JP6166149B2 - Calorimeter and calorie measuring method - Google Patents

Description

  The present invention relates to a gas calorimetric technique, and more particularly to a small calorimeter or the like that can measure the calorific value of a gas continuously and with a relatively simple structure.

  Conventionally, various calorimeters are used for the purpose of measuring the amount of heat such as city gas.

  Such conventional calorimeters use the Junkers flow gas calorimeter method, which is a legal measurement method, a gas chromatograph method, a rapid response calorimeter (described in Patent Document 1 below), a gas density calorimeter, and the like. And a thermal conductivity calorimeter (described in Patent Document 2 below).

  Patent Document 3 below describes a measurement method using an oxidation catalyst. In this method, gas is passed through a heated catalyst to cause catalytic combustion, and the amount of heat is obtained from a temperature change or the like.

Japanese Patent No. 4844377 Japanese Patent No. 4890874 Japanese National Patent Publication No. 11-506537

  However, the above-mentioned Junkers-type flowing water gas calorimeter method and gas chromatograph method have a problem that continuous measurement is impossible.

  Further, the rapid response calorimeter has a problem that the measured value drifts when used for a long time, and has a drawback that the apparatus is large.

  In addition, the above-mentioned gas density calorimeter and thermal conductivity calorimeter have the problem that the density and thermal conductivity cannot be distinguished between the air component and the combustible gas component, so the accuracy deteriorates when the air component is mixed. There is.

  Further, in the method and apparatus described in Patent Document 3, the measurement method and the apparatus therefor are comparatively used, such as a procedure in which a reference gas and a sample gas are alternately flowed, and a chamber for each gas is provided. There is a problem of being complicated.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a gas calorimeter that can measure the calorific value of a gas continuously and accurately, and has a relatively simple structure and a small calorimeter. It is.

  In order to achieve the above object, according to one aspect of the present invention, there is provided a calorimeter that measures the calorific value of a continuously flowing gas, a first oxidation catalyst into which the gas is introduced, and a gas that surrounds the gas. A second oxidation catalyst that is not introduced into the circuit, a bridge circuit that includes resistors provided in the first oxidation catalyst and the second oxidation catalyst, respectively, and a current that detects an inter-bridge current of the bridge circuit And when the voltage is applied to the bridge circuit, the first oxidation catalyst and the second oxidation catalyst are heated by the resistor, and the gas is introduced around the first oxidation catalyst, the current And a calculation unit that obtains the amount of heat of the gas based on the current value detected by the meter.

  Furthermore, in the above invention, a preferable aspect is characterized in that the bridge circuit is a Wheatstone bridge circuit.

  Furthermore, in the above-mentioned invention, a preferable aspect further includes a gas introduction pipe for guiding the gas to the periphery of the first oxidation catalyst.

  Furthermore, in the above-mentioned invention, one preferable aspect further includes an air pipe for guiding air to the first oxidation catalyst.

  Moreover, in the above invention, one aspect is characterized in that a tip of the air pipe opens in the vicinity of the first oxidation catalyst.

  In the above invention, another aspect is characterized in that a tip of the air pipe opens inside the gas introduction pipe.

  Furthermore, in the above invention, one aspect is characterized in that the first oxidation catalyst is formed of a porous body, and the gas introduction pipe extends to the vicinity of the resistor of the first oxidation catalyst. To do.

  In order to achieve the above object, according to another aspect of the present invention, there is provided a calorimetric method for measuring a calorific value of a continuously flowing gas, wherein a first oxidation catalyst into which the gas is introduced to the surroundings, and the gas A bridge circuit including a second oxidation catalyst that is not introduced to the surroundings, resistors provided in the first oxidation catalyst and the second oxidation catalyst, respectively, as elements of the electric circuit, and an inter-bridge current of the bridge circuit is detected. An ammeter, applying a voltage to the bridge circuit, heating the first oxidation catalyst and the second oxidation catalyst by the resistor, introducing the gas around the first oxidation catalyst, The amount of heat of the gas is obtained based on the current value detected by the ammeter.

  Further objects and features of the present invention will become apparent from the embodiments of the invention described below.

It is a block diagram which concerns on the example of embodiment of the calorimeter to which this invention is applied. 2 is a more specific configuration diagram of the calorimeter 1. FIG. It is the figure which showed the deformation | transformation form.

  Embodiments of the present invention will be described below with reference to the drawings. However, such an embodiment does not limit the technical scope of the present invention. In the drawings, the same or similar elements are denoted by the same reference numerals or reference symbols.

  FIG. 1 is a configuration diagram according to an embodiment of a calorimeter to which the present invention is applied. A calorimeter 1 shown in FIG. 1 is a calorimeter to which the present invention is applied. Although details will be described later, the temperature of a detection unit 3 that introduces a gas to be measured and performs catalytic combustion and a temperature of a reference unit 4 that does not introduce the gas Measure the heat value of the gas based on the difference. In addition, a bridge circuit to which a voltage is applied is used as a heating device for catalytic combustion, and the temperature difference is obtained based on a current value detected between the bridges. By using the calorimeter 1, the calorific value of the gas can be continuously measured with a relatively simple device.

  FIG. 1 shows a general functional configuration of the calorimeter 1. In this embodiment, the calorimeter 1 is installed in a city gas factory or house supply pipe (gas pipe in the figure) and continuously (as needed) measures the amount of heat of the gas flowing through the supply pipe. Assumes that.

  The gas flow rate measuring unit 2 is a part that measures the amount of gas introduced into the calorimeter 1 from the gas pipe. The detection unit 3 is a part where the above-described catalytic combustion is performed by the introduced gas, and the reference unit 4 is a part which measures a value for performing zero point correction for heat quantity measurement without introducing the gas. Yes, it is a part that is referred to in order to measure only the amount of heat by gas. The heating circuit unit 5 is an electric circuit (the bridge circuit) for heating the oxidation catalyst provided in the detection unit 3 and the reference unit 4. In addition, the specific structure (structure) of the detection part 3, the reference part 4, and the heating circuit part 5 is mentioned later.

  The calculation unit 6 is a part for obtaining the heat quantity of the gas from the measurement values detected by the gas flow rate measurement unit 2 and the heating circuit unit 5. A specific method will be described later. The calculation unit 6 can be configured by a so-called microcomputer or the like, and includes a CPU, a RAM, a ROM, an ASIC, a display device, an input device, and the like (not shown). Further, a communication interface for communicating with an external device may be provided.

  FIG. 2 is a more specific configuration diagram of the calorimeter 1. As shown in FIG. 2, the gas flow rate measuring unit 2 is provided with a flow meter 21, and the flow rate of gas introduced into the calorimeter 1 from the gas pipe (the supply pipe) (for example, V liter / second) Measure continuously during measurement. The measured flow rate is transmitted to the calculation unit 6.

  The detection unit 3 is provided with a detection unit catalyst 35 (first oxidation catalyst) including a detection unit heating element 36 (resistor) inside. The detection unit catalyst 35 is, for example, an oxidation catalyst hardened in a spherical shape, and a Pt-based catalyst, a Pd-based catalyst, or the like can be used. The detection unit heating element 36 is an electric resistance (first resistor) and constitutes a part of an electric circuit (for example, a Wheatstone bridge circuit) of the heating circuit unit 5 described later. By applying electricity to the detection unit heating element 36, the detection unit catalyst 35 is heated.

  The gas introduction pipe 31 is a pipe for introducing the gas measured by the flow meter 21 to the vicinity (surrounding) of the detection unit catalyst 35. It is preferable that the tip of the gas introduction pipe 31 is positioned so that the gas is blown onto the detection unit catalyst 35.

  The air pipe 32 (air pipe) is a pipe that blows in air for supplying oxygen for gas combustion. Like the gas introduction pipe 31, the air pipe 32 is provided so that its tip is located in the vicinity of the detection unit catalyst 35. It has been. Accordingly, air is blown around the detection unit catalyst 35. Although not shown, a blower or the like can be provided upstream of the air pipe 32.

  Next, as shown in FIG. 2, the reference portion 4 is provided with a reference portion catalyst 45 (second oxidation catalyst) including a reference portion heating element 46 (resistor) inside. The reference part heating element 46 and the reference part catalyst 45 have the same specifications as the detection part heating element 36 and the detection part catalyst 35.

  Next, the heating circuit unit 5 is provided with an electric circuit for causing a current to flow through the detection unit heating element 36 and the reference unit heating element 46 to generate heat. Here, as an example, the electric circuit constitutes a Wheatstone bridge circuit. As shown in FIG. 2, the electric circuit includes a bridge circuit to which a predetermined voltage is applied by a power source 51, and a detection unit as a first resistor connected in series is provided on one of the paths. A heating element 36 and a reference portion heating element 46 as a second resistor are provided, and a third resistor 53 and a fourth resistor 54 are connected in series to the other path connected in parallel with the heating element 36. .

  The resistance values of these resistors are the values between the bridges (the output terminals between the detection unit heating element 36 and the reference unit heating element 46) when no gas is introduced into the detection unit 3, that is, when the gas is not combusted. And between the output terminals between the third resistor and the fourth resistor). An ammeter 52 for measuring (detecting) the current flowing between the bridges is provided between the bridges, and the current value measured here is transmitted to the calculation unit 6.

  Next, a method for measuring the amount of heat in the calorimeter 1 having such a configuration will be described. First, the power supply 51 of the heating circuit unit 5 is turned on, and the detection unit catalyst 35 is heated to a temperature range in which the detection unit catalyst 35 can be completely combusted by heat generation from the detection unit heating element 36, for example, 400 ° C. or more. Thereafter, a substantially constant amount of gas (V liter / second is approximately constant) is continuously introduced from the gas pipe into the vicinity of the detection unit catalyst 35 via the flow meter 21 and the gas introduction pipe 31. The introduced gas is catalytically combusted by the heated detector catalyst 35 (oxidation catalyst) and air introduced from the air pipe 32, and is completely combusted.

  The temperature of the detection part catalyst 35 rises by the said combustion. Thereafter, approximately the same amount of gas is continuously introduced and the combustion is continued. When a certain amount of time has elapsed after the start of combustion, the state of the detection unit catalyst 35 becomes stable and the temperature becomes substantially constant. In this steady state, the heat input to the detection unit catalyst 35 and the heat release from the detection unit catalyst 35 are balanced (heat input = heat release).

  On the other hand, in the reference portion 4, after the power is turned on, the reference portion catalyst 45 is heated by the heat generated from the reference portion heating element 46, and the temperature of the reference portion catalyst 45 rises. Since no gas is introduced into the reference portion 4, there is no temperature rise due to combustion, and the temperature of the reference portion catalyst 45 becomes substantially constant when a certain time elapses after the power is turned on. In this steady state, the heat input to the reference catalyst 45 and the heat radiation from the reference catalyst 45 are balanced (heat input = heat radiation).

  As described above, when the temperatures of the detection unit catalyst 35 and the reference unit catalyst 45 become substantially constant and become a steady state, the calculation unit 6 sends the gas flow rate (V (liter / second)) and ammeter transmitted from the flow meter 21. Based on the current value transmitted from 52, the amount of heat is calculated.

  In the calculation, first, the calculation unit 6 obtains a temperature difference (td (° C.)) between the detection unit catalyst 35 and the reference unit catalyst 45 from the current value transmitted from the ammeter 52. As described above, the heating circuit unit 5 forms a Wheatstone bridge, and the current value detected by the ammeter 52 is the detection unit heating element 36 (first resistor) and the reference unit heating element 46 (in the steady state). This is due to the difference in resistance value of the second resistor. The relationship between the temperature and the resistance value of the detection unit heating element 36 (first resistor) and the reference unit heating element 46 (second resistor) is determined in advance and stored in the calculation unit. The voltage value applied by the power source 51 and the resistance values of the third resistor 53 and the fourth resistor 54 are known and stored in the calculation unit. Therefore, the calculating part 6 calculates | requires the resistance value of the detection part heating element 36 (1st resistor) and the reference part heating element 46 (2nd resistor) from the detected said electric current value, and detects a detection part heating from the said resistance value. A temperature difference between the element 36 (first resistor) and the reference portion heating element 46 (second resistor), that is, a temperature difference (td (° C.)) between the detection portion catalyst 35 and the reference portion catalyst 45 is obtained.

Next, the calculation unit 6 uses the following equation (1) from the gas flow rate (V (liters / second)) and the obtained temperature difference (td (° C.)) to calculate the amount of heat (H1 (kJ / m ³ )) is obtained.

H1 = F1 (w × td) / V (1)
In the above equation (1), w is the mass (g) (known) of each oxidation catalyst portion (detecting portion catalyst 35, reference portion catalyst 45), and F1 is a predetermined constant.

  The calculation unit 6 displays the calculated heat value on the display device and records it in the memory in the calorimeter 1. Note that instead of or in addition to that, the calculation unit 6 may transmit the calculated value of heat quantity to an external device.

  In the present calorimeter 1, such a calorific value is continuously measured at a predetermined frequency (for example, every second).

  Note that the above equation (1) is in the steady state, and the difference between the heat input to the detection unit catalyst 35 and the reference unit catalyst 45 (that is, the heat release from each catalyst) having the same specifications is introduced and completely burned. The amount of heat released is based on the idea that each catalyst depends on the amount of heat that each catalyst has at that time. In addition, the specific heat of the detection part catalyst 35 and the reference part catalyst 45 is known.

  Further, F1 is determined in advance by performing the same measurement using a reference gas with a known calorie and applying the measurement value obtained from the measurement to the above equation (1). Note that F1 may be determined not as a constant but as a function of temperature.

  Next, confirmation of deterioration of the oxidation catalyst of the calorimeter 1 will be described. In order to confirm the deterioration of the oxidation catalyst (in particular, the detection unit catalyst 35), the value of the ammeter 52 is checked without periodically introducing gas. Thereby, the drift situation of the zero point can be grasped. If the current value detected by the ammeter 52 is not zero, it is considered that the zero point is drifting, and if the width is increasing or decreasing, it is assumed that the oxidation catalyst has deteriorated. The deterioration check may be automatically performed by the calculation unit 6 at a predetermined timing (frequency). In this case, if it is determined that the battery has deteriorated, the fact is notified to the administrator of the calorimeter 1 using a display device or a communication device.

  Further, the catalyst and the heating element of the detection unit 3 and the reference unit 4 may be periodically exchanged (exchanged with each other), and the deterioration of the oxidation catalyst may be grasped from the change in the measurement result due to the exchange.

  The calorimeter 1 according to the present embodiment has been described above. However, as a modification, the air pipe 32 may not be provided. In this case, air necessary for gas combustion is naturally introduced from the periphery of the detection unit catalyst 35. In the form in which the air pipe 32 is not provided, it is not necessary to provide the air pipe itself and a device such as a blower for sending air, and the structure (configuration) of the device can be simplified.

  As another form, the air pipe 32 may be joined to the gas introduction pipe 31. In other words, a tip portion (opening portion) from which air from the air pipe 32 is released may be provided inside the gas introduction pipe 31. In this case, the position of the merge is between the downstream side of the flow meter 21 and the tip (opening) of the gas introduction pipe 31. By setting it as such a form, the gas and air mixed well beforehand are introduce | transduced around the detection part catalyst 35, and combustion can be made more perfect.

  As another variation, the detection unit catalyst 35 is formed of a porous body, the gas introduction pipe 31 is inserted into the detection unit catalyst 35, and the tip from which the gas in the gas introduction pipe 31 is ejected is in the vicinity of the detection unit heating element 36. It may be configured to reach FIG. 3 is a diagram showing the embodiment.

  As described above, in the calorimeter 1 according to the present embodiment, the calorific value of the gas can be obtained based on the detected value (current value) of the ammeter 52 in the steady state. It is possible, and the calorimeter 1 can have a relatively simple structure.

  Further, a Wheatstone bridge circuit is used as the heating circuit, and the calorific value can be easily measured based on the current value.

  In addition, since the gas introduction pipe 31 is provided and the gas is guided to the vicinity of the oxidation catalyst (the detection unit catalyst 35), the gas to be measured is completely burned, and high-precision measurement is possible.

  Further, since the air pipe 32 is provided and oxygen is reliably guided to the combustion region, the gas can be completely burned.

  Furthermore, good combustion is achieved by opening the tip of the air tube 32 in the vicinity of the oxidation catalyst.

  Further, by opening the tip of the air pipe 32 inside the gas introduction pipe 31, gas and air mixed well in advance can be supplied around the oxidation catalyst, and combustion can be made more complete.

  Further, by forming the oxidation catalyst with a porous body and inserting the gas introduction pipe 31 into the porous body, the gas can be surely completely burned.

  The protection scope of the present invention is not limited to the above-described embodiment, but covers the invention described in the claims and equivalents thereof.

  DESCRIPTION OF SYMBOLS 1 Calorimeter, 2 Gas flow measurement part, 3 Detection part, 4 Reference part, 5 Heating circuit part, 6 Calculation part, 21 Flow meter, 31 Gas introduction pipe, 32 Air pipe, 35 Detection part catalyst, 36 Detection part Heating element 45 Reference unit catalyst 46 Reference unit heating element 51 Power source 52 Ammeter 53 Third resistor 54 Fourth resistor

Claims (8)

A calorimeter that measures the amount of heat (H) of continuously flowing gas,
A first oxidation catalyst into which the gas is introduced;
A second oxidation catalyst having the same specifications as the first oxidation catalyst, wherein the gas is not introduced to the surroundings;
A bridge circuit including a first resistor provided in the first oxidation catalyst and a second resistor provided in the second oxidation catalyst as elements of an electric circuit;
An ammeter for detecting a current between bridges of the bridge circuit;
When the voltage is applied to the bridge circuit, the first oxidation catalyst and the second oxidation catalyst are heated by the resistor, and the gas is introduced around the first oxidation catalyst, the ammeter detects the current. Obtaining a resistance value of the first resistor and the second resistor based on the current value obtained, obtaining a temperature difference (td) between the first oxidation catalyst and the second oxidation catalyst based on the resistance value; A calorimeter comprising: an arithmetic unit that obtains the heat quantity (H) of the gas based on the temperature difference (td) by the following formula (1) .
(1) H = F × w × td / V (where F is a predetermined constant, w is the mass of the first oxidation catalyst and the second oxidation catalyst, and V is the flow rate of the gas) is there.) In claim 1,
The calorimeter, wherein the bridge circuit is a Wheatstone bridge circuit. In claim 1 or 2, further,
A calorimeter comprising a gas introduction pipe for guiding the gas to the periphery of the first oxidation catalyst. In any one of Claims 1 thru | or 3, Furthermore,
A calorimeter comprising an air pipe for guiding air to the first oxidation catalyst. In claim 4,
A calorimeter, wherein a tip of the air pipe opens near the first oxidation catalyst. In claim 4,
A calorimeter characterized in that the tip of the air pipe opens inside the gas introduction pipe. In claims 3 to 6,
The first oxidation catalyst is composed of a porous body,
The gas introduction pipe extends to the vicinity of the first resistor of the first oxidation catalyst. A calorific value measuring method for measuring the calorific value (H) of gas flowing continuously,
A first oxidation catalyst into which the gas is introduced;
A second oxidation catalyst having the same specifications as the first oxidation catalyst, wherein the gas is not introduced to the surroundings;
A bridge circuit including a first resistor provided in the first oxidation catalyst and a second resistor provided in the second oxidation catalyst as elements of an electric circuit;
An ammeter for detecting an inter-bridge current of the bridge circuit,
A voltage is applied to the bridge circuit, the first oxidation catalyst and the second oxidation catalyst are heated by the resistor, the gas is introduced around the first oxidation catalyst, and a current detected by the ammeter A resistance value of the first resistor and the second resistor is obtained based on the value, a temperature difference (td) between the first oxidation catalyst and the second oxidation catalyst is obtained based on the resistance value, and the temperature difference is obtained. Based on (td) , calorie | heat amount (H) of the said gas is calculated | required by following (1) Formula . The calorie | heat amount measuring method characterized by the above-mentioned.
(1) H = F × w × td / V (where F is a predetermined constant, w is the mass of the first oxidation catalyst and the second oxidation catalyst, and V is the flow rate of the gas) is there.)

Images