JP6786445B2 - Hydrogen concentration measurement system, method and program - Google Patents

Description

An embodiment of the present invention relates to a hydrogen concentration measuring technique using a hydrogen storage material.

The hydrogen concentration measurement system using the hydrogen storage material measures the hydrogen concentration in the surrounding environment by utilizing the property that the electric resistance value increases as the hydrogen storage amount of the hydrogen storage material increases.
Therefore, it is ideal that the electric resistance value is constant when there is no change in the surrounding environment and there is no inflow and outflow of hydrogen stored in the hydrogen storage material.

However, due to aging such as internal strain of the hydrogen storage material, the electric resistance value may change even though the hydrogen concentration in the surrounding environment does not change, and the measurement accuracy of the hydrogen concentration may decrease.
For this reason, the hydrogen concentration measurement system maintains the measurement accuracy of the hydrogen concentration by periodically performing calibration.

Japanese Unexamined Patent Publication No. 2015-145859

However, the calibration work of the conventional hydrogen concentration measurement system has problems such as temporary interruption of hydrogen concentration measurement and interference with other work simultaneously progressing in the plant, so the frequency of implementation is reduced. There is a desire to do so.

An embodiment of the present invention has been made in consideration of such circumstances, and provides a hydrogen concentration measurement technique capable of performing calibration work without interrupting hydrogen concentration measurement in a plant or involving attachment / detachment of equipment. With the goal.

The hydrogen concentration measuring system according to the embodiment includes a temperature signal acquisition unit that acquires a signal of a temperature detection value from a temperature sensor arranged in the vicinity of a hydrogen storage material that changes the hydrogen storage amount according to the hydrogen concentration in the atmosphere, and the above. A calculation unit that inputs the temperature detection value into the calculation formula to calculate the standard resistance value of the hydrogen storage material when the hydrogen storage amount is zero, and a resistance signal acquisition that acquires the signal of the resistance detection value of the hydrogen storage material. A unit, a calculation unit that calculates the resistance change rate of the hydrogen storage material based on the resistance detection value and the standard resistance value, a derivation unit that derives the hydrogen concentration of the atmosphere based on the resistance change rate, and the above. and a calibration unit that executes a calibration before hexane Deshiki when hydrogen storage capacity baseline of the resistance detection value or the resistance change rate in a direction further decreases from zero drift, the calculating formula, the function expression that defines the temporal change of the resistance value detected by the time variable, Ru is introduced as a parameter.

An embodiment of the present invention provides a hydrogen concentration measurement technique capable of performing calibration work without interrupting hydrogen concentration measurement in a plant or involving attachment / detachment of equipment.

The block diagram of the hydrogen concentration measurement system which concerns on embodiment of this invention. The explanatory view of the concept of calibration in the hydrogen concentration measurement system which concerns on embodiment. The flowchart of the hydrogen concentration measurement method and the hydrogen concentration measurement program which concerns on embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
As shown in FIG. 1, the hydrogen concentration measuring system 10 according to the embodiment includes a hydrogen detector 20 and a signal processing unit 30.

The signal processing unit 30 of the hydrogen concentration measurement system acquires a temperature signal of a temperature detection value T from a temperature sensor 22 arranged in the vicinity of the hydrogen storage material 21 that changes the hydrogen storage amount according to the hydrogen concentration in the atmosphere. A signal of the resistance detection value R of the hydrogen storage material 21 and the calculation unit 35 for inputting the temperature detection value T and calculating the standard resistance value S of the hydrogen storage material 21 when the hydrogen storage amount is zero is input to the unit 31. The resistance signal acquisition unit 32 to be acquired, the calculation unit 36 that calculates the resistance change rate Q of the hydrogen storage material 21 based on the resistance detection value R and the standard resistance value S, and the hydrogen concentration G in the atmosphere based on the resistance change rate Q. When the baseline of the resistance detection value R or the resistance change rate Q drifts in the direction in which the hydrogen storage amount further decreases from zero, the derivation unit 39 that derives the standard resistance value S is calibrated. It includes a part 38 and.

Further, the signal processing unit 30 of the hydrogen concentration measurement system includes a determination unit 37 that determines a baseline drift of the resistance detection value R or the resistance change rate Q, and a hydrogen storage material by the operator inputting temperature information to the setting unit 42. A heater control unit 41 that changes the temperature of 21 is further provided.

The hydrogen detector 20 includes a hydrogen storage material 21 and a temperature sensor 22 wound in a solenoid shape around the first winding core 23 while maintaining insulation from each other, and a second volume coaxially arranged on the outside of the first winding core 23. It is composed of a heater wire 25 wound in a solenoid shape around a core 27 and a temperature gauge 26 for temperature control of the heater wire 25.

The first winding core 23 and the second winding core 27 have a solid or hollow cylindrical shape made of an insulating material. The hydrogen storage material 21 has a property of absorbing hydrogen by cooling or pressurizing and releasing hydrogen by heating or depressurizing. The hydrogen storage material 21 is widely known to be made of an alloy as a material, but is not particularly limited.

The amount of hydrogen stored in the hydrogen storage material 21 changes depending on the pressure and temperature of hydrogen, and a PCT curve (not shown) showing the relationship between the hydrogen pressure at a constant temperature and the amount of hydrogen stored is known. According to this PCT curve, when the amount of hydrogen stored in the hydrogen storage material 21 is small, the amount of hydrogen stored increases in proportion to the 1/2 power of the hydrogen pressure. When the hydrogen storage amount further increases, hydrides begin to be formed, and a region (plateau region) appears in which the hydrogen storage amount increases but the hydrogen pressure does not increase. When all are hydrides, the amount of hydrogen stored increases again as the hydrogen pressure rises.

Further, when the temperature of the hydrogen storage material 21 rises, the pressure at which the plateau region appears also rises, and the plateau region itself gradually disappears.
When the hydrogen storage material 21 is used as a hydrogen concentration measurement sensor, it is necessary to heat it to a temperature at which the plateau region disappears so that the hydrogen pressure and the hydrogen storage amount have a one-to-one relationship with each other.

The heater control unit 41 feedback-controls the amount of electricity supplied to the heater wire 25 so that the temperature gauge 26 arranged in the vicinity of the heater wire 25 reaches the temperature set by the setting unit 42. The temperature set by the setting unit 42 is set to a temperature at which the plateau region on the PCT curve of the hydrogen storage material 21 sufficiently disappears.

The temperature signal acquisition unit 31 acquires a signal of the temperature detection value T output from the temperature sensor 22 arranged in the vicinity of the hydrogen storage material 21. The temperature sensor 22 is composed of a resistance temperature detector, and utilizes the characteristic that the electric resistance value changes with a temperature change, converts the detected electric resistance into a temperature detection value T, and outputs the detected electric resistance. A bridge circuit (not shown) is connected to the temperature sensor 22, and the resistance is detected by the bridge circuit, converted into a temperature detection value T, and then a signal is output to the acquisition unit 31.

The resistance signal acquisition unit 32 acquires a signal of the resistance detection value R of the hydrogen storage material 21. A bridge circuit (not shown) is also connected to the hydrogen storage material 21, and the resistance detection value R detected by the bridge circuit is output as a signal to the acquisition unit 32.
The resistance detection value R of the hydrogen storage material 21 has a property of increasing not only with its own temperature rise but also with an increase in the hydrogen storage amount. Therefore, by acquiring the temperature detection value T and the resistance detection value R of the hydrogen storage material 21, the hydrogen concentration G in the atmosphere can be finally derived.

The calculation unit 35 substitutes the acquired temperature detection value T into the calculation formula 33 represented by the following formula, and calculates the standard resistance value S of the hydrogen storage material 21 when the hydrogen storage amount is zero.
Here, A, B, and C in the calculation formula 33 are constants experimentally determined for each individual hydrogen detector 20 by measuring the resistance value while changing the temperature in an atmosphere where the hydrogen concentration is zero. ..
Standard resistance value S = A × T ² + B × T + C (33)

The calculation unit 36 substitutes the acquired resistance detection value R and the calculated standard resistance value S into the following equation to calculate the resistance change rate Q of the hydrogen storage material 21.
Resistance change rate Q (%) = (resistance detection value R-standard resistance value S) / standard resistance value S x 100

In the ideal state, when the hydrogen concentration in the atmosphere is zero, the resistance change rate Q should take a value close to 0% regardless of the ambient temperature. However, when the baseline of the resistance detection value R drifts in the negative direction over time, not only the measurement accuracy of the hydrogen concentration G decreases, but also the hydrogen concentration G is derived to be lower than the actual value. Will be.

As shown in FIG. 2A, the determination unit 37 compares the average value A of the resistance change rate Q for a certain period M with the set threshold value m. Each time the resistance change rate Q is newly calculated from the resistance detection value R, the determination unit 37 calculates the average value A of the plurality of resistance change rates Q for a certain period of time M from that time point.
When this average value A is larger than the threshold value m set as a negative value, it is determined that there is no downward drift of the baseline of the resistance detection value R, and the hydrogen concentration G is determined based on this resistance change rate Q. Derived.
On the other hand, when this average value A is smaller than the threshold value m set as a negative value, it is determined that there is a downward drift of the baseline of the resistance detection value R, and the calibration unit 38 calibrates the calculation formula 33. The sequence is started.

When the calibration unit 38 determines that there is a drift, as shown in FIG. 2 (B), the function formula ΔR represented by the following formula is used as a parameter of the calculation formula 33 based on the change over time of the resistance detection value R. Introduce. Here, t in the function equation ΔR is a time variable, and D and E are coefficients of the linear equation obtained by approximation.
ΔR = D ・ t + E

By this calibration sequence, the calculation formula 33 of the standard resistance value S is updated as follows.
Update standard resistance value S'= A × T ² + B × T + C− △ R

The period N (FIG. 2 (B)) for deriving this functional formula ΔR may be the past based on the time when it is determined that there is drift, or before the hydrogen detector 20 is installed in the plant. The inspection period may be adopted, and is not particularly limited.
As a result, the error due to the downward drift of the baseline of the resistance detection value R is corrected, and the measurement accuracy of the hydrogen concentration G in the derivation unit 39 can be improved.

The derivation unit 39 is provided in advance with a table showing the relationship between the resistance change rate Q and the hydrogen concentration G at various temperature detection values T. Then, while referring to this table, the hydrogen concentration G of the atmosphere is derived based on the input resistance change rate Q.

When the baseline of the resistance detection value R drifts, the input of the heater temperature setting unit 42 may be changed to change the temperature of the hydrogen storage material 21 to stabilize the temperature before starting the above calibration sequence. is there.
As a result, the temperature detection value T assigned to the calculation formula 33 in the calculation unit 35 is updated, the standard resistance value S and the resistance detection value R input to the calculation unit 36 also change, and the output resistance change rate Q Also changes. Subsequent operations of the determination unit 37 and the calibration unit 38 are as described above.
As a result, it may be possible to perform a more accurate correction.

The hydrogen concentration measuring method and the hydrogen concentration measuring program according to the embodiment will be described with reference to the flowchart of FIG. 3 (see FIG. 1 as appropriate).
A set value of the heater temperature is input to the setting unit 42 (S11), and the temperature detection value T acquired from the hydrogen detector 20 is waited for stabilization (S12 No, Yes). Then, the calculation formula 33 for calculating the standard resistance value S of the hydrogen storage material 21 when the hydrogen storage amount is zero, including the experimentally determined constants A, B, and C, is acquired with the temperature as an input variable. (S13). The signal of the temperature detection value T of the hydrogen storage material 21 acquired from the hydrogen detector 20 is substituted into this calculation formula 33 (S14), and the standard resistance value S of the hydrogen storage material 21 at the temperature detection value T is calculated (S15). ).

Next, the signal of the resistance detection value R of the hydrogen storage material 21 is acquired from the hydrogen detector 20 (S16), and the resistance change rate Q of the hydrogen storage material is calculated based on the resistance detection value R and the standard resistance value S. (S17). Then, the hydrogen concentration G of the atmosphere is output based on the resistance change rate Q (S17). Further, when the measurement of the hydrogen concentration is continued (S19 Yes), it is determined whether or not the baseline of the resistance change rate Q drifts in the direction in which the hydrogen storage amount further decreases from zero.

In this drift determination, the average value A of the resistance change rate Q for a certain period M and the set threshold value m are compared, and if the average value A is larger than the negatively set threshold value m, there is no baseline drift. The determination is made (S20 No), and the flow from (S14) is repeated.

On the other hand, if the average value A is equal to or less than the negatively set threshold value m, it is determined that there is a baseline drift (S20 Yes), and the calibration of the calculation formula 33 is started. By this calibration, the functional formula ΔR obtained based on the change with time of the resistance detection value R in the past (period N) is introduced as a parameter, and the calculation formula 33 is updated (S21).
Then, when it is determined that there is a baseline drift, the updated calculation formula 33 is reacquired (S13), the subsequent flow is repeated, and the hydrogen concentration measurement continues until the continuation is interrupted (S19). Yes No END).

According to the hydrogen concentration measurement system of at least one embodiment described above, the calibration work is simplified by performing the drift determination of the baseline signal in the direction in which the hydrogen storage amount of the hydrogen storage material further decreases from zero. It is possible to maintain high accuracy in hydrogen concentration measurement.

Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, changes, and combinations can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, as well as in the scope of the invention described in the claims and the equivalent scope thereof.
In addition, the components of the hydrogen concentration measurement system can be realized by a computer processor, and can be operated by a hydrogen concentration measurement program.

The hydrogen concentration measurement system described above includes a control device in which processors such as a dedicated chip, FPGA (Field Programmable Gate Array), GPU (Graphics Processing Unit), or CPU (Central Processing Unit) are highly integrated, and a ROM ( Storage devices such as Read Only Memory) and RAM (Random Access Memory), external storage devices such as HDD (Hard Disk Drive) and SSD (Solid State Drive), display devices such as displays, and input such as mouse and keyboard. It is equipped with a device and a communication I / F, and can be realized by a hardware configuration using a normal computer.

Further, the program executed by the hydrogen concentration measurement system is provided by incorporating it into a ROM or the like in advance. Alternatively, the program is provided as a file in an installable or executable format stored on a computer-readable storage medium such as a CD-ROM, CD-R, memory card, DVD, or flexible disk (FD). You may try to do it.

Further, the program executed by the hydrogen concentration measurement system according to the present embodiment may be stored on a computer connected to a network such as the Internet, and may be downloaded and provided via the network.
In addition, the hydrogen concentration measurement system can also be configured by connecting separate modules that independently exert each function of the components to each other by a network or a dedicated line and combining them.

10 ... Hydrogen concentration measurement system, 20 ... Hydrogen detector, 21 ... Hydrogen storage material, 22 ... Temperature sensor, 23 ... Wind core, 25 ... Heater wire, 26 ... Thermometer, 27 ... Wind core, 30 ... Signal processing unit , 31 ... Temperature signal acquisition unit, 32 ... Resistance signal acquisition unit, 33 ... Calculation formula, 35 ... Calculation unit, 36 ... Calculation unit, 37 ... Judgment unit, 38 ... Calibration unit, 39 ... Derivation unit, 41 ... Heater control unit , 42 ... heater temperature setting unit, 42 ... setting unit, G ... hydrogen concentration, Q ... resistance change rate, R ... resistance detection value, ΔR ... functional formula, S ... standard resistance value, T ... temperature detection value.

Claims (5)

A temperature signal acquisition unit that acquires a temperature detection value signal from a temperature sensor located near the hydrogen storage material that changes the hydrogen storage amount according to the hydrogen concentration in the atmosphere.
A calculation unit that inputs the temperature detection value into the calculation formula and calculates the standard resistance value of the hydrogen storage material when the hydrogen storage amount is zero.
A resistance signal acquisition unit that acquires a signal of the resistance detection value of the hydrogen storage material, and
An arithmetic unit that calculates the resistance change rate of the hydrogen storage material based on the resistance detection value and the standard resistance value, and
A derivation unit that derives the hydrogen concentration of the atmosphere based on the resistance change rate,
If the hydrogen storage capacity is the baseline of the resistance detection value or the resistance change rate in a direction further decreases from zero drift, and a calibration unit that executes a calibration before hexane Deshiki,
Hydrogen concentration measuring system the calculation formula, the function expression that defines the temporal change of the resistance value detected by the time variable, and wherein the Rukoto introduced as a parameter. In the hydrogen concentration measuring system according to claim 1,
A hydrogen concentration measuring system further comprising a determination unit for determining a baseline drift by comparing an average value of the resistance change rate for a certain period with a set threshold value. In the hydrogen concentration measuring system according to claim 1 or 2 .
A heater control unit that changes the temperature of the hydrogen storage material is further provided.
A hydrogen concentration measuring system characterized in that the temperature of the hydrogen storage material is changed when a drift of the baseline is observed. The step of acquiring the signal of the temperature detection value from the temperature sensor placed near the hydrogen storage material that changes the hydrogen storage amount according to the hydrogen concentration of the atmosphere, and
A step of inputting the temperature detection value into the calculation formula and calculating the standard resistance value of the hydrogen storage material when the hydrogen storage amount is zero, and
The step of acquiring the signal of the resistance detection value of the hydrogen storage material and
A step of calculating the resistance change rate of the hydrogen storage material based on the resistance detection value and the standard resistance value, and
The step of deriving the hydrogen concentration of the atmosphere based on the resistance change rate, and
If the hydrogen storage capacity is the baseline of the resistance detection value or the resistance change rate in a direction further decreases from zero drift, comprising performing a calibration of the pre-hexane Deshiki, a,
The calculation formula is a hydrogen concentration measuring method characterized in that a functional formula in which a change with time of the resistance detection value is defined by a time variable is introduced as a parameter . A step of acquiring a temperature detection value signal from a temperature sensor placed in the vicinity of a hydrogen storage material that changes the hydrogen storage amount according to the hydrogen concentration in the atmosphere on the computer.
A step of inputting the temperature detection value into the calculation formula and calculating the standard resistance value of the hydrogen storage material when the hydrogen storage amount is zero.
Step of acquiring the signal of the resistance detection value of the hydrogen storage material,
A step of calculating the resistance change rate of the hydrogen storage material based on the resistance detection value and the standard resistance value,
Step of deriving the hydrogen concentration of the atmosphere based on the resistance change rate,
If the hydrogen storage capacity is the baseline of the resistance detection value or the resistance change rate in a direction further decreases from zero drift, performing a calibration of the pre-hexane Deshiki,
To execute,
The calculation formula, the function formula that defines the temporal change of the resistance value detected by the time variable, the hydrogen concentration measurement program characterized Rukoto introduced as a parameter.

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