JP5335728B2 - Calorific value calculation formula creation system, calorific value calculation formula creation method, calorific value measurement system, and calorific value measurement method - Google Patents

Description

  The present invention relates to a gas inspection technique, and relates to a calorific value calculation formula creation system, a calorific value calculation formula creation method, a calorific value measurement system, and a calorific value measurement method.

Conventionally, when determining the calorific value of a mixed gas, it is necessary to analyze the components of the mixed gas using an expensive gas chromatography apparatus or the like. Further, by measuring the thermal conductivity of the mixed gas and the speed of sound in the mixed gas, methane (CH ₄ ), propane (C ₃ H ₈ ), nitrogen (N ₂ ), and carbon dioxide (CO ₂ ) contained in the mixed gas. ) Has been proposed (see, for example, Patent Document 1).

JP-T-2004-514138

  However, the method disclosed in Patent Document 1 requires an expensive sound speed sensor for measuring sound speed in addition to the sensor for measuring thermal conductivity. Accordingly, an object of the present invention is to provide a calorific value calculation formula creation system, a calorific value calculation formula creation method, a calorific value measurement system, and a calorific value measurement method capable of easily measuring the calorific value of gas. I will.

  According to the aspect of the present invention, (a) a heating element that heats each of a plurality of mixed gases including a plurality of types of gas components, and (b) a gas temperature value of each of the plurality of mixed gases, and a heating element A measurement mechanism for measuring the values of the physical properties of the plurality of mixed gases when heat is generated at a plurality of heat generation temperatures; and (c) a known calorific value of each of the plurality of mixed gases and a value of the measured gas temperature. And a formula creation module that creates a calorific value calculation formula using the physical properties of the gas temperature and the plural exothermic temperatures as independent variables and the calorific value as a dependent variable based on the physical property values measured for the plural exothermic temperatures. A calorific value calculation formula creating system is provided. The physical property is, for example, a heat dissipation coefficient or thermal conductivity.

  According to another aspect of the present invention, (a) preparing a plurality of mixed gases containing a plurality of types of gas components, (b) measuring a value of each gas temperature of the plurality of mixed gases, (C) measuring values of physical properties of a plurality of mixed gases when the heating element is heated at a plurality of heat generation temperatures; and (d) measuring values of known calorific values of the plurality of mixed gases. Based on the measured gas temperature values and the physical property values measured for multiple exothermic temperatures, the calorific value calculation formula with the physical properties for the gas temperature and multiple exothermic temperatures as independent variables and the exothermic amount as a dependent variable A method for creating a calorific value calculation formula is provided.

  According to still another aspect of the present invention, (a) the gas temperature value of the measurement target mixed gas whose calorific value is unknown, and the physical property values of the measurement target mixed gas when the heating element generates heat at a plurality of heat generation temperatures. (B) a formula storage device that stores a calorific value calculation formula having physical properties for the gas temperature and a plurality of exothermic temperatures as independent variables and a calorific value as a dependent variable; and (c) a calorific value calculation formula. Substituting the gas temperature value of the measurement target mixed gas and the physical property value of the measurement target mixed gas with respect to multiple exothermic temperatures into the independent variable of the gas temperature and the physical property independent variable for multiple exothermic temperatures, A calorific value measurement system is provided, comprising a calorific value calculation module for calculating a calorific value. The physical property is, for example, a heat dissipation coefficient or thermal conductivity.

  According to still another aspect of the present invention, (a) the value of the gas temperature of the measurement target mixed gas whose calorific value is unknown, and the physical properties of the measurement target mixed gas when the heating element generates heat at a plurality of heat generation temperatures. Measuring a value; (b) preparing a calorific value calculation formula having the physical properties of the gas temperature and a plurality of exothermic temperatures as independent variables and a calorific value as a dependent variable; and (c) gas of the calorific value calculation formula. Substituting the value of the gas temperature of the gas mixture to be measured and the value of the gas property of the gas mixture to be measured for multiple heat generation temperatures into the temperature independent variable and the property independent variable for multiple heat generation temperatures, the calorific value of the gas mixture to be measured And a calorific value measurement method is provided.

  According to the present invention, it is possible to provide a calorific value calculation formula creation system, a calorific value calculation formula creation method, a calorific value measurement system, and a calorific value measurement method that can easily measure the calorific value of gas.

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. 1 is a first schematic diagram of a gas property value measurement system according to a first embodiment of the present invention. It is a 2nd schematic diagram of the gas physical property value measurement system which concerns on the 1st Embodiment of this 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 schematic diagram which shows the gas physical property value measurement 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. It is a schematic diagram which shows the gas physical property value measurement system which concerns on the 3rd Embodiment of this invention. It is a graph which shows the relationship between the density | concentration of the gas which concerns on the 3rd Embodiment of this invention, and a heat dissipation coefficient. It is a schematic diagram which shows the gas physical property value measurement system which concerns on the 4th Embodiment of this invention. It is a flowchart which shows the measuring method of the emitted-heat amount which concerns on the 4th Embodiment of this invention. It is a table | surface which shows the composition of the sample mixed gas and calorific value which concern on Example 1 of embodiment of this invention. It is a graph which shows the calorific value computed and the true calorific value of the sample mixed gas concerning Example 1 of an embodiment of the invention. It is a graph which shows the relationship between the true calorific value of the sample mixed gas which concerns on Example 1 of embodiment of this invention, and the calculated calorific value. It is a 1st graph which shows the difference | error from the true value of the calculated calorific value of the sample mixed gas which concerns on Example 2 of embodiment of this invention. It is a 2nd graph which shows the difference | error from the true value of the calculated calorific value of the sample mixed gas which concerns on Example 2 of embodiment of this invention. It is a 3rd graph which shows the error from the true value of the calorific value calculated of the sample mixed gas which concerns on Example 2 of embodiment of this invention.

  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)
First, the microchip 8 used in the gas property value measurement system according to the first embodiment will be described with reference to 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. Temperature measuring element 63 and a third temperature measuring element 64 provided on the substrate 60.

  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, the second temperature measuring element 63, and the third temperature measuring element 64 is a resistor, for example, and detects the gas temperature of the atmospheric gas before the heating element 61 generates heat. . Note that the gas temperature may be detected using only any one of the first temperature measuring element 62, the second temperature measuring element 63, and the third temperature measuring element 64. 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.

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. In addition, platinum (Pt) or the like can be used as a material for each of the heating element 61, the first temperature measuring element 62, the second temperature measuring element 63, and the third temperature measuring element 64. It can be formed.

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. In equilibrium, as shown in the following equation (4), the driving power P _H of the heater element 61 is divided by the difference between the temperature T _I of the heating temperature T _H and the ambient gas of the heater element 61, the atmospheric gas A heat dissipation coefficient M _I is obtained. The unit of the heat dissipation coefficient M _I is, for example, W / ° C.
M _I = P _H / (T _H -T _I ) (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 _{I 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 _I 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.

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)

Furthermore, according to Boyle's Law, the volume of the gas is proportional to the temperature of the gas itself. Here, for example, if the temperature of the mixed gas before the heating 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 of the mixed gas has a heat release coefficient M _I (T _H1 ), M _I (T _H2 ), M _I (T _H3 ) and a mixture as shown in the following equations (16) to (19). It is given as a function of the gas temperature T _I.
V _A = f ₁ [M _I (T _H1 ), M _I (T _H2 ), M _I (T _H3 ), T _I ] (16)
V _B = f ₂ [M _I (T _H1 ), M _I (T _H2 ), M _I (T _H3 ), T _I ] (17)
V _C = f ₃ [M _I (T _H1 ), M _I (T _H2 ), M _I (T _H3 ), T _I ] (18)
V _D = f ₄ [M _I (T _H1 ), M _I (T _H2 ), M _I (T _H3 ), T _I ] (19)

Here, the following equation (20) 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 ), 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 ] (20)

As is clear from the above equation (20), the calorific value Q per unit volume of the mixed gas is the heat release coefficient M _I (M ₁₎ of the mixed gas when the heat generation temperature of the heating element 61 is T _H1 , T _H2 , T _H3. T _H1 ), M _I (T _H2 ), M _I (T _H3 ) and the temperature of the mixed gas T _I are given by equations. Therefore, the calorific value Q of the mixed gas is given by the following equation (21), where g is a symbol representing a function.
Q = g [M _I (T _H1 ), M _I (T _H2 ), M _I (T _H3 ), T _I ] (21)

Therefore, if the above equation (21) is obtained in advance for the 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 the temperature T _I of the inspection target mixed gas and substituting it into the equation (21) makes it possible to uniquely determine the calorific value Q of the inspection target mixed gas.

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,. T _Hn-1 radiation coefficient of the mixed gas to _{M I (T H1), M} I (T H2), M I (T H3), ···, M I and (T _Hn-1), the temperature T of the mixed gas An equation having _I and _V as variables is acquired in advance. 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 Measure the heat dissipation coefficient M _I (T _H1 ), M _I (T _H2 ), M _I (T _H3 ), ..., M _I (T _Hn-1 ) and the temperature T _{I of the} gas mixture to be inspected. By substituting into the equation (22), the calorific value Q per unit volume of the mixed gas to be inspected can be uniquely obtained.
Q = g [M _I (T _H1 ), M _I (T _H2 ), M _I (T _H3 ), ..., M _I (T _Hn-1 ), T _I ] ... (22)

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 (22). 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 (23) to (26): The formula (22) 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 ... (23)
C ₄ H ₁₀ = -0.5 CH ₄ + 1.5 C ₃ H ₈ ... (24)
C ₅ H ₁₂ = -1.0 CH ₄ + 2.0 C ₃ H ₈ ... (25)
C ₆ H ₁₄ = -1.5 CH ₄ + 2.5 C ₃ H ₈ ... (26)

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 for the calculation of the equation (22) and the type of the gas component of the mixed gas to be inspected whose calorific value Q per unit volume is unknown are the same. Of course, the equation (22) 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 (22), Equation (22) can be used. For example, the mixed gas used in the calculation of the equation (22) has 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 (22) 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 (22) includes 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 (22). Even if the alkane (C _j H _{2j + 2} ) not contained in the mixed gas is contained, the formula (22) 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 (22) Formula.

Here, the gas property value measurement system 20 according to the first embodiment shown in FIG. 6 includes a chamber 101 filled with a sample mixed gas having a known calorific value Q, and the heat generation shown in FIGS. The element 61, the first temperature measuring element 62, and the second temperature measuring element 63 are used to measure the values of the plurality of heat dissipation coefficients M _I of the sample mixed gas and the temperature T _I of the sample mixed gas in FIG. Measuring mechanism 10 shown. Further, the gas property value measurement system is configured to generate a heating element based on a known calorific value Q of the sample mixed gas, a plurality of heat dissipation coefficients M _I of the sample mixed gas, and a temperature T _I of the sample mixed gas. An equation creation module 302 is provided that creates a calorific value calculation formula with the gas heat release coefficient M _I and the gas temperature T _I as independent variables and the gas calorific value Q 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 gas property value measurement system 20 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. The second flow rate controller 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 gas property value measurement system 20 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 gas property value measurement system 20 via the flow paths 92C, 93, 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 gas property value measurement system 20 via the flow paths 92D, 93, and 102.

Each of the first to fourth sample mixed gases is, for example, natural gas. 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.

Further, the measurement mechanism 10 shown in FIG. 6 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 gas property value measurement system 20 shown in FIG. 6 further includes a heat dissipation coefficient storage device 401 connected to the CPU 300. The heat dissipation coefficient calculation module 301 stores the measured gas temperature value T _I and the calculated heat dissipation coefficient M _{I in} the heat dissipation coefficient storage device 401.

For example, the formula creation module 302 has a known calorific value Q of each of the first to fourth sample mixed gases and a value of a heat dissipation coefficient M _I of a plurality of gases when the heat generation temperature of the heat generating element 61 is 100 ° C. when the radiation coefficient M _I of the plurality of the gas when the heat producing temperature of the heater element 61 is 0.99 ° C., the value of the radiation coefficient M _I of the plurality of the gas when the heat producing temperature of the heater element 61 is 200 ° C., Collect the values of the temperatures T _I of the gases. Further, the formula creation module 302 uses the multivariate analysis based on the collected heat generation amount Q, the plurality of heat dissipation coefficients M _I , and the values of the plurality of gas temperatures T _I when the heat generation temperature of the heating element 61 is 100 ° C. the radiation coefficient M _I, the radiation coefficient M _I when the heat producing temperature of the heater element 61 is 0.99 ° C., the radiation coefficient MI when the heat producing temperature of the heater element 61 is 200 ° C. M _I, and the temperature T _I of the gas as independent variables Then, a calorific value calculation formula using the calorific value Q as a dependent variable is calculated.

  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 “A Tutor on Support Vector Regression” by Scholkopf (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 gas property value measurement system 20 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 according to the first embodiment 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 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.. Thereafter, the heat dissipation coefficient calculation module 301 stores the value of the temperature T _I of the first sample mixed gas and the value of the heat dissipation coefficient M _I when the heat generation temperature of the heat generating element 61 is 100 ° C. in the heat dissipation coefficient storage device 401. save. 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 again, 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 heat dissipation coefficient calculation module 301 stores the measured value of the temperature T _I of the second sample mixed gas and the calculated value of the heat dissipation coefficient M _{I in} the heat dissipation coefficient storage device 401.

(F) Thereafter, the loop from step S100 to step S103 is repeated. Accordingly, the value of the third sample mixed gas temperature T _{I and} the value of the heat dissipation coefficient M _I of the third sample mixed gas when the heating temperature of the heating element 61 is 100 ° C., 150 ° C., and 200 ° C., respectively. The value of the temperature T _I of the fourth sample mixed gas and the value of the heat dissipation coefficient M _I of the fourth sample mixed gas in each case where the heating temperature of the heating element 61 is 100 ° C., 150 ° C., and 200 ° C. It 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. Further, the formula creation module 302 receives the values of the temperature T _I of the first to fourth sample mixed gases and the heat generation temperatures of the heating elements 61 from 100 ° C., 150 ° C., and 200 ° C. from the heat dissipation coefficient storage device 401. the value of the radiation coefficient M _I of the first through fourth sample mixed gas when reads.

(G) In step S105, the calorific values Q of the first to fourth sample mixed gas, the value of the temperature T _I of the first through fourth sample mixed gases, the heat producing temperature of the heater element 61 is 100 ° C. Based on the values of the heat release coefficients M _I of the first to fourth sample mixed gases in each case of 150 ° C. and 200 ° C., the formula creation module 302 performs multiple regression analysis. By multiple regression analysis, the formula creation module 302, the radiation coefficient MI when the heat producing temperature of the heater element 61 is 100 ° C. M _I, the radiation coefficient MI when the heat producing temperature of the heater element 61 is 0.99 ° C. M _I, heat generation of the heater element 61 A calorific value calculation formula is calculated with the heat dissipation coefficient M _I and the gas temperature T _I when the temperature is 200 ° C. as independent variables and the calorific value Q as a dependent variable. After that, in step S106, the formula creation module 302 stores the created calorific value calculation formula in the formula storage device 402, and the calorific value calculation formula creation method according to the first embodiment ends.

  As described above, according to the method for creating the calorific value calculation formula according to the first embodiment, it is possible to create a calorific value calculation formula that can uniquely calculate the calorific value Q of the measurement target mixed gas. It becomes possible.

(Second Embodiment)
As shown in FIG. 9, a thermal conductivity storage device 411 is connected to the CPU 300 of the gas property value measurement system 20 according to the second embodiment. Here, FIG. 10 shows the relationship between the heat dissipation coefficient M _I of the mixed gas and the thermal conductivity when currents of 2 mA, 2.5 mA, and 3 mA are passed through the heating element. As shown in FIG. 10, the radiation coefficient M _I and thermal conductivity of the mixed gas is generally in proportion. Therefore, the thermal conductivity storage device 411 shown in FIG. 9, the correspondence between the radiation coefficient M _I and thermal conductivity of the gas introduced into the chamber 101, is previously stored in the approximate equation or a table or the like.

The CPU 300 according to the second embodiment further includes a thermal conductivity calculation module 322. The thermal conductivity calculation module 322 reads the value of the heat dissipation coefficient M _I from the heat dissipation coefficient storage device 401 and reads the correspondence relationship between the heat dissipation coefficient M _{I of} gas and the heat conductivity from the heat conductivity storage device 411. Furthermore the thermal conductivity calculation module 322 calculates the radiation coefficient M _I of the gas, based on the correspondence between the radiation coefficient M _I and thermal conductivity of the gas, the thermal conductivity of the gas introduced into the chamber 101 To do.

Since the other components of the gas property value measurement system 20 according to the second embodiment are the same as those in the first embodiment, the description thereof is omitted. According to the gas property value measurement system 20 according to the second embodiment, it is possible to calculate an accurate thermal conductivity value of the gas based on the heat dissipation coefficient M _I.

(Third embodiment)
As shown in FIG. 11, a concentration storage device 412 is further connected to the CPU 300 of the gas property value measurement system 20 according to the third embodiment. Here, FIG. 12 shows the relationship between the heat dissipation coefficient M _I of propane gas and the concentration when the gas temperature T _I is 0 ° C., 20 ° C., and 40 ° C. As shown in FIG. 12, the radiation coefficient M _I of the gas, the concentration of the gas, is generally in proportional relationship. Therefore, the concentration storage device 412 shown in FIG. 11, the radiation coefficient M _I of the gas introduced into the chamber 101, and the concentration, the correspondence is previously stored in the approximate equation or a table or the like.

The CPU 300 according to the third embodiment further includes a density calculation module 323. The concentration calculation module 323 reads the value of the heat dissipation coefficient M _I from the heat dissipation coefficient storage device 401, and reads the correspondence between the gas heat dissipation coefficient M _I and the concentration from the concentration storage device 412. Further concentration calculation module 323 the radiation coefficient M _I of the gas, based on the correspondence between the radiation coefficient M _I and concentration of the gas to calculate the concentration of the gas introduced into the chamber 101.

Since the other components of the gas property value measurement system 20 according to the third embodiment are the same as those in the first embodiment, description thereof will be omitted. According to the gas property value measurement system 20 according to the third embodiment, based on the radiation coefficient M _I of the gas, it is possible to calculate an accurate value of the concentration of gas.

(Fourth embodiment)
As shown in FIG. 13, the gas property value measurement system 21 according to the fourth embodiment includes a chamber 101 filled with a measurement target mixed gas whose calorific value Q is unknown, and FIGS. 1 and 2. Using the heating element 61, the first temperature measuring element 62, and the second temperature measuring element 63, the value of the temperature T _I of the measurement target mixed gas and the values of the plurality of heat dissipation coefficients M _I of the measurement target mixed gas are measured. The measurement mechanism 10 shown in FIG. 13 is provided. Further, the gas property value measurement system 21 stores a calorific value calculation formula having the gas heat radiation coefficient M _I for the gas temperature T _I and the plurality of heat generation temperatures of the heat generating element 61 as independent variables, and the calorific value Q as a dependent variable. and wherein the storage device 402, into the independent variable of the radiation coefficients M _I of the gas to the independent variables and a plurality of heat producing temperatures of the heater element 61 of the temperature T _I of the calorific value calculation formula of the gas, the temperature T _I of the mixed gas being measured A calorific value calculation module 305 that substitutes the value and the value of the heat dissipation coefficient M _I of the measurement target mixed gas for a plurality of heat generation temperatures of the heating element 61 to calculate the value of the calorific value Q of the measurement target mixed gas.

The formula storage device 402 stores the calorific value calculation formula described in the first embodiment. Here, as an example, a natural gas containing methane (CH ₄ ), propane (C ₃ H ₈ ), nitrogen (N ₂ ), and carbon dioxide (CO ₂ ) is mixed with a sample to create a calorific value calculation formula. The case where it is used as a gas will be described. Further, the calorific value calculation formula, the radiation coefficient M _I of the gas when the heat producing temperature of 100 ° C. of the heater element 61, the radiation coefficient M _I of the gas when the heat producing temperature of the heater element 61 is 0.99 ° C., the heating elements It is assumed that the gas heat radiation coefficient M _I and the gas temperature T _I when the heat generation temperature of 61 is 200 ° C. are independent variables.

In the fourth embodiment, for example, the calorific value Q including methane (CH ₄ ), propane (C ₃ H ₈ ), nitrogen (N ₂ ), and carbon dioxide (CO ₂ ) at an unknown volume ratio is Unknown natural gas is introduced into the chamber 101 as a measurement target mixed 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 measurement target mixed gas before the heating 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. 13. 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 dissipation coefficient calculation module 301 shown in FIG. 13 performs the heat dissipation coefficient M of the measurement target mixed 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 formulas (1) to (4). Calculate the value of _I. Moreover, the radiation coefficient calculation module 301, the heat generation temperature of 150 radiation coefficient M _I of the heater element 61 in thermal equilibrium with the mixed gas being measured produces heat at ° C., and the heating element 61 and heat heat at the heat producing temperature 200 ° C. The value of the heat dissipation coefficient M _I of the gas mixture to be measured that is in equilibrium is calculated. The heat dissipation coefficient calculation module 301 stores the value of the temperature T _I of the measurement target mixed gas and the calculated value of the heat dissipation coefficient M _{I in} the heat dissipation coefficient storage device 401.

Calorific value calculation module 305, the independent variable of the temperature T _I independent variables and the gas of the radiation coefficient M _I of the calorific value calculation formula of the gas, the values of and the temperature T _I of the radiation coefficients M _I of the mixed gas being measured By substituting, the value of the calorific value Q of the measurement target mixed gas is calculated. 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 measurement target mixed gas calculated by the calorific value calculation module 305. The other components of the gas property value measurement system 21 according to the fourth embodiment are the same as those of the gas property value measurement system 20 according to the first embodiment described with reference to FIG. .

  Next, a calorific value measurement method according to the fourth embodiment will be described with reference to the flowchart shown in FIG. In the following example, the case where the heat generating element 61 of the microchip 8 shown in FIG. 13 generates heat at 100 ° C., 150 ° C., and 200 ° C. will be described.

(A) In step S200, the measurement target mixed 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 measured by the temperature T of the measurement target mixed gas before the heating element 61 generates heat. _I is detected. Thereafter, the driving circuit 303 shown in FIG. 13 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.. Figure radiation coefficient calculation module 301 shown in 13 calculates the radiation coefficient M _I of the mixed gas being measured at the heat producing temperature of 100 ° C.. Further, the heat dissipation coefficient calculation module 301 displays the value of the temperature T _I of the measurement target mixed gas and the value of the heat dissipation coefficient M _I of the measurement target mixed gas when the heat generation temperature of the heating element 61 is 100 ° C. Save to. 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. 13 determines 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 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. 13 generates the heat generation element 61 shown in FIGS. Let Radiation coefficient calculation module 301 shown in FIG. 13, the heat generation temperature of the heater element 61 calculates the radiation coefficient M _I of the mixed gas to be measured 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. 13 causes the heat generating element 61 shown in FIGS. Radiation coefficient calculation module 301 shown in FIG. 13, the heat generation temperature of the heater element 61 calculates the radiation coefficient M _I of the mixed gas to be measured 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. 13 receives the gas heat radiation coefficient when the gas temperature T _I and the heat generation temperature of the heat generating element 61 are 100 ° C., 150 ° C., and 200 ° C. from the formula storage device 402. Read the calorific value calculation formula with M _I as an independent variable. Also, the calorific value calculation module 305 receives from the heat dissipation coefficient storage device 401 the measurement target mixed gas when the value of the temperature T _I of the measurement target mixed gas and the heat generation temperature of the heating element 61 are 100 ° C., 150 ° C., and 200 ° C. I read the radiation coefficient M _I of.

(E) In step S204, the calorific value calculation module 305, the independent variable of the temperature T _I of the calorific value calculation formula by substituting the value of the temperature T _I of the mixed gas being measured, the calorific value calculation formula for the radiation coefficients M _I the independent variables and substitutes the value of the radiation coefficient M _I of the mixed gas being measured, to calculate the calorific value Q of the mixed gas being measured. Thereafter, the calorific value calculation module 305 stores the calculated calorific value Q in the calorific value storage device 403, and ends the calorific value measurement method according to the fourth embodiment.

According to the calorific value calculation method according to the fourth embodiment described above, the measurement target mixed gas can be obtained from the measured value of the heat dissipation coefficient M _I of the measurement target mixed gas without using an expensive gas chromatography device or a sonic sensor. It is possible to measure the calorific value Q of the mixed gas.

Natural gas has a different component ratio of hydrocarbons depending on the gas field. Natural gas includes nitrogen (N ₂ ), carbon dioxide (CO ₂ ) and the like 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.

  Conventionally, when collecting the usage fee of natural gas, a method has been used in which charging is performed according to the volume used, not the calorific value Q used for natural gas. However, since the calorific value Q differs depending on the production gas field from which natural gas is derived, it is not fair to charge the volume used. On the other hand, if the calorific value calculation method according to the fourth embodiment is used, the type of gas component is known, but since the volume ratio of the gas component is unknown, natural gas with an unknown calorific value Q, etc. The calorific value Q of the mixed gas can be easily calculated. Therefore, it becomes possible to collect a fair usage fee.

  In the glass processed product manufacturing industry, it is desired to supply natural gas having a constant calorific value Q in order to keep processing accuracy constant when heat-processing glass. For this purpose, the calorific value Q of each natural gas derived from a plurality of gas fields is accurately grasped and adjusted so that the calorific value Q of all natural gas is the same. Supplying gas is being considered. On the other hand, if the calorific value calculation method according to the fourth embodiment is used, it is possible to accurately grasp the calorific value Q of each of the natural gas derived from a plurality of gas fields. The accuracy can be kept constant.

Furthermore, according to the calorific value calculation method according to the fourth embodiment, it is possible to easily know the accurate calorific value Q of the mixed gas such as natural gas, which is necessary when burning the mixed gas. It becomes possible to set the air amount appropriately. Therefore, it is possible to reduce the amount of wasteful carbon dioxide (CO ₂ ) emissions.

Example 1
First, as shown in FIG. 15, 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 (27). The calorific value Q of 28 kinds of sample mixed gases was calculated by the equation (27), 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) ・ ・ ・ (27)

  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 FIGS. 16 and 17, 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, and the error is slight. there were.

(Example 2)
23 types of sample mixed gases with known calorific value Q different from the sample mixed gas used in Example 1 were further prepared. Here, the temperature of the sample mixed gas before being heated by the heating element was set to −10 ° C., 5 ° C., 23 ° C., 40 ° C., and 50 ° C. Next, a calorific value calculation formula that does not include the independent variable of the gas temperature T _I was created with the heat dissipation coefficient M _I as an independent variable and the calorific value Q as a dependent variable. Furthermore, the calorific value Q of the sample mixed gas was calculated using the generated calorific value calculation formula. Then, as shown in FIG. 18, although the calculated calorific value Q has a slight error, it varied depending on the temperature of the sample mixed gas before being heated by the heating element.

Next, as shown in the following equation (28), a calorific value calculation formula was created with the heat dissipation coefficient M _I and the gas temperature T _I as independent variables and the calorific value Q as a dependent variable.
Q = 39.4-5.97 × M _I (100 ° C)-30.3 × M _I (150 ° C) + 34.6 × M _I (200 ° C) + 0.331 × T _I ... (28)
Furthermore, using the generated calorific value calculation formula, the calorific value Q of the sample mixed gas was calculated by substituting the measured values into the independent variables of the heat dissipation coefficient M _I and the gas temperature T _I. Then, as shown in FIG. 19, the calculated calorific value Q did not vary in error regardless of the temperature of the sample mixed gas before being heated by the heating element. The results shown in FIGS. 18 and 19 were obtained by arranging the heat insulating member 18 of the microchip 8 and keeping the substrate 60 of the microchip 8 at 60 ° C. as shown in FIGS. On the other hand, even if the heat insulating material 18 is not used and the substrate 60 of the microchip 8 is not kept warm, the measured values are substituted into the independent variables of the heat dissipation coefficient M _I and the gas temperature T _{I in} the calorific value calculation formula. When the calorific value Q of the mixed gas was calculated, as shown in FIG. 20, the variation in the calculated calorific value Q was slight. Therefore, by adding not only the independent variable of the heat dissipation coefficient M _I but also the independent variable of the gas temperature T _{I to} the calorific value calculation formula, and substituting the measured value for the independent variable of the gas temperature T _I , the heat generation is performed with higher accuracy. It was shown that the quantity Q can be calculated.

(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, in the first and fourth embodiments, the value of the heat release coefficient M _I of the mixed gas at a plurality of heating temperatures of the heating element is used, but instead, the thermal conductivity of the mixed gas at a plurality of heating temperatures. May be used to create a calorific value calculation formula and calculate the calorific value Q. Thus, it should be understood that the present invention includes various embodiments and the like not described herein.

8 Microchip 10 Measuring mechanism 18 Heat insulation member 20, 21 Gas physical property value measurement system 31A, 31B, 31C, 31D Gas pressure regulator 32A, 32B, 32C, 32D Flow control device 50A, 50B, 50C, 50D Gas cylinder 60 Substrate 61 Heat generation Element 62 First temperature measuring element 63 Second temperature measuring element 64 Third temperature measuring element 65 Insulating film 66 Cavity 91A, 91B, 91C, 91D, 92A, 92B, 92C, 92D, 93, 102, 103 101 Chamber 161, 162, 163, 164, 165, 181, 182, 183 Resistance element 170, 171 Operational amplifier 301 Heat dissipation coefficient calculation module 302 Formula creation module 303 Drive circuit 305 Heat generation amount calculation module 312 Input device 313 Output device 322 Thermal conductivity Calculation module 323 concentration calculation Module 401 radiation coefficient storage device 402 formula storage device 403 calorific value storage device 411 thermal conductivity storage device 412 concentration storage device

Claims (36)

A heating element for heating each of the plurality of mixed gases;
A measuring mechanism for measuring a gas temperature value of each of the plurality of mixed gases and a physical property value of each of the plurality of mixed gases when the heating element generates heat at a plurality of heating temperatures;
Based on the known calorific value of each of the plurality of mixed gases, the measured gas temperature value, and the physical property value measured for the plurality of exothermic temperatures, the gas temperature and the plurality of gas temperatures are measured. An equation creation module for creating a calorific value calculation formula with the physical property with respect to the exothermic temperature as an independent variable and the calorific value as a dependent variable;
A calorific value calculation formula creation system.   The calorific value calculation formula creation system according to claim 1, wherein the physical property is a heat dissipation coefficient or a thermal conductivity.   The calorific value calculation formula creation system according to claim 1 or 2, wherein the number of the plurality of heat generation temperatures is a number obtained by subtracting 1 from at least the number of the plurality of types of gas components.   The calorific value calculation formula creation system according to any one of claims 1 to 3, wherein the formula creation module creates the calorific value calculation formula using support vector regression.   The measurement mechanism calculates the heat dissipation coefficient of each of the plurality of mixed gases by dividing the driving power of the heat generating element by the difference between the heat generation temperature of the heat generating element and the gas temperature of each of the plurality of mixed gases. The calorific value calculation formula creation system according to any one of claims 1 to 4, further comprising a heat dissipation coefficient calculation module.   The calorific value calculation formula creation system according to any one of claims 1 to 5, wherein each of the plurality of mixed gases is natural gas.   The calorific value calculation formula creation system according to any one of claims 1 to 6, wherein each of the plurality of mixed gases includes methane, propane, nitrogen, and carbon dioxide as the plurality of types of gas components. Preparing a plurality of gas mixtures containing a plurality of types of gas components;
Measuring a gas temperature value of each of the plurality of mixed gases;
Measuring a value of each physical property of the plurality of mixed gases when the heating element is heated at a plurality of heat generation temperatures;
Based on the known calorific value of each of the plurality of mixed gases, the measured gas temperature value, and the physical property value measured for the plurality of exothermic temperatures, the gas temperature and the plurality of gas temperatures are measured. Creating a calorific value calculation formula with the physical property relative to the exothermic temperature as an independent variable and the calorific value as a dependent variable;
A method for creating a calorific value calculation formula including   The method for creating a calorific value calculation formula according to claim 8, wherein the physical property is a heat dissipation coefficient or a thermal conductivity.   The method of creating a calorific value calculation formula according to claim 8 or 9, wherein the number of the plurality of heat generation temperatures is a number obtained by subtracting 1 from at least the number of the plurality of types of gas components.   The method for creating a calorific value calculation formula according to any one of claims 8 to 10, wherein support vector regression is used in creating the calorific value calculation formula. Measuring each physical property value of the plurality of mixed gases,
Dividing the driving power of the heating element by the difference between the temperature of the heating element and the gas temperature of each of the plurality of mixed gases;
A method for creating a calorific value calculation formula according to claim 8, comprising:   The calorific value calculation formula creation method according to any one of claims 8 to 12, wherein each of the plurality of mixed gases is natural gas.   The method for creating a calorific value calculation formula according to any one of claims 8 to 13, wherein each of the plurality of mixed gases includes methane, propane, nitrogen, and carbon dioxide as the plurality of types of gas components. A measurement mechanism for measuring a gas temperature value of a measurement target mixed gas whose calorific value is unknown, and a physical property value of the measurement target mixed gas when the heating element generates heat at a plurality of heat generation temperatures;
An equation storage device for storing a calorific value calculation formula having the physical properties for the gas temperature and the plurality of exothermic temperatures as independent variables and the calorific value as a dependent variable;
In the independent variable of the gas temperature of the calorific value calculation formula and the independent variable of the physical property with respect to the plurality of exothermic temperatures, the value of the gas temperature of the measurement target mixed gas and the measurement target mixed gas with respect to the plurality of exothermic temperatures A calorific value calculation module for substituting the physical property value and calculating a calorific value of the measurement target mixed gas;
A calorific value measuring system.   The calorific value measurement system according to claim 15, wherein the physical property is a heat dissipation coefficient or a thermal conductivity.   The calorific value measurement system according to claim 15 or 16, 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 measurement target mixed gas.   A calorific value of a plurality of sample mixed gases containing a plurality of types of gas components, a gas temperature value of the plurality of sample mixed gases, and a physical property value of the plurality of sample mixed gases with respect to the plurality of exothermic temperatures. The calorific value calculation formula having the physical property with respect to the gas temperature and the plurality of exothermic temperatures as an independent variable and the calorific value as a dependent variable has been created on the basis of any one of claims 15 to 17. Calorific value measurement system.   The calorific value measurement system according to claim 18, wherein support vector regression is used to create the calorific value calculation formula.   The measurement mechanism calculates the value of the heat dissipation coefficient of the measurement target mixed gas by dividing the driving power of the heat generation element by the difference between the heat generation temperature of the heat generation element and the gas temperature of the measurement target mixed gas. The calorific value measurement system according to any one of claims 15 to 19, further comprising a calculation module.   The calorific value measurement system according to claim 18 or 19, wherein each of the plurality of sample mixed gases is natural gas.   The calorific value measurement system according to any one of claims 18, 19, and 21, wherein each of the plurality of sample mixed gases includes methane, propane, nitrogen, and carbon dioxide as the plurality of types of gas components.   The calorific value measurement system according to any one of claims 15 to 22, wherein the measurement target mixed gas is natural gas.   The calorific value measurement system according to any one of claims 15 to 23, wherein the measurement target mixed gas includes methane, propane, nitrogen, and carbon dioxide.   The calorific value measurement system according to claim 24, wherein the measurement target mixed gas further includes alkane. Measuring the gas temperature value of the measurement target mixed gas whose calorific value is unknown, and the physical property value of the measurement target mixed gas when the heating element generates heat at a plurality of heat generation temperatures;
Preparing a calorific value calculation formula having the physical properties for the gas temperature and the plurality of exothermic temperatures as independent variables and the calorific value as a dependent variable;
In the independent variable of the gas temperature of the calorific value calculation formula and the independent variable of the physical property with respect to the plurality of exothermic temperatures, the value of the gas temperature of the measurement target mixed gas and the measurement target mixed gas with respect to the plurality of exothermic temperatures Substituting the value of the physical property, calculating the calorific value of the measurement target mixed gas,
Method for measuring calorific value, including   The calorific value measurement method according to claim 26, wherein the physical property is a heat dissipation coefficient or a thermal conductivity.   The calorific value measurement method according to claim 26 or 27, wherein the number of the plurality of heat generation temperatures is a number obtained by subtracting 1 from at least the number of the plurality of types of gas components contained in the measurement target mixed gas.   A calorific value of a plurality of sample mixed gases containing a plurality of types of gas components, a gas temperature value of the plurality of sample mixed gases, and a physical property value of the plurality of sample mixed gases with respect to the plurality of exothermic temperatures. 29. The calorific value calculation formula according to any one of claims 26 to 28, wherein the calorific value calculation formula having the physical property with respect to the gas temperature and the plurality of exothermic temperatures as an independent variable and the calorific value as a dependent variable is created. Method of measuring calorific value.   The calorific value measurement method according to claim 29, wherein support vector regression is used to create the calorific value calculation formula. Measuring the physical property value of the measurement target mixed gas,
Dividing the driving power of the heating element by the difference between the heating temperature of the heating element and the gas temperature of the measurement target mixed gas;
The calorific value measuring method according to any one of claims 26 to 30, comprising:   The calorific value measurement method according to claim 29 or 30, wherein each of the plurality of sample mixed gases is natural gas.   The calorific value measurement method according to any one of claims 29, 30, and 32, wherein each of the plurality of sample mixed gases includes methane, propane, nitrogen, and carbon dioxide as the plurality of types of gas components. .   The calorific value measurement method according to any one of claims 26 to 33, wherein the measurement target mixed gas is natural gas.   The calorific value measurement method according to any one of claims 26 to 34, wherein the measurement target mixed gas includes methane, propane, nitrogen, and carbon dioxide.   The calorific value measurement method according to claim 35, wherein the measurement target mixed gas further contains alkane.