Ammonia reforming combustion system and ammonia reforming combustion method

Abstract

To provide an ammonia reforming combustion system capable of stably generating a reformed gas without separately providing heating means such as a heater and thereby performing stable combustion.SOLUTION: A reformer comprises: a reformer 5 for reforming ammonia gas by using heat of a high temperature gas generated by combustion of a gas mixture of ammonia gas supplied by an ammonia gas supply device 3 and reforming air supplied by a reforming air supply device 11 to produce a reformed gas containing hydrogen; a combustor 7 for combusting a gas mixture of the reformed gas produced by the reformer 5 and combustion air supplied by a combustion air supply device 13; and reforming air supply amount control means 59, 82 for controlling a supply amount (Q1) of the reforming air so that a ratio (Q1 / Q2) of the supply amount (Q1) of the reforming air to a supply amount (Q2) of ammonia gas becomes a predetermined range and / or a temperature of the high temperature gas becomes a predetermined temperature range.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an ammonia reforming combustion system including an ammonia gas supply device for supplying ammonia gas, a reforming air supply device for supplying reforming air, and a combustion air supply device for supplying combustion air, and an ammonia reforming combustion method performed using the ammonia reforming combustion system.

Background Art

[0002] For example, in a waste incinerator, fossil fuels such as city gas and kerosene are used as the start-up fuel for the operation of the furnace. In recent years, in the direction of decarbonization, conversion from fossil fuels to carbon-free fuels is required. As carbon-free fuels, hydrogen and ammonia have attracted attention, and the movement toward their spread has been accelerating.

[0003] Although hydrogen is considered difficult to store, ammonia can be stored relatively easily, and its introduction is expected. However, ammonia has poor combustibility, and when ammonia is burned alone, nitrogen oxides and unburned ammonia are generated. Therefore, the development of a co-firing technology for burning ammonia mixed with fossil fuels such as coal and natural gas has been carried out. In addition, a combustion device that reforms and burns ammonia has been proposed (for example, see Patent Document 1).

[0004] In the combustion device described in Patent Document 1, a catalyst housing portion that houses a catalyst for decomposing ammonia gas into hydrogen gas and nitrogen gas is provided inside a reformer into which ammonia gas is introduced, and a heater is provided as heating means for activating the decomposition action of ammonia gas by the catalyst.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

[0006] The above co-firing technology does not achieve complete decarbonization because it uses fossil fuels. Furthermore, the combustion device described in Patent Document 1 has the problem of becoming large because it requires a separate heater as a heating means to activate the decomposition of ammonia gas by the catalyst.

[0007] The present invention has been made in view of the above problems, and aims to provide an ammonia reforming combustion system and an ammonia reforming combustion method that can stably generate reformed gas without the need to separately provide heating means such as a heater, thereby enabling stable combustion. [Means for solving the problem]

[0008] The characteristic configuration of the ammonia reforming combustion system according to the present invention, which solves the above problems, is as follows: An ammonia reforming combustion system comprising an ammonia gas supply device for supplying ammonia gas, a reforming air supply device for supplying reforming air, and a combustion air supply device for supplying combustion air, A reformer that uses the heat of a high-temperature gas generated by the combustion of a mixed gas of ammonia gas supplied by the ammonia gas supply device and reformed air supplied by the reformed air supply device to reform the ammonia gas and produce a reformed gas containing hydrogen, A combustor burns a mixture of reformed gas produced by the reformer and combustion air supplied by the combustion air supply device. A reforming air supply amount control means controls the supply amount of reforming air (Q1) so that the ratio (Q1 / Q2) of the supply amount of reforming air (Q1) to the supply amount of ammonia gas (Q2) is within a predetermined range, and / or the temperature of the high-temperature gas is within a predetermined temperature range. The goal is to provide for it.

[0009] In this ammonia reforming combustion system, the supply amount of reforming air (Q1) is controlled so that the ratio (Q1 / Q2) of the supply amount of reforming air (Q1) to the supply amount of ammonia gas (Q2) is within a predetermined range, and / or so that the temperature of the high-temperature gas generated by the combustion of the mixed gas of ammonia gas and reforming air is within a predetermined temperature range. This allows for appropriate control of the combustion reaction of the mixed gas of ammonia gas and reforming air. As a result, the combustion reaction and reforming reaction of ammonia gas are carried out in a suitable balance, and a hydrogen-containing reformed gas is stably produced in the reformer, and the produced reformed gas is burned in the combustor. Therefore, reformed gas can be stably produced without the need to separately provide heating means such as heaters, thereby enabling stable combustion.

[0010] In the ammonia reforming combustion system according to the present invention, It is preferable that the reformed gas is introduced from the reformer to the combustor in such a way as to maintain the temperature of the reformed gas.

[0011] With this ammonia reforming combustion system configuration, the thermal energy of the reformed gas is utilized in the combustor without loss, thus improving the calorific value in the combustor.

[0012] In the ammonia reforming combustion system according to the present invention, Preferably, the reforming air supply amount control means further controls the supply amount (Q1) of the reforming air based on the oxygen concentration in the reformed gas.

[0013] With this ammonia reforming combustion system configuration, the supply amount of reforming air (Q1) is controlled based on the oxygen concentration in the reformed gas, thereby preventing excessive combustion of ammonia gas in the reformer.

[0014] In the ammonia reforming combustion system according to the present invention, Preferably, the system further includes a mixed gas supply amount control means that controls the supply amount (Q1 + Q2) of the mixed gas based on the oxygen concentration in the reformed gas.

[0015] In this ammonia reforming combustion system configuration, the supply amount of the mixed gas (Q1 + Q2) of ammonia gas and reforming air is controlled based on the oxygen concentration in the reformed gas, thereby preventing excessive combustion of ammonia gas in the reformer. Furthermore, by ultimately setting the supply amount of the mixed gas (Q1 + Q2) to 0 and stopping the supply of the mixed gas to the reformer, damage to the reformer can be prevented.

[0016] In the ammonia reforming combustion system according to the present invention, It is preferable to further provide a combustion air supply amount control means for controlling the amount of combustion air supplied (Q3) so that the ratio (Q3 / Q2) of the amount of ammonia gas supplied (Q3) is within a predetermined range.

[0017] In this ammonia reforming combustion system configuration, the amount of combustion air supplied (Q3) is controlled so that the ratio (Q3 / Q2) of the amount of combustion air supplied (Q3) to the amount of ammonia gas supplied (Q2) is within a predetermined range, thereby enabling stable combustion in the combustor.

[0018] In the ammonia reforming combustion system according to the present invention, When starting up the operation of a combustion furnace, it is preferable to utilize the heat of combustion generated by the combustor.

[0019] This ammonia reforming combustion system allows for the use of combustion heat generated in the combustor, instead of fossil fuels such as city gas and kerosene, which were conventionally used as fuel for starting up the combustion furnace. This makes it possible to address the urgent issue of decarbonization in recent years.

[0020] Next, the characteristic configuration of the ammonia reforming combustion method according to the present invention for solving the above problems is as follows: An ammonia reforming combustion method including an ammonia gas supply step for supplying ammonia gas, a reforming air supply step for supplying reforming air, and a combustion air supply step for supplying combustion air, a reformed gas generation step of reforming the ammonia gas by using the heat of high-temperature gas generated by combustion of a mixed gas of the ammonia gas supplied in the ammonia gas supply step and the reforming air supplied in the reforming air supply step to generate a reformed gas containing hydrogen, a combustion step of combusting a mixed gas of the reformed gas generated in the reformed gas generation step and the combustion air supplied in the combustion air supply step, a reforming air supply amount control step of controlling the supply amount (Q1) of the reforming air so that the ratio (Q1 / Q2) of the supply amount (Q1) of the reforming air to the supply amount (Q2) of the ammonia gas is within a predetermined range in the reforming air supply step and / or so that the temperature of the high-temperature gas is within a predetermined temperature range in the reformed gas generation step, which includes the above.

[0021] According to the ammonia reforming combustion method of this configuration, the supply amount (Q1) of the reforming air is controlled so that the ratio (Q1 / Q2) of the supply amount (Q1) of the reforming air to the supply amount (Q2) of the ammonia gas is within a predetermined range and / or so that the temperature of the high-temperature gas generated by combustion of the mixed gas of the ammonia gas and the reforming air is within a predetermined temperature range. As a result, the combustion reaction of the mixed gas of the ammonia gas and the reforming air can be appropriately controlled. As a result, the combustion reaction and the reforming reaction of the ammonia gas are carried out in an appropriate balance, a reformed gas containing hydrogen is stably generated in the reformed gas generation step, and the generated reformed gas is combusted in the combustion step. Therefore, the reformed gas can be stably generated without separately performing a heating step using a heater or the like, and stable combustion can be achieved thereby.

Brief Description of the Drawings

[0022] [Figure 1]Figure 1 is a block diagram showing the schematic configuration of an ammonia reforming combustion system according to one embodiment of the present invention. [Figure 2] Figure 2 is a flowchart showing the processing steps for each process in an ammonia reforming combustion method according to one embodiment of the present invention. [Figure 3] Figure 3 is a flowchart showing the processing steps for the gas information acquisition process and the reforming air supply amount control process. [Figure 4] Figure 4 is a flowchart showing the processing steps for the gas information acquisition process and the combustion air supply amount control process. [Modes for carrying out the invention]

[0023] The present invention will be described below with reference to the drawings. However, the present invention is not intended to be limited to the embodiments and configurations described below or shown in the drawings.

[0024] [Ammonia reforming combustion system] Figure 1 is a block diagram showing the schematic configuration of an ammonia reforming combustion system 1 according to one embodiment of the present invention. As shown in Figure 1, the ammonia reforming combustion system 1 includes an ammonia gas supply device 3, a reformer 5, a combustor 7, a reforming air supply device 11, a combustion air supply device 13, and a control device 15.

[0025] <Ammonia gas supply system> As the ammonia gas supply device 3, for example, one can be configured with an ammonia tank and a vaporizer. The ammonia tank stores ammonia, which is the fuel, in a liquid state. The vaporizer vaporizes the liquid ammonia stored in the ammonia tank to produce ammonia gas, which is the fuel gas.

[0026] The ammonia gas supply device 3 and the reformer 5 are connected by an ammonia gas supply pipe 20. An upstream flow control valve 21 and a downstream flow control valve 23 are installed in the ammonia gas supply pipe 20 in that order from the upstream side to the downstream side of the ammonia gas flow.

[0027] <modifier> The reformer 5 is constructed by incorporating a composite catalyst 30 within a casing. The composite catalyst 30 combines a combustion catalyst 31 that burns ammonia (4NH3 + 3O2 → 2N2 + 6H2O) and a reforming catalyst 33 that is positioned downstream of the combustion catalyst 31 in the mixed gas flow and decomposes ammonia into hydrogen and nitrogen (2NH3 → N2 + 3H2). As the composite catalyst 30, known composite catalysts disclosed in, for example, Japanese Patent Publication No. 2010-215457, Japanese Patent Publication No. 2018-1095, Japanese Patent Publication No. 2018-1096, Japanese Patent Publication No. 2021-130100, etc., can be used. In the reformer 5, the heat of the high-temperature gas generated by the combustion of a mixed gas of ammonia gas supplied from the ammonia gas supply device 3 and reforming air supplied from the reforming air supply device 11 is used to reform the ammonia gas and produce a reformed gas containing hydrogen.

[0028] The reformer 5 and the combustor 7 are connected by a reformed gas supply pipe 40. The reformed gas supply pipe 40 is a relatively short straight pipe designed to directly introduce the reformed gas from the reformer 5 to the combustor 7 without cooling it, and an insulating material 41 is attached to its outer surface. In this way, the reformed gas from the reformer 5 is introduced to the combustor 7 while maintaining the temperature of the reformed gas, which is relatively high (around 500-600°C) generated in the reformer 5. With this configuration, the thermal energy of the reformed gas is utilized in the combustor 7 without loss, thereby increasing the heat output in the combustor 7.

[0029] <Combustion device> The combustor 7 burns a mixture of the reformed gas produced by the reformer 5 and the combustion air supplied from the combustion air supply device 13, generating high-temperature (approximately 1500°C) combustion exhaust gas necessary to bring a waste incinerator (combustion furnace), which has been shut down for periodic inspections or the like, to a predetermined combustion state when starting up.

[0030] <Air supply device for modification> The reformed air supply device 11 includes a reformed air blower 51 that forcibly sends out the incoming outside air (atmosphere) as reformed air, and a reformed air supply pipe 53 for supplying the reformed air sent out from the reformed air blower 51 to the reformer 5. The reformed air blower 51 mainly consists of a blower body 55, a motor 57 connected to the blower body 55, and an inverter 59 that controls the rotational speed of the motor 57. In the reformed air supply pipe 53, the upstream end of the reformed air flow is connected to the air outlet of the reformed air blower 51, and the downstream end of the reformed air flow is connected in communication with the portion of the ammonia gas supply pipe 20 between the upstream flow control valve 21 and the downstream flow control valve 23. In the air conditioning supply device 11, the amount of air supplied by the air conditioning blower 51, i.e., the amount of air conditioning supplied (Q1), is controlled by a control signal sent from the control device 15, more specifically from the blower control unit 82 (described later), to the inverter 59. The motor 57 is equipped with a tachometer 60 for measuring rotational speed, and the measurement signal from the tachometer 60 is sent to the control device 15. The blower control unit 82 (described later) compares the measured value measured by the tachometer 60 with a target value and sends a control signal to the inverter 59 according to the difference between the measured value and the target value, thereby controlling the measured value to match the target value.

[0031] <Combustion air supply system> The combustion air supply device 13 includes a combustion air fan 71 that forcibly sends out outside air (atmosphere) that has been taken in, a combustion air supply pipe 73 for supplying the combustion air sent out from the combustion air fan 71 to the combustor 7, and a flow rate adjustment damper 80 interposed in the combustion air supply pipe 73. The combustion air fan 71 mainly consists of a fan body 75 and a motor 77 connected to the fan body 75, and is configured to send out a predetermined amount of air while keeping the rotation speed of the motor 77 constant by a control signal sent to the motor 77 from the control device 15, more specifically from the fan control unit 83 which will be described later. In the combustion air supply pipe 73, the upstream end of the combustion air flow is connected to the air outlet of the combustion air fan 71, and the downstream end of the combustion air flow is connected to the combustor 7. In the combustion air supply device 13, the amount of air blown by the combustion air fan 71, i.e., the amount of combustion air supplied (Q3), is controlled by a control signal sent from the control device 15, more specifically from the damper control unit 84 (described later), to the flow rate adjustment damper 80.

[0032] The control device 15 is mainly composed of a computer and includes functional units such as a measurement unit 81, a blower control unit 82, a fan control unit 83, a damper control unit 84, and a valve control unit 85. The CPU executes a predetermined program, which enables the functions of each functional unit to be performed.

[0033] The ammonia reforming combustion system 1 further includes a gas flow meter 91, a gas pressure meter 92, a gas thermometer 93, and an oxygen concentration meter 94.

[0034] <Gas flow meter> The gas flow meter 91 is positioned to measure the flow rate of ammonia gas flowing through the pipe section between the location where the upstream flow control valve 21 is installed in the ammonia gas supply pipe 20 and the location where the downstream end of the reforming air supply pipe 53 is connected. The measurement signal from the gas flow meter 91 is sent to the control device 15 via the flow regulator 95. The flow regulator 95 compares the measured value measured by the gas flow meter 91 with a target value (indicated value) and sends a control signal corresponding to the difference between the measured value and the target value to the upstream flow control valve 21, thereby controlling the valve to match the measured value to the target value.

[0035] <Gas pressure gauge> The gas pressure gauge 92 is positioned to measure the pressure of ammonia gas flowing through the pipe section between the location where the gas flow meter 91 is installed in the ammonia gas supply pipe 20 and the location where the downstream end of the reforming air supply pipe 53 is connected. The measurement signal from the gas pressure gauge 92 is sent to the control device 15.

[0036] <Gas thermometer> The gas thermometer 93 is positioned to measure the temperature of the reformed gas flowing inside the upstream section of the reformed gas supply pipe 40, near the outlet of the reformer 5. The measurement signal from the gas thermometer 93 is sent to the control device 15.

[0037] <Oxygen concentration meter> The oxygen concentration meter 94 is positioned downstream of the gas thermometer 93, which is positioned to measure the oxygen concentration contained in the reformed gas flowing inside the reformed gas supply pipe 40. The measurement signal from the oxygen concentration meter 94 is sent to the control device 15.

[0038] <Gas information, means of acquiring gas information> In the control device 15, the measurement unit 81 measures the flow rate of ammonia gas based on the measurement signal from the gas flow meter 91. The measurement unit 81 measures the pressure of ammonia gas based on the measurement signal from the gas pressure gauge 92. The measurement unit 81 measures the temperature of the reformed gas based on the measurement signal from the gas thermometer 93. The measurement unit 81 measures the concentration of oxygen contained in the reformed gas based on the measurement signal from the oxygen concentration meter 94. The above-mentioned flow rate and pressure of ammonia gas, as well as the temperature and oxygen concentration of the reformed gas, are information about the gas flowing through the gas path from the ammonia gas supply device 3 through the reformer 5 to the combustor 7. In this embodiment, the gas information acquisition means for acquiring gas information mainly consists of measurement means (gas flow meter 91, gas pressure gauge 92, gas thermometer 93 and oxygen concentration meter 94) and the measurement unit 81.

[0039] <Means for controlling the amount of air supplied for modification> Based on the measurement means (gas flow meter 91 and gas thermometer 93) and the gas information acquired by the measurement unit 81, the blower control unit 82 transmits a predetermined control signal to the inverter 59 of the reforming air blower 51 to control the airflow rate of the reforming air blower 51, i.e., the amount of reforming air supplied (Q1), so that the ratio (Q1 / Q2) of the amount of reforming air supplied to ammonia gas (Q2) is within a predetermined range, and / or the temperature of the high-temperature gas generated by the combustion of the mixed gas of ammonia gas and reforming air (measured by the gas thermometer 93 near the outlet of the reformer 5) is within a predetermined temperature range.

[0040] <Means for controlling the amount of combustion air supplied> The fan control unit 83 transmits a control signal to the motor 77 of the combustion air fan 71, controlling the motor 77 to maintain a constant rotational speed and deliver a predetermined airflow rate. Based on the gas information acquired by the measuring means (gas flow meter 91) and the measurement unit 81, the damper control unit 84 transmits a predetermined control signal to the flow rate adjustment damper 80 to control the opening degree of the flow rate adjustment damper 80, thereby controlling the amount of combustion air supplied (Q3), so that the ratio (Q3 / Q2) of the amount of combustion air supplied (Q3) to the amount of ammonia gas supplied (Q2) is within a predetermined range. In this embodiment, the combustion air supply amount control means that controls the amount of combustion air supplied (Q3) by the combustion air supply device 13 based on gas information mainly consists of the flow rate adjustment damper 80, the fan control unit 83, and the damper control unit 84.

[0041] [Ammonia Reforming Combustion Method] Figure 2 is a flowchart showing the processing steps for each stage in an ammonia reforming combustion method according to one embodiment of the present invention. In Figure 2, the symbol "S" represents a step (the same applies to Figures 3 and 4).

[0042] <Ammonia gas supply process, reforming air supply process: S1> In the ammonia reforming combustion system 1, ammonia gas is supplied to the reformer 5 via the ammonia gas supply pipe 20 by the ammonia gas supply device 3 (ammonia gas supply process), and at the same time, reforming air is supplied to the reformer 5 via the reforming air supply pipe 53 and the ammonia gas supply pipe 20 by the reforming air supply device 11 (reforming air supply process).

[0043] <Reformed gas generation process: S2> The reformer 5, through the action of the composite catalyst 30, utilizes the heat of the high-temperature gas generated by the combustion of a mixed gas of ammonia gas supplied from the ammonia gas supply device 3 and reforming air supplied from the reforming air supply device 11 to reform the ammonia gas and produce a reformed gas containing hydrogen.

[0044] <Reformed gas supply process, combustion air supply process: S3> The reformed gas produced by the reformer 5 is supplied to the combustor 7 via the reformed gas supply pipe 40 (reformed gas supply process), and the combustion air supplied by the combustion air supply device 13 is supplied to the combustor 7 via the combustion air supply pipe 73 (combustion air supply process).

[0045] <Combustion process (combustion exhaust gas generation process): S4> The combustor 7 burns a mixture of reformed gas produced by the reformer 5 and combustion air supplied by the combustion air supply device 13 to generate high-temperature (approximately 1500°C) combustion exhaust gas.

[0046] In the reforming air supply process of step S1 in the flowchart of Figure 2, if the amount of reforming air (Q1) supplied to the reformer 5 is large, the combustion of the mixed gas of ammonia gas and reforming air in the combustion catalyst 31 is promoted, and the temperature of the high-temperature gas generated by combustion rises. This promotes the reaction to reform the ammonia gas, but because the ammonia gas to be reformed is consumed by combustion, the amount of hydrogen in the reformed gas decreases as the amount of reformed ammonia gas decreases. On the other hand, if the amount of reforming air (Q1) supplied to the reformer 5 is small, the combustion of the mixed gas of ammonia gas and reforming air in the combustion catalyst 31 is suppressed, and the temperature of the high-temperature gas generated by combustion decreases. As a result, the reaction to reform the ammonia gas does not proceed sufficiently, and the hydrogen content in the reformed gas decreases. Thus, whether the amount of reforming air (Q1) is large or small, the hydrogen content in the reformed gas decreases. Therefore, the reforming air supply amount control process described below is performed.

[0047] <Gas information acquisition process, reforming air supply amount control process: S11~S14> Figure 3 is a flowchart showing the processing steps for the gas information acquisition process and the reforming air supply amount control process.

[0048] The measurement unit 81 receives measurement signals from each measurement means (gas flow meter 91, gas thermometer 93, and rotational speed meter 60) (S11). Based on the received measurement signals, the measurement unit 81 measures the flow rate of ammonia gas (amount of ammonia gas supplied (Q2)) using the gas flow meter 91 and / or the temperature of the reformed gas using the gas thermometer 93 (S12).

[0049] The blower control unit 82 outputs a control signal to the inverter 59 so that the ratio (Q1 / Q2) of the amount of reformed air supplied by the reformed air blower 51 (Q1) to the amount of ammonia gas supplied by the gas flow meter 91 (Q2) is within a predetermined range, and / or so that the temperature of the reformed gas measured by the gas thermometer 93 is within a predetermined temperature range, thereby controlling the rotational speed of the motor 57 of the reformed air blower 51 to control the amount of reformed air supplied (Q1) (S13~S14). For example, in this case, if the amount of reformed air supplied to completely combust the ammonia gas supplied at the supply amount (Q2) is set to "1.0", the rotational speed of the motor 57 of the reformed air blower 51 is controlled so that the amount of reformed air supplied (Q1) is 0.2~0.4, preferably 0.25~0.35.

[0050] Furthermore, past operating data has shown that if the ratio (Q1 / Q2) of the supply amount of reformed air (Q1) to the supply amount of ammonia gas (Q2) is controlled to be within a predetermined range, the temperature of the high-temperature gas generated by the combustion of the mixed gas of ammonia gas and reformed air will be within a predetermined temperature range. Therefore, controlling the supply amount of reformed air (Q1) so that the ratio (Q1 / Q2) is within a predetermined range and controlling the supply amount of reformed air (Q1) so that the temperature of the reformed gas measured by the gas thermometer 93 is within a predetermined temperature range are substantially the same control methods. However, the two control methods are mutually complementary, and it is preferable to perform both control methods.

[0051] In this way, the supply amount of reformed air (Q1) is controlled so that the ratio (Q1 / Q2) of the supply amount of reformed air (Q1) to the supply amount of ammonia gas (Q2) is within a predetermined range, and / or so that the temperature of the high-temperature gas generated by the combustion of the mixed gas of ammonia gas and reformed air is within a predetermined temperature range. This allows for appropriate control of the combustion reaction of the mixed gas of ammonia gas and reformed air. As a result, the combustion reaction and reforming reaction of ammonia gas are carried out in a suitable balance, and a hydrogen-containing reformed gas is stably produced in the reformer 5, and the produced reformed gas is burned in the combustor 7. Therefore, in the ammonia reforming combustion system 1, reformed gas can be stably produced without the need to separately provide heating means such as heaters (in the ammonia reforming combustion method, a separate heating process using heaters etc. is not required), thereby enabling stable combustion.

[0052] <Gas information acquisition process, combustion air supply amount control process: S21~S25> Figure 4 is a flowchart showing the processing steps for the gas information acquisition process and the combustion air supply amount control process.

[0053] The measurement unit 81 receives a measurement signal from the gas flow meter 91 (S21). Based on the received measurement signal, the measurement unit 81 measures the flow rate of ammonia gas (ammonia gas supply amount (Q2)) using the gas flow meter 91 (S22).

[0054] The fan control unit 83 transmits a control signal to the motor 77 of the combustion air fan 71 (S23) and controls the motor 77 to maintain a constant predetermined rotational speed and deliver a predetermined amount of air. The damper control unit 84 outputs a control signal to the flow control damper 80 so that the ratio (Q3 / Q2) of the amount of combustion air supplied by the combustion air fan 71 (Q3) to the amount of ammonia gas supplied (Q2) is within a predetermined range, and controls the opening of the flow control damper 80 to control the amount of combustion air supplied (Q3) (S24-S25). For example, if the amount of reformed air supplied to completely combust the ammonia gas supplied at the supply amount (Q2) is set to "1.0", the opening of the flow control damper 80 is controlled so that the amount of combustion air supplied (Q3) is between 1.0 and 2.0, preferably between 1.2 and 1.6.

[0055] In this way, the amount of combustion air supplied (Q3) is controlled so that the ratio (Q3 / Q2) of the amount of ammonia gas supplied (Q3) falls within a predetermined range, thereby enabling stable combustion in the combustor.

[0056] <Process for controlling the amount of reformed air supplied based on oxygen concentration> During startup and shutdown of the ammonia reforming combustion system 1, the combustion reaction in the combustion catalyst 31 of the reformer 5 may become excessive. Therefore, the measurement unit 81 receives a measurement signal from the oxygen concentration meter 94 and measures the oxygen concentration of the reformed gas using the oxygen concentration meter 94. The blower control unit 82 then sends a control signal to the inverter 59 so that the oxygen concentration of the reformed gas measured by the oxygen concentration meter 94 is within a predetermined range, and controls the rotational speed of the motor 57 of the reformed air blower 51 to control the supply amount (Q1) of reformed air. This prevents the combustion reaction in the combustion catalyst 31 of the reformer 5 from becoming excessive during startup and shutdown of the ammonia reforming combustion system 1.

[0057] <Process for controlling the amount of mixed gas supplied based on oxygen concentration> Another method to prevent excessive combustion in the combustion catalyst of the reformer 5 during startup and shutdown of the ammonia reforming combustion system 1 is to control the supply amount (Q1+Q2). Specifically, the valve control unit 85 transmits a control signal to the downstream flow control valve 23 so that the oxygen concentration of the reformed gas measured by the oxygen concentration meter 94 is within a predetermined range, and controls the valve opening of the downstream flow control valve 23 to control the supply amount (Q1+Q2) of the mixed gas of ammonia gas and reforming air. Ultimately, by setting the supply amount (Q1+Q2) of the mixed gas to 0 and stopping the supply of the mixed gas to the reformer 5, it is possible to reliably prevent excessive combustion in the combustion catalyst 31 of the reformer 5. In this embodiment, the mixed gas supply amount control means that controls the supply amount (Q1+Q2) of the mixed gas of ammonia gas and reforming air based on the oxygen concentration in the reformed gas is composed of the downstream flow control valve 23 and the valve control unit 85.

[0058] <Emergency shutdown due to abnormal pressure> In the ammonia reforming combustion system 1, the measurement unit 81 receives a measurement signal from the gas pressure gauge 92, and if the pressure of the mixed gas of ammonia gas and reforming air measured by the gas pressure gauge 92 shows an abnormal value, the valve control unit 85 controls the valve opening of the downstream flow control valve 23 to set the supply amount of the mixed gas (Q1 + Q2) to 0, thereby stopping the supply of the mixed gas to the reformer 5.

[0059] In the combustion exhaust gas generation process at step S4 of the flowchart in Figure 2, the combustion exhaust gas generated by combustion in the combustor 7 is introduced into a wind box located at the bottom of the post-combustion stoker in a stoker-type incinerator (combustion furnace) that incinerates general waste or industrial waste as the material to be burned. In this way, by utilizing the combustion heat generated in the combustor 7 during the start-up of the furnace, the combustion heat generated in the combustor 7 is used instead of fossil fuels such as city gas or kerosene that were conventionally used as fuel for starting up the furnace, thereby contributing to decarbonization, which is an urgent issue in recent years. Furthermore, the combustion heat generated in the combustor 7 can also be utilized during the start-up of a combustion furnace that burns biomass fuel or sewage sludge.

[0060] Although the ammonia reforming combustion system and ammonia reforming combustion method of the present invention have been described above based on one embodiment, the present invention is not limited to the configuration described in the above embodiment, and its configuration can be modified as appropriate without departing from the spirit of the invention. [Industrial applicability]

[0061] The ammonia reforming combustion system and ammonia reforming combustion method of the present invention can be used, for example, to burn materials during the startup of a combustion furnace or boiler. [Explanation of symbols]

[0062] 1. Ammonia reforming combustion system 3. Ammonia gas supply system 5. Modifier 7 Combustor 11. Air supply device for modification 13. Combustion air supply device 23 Downstream flow control valve (means for controlling the amount of mixed gas supplied) 59 Inverter (means for controlling the amount of air supplied for reforming) 80 Flow rate control damper (means for controlling the amount of combustion air supplied) 82 Blower control unit (means for controlling the amount of air supplied for modification) 83 Fan control unit (means for controlling the amount of combustion air supplied) 84 Damper control unit (means for controlling the amount of combustion air supplied) 85 Valve control unit (means for controlling the amount of mixed gas supplied)

Claims

1. An ammonia reforming combustion system comprising an ammonia gas supply device for supplying ammonia gas, a reforming air supply device for supplying reforming air, and a combustion air supply device for supplying combustion air, A reformer that uses the heat of a high-temperature gas generated by the combustion of a mixed gas of ammonia gas supplied by the ammonia gas supply device and reformed air supplied by the reformed air supply device to reform the ammonia gas and produce a reformed gas containing hydrogen, A combustor burns a mixture of reformed gas produced by the reformer and combustion air supplied by the combustion air supply device. When the amount of air supplied for the complete combustion of ammonia gas supplied at a supply amount (Q2) by the ammonia gas supply device is set to 1.0, the reforming air supply amount control means controls the reforming air supply amount (Q1) supplied by the reforming air supply device to be between 0.2 and 0.

4. An ammonia reforming combustion system equipped with the following features.

2. The ammonia reforming combustion system according to claim 1, wherein the reformed gas is introduced from the reformer to the combustor in such a way as to maintain the temperature of the reformed gas.

3. The ammonia reforming combustion system according to claim 1 or 2, wherein the reforming air supply amount control means further controls the supply amount (Q1) of the reforming air based on the oxygen concentration in the reformed gas.

4. The ammonia reforming combustion system according to claim 1 or 2, further comprising a mixed gas supply amount control means for controlling the supply amount (Q1 + Q2) of the mixed gas based on the oxygen concentration in the reformed gas.

5. The ammonia reforming combustion system according to claim 1 or 2, further comprising a combustion air supply amount control means for controlling the amount of combustion air supplied by the combustion air supply device so that the amount of combustion air supplied (Q3) is between 1.0 and 2.0 when the amount of air supplied when completely combusting the ammonia gas supplied by the ammonia gas supply device at a supply amount (Q2) is set to 1.

0.

6. The ammonia reforming combustion system according to claim 1 or 2, which utilizes the heat of combustion generated in the combustor during the startup of the combustion furnace.

7. An ammonia reforming combustion method comprising an ammonia gas supply step for supplying ammonia gas, a reforming air supply step for supplying reforming air, and a combustion air supply step for supplying combustion air, A reformed gas generation step that uses the heat of a high-temperature gas generated by the combustion of a mixed gas of ammonia gas supplied in the ammonia gas supply step and reformed air supplied in the reformed air supply step to reform the ammonia gas and produce a reformed gas containing hydrogen, A combustion step in which a mixed gas of the reformed gas produced in the reformed gas generation step and the combustion air supplied in the combustion air supply step is burned, When the amount of air supplied for the complete combustion of the ammonia gas supplied at a supply amount (Q2) in the ammonia gas supply process is set to 1.0, the reforming air supply amount control process controls the reforming air supply amount (Q1) supplied in the reforming air supply process so that the reforming air supply amount (Q1) is between 0.2 and 0.

4. A method of ammonia reforming combustion that includes this process.

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