Gas flow path humidifier, hydrogen gas analysis system, gas flow path humidifier method, and hydrogen gas analysis method

Abstract

To provide a gas channel humidifier or the like that can humidify a gas in a channel without condensation.SOLUTION: A gas channel humidifier humidifies a channel in which a gas flows. The gas channel humidifier has a humidification channel in which the gas is humidified, a water tank that holds water in liquid form, and a heater that heats the water. The humidification channel is at least partially composed of perfluorosulfonated polytetrafluorostyrene, and the humidification channel is at least partially immersed in the water of the water tank.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a gas flow path humidifier, a hydrogen gas analysis system, a gas flow path humidifier method, and a hydrogen gas analysis method, and in particular to a gas flow path humidifier that humidifies a flow path through which gas flows. [Background technology]

[0002] In recent years, there has been an increasing need to provide high-quality hydrogen gas in order to put fuel cells into practical use. The inventors of the present application have developed fuel cell protection devices, temperature and humidity control devices, fluid transfer devices, and the like (Patent Documents 1 to 3).

[0003] Also, a gas chromatography device that continuously analyzes a sample gas by gas chromatography is known (Patent Document 4). Furthermore, a sensor cell that monitors various impurities in fuel hydrogen using a hydrogen pump type sensor cell is known (Patent Document 5). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2018-092786 A [Patent Document 2] Patent No. 6684491 [Patent Document 3] JP 2014-177892 A [Patent Document 4] JP 2002-181798 A [Patent Document 5] Patent No. 5597004 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the measurement of impurities in sample gas using a gas chromatography device generally requires a sample gas flow rate of about 3 L / min. In addition, a considerable amount of zero gas is required to wash the column after the measurement. In contrast, the measurement of impurities using a hydrogen pump-type sensor cell requires a smaller amount of sample gas.

[0006] However, hydrogen pump type sensor cells require humidification of 70% RH or more in order to take measurements, and become unusable if condensation occurs.

[0007] SUMMARY OF THE PRESENT DISCLOSURE An object of the present invention is to provide a gas flow path humidifier and the like that can humidify the gas in the flow path without causing condensation. [Means for solving the problem]

[0008] A first aspect of the present invention is a gas flow path humidifier that humidifies a flow path through which a gas flows, the gas flow path humidifier comprising a humidification flow path which is a flow path through which the gas flows and a water tank which holds liquid water, and a heater which heats the water, wherein at least a portion of the humidification flow path is made from perfluorosulfonated polytetrafluorostyrene, and at least a portion of the humidification flow path is immersed in the water of the water tank.

[0009] A second aspect of the present invention is the gas flow path humidifier of the first aspect, further comprising a water temperature measuring unit that measures the water temperature of the water tank and a heating control unit that controls the heater, wherein the heating control unit controls the heater so that the water is in the temperature range of 30°C to 45°C.

[0010] A third aspect of the present invention is a hydrogen gas analysis system having a hydrogen pump type sensor for measuring a CO impurity concentration of a sample gas which is hydrogen gas, the hydrogen pump type sensor having an electrolyte membrane which does not allow CO impurities to pass through, a flow path for sending the sample gas to the electrolyte membrane, a power source for applying a voltage to the electrolyte membrane, and a power source control unit for controlling the power source, and further comprising a voltmeter for measuring the voltage applied to the electrolyte membrane, a conversion unit for converting the voltage measured by the voltmeter into the CO impurity concentration, a humidification flow path which is a flow path for humidifying the sample gas, a water tank for holding liquid water, and a heater for heating the water, at least a portion of the humidification flow path is made of perfluorosulfonated polytetrafluorostyrene, and at least a portion of the humidification flow path is immersed in the water of the water tank.

[0011] A fourth aspect of the present invention is the hydrogen gas analysis system of the third aspect, further comprising a switching valve that switches between the supply of the sample gas to be analyzed and a zero gas not containing the CO impurity to the electrolyte membrane, and a switching valve control unit that controls the switching valve, wherein the switching valve control unit controls the switching valve to supply the sample gas to the electrolyte membrane, switch the switching valve to supply the zero gas for 120 seconds or less, and then switch the switching valve again to supply the sample gas.

[0012] A fifth aspect of the present invention is the hydrogen gas analysis system of the third or fourth aspect, further comprising a backup flow path that supplies a backup gas and is connected at a junction located midway along the flow path through which the sample gas is supplied to the electrolyte membrane, and a backup pressure control valve that controls the pressure of the backup gas supplied to the backup flow path, wherein the backup pressure control valve is capable of controlling the pressure of the backup gas at the junction to a pressure lower than the pressure of the sample gas.

[0013] A sixth aspect of the present invention is the hydrogen gas analysis system according to any one of the third to fifth aspects, further comprising a flow rate control unit that supplies the sample gas to the humidification channel at a flow rate of 200 mL / min or less.

[0014] A seventh aspect of the present invention is a gas flow path humidification method using a gas flow path humidifier that humidifies a flow path through which a gas flows, the gas flow path humidifier comprising a humidification flow path which is a flow path in which the gas is humidified, a water tank for holding liquid water, and a heater for heating the water, at least a portion of the humidification flow path is made from perfluorosulfonated polytetrafluorostyrene, and at least a portion of the humidification flow path is immersed in water in the water tank, the gas flow path humidification method comprising the steps of: a heating step in which the heater heats the water; and a humidification step in which the humidification flow path is humidified by being immersed in the water held in the water tank.

[0015] An eighth aspect of the present invention is the gas flow path humidification method of the seventh aspect, wherein the gas flow path humidifier further comprises a water temperature measuring unit that measures a water temperature of the water tank, and a heating control unit that controls the heater, and in the heating step, the heating control unit controls the heater so that the water is in a temperature range of 30°C to 45°C.

[0016] A ninth aspect of the present invention is a hydrogen gas analysis method using a hydrogen gas analysis system having a hydrogen pump type sensor and measuring a CO impurity concentration of a sample gas which is hydrogen gas, the hydrogen pump type sensor having an electrolyte membrane which does not allow CO impurities to pass through, a flow path for sending the sample gas to the electrolyte membrane, a power supply for applying a voltage to the electrolyte membrane, and a power supply control unit for controlling the power supply, the hydrogen gas analysis system having a voltmeter for measuring the voltage applied to the electrolyte membrane, a conversion unit for converting the voltage measured by the voltmeter into the CO impurity concentration, a humidification flow path which is a flow path for humidifying the sample gas, a water tank for holding liquid water, and a heating element for heating the water. and a heater, at least a portion of the humidification flow path is made of perfluorosulfonated polytetrafluorostyrene, and at least a portion of the humidification flow path is immersed in the water of the water tank, and the method includes a heating step of heating the water by the heater, a gas supply step of supplying the sample gas or a zero gas not containing the CO impurity to the humidification flow path, a humidification step of humidifying the humidification flow path in water held in the water tank, a measurement step of measuring a voltage applied to the electrolyte membrane by the voltmeter, and a conversion step of converting the voltage measured by the voltmeter into the CO impurity concentration by the conversion unit.

[0017] A tenth aspect of the present invention is the hydrogen gas analysis method of the ninth aspect, wherein the hydrogen gas analysis system further includes a switching valve that switches the supply of the sample gas to be analyzed and the zero gas to the electrolyte membrane, and a switching valve control unit that controls the switching valve, and in the gas supply step, the switching valve control unit controls the switching valve to provide a first sample gas supply step in which the sample gas is supplied to the electrolyte membrane, a zero gas supply step in which the zero gas is supplied for 120 seconds or less, and a second sample gas supply step in which the sample gas is supplied again.

[0018] An eleventh aspect of the present invention is the hydrogen gas analysis method of the ninth or tenth aspect, wherein the hydrogen gas analysis system further comprises a backup flow path that supplies a backup gas and is connected at a junction located midway along the flow path through which the sample gas is supplied to the electrolyte membrane, and a backup pressure control valve that controls the pressure of the backup gas supplied to the backup flow path, and the gas supply step further includes a backup gas pressure control step in which the backup pressure control valve controls the pressure of the backup gas at the junction to a pressure lower than the pressure of the sample gas.

[0019] A twelfth aspect of the present invention is a hydrogen gas analysis method according to any one of the ninth to eleventh aspects, wherein the hydrogen gas analysis system further includes a flow rate control unit that causes the sample gas to be supplied to the humidification flow path at a flow rate of 200 mL / min or less, and further includes a flow rate control step in which, in the gas supply step, the flow rate control unit supplies the sample gas or the zero gas to the flow path at a flow rate of 200 mL / min or less.

[0020] Furthermore, a thirteenth aspect of the present invention is a program for causing a computer to function as the heating control unit described in the eighth aspect, the power supply control unit described in the ninth aspect, the conversion unit described in the ninth aspect, the switching valve control unit described in the tenth aspect, and / or the flow rate control unit described in the twelfth aspect. Effect of the Invention

[0021] According to each aspect of the present invention, the temperature of the humidification flow path can be stably controlled, so that humidification can be easily performed while maintaining the temperature of the humidification flow path.

[0022] In addition, in conventional gas flow path humidifiers, there is a demand for rapid humidification due to the large humidification flow rate, and the humidification flow path is installed in a water vapor atmosphere rather than underwater. However, the inventors of the present application have developed a hydrogen gas measurement device that can measure impurity concentrations with a smaller amount of gas than conventional devices. During this development process, the inventors of the present application came to the idea that if the flow path is one that only allows very small amounts of gas to flow, it is possible to humidify sufficiently quickly even when immersed in water.

[0023] The inventors of the present application also noted that perfluorosulfonated polytetrafluorostyrene (Nafion (registered trademark)) has a good linearity of correlation between temperature and humidification amount in the temperature range of 30° C. to 45° C., and has high controllability.

[0024] According to the second or eighth aspect of the present invention, it is possible to maintain a high controllability state by the humidification flow path made of perfluorosulfonated polytetrafluorostyrene, and it becomes easy to humidify the humidification flow path precisely. Even at low temperatures (30 to 45°C), a humidity of 70 to 80% RH can be achieved with fine particles, and humidification without condensation becomes possible. As a result, it becomes possible to precisely control the humidity of the gas flowing through the flow path (70% ± 0.05% RH) and stabilize the CO concentration indication. In addition, since humidification is performed at a relatively low temperature, there is no need to make the entire gas flow path high temperature and high pressure, and it becomes easy to maintain safety.

[0025] In addition, the electrolyte membrane used in hydrogen pump-type sensors can measure with higher accuracy when the sample hydrogen gas has a high humidity, but becomes unusable once condensation occurs.

[0026] Therefore, according to the third or ninth aspect of the present invention, hydrogen gas which is highly humid but is humidified with fine particles and therefore less likely to condense is supplied to a hydrogen pump-type sensor as a sample gas, making it possible to analyze the hydrogen gas with high accuracy.

[0027] Furthermore, according to the fourth or tenth aspect of the present invention, it is possible to check the zero point more frequently than in an analysis method using a gas chromatography device that requires a large amount of gas to flow for a long time to clean the column. Switching the zero gas every 120 seconds also means checking the zero value every 120 seconds, and this is a measurement method with less zero drift. This makes it possible to perform continuous measurement of hydrogen gas, which is recommended in Europe, and enables high-precision analysis.

[0028] Furthermore, according to the fifth or eleventh aspect of the present invention, when the supply of sample gas to the hydrogen pump type sensor is reduced due to a power outage or the like, backup gas is continuously supplied to the hydrogen pump type sensor without interruption without relying on electrical control, so that no concentration measurement is missed. Therefore, even in the event of an unexpected event such as a power outage, it is not necessary for the system administrator to stop the operation of the hydrogen gas measuring device. Furthermore, it is possible to prevent the hydrogen pump type sensor from being damaged by being exposed to air.

[0029] Furthermore, according to the sixth or twelfth aspect of the present invention, when a small amount of sample gas is to be analyzed, it is possible to humidify the sample gas by the present invention. [Brief description of the drawings]

[0030] [Figure 1] 1 is a block diagram showing an overview of a hydrogen gas analysis system according to an embodiment of the present invention. [Diagram 2] 1 is a system configuration diagram showing an example of an outline of a hydrogen gas analysis system according to an embodiment of the present invention. [Diagram 3] 1 is a diagram showing an example of an outline of a hydrogen gas measuring device according to an embodiment of the present invention; [Figure 4] FIG. 2 is a flow chart showing an example of an outline of a measurement process flow in a hydrogen gas analysis method according to an embodiment of the present invention. [Diagram 5] FIG. 2 is a flow diagram showing an example of an operation flow of a hydrogen gas measuring device in a hydrogen gas analysis method according to an embodiment of the present invention. [Figure 6]4 is a graph showing an example of a change over time in the CO impurity concentration in hydrogen gas actually analyzed by the hydrogen gas analyzing system according to the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. However, the embodiment of the present invention is not limited to the contents described below. EXAMPLES

[0032] FIG. 1 is a block diagram showing an outline of a hydrogen gas analysis system 1 (an example of a "hydrogen gas analysis system" in the claims) according to an embodiment of the present invention. Referring to FIG. 1, the hydrogen gas analysis system 1 includes a hydrogen gas measurement device 3, a zero gas supply device 5, a calibration gas supply device 7, a flow path 9 (an example of a "flow path" in the claims), a valve 11, a switching valve 13 (an example of a "switching valve" in the claims), a conversion unit 15 (an example of a "conversion unit" in the claims), a display unit 17, a backup gas supply device 19, and a control unit 21. The hydrogen gas analysis system 1 measures and analyzes the CO impurity concentration of hydrogen gas (an example of a "gas" or "sample gas" in the claims) which is a sample gas. The hydrogen gas measurement device 3 measures the CO impurity concentration of hydrogen gas. The zero gas supply device 5 supplies the hydrogen gas measurement device 3 with zero gas (an example of a "zero gas" in the claims) whose CO impurity concentration can be evaluated as being sufficiently low enough to withstand the analysis of the sample gas. The calibration gas supplying device 7 supplies a calibration gas having a known CO impurity concentration to the hydrogen gas measuring device 3. The flow path 9 is a supply path for hydrogen gas such as sample gas, zero gas, and calibration gas. The valve 11 adjusts the amount and direction of hydrogen gas supply in the flow path 9. The switching valve 13 switches between supplying sample gas and zero gas to the hydrogen gas measuring device 3. The conversion unit 15 converts the voltage at the electrolyte membrane into a CO impurity concentration. The display unit 17 displays the CO impurity concentration of the hydrogen gas supplied to the electrolyte membrane. The backup gas supplying device 19 supplies a backup gas (an example of the "backup gas" in the claims) to the flow path 9. The control unit 21 controls various devices and the like.

[0033] The hydrogen gas measurement device 3 includes a humidification tank 23 (an example of a gas flow path humidifier in the present claims), a humidification flow path 25 (an example of a humidification flow path in the present claims), a distilled water tank 27, and a detection tank 29. The humidification tank includes a water tank 31 (an example of a water tank in the present claims), a heater 33 (an example of a heater in the present claims), and a water thermometer 35 (an example of a water temperature measuring unit in the present claims). The detection tank 29 includes a sensor cell 37 (an example of a hydrogen pump type sensor in the present claims), a power source 39 (an example of a power source in the present claims), a voltmeter 41 (an example of a voltmeter in the present claims), and a humidity sensor 43. The humidification tank 23 humidifies the humidification flow path 25. The humidification flow path 25 is a flow path in which the sample gas is humidified. The distilled water tank 27 holds distilled water to be supplied to the water tank 31. The detection tank 29 detects the concentration of CO (carbon monoxide) impurity contained in the sample gas. The water tank 31 holds water in which the humidification flow path 25 is immersed. The heater 33 heats the water held in the water tank 31. The sensor cell 37 detects CO contained in the sample gas. The power source 39 applies a voltage to the sensor cell 37. The voltmeter 41 measures the voltage applied to the sensor cell 37. The humidity sensor 43 measures the humidity in the detection tank 29.

[0034] The zero gas supply device 5 has a zero gas flow path 45 and a zero gas filter 47. The zero gas flow path 45 is a flow path branched from a zero gas flow path branch point 51 downstream of the check valve 49 of the flow path 9 to the hydrogen gas measuring device 3. For the sake of distinction, the flow path from the zero gas flow path branch point 51 to the hydrogen gas measuring device 3 in the flow path 9 through which the sample gas flows is referred to as a sample gas flow path 53. The zero gas filter 47 is installed in the zero gas flow path 45 and is a filter that removes CO from the hydrogen gas to a level that is sufficiently negligible compared to the sample gas. The hydrogen gas flowing in the zero gas flow path 45 passes through the zero gas filter 47 and becomes zero gas that does not contain CO, and is supplied to the hydrogen gas measuring device 3.

[0035] The calibration gas supply device 7 has a calibration gas cylinder 55 and a calibration gas flow path 57. The calibration gas cylinder 55 has a standard gas with a known CO impurity concentration. For example, in this embodiment, the calibration gas cylinder 55 has 10 L of standard gas containing a CO impurity concentration of 219 ppb. The calibration gas flow path 57 supplies calibration gas to the hydrogen gas measurement device 3. Here, the calibration gas flow path 57 has a diluter that mixes the sample gas and the standard gas at a predetermined ratio, so that it is possible to supply a calibration gas of 219 ppb or less to the hydrogen gas measurement device 3. By calibrating the hydrogen gas measurement device 3 periodically, preferably every day, it becomes easy to suppress zero drift to the 1 ppb level even if impurities adhere to the platinum electrode of the sensor cell 37.

[0036] The backup gas supply device 19 has a backup cylinder 59, a backup pressure control valve 61 (an example of the "backup pressure control valve" in the claims), and a backup flow path 63 (an example of the "backup flow path" in the claims). The backup cylinder 59 has hydrogen gas that does not contain CO impurities as a backup gas. The backup pressure control valve 61 controls the pressure at which the backup gas is supplied to the backup flow path 63. The backup flow path 63 is connected to the flow path 9 at a junction 65 (an example of the "junction" in the claims) to supply the backup gas to the flow path 9. When the supply of sample gas to the sensor cell 37 of the hydrogen gas measuring device 3 is reduced due to a power outage or the like, the backup gas is continuously supplied to the sensor cell 37 without interruption without relying on electrical control, so that no missing concentration measurements are generated. Therefore, even in an unexpected event such as a power outage, it is not necessary for the system administrator to stop the operation of the hydrogen gas measuring device 3. Furthermore, it is possible to prevent the electrode element of the sensor cell 37 from being exposed to air and damaged.

[0037] The control unit 21 has a valve control unit 67, a switching valve control unit 69 (an example of the "switching valve control unit" in the claims), a heating control unit 71 (an example of the "heating control unit" in the claims), a flow rate control unit 73 (an example of the "flow rate control unit" in the claims), a power supply control unit 75 (an example of the "power supply control unit" in the claims), and a display control unit 77. The valve control unit 67 controls the opening and closing of various valves in the hydrogen gas analysis system 1. The switching valve control unit 69 controls the switching valve 13 among the valves. The heating control unit 71 controls the heater 33. The flow rate control unit 73 controls the flow rate of hydrogen gas flowing through the flow path 9. The power supply control unit 75 controls the power supply 39. The display control unit 77 controls the display unit 17.

[0038] Next, the configuration of the hydrogen gas analysis system 1 of this embodiment will be described. FIG. 2 is a system configuration diagram showing an example of an outline of the hydrogen gas analysis system 1 according to the embodiment of the present invention. Referring to FIG. 2, hydrogen gas produced by a hydrogen production device 101 is supplied to a compressor 103 at 0.8 MPa. Thereafter, the hydrogen gas is supplied to a flow path 9 of the hydrogen gas analysis system 1 at 0.2 MPa via an accumulator 105, a dispenser 107, and a valve 109. A backup flow path 63 is connected to the flow path 9 at a junction 65 located between a check valve 111 and a check valve 113 installed in the flow path 9. A check valve 113 is also installed in the backup flow path 63 between the junction 65 and a backup cylinder 59. The capacity of the backup cylinder 59 is 7 m 3 It is.

[0039] Here, the pressure of the backup gas supplied from backup flow path 63 is lower than the pressure of hydrogen gas flowing through flow path 9 at junction 65, and is controlled to, for example, 0.15 MPa. Therefore, while hydrogen gas is being normally supplied to flow path 9, backup gas is not supplied to flow path 9 from junction 65. On the other hand, if the pressure of the hydrogen gas supplied to flow path 9 drops below 0.15 MPa due to a power outage or other reason, backup gas is supplied from backup flow path 63 to flow path 9 via junction 65.

[0040] Valve 115 is located between check valve 49 and zero gas flow path branch point 51, and controls the downstream hydrogen gas pressure to 0.1 MPa.

[0041] The switching valve control unit 69 controls the switching valve 13 (not shown) to switch between the sample gas, zero gas, and calibration gas supplied to the hydrogen gas measuring device 3.

[0042] Next, a description will be given of measurement of the CO impurity concentration contained in hydrogen gas by the hydrogen gas measuring device 3. Fig. 3 is a device configuration diagram showing an example of an outline of the hydrogen gas measuring device 3 according to an embodiment of the present invention. Fig. 4 is a flow diagram showing an example of an outline of a measurement process flow in a hydrogen gas analysis method according to an embodiment of the present invention.

[0043] First, distilled water from the distilled water tank 27 is introduced into the water tank 31. Next, the heating control unit 71 controls the Peltier element 33 to heat the water 121 in the water tank (step S01; an example of the "heating step" in the claims of the present application). The hydrogen gas introduced into the hydrogen gas measuring device 3 reaches the humidification flow path 25 immersed in the water of the humidification tank 23 (an example of the "gas supply step" in the claims of the present application). In the humidification flow path 25, the hydrogen gas is humidified (an example of the "humidification step" in the claims of the present application). The water tank 31 is partially open to the atmosphere to prevent the internal pressure from increasing excessively.

[0044] At least a part of the humidification flow path 25 is made of perfluorosulfonated polytetrafluorostyrene (Nafion (registered trademark)). Nafion (registered trademark) can be used as the humidification flow path 25 because it allows water vapor to pass depending on the temperature of the environment. Usually, the humidification flow path 25 is placed in an atmosphere of water vapor in order to speed up the response of the control. However, the inventor of the present application has developed a hydrogen gas measuring device that can measure the impurity concentration with a smaller amount of gas than before. If the flow path allows only a very small amount of gas to flow, it can be humidified sufficiently quickly even when immersed in water. By immersing at least a part of the humidification flow path 25 in the water of the water tank 31, it can be expected that the humidification flow path 25 can be humidified at a stable temperature and humidified stably.

[0045] Particularly in this embodiment, the heating control unit 71 controls the water temperature in the range of 30° C. to 45° C., where the humidification capacity of Nafion (registered trademark) changes linearly with respect to the environmental temperature. Therefore, it is possible to humidify the humidification flow path 25 with good controllability.

[0046] Also, because the humidification flow path 25 is a fine piping (1 / 16"), even if the humidification flow path 25 is immersed in relatively low-temperature water of 30°C to 45°C, the heating control of the water temperature is quickly reflected in the humidity. Furthermore, the use of fine piping in the humidification flow path 25 makes it possible to perform analysis using a much smaller amount of hydrogen gas than in the past. In addition, because humidification is performed at a relatively low temperature, there is no need to expose the entire flow path 9 to high temperatures and pressures, making it easier to maintain safety.

[0047] The humidified hydrogen gas reaches sensor cell 37 in detection chamber 29. In detection chamber 29, humidity sensor 43 measures the humidity, and the measured humidity is fed back to heating control unit 71. Heating control unit 71 controls Peltier element 33 so that the humidity in detection chamber 29 is maintained at 70% RH or higher, for example, within an error range of 70%±0.05% RH.

[0048] The hydrogen pump type sensor cell 37 has an electrolyte membrane (an example of the "electrolyte membrane" in the claims) that does not allow CO impurities to pass through, an anode and a cathode formed to sandwich the electrolyte membrane, a power source 39 connected to the anode and the cathode, and a voltmeter 41 that measures the voltage between the anode and the cathode.

[0049] The resistance value of the sensor cell 37 changes according to the CO impurity concentration contained in the hydrogen gas. The voltmeter 41 measures the voltage of the sensor cell 37 (step S02; an example of a "measurement step" in the claims of the present application). The change in the measured voltage detected by the voltmeter 41 is converted into a CO impurity concentration by the conversion unit 15 (step S03; an example of a "conversion step" in the claims of the present application). The display control unit 77 controls the display unit 17 to display the converted CO impurity concentration (step S04). The control unit 21 determines whether or not to continue the analysis of the sample gas, and if so, returns to step S02. If not, ends the measurement process. The sample gas supplied to the sensor cell 37 and analyzed is exhausted.

[0050] The electrode element used in the sensor cell 37 can measure hydrogen gas, which is the sample gas, by increasing its humidity, but once condensation occurs, the measured value will be abnormal. Also, water droplets will accumulate in the piping, making it impossible to measure hydrogen gas. The humidification flow path 25 of this embodiment does not cause condensation, so it is possible to supply hydrogen gas, which is reliably high in humidity but does not easily condense, to the sensor cell 37 as the sample gas. This makes it possible to analyze hydrogen gas with high accuracy.

[0051] Next, there will be described an operation flow of the hydrogen gas measuring device 3. Fig. 5 is a flow diagram showing an example of an operation flow of the hydrogen gas measuring device 3 in the hydrogen gas analysis method according to the embodiment of the present invention.

[0052] First, zero gas is supplied to the flow path in the hydrogen gas measuring device 3 including the humidification flow path 25 for 80 seconds (step S11; an example of the "gas supply step" in the claims of the present application). Then, the switching valve control unit 69 controls the switching valve 13 to supply the sample gas to the flow path for 10 seconds (step S12; an example of the "gas supply step" and "first sample gas supply step" in the claims of the present application). After that, the switching valve control unit 69 again controls the switching valve 13 to supply zero gas to the flow path for 30 seconds (step S13; an example of the "gas supply step" and "zero gas supply step" in the claims of the present application). Then, the control unit 21 judges whether or not to continue the analysis of the sample gas (step S14). If it is to be continued, the process returns to step S11, and after supplying zero gas for 80 seconds, the sample gas is again supplied for 10 seconds (an example of the "gas supply step" and "second sample gas supply step" in the claims of the present application), and zero gas is supplied for 30 seconds. If it is not to be continued, the measurement flow is terminated. In the above measurement flow, the display control unit 77 controls the display unit 17 to display the change over time in the concentration of CO impurity contained in the hydrogen gas.

[0053] The hydrogen gas analysis method of this embodiment makes it possible to frequently check the zero point, enabling highly accurate analysis in real time.

[0054] In addition, by performing calibration every day, even if changes occur due to impurities adhering to the platinum electrode of the sensor cell 37, it is possible to suppress the drift to zero at the 1 ppb level.

[0055] 6 is a graph showing an example of the change over time in the CO impurity concentration in hydrogen gas actually analyzed by the hydrogen gas analysis system 1 according to this embodiment. Using a standard CO gas cylinder of 210 ppb and a diluter as the calibration gas, four calibration gases were measured at intervals of about 50 ppb in the range of 0 to 210 ppb. The humidity of the sensor cell 37 was 75% RH, and the water temperature in the water tank was 45°C.

[0056] 6, it can be seen that drift is significantly suppressed at each concentration by using the hydrogen gas analysis system 1 of this embodiment. By suppressing drift, it becomes possible to clearly read from the graph the difference in impurity concentration between a hydrogen gas cylinder with a purity of 99.999% and a hydrogen gas cylinder with a purity of 99.99%.

[0057] The zero gas supplied to the hydrogen gas measuring device 3 may be supplied from a zero gas cylinder containing zero gas to the zero gas flow path 45, rather than hydrogen gas branched off from the sample gas flow path 53 and passed through the zero gas filter 47. However, the method of the embodiment in which the zero gas is supplied from the sample gas through the zero gas filter 47 is preferable in that it makes it easier to cancel noise.

[0058] Furthermore, the timing at which the valve control unit 67 controls the backup pressure control valve 61, or the user adjusts the backup pressure control valve to supply backup gas to the backup flow path 63 (an example of a "backup gas pressure control step" in the claims of the present application) may be before or after hydrogen gas is supplied to the flow path 9. Similarly, the timing at which the flow rate control unit 73 controls the flow rate of hydrogen gas flowing through the flow path 9 (an example of a "flow rate control step" in the claims of the present application) is preferably before hydrogen gas is supplied from the hydrogen gas production apparatus 101 to the flow path 9, but may be after the supply has started. [Explanation of symbols]

[0059] 1; hydrogen gas analysis system, 3; hydrogen gas measurement device, 5; zero gas supply device, 7; calibration gas supply device, 9; flow path, 11; valve, 13; switching valve, 15; conversion unit, 17; display unit, 19; backup gas supply device, 21; control unit, 23; humidification tank, 25; humidification flow path, 27; distilled water tank, 29; detection tank, 31; water tank, 33; heater, 35; water thermometer, 37; sensor cell, 39; power supply, 41; voltmeter, 43; humidity sensor, 45; zero gas flow path, 47; zero gas filter, 49; backflow prevention valve, 51; zero gas flow path branch point, 53; sample gas flow path, 55; calibration gas cylinder, 57; calibration gas flow path, 59; backup cylinder, 61; backup pressure control valve, 63; backup flow path, 65; junction, 67; valve control unit, 69; switching valve control unit, 71; heating control unit, 73; flow rate control unit, 75; power supply control unit, 77; display control unit, 101; hydrogen production device, 103; compressor, 105; accumulator, 107; dispenser, 109; valve, 111; backflow prevention valve, 113; backflow prevention valve, 115; valve, 121; water

Claims

1. A hydrogen gas analysis system having a hydrogen pump type sensor for measuring a CO impurity concentration of a sample gas which is hydrogen gas, The hydrogen pump type sensor is An electrolyte membrane that does not allow CO impurities to pass through, a flow path for transmitting the sample gas to the electrolyte membrane; A power source that applies a voltage to the electrolyte membrane; A power supply control unit that controls the power supply, a voltmeter for measuring a voltage applied to the electrolyte membrane; A conversion unit that converts the voltage measured by the voltmeter into the CO impurity concentration; a humidification flow path through which the sample gas is humidified; a tank for holding liquid water; A heater for heating the water; A water temperature measuring unit that measures the water temperature of the water tank; A heating control unit that controls the heater is further provided. At least a portion of the humidification channel is made of perfluorosulfonated polytetrafluorostyrene; the humidification flow path is at least partially immersed in the water of the water tank; A hydrogen gas analysis system, wherein the heating control unit controls the heater so that the water is in the temperature range of 30°C to 45°C.

2. a switching valve that switches between the supply of the sample gas to be analyzed and a zero gas that does not contain the CO impurity, to the electrolyte membrane; A switching valve control unit that controls the switching valve is further provided.

2. The hydrogen gas analysis system of claim 1, wherein the switching valve control unit controls the switching valve to supply the sample gas to the electrolyte membrane, switch the switching valve to supply the zero gas for 120 seconds or less, and then switch the switching valve again to supply the sample gas.

3. a backup flow path that supplies a backup gas and is connected to the flow path through which the sample gas is supplied to the electrolyte membrane at a junction located midway; a backup pressure control valve for controlling a pressure of the backup gas supplied to the backup flow path, 3. The hydrogen gas analyzing system according to claim 1, wherein the backup pressure control valve is capable of controlling the pressure of the backup gas at the junction to a pressure lower than the pressure of the sample gas.

4. 4. The hydrogen gas analysis system according to claim 1, further comprising a flow rate control unit that supplies the sample gas to the humidification channel at a flow rate of 200 mL / min or less.

5. A hydrogen gas analysis method using a hydrogen gas analysis system having a hydrogen pump type sensor and measuring a CO impurity concentration of a sample gas which is hydrogen gas, comprising: The hydrogen pump type sensor is An electrolyte membrane that does not allow CO impurities to pass through, a flow path for transmitting the sample gas to the electrolyte membrane; A power source that applies a voltage to the electrolyte membrane; A power supply control unit that controls the power supply, The hydrogen gas analysis system includes: a voltmeter for measuring a voltage applied to the electrolyte membrane; A conversion unit that converts the voltage measured by the voltmeter into the CO impurity concentration; a humidification flow path through which the sample gas is humidified; a tank for holding liquid water; A heater for heating the water; A water temperature measuring unit that measures the water temperature of the water tank; A heating control unit that controls the heater is further provided. At least a portion of the humidification channel is made of perfluorosulfonated polytetrafluorostyrene; the humidification flow path is at least partially immersed in the water of the water tank; a heating step in which the heating control unit controls the heater so that the water has a temperature in the range of 30° C. to 45° C.; a gas supply step in which the sample gas or a zero gas not containing the CO impurity is supplied to the humidification flow path; a humidification step in which the humidification flow path is immersed in water held in the water tank and humidified; a measuring step in which the voltmeter measures a voltage applied to the electrolyte membrane; and a conversion step in which the conversion unit converts the voltage measured by the voltmeter into the CO impurity concentration.

6. The hydrogen gas analysis system includes: a switching valve for switching the supply of the sample gas to be analyzed and the zero gas to the electrolyte membrane; A switching valve control unit that controls the switching valve is further provided. In the gas supplying step, The switching valve control unit controls the switching valve to supply the electrolyte membrane with a first sample gas supply step of supplying the sample gas; a zero gas supplying step of supplying the zero gas for 120 seconds or less; 6. The hydrogen gas analysis method according to claim 5, further comprising a second sample gas supply step of supplying the sample gas again.

7. The hydrogen gas analysis system includes: a backup flow path that supplies a backup gas and is connected to the flow path through which the sample gas is supplied to the electrolyte membrane at a junction located midway; a backup pressure control valve for controlling a pressure of the backup gas supplied to the backup flow path, 7. The hydrogen gas analysis method according to claim 5, further comprising a backup gas pressure control step in which the backup pressure control valve controls the pressure of the backup gas at the junction to a pressure lower than the pressure of the sample gas in the gas supply step.

8. The hydrogen gas analysis system further includes a flow rate control unit that supplies the sample gas to the humidification flow path at a flow rate of 200 mL / min or less.

8. The hydrogen gas analysis method according to claim 5, further comprising a flow rate control step in which, in the gas supply step, the flow rate control unit supplies the sample gas or the zero gas to the flow path at a flow rate of 200 mL / min or less.

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