Liquid ammonia filling method, ammonia filling storage system and supply recovery device

Abstract

To provide an ammonia filling method capable of operating without any trouble even when, for example, a fuel tank with a pressure resistance of 0.3 MPa or less is used, in a case of filling, for example, a fuel tank used at room temperature with liquid ammonia.SOLUTION: A liquid ammonia filling method executes, when filling a second fuel tank T2 with liquid ammonia al from a liquid fuel supply facility S, a first step in which the second fuel tank T2 is cooled by releasing ammonia gas ag from the second fuel tank T2 through an established recovery path RR to make a temperature lower than a cooling control stop temperature, which is a temperature at which ammonia is kept in a liquid phase at a pressure resistance of the second fuel tank, and a second step for continuing filling following the first step and completing the filling.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a method for filling a fuel tank of an automobile that uses ammonia as fuel with liquid ammonia, for example, and to an ammonia filling and storage system to be constructed when filling the fuel tank with liquid ammonia from a fuel station (corresponding to the liquid fuel equipment of the present invention) that stores ammonia in the form of liquid ammonia and storing the ammonia in the fuel tank. [Background technology]

[0002] A technology that directly obtains electricity by using ammonia as fuel has been attracting attention (Patent Documents 1 and 2). In this technology, hydrogen is obtained from ammonia, electricity is generated in a fuel cell, and the electricity is used. A well-known example of this type of application is a fuel cell vehicle that uses electricity supplied by a fuel cell. When ammonia is used as fuel, CO 2 The advantage is that no carbon dioxide is generated and no carbon deposits are formed on the electrodes of the fuel cell.

[0003] On the other hand, with regard to the storage of ammonia, it has also been proposed to use an ammonia storage material that occludes ammonia and becomes liquid (Patent Document 3). By using this type of ammonia storage material, ammonia can be stored in a liquid state in a tank with a relatively small capacity.

[0004] As a form of use for the ammonia storage material, the inventors have proposed a system in which ammonia is stored and supplied in an appropriate state by varying the ratio of ammonia storage material to liquid ammonia and adjusting the boiling points of these two liquids (Patent Document 4). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2011-204416 A [Patent Document 2] JP 2011-204418 A [Patent Document 3] JP 2014-043359 A [Patent Document 4] Patent Publication No. 2021-022501 Summary of the Invention [Problem to be solved by the invention]

[0006] The technologies developed so far have aimed to stably store liquid ammonia when the temperature of the fuel tank is at room temperature (around 23°C, which can vary from around -10°C to around 35°C). On the other hand, it is preferable that the pressure resistance of the fuel tank is 0.3 MPa or less, which is outside the scope of the High Pressure Gas Safety Act. This pressure resistance of 0.3 MPa is the so-called absolute pressure, which is 0.2 MPa in gauge pressure. By making the pressure resistance of the fuel tank outside the scope of the High Pressure Gas Safety Act in this way, the options for the shape of the fuel tank can be improved significantly.

[0007] However, when ammonia is the target, it is assumed that liquid ammonia is stored at a very low temperature (for example, about -40°C) in a fuel station and supplied in this state to, for example, an on-board fuel tank. Here, if liquid ammonia is supplied from the fuel station to a fuel tank at room temperature to fill it, the liquid ammonia will bump, causing the internal pressure in the fuel tank to rise rapidly. For this reason, fuel tanks that comply with the High Pressure Gas Safety Act have been used as fuel tanks. For example, tanks for transporting ammonia that are provided on tank trucks fall into this category. Therefore, it has been thought that so-called high-pressure containers would be necessary even for automobiles that use ammonia as fuel, for example.

[0008] Furthermore, in the summer, the temperature of a fuel tank not equipped with a cooling device rises to about 35° C. In this situation, no definite technology has yet been established as to how to fill a fuel tank containing the above-mentioned ammonia storage material with liquid ammonia and store the ammonia (in this storage state, the ammonia is stored as a liquid occluded in the ammonia storage material).

[0009] An object of the present invention is to provide an ammonia filling method which allows for unhindered filling and storage of ammonia, for example, when filling a fuel tank used at room temperature with liquid ammonia, even if a fuel tank with a pressure resistance of 0.3 MPa is used during the filling process and in the storage state after filling, and further to provide an ammonia filling storage system for carrying out this method. [Means for solving the problem]

[0010] The first characteristic configuration of the present invention is as follows: A liquid fuel supply facility including a first fuel tank for cooling and storing liquid ammonia and a supply device for supplying liquid ammonia from the first fuel tank; A method for filling liquid ammonia in an ammonia filling and storage system comprising a tank for storing liquid ammonia in a state in which an ammonia occlusion material that occludes ammonia and becomes liquid is mixed, the second fuel tank having an intake port for receiving liquid ammonia from the liquid fuel supply facility and an outlet port for discharging ammonia, a supply line for supplying liquid ammonia from the liquid fuel supply facility to the second fuel tank; establishing a discharge path for discharging ammonia from the second fuel tank; When liquid ammonia is filled into the second fuel tank from the liquid fuel supply facility, The present invention is characterized in that a first step is carried out in which the second fuel tank is cooled by releasing ammonia gas from the second fuel tank through the established release path, and the temperature inside the second fuel tank is set to a cooling control stop temperature or lower, which is a temperature at which ammonia maintains a liquid phase at the withstand pressure of the second fuel tank, and a second step is carried out in which, following the first step, the filling is continued and the filling is completed.

[0011] The second characteristic configuration of the present invention is as follows: A liquid fuel supply facility including a first fuel tank for cooling and storing liquid ammonia and a supply device for supplying liquid ammonia from the first fuel tank; A method for filling liquid ammonia in an ammonia filling and storage system comprising a tank for storing liquid ammonia in a state in which an ammonia occlusion material that occludes ammonia and becomes liquid is mixed, the second fuel tank having an intake port for receiving liquid ammonia from the liquid fuel supply facility and an outlet port for discharging ammonia, a supply line for supplying liquid ammonia from the liquid fuel supply facility to the second fuel tank; establishing a recovery path for recovering ammonia from the second fuel tank to the liquid fuel supply facility; When liquid ammonia is filled into the second fuel tank from the liquid fuel supply facility, The present invention is characterized in that a first step is carried out in which the second fuel tank is cooled by releasing ammonia gas from the second fuel tank through the established recovery path, and the temperature inside the second fuel tank is set to a cooling control stop temperature or lower, which is a temperature at which ammonia maintains a liquid phase at the withstand pressure of the second fuel tank, and a second step is carried out in which, following the first step, the filling is continued and the filling is completed.

[0012] In the liquid ammonia filling method according to the present invention, in both the first characteristic configuration and the second characteristic configuration, when filling the second fuel tank with liquid ammonia from the liquid fuel supply facility, a first step is performed in which the second fuel tank is cooled by releasing ammonia gas from the second fuel tank to make the temperature inside the second fuel tank equal to or lower than a cooling control stop temperature, which is a temperature at which ammonia maintains a liquid phase at the withstand pressure of the second fuel tank, and a second step is performed in which the filling is continued following the first step to complete the filling. The only difference between the two is which path (release path or recovery path) the ammonia gas is released through. Therefore, the following will explain the actions and effects of the common points.

[0013] As described above, when ammonia gas is released from the second fuel tank, it becomes possible to recover latent heat accompanying the vaporization of ammonia, thereby cooling the inside of the second fuel tank. Here, in the present invention, the temperature of the second fuel tank is set to a cooling control stop temperature or lower (first step). Then, in the second step following the first step, the ammonia in the second fuel tank maintains its liquid state by continuing to be at or below this temperature. As a result, in this second step, the liquid ammonia being supplied is in a liquid state at an extremely low temperature, and the ammonia already received in the second fuel tank also maintains its liquid state, so that liquid-liquid mixing can be stably performed to complete the filling.

[0014] Furthermore, as will be described later with reference to Fig. 3, the completion of the absorption of ammonia into the ammonia absorption material is delayed with respect to the timing of completion of filling the second fuel tank with liquid ammonia, but the temperature of the second fuel tank can be substantially kept below the cooling control stop temperature until the absorption is completed. As a result, absorption can be completed under a pressure below the withstand pressure of the second fuel tank.

[0015] In this manner, by completing the filling of liquid ammonia from the liquid fuel supply facility and storing ammonia in the second fuel tank with the ammonia occluded in the ammonia occlusion material, even if the tank temperature becomes room temperature, the internal tank pressure will not exceed the withstand pressure of the tank, and the tank can function satisfactorily as an ammonia storage tank.

[0016] In the above explanation, the expressions "filling", "occlusion" and "storage" are used, but in the present invention, these are explained as follows. Filling; supplying liquid ammonia from a liquid fuel supply system to the second fuel tank. It will be accepted at the second fuel tank side. Absorption: When ammonia comes into contact with an ammonia absorption material, the two become a single liquid. Storage: Liquid ammonia is stored in the second fuel tank. In this state, the ammonia stored in the ammonia storage material and liquid ammonia as a single substance may coexist. This also includes the case where ammonia is discharged from the second fuel tank and consumed, and further ammonia is stored in the ammonia storage material.

[0017] The configuration of the ammonia filling and storage system for implementing the liquid ammonia filling method of the first characteristic configuration can be as follows, as described in a sixth characteristic configuration. A liquid fuel supply facility including a first fuel tank for cooling and storing liquid ammonia and a supply device for supplying liquid ammonia from the first fuel tank; An ammonia filling and storage system comprising: a tank for storing liquid ammonia in a state in which an ammonia occlusion material that occludes ammonia and becomes liquid is mixed, the second fuel tank having an intake port for receiving liquid ammonia from the liquid fuel supply facility and an outlet port for discharging ammonia, a supply line for supplying liquid ammonia from the liquid fuel supply facility to the second fuel tank; a discharge path for discharging ammonia from the second fuel tank, When liquid ammonia is filled into the second fuel tank from the liquid fuel supply facility, An ammonia filling and storage system comprising: a cooling control means for executing a first step of cooling the second fuel tank by releasing ammonia gas from the second fuel tank through the established release path, and making the temperature inside the second fuel tank equal to or lower than a cooling control stop temperature, which is a temperature at which ammonia remains in a liquid phase at the withstand pressure of the second fuel tank; and a filling control means for executing a second step of continuing filling following the first step to complete the filling.

[0018] The configuration of the ammonia filling and storage system for implementing the liquid ammonia filling method of the second characteristic configuration can be as follows, as described in the seventh characteristic configuration. A liquid fuel supply facility including a first fuel tank for cooling and storing liquid ammonia and a supply device for supplying liquid ammonia from the first fuel tank; An ammonia filling and storage system comprising a tank for storing liquid ammonia in a state in which an ammonia occlusion material that occludes ammonia and becomes liquid is mixed, the second fuel tank having an inlet for receiving liquid ammonia from the liquid fuel supply facility and an outlet for discharging ammonia, a supply line for supplying liquid ammonia from the liquid fuel supply facility to the second fuel tank; a recovery path for recovering ammonia from the second fuel tank to the liquid fuel supply facility, When liquid ammonia is filled into the second fuel tank from the liquid fuel supply facility, An ammonia filling and storage system comprising: a cooling control means for executing a first step of cooling the second fuel tank by releasing ammonia gas from the second fuel tank through the established recovery path, and making the temperature inside the second fuel tank equal to or lower than a cooling control stop temperature, which is a temperature at which ammonia remains in a liquid phase at the withstand pressure of the second fuel tank; and a filling control means for executing a second step of continuing filling following the first step to complete the filling.

[0019] The third characteristic configuration of the present invention is as follows: When filling the second fuel tank with liquid ammonia through the supply passage, the pressure in the second fuel tank is adjusted to be equal to or lower than a withstand pressure set for the second fuel tank.

[0020] According to this configuration, by releasing the ammonia gas that is excessively generated accompanying the evaporation of ammonia (which corresponds to latent heat recovery in the present invention) from inside the second fuel tank, the evaporation of liquid ammonia is promoted, and the temperature inside the second fuel tank can be lowered (cooled) to an appropriate temperature in the present invention.

[0021] The configuration of the ammonia filling and storage system for implementing the liquid ammonia filling method of the third characteristic configuration can be as follows, as described in an eighth characteristic configuration. The ammonia filling and storage system according to claim 1, wherein the cooling control means is configured to adjust the pressure in the second fuel tank to a pressure resistance set for the second fuel tank or lower when the second fuel tank is filled with liquid ammonia via the supply path.

[0022] In this configuration, the cooling control means can be constructed with a simple valve mechanism.

[0023] A fourth characteristic configuration of the present invention is that when liquid ammonia is charged through the supply path, in the first step, ammonia gas is sucked and recovered through the recovery path into the liquid fuel supply facility.

[0024] According to this configuration, by lowering the internal pressure in the second fuel tank, the vaporization of at least the liquid ammonia is promoted, and as a result, the temperature in the second fuel tank can be quickly lowered to the cooling control stop temperature. In this suction, for example, the suction force of a supply device (for example, a discharge pump for discharging liquid ammonia) provided on the liquid fuel supply facility side can be used for this suction.

[0025] The configuration of the ammonia filling and storage system for implementing the liquid ammonia filling method of the fourth characteristic configuration can be as follows, as described in a ninth characteristic configuration. The ammonia filling and storage system, wherein the cooling control means is a suction and recovery means that, in the first step, when liquid ammonia is filled through the supply path, sucks and recovers ammonia gas through the recovery path into the liquid fuel supply facility.

[0026] A fifth characteristic configuration of the present invention is that when liquid ammonia is charged through the supply path, ammonia gas is released through the recovery path prior to charging of the liquid ammonia through the supply path.

[0027] As explained above, when the second fuel tank starts to be filled with liquid ammonia, the second fuel tank is at room temperature. On the other hand, the "cooling control stop temperature" unique to the present invention is below room temperature, and it is preferable to cool the second fuel tank to this temperature as quickly as possible. Normally, the fuel tank is not in a state in which the ammonia has been completely consumed, and there are cases in which the ammonia-absorbing material in a liquid state remains in the fuel tank. Therefore, prior to filling the second fuel tank with liquid ammonia, for example, the pressure in the second fuel tank is reduced to separate the ammonia from the storage material and release the ammonia gas from the second fuel tank, thereby reducing the degree of bumping of the supplied liquid ammonia while at the same time allowing the temperature in the second fuel tank to reach the cooling control stop temperature quickly.

[0028] The configuration of the ammonia filling and storage system for implementing the liquid ammonia filling method according to the fifth characteristic configuration can be as follows, as described in a tenth characteristic configuration. The ammonia filling and storage system, wherein the cooling control means is a recovery and supply timing adjustment means for prioritizing the release of ammonia gas via the recovery line when filling liquid ammonia via the supply line.

[0029] In addition, the ammonia filling and storage system configured with the supply path and recovery path described above is an eleventh characteristic configuration of the present invention. a supply path establishing means for receiving liquid ammonia from the liquid fuel supply facility and supplying the liquid ammonia to the receiving port of the second fuel tank; and a recovery path establishing means for receiving ammonia from the discharge port of the second fuel tank and recovering it in the liquid fuel supply facility. [Brief description of the drawings]

[0030] [Figure 1] FIG. 1 is a schematic diagram showing one mode of use of the ammonia charging and storage system according to the present invention. [Diagram 2] FIG. 1 is a schematic diagram showing a specific configuration example of an ammonia charging and storage system according to the present invention. [Diagram 3] Diagram showing ammonia charging, storage and consumption behavior [Figure 4] Time chart for ammonia charging, storage and consumption [Diagram 5] Diagram showing the vapor line of ammonia [Figure 6] Time chart for charging, storing and consuming ammonia with a different configuration DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. As shown in Figs. 1 and 2, the present invention is established between a liquid fuel supply facility S having a first fuel tank T1, which is a supply side of liquid ammonia a1, and a second fuel tank T2 which receives the supply of liquid ammonia a1 from the first fuel tank T1. First, as an example, the configuration of an automobile car using ammonia as fuel f will be briefly described.

[0032] As shown in FIG. 1, the automobile car is configured to include at least a second fuel tank T2 and a fuel cell device FC. Ammonia (NH 3The electricity generated by the fuel cell FC is sent to a power conditioner (not shown), a storage battery (not shown), etc., where it is converted and stored as required, and then sent to an electric motor M provided downstream for use.

[0033] [Ammonia filling and storage system] FIG. 2 is a schematic diagram showing the main configuration of the ammonia charging and storage system 100. As shown in FIG. The liquid fuel supply facility S is configured to include a first fuel tank T1 that cools and stores liquid ammonia a1, and a discharge pump P1 as a supply device that supplies liquid ammonia a1 from the first fuel tank T1. Therefore, the liquid fuel supply facility S is provided with a cooling device RF that cools the first fuel tank T1 or the liquid ammonia a1 stored in this tank. Furthermore, in this example, the liquid fuel supply equipment S is provided with a reserve tank Ta for receiving ammonia gas ag, and is configured to be able to receive ammonia gas ag recovered from the second fuel tank T2, as described later. This received ammonia gas ag is also liquefied appropriately and returned to the first fuel tank T1. Of course, a structure may be adopted in which the ammonia gas ag recovered from the second fuel tank T2 is returned directly to the gas phase portion of the first fuel tank T1, without providing a reserve tank Ta. In this embodiment, an example is described in which the ammonia gas ag is returned to the liquid fuel supply equipment S side, but if the device configuration allows, it may also be returned to the automobile car side. Separately Alternatively, the wastewater may be returned to a recovery tank (not shown).

[0034] In the first fuel tank T1, the liquid ammonia a1 is held at a temperature of, for example, −50 to −20° C. and a pressure of 0.1 to 0.3 MPa. The discharge pump P1 is used to discharge the liquid ammonia a1, and a separate pump (not shown) may be provided to receive the ammonia gas ag, or the suction function of the discharge pump P1 may be used.

[0035] The second fuel tank T2 is a tank for storing liquid ammonia a1 in a state in which the ammonia occlusion material aA is mixed, and is configured to include an inlet in for receiving liquid ammonia a1 from the liquid fuel supply facility S, and an outlet out for discharging at least ammonia gas ag. This outlet out is configured to be recoverable to the liquid fuel supply facility S side, and is configured to be capable of supplying ammonia to an external use via a discharge path F0 with pressure adjustment by a boost pump Pu, a pressure adjustment valve CV, etc., in order to provide the ammonia for a predetermined external use (such as the above-mentioned use as fuel or a reducing agent).

[0036] The ammonia storage material aA is a material that absorbs ammonia and becomes liquid, and can be one or more selected from alkali metal borohydrides, alkaline earth metal borohydrides, and ammonium halide compounds. The amount of ammonia storage material aA to be mixed is determined based on the amount of ammonia to be stored in the second fuel tank T2 and the capacity of the second fuel tank T2. Incidentally, no ammonia storage material is mixed in the first fuel tank T1.

[0037] Although it is conceivable that the second fuel tank T2 is provided with a cooling device for cooling, the present embodiment does not include a cooling device. In this respect, in the present invention, since temperature management of the second fuel tank T2 is an important element, a heat insulating layer HS is provided around the tank T2 to ensure sufficient heat insulation. Normally, ammonia is stored in the second fuel tank T2 at room temperature and at a pressure equal to or lower than the withstand pressure of the second fuel tank T2 (0.3 MPa or less). When ammonia is discharged from the second fuel tank T2, the tank internal pressure acts, and when liquid ammonia a1 is received from the liquid fuel supply facility S, the pump Pa on the facility S side works.

[0038] As shown in FIG. 2, the ammonia filling and storage system 100 is further configured to be capable of establishing a supply path FR that supplies liquid ammonia a1 from the liquid fuel supply facility S to the second fuel tank T2, and a recovery path RR that recovers the ammonia from the second fuel tank T2 to the liquid fuel supply facility S. Therefore, the liquid fuel supply facility S and the second fuel tank T2 become an integrated system 100 by the supply path FR and the recovery path RR.

[0039] In the present invention, the equipment that constitutes the ammonia filling and storage system 100 is called the "supply and recovery equipment", and this equipment includes a supply path establishing means (specifically, a connector that connects the discharge port of the discharge pump P1 and the receiving port in) that receives liquid ammonia a1 from the liquid fuel supply facility S and supplies it to the receiving port in of the second fuel tank T2, The second fuel tank T2 is provided with a recovery path establishing means (specifically, a connector that connects the discharge port out and the inlet of the valve mechanism V that functions as the cooling control means C1 in the present invention) that receives ammonia from the discharge port out of the second fuel tank T2 and recovers it in the liquid fuel supply facility S.

[0040] In relation to its mode of use, the ammonia filling and storage system 100 is equipped with a cooling control means C1 which executes a first step of cooling the second fuel tank T2 by releasing ammonia gas ag from the second fuel tank T2 via an established recovery path RR when liquid ammonia a1 is filled into the second fuel tank T2 from the liquid fuel supply facility S, and a filling control means C2 which executes a second step of continuing the filling following the first step and completing the filling.

[0041] In the example shown in FIG. 2, the cooling by the cooling control means C1 controls the temperature inside the second fuel tank T2 to a temperature equal to or lower than a cooling control stop temperature that is preset for the liquid ammonia a1 mixed with the ammonia occlusion material aA.

[0042] As a specific configuration of the cooling control means C1, the cooling control means C1 is configured with a valve mechanism V that adjusts the pressure inside the second fuel tank T2 to a pressure resistance set for the second fuel tank T2 or less when the liquid ammonia a1 is filled through the supply path FR. This valve mechanism V is a so-called release valve, and is a valve that releases the internal pressure when the pressure inside the second fuel tank T2 rises above 0.3 MPa. As explained above, when the pressure resistance set for the second fuel tank T2 is 0.3 MPa, the cooling control stop temperature is about -10°C, as can be seen from Fig. 5, which shows the vapor pressure curve of ammonia.

[0043] The filling control means C2 is constructed as a control device for the discharge pump P1 that continues filling with liquid ammonia al (continues filling by operating the discharge pump P1) even after the cooling by the cooling control means C1 is completed, and completes the filling. Basically, it is a means for detecting and controlling the completion of filling by detecting the amount of liquid ammonia a1 filled in the second fuel tank T2. Such a means can be constructed appropriately as hardware and software according to the purpose.

[0044] [Charging, absorbing and consuming ammonia] One object of the present invention is to fill the second fuel tank T2 with liquid ammonia a1 from the liquid fuel supply facility S, and in the present invention, ammonia storage material aA is mixed in each phase of filling, storing, and consuming ammonia, thereby realizing stable operation. In this regard, the behavior of ammonia in the second fuel tank T2 will be described with reference to Figs. 3 and 4.

[0045] The cycle that ammonia goes through is shown in the center of Figure 3, and specific states P1 to P6 are shown in boxes. In the ammonia cycle, the vertical axis is the ammonia pressure (MPa; absolute pressure) in the second fuel tank T2, and the horizontal axis is the amount of ammonia stored in the second fuel tank T2. The horizontal axis indicates the amount of ammonia stored, increasing toward the right on the figure.

[0046] The ammonia in the second fuel tank T2 changes to states P1 to P6, and states P1 to P5 are states until the filling of liquid ammonia a1 and the absorption of ammonia by the ammonia absorption material aA are completed, and states P5 to P6 indicate states after the absorption of liquid ammonia a1 is completed, the temperature in the second fuel tank T2 becomes room temperature, and the consumption of ammonia fuel can start in the room temperature state. Therefore, in the figure, P1 to P5 are indicated by shaded thick solid arrows, and P5 to P6 to P1 are indicated by thick solid arrows. Here, in the states of P1 to P5, the ammonia storage material aA, which has absorbed ammonia and is in a liquid state, and unabsorbed liquid ammonia coexist. On the other hand, in the states of P5 to P6 to P1, the absorption is substantially completed and the ammonia storage material aA is in a liquid state.

[0047] The state in which ammonia gas ag is released from the second fuel tank T2, to which the present invention is closely related, is shown by a double dashed arrow above state P2 in the central drawing. Furthermore, the diagram shows the behavior between each state.

[0048] FIG. 4 shows a time chart of the charging, storage and consumption of ammonia corresponding to each of the states P1 to P6.

[0049] Below, each of the states P1 to P6 will be briefly explained. State P1 In the second fuel tank T2, the fuel f has been consumed and the basic ammonia storage material aA remains in the tank. The second fuel tank T2 is at room temperature.

[0050] State P2 After the liquid ammonia a1 starts to be filled into the second fuel tank T2, the pressure inside the tank rises and reaches its withstand pressure. In this state, the temperature of the liquid ammonia a1 on the supply side is, for example, -33°C, and the temperature of the ammonia occlusion material aA is room temperature. As a result, bumping of the liquid ammonia a1 occurs, and the ammonia that exceeds the withstand pressure is recovered to the liquid fuel supply equipment S side via the recovery line RR.

[0051] State P3 By continuing to fill the liquid ammonia a1 beyond state P2, the temperature inside the second fuel tank T2 is continuously cooled and reduced by the latent heat recovery accompanying the vaporization of the liquid ammonia a1. The pressure inside the second fuel tank T2 is maintained at the withstand pressure, and the temperature becomes -10°C or lower. This -10°C is the cooling control stop temperature of the present invention, and is the maximum temperature that must be reached by cooling with latent heat recovery in the present invention. With the configuration of the present invention, cooling control is possible up to any temperature as long as it is below this temperature (-10°C) and above the filling temperature of liquid ammonia al (-33°C). The process up to this state P3 corresponds to the "first step" of the present invention.

[0052] State P4 Since the temperature of the second fuel tank T2 is low until it passes state P3 and reaches state P4, the ammonia remains liquid (does not vaporize). In this state, if the filling of liquid ammonia a1 continues, the temperature inside the tank drops further, and liquid-liquid mixing occurs between the liquid ammonia a1 being filled and the liquid ammonia filled inside the tank, and the temperature becomes uniform. As a result, both the temperature and pressure inside the tank drop. In this state, the absorption of ammonia by the ammonia absorption material aA progresses partially, and the filling can be completed. The process up to this state P4 corresponds to the "second step" of the present invention.

[0053] Condition P5 Even after the filling of the liquid ammonia a1 is completed, the ammonia continues to be absorbed into the ammonia absorption material aA. In states P4 to P5, the pressure inside the tank increases due to the heat received from the outside, but the ammonia absorption by the ammonia absorption material aA continues during this state transition (the amount of ammonia absorbed may increase rapidly under a predetermined pressure), so that the absorption using the ammonia absorption material aA can be performed satisfactorily (see Figs. 2 and 3 of Patent Document 4 described above).

[0054] Condition P6 When the ammonia storage material aA completes storage in accordance with the method of the present invention, the internal pressure of the second fuel tank T2 will not exceed its withstand pressure even if the temperature of the tank rises to room temperature. Thereafter, as fuel is consumed, the state returns from state P6 to state P1.

[0055] The state transition in the second fuel tank T2 is as described above. Below, a method for filling the ammonia with liquid ammonia a1 that is executed until filling is completed after the ammonia filling and storage system 100 of the present invention is constructed will be described.

[0056] [Method of filling liquid ammonia] In the ammonia charging and storage system 100 described above, the following method for charging liquid ammonia a1 is carried out. That is, a method for filling liquid ammonia a1 in an ammonia filling and storage system 100 including a liquid fuel supply facility S including a first fuel tank T1 for cooling and storing liquid ammonia a1 and a supply device P1 for supplying liquid ammonia a1 from the first fuel tank T1, and a second fuel tank T2 which is a tank for storing liquid ammonia a1 in a mixed state with an ammonia occlusion material aA that occludes ammonia and becomes liquid, the second fuel tank T2 having an inlet in for receiving liquid ammonia a1 from the liquid fuel supply facility S and an outlet out for discharging ammonia, A supply line FR for supplying liquid ammonia a1 from the liquid fuel supply facility S to the second fuel tank T2; A recovery path RR is established to recover ammonia from the second fuel tank T2 to the liquid fuel supply facility S, When liquid ammonia a1 is filled from the liquid fuel supply facility S into the second fuel tank T2, The second fuel tank T2 is cooled by releasing the ammonia gas ag from the second fuel tank T2 through the established recovery path RR, and the temperature inside the second fuel tank T2 is set to a cooling control stop temperature or lower, which is a temperature at which ammonia maintains a liquid phase at the withstand pressure of the second fuel tank T2 (first step). Then, the filling is continued following the first step to complete the filling (second step).

[0057] Furthermore, when the liquid ammonia a1 is filled through the supply passage FR, the pressure inside the second fuel tank T2 is adjusted to be equal to or lower than the withstand pressure set for the second fuel tank T2.

[0058] [Another embodiment] Other embodiments of the present invention will be described below. Note that the configurations of the embodiments described below are not limited to being applied alone, but may also be applied in combination with the configurations of other embodiments.

[0059] (1) In the above-described ammonia charging and storage system 100, the valve mechanism V is used as the cooling control means C1, but the cooling control means C1 may be a suction recovery means that, in the first step, when charging the liquid ammonia a1 through the supply path FR, sucks and recovers the ammonia gas ag through the recovery path RR to the liquid fuel supply facility S. In this case, the suction force of the discharge pump P1 that discharges the liquid ammonia a1 provided in the liquid fuel supply facility S may be utilized. When suction is involved, a configuration that does not include the valve mechanism described above can be adopted, or the pressure setting of the valve mechanism can be set below the cooling control stop temperature, and the pressure can be set to a level at which the ammonia storage material rapidly absorbs the ammonia.

[0060] (2) Regarding the operation of the above-mentioned ammonia filling and storage system 100, the filling of liquid ammonia a1 and the associated recovery of ammonia gas ag are started almost simultaneously. However, since the object of the present invention is to lower the temperature in the second fuel tank T2 to the cooling control stop temperature, if the ammonia storage material aA has absorbed ammonia and remains in this tank T2 as a liquid, prior to filling with liquid ammonia, for example, the pressure in the second fuel tank can be reduced by suction using the above-mentioned suction recovery means, and ammonia gas can be released from this second fuel tank. This reduces the degree of bumping of the supplied liquid ammonia while at the same time allowing the temperature in the second fuel tank to reach the cooling control stop temperature quickly.

[0061] That is, in constructing the ammonia filling and storage system 100, the cooling control means C1 may be a recovery and supply timing adjustment means (not shown) that, when filling liquid ammonia a1 via the supply path FR, releases ammonia gas ag via the recovery path RR prior to filling liquid ammonia a1 via the supply path FR. A time chart of such timing adjustment is shown in FIG. 6 corresponding to FIG.

[0062] (3) In the ammonia filling and storage system 100 described so far, the examples of recovering ammonia gas ag have been mainly described, but the ammonia gas ag can also be used as fuel f or even as a reducing agent, etc. When dealing with these applications, the ammonia may be discharged (external application) via the discharge path F0 to the side of each intended application without using the recovery path RR provided in the ammonia charging and storage system 100. However, even in this case, when filling the second fuel tank T2 with liquid ammonia a1, a cooling control means C1 is provided which executes a first step of cooling the second fuel tank T2 by releasing ammonia gas ag from the second fuel tank T2 to make the temperature inside the second fuel tank T2 equal to or lower than a cooling control stop temperature, which is a temperature at which ammonia maintains a liquid phase at the withstand pressure of the second fuel tank T2, and a filling control means C2 is provided which executes a second step of continuing the filling and completing the filling following the first step, thereby making it possible to fill and store the liquid ammonia a1 in the second fuel tank T2 having the ammonia storage material aA mixed therein, thereby achieving the object of the present invention.

[0063] In this case, the method of filling the liquid ammonia a1 is as follows: A liquid fuel supply facility S including a first fuel tank T1 for cooling and storing liquid ammonia a1 and a supply device for supplying liquid ammonia a1 from the first fuel tank T1; A method for filling liquid ammonia a1 in an ammonia filling and storage system 100, comprising: a tank for storing liquid ammonia a1 in a state in which an ammonia occlusion material aA that occludes ammonia and becomes liquid, and a second fuel tank T2 having an inlet in for receiving liquid ammonia a1 from the liquid fuel supply facility S and an outlet out for discharging ammonia, A supply line FR for supplying liquid ammonia a1 from the liquid fuel supply facility S to the second fuel tank T2; A discharge path FO is established for discharging ammonia from the second fuel tank T2, When liquid ammonia a1 is filled from the liquid fuel supply facility S into the second fuel tank T2, This is a method of performing a first step of cooling the second fuel tank T2 by releasing ammonia gas ag from the second fuel tank T2 through the established release path FO to make the temperature inside the second fuel tank T2 equal to or lower than a cooling control stop temperature, which is a temperature at which ammonia maintains a liquid phase at the withstand pressure of the second fuel tank T2, and then performing a second step of continuing the filling and completing the filling following the first step.

[0064] In the above embodiment, the second fuel tank T2 is provided in an automobile car, but it may also be used as a fuel tank for a small boat (not shown), for example. Furthermore, in the above embodiment, an example of a fuel cell that uses ammonia directly as fuel is shown, but since the present invention relates to the filling and storage of ammonia, any technology that separates hydrogen from ammonia and uses it can be adopted. [Explanation of symbols]

[0065] 100 Ammonia filling storage system FC fuel cell FR supply route F0 discharge path M electric motor P1 Discharge pump (supply device) RF cooling device RR Collection Route S Liquid fuel supply equipment T1 First Fuel Tank T2 Second Fuel Tank a1 Liquid ammonia (ammonia) ag Ammonia gas (ammonia) aA Ammonia storage material Car f fuel in Reception Out Payment outlet

Claims

1. A liquid fuel supply facility including a first fuel tank for cooling and storing liquid ammonia and a supply device for supplying liquid ammonia from the first fuel tank; A method for filling liquid ammonia in an ammonia filling and storage system comprising a tank for storing liquid ammonia in a state in which an ammonia occlusion material that occludes ammonia and becomes liquid is mixed, the second fuel tank having an intake port for receiving liquid ammonia from the liquid fuel supply facility and an outlet port for discharging ammonia, a supply line for supplying liquid ammonia from the liquid fuel supply facility to the second fuel tank; establishing a discharge path for discharging ammonia from the second fuel tank; When liquid ammonia is filled into the second fuel tank from the liquid fuel supply facility, A method for filling liquid ammonia, comprising: a first step of cooling the second fuel tank by releasing ammonia gas from the second fuel tank through the established release path, so as to make the temperature inside the second fuel tank equal to or lower than a cooling control stop temperature, which is a temperature at which ammonia maintains a liquid phase at the withstand pressure of the second fuel tank; and a second step of continuing filling following the first step to complete the filling.

2. A liquid fuel supply facility including a first fuel tank for cooling and storing liquid ammonia and a supply device for supplying liquid ammonia from the first fuel tank; A method for filling liquid ammonia in an ammonia filling and storage system comprising a tank for storing liquid ammonia in a state in which an ammonia occlusion material that occludes ammonia and becomes liquid is mixed, the second fuel tank having an intake port for receiving liquid ammonia from the liquid fuel supply facility and an outlet port for discharging ammonia, a supply line for supplying liquid ammonia from the liquid fuel supply facility to the second fuel tank; establishing a recovery path for recovering ammonia from the second fuel tank to the liquid fuel supply facility; When liquid ammonia is filled into the second fuel tank from the liquid fuel supply facility, A method for filling liquid ammonia, comprising: a first step of cooling the second fuel tank by releasing ammonia gas from the second fuel tank through the established recovery path, so as to make the temperature inside the second fuel tank equal to or lower than a cooling control stop temperature, which is a temperature at which ammonia maintains a liquid phase at the withstand pressure of the second fuel tank; and a second step of continuing filling following the first step to complete the filling.

3. 3. The method for filling liquid ammonia according to claim 1, wherein, when filling the liquid ammonia through the supply line, a pressure in the second fuel tank is adjusted to be equal to or lower than a withstand pressure set for the second fuel tank.

4. 3. The method for charging liquid ammonia according to claim 2, wherein when charging liquid ammonia via said supply path, in said first step, ammonia gas is suctioned and recovered via said recovery path into said liquid fuel supply facility.

5. 5. The method for charging liquid ammonia according to claim 2 or 4, wherein when charging liquid ammonia via the supply path, release of ammonia gas via the recovery path is carried out prior to charging of liquid ammonia via the supply path.

6. A liquid fuel supply facility including a first fuel tank for cooling and storing liquid ammonia and a supply device for supplying liquid ammonia from the first fuel tank; An ammonia filling and storage system comprising: a tank for storing liquid ammonia in a state in which an ammonia occlusion material that occludes ammonia and becomes liquid is mixed, the second fuel tank having an intake port for receiving liquid ammonia from the liquid fuel supply facility and an outlet port for discharging ammonia, a supply line for supplying liquid ammonia from the liquid fuel supply facility to the second fuel tank; a discharge path for discharging ammonia from the second fuel tank, When liquid ammonia is filled into the second fuel tank from the liquid fuel supply facility, An ammonia filling and storage system comprising: a cooling control means for executing a first step of cooling the second fuel tank by releasing ammonia gas from the second fuel tank through the established release path, and making the temperature inside the second fuel tank equal to or lower than a cooling control stop temperature, which is a temperature at which ammonia remains in a liquid phase at the withstand pressure of the second fuel tank; and a filling control means for executing a second step of continuing filling following the first step to complete the filling.

7. A liquid fuel supply facility including a first fuel tank for cooling and storing liquid ammonia and a supply device for supplying liquid ammonia from the first fuel tank; An ammonia filling and storage system comprising a tank for storing liquid ammonia in a state in which an ammonia occlusion material that occludes ammonia and becomes liquid is mixed, the second fuel tank having an inlet for receiving liquid ammonia from the liquid fuel supply facility and an outlet for discharging ammonia, a supply line for supplying liquid ammonia from the liquid fuel supply facility to the second fuel tank; a recovery path for recovering ammonia from the second fuel tank to the liquid fuel supply facility, When liquid ammonia is filled into the second fuel tank from the liquid fuel supply facility, An ammonia filling and storage system comprising: a cooling control means for executing a first step of cooling the second fuel tank by releasing ammonia gas from the second fuel tank through the established recovery path, and making the temperature inside the second fuel tank equal to or lower than a cooling control stop temperature, which is a temperature at which ammonia remains in a liquid phase at the withstand pressure of the second fuel tank; and a filling control means for executing a second step of continuing filling following the first step to complete the filling.

8. 8. The ammonia filling and storage system according to claim 6 or 7, wherein the cooling control means comprises a valve mechanism that adjusts the pressure in the second fuel tank to a pressure resistance set for the second fuel tank or less when the liquid ammonia is filled through the supply path.

9. 8. The ammonia filling and storage system according to claim 7, wherein the cooling control means is a suction and recovery means that, in the first step, when liquid ammonia is filled through the supply path, sucks and recovers ammonia gas through the recovery path to the liquid fuel supply equipment.

10. 10. The ammonia charging and storage system according to claim 7 or 9, wherein the cooling control means is a recovery and supply timing adjustment means for prioritizing the release of ammonia gas through the recovery line when the liquid ammonia is charged through the supply line.

11. 8. A supply and recovery device for establishing an ammonia charging and storage system according to claim 7, comprising: a supply path establishing means for receiving liquid ammonia from the liquid fuel supply facility and supplying the liquid ammonia to the receiving port of the second fuel tank; a recovery path establishing means for receiving ammonia from the discharge port of the second fuel tank and recovering it in the liquid fuel supply facility.

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