JP2000039425A - Gas physical property-measuring device and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an easy-to-use gas physical property-measuring device where, for example, a timing for replacing operation cannot be limited. SOLUTION: A device is provided with a measurement pipe 70 where a gas to be measured is introduced and flows in the direction of a pipe axis inside, at the same time a detection part of a pair of ultrasonic transceiver 15a in parallel with the flow of the gas to be measured in the measurement pipe while they oppose each other, and a sound speed-deriving means 18 for capturing propagation time where ultrasonic waves are propagated in the flow of the gas to be measured from one ultrasonic transceiver 15a to the other 15a bi-directionally and for obtaining the sound speed of the gas to be measured according to the obtained pair of propagation time. Further, the device is provided with at least one of calory-deriving means 20a for obtaining the amount of generated heat of the gas to be measured according to a sound speed obtained from the sound speed-deriving means 18, a specific gravity-deriving means 20b for obtaining the specific gravity of the gas to be measured, or a Wobbe index-deriving means 20c for obtaining the Wobbe index of the gas to be measured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas physical property measuring apparatus and a measuring method thereof which can be used effectively when producing or supplying calorie-adjusted product gas or unheated gas (non-caloric gas). About the method,
The present invention relates to a substance whose physical properties are a calorific value, a specific gravity or a Wobbe index of a gas to be measured.

[0002]

2. Description of the Related Art The inventors of the present application have proposed to measure the calorific value of a gas to be measured by measuring the sound velocity thereof (Japanese Patent Application Nos. 8-343015 and 8-343).
019, Japanese Patent Application No. 8-343020). The measurement principle regarding the basic calorific value is to determine the calorific value from the obtained sound speed, and the specific configuration of a pipe insertion type sound speed measuring mechanism equipped with an ultrasonic transceiver for measuring the sound speed is described in Examples. I have. In this example, a configuration is adopted in which a detection unit of an ultrasonic transceiver (the detection unit is provided with an ultrasonic transmission unit and a reception unit) is provided at a specific portion of the pipe.
Therefore, in the case of this configuration, a pipe having the same diameter as the pipe to be measured is prepared, a pair of holes are drilled in a predetermined portion of the pipe, and a pair of detection units are positioned in this hole, and a mechanism is constructed. Will be done.

[0003]

However, this configuration has the following problems. (1) When replacing an existing pipe, it is necessary to manufacture a pipe insertion type calorific value measuring device equipped with an ultrasonic transceiver in accordance with the diameter of the pipe, which is not suitable for mass production. (2) When replacing existing pipes, care must be taken not to affect the operation, and the time for replacement work will be limited. (3) In the case of the pipe insertion type, it is necessary to stop the gas flow at the time of inspection, which may affect the actual operation. Accordingly, an object of the present invention is to overcome the above disadvantages.

[0004]

The gas measuring apparatus according to the present invention for achieving the above object has a characteristic configuration in which a measuring pipe into which a gas to be measured flows is introduced and flows in the axial direction of the pipe. In parallel with the flow of the gas to be measured in the above, or at both ends of the measuring tube facing each other in the tube axis direction, a measuring tube provided with a pair of ultrasonic transmitters and receivers facing each other is provided. Then, the propagation time during which the ultrasonic wave propagates in the flow of the gas to be measured from one ultrasonic transceiver to the other ultrasonic transceiver is bidirectionally captured, and the sound velocity of the gas to be measured is obtained from the obtained pair of propagation times. The calorific value deriving means for calculating the calorific value of the gas to be measured, the specific gravity deriving means for calculating the specific gravity of the gas to be measured, or the Wobbe index of the gas to be measured, from the sound speed obtained by the sound speed deriving means, Any one or more of the Wobbe index deriving means to be obtained is provided. The gas measuring device having this configuration includes a measuring tube, and the gas to be measured flows in the measuring tube in the tube axis direction. Then, the detection units of the pair of ultrasonic transceivers are located at positions facing each other in the tube axis direction. In other words, the propagation direction of the ultrasonic wave is set parallel to the flow direction of the gas to be measured. Therefore, the ultrasonic wave can be propagated between these detecting units from one detecting unit side to the other detecting unit side. In this configuration, ultrasonic waves are mutually transmitted from one of the ultrasonic transceivers to the other,
The propagation times in both directions are detected, and the sound speed of the gas to be measured is determined according to the detection results of the propagation times. This is the role of the sound velocity deriving means. When the sound speed is determined, the calorific value, specific gravity, and Wobbe index of the gas to be measured are obtained from the sound speed by the corresponding means, and the physical properties of the gas to be measured obtained from these means are output. here,
Regarding the calorific value, specific gravity, and Wobbe index, which are the measurement targets of this gas measurement device, these values are related to the sound speed of the gas. Can be determined.

In such a configuration, the measurement pipe is provided independently, and a pair of ultrasonic transceivers are provided in parallel with the flow of the gas to be measured, so that the pipe is not caught by the existing pipe. The specifications of the gas measuring device, such as the specifications of the measuring tube and the mounting specifications of the ultrasonic transceiver mounted on the measuring tube, can be determined. Therefore, in the gas measuring device of the present application, if a gas measuring device having a predetermined specification is manufactured, mass production becomes possible, and standardization of the manufacturing can be achieved. In addition, as a specification, by reducing the size, the existing piping is not affected, the space occupied by the space can be saved, and the options for the installation location can be expanded. When replacing with a conventional existing calorific value measuring device, the gas measuring device of the present application is attached to a small-diameter branch pipe branched from the existing pipe, and a structure for guiding the gas to be measured is provided. If the valve is closed, it can be installed or maintained without interrupting the flow of gas in the existing piping, in other words, without hindering operation, and
It is possible to eliminate the timing restriction for performing the work.
More specifically, if the measuring pipe is made to have a pressure resistance to a high pressure and manufactured in a small-sized specification such as a pipe diameter of 25 A and a pipe length of 20 cm, the gas after the measurement is in a state with almost no pressure loss. The measured gas can be returned to the low-pressure line, and the measurement gas recovery device required for the existing calorimeter can be omitted. In addition, since the line is different from the high-pressure line, maintenance of the calorific value measuring apparatus of the present invention can be performed without stopping gas flowing through the high-pressure line.

In order to construct the gas measuring device having the above configuration, an inlet for introducing the gas to be measured and a measurement port for introducing the gas to be measured into a side wall of the measuring tube for the purpose of introducing and deriving the gas to be measured into the measuring tube. It is preferable that a configuration is provided that includes an outlet that guides out the measurement target gas that has flowed in the pipe in the axial direction.
In the case of this configuration, introduction of the gas to be measured into the measuring tube,
The extraction is performed at the side of the tube, and the tube end face in the tube axis direction of the measurement tube can be used as the arrangement portion of the detection unit of the ultrasonic transceiver, so that a compact and easy-to-use measurement tube can be constructed.

The method of measuring the predetermined physical quantity (heat value, specific gravity or Wobbe index) of the gas in this apparatus is performed through the following steps. A straight measuring tube into which the gas to be measured is introduced and which flows through the inside of the measuring tube. At both ends of the measuring tube facing each other in the tube axis direction, a measuring tube provided with a pair of ultrasonic transceivers, with the detecting portions facing each other. Is used to capture in both directions the propagation time of ultrasonic waves propagating in the flow of the gas to be measured from one ultrasonic transceiver to the other ultrasonic transceiver and obtain the measurement from the pair of obtained propagation times The sound speed of the gas to be measured is obtained, and the calorific value of the gas to be measured, the specific gravity of the gas to be measured, or the Wobbe index of the gas to be measured is obtained from the sound speed obtained.

Further, the gas to be measured is preferably a mixed gas containing methane as a main component and a hydrocarbon gas other than methane. Here, the target gas mixture tends to increase its calorific value due to an increase in the content of hydrocarbon gas other than methane, and conversely, the sound speed decreases. Therefore, by utilizing this phenomenon, the sound velocity of the gas to be measured can be measured, and the physical properties can be determined from this. For example, taking the calorific value as an example, as shown in FIG. 4, in natural gas, for example, the sound velocity and the calorific value can be expressed by a primary or secondary correlation equation. Therefore, when measuring the calorific value, the calorific value is calculated from the speed of sound according to a relation index determined in advance. Regarding the specific gravity, this relationship is almost satisfied. Further, since the Wobbe index is an index related to the calorific value and the specific gravity, such a relationship holds. As a result, it has become possible to satisfactorily measure the physical properties of this kind of mixed gas, which is usefully used as city gas today.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 schematically illustrates a configuration in which a gas measuring device 1 of the present application is provided in a gas production facility 2. The gas production facility 2 includes a supply flow path 5 having an LNG tank 3 and an LNG vaporizer 4 on the upstream side,
An adjusting gas addition mechanism 6 for adding a calorie adjusting petroleum gas to the supply flow path 5, and a gas physical quantity (calorific value, calorific value, etc.) of a product gas provided downstream of the adjusting gas addition mechanism 6.
A measuring unit 7 for measuring specific gravity, Wobbe index) is provided.
The measuring section 7 is provided with a measuring pipe 7 provided in the gas measuring device 1.
Reference numeral 0 denotes a portion where the product gas is introduced into the measurement pipe 70 from the gas supply flow path 5 through a pair of branch pipes 71 and is extracted therefrom. Here, this measuring tube 70
Inside, a structure in which the product gas flows in the tube axis direction is adopted. This product gas is the gas measuring device 1 of the present application.
Is a gas to be measured to be measured.

[0010] In this gas production facility 2, the measuring section 7
The gas physical quantity (for example, the calorific value) of the product gas is obtained on the basis of the measurement information obtained in the step (a), and from the relationship between this calorific value and the target calorific value that is the calorific value required for the product gas, the adjustment gas addition The mechanism 6 is configured to generate an adjustment control command. In the gas measuring device 1 of the present application, the calorific value of the gas to be measured,
It is possible to measure specific gravity and Wöbbe index. The gas production facility 2 is configured to provide feedback on the calorific value, so that the calorific value quality of the product gas can be kept good. Here, the heat generation amount control is continuous control of online and on-time.

In order to make the above control possible, a natural gas flow rate measurement for measuring a natural gas flow rate in the supply flow path 5 upstream of the junction 8 of the adjusting gas addition mechanism 6 is described. A vessel 9 is provided. On the other hand, the above-described adjusting gas addition mechanism 6 includes an addition flow path 12 provided with an LPG tank 10 and an LPG vaporizer 11 on the upstream side, and a flow control valve 13 and a petroleum gas flow rate. A measuring device 14 is provided. In the facility 2, the flow rate of the natural gas and the flow rate of the petroleum gas with respect to the natural gas are constantly monitored, and it is possible to detect the quantity ratio of the natural gas and the petroleum gas that is sent out in a mixed state downstream of the supply flow path. When it is necessary to control the calorific value of the product gas as in the present application, this quantity ratio becomes a problem.
By appropriately adjusting the opening degree of No. 3, it is possible to adjust the flow rate ratio between the two (and, consequently, the calorific value).

The gas production facility 2 is provided with a supply passage 5 through which a base gas raw material containing methane as a main component (natural gas in this example) flows.
An adjusting gas addition mechanism 6 for adding a calorie adjusting gas raw material (in this example, petroleum gas) having a larger calorific value than methane while adjusting the addition amount is provided to obtain a calorie-adjusted product gas. . Further, a heat generation amount control device 100 for the adjustment gas addition mechanism 6 is provided. As shown in FIGS. 1 and 2, the ultrasonic flow meter 15 having the ultrasonic transmitter / receiver provided in the measurement unit 7 and the thermometer 16
a, a pressure gauge 16b, and means for generating the adjustment control command according to measurement information from these instruments. This means is constructed using a microcomputer, a semiconductor memory, and the like as main devices. Briefly describing this means, as shown in FIG.
a, an index generating means 17b, a sound velocity measuring means 19 provided with the ultrasonic current meter 15 and a sound velocity deriving means 18, a calorific value deriving means 20a, a specific gravity deriving means 20b, a Wobbe index deriving means 20c, and an adjustment control command generating means 21. Have. Here, the storage unit 17a stores information necessary for deriving the calorific value and the specific gravity, and the index generating unit 17b uses the information stored in the storage unit 17a to calculate a sound speed-calorific value related index,
A sound speed-specific gravity relationship index is generated, and the sound speed measuring means 19 obtains a sound speed of the product gas. The calorific value deriving means 20a derives a calorific value from the sound velocity obtained by the sound velocity measuring means 19, and the specific gravity deriving means 20b derives specific gravity from the sound velocity obtained by the sound velocity measuring means 19, The Wobbe index deriving unit 20c derives a Wobbe index from the calorific value derived by the calorific value deriving unit 20a and the specific gravity derived by the specific gravity deriving unit 20c. further,
The adjustment control command generation means 21 generates an adjustment control command from the obtained heat value. The gas measuring device 1 of the present application is provided with all means except the adjustment control command generating means 21.

Hereinafter, the configuration and operation of each means will be described in more detail. The storage means 17a stores a sound speed-calorific value relationship index, a sound speed-specific gravity relationship index obtained from a relationship between a sound speed, a calorific value, and a specific gravity of each of a plurality of standard gases in which a base gas and a calorific value adjusting gas are mixed at different ratios. Is stored. FIG. 4 shows an example of such a sound speed-calorific value relation index. In the figure, a correlation line (represented by a first-order correlation expression and a second-order correlation expression) indicated by a solid line and a broken line corresponds to this index. The sound velocity-calorific value relation index is obtained from the information stored in the storage unit 17a.
It is automatically generated by the index generation means 17b based on the measurement result of the temperature and pressure of the product gas. These temperature and pressure information can be obtained from the thermometer 16a and the pressure gauge 16b. Similarly, the sound speed-calorific value relation index is automatically generated by the index generation means 17b. For this purpose, the storage means 17 stores in the storage means 17 a sound speed-temperature-pressure relationship index for a plurality of standard gases whose calorific values and specific gravities are known in advance (shown in FIG. 3. Has been
The calorific value and specific gravity are interchangeable (they are uniquely determined for the same gas), and the index generation unit 17b uses the stored information to determine a plurality of values according to the temperature and pressure of the product gas. From the sound velocity-temperature-pressure relationship index of
In this state, a relation index between the sound speed and the heat value or specific gravity (a sound speed-heat value relation index is shown in FIG. 4) is automatically generated. That is, the sound speed with respect to the standard gas having each calorific value is obtained from the sound speed-temperature-pressure relationship panel shown in FIG. 3, and the sound speed and the heat speed are arranged as shown in FIG. Generated as a quantity-related index. By using this index, for example, when the sound speed is determined, the calorific value of the gas can be derived from the sound speed as shown by the dashed line with the arrow in FIG. Similar processing is possible for specific gravity.

The sound velocity measuring means 19 includes the above-described ultrasonic velocity meter 15 and the sound velocity deriving means 18. From the ultrasonic flow meter 15, the flow velocity of the product gas flowing in the measurement tube 70 is obtained, and a pair of propagation times T21 and T12 are obtained in measuring the flow velocity. Ultrasonic current meter 1
2 will be described with reference to FIG. 2. The measuring device 5 includes a measuring tube 70 on a straight pipe through which a gas to be measured flows in the direction of the tube axis. A pair of ultrasonic transceivers 15a are provided at opposite ends so that the detection units face each other. Here, since the pair of ultrasonic transceivers 15a are disposed at different positions in the axis Z direction of the flow path, the ultrasonic waves passing between the two are affected by the flow velocity v and propagate from the upstream side to the downstream side. The propagation time of the ultrasonic wave is accelerated, and vice versa. The configuration for introducing the gas to be measured into the measuring pipe 70 will be described. The branch pipe 71 is independently connected to an inlet 72 and an outlet 73 provided on the side wall of the measuring pipe 70. The measurement target gas flowing from the port 72 flows through the measurement pipe 70 and returns to the main pipe side via the outlet port 73. In the current meter 15, one ultrasonic transceiver 15a is connected to the other ultrasonic transceiver 1a.
5a captures the propagation time of the ultrasonic wave propagating in the flow of the product gas in two directions (the ultrasonic wave propagation time T21 from the upstream to the downstream, and the ultrasonic wave propagating in the opposite direction). , The flow velocity of the product gas is measured from the pair of obtained propagation times. Therefore, in the ultrasonic current meter 15, as the measurement information, the flow velocity v,
The pair of propagation times T21 and T12 are obtained.

The above-mentioned sound velocity deriving means 18 is configured to be able to derive the sound velocity of the product gas from a pair of measured propagation times of the product gas. In this derivation process, the sound velocity C is obtained from the pair of propagation times T21 and T12.
Since the positional relationship between the pair of ultrasonic transceivers 15a provided in the above-described ultrasonic velocity meter 15 is fixed, the propagation times T12 and T21 that propagate between the transceivers are expressed by the following formulas (1) and (2).
Equation 2 can be described. Here, L is half the distance of the propagation path shown in FIG. 2, C is the speed of sound, and v is the flow velocity of the product gas.

[0016]

(Equation 1)

Since Equations 1 and 2 are simultaneous equations, as shown in Equations 3 and 4, the sound velocity C and the flow velocity v can be obtained from the pair of propagation times T12 and T21.
That is, the above-described sound velocity deriving means obtains the sound velocity C from the pair of propagation times T12 and T21 by performing the processing of Expression 3.

[0018]

(Equation 2)

Next, the role of the calorific value deriving means 20 will be described. As shown by an alternate long and short dash line with an arrow in FIG.
From the sound speed of the product gas obtained by the sound speed measuring means 20, the calorific value of the product gas is obtained based on a sound speed-calorific value correlation index automatically generated from the information stored in the storage means 17.

The above description is mainly about the calorific value. Hereinafter, the specific gravity and the Wobbe index will be described. Instead of the above-described sound velocity-heat generation amount relation index, the sound velocity-specific gravity relation index can be similarly obtained by replacing the heat generation amount with the specific gravity. That is, the storage unit 17a
In addition, a sound velocity-temperature-pressure relation index relating to a plurality of standard gases whose specific gravities are known in advance is stored, and based on the stored information, the index generation unit 17b generates a plurality of sound velocity based on the temperature and pressure of the product gas. From the temperature-pressure relationship index,
The relation index between the sound speed and the specific gravity in this state is automatically generated. Then, the specific gravity deriving means 20b described above can calculate the specific gravity of the product gas from the sound velocity of the product gas separately obtained by the sound velocity measuring means 20, based on the sound velocity-specific gravity correlation index. In this way, the specific gravity of the on-time product gas can be measured.

Further, when the calorific value and specific gravity of the product gas are determined, the Wobbe index of the product gas (gas to be measured) is determined by using these physical properties and dividing the calorific value by the square root of the specific gravity. be able to. This operation derivation is
This is performed by the Wobbe index deriving means 20c. That is, the Wobbe index of the gas to be measured is determined based on the calorific value and the specific gravity obtained from each of the calorific value deriving means 20a and the specific gravity deriving means 20b.

The calorific value of the product gas thus determined is compared with the target calorific value of the product gas, and the above-described adjustment control command is generated. The adjustment control command generation means 21 plays the role of this generation. On the other hand, the obtained physical property values are output as needed. The above is the gas production facility 2
This is the basic configuration.

Therefore, the calorific value measurement and calorific value control of the facility 2 are performed by controlling the sonic velocity, which is the relationship between the sonic velocity of each of a plurality of standard gases in which the base gas and the calorific value adjusting gas are mixed at different ratios, and the calorific value. A calorific value-related index is determined in advance, the sound velocity of the product gas is determined, and the calorific value of the product gas is determined from the determined sound velocity of the product gas (gas to be measured) based on the sound velocity-calorific value relation index. Based on the difference between the calorific value of the product gas thus obtained and the target calorific value, the amount of the calorie-adjusting gas material added to the base gas material is controlled. In addition, the gas measuring device 1 to which the present invention is directed can be applied to the calorie-adjusted product gas manufactured with the calorific value adjustment as described above, and can also control the calorific value by bypassing the adjusting gas addition mechanism 6. Needless to say, it can also be used for measuring the calorific value of the production gas in the production facility for producing the unheated gas without performing the above.

In the following, experiments and actual measurement results performed by the inventors when the measurement method of the present application is adopted will be described. 1. Sound velocity-temperature-pressure relation index (table) This index is a relation index as shown in FIG. 3, and in order to obtain this relation index, nine kinds of heat values and specific gravities are used in principle as parameters. Was used as a standard gas. Table 1 shows the composition (%), calorific value and specific gravity of these standard gases.

[0025]

[Table 1]

These standard gases contain 80 as their main components.
% Of methane, and is a mixed gas obtained by adding and mixing a calorific value adjusting gas (hydrocarbon gas having 2 or more carbon atoms) to the base gas (methane) to adjust the calorific value. The sound velocity in a predetermined state (temperature / pressure state) can be measured using these mixed gases. For each of the above standard gases, four states (5, 15, 25,
35 ° C), and 4 states (10, 20, 30,
40 kgf / cm ² ) for each state (16 states)
I asked for the speed of sound. As shown in FIG. 3 and each table,
The speed of sound could be expressed by a linear relation of temperature with pressure as a parameter. Therefore, as shown in Table 2 below, the coefficients a and b of the linear relationship between the sound speed and the temperature were obtained for each standard gas and each pressure, and the information was stored in the storage means 17a described above. Therefore, the storage means 17
The relation index corresponding to FIG. 3 is stored and stored in “a”, and using this index, a sound velocity-calorific value relation index and a sound velocity-specific gravity relation index can be derived.

[0027]

[Table 2]

2. Sound velocity-calorific value relation index (table) This index is automatically generated by the index generation means 17b described above. In this process, a specific temperature / pressure is specified in the sound velocity-temperature-pressure relation index (table) obtained as described above. And
Recall the speed of sound from each different table corresponding to each standard gas with a different calorific value. Then, across each table in FIG. 3 (in the direction in which the tables overlap), a specific temperature
By reading the speed of sound at the pressure, the related index of FIG. 4 is obtained. However, in the figure, the vertical axis and the horizontal axis are reversed. In this manner, the correlation line between the sound speed and the heat value (FIG. 4)
By obtaining the solid line (first-order correlation equation) and the broken line (second-order correlation equation), the relationship index between the two in a specific temperature and pressure state can be obtained.

Using this sound speed-calorific value relation index,
If the temperature, pressure, and sound speed of the product gas are known, the calorific value of the gas can be obtained. The error of the calorific value obtained by such a method is as follows.
cal / Nm ³ , 15 kcal / N
m ^3, which is equivalent to or better than the conventional method using a hydrometer.

3. Sound velocity-specific gravity relation index (table) This index is also automatically generated by the index generation means 17b described above. In this process, a specific temperature / pressure is designated in the sound velocity-temperature-pressure relation index (table) obtained in the same manner as described above. Then, the speed of sound is called from each of the different tables corresponding to each standard gas having a different specific gravity. By reading the sound speed at a specific temperature and pressure across each table (in the direction of table overlap) in FIG. 3 (however, the calorific value is replaced by the specific gravity), the specific gravity corresponding to FIG. A relation index can be obtained. In this way, by obtaining a correlation line between the sound speed and the specific gravity, a relation index between the two at a specific temperature and pressure state can be obtained.

Therefore, if the temperature, pressure, and sound speed of the product gas are determined by using the sound speed-specific gravity relationship index, the specific gravity of the gas can be obtained. The error of the specific gravity obtained by such a method is that the specific gravity is 0.555 to 0.713.
(Unit: dimensionless) within the range of about ± 0.4 (unit:%), and can achieve the same or better accuracy than the conventional method using a hydrometer. Was.

[Another Embodiment] (a) In the above embodiment, a sound velocity-heat generation amount relation index and a sound velocity-specific gravity relation index are automatically generated from a sound velocity-temperature-pressure relation index previously obtained. However, a sound speed-calorific value relationship index and a sound speed-specific gravity relationship index corresponding to (temperature, pressure) may be stored, and these indices may be used. (B) In the above embodiment, the base gas is a gas mainly composed of methane (eg, natural gas), and the calorific value adjusting gas is a gas having a larger calorific value (eg, petroleum gas).
However, such a gas type does not matter. Therefore, in this case, it is a matter of course that a gas containing methane as a main component and a hydrocarbon gas having more carbon atoms than methane can be used. Further, as described above, it is possible to measure a product gas that has undergone calorific value adjustment and a so-called unheated gas that does not have calorific value adjustment.

[Brief description of the drawings]

FIG. 1 is a block diagram of a gas production facility equipped with a gas measurement device of the present application.

FIG. 2 is a diagram showing a basic structure of a measuring device.

FIG. 3 is a diagram showing a pressure-temperature-sound speed relationship index using a heat value as a parameter;

FIG. 4 is a diagram showing a sound speed-heat generation amount relationship index when a heat generation amount is derived from a sound speed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heat generation amount control device 2 Gas production equipment 15 Ultrasonic current meter 15a Ultrasonic transceiver 17a Storage means 17b Index generation means 18 Sound velocity derivation means 19 Sound velocity measurement means 20a Heat generation amount derivation means 20b Specific gravity derivation means 20c Wobbe index derivation means

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Koichi Sumida 4-1-2, Hirano-cho, Chuo-ku, Osaka-shi, Osaka Inside Osaka Gas Co., Ltd. (72) Kuniyoshi Okamoto Hirano-cho, Chuo-ku, Osaka-shi, Osaka F-term (reference) in Osaka Gas Co., Ltd. 1-2-2 chome 2G047 AA01 BA01 BC02 CA01 CB01 EA16 GG27

Claims (5)

[Claims] 1. A measuring pipe into which a gas to be measured is introduced and which flows through the inside of the measuring pipe in an axial direction, and a detecting unit of a pair of ultrasonic transceivers is provided in parallel with the flow of the gas to be measured in the measuring pipe. It is provided to face each other, and captures the propagation time of the ultrasonic wave propagating in the flow of the measurement target gas from one ultrasonic transceiver to the other ultrasonic transceiver in both directions, and performs the measurement from the pair of obtained propagation times. A sound speed deriving unit for obtaining a sound speed of the target gas, a calorific value deriving unit for obtaining a calorific value of the measurement target gas from a sound speed obtained by the sound speed deriving unit, a specific gravity deriving unit for obtaining a specific gravity of the measurement target gas, or A gas property measuring device comprising one or more means of Wobbe index deriving means for obtaining a Wobbe index of a gas to be measured. 2. A measuring pipe into which a gas to be measured is introduced and flowing in the pipe axis direction, and detection sections of a pair of ultrasonic transceivers are attached to both ends of the measuring pipe opposite to each other in the pipe axis direction. Provided facing each other, capture the propagation time of the ultrasonic wave propagating in the flow of the gas to be measured from one ultrasonic transceiver to the other ultrasonic transceiver in two directions, and obtain the measurement object from the pair of propagation times obtained. A sound speed deriving unit that obtains a sound speed of the gas; a calorific value deriving unit that obtains a calorific value of the gas to be measured from a sound speed obtained by the sound speed deriving device; a specific gravity deriving unit that obtains a specific gravity of the gas to be measured; or A gas property measuring device comprising one or more means of Wobbe index deriving means for obtaining a Wobbe index of a target gas. 3. A side pipe wall portion of the measurement tube, comprising an inlet for introducing the gas to be measured, and an outlet for guiding the gas to be measured flowing in the measurement tube in the axial direction. 2. The gas property measuring device according to 1. 4. A straight measuring tube into which a gas to be measured is introduced and which flows through the inside of the measuring tube. The detecting portions of a pair of ultrasonic transceivers are opposed to each other at opposite ends in the tube axis direction of the measuring tube. Using a measurement tube provided, the two-way capture of the propagation time of ultrasonic waves propagating in the flow of the gas to be measured from one ultrasonic transceiver to the other ultrasonic transceiver, and a pair of the obtained propagation A gas property measurement method for determining a sound speed of the measurement target gas from time, and determining a calorific value of the measurement target gas, a specific gravity of the measurement target gas, or a Wobbe index of the measurement target gas from the obtained sound speed. 5. The method according to claim 4, wherein the gas to be measured is a mixed gas containing methane as a main component and a hydrocarbon gas other than methane.