JP2686298B2 - Gas temperature measuring device and gas analyzer using the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a gas temperature measuring device and a gas analyzer using the gas temperature measuring device, and in particular, to accurately measure the gas temperature even when the gas composition changes. The present invention relates to a gas temperature measuring device for measuring and a gas analyzer for calculating a gas composition backward from a sound velocity constant determined by the gas temperature measuring device.

[Conventional technology]

There are many temperature measurement methods, but from the usage format,
There are two types, a contact type and a non-contact type.
The contact type, as represented by a thermocouple, can measure the temperature at the insertion point with extremely high accuracy. On the other hand, a non-contact type such as a radiation thermometer is industrially highly used because it can measure a high-temperature object from a long distance, though the accuracy is slightly lowered.

Many of the non-contact types use light, but recently, a method using sound waves has been attracting attention. FIG.
A typical example of using an acoustic thermometer to measure the temperature of a boiler furnace is shown below.

In FIG. 10, a burner 60 is installed in the furnace 61, and this high-temperature combustion gas (about 1300K) passes through the heat transfer tube 50 to generate steam, and is then cooled to a low-temperature gas (about 600K). And goes out to the chimney. At the furnace outlet, a transmitter 4 and a receiver 5 of sound waves for measuring gas temperature are provided.

The procedure for measuring the temperature is shown below. Sound wave transit time measuring device
The weak pulse electric signal emitted from 11 is amplified by the amplifier 9 and reaches the transmitter 4. Then, it is converted into pulsed sound waves, propagates through the high temperature gas 2 in the furnace 61, and reaches the receiver 5. The sound wave that has arrived is converted into a weak pulse electric signal again, is amplified by the amplifier 10, and returns to the propagation time measuring device 11. The propagation time measuring device 11 measures the propagation time ι (sec) from when the pulsed electric signal is emitted until it returns.

The sound wave propagation time i and the gas temperature T (K) have the following relationship.

Here, L is a distance (m) between the transmitter and the receiver, and a is a sound velocity constant determined by the gas composition.

In the equation (1), since the distance L is a known value that is structurally determined, the gas temperature T can be obtained by measuring the propagation time ι of the sound wave. This calculation is performed by the gas temperature calculator 12 and displayed on the display 41.

In FIG. 10, 1 is a duct, 2 is a high temperature gas,
3 shows a low temperature gas.

[Problems to be solved by the invention]

In the equation (1), the sound velocity constant a is constant as long as the gas composition does not change. However, the exhaust gas composition changes in the boiler shown in FIG. For example, at the time of start-up, the atmosphere is flowing in the furnace, and the main composition is about 76% nitrogen, 20% oxygen, and 3% steam. On the other hand, the gas composition during full load operation is about 63% nitrogen, 2% oxygen, 11% carbon dioxide, and 23% steam.

FIG. 11 is a graph showing the relationship between changes in gas composition and changes in sound velocity constant.

In FIG. 11, the horizontal axis represents the exhaust gas oxygen concentration corresponding to the boiler load, and the vertical axis represents the rate of change based on the sound velocity constant of the atmosphere. From FIG. 11, it can be seen that the sound velocity constant changes by about 3%. Since the temperature at full load is about 1300K, a measurement error of 40 ° C will occur.

This value is a value that cannot be ignored when operating the boiler. It should be noted that when the load is changed frequently, it does not change so much, but the sound velocity constant also changes by about 2% and cannot be ignored.

In order to correct this, it is necessary to constantly measure the sound velocity constant, but this is almost impossible because the measurement is performed in a high temperature field and the device configuration becomes large. Therefore, at present, no correction is performed.

As described above, since the conventional acoustic thermometer does not correct the sound velocity constant due to the change in gas composition, there is a problem that the measurement error is large.

A first object of the present invention is, even when the gas composition is changed between the time of start-up and the time of load operation, such as a boiler,
An object of the present invention is to provide a gas temperature measuring device capable of accurately measuring the gas temperature on the high temperature side.

A second object of the present invention is to provide a gas temperature measuring device capable of measuring a gas temperature distribution in a cross section of a gas flow channel (a cross section in a direction orthogonal to the gas flow).

A third object of the present invention is to provide a gas temperature measuring device in which a transmitter and a receiver for determining a sound velocity constant and a gas thermometer can be compactly integrated and which can be easily attached or detached for inspection. It is in.

A fourth object of the present invention is to provide a gas temperature measuring device capable of measuring gas temperature more accurately without the influence of vibrations on the transmitter and receiver.

A fifth object of the present invention is to provide a gas composition analyzer capable of back-calculating the gas composition from the sound velocity constant measured by the gas temperature measuring device.

[Means for solving the problem]

In the gas temperature measuring device equipped with an acoustic thermometer, the first object is to provide at least a sonic velocity constant determination on the low temperature gas side of the gas flow path, separately from the gas temperature measurement transmitter and receiver. A pair of transmitter and receiver and a gas thermometer capable of directly measuring the gas temperature are provided, and the transmitter and receiver for determining the sound velocity constant are connected to the propagation time measuring device, and the propagation time measuring device and the gas measuring device are connected. The thermometer and the sound wave propagation time and transmission,
This is achieved by determining the sound velocity constant from the distance between the receivers and the gas temperature, and connecting the gas temperature calculator that calculates the gas temperature of the non-measurement part based on this sound velocity constant.

The second purpose is to send a sound wave for measuring the gas temperature, to send a sound wave over substantially the entire cross section of the gas flow path,
This is achieved by arranging it to be acceptable.

The third purpose is to send the sound velocity constant for determination.
This can be achieved by incorporating the receiver and the gas thermometer in a single cylinder.

Further, the fourth object is achieved by attaching the transmitter and receiver to a member to be attached via a vibration isolator.

And the said 5th objective uses the said gas temperature measuring device which concerns on this invention, A gas temperature calculator in this gas temperature measuring device WHEREIN: A gas composition is calculated back from the sound velocity constant calculated by this gas temperature calculating device. This is achieved by connecting the gas composition calculator to

[Action]

In the gas temperature measuring device of the present invention, the gas temperature is directly measured by the gas thermometer provided on the low temperature gas side of the gas flow path, and the measured gas temperature T is sent to the gas temperature calculator. Similarly, a sound wave is sent from the propagation time measuring device, which is also provided on the low temperature gas side, for determining the sound velocity constant → the transmitter → the receiver, and the sound wave is returned to the receiver → the propagation time measuring device. The propagation time is measured, and the measured sound wave propagation time ι is sent to the gas temperature calculator. The distance L between the transmitter and the receiver for determining the sound velocity constant is a known value determined by the mounting position, and is measured in advance and inserted into the gas temperature calculator.

In the gas temperature calculator, the gas temperature T, the sound wave propagation time ι, and the distance L between the transmitter and the receiver for determining the sound velocity constant are substituted into the equation (1) to obtain the current sound velocity constant a. To calculate. Then, the gas temperature calculator takes in the propagation time ι of the sound wave of the measured part from the gas temperature measuring transmitter, receiver and propagation time measuring device, and the distance L between the gas temperature measuring transmitter and receiver is The gas temperature T of the measured portion is calculated by accepting the value as a known value, and substituting the calculated sound velocity constant a and the equation (1).

Therefore, the gas temperature measuring device of the present invention can accurately measure the gas temperature on the high temperature side even when the gas composition changes between startup and load operation, such as in a boiler.

Further, in the gas temperature measuring device of the present invention, since the gas temperature measuring transmitter and receiver are installed so as to transmit and receive sound waves over substantially the entire cross section of the gas channel, the gas channel It is possible to measure and know the gas temperature distribution in the cross section of.

Further, in the gas temperature measuring device of the present invention, since the sending and receiving device for determining the sound velocity constant and the gas thermometer are incorporated in a single cylinder, the sending and receiving device and the gas thermometer are compact. It can be easily assembled and installed, and can be easily removed and inspected.

Furthermore, in the gas temperature measuring device of the present invention, since the transmitter and the receiver are attached to the member to be attached such as the waveguide via the vibration-proof material, it is not affected by the vibration of the portion to be measured.
The speed of sound can be measured accurately, and as a result, the gas temperature can be measured even more accurately.

Then, in the gas analyzer of the present invention, the sound velocity constant a calculated by the gas temperature calculator of the gas temperature measuring device is sent to the gas composition calculator. Since this sonic velocity constant a is a value determined by the gas composition, the gas composition calculator back-calculates the gas composition based on the sonic velocity constant a and outputs it. Therefore, in the gas analyzer of the present invention, the current gas composition can be known based on the sound velocity constant a sent from the gas temperature calculator of the gas temperature measuring device.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a system diagram showing an embodiment of the gas temperature measuring device of the present invention.

In the gas temperature measuring apparatus of the embodiment shown in FIG. 1, an acoustic thermometer for measuring gas temperature provided on the high temperature gas 2 side of the duct 1 and an acoustic thermometer for sound velocity determination provided on the low temperature gas 3 side. A gas thermometer 8 for directly measuring a gas thermometer and a gas temperature, and a gas temperature calculator 12 are provided.

A heat transfer tube 50 is installed in the duct 1, and the inside of the duct 1 is divided into a high temperature gas 2 side and a low temperature gas 3 side with the heat transfer tube 50 as a boundary.

The acoustic thermometer on the high temperature gas 2 side is a propagation time measuring device.
11, a transmitter 4 attached to the duct 1 via a waveguide 15, and a transmitter 4 associated with the transmitter 4 and connected to the duct 1.
And a receiver 5 mounted via 15. The transmitter 4 is connected to the propagation time measuring device 11 via a cable 14 and an amplifier 10. The receiver 5 is connected to the same propagation time measuring device 11 via a cable 14 and an amplifier 9. The propagation time measuring device 11 is connected to the gas temperature calculator 12.

On the other hand, the acoustic thermometer on the side of the low-temperature gas 3 includes a propagation time measuring device 11 ', a transmitter 6 attached to the duct 1 via a waveguide 15, and a duct 6 corresponding to the transmitter 6. 1
And a receiver 7 mounted via a waveguide 15. The transmitter 6 is connected to the propagation time measuring device 11 'through a cable 14 and an amplifier 10. The receiver 7 is connected to the same transit time measuring device 11 'via a cable 14 and an amplifier 9. The transmitter 6 and the receiver 7 are installed on the streamline of gas passing through the installation locations of the transmitter 4 and the receiver 5 for measuring the gas temperature.
The propagation time measuring device 11 ′ is also connected to the gas temperature calculator 12. The gas thermometer 8 is mounted at a position as close as possible to the receiver 7. This gas thermometer 8
For this, a thermocouple is usually used. This gas thermometer 8 is also connected to the gas temperature calculator 12 through a cable 14.

In the gas temperature calculator 12, the propagation time ι of the sound wave on the high temperature gas 2 side is sent from the propagation time measuring device 11 and the propagation time ι of the sound wave on the low temperature gas 3 side is sent from the propagation time measuring device 11 '. , Pre-measured transmitter and receiver 4, 5
The distance L between them and the distance L between the transmitter and receiver 6 and 7 are transmitted.

The gas temperature measuring device of the above embodiment operates as follows to measure the gas temperature.

That is, the weak pulse electric signal emitted from the propagation time measuring device 11 ′ of the acoustic thermometer on the low temperature gas 3 side is amplified by the amplifier 10 and reaches the transmitter 6. A pulsed sound wave is emitted from the transmitter 6 and reaches the receiver 7 installed at the opposite position. This sound wave is converted into a weak pulse electric signal, is amplified by the amplifier 9, and is propagated by the propagation time measuring device 1
Return to 1 '. The propagation time measuring device 11 ′ measures the propagation time ι of the sound wave and sends the measured value to the gas temperature calculator 12.

On the other hand, the gas temperature T on the side of the low temperature gas 3 is measured by the gas thermometer 8 attached at substantially the same position as the receiver 7,
This measured value is also sent to the gas temperature calculator 12.

Since the distance L between the sending and receiving devices 6 and 7 on the low temperature gas 3 side is known in advance, it is sent to the gas temperature calculator 12.

Here, the gas temperature calculator 12 determines the propagation time of the sound wave ι.
And the gas temperature T on the low-temperature gas 3 side and the distance L between the transmitter and receiver 6 and 7 are substituted into the above equation (1) to calculate the sound velocity constant a at the present time.

Similarly, on the high temperature gas 2 side, the propagation time measuring unit 11 of the acoustic thermometer measures the propagation time ι of the sound wave between the transmitter 4 and the receiver 5, and sends the measured value to the gas temperature calculator 12.

The distance L between the transmitter and receiver 4 and 5 on the high temperature gas 2 side is
Since it is known by measurement in advance, it is sent to the gas temperature calculator 12. The sound velocity constant a at present is already calculated as described above.

Therefore, in the gas temperature calculator 12, the propagation time of the speed of sound ι
Then, the distance L between the transmitter / receivers 4 and 5 and the sound velocity constant a are substituted into the equation (1) to calculate and output the gas temperature T on the high temperature gas 2 side.

As described above, in this embodiment, the current sonic velocity constant a is calculated, and the sonic velocity constant a is used to measure the gas temperature on the high-temperature gas 2 side. Even if the gas composition changes during operation, the gas temperature at that time can be accurately measured.

FIG. 2 is a cross-sectional view of the duct on the low temperature gas side when the gas temperature measuring device of the present invention is applied to a large duct.

In the embodiment shown in FIG. 2, two pairs of a sound wave transmitter 6 for determining the sound velocity constant, a receiver 7 and a gas thermometer 8 are installed. Also, two pairs of transmitters and receivers are installed on the side of the high temperature gas 2 which is the part to be measured upstream so as to correspond to the transmitter 6 and the receiver 7, but they are omitted in FIG. ing.

In a large-sized boiler, the gas temperature on the left and right is unbalanced in the cross section of the duct, but according to the embodiment shown in FIG. 2, the gas temperature can be measured more accurately.

FIG. 3 shows another embodiment of the gas temperature measuring device of the present invention, and is a transverse cross-sectional view of a position where a transmitter and receiver of sound waves on the high temperature gas side are attached.

In the embodiment shown in FIG. 3, the hot gas 2 in the duct 1 is
In the side cross section (cross section in the direction orthogonal to the gas flow),
A receiver 20 is installed above and below and to the left and right, and a sound wave propagation path 21 is configured to extend over almost the entire area within the cross section of the duct 1. As a result, it is possible to measure and know the gas temperature distribution in the cross section of the duct 1.

FIG. 4 shows another embodiment of the gas temperature measuring device of the present invention, and is a vertical cross-sectional view on the low temperature gas side, and FIG. 5 is an enlarged vertical cross-sectional view of the essential part of this embodiment.

In the embodiment shown in FIGS. 4 and 5, the transmitter 6 for determining the sound velocity constant, the receiver 7, and the gas thermometer 8 are incorporated in the calibration cylinder 22 which is a single cylinder. The calibration tube
As shown in FIG. 5, the hole 22 is provided with a large number of holes 23, through which the gas flows in the calibration cylinder 22. The calibration tube 22, as shown in FIG.
It is attached to the low temperature gas 3 side of the duct 1. As shown in FIG. 5, the transmitter 6 is provided on the bottom side of the calibration tube 22, the receiver 7 is provided above the calibration tube 22 so as to correspond to the transmitter 6, and the gas thermometer 8 is It is provided at a position close to the receiver 7.

In this embodiment, since the transmitter and receivers 6 and 7 for determining the sound velocity constant and the gas thermometer 8 are incorporated in the calibration cylinder 22, these members can be compactly assembled and easily installed. Can be used.

FIG. 6 is a vertical cross-sectional view of the essential parts showing a different embodiment of the gas temperature measuring device of the present invention.

In the embodiment shown in FIG. 6, an elbow type waveguide 24
In addition, a transmitter / receiver 20 for determining the sound velocity constant and a gas thermometer 8 are incorporated. The waveguide 24 is removably attached to the low temperature gas 3 side of the duct 1 with a set bolt 25.

Therefore, according to this embodiment, the transmitter and receiver 20 for determining the sound velocity constant and the gas thermometer 8 can be compactly assembled, and can be easily attached and used by the set bolt 25, and can be easily used for inspection and maintenance. It can be removed.

FIG. 7 is a vertical sectional view showing still another embodiment of the gas temperature measuring device of the present invention.

In the embodiment shown in FIG. 7, a sound wave transmitter / receiver 20 is mounted in a waveguide 15 by being wrapped in a damper 30 which is a vibration isolator.

According to this embodiment, the sound wave can be sent and received without being affected by the vibration of the sender and receiver 20, and the propagation time of the sound wave can be measured more accurately.

Next, FIG. 8 is a system diagram showing an embodiment of the gas analyzer of the present invention.

In the gas analyzer shown in FIG. 8, the gas temperature measuring device shown in FIGS. 1 to 7 is used, and the gas composition calculator 40 connected to the gas temperature calculator 12 of the gas temperature measuring device is used.
And a display 41 connected to this gas composition calculator 40.
And

The gas composition calculator 40 determines on the low temperature gas 3 side,
In addition, the sonic velocity constant a calculated by the gas temperature calculator 12 is sent. This sound velocity constant a is determined by the composition of the gas. Therefore, the gas composition calculator 40 back-calculates the composition of the gas based on the sound velocity constant a and outputs the calculated value to the display 41. The display 41 is
In this embodiment, the gas temperature information 42 calculated by the gas temperature calculator 12 and the gas composition information calculated by the gas composition calculator 40
43 and are displayed.

When the composition of fuel is clear like a boiler, the gas composition is calculated by the gas composition calculator 40 based on the sound velocity constant a obtained on the low temperature gas 3 side and is displayed on the display 41 at present. You can know the gas composition of.

Next, FIG. 9 is a system diagram showing an example of use of the gas temperature measuring device of the present invention. In the usage example shown in FIG. 9, the gas temperature measuring device of the present invention is applied to a boiler having a burner 60 and a furnace 61. In FIG. 9, the same members as those of the gas temperature measuring device described above are designated by the same reference numerals, and further description will be omitted.

〔The invention's effect〕

According to the invention of claim (1) of the present invention, in the gas temperature measuring device equipped with the acoustic thermometer, the transmitter and receiver for measuring the previous gas temperature are provided on the low temperature gas side of the gas flow path. Separately, at least a pair of transmitter and receiver for determining the sound velocity constant,
Provided with a gas thermometer capable of directly measuring the gas temperature, the transmitter for determining the sound velocity constant, the receiver is connected to the propagation time measuring device, the propagation time measuring device and the gas thermometer,
Since it is connected to a gas temperature calculator that determines the sound velocity constant from the sound wave propagation time and transmission, the distance between the receiver and the gas temperature, and calculates the gas temperature of the non-measurement part based on this sound velocity constant,
Gas temperature T directly measured by a gas thermometer, sound wave transmission, sound wave propagation time ι on the low temperature gas side measured by a receiver and a propagation time measuring device, and known distances between the transmitter and receiver tubes Substituting L and L into the equation (1) with a gas temperature calculator,
The sound velocity constant a in the present situation is determined, and this sound velocity constant a is
The propagation time ι of the sound wave of the measured part measured by the sending and receiving device and the propagation time measuring device for gas temperature measurement, and the known sending and receiving pipe distance L are again measured by the gas temperature calculator. By substituting it in the equation (1), like a boiler,
Even if the gas composition changes between startup and load operation, there is an effect that the gas temperature on the high temperature side as the measured portion can be accurately measured.

Further, according to the invention of claim (2) of the present invention, the transmitter and receiver for measuring the gas temperature are installed so as to be able to transmit and receive sound waves over substantially the entire cross section of the gas flow path. Therefore, there is an effect that can be known by measuring the gas temperature distribution in the cross section of the gas flow path.

Further, according to the invention of claim (3) of the present invention,
Since the transmitter and receiver for determining the sound velocity constant and the gas thermometer are incorporated in a single cylinder, the transmitter and receiver and the gas thermometer can be compactly assembled and easily installed. There is an effect that it can be easily removed and inspected.

Further, according to the invention as set forth in claim (4) of the present invention, the transmitter and the receiver are mounted on the member to be mounted such as the waveguide through the vibration isolator, so that they are affected by the vibration. Without
The sound velocity can be measured accurately, and as a result, the gas temperature of the measured portion can be measured more accurately.

According to the invention of claim (5) of the present invention,
The gas temperature calculator in the gas temperature measuring device is connected to a gas composition calculator that calculates the gas composition backward from the sonic constant calculated by this gas temperature calculator, and the gas temperature calculator of the gas temperature measuring device calculates the gas composition. Since the sound velocity constant a is sent to the gas composition calculator, and the gas composition calculator calculates the gas composition backward based on the sound velocity constant a and outputs it.
Based on the sound velocity constant a sent from the gas temperature calculator of the gas temperature measuring device, there is an effect that the current gas composition can be known.

[Brief description of the drawings]

FIG. 1 is a system diagram showing one embodiment of the gas temperature measuring device of the present invention, and FIG. 2 is a cross-sectional view of the duct on the low temperature gas side when the gas temperature measuring device of the present invention is applied to a large duct. ,
FIG. 3 shows another embodiment of the gas temperature measuring device of the present invention. A cross-sectional view of the position at which a sound wave transmitting / receiving device is attached on the high temperature gas side, and FIG. FIG. 6 shows another embodiment of the temperature measuring device, and FIG. 5 is a longitudinal sectional view of the low temperature gas side, FIG. 5 is an enlarged longitudinal sectional view of the essential part of this embodiment, and FIG. FIG. 7 is a vertical sectional view of a main part showing a different embodiment, FIG. 7 is a vertical sectional view showing a further different embodiment of the gas temperature measuring device of the present invention, and FIG. 8 is an embodiment of the gas analyzer of the present invention. System diagram, FIG. 9 is a system diagram showing a use example in which the gas temperature measuring device of the present invention is applied to a boiler, and FIG. 10 is a system diagram of a use example in which a conventional acoustic thermometer is applied to a boiler, 11 The figure is a diagram showing the relationship between the gas composition and the sound velocity constant in the boiler. 1 ... Duct which is a gas flow path, 2 ... High temperature gas, 3 ...
Low temperature gas, 4, 5 ... Transmitting and receiving sound waves on the high temperature gas side,
6, 7 …… Sound wave transmitter / receiver for low temperature gas side, 8 …… Gas thermometer, 11 …… Sound wave time measuring device for high temperature gas side, 1
1 '... Sound wave propagation time measuring device on low temperature gas side, 12 ... Gas temperature calculator, 14 ... Cable, 15 ... Waveguide, 20 ...
Sound wave transmitter / receiver, 21 ... Sound wave propagation path, 22 ... Calibration tube, 24 ... Elbow type waveguide, 30 ... Damper which is a vibration isolator, 40 ... Gas composition calculator, 41 ...... Display, 50 ...
… A heat transfer tube installed in the duct.

Claims (5)

(57) [Claims] 1. A gas flow path is provided with at least a pair of sound wave sending and receiving devices for measuring gas temperature, and the sound velocity between the sending and receiving devices is measured to flow between the sending and receiving devices. In a gas temperature measuring device equipped with an acoustic thermometer for calculating the temperature of gas, on the low temperature gas side of the gas flow path, apart from the transmitter and receiver for measuring the gas temperature, at least one pair for determining the sonic velocity constant. Is provided with a receiver and a gas thermometer capable of directly measuring the gas temperature, and the transmitter and receiver for determining the sound velocity constant are connected to the propagation time measuring device, and the propagation time measuring device and the gas temperature measuring device. And the transmission time of the sound wave,
A gas temperature measuring device, characterized in that a sonic constant is determined from a distance between receivers and a gas temperature, and the sonic constant is connected to a gas temperature calculator for calculating a gas temperature of a non-measurement portion based on the sonic constant. 2. The gas temperature according to claim 1, wherein the gas temperature measuring transmitter and receiver are arranged so as to be capable of transmitting and receiving sound waves over substantially the entire cross section of the gas flow path. Measuring device. 3. The gas temperature measuring device according to claim 1, wherein the transmitter / receiver for determining the sound wave constant and the gas thermometer are incorporated in a single cylindrical body. 4. The gas temperature measuring device according to claim 1, wherein the transmitter and receiver are attached to a member to be attached via a vibration isolator. 5. A gas composition for a gas temperature calculator in the gas temperature measuring device according to claim 1, wherein the gas composition is calculated back from the sound velocity constant calculated by the gas temperature calculator. A gas analyzer which is connected with a calculator.