JPS58115359A - Calorimeter for gas - Google Patents

Abstract

PURPOSE:To ensure the stable and accurate measurement of calorific value, by holding a tubular heater which heats up a tubular calorimeter containing a powder grain oxide catalyst and a sensor detecting the temperature of the catalyst by a heat transmitting plate along with said calorimeter and therefore by carrying out an oxidation reaction under the fixed conditions. CONSTITUTION:A case 21 of a ''Pyrex '' tube, etc. contains a temperature sensor RS enclosed by the Al2O3 powder grains 22 and a temperature sensor SS enclosed by the glass wool 26 and a powder grain oxide catalyst 23. The gas G to be measured is supplied through a branch pipe 5a, and the waste gas is discharged through a branch pipe 5b. Such a calorimeter 3 is held in a heat insulating casing 1 along with a pair of heat transmitting plates 2a and 2b made of Al, etc. which are set in parallel. The plates 2a and 2b contain the depressed parts 8a and 8b to hold the meter 3 and a heater H of the meter 3. Then a gap 9 is formed at a place near the oxide catalyst SS of the meter 3, and a heat insulator 10 is put into the gap 9. Then the oxidation of the gas G is promoted by the heater H, and at the same time the dispersion of heat is prevented by the insulator 10. This enables the accurate detection of the sensor SS.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gas calorimeter mainly used for measuring the calorific value of fuel gas.

In recent years, there has been a demand for continuous and instantaneous measurement of the calorific value of gas for the purpose of controlling the refining process of city gas, etc., or for trading purposes. A method has been proposed in which a fixed sensor is provided and the amount of heat generated by the reaction between the gas and the catalyst is detected as a change in the resistance value of a platinum wire or the like.

However, in such a method, only a part of the gas pole comes into contact with the sensor, reducing the accuracy of #j, and when fixing the catalyst to a platinum wire, etc., it is difficult to coat the catalyst in the form of a slurry. It is sintered, and this process requires a high degree of skill.The mechanical strength is weak because ultra-fine platinum wires are used, and the solvent used to make the catalyst into a slurry remains, which causes The reliability of the sensor is degraded due to the adverse effects on the sensor.

The present invention has the purpose of fundamentally solving the drawbacks of the conventional method, and is directed to a tubular system comprising a powdery oxidation catalyst sealed in a gas passage and a temperature sensor that detects the temperature caused by the reaction of this oxidation catalyst. To provide an extremely effective gas calorimeter in which a calorimeter and a tubular heater are sandwiched between heat exchanger plates.

Hereinafter, the present invention will be explained in detail with reference to figures showing examples.

Figure 1 shows the entire configuration, and ω) is a front sectional view, and ω) is a side sectional view. A calorimeter 3, which will be described later, and a tubular cartridge-shaped heater H, which are sandwiched adjacently and parallel to each other by heat exchanger plates 2a and 2b, are housed therein, and a branch pipe to which gas G of the calorimeter 3 is supplied. 51, a branch pipe 5b1 through which exhaust gas RG is discharged, and each lead wire 6a to 6e.
7 and the like penetrate the outer casing 1 and are drawn out to the outside.

In addition, the heat exchanger plates 2a and 2b have four portions 8a and 8b that sandwich the calorimeter 3 and the heater 4 formed on the inner surfaces thereof facing each other. A gap 9 is formed in the vicinity of the calorimeter 3 where the oxidation catalyst is sealed, and a heat insulating material 10 such as wool is inserted into the gap 9.

Therefore, the calorimeter 3 is heated via the heat exchanger plates 2a and 2b by the heat generated by the heater H, and the oxidation reaction of the gas G with the oxidation catalyst is promoted, while the heat insulating material 10 in the air H9 makes the calorimeter 3 unnecessary. heat dissipation is prevented, and as explained later,
Temperature detection is performed accurately by a temperature sensor provided in the oxidation catalyst.

In addition, heat exchanger plates 2m, 2b T'S, screws 11a, 1
1b, both ends are fastened together, and the whole is assembled as one piece. These are enclosed in the heat-insulating outer casing 1, and the energization of the heater H is controlled by the control circuit described later. The inside of the housing 1 is maintained at a constant temperature.

Fig. 2 is a cross-sectional view of the calorimeter 3.A case 21 that forms a passage for gas G using a circular tube made of paper or biorex glass is provided with branch pipes 5m and 5b at both ends. , a temperature sensor R8 is installed in the case 21 on the side of the branch pipe 5a.
is inserted, and its surroundings are filled with alumina powder particles 22, and a temperature sensor SS is inserted into the case 21 on the side of the branch pipe 5b, and a powder-like oxidation catalyst 23 is inserted around it. is included.

Furthermore, electrodes 24m and 24b such as platinum wires are inserted into the oxidation catalyst 23 through the temperature sensor SS and facing each other, and lead wires 6a and 6 of the temperature sensors R8 and SS are respectively inserted.
c and the lead wires sb of the electrodes 24a and 24b; and the glass sealing part 25 melted and filled into the end of the case 1
a and 25b in an airtight manner and are drawn out to the outside.

In addition, 1,000-lumina powder particles 22 are filled between the oxidation catalyst 23 and the glass sealing part 25b, and glass wool 26 is filled in the void, branch pipe 5m, and Sb. , fixes each part and at the same time prevents leakage of the alumina powder particles 22.

Therefore, if the gas G diluted with air or oxygen-based combustion supporting gas is supplied from the branch pipe 5a and the calorimeter 3 is heated, the gas G passes through the temperature sensor R8 and reaches the oxidation catalyst 23. Here, an oxidation reaction is carried out to generate oxidation reaction heat, which is then discharged from the branch pipe 5b as exhaust gas RG. Therefore, by detecting the temperature due to the oxidation reaction with the temperature sensor SS, the amount of heat of the gas G can be determined.

Temperature sensor S
By correcting the detection power of S, the calorific value of gas G can be determined accurately.

Moreover, if a metal semiconductor oxide is used as the oxidation catalyst 23, the calorimeter 3 can be easily and easily calibrated by energizing the electrodes 24m and 24b.

That is, if a current is passed through the oxidation catalyst 23 by applying a voltage to the electrodes 24&, 24b, this will generate ohmic heat.
By comparing the detection power and the predetermined amount of heat generated,
Calibration is performed.

However, since there is a cooling effect during use due to the flow of gas G, during calibration, it is necessary to maintain the same conditions as during use by passing only the combustion supporting gas at the same flow rate as the mixed gas flowing during use.

Figure 3 is a circuit diagram of an attached circuit that displays the amount of heat detected by the temperature sensors SS and R8 and controls the energization of the heater H. After being stabilized by the diode ZD, the voltage is applied to each series circuit consisting of the temperature sensor 8S, R8- and the resistor R2+BS, and the temperature sensor 88. If the resistance value of R8 changes depending on the temperature, the terminal voltage of resistor Rt l R1 also changes, so this is
is applied to the inverting input and the non-inverting input of the differential amplifier Al through the . There is.

Note that the differential amplifier AI is provided with negative feedback by a resistor R6 in order to stabilize its operation.

In addition, the energization to the heater H is controlled according to the detected force of the temperature sensor R8, the heating state of the calorimeter 3 is kept constant, and the terminal voltage of the resistor R3 is set to a difference with strong negative feedback. A control circuit CT using a thyristor, etc., which is extracted via a dynamic amplifier A2 and performs periodic switching operations.
This supplies AC power to heater H.
The angle of flow of the current passing through is varied.

Therefore, the oxidation reaction of the gas G by the oxidation catalyst 23 is carried out under certain conditions, and the calorific value of the gas G can be measured stably and accurately.

Note that in order to check the deterioration status of the oxidation catalyst 23, it is sufficient to detect the combustible components remaining in the exhaust gas RG, so a known combustible gas sensor is connected to the branch pipe 5 and sealed in the Possible components may be detected or the exhaust gas RG may be inspected using a portable combustible gas detector.

In addition, if the oxidation catalyst 23 deteriorates, it is sufficient to reduce the supply amount of gas G per unit time so that all of the supplied gas G undergoes an oxidation reaction, making continuous use possible. .

In addition, temperature sensor 88. As R8, a tube made of alumina ceramic or the like with thin platinum wire sealed in it is suitable, and as the oxidation catalyst 23, Cu5p, Coo, M
nOs * Crs + Os + ZnO, F@mol,
VzOs, Mo5s+, etc. are used.

However, it is preferable to use a mixture of a plurality of combustible materials, since the characteristics of each component act complementary to each other, so that a more reliable oxidation reaction can be achieved with respect to various combustible components.

Note that it is effective to mix inert particles such as alumina powder into the oxidation catalyst 23 because this prevents mutual bonding due to fusion of the granular oxidation catalyst and prevents a decrease in surface area.

Therefore, the granular oxidation catalyst 23 with a large surface area and all of the gas G flowing through it are in complete contact, and all the gas G takes part in the oxidation reaction, so the calorific value of the gas G can be detected completely and accurately. In addition, the overall reliability is greatly improved because there is no need for exposed ultrafine platinum wires, and there is no need for coating or fixing catalysts.

In addition, the materials and shapes of the outer casing 1 and the heat exchanger plates 2a and 2b can be selected in various ways depending on the conditions, and depending on the situation, even if the void 9 and the heat insulating material 10 are omitted, the The result □ can be obtained.

The case 21 may be made of any material as long as it has heat resistance, airtightness 2, and chemical inertness, and its shape can be selected.
R can be modified in various ways, such as using a semiconductor such as a thermistor, and other substances exhibiting the same properties as the alumina powder particles 22 and glass wool 26. .

As is clear from the above description, according to the present invention, an accurate and highly reliable gas calorimeter can be obtained with a simple and easy-to-manufacture configuration, so that continuous and instantaneous calorific value measurement of various combustible gases can be achieved. This makes it possible to achieve remarkable effects in refining process management and trading of fuel gas, etc.

[Brief explanation of the drawing]

The figures show an embodiment of the present invention, and FIG. 1 (4) is a front sectional view of the entire configuration, FIG. 1 (B) is a similar side sectional view, FIG. 2 is a sectional view of the calorimeter, and FIG. FIG. 3 is a circuit diagram of an attached circuit. 1...outer casing, 2m, 2b ^...heat exchanger plate,
3...IIF Roly meter, 21...Case, 2
3... Oxidation catalyst, 24a, 24b... Electrode, l
(...Fist/heater, 88, SR...Temperature sensor, G...Gas. Patent applicant: Yamatake)・Newel Co., Ltd. agent Masaki Yamakawa (and 1 other person) G RG Figure 2 G
RG figure 3

Claims (2)

[Claims] (1) A tubular calorimeter equipped with a powdery oxidation catalyst sealed in a gas passage and a temperature sensor that detects the temperature caused by the reaction of the oxidation catalyst; a tubular heater that heats the calorimeter; A gas calorimeter comprising a calorimeter and a heater placed adjacent to each other and a heat transfer plate sandwiching the calorimeter and heater in parallel. (2) A gas calorimeter according to claim 1, characterized in that a heat exchanger plate is used in which nine gaps for preventing heat radiation are provided in the holding portion of the calorimeter and in the vicinity of the oxidation catalyst.