JP2011203217A - Gas control system and the gas control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas control system that simply and appropriately measures a calorific value of a combustible gas, and properly controls the mixing of the combustible gas and a combustion supporting gas.SOLUTION: The gas control system is equipped with a calorific value calculation system 21A that includes: a measuring mechanism that measures a value of heat radiation coefficient or thermal conductivity of a combustible gas when a heating element heats at a plurality of heating temperatures; a formula storing device for storing a calorific value calculation formula in which the heat radiation coefficient or thermal conductivity to a plurality of heating temperatures are set to be independent variables and the calorific value is set to be dependent variable; and a calorific value calculation section for calculating the calorific value of the combustible gas by substituting the independent variables of the heat radiation coefficient or thermal conductivity to a plurality of heating temperatures in the calorific value calculation formula with the values of the heat radiation coefficient or thermal conductivity to a plurality of heating temperatures. The gas control system is further equipped with: a control device 150 for controlling the mixing of the combustible gas and a combustion supporting gas based on the calculated value of the calorific value of the combustible gas.

Description

  The present invention relates to gas technology, and relates to a gas control system and a gas control method.

  In Europe, America and Asia, it is common to supply natural gas from a gas field using a pipeline. Natural gas contains nitrogen and carbon dioxide, which are non-caloric components, as impurities in addition to the main component alkane such as methane. For this reason, the amount of heat supplied per unit time may vary greatly. When combustible gas is burned, in order to avoid incomplete combustion, an amount of air that allows a surplus from the theoretical air amount necessary for complete combustion, so-called excess air amount, is mixed with the combustible gas. In particular, in the case of natural gas, an excessive amount of air tends to be mixed in anticipation of large fluctuations in the amount of heat. However, when the excess air amount is mixed with the combustible gas, the excess air takes heat and reduces the amount of heat obtained by heat exchange.

  Therefore, in order to burn the combustible gas efficiently, it has been proposed to analyze the composition of the combustible gas before mixing with air with a gas chromatography apparatus and measure the calorific value of the combustible gas. In addition, in order to bring the air-fuel ratio of the combustion-supporting gas such as air and the combustible gas close to the stoichiometric air-fuel ratio, the oxygen concentration in the combustion exhaust gas is measured with an oxygen sensor, and based on the measured oxygen concentration A system for controlling the air-fuel ratio has also been proposed (see, for example, Patent Document 1).

JP 2001-55952 A

  However, gas chromatography devices are expensive and require a long time for analysis. Therefore, the gas chromatography apparatus is not suitable for monitoring the fluctuation of the combustible gas composition in real time. Also for the oxygen sensor, it may take time to detect the oxygen concentration. Accordingly, the present invention provides a gas control system and a gas control method capable of easily and accurately measuring the calorific value of a combustible gas and appropriately controlling the mixing of the combustible gas and the combustion-supporting gas. Is one of the purposes.

  According to an aspect of the present invention, (a) a measurement mechanism that measures the value of the heat release coefficient or thermal conductivity of the combustible gas when the heat generating element generates heat at a plurality of heat generation temperatures; An equation storage device that stores a calorific value calculation formula having a heat dissipation coefficient or thermal conductivity as an independent variable and a calorific value as a dependent variable, and (c) a heat dissipation coefficient or thermal conductivity of a plurality of heat generation temperatures of the calorific value calculation formula. A calorific value calculation unit that calculates the calorific value of the combustible gas by substituting the heat dissipation coefficient or thermal conductivity value of the combustible gas for a plurality of exothermic temperatures into the independent variable, and (d) the exothermic heat of the combustible gas. A gas control system is provided that includes a control device that controls mixing of combustible gas and combustion-supporting gas based on the calculated value of the amount.

  According to another aspect of the present invention, (a) measuring the value of the heat release coefficient or thermal conductivity of the combustible gas when the heat generating element generates heat at a plurality of heat generation temperatures; and (b) the plurality of heat generation temperatures. Preparing a calorific value calculation formula with the heat dissipation coefficient or thermal conductivity as an independent variable and the calorific value as a dependent variable; and (c) independent of the heat dissipation coefficient or thermal conductivity for a plurality of heat generation temperatures in the calorific value calculation formula. Substituting into the variable the value of the heat release coefficient or thermal conductivity of the combustible gas for a plurality of heat generation temperatures, calculating the value of the heat generation amount of the combustible gas, and (d) the calculated value of the heat generation amount of the combustible gas Based on the above, there is provided a gas control method including controlling mixing of a combustible gas and a combustion-supporting gas.

  According to another aspect of the present invention, (a) a flow path through which a combustible gas flows, (b) a temperature measuring element disposed in the flow path, and (c) a plurality of heat generation elements disposed in the flow path. A heating element that generates heat at a temperature, (d) a value of an electrical signal from a temperature measuring element that depends on the temperature of the combustible gas, and a value of an electrical signal from the heating element at each of a plurality of heating temperatures are measured. A measurement module; and (e) a formula storage device for storing a calorific value calculation formula having the electric signal from the temperature measuring element and the electric signal from the heat generating element at a plurality of heat generation temperatures as independent variables and the calorific value as a dependent variable; (F) The value of the electric signal from the temperature measuring element and the value of the electric signal from the heating element are the independent variable of the electric signal from the temperature measuring element and the independent variable of the electric signal from the heating element of the calorific value calculation formula. And a calorific value calculation unit for calculating the calorific value of the combustible gas, g) based on the calculated value of the calorific value of the combustible gas, and combustible gas, a gas control system comprising a controller, the controlling the combustion-supporting gas, the mixture of is provided.

  According to another aspect of the present invention, (a) obtaining a value of an electrical signal from a temperature measuring element depending on the temperature of the combustible gas, and (b) providing a heating element in contact with the combustible gas with a plurality of heating temperatures. (C) obtaining values of electrical signals from the heating elements at each of a plurality of heating temperatures; (d) electrical signals from the temperature measuring elements and electricity from the heating elements at a plurality of heating temperatures. Preparing a calorific value calculation formula with the signal as an independent variable and the calorific value as a dependent variable; and (e) the independent variable of the electric signal from the temperature measuring element of the calorific value calculation formula and the electric signal from the heating element. Substituting the value of the electric signal from the temperature measuring element and the value of the electric signal from the heating element into the independent variable to calculate the value of the calorific value of the combustible gas, and (f) the calorific value of the combustible gas. Based on the calculated value, the mixture of combustible gas and supporting gas Gas control method comprising, and controlling is provided.

  According to the present invention, it is possible to provide a gas control system and a gas control method capable of easily and accurately measuring the calorific value of a combustible gas and appropriately controlling the mixing of the combustible gas and the combustion-supporting gas. is there.

1 is a perspective view of a microchip according to a first embodiment of the present invention. It is sectional drawing seen from the II-II direction of FIG. 1 of the microchip which concerns on the 1st Embodiment of this invention. It is a circuit diagram regarding the heat generating element which concerns on the 1st Embodiment of this invention. It is a circuit diagram regarding the temperature measuring element which concerns on the 1st Embodiment of this invention. It is a graph which shows the relationship between the heat_generation | fever temperature of the heat generating element which concerns on the 1st Embodiment of this invention, and the thermal radiation coefficient of gas. It is the 1st schematic diagram of the calorific value calculation formula creation system concerning a 1st embodiment of the present invention. It is the 2nd schematic diagram of the calorific value calculation formula creation system concerning a 1st embodiment of the present invention. It is a flowchart which shows the preparation method of the emitted-heat amount calculation formula which concerns on the 1st Embodiment of this invention. It is a mimetic diagram of the calorific value calculation system concerning a 1st embodiment of the present invention. It is a flowchart which shows the measuring method of the emitted-heat amount which concerns on the 1st Embodiment of this invention. It is a table | surface which shows the relationship between the composition of the sample mixed gas which concerns on the Example of the 1st Embodiment of this invention, and the emitted-heat amount. It is a graph which shows the calculated calorific value of the sample mixed gas concerning the example of the 1st embodiment of the present invention, and a true calorific value. It is a graph which shows the relationship between the true calorific value of the sample mixed gas which concerns on the Example of the 1st Embodiment of this invention, and the calculated calorific value. It is a schematic diagram of the gas control system which concerns on the 1st Embodiment of this invention. It is a schematic diagram of the calorific value calculation formula creation system according to the second embodiment of the present invention. It is a schematic diagram of the calorific value calculation system according to the second embodiment of the present invention. It is a schematic diagram of the gas control system which concerns on the 2nd Embodiment of this invention. It is a graph which shows the relationship between the thermal conductivity which concerns on the 2nd Embodiment of this invention, and a thermal radiation coefficient.

  Embodiments of the present invention will be described below. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, the drawings are schematic. Therefore, specific dimensions and the like should be determined in light of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

(First embodiment)
[Heat generation calculation formula creation system and calorific value calculation formula creation method]
First, a calorific value calculation formula creation system and a calorific value calculation formula creation method capable of creating a calorific value calculation formula used by the gas control system according to the first embodiment of the present invention will be described. The calorific value calculation formula creation system includes a microchip 8 shown in FIG. 1 which is a perspective view and FIG. 2 which is a cross-sectional view seen from the II-II direction. The microchip 8 includes a substrate 60 provided with a cavity 66, and an insulating film 65 disposed on the substrate 60 so as to cover the cavity 66. The thickness of the substrate 60 is, for example, 0.5 mm. The vertical and horizontal dimensions of the substrate 60 are, for example, about 1.5 mm. A portion of the insulating film 65 covering the cavity 66 forms a heat insulating diaphragm. Furthermore, the microchip 8 includes a heating element 61 provided in the diaphragm portion of the insulating film 65, a first temperature measuring element 62 and a second temperature measuring element 62 provided in the diaphragm portion of the insulating film 65 so as to sandwich the heating element 61. The temperature measuring element 63 and a heat retaining element 64 provided on the substrate 60 are provided.

  The heating element 61 is disposed at the center of the diaphragm portion of the insulating film 65 that covers the cavity 66. The heating element 61 is a resistor, for example, and generates heat when power is applied to heat the atmospheric gas in contact with the heating element 61. Each of the first temperature measuring element 62 and the second temperature measuring element 63 is a resistor, for example, and detects the gas temperature of the atmospheric gas before the heat generating element 61 generates heat. Note that the gas temperature may be detected using only one of the first temperature measuring element 62 and the second temperature measuring element 63. Alternatively, an average value of the gas temperature detected by the first temperature measuring element 62 and the gas temperature detected by the second temperature measuring element 63 may be adopted as the gas temperature. In the following, an example in which the average value of the gas temperatures detected by the first temperature measuring element 62 and the second temperature measuring element 63 is adopted as the gas temperature will be described, but the present invention is not limited to this.

The heat retaining element 64 is a resistor, for example, and generates heat when supplied with electric power, and keeps the temperature of the substrate 60 constant. As a material of the substrate 60, silicon (Si) or the like can be used. As a material of the insulating film 65, silicon oxide (SiO ₂ ) or the like can be used. The cavity 66 is formed by anisotropic etching or the like. Further, platinum (Pt) or the like can be used as the material of the heating element 61, the first temperature measuring element 62, the second temperature measuring element 63, and the heat retaining element 64, and can be formed by a lithography method or the like. .

As shown in FIG. 3, for example, a positive input terminal of an operational amplifier 170 is electrically connected to one end of the heating element 61, and the other end is grounded. A resistance element 161 is connected in parallel with the + input terminal and the output terminal of the operational amplifier 170. The negative input terminal of the operational amplifier 170 has a resistance element 162 and a resistance element 163 connected in series, a resistance element 163 and a resistance element 164 connected in series, and a resistance element 164 and a resistance connected in series. It is electrically connected to the element 165 or to the ground terminal of the resistance element 165. By appropriately determining the resistance value of each resistance element 162-165, for example, when a voltage Vin of 5.0 V is applied to one end of the resistance element 162, the resistance element 163 and the resistance element 162 have a voltage of 2.4 V, for example. Voltage V _L3 is generated. Further, a voltage V _{L2 of} 1.9 V, for example, is generated between the resistance element 164 and the resistance element 163, and a voltage V _L1 of, for example, 1.4 V is generated between the resistance element 165 and the resistance element 164.

  A switch SW1 is provided between the resistance element 162 and the resistance element 163 and between the negative input terminal of the operational amplifier, and between the resistive element 163 and the resistive element 164 and between the negative input terminal of the operational amplifier. Is provided with a switch SW2. Further, a switch SW3 is provided between the resistance element 164 and the resistance element 165 and between the negative input terminal of the operational amplifier, and between the ground terminal of the resistive element 165 and the negative input terminal of the operational amplifier. A switch SW4 is provided.

When a voltage V _L3 of 2.4 V is applied to the negative input terminal of the operational amplifier 170, only the switch SW1 is energized and the switches SW2, SW3, SW4 are disconnected. Of the operational amplifier 170 - When applying the voltage V _L2 of 1.9V to the input terminal, only the switch SW2 is turned on and the switches SW1, SW3, SW4 are disconnected. When a voltage V _L1 of 1.4 V is applied to the negative input terminal of the operational amplifier 170, only the switch SW3 is energized and the switches SW1, SW2, and SW4 are disconnected. When a voltage V _L0 of 0 V is applied to the negative input terminal of the operational amplifier 170, only the switch SW4 is energized and the switches SW1, SW2, and SW3 are disconnected. Therefore, either 0V or a three-stage voltage can be applied to the negative input terminal of the operational amplifier 170 by opening and closing the switches SW1, SW2, SW3, and SW4. Therefore, the applied voltage that determines the heat generation temperature of the heat generating element 61 can be set in three stages by opening and closing the switches SW1, SW2, SW3, and SW4.

The heating element 61 shown in FIGS. 1 and 2 changes its resistance value depending on the temperature. A heat producing temperature T _H of the heater element 61, the relationship between the resistance value R _H of the heater element 61 is given by the following equation (1).
R _H = R _STD × [1 + α (T _H -T _STD ) + β (T _H -T _STD ) ² ] (1)
Here, T _STD represents a standard temperature, for example, 20 ° C. R _STD represents a resistance value measured in advance at the standard temperature T _STD . α represents a first-order resistance temperature coefficient, and β represents a second-order resistance temperature coefficient. Further, the resistance value R _H of the heating element 61 is given by the following equation (2) from the driving power P _H of the heating element 61 and the energization current I _H of the heating element 61.
R _H = P _H / I _H ² (2)
Alternatively, the resistance value R _H of the heating element 61 is given by the following equation (3) from the voltage V _H applied to the heating element 61 and the energization current I _H of the heating element 61.
R _H = V _H / I _H (3)

Here, the heat generation temperature _TH of the heat generating element 61 is stabilized when the heat generating element 61 and the atmospheric gas are in thermal equilibrium. The thermally balanced state refers to a state in which the heat generation of the heating element 61 and the heat dissipation from the heating element 61 to the atmospheric gas are balanced. As shown in the following equation (4), the driving power P _H of the heating element 61 in the equilibrium state is divided by the difference between the heating temperature T _H of the heating element 61 and the temperature T _O of the atmosphere gas, thereby releasing the heat of the atmosphere gas. The coefficient M _O is obtained. The unit of the heat dissipation coefficient M _O is, for example, W / ° C.
M _O = P _H / (T _H -T _O ) (4)

And current I _H flowing in the heater element 61, the driving power P _H or the voltage V _H, capable of measuring, (1) to (3) heat producing temperature T _H of the heater element 61 can be calculated from the equation. Further, the temperature T _{O of the} atmospheric gas can be measured by the first temperature measuring element 62 and the second temperature measuring element 63 shown in FIG. Thus, by using the microchip 8 shown in Figs. 1 and 2, the radiation coefficient M _O of the atmosphere gas can be calculated.

  The microchip 8 is fixed to a chamber or the like filled with atmospheric gas via a heat insulating member 18 disposed on the bottom surface of the microchip 8. By fixing the microchip 8 to the chamber or the like via the heat insulating member 18, the temperature of the microchip 8 becomes less susceptible to the temperature fluctuation of the inner wall of the chamber or the like. The heat insulating member 18 is made of glass or the like, and the thermal conductivity is, for example, 1.0 W / (m · K) or less.

  As shown in FIG. 4, for example, a negative input terminal of an operational amplifier 270 is electrically connected to one end of the first temperature measuring element 62, and the other end is grounded. In addition, a resistance element 261 is connected in parallel with the negative input terminal and the output terminal of the operational amplifier 270. The positive input terminal of the operational amplifier 270 is electrically connected between the resistance element 264 and the resistance element 265 connected in series. Thereby, a weak voltage of about 0.3 V is applied to the first temperature measuring element 62.

Note that, by keeping the temperature of the substrate 60 constant by the heat retaining element 64, the temperature of the ambient gas in the vicinity of the microchip 8 before the heat generating element 61 generates heat approximates the constant temperature of the substrate 60. For this reason, fluctuations in the temperature of the atmospheric gas before the heat generating element 61 generates heat are suppressed. By temperature variation further heated by the heating element 61 to the atmosphere gas is once suppressed, it is possible to calculate the radiation coefficient M _I with high accuracy.

Here, it is assumed that the atmospheric gas is a mixed gas, and the mixed gas is composed of four types of gas components: gas A, gas B, gas C, and gas D. The sum of the volume ratio V _{A of} the gas _A , the volume ratio V _{B of} the gas _B , the volume ratio V _{C of} the gas _C , and the volume ratio V _D of the gas D is 1 as given by the following equation (5). .
V _A + V _B + V _C + V _D = 1 (5)

The calorific value per unit volume of gas A is K _A , the calorific value per unit volume of gas B is K _B , the calorific value per unit volume of gas C is K _C , and the calorific value per unit volume of gas D is Is K _D , the calorific value Q per unit volume of the mixed gas is given by the sum of the volume ratio of each gas component multiplied by the calorific value per unit volume of each gas component. Therefore, the calorific value Q per unit volume of the mixed gas is given by the following equation (6). The unit of the calorific value per unit volume is, for example, MJ / m ³ .
Q = K _A × V _A + K _B × V _B + K _C × V _C + K _D × V _D ... (6)

Moreover, the radiation coefficient M _A gas A, the radiation coefficient of gas B M _B, when the radiation coefficient of gas C M _C, the radiation coefficient of the gas D and M _D, the radiation coefficient M _I of the mixed gas, the It is given as the sum of the volume fraction of the gas component multiplied by the heat dissipation coefficient of each gas component. Therefore, the heat dissipation coefficient M _I of the mixed gas is given by the following equation (7).
M _I = M _A × V _A + M _B × V _B + M _C × V _C + M _D × V _D ... (7)

Further, since the radiation coefficient of gas depends on the heating temperature T _H of the heater element 61, the radiation coefficient M _I of the mixed gas, as a function of the heat producing temperature T _H of the heater element 61 is given by the following equation (8).
M _I (T _H ) = M _A (T _H ) × V _A + M _B (T _H ) × V _B + M _C (T _H ) × V _C + M _D (T _H ) × V _D・ ・ ・ ( 8)

Therefore, the heat release coefficient M _I (T _H1 ) of the mixed gas when the heat generation temperature of the heat generating element 61 is T _H1 is given by the following equation (9). Further, the heat release coefficient M _I (T _H2 ) of the mixed gas when the heat generation temperature of the heat generating element 61 is T _H2 is given by the following equation (10), and the mixture gas when the heat generation temperature of the heat generating element 61 is T _H3 is given. The heat radiation coefficient M _I (T _H3 ) is given by the following equation (11). The exothermic temperature T _H1 , the exothermic temperature T _H2 , and the exothermic temperature T _H3 are different temperatures.
M _I (T _H1 ) = M _A (T _H1 ) × V _A + M _B (T _H1 ) × V _B + M _C (T _H1 ) × V _C + M _D (T _H1 ) × V _D・ ・ ・ ( 9)
M _I (T _H2 ) = M _A (T _H2 ) × V _A + M _B (T _H2 ) × V _B + M _C (T _H2 ) × V _C + M _D (T _H2 ) × V _D・ ・ ・ ( Ten)
M _I (T _H3 ) = M _A (T _H3 ) × V _A + M _B (T _H3 ) × V _B + M _C (T _H3 ) × V _C + M _D (T _H3 ) × V _D・ ・ ・ ( 11)

Here, the heat dissipation coefficients M _A (T _H ), M _B (T _H ), M _C (T _H ), and M _D (T _H ) of each gas component are nonlinear with respect to the heat generation temperature T _H of the heat generating element 61. (9) to (11) have a linearly independent relationship. Further, the heat dissipation coefficients M _A (T _H ), M _B (T _H ), M _C (T _H ), and M _D (T _H ) of each gas component have linearity with respect to the heat generation temperature T _H of the heat generating element 61. Even if it has, the rate of change of the radiation coefficient M _A (T _H ), M _B (T _H ), M _C (T _H ), M _D (T _H ) of each gas component with respect to the heat generation temperature T _H of the heating element 61 When they are different, the above equations (9) to (11) have a linearly independent relationship. Further, when the equations (9) to (11) have a linearly independent relationship, the equations (5) and (9) to (11) have a linearly independent relationship.

FIG. 5 shows the relationship between the heat release coefficient of the heating element 61 and the heat release coefficient of methane (CH ₄ ), propane (C ₃ H ₈ ), nitrogen (N ₂ ), and carbon dioxide (CO ₂ ) contained in natural gas. It is a graph. The heat release coefficient of each gas component of methane (CH ₄ ), propane (C ₃ H ₈ ), nitrogen (N ₂ ), and carbon dioxide (CO ₂ ) has linearity with respect to the heat generation temperature of the heat generating element 61. . However, the rate of change of the heat dissipation coefficient with respect to the heat generation temperature of the heat generating element 61 is different for each of methane (CH ₄ ), propane (C ₃ H ₈ ), nitrogen (N ₂ ), and carbon dioxide (CO ₂ ). Therefore, when the gas components constituting the mixed gas are methane (CH ₄ ), propane (C ₃ H ₈ ), nitrogen (N ₂ ), and carbon dioxide (CO ₂ ), the above (9) to (11 ) Has a linearly independent relationship.

The heat release coefficients M _A (T _H1 ), M _B (T _H1 ), M _C (T _H1 ), M _D (T _H1 ), M _A (T _H2 ) of the gas components in the equations (9) to (11) , M _B (T _H2 ), M _C (T _H2 ), M _D (T _H2 ), M _A (T _H3 ), M _B (T _H3 ), M _C (T _H3 ), M _D (T _H3 ) The value can be obtained in advance by measurement or the like. Therefore, when the simultaneous equations of the equations (5) and (9) to (11) are solved, the volume ratio V _{A of} the gas _A , the volume ratio V _{B of} the gas _B , the volume ratio V _{C of} the gas _C , and the gas D Each of the volume ratios V _D is expressed as a function of the heat release coefficient M _I (T _H1 ), M _I (T _H2 ), M _I (T _H3 ) of the mixed gas as shown in the following equations (12) to (15). Given. In the following equations (12) to (15), n is a natural number and f _n is a symbol representing a function.
V _A = f ₁ [M _I (T _H1 ), M _I (T _H2 ), M _I (T _H3 )] (12)
V _B = f ₂ [M _I (T _H1 ), M _I (T _H2 ), M _I (T _H3 )] (13)
V _C = f ₃ [M _I (T _H1 ), M _I (T _H2 ), M _I (T _H3 )] (14)
V _D = f ₄ [M _I (T _H1 ), M _I (T _H2 ), M _I (T _H3 )] (15)

Here, the following equation (16) is obtained by substituting the equations (16) to (19) into the above equation (6).
Q = K _A × V _A + K _B × V _B + K _C × V _C + K _D × V _D
= K _A × f ₁ [M _I (T _H1 ), M _I (T _H2 ), M _I (T _H3 )]
+ K _B × f ₂ [M _I (T _H1 ), M _I (T _H2 ), M _I (T _H3 )]
+ K _C × f ₃ [M _I (T _H1 ), M _I (T _H2 ), M _I (T _H3 )]
+ K _D × f ₄ [M _I (T _H1 ), M _I (T _H2 ), M _I (T _H3 )] (16)

As is clear from the above equation (16), the calorific value Q per unit volume of the mixed gas is the heat dissipation coefficient M _I of the mixed gas when the heating temperature of the heating element 61 is T _H1 , T _H2 , T _H3. T _H1 ), M _I (T _H2 ), and M _I (T _H3 ) are given as equations. Therefore, the calorific value Q of the mixed gas is given by the following equation (17), where g is a symbol representing a function.
Q = g [M _I (T _H1 ), M _I (T _H2 ), M _I (T _H3 )] (17)

Therefore, if the above equation (17) is obtained in advance for a mixed gas composed of gas A, gas B, gas C, and gas D, the volume ratio V _A of gas _A , the volume ratio V _B of gas _B , and the gas C The inventors have found that the calorific value Q per unit volume of the gas to be inspected with unknown volume ratio V _C and volume ratio V _{D of} gas D can be easily calculated. Specifically, the radiation coefficient M _I of the mixed gas to be examined when the heat producing temperature of the heater element 61 is _{T H1, T H2, T H3} (T H1), M I (T H2), M I (T H3 ) And substituting it into the equation (17) makes it possible to uniquely determine the calorific value Q of the mixed gas to be inspected.

The gas components of the mixed gas are not limited to four types. For example, when the mixed gas is composed of n types of gas components, first, at least n−1 types of heat generation temperatures T _H1 , T _H2 , T _H3,. radiation coefficient of the mixed gas with respect to _{T Hn-1 M I (T} H1), M I (T H2), M I (T H3), ···, the equation as a variable M _I (T _Hn-1) previously get. Then, n-1 kinds of the heating temperatures T _H1, T _H2, T _H3 of the heater element 61, ..., for T _Hn-1, each of the volume fraction of n kinds of gas components is unknown mixed gas to be examined By measuring the heat dissipation coefficients M _I (T _H1 ), M _I (T _H2 ), M _I (T _H3 ),..., M _I (T _Hn-1 ) The calorific value Q per unit volume of the target mixed gas can be uniquely determined.
Q = g [M _I (T _H1 ), M _I (T _H2 ), M _I (T _H3 ), ..., M _I (T _Hn-1 )] ... (18)

However, the mixed gas, methane (CH ₄₎ as a gas component in addition to the propane (C ₃ H _8), a j is a natural number, methane (CH ₄₎ and other than propane (C ₃ H ₈₎ alkane (C _j H _{2j + 2} ), alkanes other than methane (CH ₄ ) and propane (C ₃ H ₈ ) (C _j H _{2j + 2} ), and mixtures of methane (CH ₄ ) and propane (C ₃ H ₈ ) This does not affect the calculation of equation (18). For example, ethane (C ₂ H ₆ ), butane (C ₄ H ₁₀ ), pentane (C ₅ H ₁₂ ), and hexane (C ₆ H ₁₄ ) are respectively represented by the following formulas (19) to (22): The equation (18) may be calculated by regarding the mixture as methane (CH ₄ ) and propane (C ₃ H ₈ ) multiplied by a predetermined coefficient.
C ₂ H ₆ = 0.5 CH ₄ + 0.5 C ₃ H ₈ ... (19)
C ₄ H ₁₀ = -0.5 CH ₄ + 1.5 C ₃ H ₈ ... (20)
C ₅ H ₁₂ = -1.0 CH ₄ + 2.0 C ₃ H ₈ ... (21)
C ₆ H ₁₄ = -1.5 CH ₄ + 2.5 C ₃ H ₈ ... (22)

Accordingly, the z as a natural number, a mixed gas consisting of n kinds of gas components methane (CH ₄₎ as a gas component in addition to the propane (C ₃ H _8), methane (CH ₄₎ and propane (C ₃ H ₈ ) Other than z types of alkanes (C _j H _{2j + 2} ), an equation having at least the heat release coefficient M _I of the mixed gas at nz−1 types of exothermic temperatures may be obtained.

In addition, when the type of the gas component of the mixed gas used in the calculation of the equation (18) is the same as the type of the gas component of the mixed gas to be inspected whose calorific value Q per unit volume is unknown, Of course, the equation (18) can be used to calculate the calorific value Q. Furthermore, when the inspection target mixed gas is composed of less than n kinds of gas components and less than n kinds of gas components are included in the mixed gas used in the calculation of equation (18), Equation (18) can be used. For example, the mixed gas used in the calculation of the equation (18) includes four types of gas components, methane (CH ₄ ), propane (C ₃ H ₈ ), nitrogen (N ₂ ), and carbon dioxide (CO ₂ ). In some cases, the mixed gas to be inspected does not contain nitrogen (N ₂ ) but contains only three kinds of gas components, methane (CH ₄ ), propane (C ₃ H ₈ ), and carbon dioxide (CO ₂ ). The equation (18) can be used to calculate the calorific value Q of the inspection target mixed gas.

Further, when the mixed gas used in the calculation of the equation (18) contains methane (CH ₄ ) and propane (C ₃ H ₈ ) as gas components, the inspection target mixed gas is used in the calculation of the equation (18). Even if the alkane (C _j H _{2j + 2} ) not contained in the mixed gas is contained, the formula (18) can be used. This is because, as described above, the methane (CH ₄₎ and propane (C ₃ H ₈₎ other than the alkane _{(C j H 2j + 2)} , a mixture of methane (CH ₄₎ and propane (C ₃ H ₈₎ Even if it considers, it is because it does not affect calculation of the emitted-heat amount Q per unit volume using (18) Formula.

Here, the calorific value calculation formula creation system 20A shown in FIG. 6 includes a chamber 101 filled with a sample mixed gas whose calorific value Q is known, the heating element 61 shown in FIG. 1 and FIG. A measurement mechanism 10 shown in FIG. 6 is provided that measures the values of a plurality of heat release coefficients M _I of the sample mixed gas using the temperature element 62 and the second temperature measurement element 63. Furthermore, the calorific value calculation formula creation system 20A is configured to generate a gas corresponding to a plurality of heating temperatures of the heating element 61 based on a known calorific value Q of the sample mixed gas and a plurality of heat dissipation coefficients M _I of the sample mixed gas. Is provided with a formula creation module 302 that creates a calorific value calculation formula with the heat dissipation coefficient M _I of the gas as an independent variable and the calorific value Q of the gas as a dependent variable. The sample mixed gas includes a plurality of types of gas components.

  The measurement mechanism 10 includes the microchip 8 described with reference to FIGS. 1 and 2 disposed in a chamber 101 into which a sample mixed gas is injected. The microchip 8 is disposed in the chamber 101 via the heat insulating member 18. The chamber 101 is connected to a flow path 102 for sending the sample mixed gas to the chamber 101 and a flow path 103 for discharging the sample mixed gas from the chamber 101 to the outside.

  When four types of sample mixed gases with different calorific values Q are used, as shown in FIG. 7, the first gas cylinder 50A for storing the first sample mixed gas and the second sample mixed gas for storing the second sample mixed gas are used. A second gas cylinder 50B, a third gas cylinder 50C for storing a third sample mixed gas, and a fourth gas cylinder 50D for storing a fourth sample mixed gas are prepared. In the first gas cylinder 50A, a first gas pressure regulator 31A for obtaining a first sample mixed gas adjusted to a low pressure such as 0.2 MPa from the first gas cylinder 50A via a flow path 91A. Is connected. In addition, a first flow rate control device 32A is connected to the first gas pressure regulator 31A via a flow path 92A. The first flow rate control device 32A controls the flow rate of the first sample mixed gas sent to the calorific value calculation formula creation system 20A via the flow path 92A and the flow path 102.

  A second gas pressure regulator 31B is connected to the second gas cylinder 50B via a flow path 91B. In addition, a second flow rate control device 32B is connected to the second gas pressure regulator 31B via a flow path 92B. The second flow rate control device 32B controls the flow rate of the second sample mixed gas sent to the calorific value calculation formula creation system 20A via the flow paths 92B, 93, 102.

  A third gas pressure regulator 31C is connected to the third gas cylinder 50C via a flow path 91C. In addition, a third flow rate control device 32C is connected to the third gas pressure regulator 31C via a flow path 92C. The third flow rate control device 32C controls the flow rate of the third sample mixed gas sent to the calorific value calculation formula creation system 20A via the flow paths 92C, 93, and 102.

  A fourth gas pressure regulator 31D is connected to the fourth gas cylinder 50D via a flow path 91D. In addition, a fourth flow rate control device 32D is connected to the fourth gas pressure regulator 31D via a flow path 92D. The fourth flow rate control device 32D controls the flow rate of the fourth sample mixed gas sent to the calorific value calculation formula creation system 20A via the flow paths 92D, 93, and 102.

Each of the first to fourth sample mixed gases is natural gas having a known calorific value Q, for example. Each of the first to fourth sample mixed gases includes four kinds of gas components, for example, methane (CH ₄ ), propane (C ₃ H ₈ ), nitrogen (N ₂ ), and carbon dioxide (CO ₂ ).

After the first sample mixed gas is filled in the chamber 101, the first temperature measuring element 62 and the second temperature measuring element 63 shown in FIGS. 1 and 2 of the microchip 8 are before the heating element 61 generates heat. The temperature T _I of the first sample mixed gas is detected. Thereafter, the heater element 61 is provided with a driving power P _H from the driving circuit 303 shown in FIG. By applies driving power P _H, the heater element 61 shown in FIGS. 1 and 2, for example, 100 ° C., to heat at 0.99 ° C., and 200 ° C..

After the first sample mixed gas is removed from the chamber 101 shown in FIG. 6, the chamber 101 is sequentially filled with the second to fourth sample mixed gases. After each of the second to fourth sample mixed gas is filled into the chamber 101, the microchip 8 detects the second to the respective temperatures T _I of the fourth sample mixed gas. Further, the heater element 61 shown in Figures 1 and 2 are given the driving power P _H, 100 ° C., to heat at 0.99 ° C., and 200 ° C..

In addition, when each sample mixed gas contains n types of gas components, the heating element 61 shown in FIGS. 1 and 2 of the microchip 8 is caused to generate heat at at least n−1 different types of heating temperatures. However, as described above, methane (CH ₄₎ and propane (C ₃ H ₈₎ other than the alkane (C _j H _{2j + 2)} is regarded as a mixture of methane (CH ₄₎ and propane (C ₃ H ₈₎ sell. Accordingly, a sample mixed gas composed of n kinds of gas components, where z is a natural number, is added to methane (CH ₄ ) and propane (C ₃ H ₈ ) as gas components, and z kinds of alkanes (C _j H _{2j + 2} ). When the heat generating element 61 is included, the heat generating element 61 is caused to generate heat at at least nz-1 different heat generation temperatures.

The measurement mechanism 10 shown in FIG. 6 further includes a heat dissipation coefficient calculation module 301 connected to the microchip 8. The heat dissipation coefficient calculation module 301 uses the first driving power _PH1 of the heating element 61 of the microchip 8 shown in FIGS. 1 and 2 as the first heating temperature of the heating element 61 as shown in the above equation (4). Divide by the difference between T _H (here, 100 ° C.) and the temperature T _I of each of the first to fourth sample mixed gases. Thus, the value of each of the radiation coefficient M _I of the heating temperature is 100 ° C. of the heater element 61 in thermal equilibrium with the first through fourth sample mixed gas is calculated.

Further, the heat dissipation coefficient calculation module 301 shown in FIG. 6 uses the second driving power P _H2 of the heating element 61 shown in FIGS. 1 and 2 of the microchip 8 as the second heating temperature T _H of the heating element 61 (here Then, it is divided by the difference between the temperature T _I of each of the first to fourth sample mixed gases. Thus, the value of each of the radiation coefficient M _I of the heating temperature is 0.99 ° C. of the heating element 61 and thermally equilibrium first through fourth sample mixed gas is calculated.

Furthermore, the heat dissipation coefficient calculation module 301 shown in FIG. 6 uses the third drive power P _H3 of the heating element 61 shown in FIGS. 1 and 2 of the microchip 8 as the third heating temperature T _H of the heating element 61 (here Then, it is divided by the difference between the temperature T _I of each of the first to fourth sample mixed gases. Thus, the value of each of the radiation coefficient M _I of the heating temperature is 200 ° C. of the heater element 61 in thermal equilibrium with the first through fourth sample mixed gas is calculated.

The calorific value calculation formula creation system 20 </ b> A shown in FIG. 6 further includes a heat dissipation coefficient storage device 401 connected to the CPU 300. Radiation coefficient calculation module 301 stores the calculated value of the radiation coefficients M _I in the radiation coefficient storage device 401.

For example, the formula creation module 302 is configured to calculate the known calorific value Q of the first to fourth sample mixed gases and the heat dissipation coefficient of the first to fourth sample mixed gases when the heating temperature of the heating element 61 is 100 ° C. The value of M _I, the value of the heat dissipation coefficient M _I of the first to fourth sample mixed gases when the heating temperature of the heating element 61 is 150 ° C., and the first when the heating temperature of the heating element 61 is 200 ° C. To the value of the heat dissipation coefficient M _I of the fourth sample mixed gas. Formula creation module 302 further based on the plurality of values of the collected calorific value Q and radiation coefficients M _I, by multivariate analysis, the radiation coefficient MI when the heat producing temperature of the heater element 61 is 100 ° C. M _I, the heater element 61 the radiation coefficient MI when the heat producing temperature is 0.99 ° C. M _I, and the radiation coefficient M _I when the heat producing temperature of the heater element 61 is 200 ° C. as independent variables, calculating the calorific value calculation formula to the calorific value Q as a dependent variable To do.

  Note that “multivariate analysis” refers to A.I. J Smol and B.M. In support vector regression, multiple regression analysis, and Japanese Patent Application Laid-Open No. 5-141999, disclosed in Scholkopf's “A Tutor on Support Vector Regression” (NeuroCOLt Technical Report (NC-TR-98-030), 1998). Includes the disclosed fuzzy quantification theory class II. The heat dissipation coefficient calculation module 301 and the formula creation module 302 are included in a central processing unit (CPU) 300.

  The calorific value calculation formula creation system 20 </ b> A further includes a formula storage device 402 connected to the CPU 300. The formula storage device 402 stores the calorific value calculation formula created by the formula creation module 302. Further, an input device 312 and an output device 313 are connected to the CPU 300. As the input device 312, for example, a keyboard and a pointing device such as a mouse can be used. As the output device 313, an image display device such as a liquid crystal display and a monitor, a printer, and the like can be used.

  Next, a method for creating a calorific value calculation formula will be described using the flowchart shown in FIG. In the following example, a case will be described in which first to fourth sample mixed gases are prepared and the heating element 61 of the microchip 8 shown in FIG. 6 generates heat at 100 ° C., 150 ° C., and 200 ° C.

(A) In step S100, with the valves of the second to fourth flow control devices 32B-32D shown in FIG. 7 closed, the valve of the first flow control device 32A is opened and placed in the chamber 101 shown in FIG. A first sample mixed gas is introduced. In step S101, the first temperature measuring element 62 and the second temperature measuring element 63 shown in FIGS. 1 and 2 detect the temperature T _I of the first sample mixed gas. Thereafter, the driving circuit 303 shown in FIG. 6 gives a first driving power P _H1 to the heater element 61 shown in Figures 1 and 2 of the microchip 8, thereby heating the heating element 61 at 100 ° C.. Additionally, the radiation coefficient calculation module 301 shown in FIG. 6, the heat generation temperature of the heater element 61 to calculate the radiation coefficient M _I of the first sample mixed gas when the 100 ° C.. Then, the radiation coefficient calculation module 301, the heat generation temperature of the heater element 61 to store the value of the radiation coefficient M _I when the 100 ° C. in the radiation coefficient storage device 401. Thereafter, the drive circuit 303 stops providing the first drive power P _H1 to the heating element 61.

(B) In step S102, the drive circuit 303 determines whether or not the switching of the heat generation temperature of the heat generating element 61 shown in FIGS. 1 and 2 has been completed. When the switching to the heat generation temperature of 150 ° C. and the heat generation temperature of 200 ° C. is not completed, the process returns to step S101, and the drive circuit 303 shown in FIG. 6 generates heat at 150 ° C. in the heat generating element 61 shown in FIGS. Let The heat dissipation coefficient calculation module 301 shown in FIG. 6 calculates the value of the heat dissipation coefficient M _I of the first sample mixed gas when the heat generation temperature of the heat generating element 61 is 150 ° C., and stores it in the heat dissipation coefficient storage device 401. Thereafter, the drive circuit 303 stops the supply of drive power to the heating element 61.

(C) In step S102, it is determined whether or not switching of the heat generation temperature of the heat generating element 61 shown in FIGS. 1 and 2 is completed. When the switching to the heat generation temperature of 200 ° C. is not completed, the process returns to step S101, and the drive circuit 303 shown in FIG. 6 causes the heat generating element 61 shown in FIGS. The heat dissipation coefficient calculation module 301 shown in FIG. 6 calculates the value of the heat dissipation coefficient M _I of the first sample mixed gas when the heat generation temperature of the heat generating element 61 is 200 ° C., and stores it in the heat dissipation coefficient storage device 401. Thereafter, the drive circuit 303 stops the supply of drive power to the heating element 61.

  (D) When the switching of the heat generation temperature of the heat generating element 61 is completed, the process proceeds from step S102 to step S103. In step S103, it is determined whether or not the sample mixed gas has been switched. If switching to the second to fourth sample mixed gases has not been completed, the process returns to step S100. In step S100, the first flow control device 32A shown in FIG. 7 is closed, the valves of the second flow control device 32B are opened while the valves of the third to fourth flow control devices 32C-32D are closed, and FIG. A second sample mixed gas is introduced into the chamber 101 shown in FIG.

(E) Similar to the first sample mixed gas, the loop of step S101 to step S102 is repeated. First, the value of the temperature T _I of the second sample mixed gas is measured. In addition, the heat dissipation coefficient calculation module 301 has a value of the heat dissipation coefficient M _I of the second sample mixed gas when the heat generation temperature of the heat generating element 61 is 100 ° C., and a second value when the heat generation temperature of the heat generating element 61 is 150 ° C. sample mixed radiation coefficient M _I of the gas, and the heat generation temperature of the heater element 61 to calculate the radiation coefficient M _I of the second sample mixed gas when the 200 ° C.. Further the radiation coefficient calculation module 301 stores the calculated value of the radiation coefficients M _I in the radiation coefficient storage device 401.

(F) Thereafter, the loop from step S100 to step S103 is repeated. As a result, the value of the heat dissipation coefficient M _I of the third sample mixed gas when the heating element 61 has a heating temperature of 100 ° C., 150 ° C., and 200 ° C. and the heating temperature of the heating element 61 are 100 ° C. and 150 ° C. The value of the heat dissipation coefficient M _I of the fourth sample mixed gas in each case of 200 ° C. is stored in the heat dissipation coefficient storage device 401. In step S104, the value of the known calorific value Q of the first sample mixed gas, the known calorific value Q of the second sample mixed gas, and the third sample mixed gas are transferred from the input device 312 to the formula creating module 302. The known calorific value Q and the known calorific value Q of the fourth sample mixed gas are input. In addition, the formula creation module 302 receives the heat dissipation coefficient M _I of the first to fourth sample mixed gases from the heat dissipation coefficient storage device 401 when the heat generation temperature of the heating element 61 is 100 ° C., 150 ° C., and 200 ° C., respectively. Read the value.

(G) In step S105, the value of the calorific value Q of the first to fourth sample mixed gases and the first to fourth in each case where the heating temperature of the heating element 61 is 100 ° C., 150 ° C., and 200 ° C. Based on the value of the heat release coefficient M _I of the sample mixed gas, the formula creation module 302 performs multiple regression analysis. By multiple regression analysis, the formula creation module 302, the radiation coefficient M _I when the heat producing temperature of the heater element 61 is 100 ° C., the heat producing temperature of the heater element 61 is in the case of 0.99 ° C. the radiation coefficient M _I, and of the heater element 61 When the heat generation temperature is 200 ° C., the heat generation coefficient M _I is set as an independent variable, and the heat generation amount calculation formula using the heat generation amount Q as a dependent variable is calculated. Thereafter, in step S106, the formula creation module 302 stores the created calorific value calculation formula in the formula storage device 402, and ends the creation of the calorific value calculation formula.

  The calorific value calculation formula capable of uniquely calculating the calorific value Q of the measurement target mixed gas is created as described above.

[Heat generation calculation system and heat generation calculation method]
Next, a heat generation amount calculation system provided in the gas control system according to the first embodiment of the present invention and a heat generation amount calculation method using the system will be described. As shown in FIG. 9, the calorific value calculation system 21A includes a chamber 101 filled with a combustible gas that is a measurement target mixed gas whose calorific value Q is unknown, and a heating element 61 shown in FIG. 1 and FIG. comprising using the first temperature measurement element 62 and the second temperature measurement element 63, the measuring mechanism 10 shown in FIG. 9 for measuring the value of a plurality of radiation coefficients M _I of the combustible gas. Furthermore, the calorific value calculation system 21A includes a formula storage device 402 that stores a calorific value calculation formula having the heat dissipation coefficient M _I of the gas for a plurality of heat generation temperatures of the heat generating element 61 as an independent variable and the calorific value Q as a dependent variable; Substituting the value of the heat dissipation coefficient M _I of the combustible gas for the plurality of heat generation temperatures of the heating element 61 into the independent variable of the gas heat dissipation coefficient M _I for the plurality of heat generation temperatures of the heat generation element 61 included in the calorific value calculation formula, A calorific value calculation module 305 that calculates the calorific value Q of the combustible gas.

The formula storage device 402 is prepared by the method shown in FIG. 8, for example, and the gas heat dissipation coefficient M _I when the heating temperature of the heating element 61 is 100 ° C. and the gas when the heating temperature of the heating element 61 is 150 ° C. to save the radiation coefficient M _I of the radiation coefficient M _I of the gas when the heat producing temperature of 200 ° C. of the heater element 61, the heat generation amount calculation formula as an independent variable.

The chamber 101 shown in FIG. 9 has a calorific value Q including, for example, methane (CH ₄ ), propane (C ₃ H ₈ ), nitrogen (N ₂ ), and carbon dioxide (CO ₂ ) at an unknown volume ratio. Unknown natural gas is introduced as a combustible gas. The first temperature measuring element 62 and the second temperature measuring element 63 of the microchip 8 shown in FIGS. 1 and 2 detect the temperature T _I of the combustible gas before the heat generating element 61 generates heat. Thereafter, the heater element 61 is provided with a driving power P _H from the driving circuit 303 shown in FIG. By applies driving power P _H, the heater element 61 shown in FIGS. 1 and 2, 100 ° C., to heat at 0.99 ° C., and 200 ° C..

The heat radiation coefficient calculation module 301 shown in FIG. 9 performs the heat radiation coefficient M _{I of the} combustible gas that is in thermal equilibrium with the heat generating element 61 that generates heat at a heat generation temperature of 100 ° C. according to the method described in the above equations (1) to (4). Is calculated. Further, the heat dissipation coefficient calculation module 301 is thermally connected to the value of the heat dissipation coefficient M _I of the combustible gas that is in thermal equilibrium with the heat generating element 61 that generates heat at a heat generation temperature of 150 ° C. and the heat generation element 61 that generates heat at a heat generation temperature of 200 ° C. The value of the heat release coefficient M _I of the combustible gas that is in equilibrium with is calculated. Radiation coefficient calculation module 301 stores the calculated value of the radiation coefficients M _I in the radiation coefficient storage device 401.

Calorific value calculation module 305, the independent variable of the radiation coefficients M _I of the calorific value calculation formula of the gas, and substitutes the value of the radiation coefficients M _I of the combustible gas, and calculates the value of the calorific value Q of the combustible gas. A heat generation amount storage device 403 is further connected to the CPU 300. The calorific value storage device 403 stores the calorific value Q of the combustible gas calculated by the calorific value calculation module 305. The other components of the heat generation amount calculation system 21A are the same as those of the heat generation amount calculation formula creation system 20A described with reference to FIG.

  Next, a method for measuring the calorific value will be described with reference to the flowchart shown in FIG. In the following example, the case where the heating element 61 of the microchip 8 shown in FIG. 9 generates heat at 100 ° C., 150 ° C. and 200 ° C. will be described.

(A) In step S200, a combustible gas is introduced into the chamber 101 shown in FIG. Next, in step S201, the first temperature measuring element 62 and the second temperature measuring element 63 of the microchip 8 shown in FIGS. 1 and 2 are set to the temperature T _I of the combustible gas before the heating element 61 generates heat. Is detected. Thereafter, the driving circuit 303 shown in FIG. 9 gives a first driving power P _H1 to the heater element 61 shown in Figures 1 and 2 of the microchip 8, thereby heating the heating element 61 at 100 ° C.. Radiation coefficient calculation module 301 shown in FIG. 9 calculates the radiation coefficient M _I of the combustible gas at the heat producing temperature of 100 ° C.. Additionally, the radiation coefficient calculation module 301, the heat generation temperature of the heater element 61 to store the value of the radiation coefficient M _I of the combustible gas in the case of 100 ° C. to the heat radiation coefficient storage device 401. Thereafter, the drive circuit 303 stops providing the first drive power P _H1 to the heating element 61.

(B) In step S202, the drive circuit 303 shown in FIG. 9 determines whether the switching of the heat generation temperature of the heat generating element 61 shown in FIGS. 1 and 2 is completed. When the switching to the heat generation temperature of 150 ° C. and the heat generation temperature of 200 ° C. is not completed, the process returns to step S201, and the drive circuit 303 shown in FIG. 9 generates the heat generation element 61 shown in FIGS. Let Radiation coefficient calculation module 301 shown in FIG. 9, the heat generation temperature of the heater element 61 calculates the radiation coefficient M _I of the combustible gas in the case of 0.99 ° C., is stored in the radiation coefficient storage device 401. Thereafter, the drive circuit 303 stops the supply of drive power to the heating element 61.

(C) In step S202, it is determined whether or not switching of the heat generation temperature of the heat generating element 61 shown in FIGS. 1 and 2 is completed. If the switching to the heat generation temperature of 200 ° C. has not been completed, the process returns to step S201, and the drive circuit 303 shown in FIG. 9 causes the heat generating element 61 shown in FIGS. Radiation coefficient calculation module 301 shown in FIG. 9, the heat generation temperature of the heater element 61 calculates the radiation coefficient M _I of the combustible gas in the case of 200 ° C., is stored in the radiation coefficient storage device 401. Thereafter, the drive circuit 303 stops the supply of drive power to the heating element 61.

(D) When the switching of the heat generation temperature of the heat generating element 61 is completed, the process proceeds from step S202 to step S203. In step S203, the calorific value calculation module 305 shown in FIG. 9 uses, as an independent variable, the gas heat dissipation coefficient M _I when the heating temperature of the heating element 61 is 100 ° C., 150 ° C., and 200 ° C. from the formula storage device 402. Read out the calorific value calculation formula. Further, the calorific value calculation module 305, from the radiation coefficient storing device 401, heat generation temperature is 100 ° C. of the heater element 61, reads the radiation coefficient M _I of 0.99 ° C., and 200 ° C. flammable gas in the case of. In step S204, the calorific value calculation module 305, the independent variable of the radiation coefficients M _I of the calorific value calculation formula by substituting the values for the radiation coefficients M _I of the combustible gas, calculates the calorific values Q of the combustible gas To do. Thereafter, the calorific value calculation module 305 outputs the calculated calorific value Q to the output device 313 and stores it in the calorific value storage device 403.

As described above, without using an expensive gas chromatography device, from the measured values for the radiation coefficients M _I of the combustible gas, the value of the calorific value Q of the mixed gas of the combustible gas can be measured.

[Example of calorific value calculation]
Next, an example of the calorific value calculation method used by the gas control system according to the first embodiment of the present invention will be described. First, as shown in FIG. 11, 28 kinds of sample mixed gases with known calorific value Q were prepared. Each of the 28 kinds of sample mixed gases includes methane (CH ₄ ), ethane (C ₂ H ₆ ), propane (C ₃ H ₈ ), butane (C ₄ H ₁₀ ), nitrogen (N ₂ ), and It contained any or all of carbon dioxide (CO ₂ ). For example, no. The sample gas mixture of 7 contained 90 vol% methane, 3 vol% ethane, 1 vol% propane, 1 vol% butane, 4 vol% nitrogen, and 1 vol% carbon dioxide. No. The sample mixed gas of 8 contained 85 vol% methane, 10 vol% ethane, 3 vol% propane, and 2 vol% butane, and did not contain nitrogen and carbon dioxide. No. Nine sample gas mixtures contained 85 vol% methane, 8 vol% ethane, 2 vol% propane, 1 vol% butane, 2 vol% nitrogen, and 2 vol% carbon dioxide.

Then, the value of each of the radiation coefficient M _I of the 28 kinds of sample mixed gas, 100 ° C. The heating temperature of the heater element was measured by setting the 0.99 ° C., and 200 ° C.. For example, No. The sample mixed gas of No. 7 contains six kinds of gas components. As described above, ethane (C ₂ H ₆ ) and butane (C ₄ H ₁₀ ) are methane (CH ₄ ) and propane (C ₃ H). because be regarded as a mixture of _8), it is safe to measure the value of the three heating temperature of the radiation coefficient M _I. Then, the calorific values Q of 28 kinds of sample mixed gas, based on the value of the measured radiation coefficients M _I, by support vector regression, the radiation coefficient M _I as independent variables, the dependent variable calorific value Q A linear equation, a quadratic equation, and a cubic equation for calculating the calorific value Q were prepared.

When creating a linear equation for calculating the calorific value Q, the number of calibration points can be determined as appropriate using 3 to 5 calibration points. The created linear equation was given by the following equation (23). The calorific value Q of 28 kinds of sample mixed gas was calculated by the equation (23), and compared with the true calorific value Q, the maximum error was 2.1%.
Q = 39.91-20.59 × M _I (100 ° C)-0.89 × M _I (150 ° C) + 19.73 × M _I (200 ° C) ・ ・ ・ (23)

  When creating a quadratic equation for calculating the calorific value Q, the calibration points can be determined as appropriate using 8 to 9 calibration points. The calorific value Q of 28 kinds of sample mixed gas was calculated by the prepared quadratic equation and compared with the true calorific value Q. The maximum error was 1.2 to 1.4%.

  When creating a cubic equation for calculating the calorific value Q, 10 to 14 calibration points can be determined as appropriate. When the calorific value Q of 28 kinds of sample mixed gas was calculated by the created cubic equation and compared with the true calorific value Q, the maximum error was less than 1.2%. As shown in FIG. 12 and FIG. 13, the calorific value Q calculated by the cubic equation created by taking 10 calibration points is a good approximation to the true calorific value Q, with little error. there were.

[Gas control system]
Here, the gas control system according to the first embodiment of the present invention will be described. As shown in FIG. 14, the gas control system includes a crater portion 110 that ejects a mixed gas, which is a mixture of oxygen and air, which are flammable gases, and flammable gas, and flammable gas to the crater portion 110 side. A flammable gas piping system 120 for supplying gas to the crater 110, a flammable gas piping system 130 for supplying flammable gas to the crater 110, and a mixed gas piping system 140 for supplying mixed gas to the crater 110.

  The combustion-supporting gas piping system 120 includes a combustion-supporting gas flow path 121 for supplying the combustion-supporting gas to the crater portion 110 side. The combustion-supporting gas channel 121 includes an oxygen channel 121a for supplying oxygen and an air channel 121b for supplying air.

  The oxygen flow path 121a is provided with a regulator 122a, a flow controller 123a, a shut-off valve 124a, and a check valve 125a. The flow controller 123a includes an oxygen flow meter that detects the flow rate of oxygen flowing through the oxygen flow path 121a, and an oxygen control valve that controls the flow rate of oxygen flowing through the oxygen flow path 121a to be a target flow rate.

  A regulator 122b, a flow controller 123b, a shut-off valve 124b, and a check valve 125b are provided in the air flow path 121b. The flow controller 123b includes an air flow meter that detects the flow rate of air flowing through the air flow path 121b, and an air control valve that controls the flow rate of air flowing through the air flow path 121b to be a target flow rate.

  A mixer 126 that mixes the oxygen supplied from the oxygen flow path 121a and the air supplied from the air flow path 121b is provided at the junction of the oxygen flow path 121a and the air flow path 121b.

  The combustible gas piping system 130 includes a combustible gas passage 131 for supplying a combustible gas to the crater portion 110 side. The combustible gas flow path 131 is provided with a regulator 132, a flow controller 133, a shut-off valve 134, and a check valve 135. The flow controller 133 controls the combustible gas flowmeter for detecting the flow rate of the combustible gas flowing through the combustible gas flow path 131 and the flow rate of the combustible gas flowing through the combustible gas flow path 131 to the target flow rate. A combustible gas control valve. The combustible gas passage 131 is further provided with a calorific value calculation system 21A shown in FIG. The calorific value calculation system 21A calculates the calorific value of the combustible gas flowing through the combustible gas passage 131.

  14 is supplied from the flammable gas flow path 131 and the flammable gas flow path 131 to the junction of the flammable gas piping system 120 and the flammable gas piping system 130. A mixer 142 for mixing the combustible gas is provided. The mixed gas piping system 140 includes a mixer 142 and a mixed gas passage 141 for supplying the mixed gas supplied from the mixer 142 to the crater portion 110.

  A control device 150 is connected to the flow controllers 123a, 123b, 133 and the calorific value calculation system 21A. For example, the control device 150 stores a table indicating the relationship between the calorific value of the combustible gas and the optimum flow rate of the combustible gas corresponding to the calorific value of the combustible gas. Based on the calorific value of the combustible gas calculated by the calorific value calculation system 21A and the table, the control device 150 uses at least one of the flow controllers 123a, 123b, 133, and the flow rate of the combustible gas. The flow rate of the combustion-supporting gas is controlled. Thereby, in the mixer 142, combustible gas and combustion support gas are mixed by the flow rate ratio or volume ratio suitable for combustion.

Natural gas has a different component ratio of hydrocarbons depending on the gas field. Natural gas includes nitrogen (N ₂ ) and carbon dioxide (CO ₂ ), which are non-caloric components, in addition to hydrocarbons. Therefore, the volume ratio of the gas component contained in the natural gas differs depending on the output gas field, and the calorific value Q of the natural gas is often unknown even if the type of the gas component is known. Moreover, even if it is the natural gas derived from the same gas field, the calorific value Q is not always constant and may change depending on the sampling time.

On the other hand, according to the gas control system according to the first embodiment, it is possible to easily and accurately detect the accurate calorific value Q of the combustible gas such as natural gas. Therefore, it is possible to appropriately set the flow rate of the combustion-supporting gas necessary for burning the combustible gas. Therefore, it is possible to reduce the amount of wasteful carbon dioxide (CO ₂ ) emissions.

  The gas control system according to the first embodiment further includes an oxygen concentration sensor that detects the oxygen concentration of the combustion gas when the mixed gas of the combustible gas and the combustion-supporting gas is burned in the crater portion 110. It may be. In this case, the control device 150 uses at least one of the flow controllers 123a, 123b, and 133 to set the flow rate of the combustible gas and the flow rate of the combustion-supporting gas so that the oxygen concentration of the combustion gas is minimized. Control. In addition, when the oxygen concentration of the combustion gas exceeds the threshold value, the control device 150 may issue a warning that an abnormality has occurred in the gas control system.

(Modification of the first embodiment)
In the above formulas (12) to (15), the volume ratio V _A of the gas A of the mixed gas, the volume ratio V _{B of} the gas _B , the volume ratio V _{C of} the gas _C , and the volume ratio V _D of the gas _D are respectively It was shown that it is given as a function of the heat release coefficient M _I (T _H1 ), M _I (T _H2 ), M _I (T _H3 ) of the mixed gas. Here, according to Boyle Charles' law, the volume of the gas is proportional to the temperature of the gas itself. Therefore, for example, if the temperature of the mixed gas before the heat generating element 61 generates heat is T _I , the volume ratio V _{A of} the gas _A , the volume ratio V _{B of} the gas _B , the volume ratio V _{C of} the gas _C , and the gas D Each of the volume ratios V _D is represented by the following equations (24) to (27), and the heat dissipation coefficients M _I (T _H1 ), M _I (T _H2 ), M _I (T _H3 ) of the mixed gas and the mixed gas Is also given as a function of the temperature T _I of
V _A = f ₁ [M _I (T _H1 ), M _I (T _H2 ), M _I (T _H3 ), T _I ] (24)
V _B = f ₂ [M _I (T _H1 ), M _I (T _H2 ), M _I (T _H3 ), T _I ] (25)
V _C = f ₃ [M _I (T _H1 ), M _I (T _H2 ), M _I (T _H3 ), T _I ] (26)
V _D = f ₄ [M _I (T _H1 ), M _I (T _H2 ), M _I (T _H3 ), T _I ] (27)

Here, the following equation (28) is obtained by substituting the equations (24) to (27) into the above equation (6).
Q = K _A × V _A + K _B × V _B + K _C × V _C + K _D × V _D
= K _A × f ₁ [M _I (T _H1 ), M _I (T _H2 ), M _I (T _H3 ), T _I ]
+ K _B × f ₂ [M _I (T _H1 ), M _I (T _H2 ), M _I (T _H3 ), T _I ]
+ K _C × f ₃ [M _I (T _H1 ), M _I (T _H2 ), M _I (T _H3 ), T _I ]
+ K _D × f ₄ [M _I (T _H1 ), M _I (T _H2 ), M _I (T _H3 ), T _I ] (28)

As is apparent from the above equation (28), the calorific value Q per unit volume of the mixed gas is the heat dissipation coefficient M _I (M ₁₎ of the mixed gas when the heating temperature of the heating element 61 is T _H1 , T _H2 , T _H3. It is also given by an equation having variables T _H1 ), M _I (T _H2 ), M _I (T _H3 ) and the temperature T _{I of the} mixed gas. Therefore, the calorific value Q of the mixed gas can be given by the following equation (29), where g is a symbol representing a function.
Q = g [M _I (T _H1 ), M _I (T _H2 ), M _I (T _H3 ), T _I ] (29)

Therefore, when the heat generation temperature of the heat generating element 61 is T _H1 , T _H2 , T _H3 , the heat release coefficient M _I (T _H1 ), M _I (T _H2 ), M _I (T _H3 ) of the combustible gas, for example, The calorific value Q of the combustible gas can also be uniquely obtained by measuring the temperature T _I of the combustible gas before the heat generating element 61 generates heat and substituting it into the equation (29). Further, by adding the temperature T _I of the mixed gas to the calorific value calculation formula of the independent variable, the calculation accuracy of the calorific value Q of the mixed gas is further improved.

(Second Embodiment)
[Heat generation calculation formula creation system and calorific value calculation formula creation method]
First, a calorific value calculation formula creation system and a calorific value calculation formula creation method capable of creating a calorific value calculation formula used by the gas control system according to the second embodiment of the present invention will be described. Here, from the above equation (1), the temperature T _H of the heater element 61 shown in Figures 1 and 2 is given by the following equation (30).
_{T H = (1 / 2β)} × [-α + [α 2 - 4β (1 - R H / R H_STD)] 1/2] + T H_STD ... (30)
Therefore, the difference ΔT _H between the temperature T _H of the heating element 61 and the temperature T _{I of the} atmospheric gas is given by the following equation (31).
_{ΔT H = (1 / 2β)} × [-α + [α 2 - 4β (1 - R H / R H_STD)] 1/2] + T H_STD - T I ··· (31)

The temperature T _{I of the} atmospheric gas approximates the temperature T _I of the first temperature measuring element 62 to which power that does not generate heat is given. The relationship between the temperature T _I of the first temperature measuring element 62 and the resistance value R _I of the first temperature measuring element 62 is given by the following equation (32).
R _I = R _{I_STD} × [1 + α (T _I -T _{I_STD} ) + β (T _I -T _{I_STD} ) ² ] (32)
T _{I_STD} represents the standard temperature of the first temperature measuring element 62 and is, for example, 20 ° C. R _{I_STD} represents the resistance value of the first temperature measuring element 62 measured in advance at the standard temperature T _{I_STD} . From the above equation (32), the temperature T _I of the first temperature measuring element 62 is given by the following equation (33).
_{T I = (1 / 2β)} × [-α + [α 2 - 4β I (1 - R I / R I_STD)] 1/2] + T I_STD ... (33)

Therefore, the radiation coefficient M _I of the atmospheric gas is also given by the following equation (34).
M _I = P _H / ΔT _H
= P _H / [(1 / 2β) [-α + [α ² -4β (1-R _H / R _{H_STD} )] ^1/2 ] + T _{H_STD-} (1 / 2β) [-α + [α ^2- 4β (1-R _I / R _{I_STD} )] ^1/2 ] -T _{I_STD} ] ... (34)
Since the energizing current I _H and the driving power P _H or voltage V _H of the heating element 61 can be measured, the resistance value R _H of the heating element 61 can be calculated from the above equation (2) or (3). Similarly, the resistance value R _{I of} the first temperature measuring element 62 can also be calculated.

As shown in the above equation (17), the calorific value Q per unit volume of the mixed gas composed of four kinds of gas components is the mixture when the heating temperature of the heating element 61 is T _H1 , T _H2 , T _H3. It is given by an equation with the gas heat dissipation coefficients M _I (T _H1 ), M _I (T _H2 ), and M _I (T _H3 ) as variables. Moreover, the radiation coefficient M _I of the mixed gas, as shown in above (34), depends on the resistance value R _H of the heater element 61, the resistance value R _I of the first temperature measurement element 62, the. Therefore, the present inventors have determined that the calorific value Q per unit volume of the mixed gas is the heating element when the temperature of the heating element 61 is T _H1 , T _H2 , T _H3 as shown in the following equation (35). An equation using the resistance value R _H1 (T _H1 ), R _H2 (T _H2 ), R _H3 (T _H3 ) of 61 and the resistance value R _{I of} the first temperature measuring element 62 in contact with the mixed gas as variables I also found that it was given.
Q = g [R _H1 (T _H1 ), R _H2 (T _H2 ), R _H3 (T _H3 ), R _I ] (35)

Therefore, the resistance values R _H1 (T _H1 ), R _H2 (T _H2 ), R _H3 (T _H of the heating element 61 when the heating temperature of the heating element 61 in contact with the combustible gas is T _H1 , T _H2 , T _H3. and _H3), for example, the resistance value R _I of the first temperature measurement element 62 that comes into contact with the combustible gas before the heater element 61 generates heat is measured, by substituting the equation (35), heating of the combustible gas The quantity Q can be determined uniquely.

Further, the calorific value Q per unit volume of the mixed gas is, as shown in the following formula (36), the energization current I _H1 of the heating element 61 when the temperature of the heating element 61 is T _H1 , T _H2 , T _H3. (T _H1 ), I _H2 (T _H2 ), I _H3 (T _H3 ) and an energization current I _{I of} the first temperature measuring element 62 in contact with the mixed gas are also given by equations.
Q = g [I _H1 (T _H1 ), I _H2 (T _H2 ), I _H3 (T _H3 ), I _I ] (36)

Alternatively, the calorific value Q per unit volume of the mixed gas is the voltage V _H1 (V _H1 applied to the heating element 61 when the temperature of the heating element 61 is T _H1 , T _H2 , T _H3 , as shown in the following equation (37). T _H1 ), V _H2 (T _H2 ), V _H3 (T _H3 ), and the voltage V _I applied to the first temperature measuring element 62 in contact with the mixed gas are also given as equations.
Q = g [V _H1 (T _H1 ), V _H2 (T _H2 ), V _H3 (T _H3 ), V _I ] (37)

Alternatively, the calorific value Q per unit volume of the mixed gas is an analog connected to the heating element 61 when the temperature of the heating element 61 is T _H1 , T _H2 , T _H3 , as shown in the following equation (38). _-The output signal AD _H1 (T _H1 ), AD _H2 (T _H2 ), AD _H3 (T _H3 ) of the digital conversion circuit (hereinafter referred to as “A / D conversion circuit”) and the first measurement in contact with the mixed gas. An equation having the output signal AD _{I of} the A / D conversion circuit connected to the temperature element 62 as a variable is also given.
Q = g [AD _H1 (T _H1 ), AD _H2 (T _H2 ), AD _H3 (T _H3 ), AD _I ] (38)

Therefore, the calorific value Q per unit volume of the mixed gas is an electric signal from the heating element 61 when the heating temperature of the heating element 61 is T _H1 , T _H2 , T _H3 as shown in the following equation (39). S _H1 (T _H1 ), S _H2 (T _H2 ), S _H3 (T _H3 ), and the electric signal S _I from the first temperature measuring element 62 in contact with the mixed gas are given by equations having variables.
Q = g [S _H1 (T _H1 ), S _H2 (T _H2 ), S _H3 (T _H3 ), S _I ] (39)

Here, the calorific value calculation formula creation system 20B shown in FIG. 15 has an electrical signal S _I from the first temperature measuring element 62 shown in FIGS. 1 and 2 that depends on the temperature T _I of each of the plurality of sample mixed gases. value and the value of the electric signal S _H from the heater element 61 at each of the plurality of heat producing temperatures T _H, the measurement module 321 shown in FIG. 15 for measuring the, the known calorific value Q of the plurality of sample mixed gases The electric signal S _I from the first temperature measuring element 62 based on the value, the value of the electric signal S _I from the first temperature measuring element 62, and the value of the electric signal from the heating element 61 at a plurality of heating temperatures. and a electric signal S _H as independent variables from the heater element 61 at a plurality of heat producing temperatures T _H, the formula creation module that creates a calorific value calculation formula to the calorific value Q as a dependent variable, a.

After the chamber 101 is filled with the first sample mixed gas, the first temperature measuring element 62 of the microchip 8 shown in FIGS. 1 and 2 receives the electric signal S _I depending on the temperature of the first sample mixed gas. Is output. Next, the heater element 61 applies driving powers P _H1, P _H2, P _H3 from the driving circuit 303 shown in FIG. 15. When the driving powers P _H1 , P _H2 , and P _H3 are given, the heating element 61 in contact with the first sample mixed gas has, for example, a temperature T _{H1 of} 100 ° C., a temperature T _{H2 of} 150 ° C., and a temperature of 200 ° C. generates heat T _H3, the electric signal S _H1 at the heat producing temperature T _H1 (T _H1), an electric signal S _H2 at the heat producing temperature T _H2 (T _H2), and the electric signal S _H3 at the heat producing temperature T _H3 of (T _H3) output To do.

After the first sample mixed gas is removed from the chamber 101, the chamber 101 is sequentially filled with the second to fourth sample mixed gases. After the second sample mixed gas is filled in the chamber 101, the first temperature measuring element 62 of the microchip 8 shown in FIG. 1 and FIG. 2 receives the electric signal S _I depending on the temperature of the second sample mixed gas. Is output. Next, the heater element 61 that comes into contact with the second sample mixed gas, heating temperature T the electrical signal at _H1 S _H1 (T _H1), an electric signal S _H2 (T _H2) at the heat producing temperature T _H2, and the heat producing temperature T _H3 The electric signal S _H3 (T _H3 ) is output.

After the third sample mixed gas is filled in the chamber 101 shown in FIG. 15, the first temperature measuring element 62 of the microchip 8 shown in FIGS. 1 and 2 depends on the temperature of the third sample mixed gas. The electric signal S _I is output. Next, the heater element 61 that comes into contact with the third sample mixed gas, heating temperature T the electrical signal at _H1 S _H1 (T _H1), an electric signal S _H2 (T _H2) at the heat producing temperature T _H2, and the heat producing temperature T _H3 The electric signal S _H3 (T _H3 ) is output.

After the fourth sample mixed gas is filled in the chamber 101 shown in FIG. 15, the first temperature measuring element 62 of the microchip 8 shown in FIGS. 1 and 2 depends on the temperature of the fourth sample mixed gas. The electric signal S _I is output. Next, the heater element 61 that comes into contact with the fourth sample mixed gas, heating temperature T the electrical signal at _H1 S _H1 (T _H1), an electric signal S _H2 (T _H2) at the heat producing temperature T _H2, and the heat producing temperature T _H3 The electric signal S _H3 (T _H3 ) is output.

In addition, when each sample mixed gas contains n types of gas components, the heating element 61 shown in FIGS. 1 and 2 of the microchip 8 is caused to generate heat at at least n−1 types of different temperatures. However, as described above, methane (CH ₄₎ and propane (C ₃ H ₈₎ other than the alkane (C _j H _{2j + 2)} is regarded as a mixture of methane (CH ₄₎ and propane (C ₃ H ₈₎ sell. Accordingly, a sample mixed gas composed of n kinds of gas components, where z is a natural number, is added to methane (CH ₄ ) and propane (C ₃ H ₈ ) as gas components, and z kinds of alkanes (C _j H _{2j + 2} ). In the case where the heat generating element 61 is included, the heat generating element 61 generates heat at at least nz-1 different temperatures.

As shown in FIG. 15, the microchip 8 is connected to a central processing unit (CPU) 300 that includes a measurement module 321. An electrical signal storage device 421 is connected to the CPU 300. Measurement module 321, the value of the electric signal S _I from the first temperature measuring element 62, the electric signal S _H1 (T _H1) at a heat producing temperature T _H1, from the heater element 61, the electric signal S _H2 at the heat producing temperature T _H2, (T _H2 ) and the value of the electric signal S _H3 (T _H3 ) at the heat generation temperature T _H3 are measured, and the measured value is stored in the electric signal storage device 421.

The electric signal S _I from the first temperature measuring element 62 includes the resistance value R _I of the first temperature measuring element 62, the conduction current I _I of the first temperature measuring element 62, and the first temperature measuring element. Either the voltage V _I applied to 62 or the output signal AD _I of the A / D conversion circuit 304 connected to the first temperature measuring element 62 may be used. Similarly, the electric signal S _H from the heater element 61, the resistance value R _H of the heater element 61, current I _H flowing in the heater element 61, which is connected to the voltage V _H and the heating element 61, according to the heating elements 61 it may be any of the output signal AD _H of the a / D conversion circuit 304.

Formula creation module 302 included in the CPU300, for example each of the known calorific value Q of the first to fourth sample mixed gases, the plurality of measured values of electric signals S _I from the first temperature measurement element 62 And a plurality of measured values of the electrical signals S _H1 (T _H1 ), S _H2 (T _H2 ), and S _H3 (T _H3 ) from the heating element 61 are collected. Formula creation module 302 further collected calorific value Q, based on the values of the electric signals S _I, and the electric signals S _H, by multivariate analysis, the electric signal S _I and the heating element from the first temperature measuring element 62 A calorific value calculation formula is calculated with the electric signals S _H1 (T _H1 ), S _H2 (T _H2 ) and S _H3 (T _H3 ) from 61 as independent variables and the calorific value Q as a dependent variable. The other components of the calorific value calculation formula creation system 20B shown in FIG. 15 are the same as those of the calorific value calculation formula creation system 20A shown in FIG.

[Heat generation calculation system]
Next, a calorific value calculation system provided in the gas control system according to the second embodiment of the present invention will be described. As shown in FIG. 16, the calorific value calculation system 21B has a value of the electric signal S _I from the first temperature measuring element 62 that depends on the temperature T _I of the combustible gas and each of the plurality of exothermic temperatures T _H. and values of the electric signals S _H from the heater element 61, a measurement module 321 that measures the electrical signal S from the heating element 61 in the electric signal S _I and the plurality of heat producing temperatures T _H from the first temperature measuring element 62 the _H as independent variables, the formula storage device 402 that stores the calorific value calculation formula to the calorific value Q as a dependent variable, independent variable of the electric signal S _I from the first temperature measuring element 62 of the calorific value calculation formula and, the independent variables of the electric signal S _H from the heater element 61, substituting the measured value of the electric signal S _I from the first temperature measurement element 62, and the measured values of the electric signals S _H from the heater element 61, combustible A calorific value calculation module for calculating a calorific value Q of the gas; Is provided.

Calorific value calculation formula, for example, the electric signal S _I from the first temperature measuring element 62, and the electric signal S _H1 (T _H1) from the heating temperature T _H1 is the heater element 61 of 100 ° C., heating producing temperature T _{H2, Includes} an electric signal S _H2 (T _H2 ) from the heating element 61 having a heating temperature of 150 ° C. and an electric signal S _H3 (T _H3 ) from the heating element 61 having a heating temperature T _H3 of 200 ° C. as independent variables.

The first temperature measurement element 62 of the microchip 8 shown in Figs. 1 and 2 outputs an electric signal S _I that is dependent on the temperature of the combustible gas. Next, the heater element 61 applies driving powers P _H1, P _H2, P _H3 from the driving circuit 303 shown in FIG. 15. When the driving powers P _H1 , P _H2 , and P _H3 are given, the heating element 61 in contact with the combustible gas has a temperature T _{H1 of} 100 ° C., a temperature T _{H2 of} 150 ° C., and a temperature T _H3 of 200 ° C., for example. fever, electric signals S _H1 at the heat producing temperature T _H1 (T _H1), an electric signal S _H2 (T _H2) at the heat producing temperature T _H2, and an electric signal S _H3 (T _H3) at the heat producing temperature T _H3.

Measurement module shown in FIG. 16 321, the value of the electric signal S _I from the first temperature measurement element 62 coming into contact with combustible gas, the electrical signal at a heat producing temperature T _H1, from the heater element 61 coming into contact with flammable gases S _H1 (T _H1), an electric signal S _H2 at the heat producing temperature T _H2 (T _H2), and the value of the electric signal S _H3 (T _H3) at the heat producing temperature T _H3, were measured, the measured value into an electric signal storage device 421 save.

Calorific value calculation module 305, an electric signal S _H1 (T _H1 from independent variables and the heater element 61 of the electric signal S _I from the first temperature measuring element 62 of the calorific value calculation formula stored in the formula storage device 402 ), S _H2 (T _H2 ), S _H3 (T _H3 ), the measured values are substituted into the independent variables, and the calorific value Q of the combustible gas is calculated. The other components of the calorific value calculation system 21B shown in FIG. 16 are the same as those of the calorific value calculation system 21A shown in FIG.

[Gas control system]
As shown in FIG. 17, in the gas control system according to the second embodiment, the calorific value calculation system 21 </ b> B described above is arranged in the combustible gas channel 131. Since the other components of the gas control system according to the second embodiment are the same as those of the first embodiment, description thereof is omitted. According to the gas control system according to the second embodiment, since the calculation of the heat dissipation coefficient can be omitted, the calorific value Q of the combustible gas can be calculated at a higher speed.

(Other embodiments)
As described above, the present invention has been described according to the embodiment. However, it should not be understood that the description and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, embodiments, and operation techniques should be apparent to those skilled in the art. For example, FIG. 18 shows the relationship between the heat dissipation coefficient of the mixed gas and the thermal conductivity when currents of 2 mA, 2.5 mA, and 3 mA are passed through the heating resistor. As shown in FIG. 18, the heat dissipation coefficient of the mixed gas and the thermal conductivity are generally in a proportional relationship. Therefore, in the above-described example, when the calorific value calculation formula is created, the value of the heat dissipation coefficient of the mixed gas at a plurality of heating temperatures of the heating resistor is used. The value of the thermal conductivity of the mixed gas may be used. Thus, it should be understood that the present invention includes various embodiments and the like not described herein.

8 Microchip 10 Measurement mechanism 18 Heat insulation member 20A, 20B Heat generation amount calculation formula creation system 21A, 21B Heat generation amount calculation system 31A, 31B, 31C, 31D Gas pressure regulators 32A, 32B, 32C, 32D Flow control devices 50A, 50B, 50C, 50D Gas cylinder 60 Substrate 61 Heating element 62 First temperature measuring element 63 Second temperature measuring element 64 Thermal insulation element 65 Insulating film 66 Cavity 91A, 91B, 91C, 91D, 92A, 92B, 92C, 92D, 93, 102 , 103 channel 101 chamber 110 crater part 120 combustion-supporting gas piping system 121 combustion-supporting gas channel 121a oxygen channel 121b air channel 122a, 122b regulators 123a, 123b, 133 flow controllers 124a, 124b shut-off valves 125a, 125b Check valve 126 Mixer 130 Combustible gas piping system 131 Combustible gas flow path 132 Regulator 134 Shut-off valve 135 Check valve 140 Mixed gas piping system 141 Mixed gas flow path 142 Mixer 150 Controller 161, 162, 163, 164, 165, 181, 182, 183 Resistance elements 170 and 171 Operational amplifier 301 Heat dissipation coefficient calculation module 302 Formula creation module 303 Drive circuit 304 A / D conversion circuit 305 Heat generation amount calculation module 312 Input device 313 Output device 321 Measurement module 401 Heat dissipation coefficient storage device 402 Formula storage device 403 Heat generation Quantity storage device 421 Electric signal storage device

Claims (32)

A measurement mechanism that measures the value of the heat release coefficient or thermal conductivity of the combustible gas when the heating element generates heat at a plurality of heat generation temperatures;
A formula storage device for storing a calorific value calculation formula having the heat dissipation coefficient or thermal conductivity for the plurality of heat generation temperatures as an independent variable and a calorific value as a dependent variable;
Substituting the value of the heat release coefficient or thermal conductivity of the combustible gas for the plurality of heat generation temperatures into the independent variable of the heat release coefficient or heat conductivity for the plurality of heat generation temperatures in the calorific value calculation formula, A calorific value calculation unit for calculating a calorific value of the property gas;
Based on the calculated value of the calorific value of the combustible gas, a control device that controls the mixing of the combustible gas and the combustion-supporting gas;
A gas control system. A combustible gas flow meter for detecting the flow rate of the combustible gas;
A combustion-supporting gas flow meter for detecting a flow rate of the combustion-supporting gas;
The gas control system according to claim 1, further comprising:   The gas control system according to claim 2, further comprising a combustion support gas control valve that controls a flow rate of the combustion support gas based on a calculated value of a calorific value of the combustible gas.   The gas control system according to claim 2 or 3, further comprising a combustible gas control valve that controls a flow rate of the combustible gas based on a calculated value of the calorific value of the combustible gas.   The gas control system according to any one of claims 1 to 4, further comprising an oxygen concentration sensor that detects an oxygen concentration of the combustion gas when the mixed gas of the combustible gas and the combustion-supporting gas is burned. .   6. The gas control system according to claim 1, wherein the number of the plurality of temperatures is at least a number obtained by subtracting 1 from the number of a plurality of types of gas components contained in the combustible gas.   The gas control system according to any one of claims 1 to 6, wherein the combustible gas is natural gas.   The gas control system according to any one of claims 1 to 7, wherein the combustible gas includes methane, propane, nitrogen, and carbon dioxide. Measuring the value of the heat release coefficient or thermal conductivity of the combustible gas when the heating element generates heat at a plurality of heat generation temperatures;
Preparing a calorific value calculation formula with the heat dissipation coefficient or thermal conductivity for the plurality of heat generation temperatures as an independent variable, and a calorific value as a dependent variable;
Substituting the value of the heat release coefficient or thermal conductivity of the combustible gas for the plurality of heat generation temperatures into the independent variable of the heat release coefficient or heat conductivity for the plurality of heat generation temperatures in the calorific value calculation formula, Calculating the value of the calorific value of the property gas,
Based on the calculated value of the calorific value of the combustible gas, controlling the mixing of the combustible gas and the combustion-supporting gas;
Including a gas control method. Detecting the flow rate of the combustible gas;
Detecting the flow rate of the combustion-supporting gas;
The gas control method according to claim 9, further comprising:   The gas control method according to claim 10, further comprising controlling a flow rate of the combustion-supporting gas based on a calculated value of a calorific value of the combustible gas.   The gas control method according to claim 10 or 11, further comprising controlling a flow rate of the combustible gas based on a calculated value of a calorific value of the combustible gas.   The gas control method according to any one of claims 9 to 12, further comprising detecting an oxygen concentration of the combustion gas when the mixed gas of the combustible gas and the combustion-supporting gas is combusted.   14. The gas control method according to claim 9, wherein the number of the plurality of temperatures is at least one obtained by subtracting 1 from the number of the plurality of types of gas components contained in the combustible gas.   The gas control method according to any one of claims 9 to 14, wherein the combustible gas is natural gas.   The gas control method according to claim 9, wherein the combustible gas includes methane, propane, nitrogen, and carbon dioxide. A flow path through which a combustible gas flows;
A temperature measuring element disposed in the flow path;
A heating element that is disposed in the flow path and generates heat at a plurality of heating temperatures;
A measurement module that measures the value of the electrical signal from the temperature measuring element depending on the temperature of the combustible gas, and the value of the electrical signal from the heating element at each of the plurality of heating temperatures;
An equation storage device for storing a calorific value calculation formula having an electrical signal from the temperature measuring element and an electrical signal from the heating element at the plurality of heating temperatures as independent variables, and a calorific value as a dependent variable;
In the independent variable of the electrical signal from the temperature measuring element and the independent variable of the electrical signal from the heating element of the calorific value calculation formula, the value of the electrical signal from the temperature measuring element, and the electricity from the heating element Substituting the value of the signal, a calorific value calculation unit for calculating the calorific value of the combustible gas,
Based on the calculated value of the calorific value of the combustible gas, a control device that controls the mixing of the combustible gas and the combustion-supporting gas;
A gas control system. A combustible gas flow meter for detecting the flow rate of the combustible gas;
A combustion-supporting gas flow meter for detecting a flow rate of the combustion-supporting gas;
The gas control system according to claim 17, further comprising:   The gas control system according to claim 18, further comprising a combustion support gas control valve that controls a flow rate of the combustion support gas based on a calculated value of a calorific value of the combustible gas.   The gas control system according to claim 18 or 19, further comprising a combustible gas control valve that controls a flow rate of the combustible gas based on a calculated value of a calorific value of the combustible gas.   The gas control system according to any one of claims 17 to 20, further comprising an oxygen concentration sensor that detects an oxygen concentration of the combustion gas when the mixed gas of the combustible gas and the combustion-supporting gas is combusted. .   The gas control system according to any one of claims 17 to 21, wherein the number of the plurality of temperatures is at least one obtained by subtracting 1 from the number of the plurality of types of gas components contained in the combustible gas.   The gas control system according to any one of claims 17 to 22, wherein the combustible gas is natural gas.   The gas control system according to any one of claims 17 to 23, wherein the combustible gas includes methane, propane, nitrogen, and carbon dioxide. Obtaining the value of the electrical signal from the temperature measuring element depending on the temperature of the combustible gas;
Heating the heating element in contact with the combustible gas at a plurality of heating temperatures;
Obtaining a value of an electrical signal from the heating element at each of the plurality of heating temperatures;
Preparing a calorific value calculation formula with the electrical signal from the temperature measuring element and the electrical signal from the heating element at the plurality of heat generation temperatures as independent variables, and the calorific value as a dependent variable;
In the independent variable of the electrical signal from the temperature measuring element and the independent variable of the electrical signal from the heating element in the calorific value calculation formula, the value of the electrical signal from the temperature measuring element and the electrical signal from the heating element Substituting the value of, and calculating the calorific value of the combustible gas;
Based on the calculated value of the calorific value of the combustible gas, controlling the mixing of the combustible gas and the combustion-supporting gas;
Including a gas control method. Detecting the flow rate of the combustible gas;
Detecting the flow rate of the combustion-supporting gas;
The gas control method according to claim 25, further comprising:   27. The gas control method according to claim 26, further comprising controlling a flow rate of the combustion-supporting gas based on a calculated value of the calorific value of the combustible gas.   The gas control method according to claim 26 or 27, further comprising controlling a flow rate of the combustible gas based on a calculated value of a calorific value of the combustible gas.   The gas control method according to any one of claims 25 to 28, further comprising detecting an oxygen concentration of the combustion gas when the mixed gas of the combustible gas and the combustion-supporting gas is combusted.   30. The gas control method according to claim 25, wherein the number of the plurality of temperatures is at least a number obtained by subtracting 1 from the number of the plurality of types of gas components contained in the combustible gas.   The gas control method according to any one of claims 25 to 30, wherein the combustible gas is natural gas.   The gas control method according to any one of claims 25 to 31, wherein the combustible gas includes methane, propane, nitrogen, and carbon dioxide.

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