually -20 to -50℃, and the pressure is 0.7 to 1.5MPa, which leads to a large temperature difference between the CO2 tank and the external environment. Therefore, CO2 boil-off gas (BOG) will inevitably be produced. For CO2 transport ships with longer transport routes, more BOG will be produced. When the pressure of BOG in the CO2 tank reaches a certain level, the safety valve will be opened. Therefore, BOG must be processed. Usually, BOG of CO2 is processed by reliquefaction of the refrigeration system. Of course, if BOG can be used externally, it can also avoid excessive pressure in the CO2 tank.

[0005] As we all know, CO2 also meets the conditions of being an inert gas, so BOG can be passed into the fuel tank and daily cabinet for inerting treatment. In this way, the ship does not need to be equipped with an inert gas generator, which reduces costs and makes reasonable use of BOG.

[0006] At the same time, methanol is extremely volatile. For CO2 transport ships that run long routes, the volume of methanol fuel required to be filled is large. Therefore, during the process of filling methanol fuel, the ship will discharge harmful methanol gas of the same volume as the methanol fuel. If it is discharged directly into the atmosphere, it may cause environmental pollution and the risk of explosion. Therefore, the treatment of methanol gas has become a problem that needs to be solved.

[0007] In summary, if a fuel inerting and filling treatment system for a methanol-powered CO2 transport ship can be designed, the BOG of CO2 in the ship's CO2 storage tank can be used as an inert gas to inert the fuel tank and daily cabinet to maintain a certain positive pressure of the inert gas inside the two, thereby preventing outside air from entering the fuel tank and daily cabinet to cause an explosion. In addition, there is no need to equip the ship with a separate inert gas generator, which saves the equipment cost and operating cost of the inert gas generator and has good economy. Summary of the invention

[0008] The present invention substantially solves the above problems and proposes a methanol-powered CO2 transport ship fuel inerting and filling processing system and method. The first purpose of the present invention is to propose a methanol-powered CO2 transport ship fuel inerting and filling processing system, which consists of three systems: a methanol fuel supply system, a BOG inerting system and a methanol fuel filling system.

[0009] The methanol fuel supply system comprises: a fuel tank, a transfer pump, a daily cabinet, a booster pump, and a heating unit.

[0010] The BOG inerting system includes: a CO2 storage tank, a primary pressure reducing valve, a cold storage system, an air conditioning system, a secondary pressure reducing valve, a pressure sensor, a daily cabinet valve, a daily cabinet, a daily cabinet safety valve, a fuel tank valve, a fuel tank, and a fuel tank safety valve.

[0011] The methanol fuel filling system comprises: a fuel tank, a stop valve, and a GCU unit.

[0012] In the methanol fuel supply system, the fuel tank, transfer pump, daily cabinet, booster pump, and heating unit are sequentially connected through pipelines and finally delivered to the power unit.

[0013] In the BOG inerting system, the CO2 storage tank is a semi-cold and semi-pressure double C-type tank, which is connected with the first-level pressure reducing valve, cold storage system, air conditioning system, second-level pressure reducing valve and pressure sensor in sequence through pipelines; the first-level pressure reducing valve is used to preliminarily reduce the pressure of BOG; the second-level pressure reducing valve is used to reduce the pressure of BOG to 0.15 bar; the pressure sensor is connected with the daily cabinet valve through a pipeline; the daily cabinet valve is connected with the daily cabinet; a daily cabinet safety valve is provided on the top of the daily cabinet; the pressure sensor is connected with the fuel tank valve through another pipeline; the fuel tank valve is connected with the fuel tank; a fuel tank safety valve is provided on the top of the fuel tank.

[0014] In the methanol fuel filling system, the fuel tank, the stop valve, and the GCU unit are connected in sequence through pipelines.

[0015] The second object of the present invention is to provide a method for inerting and filling fuel for a methanol-powered CO2 transport ship.

[0016] When the ship is sailing, in the BOG inerting system, the BOG in the CO2 storage tank is decompressed by the first-level pressure reducing valve, and then passes through the cold storage system and the air-conditioning system in turn. Then, the BOG is decompressed to 0.15 bar by the second-level pressure reducing valve, and the daily cabinet valve is opened, and the BOG enters the daily cabinet, so that the pressure of the daily cabinet is maintained at about 0.15 bar. When an abnormal situation occurs in the daily cabinet and the pressure reaches 0.2 bar, the safety valve of the daily cabinet automatically opens and the excess gas is discharged into the atmosphere.

[0017] When the fuel tank delivers fuel to the daily cabinet, the BOG in the CO2 storage tank is decompressed by the first-level pressure reducing valve, and then passes through the cold storage system and the air-conditioning system in turn. Then, the BOG is decompressed to 0.15 bar by the second-level pressure reducing valve, and the fuel tank valve is opened, and the BOG enters the fuel tank, so that the pressure of the fuel tank is maintained at about 0.15 bar. When an abnormal situation occurs in the fuel tank and the pressure reaches 0.2 bar, the fuel tank safety valve automatically opens and the excess gas is discharged into the atmosphere.

[0018] When the ship is refueled with methanol fuel, the external methanol fuel enters the fuel tank through the pipeline, the stop valve is opened, and the harmful methanol gas generated in the fuel tank enters the GCU unit for combustion.

[0019] Beneficial effects of the present invention:

[0020] 1. The present invention utilizes BOG generated in the CO2 storage tank of the CO2 transport ship as an inert gas to inertize the methanol fuel tank and the daily cabinet. The present invention can save the inert gas generator for the methanol fuel supply system, save the equipment cost and operation cost of the inert gas generator, and fully utilize the cold energy of BOG during the inerting process, which has good economic efficiency.

[0021] 2. The present invention passes the methanol gas discharged from the fuel tank when the methanol fuel is added into the GCU unit for centralized combustion, thus avoiding the environmental pollution and explosion risks that may be caused by the discharge of methanol gas, and has good practicality and environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Attached Figure 1 is a system diagram of the present invention;

[0023] Attached Figure 2 This is a schematic diagram of the distribution of CO2 storage tanks on ships;

[0024] In the attached figure: 1. CO2 storage tank; 2. First-stage pressure reducing valve; 3. Cold storage system; 4. Air conditioning system; 5. Second-stage pressure reducing valve; 6. Pressure sensor; 7. Daily cabinet valve; 8. Daily cabinet; 9. Daily cabinet safety valve; 10. Booster pump; 11. Heating unit; 12. Fuel tank valve; 13. Fuel tank; 14. Fuel tank safety valve; 15. Transfer pump; 16. Stop valve; 17. GCU unit. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0026] A methanol powered CO2 transport ship fuel inerting and filling processing system and method, such as Figure 1 , Figure 2 As shown, the system consists of three subsystems: methanol fuel supply system, BOG inerting system and methanol fuel filling system.

[0027] The methanol fuel supply system includes: a fuel tank 13, a transfer pump 15, a daily cabinet 8, a booster pump 10, and a heating unit 11.

[0028] The BOG inerting system includes: a CO2 storage tank 1, a primary pressure reducing valve 2, a cold storage system 3, an air conditioning system 4, a secondary pressure reducing valve 5, a pressure sensor 6, a daily cabinet valve 7, a daily cabinet 8, a daily cabinet safety valve 9, a fuel tank valve 12, a fuel tank 13, and a fuel tank safety valve 14.

[0029] The methanol fuel filling system includes: a fuel tank 13 , a stop valve 16 , and a GCU unit 17 .

[0030] In the methanol fuel supply system, the fuel tank 13, the transfer pump 15, the daily cabinet 8, the booster pump 10, and the heating unit 11 are sequentially connected through pipelines and finally delivered to the power unit.

[0031] In the BOG inerting system, the CO2 storage tank 1 is a semi-cold and semi-pressure double C-type tank, which is connected to the primary pressure reducing valve 2, the cold storage system 3, the air conditioning system 4, the secondary pressure reducing valve 5, and the pressure sensor 6 in sequence through pipelines; the primary pressure reducing valve 2 is used to preliminarily reduce the pressure of BOG; the secondary pressure reducing valve 5 is used to reduce the pressure of BOG to 0.15 bar; the pressure sensor 6 is connected to the daily cabinet valve 7 through a pipeline; the daily cabinet valve 7 is connected to the daily cabinet 8; a daily cabinet safety valve 9 is provided on the top of the daily cabinet 8; the pressure sensor 6 is connected to the fuel tank valve 12 through another pipeline; the fuel tank valve 12 is connected to the fuel tank 13; and a fuel tank safety valve 14 is provided on the top of the fuel tank 13.

[0032] In the methanol fuel filling system, the fuel tank 13, the stop valve 16, and the GCU unit 17 are connected in sequence through pipelines.

[0033] When methanol fuel is supplied, the methanol fuel stored in the fuel tank 13 is transferred out by the transfer pump 15 and enters the daily cabinet 8, and then passes through the booster pump 10 and the heating unit 11 in sequence to be heated to the intake temperature required by the power device, and finally supplied to the power device for ship propulsion.

[0034] When the ship is sailing, in the BOG inerting system, the BOG generated by the heat exchange between the liquid CO2 stored in the CO2 storage tank 1 and the outside world passes through the cold storage system 3 and the air conditioning system 4 in turn through the first-level pressure reducing valve 2, and the cold energy released by the BOG is utilized in the cold storage system 3 and the air conditioning system 4. Then, the BOG is reduced to 0.15 bar through the second-level pressure reducing valve 5. At this time, the daily cabinet valve 7 is opened, the fuel tank valve 12 is closed, and the BOG enters the daily cabinet 8, so that the pressure of the daily cabinet 8 is maintained at about 0.15 bar. When an abnormal situation occurs in the daily cabinet 8 and the pressure reaches 0.2 bar, the daily cabinet safety valve 9 is automatically opened, and the excess gas is discharged into the atmosphere.

[0035] When the fuel tank 13 delivers methanol fuel to the daily cabinet 8, the BOG of CO2 is depressurized by the primary pressure reducing valve 2, and then passes through the cold storage system 3 and the air conditioning system 4 in sequence, and the cold energy released by the BOG is utilized in the cold storage system 3 and the air conditioning system 4. Then, the BOG is depressurized to 0.15 bar by the secondary pressure reducing valve 5, the fuel tank valve 12 is opened, the daily cabinet valve 7 is closed, and the BOG enters the fuel tank 13, so that the pressure of the fuel tank 13 is maintained at about 0.15 bar. When an abnormal situation occurs in the fuel tank 13 and the pressure reaches 0.2 bar, the fuel tank safety valve 14 is automatically opened, and the excess gas is discharged into the atmosphere.

[0036] During the methanol filling process, when external methanol fuel enters the fuel tank 13 through the filling pipe, the stop valve 16 is opened, and the harmful methanol gas generated in the fuel tank 13 enters the GCU unit 17 through the pipe for combustion, preventing the methanol gas from being discharged into the atmosphere.

[0037] During the ship transportation process, the temperature difference between the ship's CO2 storage tank 1 and the external environment is large, so it is inevitable to produce CO2 boil-off gas (abbreviated as BOG), and for CO2 transport ships with longer transportation routes, more BOG will be produced. The present invention cleverly uses CO2 BOG as an inert gas, and after further utilizing the cold energy of BOG itself, it is passed into the fuel tank 13 and the daily cabinet 8 for inerting to maintain a certain positive pressure of the inert gas inside the two, and prevents the outside air from entering the fuel tank 13 and the daily cabinet 8 to cause an explosion. The present invention does not need to be equipped with an inert gas generator separately on the ship, saving the equipment cost and operating cost of the inert gas generator, and has good economy.

[0038] In the process of methanol fuel filling, the methanol fuel enters the fuel tank 13, and harmful methanol gas of the same volume as the methanol fuel is discharged from the fuel tank 13 and passed into the GCU unit 17 for centralized combustion, thereby avoiding the pollution and explosion risks caused by the methanol gas being discharged into the atmosphere. Usually, a ship needs to fill hundreds to thousands of cubic meters of methanol fuel each time, which will also produce hundreds to thousands of cubic meters of methanol gas. Therefore, the methanol gas treatment is of great significance and has good practicality and environmental protection.

[0039] The attached drawings of the present invention only show the connection and matching relationship between different components, and the actual positions on the ship are arranged at reasonable positions after comprehensive consideration based on the actual design requirements of the ship.

[0040] The above is only a preferred embodiment of the present invention. The specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A fuel inerting and filling treatment system for a methanol-powered CO2 transport ship, characterized in that: The system comprises a CO2 storage tank (1), a primary pressure reducing valve (2), a cold storage system (3), an air conditioning system (4), a secondary pressure reducing valve (5), a pressure sensor (6), a daily cabinet valve (7), a daily cabinet (8), a daily cabinet safety valve (9), a booster pump (10), a heating unit (11), a fuel tank valve (12), a fuel tank (13), a fuel tank safety valve (14), a transfer pump (15), a stop valve (16), and a GCU unit (17). The CO2 storage tank (1) is a semi-cold and semi-pressure double C-type tank, which is connected to a primary pressure reducing valve (2), a cold storage system (3), an air conditioning system (4), a secondary pressure reducing valve (5), and a pressure sensor (6) in sequence through pipelines. The pressure sensor (6) is connected to a daily cabinet valve (7) through a pipeline. The daily cabinet valve (7) is connected to a daily cabinet (8). A daily cabinet safety valve (9) is provided on the top of the daily cabinet (8). The pressure sensor (6) is connected to a fuel tank valve (12) through another pipeline. The fuel tank valve (12) is connected to a fuel tank (13). A fuel tank safety valve (14) is provided on the top of the fuel tank (13). The fuel tank (13), a stop valve (16), and a GCU unit (17) are connected in sequence through pipelines. The fuel tank (13), a transfer pump (15), a daily cabinet (8), a booster pump (10), and a heating unit (11) are connected in sequence through pipelines and are finally delivered to a power unit.

2. A method for inerting and filling fuel for a methanol-powered CO2 transport ship based on the system of claim 1, characterized in that: When the ship is sailing, the BOG generated by the heat exchange between the CO2 in the CO2 storage tank (1) and the outside is reduced in pressure by the first pressure reducing valve (2), and then passes through the cold storage system (3) and the air conditioning system (4) in turn, and the cold energy released by the BOG is utilized in the cold storage system (3) and the air conditioning system (4). Then, the pressure is reduced to 0.15 bar by the second pressure reducing valve (5) and enters the daily cabinet (8), so that the pressure of the daily cabinet (8) is maintained at about 0.15 bar. When an abnormal situation occurs in the daily cabinet (8) and the pressure reaches 0.2 bar, the safety valve (9) of the daily cabinet automatically opens, and the excess gas is discharged into the atmosphere. When the fuel tank (13) delivers fuel to the daily cabinet (8), the BOG is decompressed by the primary pressure reducing valve (2), and then passes through the cold storage system (3) and the air conditioning system (4) in sequence, and the cold energy released by the BOG is utilized in the cold storage system (3) and the air conditioning system (4). Then, the BOG is decompressed to 0.15 bar by the secondary pressure reducing valve (5) and enters the fuel tank (13), so that the pressure of the fuel tank (13) is maintained at about 0.15 bar. When an abnormal situation occurs in the fuel tank (13) and the pressure reaches 0.2 bar, the fuel tank safety valve (14) automatically opens, and the excess gas is discharged into the atmosphere.

3. The method for inerting and filling fuel for a methanol-powered CO2 transport ship according to claim 2, characterized in that: During the methanol filling process, when external methanol fuel enters the fuel tank (13) through the pipeline, the stop valve (16) is opened, and the methanol gas generated in the fuel tank (13) enters the GCU unit (17) through the pipeline for combustion.

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