FUEL SUPPLY DEVICE AND METHOD FOR CONTROLLING FUEL SUPPLY DEVICE

Abstract

To stably supply fuel to a burner without upsizing a facility for storing the fuel.SOLUTION: A fuel supply device 100 supplies fuel containing ammonia to a burner 210. The fuel supply device 100 comprises a separation tower 20 for separating an ammonia aqueous solution and an ammonia gas generated by vaporization of the ammonia aqueous solution, a supply pipe L1 for supplying the ammonia gas to the burner 210 from the separation tower 20, and a heating part 40 for heating the ammonia aqueous solution held by the separation tower 20, thereby vaporizing it, and adjusting ammonia concentration in the ammonia gas to be guided to the supply pipe L1.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a fuel supply device and a method for controlling the fuel supply device. [Background technology]

[0002] Conventionally, there is known a technology for reducing the amount of carbon dioxide generated by burning ammonia, which is a fuel that does not generate carbon dioxide when burned, together with a solid fuel such as coal (see, for example, Patent Document 1). The combustion device disclosed in Patent Document 1 supplies solid fuel and gaseous ammonia to a burner, and co-burns the solid fuel and ammonia. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-203631 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, there are the following problems when using gaseous ammonia as fuel. A large amount of energy is required to vaporize liquefied ammonia (pressurized or refrigerated), which is the general form in which ammonia is distributed, to produce gaseous ammonia. In addition, compared to other gaseous fuels (methane, propane, natural gas, etc.), ammonia has a low calorific value per unit volume. In addition, heat loss (exhaust gas loss) is large due to moisture generated by the combustion of ammonia. As a result, the amount of fuel required to obtain the desired energy increases, and fuel storage and supply facilities become larger.

[0005] On the other hand, by using liquefied ammonia, it is possible to avoid the need for larger fuel storage and supply facilities compared to gaseous ammonia, but the following issues arise. Liquefied ammonia has a high vapor pressure at room temperature (approximately 0.75 MPaG at 20°C), and if used in a room temperature environment, it may vaporize in the fuel system and not be able to be steadily supplied to the combustion equipment. Also, to store liquefied ammonia in liquid form, the fuel storage and supply facility needs to have the functions of pressurization and cooling to prevent the liquefied ammonia from vaporizing.

[0006] The present disclosure has been made in consideration of the above circumstances, and aims to provide a fuel supply device and a control method thereof that are capable of stably supplying fuel to a burner without increasing the size of the fuel storage facility. [Means for solving the problem]

[0007] A fuel supply device according to one aspect of the present disclosure is a fuel supply device that supplies a fuel containing ammonia to a burner, and includes a separation unit that separates an aqueous ammonia solution from an ammonia gas vaporized from the aqueous ammonia solution, a supply pipe that supplies the ammonia gas or the aqueous ammonia solution obtained by condensing the ammonia gas from the separation unit to the burner, and a heating unit that heats the aqueous ammonia solution held in the separation unit to vaporize it, thereby adjusting the ammonia concentration in the ammonia gas guided to the supply pipe.

[0008] A control method for a fuel supply device according to one aspect of the present disclosure is a control method for a fuel supply device that supplies a fuel containing ammonia to a burner, the fuel supply device having a separation unit that separates an ammonia aqueous solution from an ammonia gas vaporized from the ammonia aqueous solution, and a supply piping that supplies the ammonia gas or the ammonia aqueous solution obtained by condensing the ammonia gas from the separation unit to the burner, and including a heating step of heating the ammonia aqueous solution held in the separation unit to vaporize it, thereby adjusting the ammonia concentration in the ammonia gas guided to the supply piping. Effect of the Invention

[0009] According to the present disclosure, it is possible to provide a fuel supply device and a control method thereof that can stably supply fuel to a burner without increasing the size of the fuel storage facility. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic configuration diagram showing a boiler system according to a first embodiment of the present disclosure. [Diagram 2] 1 is a graph showing a gas-liquid equilibrium curve of an aqueous ammonia solution at atmospheric pressure. [Diagram 3] FIG. 4 is a schematic configuration diagram showing a boiler system according to a second embodiment of the present disclosure. [Figure 4] FIG. 11 is a schematic configuration diagram showing a boiler system according to a third embodiment of the present disclosure. [Diagram 5] FIG. 11 is a schematic configuration diagram showing a boiler system according to a fourth embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] [First embodiment] A boiler system according to a first embodiment of the present disclosure will be described below with reference to the drawings. The boiler system of this embodiment includes a fuel supply device 100 and a boiler 200 that generates steam by combusting liquid fuel supplied from the fuel supply device 100. The steam generated by the boiler 200 is used, for example, as power to rotate a steam turbine (not shown) connected to a generator (not shown).

[0012] The fuel supply device 100 of this embodiment is a device that vaporizes an aqueous ammonia solution to generate a mixture of ammonia and water vapor (hereinafter referred to as ammonia gas), and supplies the mixture to the burner 210 of the boiler 200. FIG. 2 is a graph showing a gas-liquid equilibrium curve of an aqueous ammonia solution at atmospheric pressure. As shown in FIG. 2, when the weight percent concentration of the aqueous ammonia solution is any concentration greater than 0 and less than 100, there is no azeotropic point between water and ammonia. Therefore, by heating the aqueous ammonia solution to the boiling point or higher, a fuel gas (ammonia gas) of a desired concentration according to the heating temperature can be generated.

[0013] In this embodiment, the concentration of the aqueous ammonia solution stored in the storage tank 10 is, for example, 40 weight percent or less. By setting the weight percent concentration of the aqueous ammonia solution to 40 or less, the temperature of the aqueous ammonia solution at atmospheric pressure can be maintained at or below room temperature, thereby suppressing evaporation of the aqueous ammonia solution.

[0014] In this embodiment, the concentration of the aqueous ammonia solution stored in the storage tank 10 is preferably 10 weight percent or less. By setting the weight percent concentration of the aqueous ammonia solution to 10 or less, it is possible to minimize adverse effects on the environment in the event that ammonia gas vaporized from the aqueous ammonia solution leaks into the atmosphere.

[0015] As shown in FIG. 1, the fuel supply device 100 includes a storage tank (storage section) 10, a separation tower (separation section) 20, a supply pump 30, a heating section 40, a flow control valve 50, a flow control valve 60, a flow control valve 70, a control section 90, a supply pipe L1, a transport pipe L2, and a recovery pipe L3.

[0016] The supply pipe L1 is a pipe that guides ammonia gas from the separation tower 20 to the burner 210. The flow rate of the ammonia gas flowing through the supply pipe L1 is detected by a flow rate detection unit 51 and transmitted to the control unit 90. The transport pipe L2 is a pipe that transports the aqueous ammonia solution from the storage tank 10 to the separation tower 20. The recovery pipe L3 is a pipe that is connected to the lower part of the separation tower 20 and guides the aqueous ammonia solution (separated water) held in the separation tower 20 to a recovery facility (not shown). The flow rate of the aqueous ammonia solution flowing through the recovery pipe L3 is detected by a flow rate detection unit 71 and transmitted to the control unit 90.

[0017] The storage tank 10 is a tank for storing an aqueous ammonia solution. The storage tank 10 is connected to the separation tower 20 via a transfer pipe L2.

[0018] The separation tower 20 holds an aqueous ammonia solution and ammonia gas obtained by vaporizing the aqueous ammonia solution. The lower layer side of the separation tower 20 is a liquid phase region A1 in which the aqueous ammonia solution is held. The upper layer side of the separation tower 20 is a gas phase region A2 in which ammonia gas is held. The separation tower 20 may have a structure of a distillation tower, for example, in order to improve the separation efficiency and separation accuracy of the aqueous ammonia solution and the ammonia gas. Specifically, a member (packing) for promoting gas-liquid contact or a tray for holding the liquid phase may be installed in the gas phase region A2 of the separation tower 20.

[0019] The temperature of the ammonia gas supplied from the gas phase region A2 of the separation tower 20 to the burner 210 via the supply pipe L1 is detected by the temperature detection unit 21. The temperature of the ammonia gas detected by the temperature detection unit 21 is transmitted to the control unit 90. The amount of the aqueous ammonia solution held in the liquid phase region A1 of the separation tower 20 is detected by the aqueous ammonia solution detection unit 22. The aqueous ammonia solution detection unit 22 detects the amount of the aqueous ammonia solution held in the separation tower 20, for example, by detecting the height of the liquid level of the aqueous ammonia solution held in the separation tower 20. The amount of the aqueous ammonia solution detected by the aqueous ammonia solution detection unit 22 is transmitted to the control unit 90.

[0020] The supply pump 30 is a device that supplies the aqueous ammonia solution from the storage tank 10 to the separation tower 20. The supply pump 30 is disposed in a transfer pipe L2 that transfers the aqueous ammonia solution from the storage tank 10 to the separation tower 20.

[0021] The heating unit 40 is a device that adjusts the ammonia concentration in the ammonia gas introduced to the supply pipe L1 by heating the ammonia aqueous solution held in the separation tower 20 to a temperature equal to or higher than the boiling point thereof to vaporize the ammonia aqueous solution. The heating unit 40 heats the ammonia aqueous solution held in the liquid phase region A1 of the separation tower 20 with a heater 41 to vaporize the ammonia aqueous solution. The heating unit 40 heats the heater 41 so as to generate an amount of heat corresponding to a control signal transmitted from the control unit 90.

[0022] The flow rate control valve 50 is a device disposed in the supply pipe L1 and controls the flow rate of ammonia gas supplied from the gas phase region A2 of the separation tower 20 to the burner 210. The opening degree of the flow rate control valve 50 is controlled by a control signal transmitted from the control unit 90 so that the flow rate of ammonia gas detected by a flow rate detection unit 51 disposed in the supply pipe L1 becomes a predetermined set flow rate. The flow rate of ammonia gas supplied to the burner 210 may be controlled based on the supply pressure to the burner 210.

[0023] The flow rate control valve 60 is a device disposed in the transfer pipe L2 and controls the flow rate of the aqueous ammonia solution supplied from the storage tank 10 to the separation tower 20. The opening degree of the flow rate control valve 60 is controlled by a control signal transmitted from the control unit 90 so that the amount of the aqueous ammonia solution detected by the aqueous ammonia solution detection unit 22 becomes a predetermined amount. Note that instead of the flow rate control valve 60, the supply pump 30 may be a positive displacement pump such as a screw pump, and the rotation speed of an electric motor (not shown) that drives the supply pump 30 may be controlled by a control signal transmitted from the control unit 90 to control the flow rate of the aqueous ammonia solution.

[0024] The flow rate control valve 70 is a device disposed in the recovery pipe L3 and controls the flow rate of the aqueous ammonia solution (separated water) recovered to a recovery facility (not shown) from the liquid phase region A1 of the separation tower 20. The valve opening of the flow rate control valve 70 is controlled by a control signal transmitted from the control unit 90 so that the flow rate of the aqueous ammonia solution detected by a flow rate detection unit 71 disposed in the recovery pipe L3 becomes a predetermined set flow rate.

[0025] The control unit 90 is a device that controls each part of the fuel supply device 100. The control unit 90 controls the opening of the flow rate regulating valve 50 so that the flow rate detected by the flow rate detection unit 51 becomes a predetermined set flow rate. The control unit 90 controls the heating unit 40 based on the temperature detected by the temperature detection unit 21 so that the temperature of the ammonia gas becomes a predetermined set temperature. The control unit 90 sets a temperature according to the ammonia concentration in the ammonia gas supplied to the burner 210 as the predetermined set temperature of the ammonia gas.

[0026] The control unit 90 may set a temperature according to a load command (required heat input) to the burner 210 as the predetermined set temperature of the ammonia gas. That is, when the burner load command is high, the temperature is set so that the ammonia concentration is high, thereby obtaining ammonia gas with a large calorific value per unit volume. On the other hand, when the burner load command is low, the temperature is set so that the ammonia concentration is low, thereby obtaining ammonia gas with a small calorific value per unit volume. This makes it possible to obtain a rate of change in the heat input that is larger than the rate of change in the fuel flow rate. Ammonia is known to be inferior in combustibility to hydrocarbon fuels (methane, propane, etc.), and the flow rate change range that allows stable combustion in the burner may be smaller than that of hydrocarbon fuels. In such a case, it is effective to change the ammonia concentration according to the burner load command.

[0027] The control unit 90 adjusts the opening of the flow rate control valve 60 so that the amount of ammonia solution detected by the ammonia solution detection unit 22 becomes a predetermined amount. The control unit 90 adjusts the opening of the flow rate control valve 70 so that the flow rate of the ammonia solution (separated water) detected by the flow rate detection unit 71 becomes a predetermined set flow rate.

[0028] The functions and effects of the fuel supply device 100 of the present embodiment described above will be described. According to the fuel supply device 100 of this embodiment, the aqueous ammonia solution supplied to the separation tower 20 has a higher boiling point than liquefied ammonia, and maintains a liquid state at the temperature at which the fuel supply device 100 is used. Therefore, compared to the case where ammonia gas is supplied to the burner 210, the equipment for storing the fuel can be made smaller. Also, compared to the case where liquefied ammonia is supplied to the burner 210, there is no need to add a pressurizing / cooling function to the equipment for storing the fuel, and the equipment can be simplified. Also, by heating the aqueous ammonia solution held in the separation tower 20 by the heating unit 40, the aqueous ammonia solution is vaporized, and the ammonia concentration in the ammonia gas supplied to the burner 210 is adjusted. In this way, the fuel supply device 100 according to this embodiment can stably supply fuel to the burner 210 without increasing the size and complexity of the fuel storage facility. In addition, the moisture in the aqueous ammonia solution supplied from the storage tank 10 is separated as separated water, thereby reducing the moisture in the ammonia gas. This reduces the moisture generated by combustion in the burner 210, thereby reducing exhaust gas loss.

[0029] According to the fuel supply device 100 of the present embodiment, the supply pump 30 transports the aqueous ammonia solution from the storage tank 10 to the separation tower 20 via the transport pipe L2, and the aqueous ammonia solution is heated by the heating unit 40 in the separation tower 20, thereby adjusting the ammonia concentration in the ammonia gas. Therefore, only a necessary amount of the aqueous ammonia solution stored in the storage tank 10 can be transported by the supply pump 30 to the separation tower 20 and used as fuel for the burner 210.

[0030] According to the fuel supply device 100 of this embodiment, the control unit 90 controls the heating unit 40 so that the temperature of the ammonia gas becomes the set temperature, thereby making it possible to make the ammonia concentration in the ammonia gas introduced to the supply pipe L1 a concentration corresponding to a predetermined set temperature. Also, the control unit 90 sets the set temperature in response to a load command to the burner 210, so that ammonia gas of an appropriate concentration in response to the load command to the burner 210 can be introduced to the supply pipe L1.

[0031] According to the fuel supply device 100 of this embodiment, by setting the weight percent concentration of the ammonia aqueous solution to 40 or less, the temperature of the ammonia aqueous solution can be maintained at or below room temperature, thereby suppressing evaporation of the ammonia aqueous solution. Also, by setting the weight percent concentration of the ammonia aqueous solution to 10 or less, adverse effects on the environment in the event that ammonia gas evaporated from the ammonia aqueous solution leaks into the atmosphere can be minimized.

[0032] Second Embodiment Next, a fuel supply device 100A according to a second embodiment of the present disclosure will be described with reference to Fig. 3. This embodiment is a modified example of the first embodiment, and is the same as the first embodiment except as otherwise specifically described below, and therefore the description below will be omitted.

[0033] The fuel supply device 100A of this embodiment guides the ammonia gas supplied from the separation tower 20 to the supply pipe L1 directly to the burner 210. In contrast, the fuel supply device 100A of this embodiment condenses the ammonia gas supplied from the separation tower 20 to the supply pipe L1 to generate an ammonia aqueous solution (liquid ammonia fuel) and guides it to the burner 210. The ammonia concentration of the ammonia aqueous solution obtained by condensing the ammonia gas is higher than the concentration of the ammonia aqueous solution supplied from the storage tank 10.

[0034] The fuel supply device 100A of the present embodiment shown in FIG. 3 differs from the fuel supply device 100 of the first embodiment in that it includes a condensation section 80, a supply pump 83, a flow rate control valve 84, and a flow rate detection section 85 downstream of the flow rate detection section 51 of the supply piping L1.

[0035] The condensation unit 80 is a device that is disposed in the supply pipe L1 and condenses the ammonia gas supplied from the separation tower 20 to produce an aqueous ammonia solution. The supply pipe L1 supplies the aqueous ammonia solution produced by the condensation unit 80 to the burner 210. The condensation unit 80 has a condenser 81 and a cooling unit 82.

[0036] The condenser 81 holds ammonia gas supplied from the supply pipe L1 and an aqueous ammonia solution obtained by condensing the ammonia gas. The cooling unit 82 is a device that cools the ammonia gas supplied from the supply pipe L1 to the condenser 81 to a temperature lower than the condensation temperature.

[0037] The supply pump 83 is disposed in the supply pipe L1 and is a device for supplying the aqueous ammonia solution from the condenser 80 to the burner 210.

[0038] The flow rate control valve 84 is disposed in the supply pipe L1 and is a device for adjusting the flow rate of the aqueous ammonia solution supplied to the burner 210. The opening degree of the flow rate control valve 84 is adjusted by a control signal transmitted from the control unit 90 so that the flow rate of the aqueous ammonia solution detected by a flow rate detection unit 85 disposed in the supply pipe L1 becomes a predetermined set flow rate. Note that instead of the flow rate control valve 84, the supply pump 83 may be a positive displacement pump such as a screw pump, and the rotation speed of an electric motor (not shown) that drives the supply pump 83 may be controlled by a control signal transmitted from the control unit 90 to adjust the flow rate of the aqueous ammonia solution.

[0039] According to the fuel supply device 100A of the present embodiment, the ammonia gas supplied from the separation tower 20 to the supply pipe L1 is condensed in the condenser 80, and an aqueous ammonia solution (liquid ammonia fuel) can be supplied to the burner 210 via the supply pipe L1. This makes it possible to use a fuel containing ammonia, for example, even if the existing combustion equipment such as a burner uses liquid fuel, without modifying the combustion equipment.

[0040] Third Embodiment Next, a fuel supply device 100B according to a third embodiment of the present disclosure will be described with reference to Fig. 4. This embodiment is a modified example of the first embodiment, and is the same as the first embodiment except as otherwise specifically described below, and therefore the description below will be omitted.

[0041] The fuel supply device 100B of this embodiment is a modified example of the second embodiment, and is the same as the first embodiment except as otherwise specifically described below, and therefore the description thereof will be omitted below. As shown in Fig. 4, the fuel supply device 100B of this embodiment differs from the fuel supply device 100A of the second embodiment in that a return pipe L4, a flow rate adjustment valve 86, and a flow rate detection unit 87 are added.

[0042] The reflux pipe L4 is a pipe that guides the aqueous ammonia solution produced by the condensation section 80 to the separation tower 20 from the downstream side of the condensation section 80 of the supply pipe L1.

[0043] The flow rate control valve 86 is disposed in the reflux piping L4 and is a device for adjusting the flow rate of the aqueous ammonia solution supplied to the separation tower 20. The opening degree of the flow rate control valve 86 is adjusted by a control signal transmitted from the control unit 90 so that the flow rate of the liquefied ammonia detected by a flow rate detection unit 87 disposed in the reflux piping L4 becomes a predetermined set flow rate.

[0044] The fuel supply device 100B of the present embodiment controls the heating unit 40, the flow rate control valve 50, and the condensation unit 80 so that an amount of ammonia aqueous solution produced in the condensation unit 80 is greater than the amount of the ammonia aqueous solution supplied to the burner 210. Then, the control unit 90 controls the aperture of the flow rate control valve 84 and the aperture of the flow rate control valve 86 so that a predetermined set flow rate of the ammonia aqueous solution is supplied from the supply pipe L1 to the burner 210.

[0045] According to the fuel supply device 100B of the present embodiment, a part of the aqueous ammonia solution condensed by the condenser 80 is returned to the separation tower 20 through the return pipe L4, and the flow rate of the liquefied ammonia returned to the separation tower 20 can be adjusted by the flow control valve 86. Therefore, even if the flow rate of the aqueous ammonia solution supplied to the burner 210 changes based on a load command to the burner 210, the ammonia concentration in the ammonia gas separated in the separation tower 20 can be stably adjusted.

[0046] [Fourth embodiment] Next, a fuel supply device 100C according to a fourth embodiment of the present disclosure will be described with reference to Fig. 5. This embodiment is a modified example of the third embodiment, and is the same as the third embodiment except as otherwise specifically described below, and the description thereof will be omitted below. As shown in Fig. 5, the fuel supply device 100C of this embodiment differs from the fuel supply device 100B of the third embodiment in that a separation water tank 72, a flow rate adjustment valve 73, a flow rate detection unit 74, and a raw material pipe L5 are added.

[0047] The recovery pipe L3 in this embodiment guides the aqueous ammonia solution from the separation tower 20 to the storage tank 10. Here, the ammonia concentration of the aqueous ammonia solution (separated water) guided to the storage tank 10 by the recovery pipe L3 is lower than the concentration of the aqueous ammonia solution stored in the storage tank 10 due to evaporation in the separation tower 20.

[0048] The aqueous ammonia solution is guided from the separation tower 20 to the recovery pipe L3 and has its flow rate adjusted by the flow control valve 70, and is temporarily stored in the separated water tank 72. The aqueous ammonia solution stored in the separated water tank 72 is mixed with the aqueous ammonia solution flowing through the raw material pipe L5 via the flow control valve 73.

[0049] The flow rate control valve 73 is disposed in the recovery pipe L3 and is a device for adjusting the flow rate of the aqueous ammonia solution introduced to the raw material pipe L5. The aperture of the flow rate control valve 73 is adjusted by a control signal transmitted from the control unit 90 according to the flow rate of the aqueous ammonia solution detected by a flow rate detector 74 disposed in the raw material pipe L5. The control unit 90 adjusts the aperture of the flow rate control valve 73 so that the aqueous ammonia solution flowing through the raw material pipe L5 and the aqueous ammonia solution introduced from the recovery pipe L3 are mixed to form an aqueous ammonia solution of a desired concentration. That is, the aqueous ammonia solution (separated water) introduced from the recovery pipe L3 is used to dilute the aqueous ammonia solution (raw material) flowing through the raw material pipe L5.

[0050] According to the fuel supply device 100C of the present embodiment, the aqueous ammonia solution recovered from the separation tower 20 is guided to the storage tank 10, whereby the amount of ammonia gas required for combustion in the burner 210 is generated in the separation tower 20, while the aqueous ammonia solution in which a part of the ammonia has evaporated and the concentration has decreased can be recovered in the storage tank 10 and reused.

[0051] Moreover, the ammonia concentration when stored in the storage tank 10 can be selected without being limited to the concentration of the aqueous ammonia received as the raw material. That is, by setting the ammonia concentration according to the environmental temperature, it is possible to suppress the evaporation of the aqueous ammonia in the storage tank 10. Furthermore, since the concentration of the aqueous ammonia as the raw material can be made higher than the concentration when stored, it is possible to improve the volume efficiency when transporting the raw material.

[0052] The fuel supply device according to the embodiment described above can be understood, for example, as follows. A fuel supply device (100) according to the present disclosure is a fuel supply device (100) that supplies a fuel containing ammonia to a burner (210), and includes a separation section (20) that separates an aqueous ammonia solution from ammonia gas obtained by vaporizing the aqueous ammonia solution, a supply pipe (L1) that supplies the ammonia gas or the aqueous ammonia solution obtained by condensing the ammonia gas from the separation section to the burner, and a heating section (40) that heats the aqueous ammonia solution held in the separation section to vaporize it, thereby adjusting the ammonia concentration in the ammonia gas that is led to the supply pipe.

[0053] According to the fuel supply device of the present disclosure, the aqueous ammonia solution supplied to the separation section has a higher boiling point than liquefied ammonia. Therefore, the equipment for storing the fuel can be made smaller than when liquefied ammonia is supplied to the separation section. Furthermore, by heating the aqueous ammonia solution held in the separation section by the heating section, the aqueous ammonia solution is vaporized and the ammonia concentration in the ammonia gas introduced to the supply pipe is adjusted. Thus, according to the fuel supply device of the present disclosure, it is possible to stably supply fuel to the burner without enlarging the size of the equipment for storing the fuel.

[0054] The fuel supply device according to the present disclosure may be configured to include a storage section (10) that stores the ammonia aqueous solution, a transport piping (L2) that transports the ammonia aqueous solution from the storage section to the separation section, and a supply pump (30) that is disposed in the transport piping and supplies the ammonia aqueous solution from the storage section to the separation section. According to the fuel supply device of this configuration, the supply pump transports the ammonia aqueous solution from the storage section to the separation section through the transport piping, and the ammonia concentration in the ammonia gas is adjusted by heating the ammonia aqueous solution by the heating section in the separation section. Therefore, the ammonia aqueous solution stored in the storage section can be transported by the supply pump in a required amount to the separation section and used as fuel for the burner.

[0055] The fuel supply device according to the present disclosure may further include a control unit (90) that controls the heating unit so that the temperature of the aqueous ammonia solution becomes a set temperature. According to the fuel supply device having the present configuration, the control unit controls the heating unit so that the temperature of the ammonia gas becomes the set temperature, whereby the ammonia concentration in the ammonia gas introduced into the supply piping can be set to a concentration corresponding to the predetermined set temperature.

[0056] In the fuel supply device having the above configuration, the control unit may set the set temperature in response to a load command to the burner. According to the fuel supply device of this aspect, the control unit sets the set temperature in accordance with the load command to the burner, so that ammonia gas of an appropriate concentration in accordance with the load command to the burner can be introduced into the supply piping.

[0057] The fuel supply device according to the present disclosure may include a condensation section (80) that is disposed in the supply piping and that condenses the ammonia gas supplied from the separation tower (20) to produce the liquefied ammonia, and the supply piping may be configured to supply the liquefied ammonia to the burner. According to the fuel supply device of this configuration, the ammonia gas supplied from the separation unit to the supply pipe can be condensed in the condenser, and the aqueous ammonia solution can be supplied to the burner through the supply pipe. This makes it possible to use a fuel containing ammonia without modifying the combustion equipment, for example, even if the existing combustion equipment such as a burner uses liquid fuel.

[0058] The fuel supply device having the above configuration may further include a reflux piping (L4) that guides the liquefied ammonia generated by the condensation section from a downstream side of the condensation section of the supply piping to the separation tower, and a flow rate control valve (86) that is disposed in the reflux piping and adjusts a flow rate of the liquefied ammonia guided to the separation tower via the reflux piping. According to the fuel supply device of this aspect, a part of the aqueous ammonia solution condensed by the condenser is returned to the separation section through the return pipe, and the flow rate of the liquefied ammonia returned to the separation section can be adjusted by the flow control valve. Therefore, even if the flow rate of the aqueous ammonia solution supplied to the burner changes based on a load command to the burner, the ammonia concentration in the ammonia gas separated in the separation section can be stably adjusted.

[0059] The fuel supply device according to the present disclosure may further include a recovery pipe (L4) that guides a portion of the aqueous ammonia solution from the separation section to the storage section. According to the fuel supply device of this configuration, the aqueous ammonia solution recovered from the separation section is guided to the storage section, whereby the amount of ammonia gas required for combustion in the burner is generated in the separation section, while the aqueous ammonia solution with a reduced concentration due to some of the ammonia being vaporized can be recovered in the storage section and reused.

[0060] In addition, the ammonia concentration when stored in the storage section can be selected without being limited to the concentration of the aqueous ammonia solution received as the raw material. That is, by setting the ammonia concentration according to the environmental temperature, it is possible to suppress the evaporation of the aqueous ammonia solution in the storage section. Furthermore, since the concentration of the aqueous ammonia solution as the raw material can be made higher than the concentration when stored, it is possible to improve the volumetric efficiency when transporting the raw material.

[0061] In the fuel supply device according to the present disclosure, the concentration of the aqueous ammonia solution supplied to the separation tower is preferably 40 weight percent or less, and more preferably 10 weight percent or less. According to the fuel supply device of this configuration, by setting the weight percent concentration of the ammonia aqueous solution to 40 or less, the temperature of the ammonia aqueous solution can be maintained at or below room temperature at atmospheric pressure, thereby minimizing the amount of ammonia gas vaporized from the ammonia aqueous solution. Also, by setting the weight percent concentration of the ammonia aqueous solution to 10 or less, it is possible to minimize adverse effects on the environment in the event that ammonia gas vaporized from the ammonia aqueous solution leaks into the atmosphere.

[0062] The control method of the fuel supply device according to the embodiment described above can be understood, for example, as follows. A control method for a fuel supply device according to the present disclosure is a control method for a fuel supply device (100) that supplies a fuel containing ammonia to a burner (210), the fuel supply device having a separation section (20) that separates an aqueous ammonia solution from an ammonia gas obtained by vaporizing the aqueous ammonia solution, and a supply pipe (L1) that supplies the ammonia gas or the aqueous ammonia solution obtained by condensing the ammonia gas from the separation section to the burner, and including a heating step of heating the aqueous ammonia solution held in the separation section to vaporize it, thereby adjusting the ammonia concentration in the ammonia gas introduced to the supply pipe.

[0063] According to the control method of the fuel supply device of the present disclosure, the ammonia aqueous solution supplied to the separation section has a higher boiling point than liquefied ammonia, and maintains a liquid state at the temperature at which the fuel supply device is used. Therefore, compared to the case where ammonia gas is supplied to the burner, the equipment for storing the fuel can be made smaller. Also, compared to the case where liquefied ammonia is supplied to the burner, there is no need to add a pressurizing / cooling function to the equipment for storing the fuel, and the equipment can be simplified. Also, by heating the ammonia aqueous solution held in the separation section by the heating process, the ammonia aqueous solution is vaporized, and the ammonia concentration in the ammonia gas supplied to the burner is adjusted. Thus, according to the control method of the fuel supply device of the present disclosure, it is possible to stably supply fuel to the burner without making the equipment for storing the fuel larger and more complicated. Also, by separating the moisture in the ammonia aqueous solution supplied from the storage section as separated water, the moisture in the ammonia gas is reduced. Therefore, the moisture generated by combustion in the burner is reduced, and the exhaust gas loss can be reduced. [Explanation of symbols]

[0064] 10 Storage tank (storage section) 20 Separation column (separation section) 21 Temperature detection section 22 Ammonia aqueous solution detector 30,83 Supply pump 40 Heating section 41 Heater 50,60,70,73,84,86 Flow control valve 51, 71, 74, 85, 87 Flow rate detector 72 Separation water tank 80 Condenser 81 Condenser 82 Cooling section 90 Control section 100,100A,100B,100C Fuel supply device 200 Boiler 210 Burner L1 Supply pipe L2 Conveyor pipe L3 Recovery pipe L4 Return pipe L5 Raw material piping

Claims

1. A fuel supply device that supplies a fuel containing ammonia to a burner, A separation section that separates the ammonia aqueous solution from the ammonia gas vaporized from the ammonia aqueous solution; a supply pipe for supplying the ammonia gas or an aqueous ammonia solution obtained by condensing the ammonia gas from the separation unit to the burner; a heating unit that heats the aqueous ammonia solution held in the separation unit to vaporize it, thereby adjusting the ammonia concentration in the ammonia gas introduced to the supply pipe.

2. A storage section for storing the aqueous ammonia solution; a conveying pipe for conveying the aqueous ammonia solution from the storage section to the separation section; 2. The fuel supply device according to claim 1, further comprising: a supply pump disposed in the transfer pipe and configured to supply the aqueous ammonia solution from the storage section to the separation section.

3. 3. The fuel supply device according to claim 1, further comprising a control unit that controls the heating unit so that the temperature of the ammonia gas becomes a set temperature.

4. The fuel supply device according to claim 3 , wherein the control unit sets the set temperature in accordance with a load command to the burner.

5. a condensation section that is disposed in the supply pipe and that condenses the ammonia gas supplied from the separation section to generate an aqueous ammonia solution; 5. The fuel supply device according to claim 1, wherein the supply pipe supplies the aqueous ammonia solution to the burner.

6. a reflux pipe that guides the aqueous ammonia solution generated by the condensation section from a downstream side of the condensation section of the supply pipe to the separation section; 6. The fuel supply device according to claim 5, further comprising: a flow rate regulating valve that is disposed in the reflux pipe and that regulates a flow rate of the aqueous ammonia solution that is guided to the separation section via the reflux pipe.

7. 3. The fuel supply device according to claim 2, further comprising a recovery pipe configured to guide a portion of the aqueous ammonia solution from the separation section to the storage section.

8. 8. The fuel supply device according to claim 1, wherein the concentration of the aqueous ammonia solution supplied to the separation section is 40 weight percent or less.

9. 9. The fuel supply device according to claim 8, wherein the concentration of the aqueous ammonia solution supplied to the separation section is 10 weight percent or less.

10. A method for controlling a fuel supply device that supplies a fuel containing ammonia to a burner, comprising the steps of: The fuel supply device includes: A separation section that separates the ammonia aqueous solution from the ammonia gas vaporized from the ammonia aqueous solution; a supply pipe for supplying the ammonia gas or an aqueous ammonia solution obtained by condensing the ammonia gas from the separation unit to the burner, A control method for a fuel supply device comprising: a heating step of heating the aqueous ammonia solution held in the separation section to vaporize it, thereby adjusting the ammonia concentration in the ammonia gas introduced into the supply pipe.

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