Hydrogen production device and hydrogen production method

Abstract

A hydrogen producing device according to an aspect of the present invention is characterized by being provided with: a hydrogen producing mechanism which produces hydrogen gas from a raw material by using a catalyst; and an operation control circuit which inputs a parameter value as an index indicating a state of the catalyst, and variably controls the maximum operation load of the hydrogen producing mechanism according to the parameter value.

Description

[Technical field]

[0001] This application claims priority from JP2019-071495 (application number) filed in Japan on April 3, 2019. The contents of JP2019-071495 are incorporated herein by reference.

[0002] The present invention relates to a hydrogen production device and a hydrogen production method, and more particularly to a device and a method for producing hydrogen gas used in a hydrogen station that fills a fuel cell vehicle (FCV) that uses hydrogen gas as a power source with hydrogen gas. [Background technology]

[0003] In addition to conventional fuel oils such as gasoline, hydrogen fuel has been attracting attention in recent years as a clean energy source for automobiles. Accordingly, the development of FCVs that use hydrogen fuel as a power source is underway. Hydrogen stations for FCVs include hydrogen shipping centers and on-site hydrogen stations (hereinafter referred to as on-site STs), which serve as hydrogen production bases, and off-site hydrogen stations (hereinafter referred to as off-site STs), which receive and sell hydrogen from hydrogen production bases (hydrogen shipping centers, on-site STs, etc.). At hydrogen production bases for FCVs, for example, LPG (liquefied petroleum gas) is used as a raw material, and high-purity hydrogen is produced by a catalytic reaction in a hydrogen production device (see, for example, Patent Document 1).

[0004] The quality of hydrogen gas supplied to FCVs must comply with ISO International Standard 14687-2. The ISO International Standard specifies impurities that may be contained in various hydrogen production methods, derived from raw materials and air, that adversely affect the performance of the fuel cell stack of FCVs. Here, in hydrogen production equipment that produces hydrogen from hydrocarbon raw materials through catalytic reactions, in order to comply with such strict ISO International Standards, it was necessary to adjust the operating load to maintain the quality of hydrogen gas when the performance deterioration or physical deterioration of the catalyst occurred. However, in the past, when deterioration of the quality of hydrogen gas was recognized, the operator consulted with the person in charge of the hydrogen production equipment manufacturer, determined the operating load based on empirical rules, etc., and changed the operating load to operate the hydrogen production equipment at the hydrogen station. Therefore, the conventional adjustment method had a problem in that it took time and effort to determine the operating load and to actually operate the equipment. Therefore, it is necessary to find signs of deterioration of the catalyst performance or physical deterioration before the quality of hydrogen gas deteriorates beyond the quality standards such as ISO International Standards, and adjust the operating load in a timely manner. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2015-150486 A Summary of the Invention [Problem to be solved by the invention]

[0006] Therefore, one aspect of the present invention provides a hydrogen production device and method that can detect signs of catalyst performance degradation or physical deterioration before the quality of hydrogen gas deteriorates beyond quality standards such as ISO international standards, and adjust the operating load in a timely manner. [Means for solving the problem]

[0007] A hydrogen production device according to one embodiment of the present invention comprises: a hydrogen production mechanism for producing hydrogen gas from a raw material using a catalyst; It is an indicator of the performance deterioration and / or physical deterioration of the catalyst. Multiple a control circuit that variably controls a maximum operating load of the hydrogen production mechanism in accordance with a parameter value; a sensor for measuring values ​​of the plurality of parameters; Equipped with The above Multiple The parameter value is input to the operation control circuit or is received by the operation control circuit; the hydrogen production mechanism includes a reformer having a plurality of reforming tubes in which the catalyst is disposed, The sensor includes: a plurality of thermometers for measuring the temperatures of the respective reforming tubes; a first pressure gauge for measuring a pressure upstream of the reformer; A second pressure gauge for measuring a pressure downstream of the reformer; having the values ​​of the plurality of parameters are temperatures of the reforming tubes measured by the plurality of thermometers and pressures measured by the first pressure gauge and the second pressure gauge; The operation control circuit controls the maximum operating load to one of a plurality of load stages depending on a combination of a maximum value of a temperature difference among the temperatures of the plurality of reforming tubes and a pressure difference between the pressure measured by the first pressure gauge and the pressure measured by the second pressure gauge.

[0008] A method for producing hydrogen according to one embodiment of the present invention includes the steps of: producing hydrogen gas from a raw material using a catalyst by a hydrogen production mechanism; It is an indicator of the performance deterioration and / or physical deterioration of the catalyst. Multiple variably controlling a maximum operating load of the hydrogen production mechanism in accordance with a parameter value; The sensor Multiple Measuring a value of a parameter; Equipped with the hydrogen production mechanism includes a reformer having a plurality of reforming tubes in which the catalyst is disposed, The sensor includes: a plurality of thermometers for measuring the temperatures of the respective reforming tubes; a first pressure gauge for measuring a pressure upstream of the reformer; A second pressure gauge for measuring a pressure downstream of the reformer; having the values ​​of the plurality of parameters are temperatures of the reforming tubes measured by the plurality of thermometers and pressures measured by the first pressure gauge and the second pressure gauge; The maximum operating load is controlled to one of a plurality of load stages depending on a combination of the maximum value of the temperature difference among the temperatures of the plurality of reforming tubes and the pressure difference between the pressure measured by the first pressure gauge and the pressure measured by the second pressure gauge.

[0009] Another aspect of the hydrogen production device of the present invention is a hydrogen production mechanism for producing hydrogen gas from a raw material using a catalyst; The value of a parameter that indicates the state of the catalyst is input, and the maximum operating load of the hydrogen production mechanism is variably controlled according to the parameter value. Regulation The control circuit and Equipped with El .

[0010] The hydrogen production mechanism produces hydrogen gas by a steam reforming method using a reformer having a reforming tube equipped with a catalyst, control The circuit preferably receives the temperature of the reforming tube as a parameter and controls so as to reduce the maximum operating load when the temperature of the reforming tube exceeds a preset threshold value.

[0011] Alternatively, the hydrogen production mechanism produces hydrogen gas by a steam reforming method using a reformer having a plurality of reforming tubes equipped with a catalyst; control The circuit preferably receives the temperatures of the multiple reforming tubes as parameters and performs control so as to reduce the maximum operating load when a temperature difference between the multiple reforming tubes exceeds a preset threshold value.

[0012] Also , regulationIt is preferable that the control circuit inputs the pressure upstream of the reformer and the pressure downstream of the reformer as parameters, and controls so as to reduce the maximum operating load when the pressure difference between the upstream pressure and the downstream pressure exceeds a preset threshold value.

[0013] Also , regulation It is preferable that the control circuit inputs values ​​of a plurality of parameters which are indicative of the state of the catalyst, and controls the maximum operating load to one of a plurality of load stages according to a combination of the states of the plurality of parameters.

[0014] Also , regulation It is preferable that the control circuit performs control to change the maximum operating load at predetermined intervals.

[0015] Another aspect of the present invention is a method for producing hydrogen, comprising the steps of: producing hydrogen gas from a feedstock using a catalyst in a hydrogen production device; inputting a value of a parameter that is an index showing a state of the catalyst, and variably controlling a maximum operating load of the hydrogen production mechanism in accordance with the value of the parameter; Equipped with El . Effect of the Invention

[0016] According to one embodiment of the present invention, signs of catalyst performance deterioration or physical deterioration can be found before the quality of hydrogen gas deteriorates beyond quality standards such as ISO international standards, and the operating load can be adjusted in a timely manner. [Brief description of the drawings]

[0017] [Figure 1] 1 is a diagram showing an example of a configuration of a hydrogen production device according to an embodiment. [Diagram 2] FIG. 2 is a diagram for explaining an example of performance deterioration of a catalyst in the first embodiment. [Diagram 3] FIG. 2 is a diagram for explaining an example of physical deterioration of the catalyst in the first embodiment. [Figure 4] 2 is a configuration diagram showing an example of the internal configuration of a control circuit in the first embodiment. FIG. [Diagram 5] FIG. 2 is a flow chart showing an example of main steps of the hydrogen production method in the first embodiment. [Figure 6] FIG. 2 is a diagram showing an example of an operation schedule of the hydrogen production device in the first embodiment. [Figure 7] FIG. 4 is a diagram showing an example of the relationship between the operating load and the reforming tube temperature in the steam reforming reaction in the first embodiment. [Figure 8] FIG. 4 is a diagram for explaining temperature measurement of a reforming tube in the first embodiment. [Figure 9] FIG. 4 is a diagram showing an example of the relationship between the temperature difference, the number of times the hydrogen production device is used, and the operating load in the first embodiment. [Figure 10] FIG. 4 is a diagram showing an example of the relationship between the pressure difference, the number of times the hydrogen production device is used, and the operating load in the first embodiment. [Figure 11] FIG. 4 is a flow chart showing an example of main steps of a hydrogen production method in a modified example of the first embodiment. [Figure 12] FIG. 11 is a diagram showing another example of the operation schedule of the hydrogen production device in the modified example of the first embodiment. [Figure 13] FIG. 4 is a diagram showing another example of the operation schedule of the hydrogen production device in the first embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS EXAMPLES

[0018] FIG. 1 is an example of a configuration diagram showing the configuration of a hydrogen production device in an embodiment. In FIG. 1, a hydrogen production unit (HPU) 100 includes a control circuit 102 that controls the entire hydrogen production unit 100, and a hydrogen production mechanism 150. The hydrogen production mechanism 150 includes a flow control valve 106, a flow meter 108, a compressor 104, a steam reformer 200, a gas-liquid separator 208, and a pressure swing adsorption (PSA) device 209. A desulfurizer 202, a reformer 204, and a transformer 206 are arranged in the steam reformer 200. The hydrogen production unit 100 is arranged in a hydrogen production base (for example, a hydrogen shipping center or an on-site ST), and for example, the raw material gas in a tank 600 is passed through the desulfurizer 202, the reformer 204, the transformer 206, the gas-liquid separator 208, and the PSA device 209 in this order to produce high-purity hydrogen gas.

[0019] Hydrocarbon compounds can be used as raw materials. Specific examples of hydrocarbon compounds include chain-like saturated aliphatic hydrocarbons such as ethane, propane, butane, pentane, hexane, heptane, and octane, and their structural isomers; chain-like unsaturated aliphatic hydrocarbons such as ethylene, propylene, butene, pentene, hexene, heptene, and octane, and their structural isomers; cyclic hydrocarbons such as cyclopentane, cyclohexane, cycloheptane, and cyclooctane, and their structural isomers; aromatic hydrocarbons such as benzene, toluene, xylene, naphthalene, and biphenyl, and their compounds having substituents. Examples of hydrocarbon compounds that contain these compounds alone or as a mixture include city gas, natural gas, LPG (liquefied petroleum gas), naphtha, gasoline, kerosene, and diesel.

[0020] Furthermore, as the raw material, raw materials containing alcohols, ethers, biofuels, etc., which are hydrocarbon compounds containing a substituent containing a heteroatom, can also be used. Examples of alcohols include methanol and ethanol, examples of ethers include dimethyl ether, and examples of biofuels include biogas, bioethanol, biodiesel, and biojet.

[0021] In addition, the above-mentioned raw materials may contain hydrogen, water, carbon dioxide, carbon monoxide, nitrogen, etc. For example, when hydrodesulfurization is performed as a pretreatment of the raw material, the residual hydrogen used in the reaction may be used as it is without being separated. The example in Figure 1 shows a case where LPG is used as the raw material. The raw material may be either gas or liquid. In the case of a liquid, it is vaporized before being supplied.

[0022] A plurality of reforming tubes 22(a-n) are arranged in the reformer 204, and the temperature of each reforming tube 22(a-n) is measured individually by a corresponding thermometer 20 among a plurality of thermometers 20(a-n). Furthermore, a pressure P1 on the upstream side of the reformer 204 and a pressure P2 on the downstream side of the reformer 204 are measured by pressure gauges 10 and 12, respectively. In the example of FIG. 1, for example, the pressure gauge 10 measures the pressure P1 on the upstream side of the desulfurizer 202. The pressure gauge 12 measures the pressure P2 on the downstream side of the transformer 206.

[0023] The hydrogen production mechanism 150 produces hydrogen gas from a raw material using a catalyst. In other words, the hydrogen production mechanism 150 produces hydrogen gas by steam reforming using the reformer 204 having reforming tubes equipped with a catalyst. Specifically, it operates as follows. First, the raw material gas in the tank 600 is compressed by the compressor 104 and sent to the desulfurizer 202. In the desulfurizer 202, sulfur components in the raw material gas are removed (desulfurized) by a chemical reaction. The desulfurized raw material gas is sent to the reformer 204 together with high-temperature steam, and reformed gases such as hydrogen (H2) gas and carbon monoxide (CO) gas are generated by steam reforming using a catalyst arranged in each reforming tube 22. Next, the generated reformed gas is sent to the shift converter 206, where the carbon monoxide gas reacts with the steam (shift reaction) to further generate hydrogen gas. The generated gas is then sent to the PSA unit 209, where impurities in the gas are removed by pressure swing adsorption to produce high-purity hydrogen gas. The hydrogen gas produced by the hydrogen production unit 100 located in the hydrogen shipping center is pressurized in a pressure accumulator or a hydrogen trailer, and then shipped to the off-site ST. The hydrogen gas produced by the hydrogen production unit 100 located in the on-site ST is pressurized in an intermediate pressure accumulator, or pressurized in a high-pressure accumulator by a compressor, in preparation for filling into FCVs.

[0024] FIG. 2 is a diagram for explaining an example of the performance deterioration of the catalyst in the first embodiment. In FIG. 2, as described above, the catalysts 24(a-n) are arranged in the reforming tubes 22(a-n), respectively. For example, a nickel-based catalyst in which nickel is supported on a carrier such as alumina, or a precious metal-based catalyst using a precious metal such as ruthenium or rhodium, can be used as the catalyst 24. The inside of the reforming tube 22 is exposed to high temperatures, for example, 750 to 850°C. When the number of times of operation of the hydrogen production device 100 increases, as shown in FIG. 2, coking may occur on the surface of the catalyst 24. If coking occurs on the surface of the catalyst 24, this leads to clogging of the reforming tube 22. As a result, the gas passing through the reforming tube 22 decreases, and the amount of hydrogen gas produced decreases. In addition, the catalyst 24 may be deactivated due to the coking occurring on the surface of the catalyst 24. In this case, the amount of the catalyst 24 that can contribute to the steam reforming reaction decreases, and the performance of the catalyst deteriorates.

[0025] 3 is a diagram for explaining an example of physical deterioration of the catalyst in the first embodiment. When the hydrogen production device 100 is operated many times, pulverization occurs in the reforming tubes 22 due to contact between catalysts 24, as shown in FIG. 3. When physical deterioration such as pulverization occurs, the life of the catalyst 24 is shortened, leading to deterioration of the catalyst performance. In addition, as pulverization of the catalyst 24 progresses, it may lead to clogging of the reforming tubes 22.

[0026] When performance deterioration or physical deterioration of the catalyst 24 occurs, the steam reforming reaction slows down. As a result, steam reforming is insufficient and the steam is discharged from the reformer 204. Therefore, in the hydrogen production device 100, it is necessary to reduce the supply amount of the raw material introduced into the reformer 204 in accordance with the amount of the catalyst 24 that can contribute to the steam reforming reaction, in other words, to reduce the operating load. Here, in the first embodiment, the above-mentioned performance deterioration of the catalyst 24 and / or the pulverization (physical deterioration) state of the catalyst 24 is determined by monitoring the temperature of the reforming tube 22 and the pressure loss of the reformer 204 as parameters. This will be specifically described below.

[0027] Fig. 4 is a configuration diagram showing an example of the internal configuration of the control circuit in the first embodiment. In Fig. 4, the control circuit 102 includes a communication control unit 50, a memory 51, a receiving unit 53, a schedule creating unit 54, an operation control unit 56, a raw material flow rate control unit 58, a maximum operation load control unit 60, a parameter receiving unit 70, and storage devices 52 and 72 such as magnetic disk devices. The maximum operation load control unit 60 includes a temperature determination unit 61, a temperature difference calculation unit 62, a determination unit 63, a determination unit 64, a pressure difference calculation unit 65, a determination unit 66, a determination unit 67, an alarm output unit 68, a maximum operation load determination unit 69, a temperature determination unit 73, a determination unit 80, and a maximum operation load control processing unit 81. Each unit such as the receiving unit 53, the schedule creating unit 54, the operation control unit 56, the raw material flow rate control unit 58, the maximum operation load control unit 60, and the parameter receiving unit 70 includes a processing circuit, and the processing circuit includes an electric circuit, a computer, a processor, a circuit board, or a semiconductor device. Each unit may use a common processing circuit (the same processing circuit), or may use different processing circuits (separate processing circuits). Input data or calculation results required in the receiving unit 53, the schedule creating unit 54, the operation control unit 56, the raw material flow rate control unit 58, the maximum operation load control unit 60, and the parameter receiving unit 70 are stored in the memory 51 each time or as needed.

[0028] Fig. 5 is a flow chart showing an example of the main steps of the hydrogen production method in embodiment 1. In Fig. 5, the hydrogen production method in embodiment 1 carries out a series of steps including a hydrogen production amount acquisition step (S90), an operation schedule creation step (S92), a hydrogen production device operation step (S94), and a maximum operation load control step (S100). The maximum operating load control process (S100) carries out a series of internal processes, including a reforming tube temperature measurement process (S102), a determination process (S104), a determination process (S105), a maximum temperature difference calculation process (S106), a determination process (S108), a determination process (S109), a pressure measurement process (S112), a pressure difference calculation process (S116), a determination process (S118), a determination process (S119), an alarm output process (S120), a determination process (S122), and a maximum load change process (S124).

[0029] First, outside the hydrogen production device 100, the amount of hydrogen to be produced per day, for example, is determined based on predicted demand and the like.

[0030] In the hydrogen production volume acquisition step (S90), the receiving unit 53 receives information on the hydrogen production volume to be produced by the hydrogen production device 100 via the communication control unit 50. For example, information on the hydrogen production volume required tomorrow (the day after the reception date) is received. Alternatively, if the time has not yet passed since the hydrogen production device 100 started operating, information on the hydrogen production volume required today (the day of the reception date) may be received. Note that the information on the hydrogen production volume is not limited to information required the day after the reception date in the receiving unit 53 and information required on the day of the reception date, but may also be information required on a specified day.

[0031] In the operation schedule creation step (S92), the schedule creation unit 54 creates an operation schedule for the hydrogen production device 100 based on the received information on the amount of hydrogen production. For example, an operation schedule for tomorrow (the day after the date of reception) is created. Alternatively, if the time has not yet passed since the start of operation of the hydrogen production device 100, an operation schedule for today (the day of reception) is created. Note that the creation of an operation schedule is not limited to the day after the date of reception and the day of reception, but may be for a specified day.

[0032] FIG. 6 is a diagram showing an example of an operation schedule of the hydrogen production device in the first embodiment. In FIG. 6, the vertical axis indicates the operation load of the hydrogen production device 100. The horizontal axis indicates the time of the operation day. In the example of FIG. 6, the case where the operation of the hydrogen production device starts from 8 o'clock is shown. Since the operation load of the hydrogen production device directly affects the amount of hydrogen gas that can be produced, it is not desirable to unnecessarily lower the operation load. Therefore, it is required that the hydrogen production device can be operated at as high a load as possible. As a method for adjusting the operation load, conventionally, the operator consults with the person in charge of the hydrogen production device manufacturer, determines the operation load based on empirical rules, etc., and operates the hydrogen production device at the hydrogen station by changing the operation load. Therefore, there is a problem that the maximum operation load of the hydrogen production device is not necessarily adjusted to near the upper limit that can be operated based on the performance of the actual catalyst, etc. Therefore, in the first embodiment, the pressure difference (pressure loss) based on the pressure and the temperature parameters are used as indexes to adjust the maximum operation load so as not to unnecessarily lower the operation load while grasping the state of the catalyst 24 (so that the state of the catalyst 24 can be maintained closer to the upper limit that can be operated by estimating the state of the catalyst 24). Here, the maximum operating load refers to the operating load when the hydrogen production equipment is operating at rated capacity (100%).

[0033] The schedule creation unit 54 creates an operation schedule (1) on the assumption that the maximum operating load is 100% when no deterioration or the like of the catalyst 24 occurs (for example, when the catalyst 24 is unused). In the operation schedule (1), for example, the operation (warm-up operation (idling)) of the hydrogen production device 100 is started at 8:00 a.m. with an operating load of about 30%. Then, from the end of the idling (for example, at 8:30 a.m.), the operating load is gradually increased at a preset acceleration rate (for example, several % / min) until the operating load reaches 100%. The example of FIG. 6 shows, for example, a case in which operation (rated operation) is performed at an operating load of 100% from 11:00 to 13:00. Then, from 13:00, the operating load is reduced at a preset deceleration rate (for example, several % / min) until the idling load (operating load of about 30%) is reached, and idling is started (the idling state is maintained). Then, the operation of the hydrogen production device is ended (stopped) at the end of the idling (for example, at 16:00). In this case, the amount of hydrogen gas that can be produced corresponds to the area enclosed by the graph of the operation schedule (1) and the horizontal axis (the integral value of the graph). Here, the operating load may be increased or decreased at a preset acceleration or at a preset constant speed (for example, several % / min). An operating load of 100% indicates rated operation of the hydrogen production device 100, and indicates a case where the hydrogen production device 100 is operated in such a way that the maximum amount of hydrogen gas that can be normally produced is produced. For example, an operating load of 80% indicates a case where the hydrogen production device 100 is operated in such a way that 80% of the maximum amount of hydrogen gas that can be normally produced (the amount of hydrogen gas produced at an operating load of 100%) is produced. The data of the created operation schedule (schedule data) is stored in the storage device 52.

[0034] In the above example, the operation schedule is created within the hydrogen production device 100, but the present invention is not limited to this. The operation schedule of the hydrogen production device 100 may be created outside the hydrogen production device 100. In such a case, the receiving unit 53 receives data of the operation schedule created outside (schedule data) via the communication control unit 50 and stores it in the storage device 52.

[0035] 5, in the hydrogen production device operation step (S94), under the control of the operation control unit 56, the hydrogen production mechanism 150 in the hydrogen production device 100 reads out operation schedule data (schedule data) from the storage device 52 and produces hydrogen gas in accordance with the operation schedule. The operation in this case is as described above. Here, under the control of the operation control unit 56, the raw material flow rate control unit 58 controls the aperture of the flow rate adjustment valve 106 in accordance with the operating load to control the flow rate of the raw material introduced from the tank 600. The flow rate of the introduced raw material is measured by the flow meter 108 and is fed back to the raw material flow rate control unit 58 via the communication control unit 50.

[0036] FIG. 7 is a diagram showing an example of the relationship between the operating load and the reforming tube temperature in the steam reforming reaction in the first embodiment. In FIG. 7, the vertical axis indicates the operating load of the hydrogen production device 100, and the horizontal axis indicates the temperature of the reforming tube. There is an appropriate reforming tube temperature depending on the operating load. Such a relationship may be measured in advance by an experiment or the like. The appropriate reforming tube temperature when operating at 100% operating load is, for example, 750 to 850°C. When the catalyst 24 deteriorates, the temperature of the reforming tube 22 rises and may become higher than the appropriate temperature. Therefore, by monitoring the temperature of the reforming tube 22, the state of the catalyst 24 can be grasped (estimated). In addition, the reforming reaction in the reformer 204 is an endothermic reaction. Therefore, for example, when the catalyst 24 of some of the reforming tubes 22 is blocked due to deterioration and the reforming reaction does not proceed, the gas that could not flow into the reforming tube 22 flows into another reforming tube 22 and tries to react, so that the reforming reaction in the other reforming tube 22 proceeds excessively. Therefore, in an over-reacting reformer tube 22, heat is taken away by the endothermic reaction, and the temperature of the reformer tube 22 may drop below the appropriate temperature. Furthermore, in a temperature range outside the appropriate temperature, it becomes difficult to carry out a sufficient reaction, which leads to deterioration of the quality of the hydrogen gas. Therefore, if it is possible to detect an increase or decrease in the temperature of the reformer tube 22, the operating load can be reduced before the quality of the hydrogen gas deteriorates beyond a quality standard (e.g., the ISO international standard), thereby making it possible to maintain the quality of the hydrogen gas within that quality standard.

[0037] Furthermore, it becomes difficult for the powdered catalyst 24 shown in Fig. 3 to achieve a sufficient reaction. When the catalyst 24 is powdered, the gas flow path in the reformer tube 22 narrows and the conductance decreases, resulting in a pressure loss. Therefore, if the pressure loss in the reformer 204 can be detected, the operating load can be reduced before the quality of the hydrogen gas deteriorates beyond a quality standard (e.g., ISO international standard). Such a pressure loss can be obtained, for example, by measuring the pressure difference between the inlet and outlet of the reformer 204.

[0038] 5, in a maximum operation load control step (S100), a maximum operation load control unit 60 (an example of an operation control circuit) inputs a parameter value serving as an index indicating (estimating) the state of the catalyst 24, and variably controls the maximum operation load of the hydrogen production mechanism 150 in the hydrogen production device 100 according to the parameter value. To this end, the maximum operation load control unit 60 first inputs a parameter value serving as an index indicating the state of the catalyst 24, and determines the maximum operation load of the hydrogen production mechanism 150 according to the parameter value. Specifically, the maximum operation load control unit 60 inputs temperature information of the reforming tube 22 as one of the parameters serving as an index indicating (estimating) the state of the catalyst 24, and controls the maximum operation load to be lowered when the temperature of the reforming tube 22 exceeds (or falls below) a preset threshold temperature. Moreover, the maximum operating load control unit 60 inputs temperature information of the plurality of reforming tubes 22 as one of the parameters serving as an index indicating (estimating) the state of the catalyst 24, thereby controlling the maximum operating load to be lowered when the temperature difference ΔT of the plurality of reforming tubes 22 exceeds a preset change threshold value Tth2. Moreover, the maximum operating load control unit 60 inputs the pressure P1 on the upstream side of the reformer 204 and the pressure P2 on the downstream side of the reformer 204 as one of the parameters serving as an index indicating (estimating) the state of the catalyst 24, thereby controlling the maximum operating load to be lowered when the pressure difference ΔP between the upstream pressure and the downstream pressure exceeds a preset change threshold value Pth2. Specifically, the operation is as follows. In the maximum operating load control step (S100), a reforming tube temperature measurement step (S102) and a pressure measurement step (S112) are executed in parallel.

[0039] On the one hand, as the reforming tube temperature measurement step (S102), as one of the parameters serving as an index (estimating) indicating the state of the catalyst 24, each thermometer 20(a - n) measures the temperature of the corresponding reforming tube 22(a - n). The measured temperature is received by the parameter receiving unit 70 via the communication control unit 50 and stored in the storage device 72 in association with the measurement time (or reception time).

[0040] FIG. 8 is a diagram for explaining the temperature measurement of the reforming tubes in Embodiment 1. As shown in FIG. 8, thermometers 20(a - n) are respectively connected to each reforming tube 22(a - n), and the temperatures Ta - Tn of each reforming tube 22(a - n) are measured at regular intervals. For example, when 16 reforming tubes 22 are arranged, 16 temperature data are measured at regular intervals.

[0041] Next, in FIG. 5, as the determination step (S104), the temperature determination unit 61 reads the temperature data of each reforming tube 22(a - n) from the storage device 72, and for each reforming tube 22k (indicating one of the reforming tubes 22(a - n)), determines whether the temperature Tk of the reforming tube 22k is within the range of the low - temperature threshold temperature Tt11 and the high - temperature threshold temperature Tt21 (Tt11 < Tk < Tt21). If the temperature of any one of the reforming tubes 22(a - n) is outside the range of the low - temperature threshold temperature Tt11 and the high - temperature threshold temperature Tt21 (S104 NO), the process proceeds to the determination step (S105). If the temperatures of all the reforming tubes 22(a - n) are within the range of the low - temperature threshold temperature Tt11 and the high - temperature threshold temperature Tt21 (S104 YES), the process proceeds to the maximum temperature difference calculation step (S106). Here, the low - temperature threshold temperature Tt11 indicates the alarm threshold on the lower limit side of the reforming tube temperature, and an alarm is issued when the temperature of the reforming tube is lower than Tt11. The high - temperature threshold temperature Tt21 indicates the upper limit value of the reforming tube temperature and is the alarm threshold at which an alarm is issued when the temperature exceeds this value.

[0042] As a determination step (S105), the temperature determination unit 73 determines whether the temperature of the reforming tube 22k outside the range between the low-temperature threshold temperature Tt11 and the high-temperature threshold temperature Tt21 is within the range between the low-temperature lower limit temperature Tt12 (Tt12 < Tt11) and the high-temperature upper limit temperature Tt22 (Tt21 < Tt22) (Tt12 < Tk < Tt22). When the temperature of the reforming tube 22k is outside the range between the low-temperature lower limit temperature Tt12 and the high-temperature upper limit temperature Tt22 (S105 NO), the hydrogen production apparatus 100 is stopped as if the temperature has exceeded the change temperature. Specifically, in response to a command from the operation maximum load control unit 60, the operation control unit 56 stops the operation of the hydrogen production mechanism 150 in the hydrogen production apparatus 100. Here, the low-temperature lower limit temperature Tt12 indicates the shutdown threshold on the lower limit side of the reforming tube temperature, and when the temperature of the reforming tube drops below Tt12, the hydrogen production apparatus 100 stops. The high-temperature upper limit temperature Tt22 indicates the upper limit value of the reforming tube temperature, and when the temperature exceeds this value, the hydrogen production apparatus 100 stops. The change temperature is the temperature at which, when exceeded, the load of the hydrogen production apparatus is changed (lowered). When stopping the operation of the hydrogen production mechanism 150 in the hydrogen production apparatus 100, it is preferable to decelerate at the deceleration rate described above and stop after passing through the idling operation. Note that the hydrogen gas produced after the time point when the temperature is outside the range between the low-temperature lower limit temperature Tt12 and the high-temperature upper limit temperature Tt22 may be discarded through a vent line (not shown) to maintain the quality of the produced hydrogen gas. After stopping the operation of the hydrogen production mechanism 150 in the hydrogen production apparatus 100, the reforming catalyst 24 of the reforming tube 22k outside the range of Tt12 < Tk < Tt22 is replaced, and then the process proceeds to restart. When the temperature of the reforming tube 22k is outside the range between the low-temperature threshold temperature Tt11 and the high-temperature threshold temperature Tt21 and within the range between the low-temperature lower limit temperature Tt12 and the high-temperature upper limit temperature Tt22 (S105 YES), the process proceeds to the determination step (S122).

[0043] In the maximum temperature difference calculation step (S106), the temperature difference calculation unit 62 calculates the difference (temperature difference ΔT) between the maximum temperature and the minimum temperature among the temperatures of the multiple reforming tubes 22(a-n). When, for example, 16 reforming tubes 22 are arranged in the reformer 204, the temperature difference ΔT is calculated by subtracting the temperature Tmin of the reforming tube 22 having the lowest measured temperature from the temperature Tmax of the reforming tube 22 having the highest measured temperature among the 16 reforming tubes 22.

[0044] Next, in the determination step (S108), the determination unit 63 determines whether the calculated temperature difference ΔT is lower than an alarm threshold Tth1. Here, the alarm threshold Tth1 is a threshold value at which an alarm is issued when the temperature difference between the maximum temperature and the minimum temperature among several reforming tubes becomes larger than this value.

[0045] FIG. 9 is a diagram showing an example of the relationship between the temperature difference, the number of times the hydrogen production device is used, and the operating load in the first embodiment. In FIG. 9, the vertical axis shows the temperature difference ΔT. The horizontal axis shows the number of times the hydrogen production device 100 is used. In FIG. 9, the relationship is shown when the hydrogen production device 100 is operated at an operating load of, for example, 100%, 90%, 80%, 70%, and 60%, respectively. Such a relationship may be obtained in advance by an experiment or the like. For example, the result is shown when the hydrogen production device 100 is continuously operated at such an operating load for several hours (for example, 3 to 6 hours) per use. The temperature difference ΔT increases as the number of times the hydrogen production device is used increases, regardless of the operating load. Also, the greater the operating load, the earlier the temperature difference ΔT starts to increase. Therefore, the greater the operating load, the earlier the temperature difference ΔT reaches the warning threshold Tth1. In other words, the smaller the operating load, the more the number of times the hydrogen production device can be used before the temperature difference ΔT reaches the warning threshold Tth1. If the calculated temperature difference ΔT is lower than the warning threshold Tth1 (YES in S108), there is no problem in continuing operation at the current (at that time) maximum operating load. Therefore, the process returns to the reforming tube temperature measurement process (S102) and repeats the same processes. If the calculated temperature difference ΔT is not lower than the warning threshold Tth1 (NO in S108), the process proceeds to the determination process (S109).

[0046] In FIG. 5, in the judgment step (S109), the judgment unit 64 judges whether the calculated temperature difference ΔT is lower than the change threshold Tth2. The fact that the number of times the hydrogen production device is used before the temperature difference ΔT reaches the alarm threshold Tth1 can be increased is also true for the change threshold Tth2 of the temperature difference higher than the alarm threshold Tth1. Here, the change threshold Tth2 is a threshold that changes (reduces) the operating load of the hydrogen production device 100 when the temperature difference between the maximum temperature and the minimum temperature among several reformer tubes becomes larger than this value. If the calculated temperature difference ΔT is lower than the change threshold Tth2 (S109 YES), the process proceeds to the alarm output step (S120). If the calculated temperature difference ΔT is not lower than the change threshold Tth2 (S109 NO), the process proceeds to the judgment step (S122).

[0047] On the other hand, in parallel with the reformer tube temperature measurement step (S102), a pressure measurement step (S112) is performed. In the pressure measurement step (S112), the pressure gauges 10 and 12 measure the pressure P1 on the upstream side of the reformer 204 and the pressure P2 on the downstream side of the reformer 204 as one of the parameters serving as an index showing (estimating) the state of the catalyst 24. In the example of FIG. 1, for example, the pressure gauge 10 measures the pressure P1 on the upstream side of the desulfurizer 202, and the pressure gauge 12 measures the pressure P2 on the downstream side of the transformer 206. The measured pressures P1 and P2 are received by the parameter receiving unit 70 via the communication control unit 50 and stored in the storage device 72 in association with the measurement time (or reception time).

[0048] Next, in a pressure difference calculation step (S116), the pressure difference calculation unit 65 subtracts the pressure P2 on the downstream side of the reformer 204 from the pressure P1 on the upstream side of the reformer 204 to calculate the pressure difference ΔP (differential pressure) between the pressure on the upstream side and the pressure on the downstream side of the reformer 204. Such pressure difference ΔP can be substantially regarded as a pressure loss in the reformer 204.

[0049] Next, in a determination step (S118), the determination unit 66 determines whether the calculated pressure difference ΔP is lower than an alarm threshold Pth1. The alarm threshold Pth1 is a threshold at which an alarm is issued if the pressure difference ΔP becomes larger than this threshold.

[0050] FIG. 10 is a diagram showing an example of the relationship between the pressure difference, the number of times the hydrogen production device is used, and the operating load in the first embodiment. In FIG. 10, the vertical axis shows the pressure difference ΔP. The horizontal axis shows the number of times the hydrogen production device 100 is used. In the example of FIG. 10, the relationship is shown when the hydrogen production device 100 is operated at an operating load of, for example, 100%, 90%, 80%, 70%, and 60%, respectively. Such a relationship may be obtained in advance by an experiment or the like. For example, the result is shown when the hydrogen production device 100 is continuously operated at such an operating load for several hours (for example, 3 to 6 hours) per use. In any case of the operating load, the pressure difference ΔP starts to rise as the number of times the hydrogen production device is used increases, and becomes higher as the number of times increases. In addition, the greater the operating load, the earlier the pressure difference ΔP starts to rise. Therefore, the greater the operating load, the earlier the pressure difference ΔP reaches the warning threshold value Pth1. Conversely, the smaller the operating load, the more times the hydrogen production device can be used before the pressure difference ΔP reaches the alarm threshold Pth1. If the calculated pressure difference ΔP is lower than the alarm threshold Pth1 (YES in S118), there is still no problem in continuing operation at the current (at that time) maximum operating load. Therefore, the process returns to the pressure measurement step (S112) and the same steps are repeated. If the calculated pressure difference ΔP is not lower than the alarm threshold Pth1 (NO in S118), the process proceeds to the determination step (S119).

[0051] Next, in the judgment step (S119), the judgment unit 67 judges whether the calculated pressure difference ΔP is lower than the change threshold Pth2. The fact that the number of times the hydrogen production device is used before the pressure difference ΔP reaches the alarm threshold Pth1 can be increased also applies to a change threshold Pth2 of the pressure difference higher than the alarm threshold Pth1. Here, the change threshold Pth2 is a threshold that changes (reduces) the operating load of the hydrogen production device 100 when the pressure difference ΔP becomes larger than this value. If the calculated pressure difference ΔP is lower than the change threshold Pth2 (S119 YES), the process proceeds to the alarm output step (S120). If the calculated pressure difference ΔP is not lower than the change threshold Pth2 (S119 NO), the process proceeds to the judgment step (S122).

[0052] In the alarm output step (S120), the alarm output unit 68 outputs an alarm when the temperature difference ΔT or the pressure difference ΔP exceeds an alarm threshold. For example, an alarm screen is displayed on a monitor (not shown) of the control circuit 102. This enables the operator to know that in the near future it will be necessary to change the maximum operating load to a lower value from the current state (at the time of receiving the alarm).

[0053] In the determination step (S122), the determination unit 80 determines whether the current maximum operating load is a preset limit maximum load (lower limit operating load value). The limit maximum load is set to, for example, 60%. If the current maximum operating load is the preset limit maximum load (YES in S122), the hydrogen production device 100 is stopped. If the current maximum operating load is not the preset limit maximum load (NO in S122), the process proceeds to a maximum load change step (S124).

[0054] Next, as a maximum load changing step (S124), the maximum operating load determination unit 69 determines the maximum operating load to a set value that is one rank lower than the current set value when, for example, the temperature difference ΔT between the multiple reforming tubes 22 exceeds a preset change threshold value Tth2. For example, if the current maximum operating load is 100% and the setting one rank lower is 90%, the maximum operating load is determined to be 90%. Then, the maximum operating load control processing unit 81 controls the maximum operating load to be lowered to the determined value (for example, 90%). Specifically, it controls the operation to be performed according to the operation schedule of the determined maximum operating load. To this end, the determined maximum operating load value and a command to lower the maximum operating load are output to the schedule creation unit 54. Then, the process returns to the operation schedule creation step (S92).

[0055] Then, in the operation schedule creation step (S92), the schedule creation unit 54 receives the value of the determined maximum operating load and a command to lower the maximum operating load, and re-creates the operation schedule with the determined maximum operating load. As shown in FIG. 6, for example, when the maximum operating load is changed (determined) during operation at 100% as shown in graph (1), the schedule from that point onward is re-created to graph (2) with the determined maximum operating load of 90%. Similarly, for example, when the maximum operating load is changed (determined) during operation at 90% as shown in graph (2), the schedule from that point onward is re-created to graph (3) with the determined maximum operating load of 80%. Similarly, for example, when the maximum operating load is changed (determined) during operation at 80% as shown in graph (3), the schedule from that point onward is re-created to graph (4) with the determined maximum operating load of 70%. Similarly, for example, when the maximum operating load is changed (determined) during operation at 70% as shown in graph (4), the schedule from that point onward is re-created to the graph (5) with the determined maximum operating load of 60%. The re-created operation schedule data is stored in the storage device 52 and updated, for example, overwritten.

[0056] Then, in the hydrogen production device operation step (S94), the operation control unit 56 operates the hydrogen production device 100 with the maximum operating load lowered according to the updated operation schedule. In other words, the operation control unit 56 controls the hydrogen production mechanism 150 in the hydrogen production device 100 with an operation schedule in which the maximum operating load is lowered when any one of the reforming tubes 22k among the reforming tubes 22(a-n) is outside the range between the threshold temperature Tt11 and the threshold temperature Tt21 and is within the range between the lower limit temperature Tt12 and the upper limit temperature Tt2. In addition, the operation control unit 56 controls the hydrogen production mechanism 150 in the hydrogen production device 100 with an operation schedule in which the maximum operating load is lowered when the temperature difference ΔT between the reforming tubes 22 exceeds a preset change threshold Tth2. In addition, the operation control unit 56 controls the hydrogen production mechanism 150 in the hydrogen production device 100 with an operation schedule in which the maximum operating load is lowered when the pressure difference ΔP between the upstream pressure and the downstream pressure exceeds a preset change threshold Pth2.

[0057] In the above example, when a cause for changing the maximum operating load occurs (when the change threshold is exceeded), the maximum operating load is reduced during operation of the hydrogen production device 100 on that day, but the present invention is not limited to this. For example, the device may be operated according to the original operation schedule on that day, and the maximum operating load may be reduced when creating the operation schedule for the next day.

[0058] In the above example, the value of each parameter is measured at a predetermined time (predetermined sampling time) during operation of the hydrogen production device 100, but this is not limited to the above. The maximum operating load control unit 60 may also suitably perform control to change the maximum operating load at predetermined intervals. For example, it is suitable to measure the value of each parameter every day, every other day, every third day, ..., or once a week, or once every few weeks, or once a month, or once every few months, and perform control to change the maximum operating load.

[0059] As described above, according to the first embodiment, before the quality of the hydrogen gas deteriorates beyond the quality standard, signs of performance deterioration or physical deterioration of the catalyst 24 can be found, and the operating load can be adjusted in a timely manner.

[0060] Fig. 11 is a flow chart showing an example of main steps of a hydrogen production method in a modification of the first embodiment. Fig. 11 is the same as Fig. 5 except that the internal steps of the maximum operation load control step (S100) are different. In Fig. 11, the maximum operation load control step (S100) performs a series of internal steps, including a reforming tube temperature measurement step (S202), a determination step (S204), a maximum temperature difference calculation step (S206), a determination step (S208), a determination step (S209), a determination step (S210), a pressure measurement step (S212), a pressure difference calculation step (S216), a determination step (S218), a determination step (S219), a determination step (S220), a maximum load determination step (S230), and a maximum load change step (S232).

[0061] The hydrogen production amount acquisition step (S90), the operation schedule creation step (S92), and the hydrogen production device operation step (S94) are as described above.

[0062] As a maximum operating load control step (S100), the maximum operating load control unit 60 (an example of an operating control circuit) inputs the values ​​of multiple parameters that serve as indicators of the state of the catalyst 24, and controls the maximum operating load to one of multiple load stages depending on the combination of the states of the multiple parameters.

[0063] In the reforming tube temperature measurement step (S202), each thermometer 20 (a-n) measures the temperature of the corresponding reforming tube 22 as one of the parameters serving as an index. The measured temperature is received by the parameter receiving unit 70 via the communication control unit 50, and is stored in the storage device 72 in association with the measurement time (or reception time).

[0064] Next, as the determination step (S204), the temperature determination unit 61 reads temperature data from the storage device 72, and for each reforming tube 22k, determines whether the temperature Tk of the reforming tube 22k is within the range of the lower limit temperature Tt12 on the low temperature side and the upper limit temperature Tt22 on the high temperature side (Tt12 < Tk < Tt22). If the temperature of any one of the reforming tubes 22 is outside the range of the lower limit temperature Tt12 on the low temperature side and the upper limit temperature Tt22 on the high temperature side (S204 NO), the hydrogen production apparatus 100 is stopped as described above. The stopping method is as described above.

[0065] Next, as the maximum temperature difference calculation step (S206), when the temperatures of all the reforming tubes 22 are within the range of the lower limit temperature Tt12 on the low temperature side and the upper limit temperature Tt22 on the high temperature side (S204 YES), the temperature difference calculation unit 62 calculates the temperature difference (maximum temperature difference ΔT) between the maximum temperature and the minimum temperature among the temperatures of the plurality of reforming tubes 22.

[0066] Next, as the determination step (S208), the determination unit 63 determines whether the calculated temperature difference ΔT is lower than the warning threshold value Tth1. If the calculated temperature difference ΔT is lower than the warning threshold value Tth1 (S208 YES), there is no problem in continuing the operation at the current maximum operating load. Therefore, the process returns to the reforming tube temperature measurement step (S202), and the same steps are repeated. Also, an identifier (for example, a1) indicating that the temperature difference ΔT is lower than the warning threshold value Tth1 is output to the maximum operating load determination unit 69. If the calculated temperature difference ΔT is not lower than the warning threshold value Tth1 (S208 NO), the process proceeds to the determination step (S209).

[0067] Next, as the determination step (S209), the determination unit 64 determines whether the calculated temperature difference ΔT is lower than the change threshold value Tth2. If the calculated temperature difference ΔT is lower than the change threshold value Tth2 (S209 YES), the process proceeds to the maximum load determination step (S230), and an identifier (for example, a2) indicating that the temperature difference ΔT is lower than the change threshold value Tth2 is output to the maximum operating load determination unit 69. If the temperature difference ΔT is not in a state lower than the change threshold value Tth2 (S209 NO), the process proceeds to the determination step (S210).

[0068] Next, in a determination step (S210), the determination unit 80 determines whether the current maximum operating load is a preset limit maximum load. The limit maximum load is set to, for example, 60%. If the current maximum operating load is the preset limit maximum load (YES in S210), the hydrogen production device 100 is stopped. If the current maximum operating load is not the preset limit maximum load (NO in S210), the process proceeds to a maximum load determination step (S230), and an identifier (e.g., a3) indicating that the temperature difference ΔT is not lower than the change threshold value Tth2 is output to the maximum operating load determination unit 69.

[0069] Next, in a pressure measurement step (S212), the pressure gauges 10, 12 measure the pressure P1 upstream of the reformer 204 and the pressure P2 downstream of the reformer 204 as one of the parameters serving as an index. As described above, in the example of FIG. 1, for example, the pressure gauge 10 measures the pressure P1 upstream of the desulfurizer 202. The pressure gauge 12 measures the pressure P2 downstream of the transformer 206. Each measured pressure is received by the parameter receiving unit 70 via the communication control unit 50 and stored in the storage device 72 in association with the measurement time (or reception time).

[0070] Next, as a pressure difference calculation step (S216), the pressure difference calculation unit 65 subtracts the pressure P2 downstream of the reformer 204 from the pressure P1 upstream of the reformer 204 to calculate the pressure difference ΔP (differential pressure) between the pressures upstream and downstream of the reformer 204.

[0071] In the determination step (S218), the determination unit 66 determines whether the calculated pressure difference ΔP is lower than the warning threshold Pth1. If the calculated pressure difference ΔP is lower than the warning threshold Pth1 (S218 YES), there is still no problem in continuing operation at the current maximum operating load. Therefore, the process returns to the pressure measurement step (S212) and repeats the same steps. In addition, an identifier (e.g., b1) indicating that the pressure difference ΔP is lower than the warning threshold Pth1 is output to the maximum operating load determination unit 69. If the calculated pressure difference ΔP is not lower than the warning threshold Pth1 (S218 NO), the process proceeds to the determination step (S219).

[0072] In the determination step (S219), the determination unit 67 determines whether the calculated pressure difference ΔP is lower than the change threshold value Pth2. If the calculated pressure difference ΔP is lower than the change threshold value Pth2 (S219 YES), the process proceeds to the maximum load determination step (S230) and outputs an identifier (e.g., b2) indicating that the pressure difference ΔP is lower than the change threshold value Pth2 to the maximum operating load determination unit 69. If the pressure difference ΔP is not lower than the change threshold value Pth2 (S219 NO), the process proceeds to the determination step (S220).

[0073] In the determination step (S220), the determination unit 80 determines whether the current maximum operating load is a preset limit maximum load. The limit maximum load is set to, for example, 60%. If the current maximum operating load is the preset limit maximum load (YES in S220), the hydrogen production device 100 is stopped. If the current maximum operating load is not the preset limit maximum load (NO in S220), the process proceeds to the maximum load determination step (S230), and an identifier (e.g., b3) indicating that the pressure difference ΔP is not lower than the change threshold value Pth2 is output to the maximum operating load determination unit 69.

[0074] In this manner, the maximum operating load determination unit 69 receives one of the identifiers a1 to a3 indicating a state related to the temperature difference Δ of the multiple reforming tubes 22, and one of the identifiers b1 to b3 indicating a state related to the pressure difference ΔP indicating the pressure loss of the reformer 204.

[0075] As a maximum load determination step (S230), the maximum operating load determination unit 69 determines which of the multiple load stages the maximum operating load should be, depending on a combination of a state related to the temperature difference ΔT of the multiple reforming tubes 22 and a state related to the pressure difference ΔP indicating the pressure loss of the reformer 204. For example, in the case of a combination of a state (a1) in which the temperature difference ΔT is smaller than the warning threshold Tth1 and a state (b1) in which the pressure difference ΔP is smaller than the warning threshold Pth1, the maximum operating load determination unit 69 determines the maximum operating load to be 100%. For example, in the case of a combination of a state (a1) in which the temperature difference ΔT is smaller than the warning threshold Tth1 and a state (b2) in which the pressure difference ΔP is not smaller than the warning threshold Pth1 but smaller than the change threshold Pth2, the maximum operating load determination unit 69 determines the maximum operating load to be 95%. For example, in the case of a combination of a state (a2) in which the temperature difference ΔT is not smaller than the warning threshold Tth1 but smaller than the change threshold Tth2, and a state (b1) in which the pressure difference ΔP is smaller than the warning threshold Pth1, the maximum operating load determination unit 69 determines the maximum operating load to be 90%. This shows a case in which the temperature difference ΔT is determined to have a higher priority as a factor for reducing the maximum operating load than the pressure difference ΔP. For example, in the case of a combination of a state (a2) in which the temperature difference ΔT is not smaller than the warning threshold Tth1 but smaller than the change threshold Tth2 and a state (b2) in which the pressure difference ΔP is not smaller than the warning threshold Pth1 but smaller than the change threshold Pth2, the maximum operating load determination unit 69 determines the maximum operating load to be 80%. For example, in the case of a combination of a state (a3) ​​in which the temperature difference ΔT is not smaller than the change threshold Tth2 and a state (b2) in which the pressure difference ΔP is not smaller than the warning threshold Pth1 but smaller than the change threshold Pth2, the maximum operating load determination unit 69 determines the maximum operating load to be 70%. For example, in the case of a combination of a state (a3) ​​in which the temperature difference ΔT is not smaller than the change threshold Tth2 and a state (b3) in which the pressure difference ΔP is not smaller than the change threshold Pth2, the maximum operating load determination unit 69 determines the maximum operating load to be 60%.

[0076] As a maximum load changing step (S232), the maximum operating load control processing unit 81 controls the maximum operating load to be lowered to a value determined from among a plurality of values ​​based on a combination of the states of a plurality of parameters. Specifically, the maximum operating load control processing unit 81 controls the operation to be performed according to the operation schedule of the determined maximum operating load. To this end, the determined maximum operating load value and a command to lower the maximum operating load are output to the schedule creation unit 54. Then, the process returns to the operation schedule creation step (S92).

[0077] Then, in an operation schedule creation step (S92), the schedule creation unit 54 receives the determined value of the maximum operation load and a command to lower the maximum operation load, and creates a new operation schedule with the determined maximum operation load.

[0078] FIG. 12 is a diagram showing another example of an operation schedule of a hydrogen production device in a modified example of the first embodiment. In FIG. 12, the vertical axis indicates the operation load of the hydrogen production device 100. The horizontal axis indicates the time of day of operation. In the example of FIG. 12, a case where the operation of the hydrogen production device starts at 8 o'clock is shown. Since the operation load of the hydrogen production device directly affects the amount of hydrogen gas that can be produced, it is not desirable to unnecessarily reduce the operation load. For this reason, it is required that the hydrogen production device be capable of operating at as high a load as possible. Therefore, in the modified example of the first embodiment, the parameters of pressure and temperature are used as indexes, and the maximum operating load is adjusted so as not to unnecessarily reduce the operation load while grasping the state of the catalyst 24 by the combination of the states of these parameters.

[0079] For the combination of identifiers a1 and b1, an operation schedule (A) is created in which the maximum operating load is 100%, assuming that no deterioration or the like of the catalyst 24 occurs. In the operation schedule (A), for example, idling of the hydrogen production device 100 is started at 8:00 in the morning with a load of about 30%. Then, from the end of the idling (for example, 8:30), the operating load is gradually increased to 100% at a preset acceleration. In the example of FIG. 12, for example, a case is shown in which operation is performed at a load of 100% from 11:00 to 13:00. Then, from 13:00, the operating load is reduced to the idling load at a preset deceleration rate, and idling is started. Then, at the end of the idling (for example, 16:00), the operation of the hydrogen production device is ended (stopped). In this case, an amount of hydrogen gas equivalent to the area surrounded by the graph of the operation schedule (A) and the horizontal axis (the integral value of the graph) can be produced. The created schedule data is stored in the storage device 52.

[0080] For the combination of identifiers a1 and b2, although it cannot be said that the catalyst 24 is deteriorating, etc., an operation schedule (B) is created in which the maximum operating load is switched from 100% to 95% midway through, to reduce the operating load slightly just in case.

[0081] For the combination of identifiers a2 and b1, it cannot be said that the catalyst 24 is deteriorating, but just to be on the safe side, an operation schedule (C) is created in which the maximum operating load is 90%, with the operating load being slightly reduced.

[0082] For the combination of identifiers a2 and b2, an operation schedule (D) is created in which the maximum operating load is 80%, as an alarm state in which deterioration of the catalyst 24 or the like has occurred.

[0083] For the combination of identifiers a3 and b2, an operation schedule (E) is created in which the maximum operating load is 70%, assuming that the temperature difference has progressed beyond the warning state in which deterioration of the catalyst 24 has occurred.

[0084] For the combination of identifiers a3 and b3, an operation schedule (F) is created in which the maximum operating load is 60%, assuming that both the temperature difference and the pressure difference have progressed beyond an alarm state in which deterioration of the catalyst 24 has occurred.

[0085] In the above example, the operation schedule is created within the hydrogen production device 100, but the present invention is not limited to this. The operation schedule of the hydrogen production device 100 may be created outside the hydrogen production device 100. In such a case, the receiving unit 53 receives the created schedule data via the communication control unit 50, and the created schedule data is stored in the storage device 52 and updated, for example by being overwritten.

[0086] Then, in the hydrogen production device operation step (S94), the operation control unit 56 operates the hydrogen production mechanism 150 with the maximum operating load lowered in accordance with the updated operation schedule. In other words, the operation control unit 56 controls the hydrogen production mechanism 150 with an operation schedule in which the maximum operating load is lowered to a maximum operating load determined from among multiple stages of maximum operating loads in accordance with a combination of the states of multiple parameters.

[0087] In the above example of the modification of the first embodiment, when a cause (each combination) for changing the maximum operating load occurs, the maximum operating load is reduced during the operation of the hydrogen production device 100 on that day, but the present invention is not limited to this. For example, it is also preferable to operate the device according to the original operation schedule on that day, and reduce the maximum operating load when creating the operation schedule for the next day.

[0088] In the above-mentioned example of the modification of the first embodiment, the values ​​of the parameters are measured constantly or at a predetermined sampling time during the operation of the hydrogen production device 100, but the present invention is not limited to this. It is also preferable that the maximum operating load control unit 60 performs control to change the maximum operating load at predetermined intervals. For example, it is also preferable to measure the values ​​of the parameters every day, every other day, every third day, ..., or once a week, or once every few weeks, or once a month, or once every few months, and perform control to change the maximum operating load.

[0089] As described above, according to the modified example of embodiment 1, before the quality of the hydrogen gas deteriorates, signs of performance deterioration or physical deterioration of the catalyst 24 can be found by combining the states of multiple parameters, and the operating load can be adjusted to the required stage in a timely manner.

[0090] FIG. 13 is a diagram showing another example of an operation schedule of the hydrogen production device in the first embodiment. In FIG. 13, the vertical axis indicates the operating load of the hydrogen production device 100. The horizontal axis indicates the time of the operation day. The example of FIG. 13 shows a case where idling continues at night, and the operating load is gradually increased to 100% load at a preset acceleration from, for example, 8 o'clock. Since idling is not required from 8 o'clock to the end of idling (for example, 8:30), the acceleration start time and deceleration start time are earlier than those in FIG. 6. The other contents are the same as those in FIG. 6. Here, the operating load may be increased or decreased at a preset acceleration or at a preset constant speed (for example, several % / min).

[0091] In the example of FIG. 13, the schedule creation unit 54 creates an operation schedule (1') on the assumption that the maximum operating load is 100% when the catalyst 24 is not degraded. In the operation schedule (1'), idling is continued at night, and the operating load is gradually increased from, for example, 8:00 a.m. to 100% load at a preset acceleration. In the example of FIG. 13, for example, a case is shown in which operation is performed at 100% load from about 10:30 to about 12:30. Then, from about 12:30, the operating load is reduced to the idling load at a preset deceleration rate, and idling is continued until the acceleration start time of the next day. In this case, an amount of hydrogen gas equivalent to the area surrounded by the graph of the operation schedule (1') and the horizontal axis (the integral value of the graph) can be produced. The hydrogen gas produced at night is stored in a pressure accumulator or the like. Alternatively, it may be discharged from a vent line (not shown). The created schedule data is stored in the storage device 52.

[0092] In the above example, the operation schedule is created within the hydrogen production device 100, but the present invention is not limited to this. The operation schedule of the hydrogen production device 100 may be created outside the hydrogen production device 100. In such a case, the receiving unit 53 receives the created schedule data via the communication control unit 50, and the created schedule data is stored in the storage device 52.

[0093] Then, when the determined value of the maximum operating load and the command to reduce the maximum operating load are received, in the operation schedule creation step (S92), the schedule creation unit 54 receives the determined value of the maximum operating load and the command to reduce the maximum operating load, and re-creates the operation schedule with the determined maximum operating load. As shown in FIG. 13, for example, when the maximum operating load is changed (determined) during operation at 100% as shown in graph (1'), the schedule from that point onward is re-created to graph (2') with the determined maximum operating load of 90%. Similarly, for example, when the maximum operating load is changed (determined) during operation at 90% as shown in graph (2'), the schedule from that point onward is re-created to graph (3') with the determined maximum operating load of 80%. Similarly, for example, when the maximum operating load is changed (determined) during operation at 80% as shown in graph (3'), the schedule from that point onward is re-created to graph (4') with the determined maximum operating load of 70%. Similarly, for example, when the maximum operating load is changed (determined) during operation at 70% as shown in graph (4'), the schedule from that point onward is re-created to graph (5') with the determined maximum operating load of 60%. The re-created schedule data is stored in the storage device 52 and updated, for example, overwritten. Other points are the same as those described above.

[0094] In addition, as with another example of the operating schedule in the modified example of embodiment 1 shown in FIG. 12, similar to FIG. 13, the hydrogen production device 100 may be configured to start operating in the morning of the day and continue idling overnight rather than shutting down when production of hydrogen gas for the day is completed.

[0095] The embodiments have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. In the example of FIG. 11, the determination step of whether the temperature of each reforming tube 22 is individually within the range of the threshold temperatures Tt11 and Tt21 is omitted, but it is also suitable to include this. For example, if the temperature tk of any one of the reforming tubes 22 is outside Tt11 < Tk < Tt21, it is also suitable to include it in the identifier a2.

[0096] Also, parts that are not directly necessary for the description of the present invention, such as the device configuration and control method, etc., have been omitted, but the required device configuration and control method can be appropriately selected and used.

[0097] In addition, all hydrogen production devices and hydrogen production methods that include the elements of the present invention and can be appropriately designed and modified by those skilled in the art are included in the scope of the present invention.

Industrial Applicability

[0098] Regarding the hydrogen production device and the hydrogen production method, for example, it can be used in an apparatus and method for producing hydrogen gas used in a hydrogen station that fills a fuel cell vehicle powered by hydrogen gas with hydrogen gas.

Explanation of Signs

[0099] 10, 12 Pressure gauge 20 Thermometer 22 Reforming tube 50 Communication control unit 51 Memory 52, 72 Storage device 53 Receiver 54 Schedule creation unit 56 Operation control unit 58 Raw material flow control unit 60 Operation maximum load control unit 61 Temperature determination unit 62 Temperature difference calculation unit 63 Determination unit 64 Determination unit 65 Pressure difference calculation unit 66 Determination unit 67 Judgment section 68 Alarm output section 69 Maximum operating load determination unit 70 Parameter receiver 73 Temperature judgment section 80 Judgment section 81 Maximum operating load control processing unit 100 Hydrogen production equipment 102 Control circuit 104 Compressor 106 Flow control valve 108 Flow meter 150 Hydrogen production mechanism 200 Steam reformer 202 Desulfurizer 204 Reformer 206 Transformer 208 Gas-liquid separator 209 PSA device

Claims

1. a hydrogen production mechanism for producing hydrogen gas from a raw material using a catalyst; an operation control circuit that variably controls a maximum operating load of the hydrogen production mechanism in accordance with values ​​of a plurality of parameters that are indicative of performance deterioration and / or physical deterioration of the catalyst; a sensor for measuring values ​​of the plurality of parameters; Equipped with The values ​​of the plurality of parameters are input to the operation control circuit or received by the operation control circuit; the hydrogen production mechanism includes a reformer having a plurality of reforming tubes in which the catalyst is disposed, The sensor includes: a plurality of thermometers for measuring the temperatures of the respective reforming tubes; a first pressure gauge for measuring a pressure upstream of the reformer; a second pressure gauge for measuring a pressure downstream of the reformer; having the values ​​of the plurality of parameters are temperatures of the reforming tubes measured by the plurality of thermometers and pressures measured by the first pressure gauge and the second pressure gauge; The operation control circuit controls the maximum operating load to one of a plurality of load stages depending on a combination of a maximum temperature difference between the temperatures of each of the plurality of reforming tubes and a pressure difference between the pressure measured by the first pressure gauge and the pressure measured by the second pressure gauge.

2. producing hydrogen gas from a raw material using a catalyst by a hydrogen production mechanism; variably controlling a maximum operating load of the hydrogen production mechanism in accordance with values ​​of a plurality of parameters that are indicative of performance deterioration and / or physical deterioration of the catalyst; measuring values ​​of the plurality of parameters with a sensor; Equipped with the hydrogen production mechanism includes a reformer having a plurality of reforming tubes in which the catalyst is disposed, The sensor includes: a plurality of thermometers for measuring the temperatures of the respective reforming tubes; a first pressure gauge for measuring a pressure upstream of the reformer; a second pressure gauge for measuring a pressure downstream of the reformer; having the values ​​of the plurality of parameters are temperatures of the reforming tubes measured by the plurality of thermometers and pressures measured by the first pressure gauge and the second pressure gauge; a hydrogen production method in which the maximum operating load is controlled to one of a plurality of load stages depending on a combination of a maximum value of a temperature difference among the temperatures of each of the plurality of reforming tubes and a pressure difference between the pressure measured by the first pressure gauge and the pressure measured by the second pressure gauge.

3. The hydrogen production device according to claim 1 , wherein the operation control circuit includes an operation schedule creation unit, and the operation schedule creation unit creates an operation schedule based on the maximum operating load.

4. The hydrogen production device according to claim 3 , wherein when the maximum operating load is changed, the operation schedule creation unit creates a new operation schedule from that point onward.

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