JP2019002707A - Hydrogen concentration measurement system, method, and program - Google Patents

Abstract

To provide a hydrogen concentration measurement technique capable of performing calibration which does not accompany interruption of hydrogen concentration measurement and attachment and detachment of a device in a plant.SOLUTION: A hydrogen concentration measurement system comprises: a temperature signal acquisition unit 31 which acquires a temperature detection value T signal from a temperature sensor 22 arranged near a hydrogen storage material 21; a calculation unit 35 which inputs the temperature detection value T and calculates a standard resistance value S; a resistance signal acquisition unit 32 which acquires a resistance detection value R signal of the hydrogen storage material 21; an arithmetic logical unit 36 which calculates a resistance change rate Q on the basis of the resistance detection value R and the standard resistance value S; a derivation unit 39 which derives atmospheric hydrogen concentration G on the basis of the resistance change rate Q; and a calibration unit 38 which calibrates a calculation formula 33 of the standard resistance value S when a baseline of the resistance detection value R or the resistance change rate Q drifts.SELECTED DRAWING: Figure 1

Description

  Embodiments described herein relate generally to a hydrogen concentration measurement 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 electrical resistance value increases as the hydrogen storage amount in the hydrogen storage material increases.
Therefore, it is ideal that the electrical resistance value is constant in a state where there is no change in the surrounding environment and there is no entry / exit of hydrogen stored in the hydrogen storage material.

However, due to secular changes such as internal strain of the hydrogen storage material, the electrical resistance value may change even though the hydrogen concentration in the surrounding environment remains unchanged, 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 Patent Laying-Open No. 2015-145859

  However, the calibration work of the conventional hydrogen concentration measurement system has problems such as temporarily interrupting the hydrogen concentration measurement and interfering with other operations that proceed simultaneously in the plant. There is a desire to want.

  Embodiments of the present invention have been made in view of such circumstances, and provide a hydrogen concentration measurement technique capable of performing a calibration operation without interrupting the measurement of hydrogen concentration in the plant and without attaching or detaching equipment. With the goal.

  The hydrogen concentration measurement 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 a hydrogen storage amount according to the hydrogen concentration of the atmosphere, and A calculation unit that inputs a temperature detection value and calculates a 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 a resistance detection value of the hydrogen storage material; A calculation unit that calculates a resistance change rate of the hydrogen storage material based on the resistance detection value and the standard resistance value, a derivation unit that derives a hydrogen concentration of the atmosphere based on the resistance change rate, and the hydrogen storage amount A calibration unit that calibrates the calculation formula of the standard resistance value when the resistance detection value or the baseline of the resistance change rate drifts in a direction in which the resistance value further decreases from zero.

  According to the embodiment of the present invention, a hydrogen concentration measurement technique capable of performing a calibration operation without interrupting the measurement of hydrogen concentration in a plant or accompanying attachment / detachment of equipment is provided.

1 is a block diagram of a hydrogen concentration measurement system according to an embodiment of the present invention. Explanatory drawing of the concept of the calibration in the hydrogen concentration measurement system which concerns on embodiment. The flowchart of the hydrogen concentration measuring method and hydrogen concentration measuring program which concern 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 measurement 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 value T from a temperature sensor 22 disposed in the vicinity of the hydrogen storage material 21 that changes the hydrogen storage amount according to the hydrogen concentration of the atmosphere. A calculation unit 35 for calculating the standard resistance value S of the hydrogen storage material 21 when the hydrogen storage amount is zero by inputting the temperature detection value T, and a signal of the resistance detection value R of the hydrogen storage material 21. A resistance signal acquisition unit 32 to acquire, a calculation unit 36 for calculating 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 of the atmosphere based on the resistance change rate Q A derivation unit 39 for deriving the value, and a calibration for performing calibration of the calculation formula 33 of the standard resistance value S when the baseline of the resistance detection value R or the resistance change rate Q drifts in a direction in which the hydrogen storage amount further decreases from zero Part 38; Eteiru.

  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 the operator inputs temperature information to the setting unit 42 so that the hydrogen storage material And a heater control unit 41 that varies the temperature of 21.

  The hydrogen detector 20 includes a hydrogen storage material 21 and a temperature sensor 22 that are wound around the first winding core 23 in a solenoid shape while maintaining insulation from each other, and a second winding that is coaxially disposed outside the first winding core 23. The heater wire 25 is wound around the core 27 like a solenoid, and a thermometer 26 for controlling the temperature of the heater wire 25 is formed.

  The first core 23 and the second 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 pressurization and releasing hydrogen by heating or decompression. The hydrogen storage material 21 is widely known as an alloy 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 and the hydrogen storage amount at a constant temperature is known. According to this PCT curve, when the amount of hydrogen stored in the hydrogen storage material 21 is small, the amount of stored hydrogen increases in proportion to the 1/2 power of the hydrogen pressure. When the hydrogen storage amount further increases, a hydride begins to be formed, and a region (plateau region) where the hydrogen storage amount increases but the hydrogen pressure does not increase appears. When everything becomes hydride, the hydrogen storage amount increases again as the hydrogen pressure increases.

Further, when the temperature of the hydrogen storage material 21 rises, the pressure at which the plateau region appears increases, 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 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.

  The heater control unit 41 feedback-controls the energization amount to the heater wire 25 so that the thermometer 26 arranged in the vicinity of the heater wire 25 has 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 disappears sufficiently.

  The temperature signal acquisition unit 31 acquires a signal of the temperature detection value T output from the temperature sensor 22 disposed in the vicinity of the hydrogen storage material 21. This temperature sensor 22 is constituted by a resistance temperature detector, and utilizes the characteristic that the electric resistance value changes with temperature change, and converts the detected electric resistance into a temperature detection value T and outputs it. A bridge circuit (not shown) is connected to the temperature sensor 22, the resistance is detected by this bridge circuit, converted into a temperature detection value T, and then 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 a 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 amount of hydrogen storage. For this reason, by obtaining the temperature detection value T and the resistance detection value R of the hydrogen storage material 21, the hydrogen concentration G of 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 varying 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 calculates the resistance change rate Q of the hydrogen storage material 21 by substituting the acquired resistance detection value R and the calculated standard resistance value S into the following equation.
Resistance change rate Q (%) = (resistance detection value R−standard resistance value S) / standard resistance value S × 100

  In an ideal state, in a state where 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 with time, not only the measurement accuracy of the hydrogen concentration G is lowered, but also the hydrogen concentration G is derived lower than the actual measurement. End up.

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

When it is determined that there is a drift, the calibration unit 38 uses a function equation ΔR expressed by the following equation as a parameter of the calculation equation 33 based on the change over time of the resistance detection value R, as shown in FIG. Introduce. Here, t in the function expression ΔR is a time variable, and D and E are coefficients of a linear expression obtained by approximation.
ΔR = D · t + E

With this calibration sequence, the calculation formula 33 for the standard resistance value S is updated as shown in the following formula.
Update standard resistance value S ′ = A × T ² + B × T + C−ΔR

Note that the period N (FIG. 2 (B)) for deriving this functional equation ΔR may be the past based on the time when the determination that there is a drift occurs, 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 drift in the decrease direction 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 deriving unit 39 is previously provided with a table representing the relationship between the resistance change rate Q and the hydrogen concentration G at various temperature detection values T. Then, 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 above-described calibration sequence may be started after changing the input of the heater temperature setting unit 42 and changing the temperature of the hydrogen storage material 21 to stabilize the temperature. is there.
Thereby, the temperature detection value T substituted into the calculation formula 33 is updated in the calculation unit 35, the standard resistance value S and the resistance detection value R input to the calculation unit 36 also change, and the resistance change rate Q output. Also changes. The subsequent operations of the determination unit 37 and the calibration unit 38 are as described above.
As a result, correction with higher accuracy may be performed.

A hydrogen concentration measurement method and a hydrogen concentration measurement program according to the embodiment will be described based on the flowchart of FIG. 3 (see FIG. 1 as appropriate).
The setting 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). And the calculation formula 33 which calculates the standard resistance value S of the hydrogen occlusion material 21 when the hydrogen occlusion amount is zero, including constants A, B, and C determined experimentally 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, a signal of the resistance detection value R of the hydrogen storage material 21 is obtained 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 is drifting in a 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 is compared with the set threshold value m, and if this average value A is larger than the negative threshold value m, there is no baseline drift. It is determined (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 minus threshold value m, it is determined that there is a baseline drift (S20 Yes), and the process proceeds to calibration of the calculation formula 33. As a result of this calibration, a function formula ΔR obtained based on the temporal change of the resistance detection value R in the past (period N) is introduced as a parameter, and the calculation formula 33 is updated (S21).
If the baseline drift determination is made, the updated calculation formula 33 is re-acquired (S13), the subsequent flow is repeated, and the measurement of the hydrogen concentration 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 operation can be simplified by performing the drift determination of the baseline signal in a direction in which the hydrogen storage amount of the hydrogen storage material further decreases from zero. The hydrogen concentration measurement can be maintained with high accuracy.

Although several embodiments of the present invention have been described, these embodiments are presented by way of example 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 scope of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.
The components of the hydrogen concentration measurement system can also 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 dedicated device, a control device in which a processor such as an FPGA (Field Programmable Gate Array), a GPU (Graphics Processing Unit), or a CPU (Central Processing Unit) is highly integrated, and a ROM ( Storage devices such as Read Only Memory (RAM) and Random Access Memory (RAM), external storage devices such as HDD (Hard Disk Drive) and SSD (Solid State Drive), display devices such as a display, and inputs such as a mouse and a keyboard The apparatus and the communication I / F are provided, and can be realized by a hardware configuration using a normal computer.

  A program executed by the hydrogen concentration measurement system is provided by being incorporated in advance in a ROM or the like. Alternatively, this program is stored in a computer-readable storage medium such as a CD-ROM, CD-R, memory card, DVD, or flexible disk (FD) as an installable or executable file. You may make it do.

Further, the program executed in 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 provided by being downloaded via the network.
In addition, the hydrogen concentration measurement system can also be configured by connecting separate modules that perform each function of the components independently by a network or a dedicated line.

  DESCRIPTION OF SYMBOLS 10 ... Hydrogen concentration measuring system, 20 ... Hydrogen detector, 21 ... Hydrogen occlusion material, 22 ... Temperature sensor, 23 ... Core, 25 ... Heater wire, 26 ... Thermometer, 27 ... Core, 30 ... Signal processing part , 31 ... Temperature signal acquisition unit, 32 ... Resistance signal acquisition unit, 33 ... Calculation formula, 35 ... Calculation unit, 36 ... Calculation unit, 37 ... Determination 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 equation, S: standard resistance value, T: temperature detection value.

Claims (6)

A temperature signal acquisition unit that acquires a signal of a temperature detection value from a temperature sensor arranged in the vicinity of the hydrogen storage material that changes the hydrogen storage amount according to the hydrogen concentration of the atmosphere;
A calculation unit that inputs the temperature detection value and calculates a standard resistance value of the hydrogen storage material when the hydrogen storage amount is zero;
A resistance signal acquisition unit for acquiring a signal of a resistance detection value of the hydrogen storage material;
A calculation unit for calculating a resistance change rate of the hydrogen storage material based on the resistance detection value and the standard resistance value;
A deriving unit for deriving the hydrogen concentration of the atmosphere based on the resistance change rate;
A calibration unit that calibrates the calculation formula of the standard resistance value when the resistance detection value or the baseline of the rate of change in resistance drifts in a direction in which the hydrogen storage amount further decreases from zero. A hydrogen concentration measurement system. The hydrogen concentration measurement system according to claim 1,
The hydrogen concentration measurement system further comprising a determination unit that determines the drift of the baseline by comparing an average value of the resistance change rate over a certain period and a set threshold value. In the hydrogen concentration measurement system according to claim 1 or 2,
The calibration unit introduces a function formula obtained based on a change with time in the resistance detection value into a parameter of the calculation formula. In the hydrogen concentration measuring system according to any one of claims 1 to 3,
A heater control unit that varies the temperature of the hydrogen storage material;
A hydrogen concentration measurement system that varies the temperature of the hydrogen storage material when drift of the baseline is observed. Obtaining a temperature detection value signal from a temperature sensor arranged in the vicinity of the hydrogen storage material that changes the hydrogen storage amount according to the hydrogen concentration of the atmosphere;
Inputting the temperature detection value and calculating a standard resistance value of the hydrogen storage material when the hydrogen storage amount is zero;
Obtaining a signal of a resistance detection value of the hydrogen storage material;
Calculating a resistance change rate of the hydrogen storage material based on the resistance detection value and the standard resistance value;
Deriving a hydrogen concentration of the atmosphere based on the resistance change rate;
Performing calibration of the calculation formula for the standard resistance value when the resistance detection value or the baseline of the rate of change in resistance drifts in a direction in which the hydrogen storage amount further decreases from zero. To measure hydrogen concentration. Obtaining a temperature detection value signal from a temperature sensor arranged in the vicinity of a hydrogen storage material that changes a hydrogen storage amount according to the hydrogen concentration of the atmosphere in a computer;
Inputting the temperature detection value and calculating a standard resistance value of the hydrogen storage material when the hydrogen storage amount is zero;
Obtaining a resistance detection value signal of the hydrogen storage material;
Calculating a resistance change rate of the hydrogen storage material based on the resistance detection value and the standard resistance value;
Deriving a hydrogen concentration of the atmosphere based on the resistance change rate;
Performing calibration of the calculation formula of the standard resistance value when the resistance detection value or the baseline of the rate of change in resistance drifts in a direction in which the hydrogen storage amount further decreases from zero. To measure hydrogen concentration.

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