JP2009042216A - Calorimetric method and system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a calorimetric method and system capable of measuring the calorie of a target gas with high reliability, regardless of whether the target gas is a natural gas or a biogas. <P>SOLUTION: The present invention is a calorimetric method for measuring the calorie of a gas, including calculating the calorie Q [MJ/Nm<SP>3</SP>] of a target gas, based on the refractive index-converted calorie A [MJ/Nm<SP>3</SP>] obtained from the refractive index of the target gas and the density-converted calorie B [MJ/Nm<SP>3</SP>] obtained from the density of the target gas, according to Equation (1), where 2.40≤α≤3.11. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a calorimetric method and a calorimeter.

  Conventionally, as a calorimeter for measuring the calorific value of a gas, a calorimeter having a configuration for obtaining a calorific value based on the thermal conductivity of a calorimetric gas (hereinafter also referred to as “measured gas”), A configuration that obtains the amount of heat based on the density or a configuration that obtains the amount of heat based on the refractive index of the gas to be measured is used (for example, see Patent Documents 1 to 3).

In the calorimeter with such a configuration, the amount of heat of the paraffinic hydrocarbon gas as the gas to be measured is proportional to the refractive index and density, and is also inversely proportional to the thermal conductivity. The amount of heat is measured.
Thus, according to such a calorimeter, the gas to be measured is only a paraffinic hydrocarbon gas such as a city gas composed of a mixed gas of LNG (liquefied natural gas) and LPG (liquefied petroleum gas), for example. In the case where it is constituted, high reliability is obtained in the calorific value of the gas to be measured.

  However, when the gas to be measured is, for example, natural gas or biogas just produced from a gas field, the natural gas or biogas includes, for example, carbon dioxide gas or monoxide along with paraffinic hydrocarbon gas. It contains a lot of gas other than paraffinic hydrocarbon gas such as carbon gas, nitrogen gas and oxygen gas (hereinafter also referred to as “miscellaneous gas”), and the calorific value of these miscellaneous gases depends on its refractive index, density and Since it does not have a proportional relationship or an inverse proportional relationship with thermal conductivity or the like, there is a problem that a measurement error occurs due to the inclusion of miscellaneous gas.

Japanese Patent Application No. 2-257046 Japanese Patent Application No. 10-38827 Japanese Patent Application No. 8-320300

  The present invention has been made based on the above circumstances, and its purpose is to measure the calorific value of the calorimetric gas with high reliability even if the calorimetric gas is natural gas or biogas. An object of the present invention is to provide a calorimetric method and a calorimetric apparatus that can be used.

The calorimetric method of the present invention is a calorimetric method for measuring the calorific value of a gas,
Based on the refractive index converted heat quantity A [MJ / Nm ³ ] obtained from the refractive index of the calorimetric gas and the density converted heat quantity B [MJ / Nm ³ ] obtained from the density of the calorimetric gas, the following The calorific value Q [MJ / Nm ³ ] of the calorimetric measurement target gas is calculated under the condition of 2.40 ≦ correction coefficient α ≦ 3.11 according to the equation (1).

  In the calorimetric method of the present invention, the value of the correction coefficient α is preferably 2.40 to 2.60 in the equation (1).

  In the calorimetric method of the present invention, the calorimetric gas is mainly composed of at least one of paraffinic hydrocarbon gas and hydrogen gas, and at least one of carbon dioxide gas, carbon monoxide gas, nitrogen gas and oxygen gas. It is preferable that one kind is contained.

  In the calorimetric method of the present invention, the calorimetric gas is preferably natural gas or biogas.

The calorimeter of the present invention includes a refractive index-converted calorimeter for measuring the refractive index-converted calorie of the calorimetric target gas, and a density-converted calorimeter for measuring the density-converted calorie of the calorimetric target gas, With
The calorific value of the calorimetric gas is calculated by the calorimetric method described above.

  According to the calorimetric method of the present invention, the calorific value of the calorimetric target gas is calculated by a specific calculation formula based on the refractive index-converted calorie and density-converted calorie of the calorimetric target gas. And at least one of paraffinic hydrocarbon gas and hydrogen gas, whose calorific value and refractive index and density are in a proportional relationship, and paraffinic hydrocarbon gas whose calorific value does not have a specific correspondence with refractive index and density, and Even when a gas other than hydrogen gas is contained, the measurement error that occurs in the refractive index converted calorific value and density converted calorific value due to the inclusion of gas other than paraffinic hydrocarbon gas and hydrogen gas, It can correct | amend using the relationship between the said refractive index conversion calorie | heat amount and the said density conversion calorie | heat amount. Therefore, the gas for calorimetric measurement contains at least one of paraffinic hydrocarbon gas and hydrogen gas, and gas other than paraffinic hydrocarbon gas and hydrogen gas whose calorific value does not have a specific relationship with the refractive index and density. Even if natural gas or biogas is used, it is possible to prevent measurement errors from occurring in the amount of heat finally obtained due to the inclusion of gas other than paraffinic hydrocarbon gas and hydrogen gas. Therefore, the calorie | heat amount of the said calorimetry object gas can be measured with high reliability.

  According to the calorimeter of the present invention, it is provided with a refractive index-converted calorimeter and a density-converted calorimeter, and is converted into a refractive index measured in the refractive index-converted calorimeter by the calorimetric method of the present invention. Since the heat quantity of the calorimetric gas is calculated based on the calorie and the density-converted calorie measured by the density-converted calorimetry mechanism, the calorimetric gas is at least one of paraffinic hydrocarbon gas and hydrogen gas. Even if it is a natural gas or biogas containing a gas other than paraffinic hydrocarbon gas and hydrogen gas whose calorific value does not have a specific correspondence with the refractive index and density together with one kind, the calorimetric measurement target The amount of heat of gas can be measured with high reliability.

Hereinafter, embodiments of the present invention will be described in detail.
FIG. 1 is an explanatory diagram showing an example of the configuration of the calorimeter of the present invention.
The calorimeter 10 is used, for example, for measuring the calorie of gas flowing in the gas pipeline 12 in the direction of the arrow in FIG.
The calorimeter 10 includes a refractive index-converted calorie measuring mechanism 21 for measuring a refractive index-converted calorie A obtained from a refractive index of a gas to be measured (a calorimetric gas), and a density obtained from the density of the gas to be measured. A density-converted calorie measuring mechanism 23 for measuring the converted calorie B, and a refractive index-converted calorie A obtained by the refractive index-converted calorimeter 21 and a density-converted calorie obtained by the density-converted calorimeter 23. A calculation mechanism 25 for calculating the heat quantity Q of the gas to be measured based on B is provided.
The calorific value Q of the measured gas calculated by the calculation mechanism 25 is transmitted to the display unit 27 through the data transmission path 28, and the calorific value Q of the measured gas is displayed on the display unit 27. The Rukoto.
In FIG. 1, 16A, 16B, and 16C are gas flow paths for supplying the gas flowing through the gas pipeline 12 to each of the refractive index converted calorimeter 21 and the density converted calorimeter 23 as a gas to be measured. . Reference numeral 22 denotes a data transmission path for transmitting the refractive index converted heat quantity A data obtained in the refractive index converted heat quantity measurement mechanism 21 to the calculation mechanism 25, and 24 denotes the density converted heat quantity measurement mechanism 23. This is a data transmission path for transmitting the data of the density-converted heat quantity B to the calculation mechanism 25.

In the calorimeter 10 having such a configuration, the calorific value Q of the gas to be measured is calculated by the calculation mechanism 25 by the calorie measurement method of the present invention (hereinafter also referred to as “specific calorie measurement method”).
That is, according to a specific calorimetric method, the calorie Q of the gas to be measured is 2.40 ≦ correction coefficient α ≦ 3 according to the above equation (1) based on the refractive index converted calorie A and the density calorie B. .11.
Here, in the equation (1), the unit of the calorific value Q of the gas to be measured and the values of the refractive index converted calorie A and density converted calorie B used for the calculation is [MJ / Nm ³ ].

In the formula (1), the correction coefficient α is 2.40 or more and 3.11 or less, but is particularly preferably 2.40 to 2.60.
When the correction coefficient α is too small, the measurement error generated in the refractive index converted heat quantity A and the density converted heat quantity B cannot be sufficiently corrected, and the heat quantity of the gas to be measured finally obtained is miscellaneous. Measurement error due to the inclusion of. On the other hand, when the correction coefficient α is excessive, the measurement error generated in the refractive index converted heat amount A and the density converted heat amount B is not appropriately corrected, and the measurement error is present in the heat amount of the gas to be measured finally obtained. It will occur.

  Further, when the correction coefficient α is 2.40 to 2.60, higher reliability can be obtained in the quantity of heat Q obtained, particularly in the measurement gas made of natural gas or biogas just produced from the gas field. Obtainable.

This correction coefficient α is a value based on the difference in magnitude of measurement error that occurs in the refractive index-converted calorimeter 21 and the density-converted calorimeter 23 due to the inclusion of miscellaneous gas in the gas to be measured, that is, refraction. It is the value of the ratio of the measurement error that occurs in the density-converted heat quantity B to the measurement error that occurs in the rate-converted heat quantity A, and is therefore preferably a suitable value corresponding to the composition of the gas to be measured.
Specifically, as will be apparent from Experimental Example 1 described later, for example, when the miscellaneous gas is only oxygen gas, the correction coefficient α is preferably 3.11, and the miscellaneous gas is only nitrogen gas. In this case, the correction coefficient α is preferably 2.49. When the miscellaneous gas is only carbon dioxide gas, the correction coefficient α is preferably 2.45, and the miscellaneous gas is carbon monoxide gas. In the case of only this, the correction coefficient α is preferably 3.06.

  As the calculation mechanism 25, for example, a personal computer, a recorder with a calculation function, or the like can be used.

  As the refractive index converted calorie measuring mechanism 21 for obtaining the refractive index converted calorie A, for example, a difference in refractive index of light between a gas to be measured and a standard gas such as air is detected as a displacement of the interference fringe, and this interference fringe is detected. The apparatus of the structure which measures the refractive index conversion calorie | heat amount A of to-be-measured gas based on the displacement amount of can be used.

  As a specific example of the apparatus constituting the refractive index conversion calorie measuring mechanism 21, as shown in FIG. 2, a measurement target gas cell unit 32 for introducing a gas to be measured and a standard gas such as air are used. A chamber 31 in which standard gas cell portions 33 and 34 for filling are partitioned, a parallel plane mirror 36 that divides the light from the light source 35, and light that has been split by the parallel plane mirror 36 and that has passed through the chamber 31 is reflected. By changing the traveling direction of the prism 41 and passing through the chamber 31 again, it is superimposed on the parallel plane mirror 36 to generate interference fringes, and the prism 41 arranged and adjusted on the parallel plane mirror 36. And an interference fringe detecting means 37 for receiving the combined light (interference light) superimposed on each other. In FIG. 2, 39 is a plane mirror that reflects the combined light, and 42 is a condensing lens for condensing the combined light, and an interference fringe detecting means 37 is disposed at the focal position of the condensing lens 42. Further, a one-dot chain line arrow indicates a path until the light from the light source 35 is received by the interference fringe detector 37.

  As the density-converted calorie measuring mechanism 23 for obtaining the density-converted calorie B, for example, the resonance frequency when a vibrating tube made of a thin cylindrical body is vibrated in the measured gas changes based on the density of the measured gas. Thus, an apparatus configured to measure the density-converted heat quantity B of the gas to be measured based on the amount of change in the resonance frequency can be used.

  In the calorimeter 10 having such a configuration, during the measurement operation, the gas flowing through the gas pipeline 12 through the gas flow paths 16A, 16B, and 16C serves as a gas to be measured, and the refractive index conversion calorimeter 21 and By being supplied to each of the density-converted calorie measuring mechanisms 23, the refractive index-converted calorie measuring mechanism 21 measures the refractive index-converted calorie A, while the density-converted calorie measuring mechanism 23 measures the density-converted calorie B. Is done. These measured values are transmitted to the calculation mechanism 25 via the data transmission paths 22 and 24, respectively. In the calculation mechanism 25, the heat quantity Q is calculated based on the refractive index converted heat quantity A and the density converted heat quantity B. Is done. The heat quantity Q thus obtained is transmitted to the display unit 27 via the data transmission path 28 and displayed on the display unit 27.

The calorimeter 10 as described above uses a gas whose calorific value is proportional to the refractive index and density, that is, a gas whose main component is at least one of paraffinic hydrocarbon gas and hydrogen gas as a measurement gas. It is.
Specifically, the gas to be measured includes a gas containing at least one kind of paraffinic hydrocarbon gas and hydrogen gas, and a main component composed of at least one kind of paraffinic hydrocarbon gas and hydrogen gas. As the component, at least one of carbon dioxide gas, carbon monoxide gas, nitrogen gas and oxygen gas is contained as a miscellaneous gas.

  Specific examples of the gas to be measured include natural gas, biogas, and the like, and also include coal gas, gas generated in the iron making process, gas generated in the coal mine, and the like. Here, as an example of coal gas, for example, methane gas 27%, CnHm (where n is an integer of 2 or more, m is an integer) 2%, carbon monoxide gas 6%, hydrogen gas 56%, carbon dioxide A gas containing 3% gas, 1% oxygen gas and 5% nitrogen gas may be mentioned. Moreover, as an example of the gas generated in the iron making process, for example, CpHq (p and q each represent an integer) 0.3%, carbon monoxide gas 28%, hydrogen gas 2.7%, carbon dioxide gas Examples include gases containing 0.05% and nitrogen gas 58.5%. Moreover, as an example of the gas generated in the coal mine, for example, a gas containing 52.4% methane gas, 4.6% carbon dioxide gas, 7% oxygen gas, and 36% nitrogen gas can be given.

  However, the calorimeter 10 uses the calculation mechanism 25 according to a specific calorimetry method, the refractive index conversion calorie A obtained by the refractive index conversion calorimeter 21 and the density conversion obtained by the density conversion calorimeter 23. Since the calorific value Q of the gas to be measured is calculated by the equation (1) based on the calorie B, the gas to be measured is a paraffinic system in which the calorific value, refractive index and density are in a proportional relationship. A gas other than paraffinic hydrocarbon gas and hydrogen gas whose main component is at least one of hydrocarbon gas and hydrogen gas and whose calorific value does not have a specific correspondence with refractive index and density (other gases) ) Is produced in the refractive index-converted calorimeter 21 and the density-converted calorimeter 23 as the miscellaneous gas is contained. The measurement error can be corrected by using the measurement error related to the refractive index in terms of calorimetry mechanism 21, the relationship between the difference in the magnitude of measurement errors in accordance with said density conversion calorimetry mechanism 23.

Therefore, according to the calorimeter 10, the gas to be measured includes a large amount of miscellaneous gas whose paraffinic hydrocarbon gas and the calorific value thereof do not have a specific correspondence with the refractive index and density. Even if it is natural gas, biogas, etc. that have just been produced from, it is possible to suppress the occurrence of measurement errors in the amount of heat finally obtained due to the inclusion of miscellaneous gas. The amount of heat Q of the measurement gas can be measured with high reliability.
In addition, the calorimeter 10 can measure the calorie with high reliability even when the gas to be measured is made of only a paraffinic hydrocarbon gas such as a city gas made of a mixed gas of LNG and LPG. Measurements can be made.

  Furthermore, according to the calorific value measuring apparatus 10, even if the kind and concentration of miscellaneous gas in the gas to be measured change greatly due to various circumstances such as environmental conditions and supply gas supply switching in the gas pipeline 12, the change is observed. It can correspond to.

Although the calorific measurement method and calorimeter of the present invention have been specifically described above, the present invention is not limited to the above examples, and various modifications can be made.
For example, the calorimetric method is not limited to being implemented by an apparatus comprising a refractive index-converted calorimeter, a density-converted calorimeter, and a calculation mechanism. If the calorific value Q of the gas to be measured is calculated under the condition of 2.40 ≦ correction coefficient α ≦ 3.11 based on the above equation (1), the refractive index-converted calorie A and density-converted calorie B The device for obtaining the value may be individual without being integrated, and the method for calculating the calorie Q of the gas to be measured may be automatic calculation by a computing machine or manual calculation. May be.

  Hereinafter, experimental examples of the present invention will be described.

[Experimental Example 1]
Oxygen gas, nitrogen gas, carbon dioxide gas, and carbon monoxide gas are used as sample gases. For each sample gas, the amount of heat (refractive index converted heat amount) obtained based on the refractive index by a refractive index calorimeter and the density formula The calorimeter measures the calorie obtained based on density (density calorie), and based on this measured value and the calorie obtained by analysis using a gas chromatograph, the refractive index calorie and the density calorie While confirming the measurement error that occurs in each, the measurement error that occurred in the refractive index conversion calorie (hereinafter also referred to as “refractometer error”) and the measurement error that occurred in the density conversion calorie (hereinafter “density meter error”) The error ratio (density meter error / refractometer error) was calculated. The results are shown in Table 1 below.
In Table 1, “refractometer error” is a measurement error that occurs per 1% by volume of sample gas in terms of refractive index converted heat, and “density meter error” is 1% by volume of sample gas in terms of density converted heat. This is a measurement error that occurs on hit.

From the results shown in Table 1, the density meter error is larger than the refractometer error in any of the sample gases of oxygen gas, nitrogen gas, carbon dioxide gas and carbon monoxide gas. It was confirmed that the ratio of the density meter error to the error shows a specific value depending on the type of sample gas.
Therefore, based on the results of Experimental Example 1, the calorific value of the calorimetric gas is calculated based on the refractive index-converted calorie and the density-converted calorie of the calorimeter gas, and the correction coefficient α is set to 2.40-3. It was confirmed that the measurement can be performed with high reliability by setting the range to 11.

It is explanatory drawing which shows an example of a structure of the calorie | heat amount measuring apparatus of this invention. It is explanatory drawing which shows an example of a structure of the apparatus used as a refractive index conversion calorie | heat amount measuring mechanism which comprises the calorimeter of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Calorie measuring device 12 Gas pipeline 16A, 16B, 16C Gas flow path 21 Refractive index conversion calorie measurement mechanism 22 Data transmission path 23 Density conversion calorie measurement mechanism 24 Data transmission path 25 Calculation mechanism 27 Display part 28 Data transmission path 31 Chamber 32 Measurement Target gas cell part 33, 34 Standard gas cell part 35 Light source 36 Parallel plane mirror 37 Interference fringe detection means 39 Plane mirror 41 Prism 42 Condensing lens

Claims (5)

A calorimetric method for measuring the calorific value of a gas, comprising:
Based on the refractive index converted heat quantity A [MJ / Nm ³ ] obtained from the refractive index of the calorimetric gas and the density converted heat quantity B [MJ / Nm ³ ] obtained from the density of the calorimetric gas, the following A calorific value measuring method, wherein the calorific value Q [MJ / Nm ³ ] of the calorimetric target gas is calculated by the equation (1) under the condition of 2.40 ≦ correction coefficient α ≦ 3.11.

  The calorific value measurement method according to claim 1, wherein the value of the correction coefficient α in the formula (1) is 2.40 to 2.60.   The calorimetric gas is mainly composed of at least one of paraffinic hydrocarbon gas and hydrogen gas, and contains at least one of carbon dioxide gas, carbon monoxide gas, nitrogen gas and oxygen gas. The calorimetric method according to claim 1 or claim 2.   The calorific value measuring method according to any one of claims 1 to 3, wherein the calorimetric gas is natural gas or biogas. A refractive index-converted calorimeter for measuring the refractive index-converted calorie of the calorimetric gas, and a density-converted calorimeter for measuring the density-converted calorie of the calorimetric gas,
The calorie | heat amount measuring apparatus by which the calorie | heat amount of calorie | heat_measurement object gas is computed by the calorie | heat amount measuring method in any one of Claims 1-4.

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