Ammonia fuel power bulk carrier fuel and CO2 storage system and method

Abstract

The invention belongs to the technical field of ships, and provides an ammonia fuel power bulk carrier fuel and CO2 storage system and method. The system comprises a C-shaped tank, a multifunctional tank, an ammonia pump, a fuel oil pump, an ammonia valve, a fuel oil valve, a CO2 valve, a three-way valve, a fuel oil cabin, a void cabin, a carbon capture unit and a CO2 liquefaction unit. According to the method, the ammonia fuel or the marine fuel is flexibly selected to be added according to the current berthing port fuel adding condition, the ammonia fuel is preferentially combusted during sailing, the marine fuel is added at a port without the ammonia fuel adding condition (a marine fuel and carbon capture mode is adopted during sailing), the problem that the current ammonia fuel power bulk cargo ship is difficult to add fuel is solved, and the energy consumption is reduced. Large-scale application of ammonia fuel on ships is promoted, and meanwhile the strict requirement of IMO for tail gas emission is met. Besides, the ammonia fuel or the CO2 is stored by adopting a multifunctional tank by utilizing similar storage conditions of the ammonia fuel and the liquid CO2 and a void cabin of the ship, and the common problem that the storage space of the ammonia fuel and the CO2 is large in demand and high in requirement is solved through ingenious combination.

Description

Technical Field

[0001] The present invention belongs to the technical field of ships, and relates to a fuel and CO2 storage system and method for an ammonia fuel-powered bulk carrier. Background Art

[0002] Currently, the International Maritime Organization (IMO) has increasingly strict standards for ship exhaust emissions, forcing more and more bulk carriers to use ammonia fuel as the power source. As a relatively ideal carbon-free fuel for ships, the calorific value of ammonia fuel is very low compared to that of marine fuel oil. The calorific value of marine fuel oil is 43 MJ / kg, and the density is 980 kg / m 3 , while the calorific value of ammonia fuel is only 18.6 MJ / kg, and the density is only 617 kg / m 3 . Therefore, to achieve the same calorific value, the volume of ammonia fuel required is about 4 times that of marine fuel oil, and the volume of the required fuel tank is also larger accordingly. To reduce the storage volume of ammonia fuel on ships, it is usually stored in liquid form (liquid ammonia) under normal pressure and at -33°C. Moreover, ammonia fuel has characteristics such as being flammable, explosive, and corrosive, and has high requirements for ammonia fuel storage. It cannot be set in the "corners" of the hull like a fuel oil tank. A special fuel tank needs to be set in a relatively wide and safe space on the ship to store ammonia fuel. Therefore, ammonia fuel storage occupies a large amount of valuable space on ships.

[0003] An ammonia fuel engine refers to a dual-fuel engine that uses a mixture of ammonia fuel and marine fuel oil. This engine can either burn ammonia fuel and marine fuel oil simultaneously (marine fuel oil as the pilot fuel) or burn only marine fuel oil alone. With the gradual popularization of ammonia fuel power in the field of bulk carriers, it is currently in the initial stage of ammonia fuel application. Only a few developed ports in the world have the conditions to refuel ammonia fuel, while most ports do not have such conditions. However, any port in the world can refuel marine fuel oil. Bulk carriers usually have long voyages and their calling ports are not fixed. If the ammonia fuel is insufficient during navigation and cannot be replenished at the calling port, the ship needs to switch to marine fuel power to continue sailing. Therefore, ammonia fuel faces the problem of difficult ammonia fuel refueling during the use of bulk carriers.

[0004] When a bulk carrier burns marine fuel during navigation, a large amount of greenhouse gases such as CO2 will be generated. In order to meet the requirements of the International Maritime Organization for ship exhaust emissions, the bulk carrier needs to be equipped with a carbon capture device to capture CO2 and store the captured CO2 in a liquefied state on the ship. Usually, bulk carriers vary in size and burn about 30 to 60 tons of fuel per day. Burning 1 ton of marine fuel will generate 3.8 tons of CO2. The bulk carrier burning marine fuel will generate a very large amount of CO2 every day. Therefore, a large amount of CO2 requires a very large storage space. The bulk carrier burning marine fuel will generate a very large amount of CO2 every day, and a decarbonization device is needed to capture and liquefy a large amount of CO2, resulting in huge power consumption, which will not only increase the workload of the decarbonization device, but also generate many additional operating costs and personnel management costs. In order to reduce the storage volume of CO2, it is usually stored in a liquid state. At present, ships often use a semi-cooling and semi-pressure method to store CO2 in a C-type tank (the working pressure is between 0.7 MPa and 1.5 MPa, and the working temperature is between -50 °C and -20 °C). It can be seen that this C-type tank not only meets the storage conditions of CO2, but also meets the storage conditions of liquid ammonia.

[0005] Currently, the storage of both ammonia fuel and CO2 requires a relatively large amount of space. Nowadays, many bulk carriers have changed the upper and lower independent ballast tanks to upper and lower through-tank ballast tanks. Through this design, the amount of water loaded in a single ballast tank is more than that in a single upper and lower independent ballast tank. Fewer upper and lower through-tank ballast tanks can meet the same ballast requirements. Therefore, void spaces will be generated during the design of the upper and lower through-tank ballast tanks, and the void spaces provide a reasonable space for the ship to store ammonia fuel or CO2.

[0006] Based on the current situation that the application of ammonia fuel in the initial stage of development faces difficulties in fuel filling, and at the same time the shipping industry urgently needs to promote the rapid application of ammonia fuel on ships and meet the requirements of IMO for ship exhaust emissions and other complex backgrounds, if a fuel and CO2 storage system and method for an ammonia fuel-powered bulk carrier can be proposed, during sea navigation, by burning ammonia fuel and burning marine fuel with carbon capture in two modes, it solves the current dilemma of difficult fuel filling for ammonia fuel-powered bulk carriers, promotes the large-scale application of ammonia fuel on ships, and at the same time can meet the stringent requirements of the International Maritime Organization for exhaust emissions. Summary of the Invention

[0007] The object of the present invention is to address the above-mentioned problems and propose a fuel and CO2 storage system and method for an ammonia fuel-powered bulk carrier. A fuel and CO2 storage system for an ammonia fuel-powered bulk carrier according to the present invention mainly consists of a C-type tank, a multi-functional tank, an ammonia pump, a fuel pump, an ammonia valve, a fuel valve, a CO2 valve, a three-way valve, a fuel tank, a void space, a main engine, a carbon capture unit, and a CO2 liquefaction unit.

[0008] The C-type tank is a storage tank with a thermal insulation layer, corrosion resistance and a certain pressure-bearing capacity. The C-type tank is cylindrical in the middle and hemispherical at both ends. The multi-functional tank consists of three C-type tanks arranged one above the other in sequence. The middle of each C-type tank is connected into a whole through pipelines, and it can store ammonia fuel and liquid CO2. The multi-functional tank is placed in the empty cabins of the ship. The empty cabins are located on both sides of the ship's hull.

[0009] The ammonia pump is placed at the bottom of the lowermost C-type tank in the multi-functional tank and is used to barge ammonia fuel. The fuel pump is placed at the bottom of the fuel tank and is used to barge marine fuel.

[0010] The ammonia pump in the multi-functional tank is connected to an ammonia valve, a main engine, and a three-way valve in sequence through pipelines, and the generated tail gas is discharged to the atmosphere for treatment. The fuel pump in the fuel tank is connected to a fuel valve, a main engine, a three-way valve, a carbon capture unit, a CO2 liquefaction unit, a CO2 valve, and the multi-functional tank in sequence through pipelines.

[0011] During navigation, ammonia fuel is preferentially burned. The ammonia fuel in the multi-functional tank is barged out through the ammonia pump and supplied to the main engine for combustion through the ammonia valve. At the same time, a small amount of marine fuel is also supplied to the main engine as pilot fuel. The side of the three-way valve leading to the atmosphere is opened. Since ammonia fuel is a carbon-free fuel, the exhaust gas generated by the main engine is discharged to the atmosphere for treatment through the three-way valve.

[0012] After the ammonia fuel in the multi-functional tank is burned out, the ship starts to burn marine fuel. The marine fuel in the fuel tank is barged out through the fuel pump and supplied to the main engine for combustion through the fuel valve. The side of the three-way valve connected to the carbon capture unit is opened. The tail gas generated by the ship's main engine passes through the three-way valve and enters the carbon capture unit and the CO2 liquefaction unit. The carbon capture unit separates CO2 from other gases in the ship's tail gas, and the other gases are directly discharged into the atmosphere, while CO2 is collected and transported to the CO2 liquefaction unit through pipelines. The CO2 liquefaction unit liquefies the captured CO2, and the liquefied CO2 is stored in the empty multi-functional tank through pipelines after passing through the CO2 valve. When the ship arrives at the next berthing port, the CO2 stored in the multi-functional tank is discharged at the berthing port, and the multi-functional tank is vacated to store ammonia fuel or CO2.

[0013] To keep the hull balanced and prevent it from tilting to the left or right, the ammonia fuel in the multi-functional tanks in the left and right empty cabins is burned alternately in sequence. Similarly, the CO2 captured by burning marine fuel is also stored in the multi-functional tanks in the left and right empty cabins alternately in sequence.

[0014] The second object of the present invention is to propose a fuel and CO2 storage method for an ammonia-fueled bulk carrier. To solve the problem that bulk carriers face difficulties in refueling ammonia fuel at berthing ports, according to the fuel refueling conditions at the berthing ports, ammonia fuel or marine fuel is flexibly selected for refueling. During navigation, ammonia fuel is preferentially burned. At ports without ammonia fuel refueling conditions, marine fuel is refueled. After the ammonia fuel is exhausted, the ship starts burning marine fuel to sail to the next berthing port.

[0015] First, before the ship sails, calculate whether the existing ammonia fuel in the ship's multi-functional tank and the existing marine fuel in the fuel oil tank can reach the next berthing port and make a judgment. If it can reach the next berthing port, make a judgment based on whether the multi-functional tank is fully filled with ammonia fuel. If the multi-functional tank is fully filled with ammonia fuel, sail to the next berthing port by burning ammonia fuel; if the multi-functional tank is not fully filled with ammonia fuel, make a judgment based on whether ammonia fuel can be refueled at this berthing port. If ammonia fuel can be refueled, fill the unfilled multi-functional tank with ammonia fuel and sail to the next berthing port by burning ammonia fuel; if ammonia fuel cannot be refueled, preferentially burn ammonia fuel during navigation and then burn marine fuel to sail to the next berthing port, and store the captured CO2 in the empty multi-functional tank.

[0016] If the existing ammonia fuel and marine fuel on the ship cannot reach the next berthing port, make a judgment based on whether ammonia fuel can be refueled at this berthing port. If ammonia fuel can be refueled at this berthing port, refuel ammonia fuel and sail to the next berthing port by burning ammonia fuel; if ammonia fuel cannot be refueled, marine fuel needs to be refueled. Preferentially burn ammonia fuel during navigation. After the ammonia fuel is exhausted, then burn marine fuel to sail to the next berthing port, and store the captured CO2 in the empty multi-functional tank.

[0017] After the ship arrives at the next berthing port, make a judgment based on whether the berthing port is the destination port. If the berthing port is the destination port, this shipping route ends; if the berthing port is not the destination port, continue sailing to the next berthing port according to this method to select fuel refueling.

[0018] Whether the ammonia fuel in the multi-functional tank and the marine fuel in the fuel oil tank can reach the next berthing port can be based on the ratio of the total heat released by the existing ammonia fuel and marine fuel on the ship currently (M 氨 q 氨 +M 油 q 油 ) to the energy required under the average daily operating power of the ship 24P / η, so as to obtain the relationship formula with the number of sailing days, as shown in formula (Ⅰ).

[0019]

[0020] M 氨is the mass of ammonia fuel in the multi-purpose tank, kg;

[0021] q 氨 is the calorific value of ammonia fuel, 18.6MJ / kg;

[0022] M 油 is the mass of marine fuel in the fuel tank, kg;

[0023] q 油 is the calorific value of marine fuel, 42MJ / kg;

[0024] P is the average operating power of the ship's main engine, W;

[0025] η is the efficiency of the diesel engine, usually 45% to 50%;

[0026] T is the number of days the ship sails;

[0027] μ is the margin coefficient, usually ranging from 1.2 to 1.5. The longer the route, the smaller the value, and the shorter the route, the larger the value.

[0028] Beneficial effects of the present invention:

[0029] 1. The system and method of the present invention can flexibly select ammonia fuel or marine fuel oil for filling according to the current fuel filling conditions of the berthing port, and give priority to burning ammonia fuel during navigation. Marine fuel oil is filled in ports without ammonia fuel filling conditions (marine fuel oil + carbon capture mode is used during sea navigation). This solves the current dilemma of fuel filling difficulties for ammonia fuel-powered bulk carriers, promotes the large-scale application of ammonia fuel on ships, and at the same time meets the International Maritime Organization's strict requirements on exhaust emissions.

[0030] 2. The present invention utilizes the similar storage conditions of ammonia fuel and liquid CO2 and the empty compartments existing in bulk carriers, and adopts multifunctional tanks to store both ammonia fuel and captured CO2. Through the ingenious combination of the present invention, the common problem of large and high space requirements for ammonia fuel storage and CO2 storage is solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a schematic diagram of the distribution of C-type tanks on ships;

[0032] Figure 2 This is a top view of a Type C tank on a bulk carrier;

[0033] Figure 3 This is the AA section view of the ship;

[0034] Figure 4 This is a schematic diagram of the internal connections of the multifunctional tank;

[0035] Figure 5 This is a system diagram of the present invention;

[0036] Figure 6 Flow chart of the method of the present invention;

[0037] In the attached drawings: 1. C-type tank; 2. Multi-functional tank; 3. Ammonia pump; 4. Fuel pump; 5. Ammonia valve; 6. Fuel valve; 7. CO2 valve; 8. Three-way valve; 9. Fuel tank; 10. Empty tank. Specific embodiments

[0038] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the attached drawings.

[0039] Based on the above problems, the first objective of the present invention is to propose a fuel and CO2 storage system for an ammonia-fueled bulk carrier. As Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 shown, the present invention includes a C-type tank 1, a multi-functional tank 2, an ammonia pump 3, a fuel pump 4, an ammonia valve 5, a fuel valve 6, a CO2 valve 7, a three-way valve 8, a fuel tank 9, an empty tank 10, a main engine, a carbon capture unit, and a CO2 liquefaction unit.

[0040] As Figure 1 shown, the C-type tank 1 is placed in the empty tank 10 of the ship.

[0041] As Figure 2 shown, the present invention defines that there are nine ballast tanks on each side of the ship's port and starboard, and there are three groups of symmetric and unused ballast tanks from the bow to the stern, that is, empty tanks 10. Among them, NO.3P, NO.3S, NO.5P, NO.5S, NO.7P, and NO.7S respectively represent the No. 3 port empty tank, the No. 3 starboard empty tank, the No. 5 port empty tank, the No. 5 starboard empty tank, the No. 7 port empty tank, and the No. 7 starboard empty tank.

[0042] As Figure 3 , Figure 4 shown, the C-type tank 1 is a storage tank with a heat-insulating layer, corrosion resistance and a certain pressure-bearing capacity. The shape of the C-type tank 1 is cylindrical in the middle and hemispherical at both ends; the multi-functional tank 2 is composed of three C-type tanks 1 arranged vertically in sequence, and the middle of each C-type tank 1 is connected into a whole through a pipeline. The ammonia pump 3 is placed at the bottom of the lowermost C-type tank 1 in the multi-functional tank 2. The multi-functional tank 2 is placed in the empty tank 10 of the ship, and the multi-functional tank 2 can store both ammonia fuel and liquid CO2.

[0043] For a better understanding of the present invention, since each multi-functional tank 2 is composed of three C-type tanks 1, Figure 5 the internal structure of the multi-functional tank 2 in

[0044] is not shown, and only the external shape is used to represent it.Figure 5 As shown, the ammonia pump 3 is placed at the bottom inside each multi-functional tank 2 for barge transporting ammonia fuel; the fuel oil pump 4 is placed at the bottom inside the fuel oil tank 9 for barge transporting marine fuel oil.

[0045] The ammonia pump 3 in the multi-functional tank 2 is connected to an ammonia valve 5, the main engine, and a three-way valve 8 in sequence through pipelines, and the generated tail gas is discharged to the atmosphere for treatment; the fuel oil pump 4 in the fuel oil tank 9 is connected to a fuel oil valve 6, the main engine, the three-way valve 8, a carbon capture unit, a CO2 liquefaction unit, a CO2 valve 7, and the multi-functional tank 2 in sequence through pipelines.

[0046] During navigation, ammonia fuel is preferentially burned. The ammonia fuel in the multi-functional tank 2 is barge transported out by the ammonia pump 3, supplied to the main engine for combustion through the ammonia valve 5. At the same time, a small amount of marine fuel oil is also supplied to the main engine as pilot fuel. The side of the three-way valve 8 leading to the atmosphere is opened. Since ammonia fuel is a carbon-free fuel, the exhaust gas generated by the main engine is discharged to the atmosphere for treatment through the three-way valve 8.

[0047] After the ammonia fuel in the multi-functional tank 2 is burned out, the ship starts to burn marine fuel oil. The marine fuel oil in the fuel oil tank 9 is barge transported out by the fuel oil pump 4 and supplied to the main engine for combustion through the fuel oil valve 6 through pipelines. The side of the three-way valve 8 connected to the carbon capture unit is opened. The tail gas generated by the ship's main engine passes through the three-way valve 8 and enters the carbon capture unit and the CO2 liquefaction unit. The carbon capture unit separates CO2 in the ship's tail gas from other gases, and the other gases are directly discharged into the atmosphere, while CO2 is collected and transported to the CO2 liquefaction unit through pipelines. The CO2 liquefaction unit liquefies the captured CO2, and the liquefied CO2 is stored in the empty multi-functional tank 2 through pipelines after passing through the CO2 valve 7. When the ship arrives at the next berthing port, the CO2 stored in the multi-functional tank 2 is discharged at the berthing port, making room for the multi-functional tank 2 to store ammonia fuel or CO2.

[0048] To maintain the balance of the hull and prevent it from tilting to the left or right, first burn a part of the ammonia fuel in the multi-functional tank 2 in the No. 3 left empty tank NO.3P, and then burn a part of the ammonia fuel in the multi-functional tank 2 in the No. 3 right empty tank NO.3S, and alternately burn the ammonia fuel in the multi-functional tank 2 in the left and right empty tanks in sequence. Similarly, burning marine fuel oil will generate a large amount of CO2. First, store a part of the captured CO2 in the multi-functional tank 2 in the No. 3 left empty tank NO.3P, and then store a part of the captured CO2 in the multi-functional tank 2 in the No. 3 right empty tank NO.3S, and alternately store it in the multi-functional tank 2 in the left and right empty tanks in sequence.

[0049] The second object of the present invention is to propose a fuel and CO2 storage method for an ammonia-fueled bulk carrier. To solve the problem that bulk carriers face difficulties in refueling ammonia fuel at berthing ports, according to the fuel refueling conditions at the berthing ports, ammonia fuel or marine fuel is flexibly selected for refueling. During navigation, ammonia fuel is preferentially burned. At ports without ammonia fuel refueling conditions, marine fuel is refueled. After the ammonia fuel is exhausted, the ship starts to burn marine fuel to sail to the next berthing port.

[0050] As Figure 6 shown, before the ship sails, the existing ammonia fuel in the ship's multi-functional tank 2 and the existing marine fuel in the fuel oil tank 9 are calculated at the berthing port. Whether the existing ammonia fuel in the multi-functional tank 2 and the existing marine fuel in the fuel oil tank 9 can reach the next berthing port is judged by formula (Ⅰ). If it can reach the next berthing port, it is judged according to whether the multi-functional tank 2 is fully filled with ammonia fuel. If the multi-functional tank 2 is fully filled with ammonia fuel, it sails to the next berthing port by burning ammonia fuel; if the multi-functional tank 2 is not fully filled with ammonia fuel, it is judged according to whether ammonia fuel can be refueled at the berthing port. If ammonia fuel can be refueled, the unfilled multi-functional tank 2 is filled with ammonia fuel, and it sails to the next berthing port by burning ammonia fuel; if ammonia fuel cannot be refueled, marine fuel does not need to be refueled. Ammonia fuel is preferentially burned. After the ammonia fuel is exhausted, marine fuel is burned to sail to the next berthing port, and the captured CO2 is stored in the empty multi-functional tank 2.

[0051] If the existing ammonia fuel and marine fuel of the ship cannot reach the next berthing port, it is judged according to whether ammonia fuel can be refueled at the berthing port. If ammonia fuel can be refueled at the berthing port, ammonia fuel is refueled and it sails to the next berthing port by burning ammonia fuel; if ammonia fuel cannot be refueled, marine fuel is refueled. Ammonia fuel is burned first during navigation. After the ammonia fuel is exhausted, marine fuel is burned to sail to the next berthing port.

[0052] After the ship arrives at the next berthing port, it is judged according to whether the berthing port is the destination port. If the berthing port is the destination port, this shipping route ends; if the berthing port is not the destination port, it continues to sail to the next berthing port according to this method to select fuel refueling.

[0053] Whether the ammonia fuel in the multi-functional tank 2 and the marine fuel in the fuel oil tank 9 can reach the next port can be obtained according to the ratio of the total heat released by the existing ammonia fuel and marine fuel on the ship at present (M 氨 q 氨 +M 油 q 油 ) to the energy required under the average daily operating power of the ship 24P / η, so as to obtain the relationship formula with the number of sailing days, as shown in formula (Ⅰ).

[0054]

[0055] M 氨 is the mass of ammonia fuel in the multifunctional tank 2, in kg;

[0056] q 氨 is the calorific value of ammonia fuel, 18.6 MJ / kg;

[0057] M 油 is the mass of marine fuel in the fuel oil tank 9, in kg;

[0058] q 油 is the calorific value of marine fuel, 42 MJ / kg;

[0059] P is the average operating power of the ship's main engine, in W;

[0060] η is the efficiency of the diesel engine, usually 45% - 50%;

[0061] T is the number of days of the ship's voyage;

[0062] μ is a safety factor, usually taken as 1.2 - 1.5, the smaller the value for longer routes and the larger the value for shorter routes.

[0063] During the ship's voyage, the route is not fixed and there are many berthing ports in the middle. In this embodiment, taking Ports A1, A2, and A3 as examples, the method of the present invention will be illustrated.

[0064] Embodiment 1: Assume that Port A1 is the departure port and Port A2 is the destination port. The ship departs from Port A1 and calculates through formula (Ⅰ) whether the existing ammonia fuel in the multifunctional tank 2 and the existing marine fuel in the fuel oil tank 9 can reach Port A2 and makes a judgment. If it can reach Port A2, a judgment is made according to whether the multifunctional tank 2 is fully filled with ammonia fuel. If it is fully filled with ammonia fuel, first use ammonia fuel and then burn marine fuel to sail to Port A2; if it is not fully filled with ammonia fuel, a judgment is made according to whether ammonia fuel can be refueled at Port A1. If ammonia fuel can be refueled at Port A1, fill the unfilled multifunctional tank 2 with ammonia fuel, then first use ammonia fuel and then burn marine fuel to sail to Port A2; if ammonia fuel cannot be refueled at Port A1, first use ammonia fuel and then burn marine fuel to sail to Port A2.

[0065] If it is calculated through formula (Ⅰ) that the existing ammonia fuel in the multifunctional tank 2 and the existing marine fuel in the fuel oil tank 9 cannot reach Port A2, a judgment is made according to whether ammonia fuel can be refueled at Port A1. If it can be refueled with ammonia fuel, fill the unfilled multifunctional tank 2 with ammonia fuel, then first use ammonia fuel and then burn marine fuel to sail to Port A2; if ammonia fuel cannot be refueled at Port A1, refuel with marine fuel at Port A1, first use ammonia fuel and then burn marine fuel to sail to Port A2.

[0066] If marine fuel is burned during navigation, after the ship arrives at Port A2, the CO2 stored in the multi-functional tank 2 is discharged at Port A2, freeing up the multi-functional tank 2 for storing ammonia fuel or CO2.

[0067] After the ship arrives at Port A2, a judgment is made based on whether Port A2 is the destination port. If Port A2 is the destination port, then this shipping route ends; if Port A2 is not the destination port, then at Port A2, continue sailing according to this method to the next berthing port to select fuel filling. Since it is assumed that Port A2 is the destination port, then this shipping route ends.

[0068] Example 2: Assume that Port A1 is the departure port, Port A2 is the intermediate berthing port, and Port A3 is the destination port. The ship departs from Port A1 and calculates through formula (Ⅰ) whether the existing ammonia fuel in the multi-functional tank 2 and the existing marine fuel in the fuel tank 9 can reach Port A2 and makes a judgment. If it can reach Port A2, a judgment is made based on whether the multi-functional tank 2 is fully filled with ammonia fuel. If the multi-functional tank 2 is fully filled with ammonia fuel, then first burn ammonia fuel and then burn marine fuel to sail to Port A2; if the multi-functional tank 2 is not fully filled with ammonia fuel, then a judgment is made based on whether Port A1 can refuel ammonia. If Port A1 can refuel ammonia, then fill the unfilled multi-functional tank 2 with ammonia fuel, then first burn ammonia fuel and then burn marine fuel to sail to Port A2; if Port A1 cannot refuel ammonia, then first burn ammonia fuel and then burn marine fuel to sail to Port A2.

[0069] If it is calculated through formula (Ⅰ) that the existing ammonia fuel in the multi-functional tank 2 and the existing marine fuel in the fuel tank 9 cannot reach Port A2, then a judgment is made based on whether Port A1 can refuel ammonia. If it can refuel ammonia, then fill the unfilled multi-functional tank 2 with ammonia fuel, then first burn ammonia fuel and then burn marine fuel to sail to Port A2; if Port A1 cannot refuel ammonia, then refuel marine fuel at Port A1, first burn ammonia fuel and then burn marine fuel to sail to Port A2.

[0070] If marine fuel is burned during navigation, after the ship arrives at Port A2, the CO2 stored in the multi-functional tank 2 is discharged at Port A2, freeing up the multi-functional tank 2 for storing ammonia fuel or CO2.

[0071] After the ship arrives at Port A2, a judgment is made based on whether Port A2 is the destination port. If Port A2 is the destination port, then this shipping route ends; if Port A2 is not the destination port, then at Port A2, continue sailing according to this method to Port A3 to select fuel filling. Since it is assumed that Port A2 is an intermediate berthing port and not the destination port, then continue sailing according to this method to Port A3 to select fuel filling.

[0072] The ship now departs from Port A2 and calculates through formula (Ⅰ) whether the existing ammonia fuel in the multi-functional tank 2 and the existing marine fuel in the fuel oil tank 9 can reach Port A3 and makes a judgment. If it can reach Port A3, it makes a judgment based on whether the multi-functional tank 2 is fully filled with ammonia fuel. If it is fully filled with ammonia fuel, it first burns ammonia fuel and then burns marine fuel to sail to Port A3; if it is not fully filled with ammonia fuel, it makes a judgment based on whether ammonia fuel can be refueled at Port A2. If ammonia fuel can be refueled at Port A2, it fills the unfilled multi-functional tank 2 with ammonia fuel, then first burns ammonia fuel and then burns marine fuel to sail to Port A3; if ammonia fuel cannot be refueled at Port A2, it first burns ammonia fuel and then burns marine fuel to sail to Port A3.

[0073] If it is calculated through formula (Ⅰ) that the existing ammonia fuel in the multi-functional tank 2 and the existing marine fuel in the fuel oil tank 9 cannot reach Port A3, it makes a judgment based on whether ammonia fuel can be refueled at Port A2. If it can be refueled with ammonia fuel, it fills the unfilled multi-functional tank 2 with ammonia fuel, then first burns ammonia fuel and then burns marine fuel to sail to Port A3; if ammonia fuel cannot be refueled at Port A2, it refuels with marine fuel at Port A2, first burns ammonia fuel and then burns marine fuel to sail to Port A3.

[0074] If marine fuel is burned during navigation and the ship arrives at Port A3, the CO2 stored in the multi-functional tank 2 is discharged at Port A3 to vacate the multi-functional tank 2 for storing ammonia fuel or CO2.

[0075] After the ship arrives at Port A3, it makes a judgment based on whether Port A3 is the destination port. If Port A3 is the destination port, this shipping route ends; if Port A3 is not the destination port, it continues to sail at Port A3 according to this method to the next berthing port to select fuel refueling. Since it is assumed that Port A3 is the destination port, this shipping route ends.

[0076] Since bulk carriers usually have long shipping routes and the berthing ports during navigation are not fixed, there may be n berthing ports in the middle. By analogy with the methods of Embodiment 1 and Embodiment 2, it continues to sail to the next berthing port to select fuel refueling.

[0077] The current ammonia fuel engine can burn marine fuel alone or burn ammonia fuel (with marine fuel as the pilot fuel). The present invention only needs to equip a set of ammonia fuel engines on the ship, so there will be no additional equipment costs.

[0078] As a carbon-free fuel, when the ship burns ammonia fuel during navigation, it does not need to capture CO2. However, when the ship burns marine fuel, a large amount of tail gas will be generated, and at this time, it is necessary to capture and liquefy the CO2 in the tail gas.

[0079] In this embodiment, during the process that ammonia fuel and marine fuel can reach the next berthing port, if only burning ammonia fuel can reach the next berthing port, then only burn ammonia fuel; if only burning ammonia fuel cannot reach the next berthing port, then first burn ammonia fuel and then burn marine fuel to reach the next berthing port.

[0080] Since bulk carriers usually have long voyages and their berthing ports are not fixed, developed ports have the conditions for ammonia fuel refueling, while underdeveloped ports do not. The system and method of the present invention can refuel ammonia fuel at the berthing ports with ammonia fuel refueling conditions according to whether the current berthing port of the bulk carrier has the conditions for ammonia fuel refueling, and preferentially burn ammonia fuel during navigation; flexibly choose to refuel marine fuel at berthing ports without refueling conditions, and adopt the marine fuel + carbon capture mode during navigation. This can not only solve the current dilemma of difficult ammonia fuel refueling for ammonia fuel bulk carriers, promote the large-scale application of ammonia fuel on bulk carriers, but also, as more bulk carriers burn ammonia fuel, encourage more ports to build ammonia fuel refueling stations. At the same time, the system and method of the present invention can almost achieve "zero-carbon" emissions when burning ammonia fuel, and capture CO2 when burning marine fuel. Through this ingenious combination method, it can not only solve the current dilemma of difficult ammonia fuel refueling for ammonia fuel bulk carriers, promote the large-scale application of ammonia fuel on bulk carriers, but also meet the stringent requirements of IMO for exhaust emissions.

[0081] Due to the low calorific value of ammonia fuel, ships need more space to store ammonia fuel. At the same time, ammonia fuel is usually stored in liquid form (liquid ammonia) under low-temperature (-33°C) conditions, and ammonia fuel has characteristics such as flammable, explosive, and corrosive, so the storage requirements for ammonia fuel on ships are relatively high. In addition, the amount of CO2 emitted by ships burning marine fuel every day is very large, requiring a large amount of space to store CO2, and the storage conditions for CO2 are relatively high. Usually, it is stored in a type C tank 1 in a semi-cooled and semi-pressurized manner (with a working pressure between 0.7 MPa and 1.5 MPa and a working temperature between -50°C and -20°C). There are many empty holds on bulk carriers. The present invention utilizes the similar storage conditions of ammonia fuel and liquid CO2 and the existing empty holds 10 on bulk carriers, and uses a multi-functional tank 2 to store ammonia fuel or captured CO2, providing a reasonable storage space for ammonia fuel and liquid CO2. Through the ingenious combination of the multi-functional tank 2 and the empty holds 10, the common problems of large space requirements and high requirements for the storage of ammonia fuel and CO2 are solved simultaneously.

[0082] The above are only the preferred embodiments of the present invention, but the implementation is not limited by the above embodiments. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. An ammonia fuel-powered bulk carrier fuel and CO2 storage system, characterized in that: The system includes a C-type tank (1), a multi-functional tank (2), an ammonia pump (3), a fuel pump (4), an ammonia valve (5), a fuel valve (6), a CO2 valve (7), a three-way valve (8), a fuel tank (9), an empty tank (10), a main engine, a carbon capture unit, and a CO2 liquefaction unit. The multi-functional tank (2) is formed by arranging three C-type tanks (1) in sequence from top to bottom. Each C-type tank (1) is connected into a whole through pipelines in the middle. The multi-functional tank (2) is placed in the empty tank (10) of the ship, and the empty tank (10) is located on both sides of the ship's side. The ammonia pump (3) in the multi-functional tank (2) is connected to the ammonia valve (5), the main engine, and the three-way valve (8) through pipelines in sequence, and the generated tail gas is discharged to the atmosphere for treatment. The fuel pump (4) in the fuel tank (9) is connected to the fuel valve (6), the main engine, the three-way valve (8), the carbon capture unit, the CO2 liquefaction unit, the CO2 valve (7), and the multi-functional tank (2) through pipelines in sequence.

2. The fuel and CO2 storage system for an ammonia-fueled bulk carrier according to claim 1, characterized in that: The C-type tank (1) is a storage tank with a heat-insulating layer, corrosion resistance, and a certain pressure-bearing capacity. The shape of the C-type tank (1) is cylindrical in the middle and hemispherical at both ends.

3. The fuel and CO2 storage system for an ammonia fuel-powered bulk carrier according to claim 1, characterized in that: The multi-functional tank (2) can store both ammonia fuel and liquid CO2.

4. A fuel and CO2 storage system for an ammonia-fueled bulk carrier according to claim 1, characterized in that: The ammonia pump (3) is placed at the bottom inside the lowermost C-type tank (1) of the multi-functional tank (2); the fuel pump (4) is placed at the bottom inside the fuel tank (9).

5. A fuel and CO2 storage method for an ammonia fuel-powered bulk carrier according to claim 1, characterized in that: First, before the ship sails, calculate whether the existing ammonia fuel in the ship's multi-functional tank (2) and the existing marine fuel in the fuel tank (9) can reach the next berthing port at this berthing port and make a judgment. When it can reach the next berthing port, then make a judgment according to whether the multi-functional tank (2) is fully filled with ammonia fuel. When it is fully filled with ammonia fuel, sail to the next berthing port using ammonia fuel. When it is not fully filled with ammonia fuel, then make a judgment according to whether ammonia fuel can be refueled at this berthing port. When ammonia fuel can be refueled, fill the unfilled multi-functional tank (2) with ammonia fuel and sail to the next berthing port using ammonia fuel. When ammonia fuel cannot be refueled, give priority to using ammonia fuel, then use marine fuel to sail to the next berthing port, and store the captured CO2 in the empty multi-functional tank (2). When the existing ammonia fuel and marine fuel of the ship cannot reach the next berthing port, then make a judgment according to whether ammonia fuel can be refueled at this port. When ammonia fuel can be refueled at this port, then refuel with ammonia fuel and sail to the next berthing port using ammonia fuel. When ammonia fuel cannot be refueled, then marine fuel needs to be refueled. First, use ammonia fuel during sailing. After the ammonia fuel is exhausted, then use marine fuel to sail to the next berthing port, and store the captured CO2 in the empty multi-functional tank (2). Finally, after the ship arrives at the next berthing port, make a judgment according to whether the berthing port is the destination port. When the berthing port is the destination port, then this shipping route ends; when the berthing port is not the destination port, then continue sailing to the next berthing port according to this method to select fuel refueling.

6. A method for storing fuel and CO2 in an ammonia fuel-powered bulk carrier according to claim 5, characterized in that: Whether the ammonia fuel in the multi-functional tank (2) and the marine fuel in the fuel oil tank (9) can reach the next port can be determined by the ratio of the total heat released by the existing ammonia fuel and marine fuel on the ship at present (M 氨 q 氨 +M 油 q 油 ) to the energy required at the average daily operating power of the ship, 24P / η, so as to obtain the relationship with the number of sailing days, M 氨 is the mass of the ammonia fuel in the multi-functional tank (2), q 氨 is the calorific value of the ammonia fuel, M 油 is the mass of the marine fuel in the fuel oil tank (9), q 油 is the calorific value of the marine fuel, P is the average operating power of the ship's main engine, η is the efficiency of the diesel engine, usually 45% - 50%, T is the number of days of the ship's voyage, μ is the safety factor, and the value range is 1.2 - 1.5.

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