JPS6118984B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for measuring the calorific value of fuel gas using a catalytic combustion type gas detection element.

Conventionally, the calorific value of fuel gas has been measured by burning the fuel gas and measuring the temperature rise of water in a measuring device. However, this method has disadvantages in that it cannot be easily used because the calorimeter and its operation are complicated and expensive, and requires skill to operate.

This invention has been made in view of the above points. This invention will be explained below.

FIG. 1 is a schematic configuration diagram showing an example of a calorimetry device used in the present invention, in which 1 is a gas injector that injects fuel gas such as a sample gas or test gas into the calorimetry device using a micro cylinder, etc.; 3 is a circulation pipe, 3 is a pump that circulates the fuel gas, 4 is a catalytic combustion type gas detection element, and 5 is an instruction provided in the gas detection element, which is provided in proportion to the molecular combustion heat of the fuel gas. It is a total.

FIG. 2 shows an example of the connection between the contact firing type gas detection element 4 and the indicator 5. In this figure, R ₁ and R ₂ are resistors, 4' is a compensation element, and E is a power supply. The gas detection element is heated to 300 to 400°C, and when the fuel gas comes into contact with it and burns, the heat generated changes the resistance value of the resistor, so that an indication can be obtained from the indicator 5.

Now, in FIG. 1, a predetermined amount of fuel gas is injected into a circulation pipe 2 using a gas injector 1, and is circulated within the calorimeter measuring device for a predetermined period of time using a pump 3. This circulated fuel gas is sequentially combusted in the gas detection element 4, so that an indicator 5 is instructed to give an indication value proportional to the calorific value. The indicated value of the indicator 5 varies depending on the type of fuel gas, and also varies depending on the combustion time that has passed since the fuel gas was circulated and the gas detection element 4 started operating. This is shown in FIG.

FIG. 3 is a characteristic diagram showing the relationship between the combustion time of various sample gases in the gas detection element 4 and the indicated value of the indicator 5. In this figure, the changes in the indicated values with respect to the elapsed times t ₁ to _{t 6} are not constant for each sample gas. Here, the relationship between the calorific value due to combustion of each sample gas and the indicated value is expressed as shown in FIG. 4 based on the characteristic diagram of FIG. 3.

In FIG. 4, since the amount of combustion heat possessed by each sample gas is a unique value, this amount of heat is plotted on the horizontal axis. Next, for each sample gas, a certain period of time t ₁ to _{t 6}
The relationship between the indicated value and the amount of heat is expressed as a curve as shown in FIG. 4, with the indicated value at the elapsed time taken as the vertical axis and the elapsed time t ₁ to t ₆ of each detected gas as a parameter.

As is clear from Fig. 4, the curve of the value of t ₄ among the elapsed times t ₁ to _{t 6} is a smooth curve passing through the origin with a constant change in the relationship between the calorific value of each sample gas and the indicated value. The other elapsed times t ₁ to t ₃ ,
The values of t ₅ and t ₆ are irregular and do not show constant changes. Therefore, if the curve at the elapsed time _t4 is employed and created in this manner, the amount of heat of the gas to be tested can be easily determined from the indicated value of the indicator 5.

Next, a method for measuring the calorific value of the sampled unknown gas to be detected will be described.

The gas to be tested is burned in the gas detection element 4 for t ₄ hours using the method described above, and the indicated value on the indicator 5 at this time is read. For example, if the reading value is 30,
In FIG. 4, this indicated value 30 is found on the curve of elapsed time _t4 . If this obtained point is x, then this x
The amount of heat at this point is 10.2
It can be seen that ×10 ³ Kcal/m ³ .

In this way, the calorific value of various test gases can be measured by the method described above.

Although the above embodiment describes the measurement of the calorific value of the gas to be detected, as an application example of the present invention, it is also possible to find out what kind of gas it is from the measured calorific value. This is particularly effective in the case of a single gas.

As explained above, the present invention uses a catalytic combustion type gas detection element, brings each sample gas whose calorific value is known in advance into contact with the gas detection element for a certain period of time, and combusts it. Create a characteristic curve in which the relationship between the indicated value and the known amount of heat is a smooth curve that passes through the origin, burn the sampled gas to be tested for a certain period of time as above, and read the indicated value on the indicator. After that, the value of the calorific value can be determined from the indicated value of the characteristic curve diagram and the intersection on the characteristic curve, so the device and its operation are simpler than conventional calorimetric measuring devices, and no operational skill is required. It has the advantage of being able to accurately measure the calorific value of the gas under test in a short period of time. moreover,
According to this invention, there is also the advantage that the type of gas can be known from the measured amount of heat.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing an example of a calorimeter measuring device used in the present invention, FIG. 2 is a circuit diagram showing an example of the connection between a catalytic combustion type gas detection element and an indicator,
Figure 3 is a characteristic diagram showing the relationship between the combustion time of various sample gases in the gas detection element and the indicated value of the indicator;
FIG. 4 is a characteristic diagram showing the relationship between the calorific value of various sample gases and the indicated value for each combustion time. In the figure, 1 is a gas injector, 2 is a circulation pipe, 3 is a pump, 4 is a gas detection element, and 5 is an indicator.

Claims (1)

[Claims] 1 A certain amount of sample gas with a known calorific value is sequentially and individually circulated and burned for a predetermined time in a circulation circuit equipped with a catalytic combustion type gas detection element, and an indicator connected to the gas detection element is connected to the gas detection element. A characteristic curve diagram is created in which the relationship between each indicated value and the known heat amount of each sample gas is a smooth curve that passes through the origin, and the same constant amount of the gas to be tested is transferred to the circulation circuit. After reading the indicated value of the indicator after the same predetermined time as above has elapsed, the calorific value of the test gas is determined using the characteristic curve diagram. Calorie measurement method using combustion type gas detection element.