JP2787964B2 - City gas combustion rate measurement method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring the burning rate of city gas.

[0002]

2. Description of the Related Art Conventionally, CP (combustion rate index) has been used as an index of the combustion rate of city gas. However, the adoption of a new index to more correspond to the current situation is being determined. (See the Gas Business Newspaper dated March 7, 1991.) This index (MCP) is calculated by the following formula. Index MCP = {(ΣSi ・ fi ・ Ai) / (Σfi ・ Ai)} ・ {1-K (N ₂ + N ₂ ² + 2.5CO ₂ )} where K = (ΣAi) / (Σαi ・ Ai) N ₂ = {[N ₂ ] -3.77 [O ₂ ]} / {100-4.77 [O ₂ ]} CO ₂ = [CO ₂ ] / {100-4.77 [O ₂ ]} Si: Maximum combustion of combustible single gas Speed fi: Coefficient specific to combustible simple gas Ai: Combustible simple gas component in mixed gas (%) αi: Decay constant due to inert gas [N ₂ ]: N ₂ component in mixed gas (%) (CO ₂ ): CO ₂ component (%) in the mixed gas (O ₂ ): O ₂ component (%) in the mixed gas Therefore, to obtain this index MCP, it is necessary to measure the proportion of the city gas component. is there.

Heretofore, in measuring the components of city gas, a small amount of a gas sample has been sampled from a supply line and analyzed by an analyzer such as a gas chromatograph to measure the proportion.

[0004]

In such a conventional measuring method, the components of the gas being supplied and the burning rate cannot be measured continuously and without a time delay.
There is a problem that a plurality of types of analyzers having an expensive gas composition are required and the cost is high. An object of the present invention is to solve such a problem.

[0005]

In order to solve the above-mentioned problems, the present invention provides a measuring line branched from a city gas supply line, which is provided with a sensor for measuring a ratio of a combustion rate calculation target gas. For hydrocarbons other than methane, the ratio of the total amount and the ratio of the butane amount are measured, and the hydrocarbons other than methane and butane obtained by subtracting the butane amount from the total amount are approximated as propane,
The present invention proposes a method for measuring the combustion speed of city gas, which calculates an index of a predetermined combustion speed from the respective proportions of these combustion speed calculation target gases.

In the above method, the sensor for measuring hydrocarbons other than methane can be an infrared gas sensor.

[0007]

The respective ratios of the combustion speed calculation target gas in the measurement gas branched from the city gas supply line and flowing into the measurement line are measured by sensors, and based on these values, the corresponding amount of the combustion speed is calculated by the calculating means. Is continuously calculated.

At this time, in hydrocarbons other than methane,
Butane is separated from the remaining components, and the ratio can be easily measured. On the other hand, in the case of city gas, the combustible gas to be mixed in calorific value control is mostly butane or propane.

Accordingly, with respect to hydrocarbons other than methane, the ratio of the total amount and the ratio of the butane amount are measured, and the hydrocarbons other than methane and butane obtained by subtracting the butane amount from the total amount are approximated as propane. Then, an index of a predetermined combustion speed can be calculated from each ratio of these combustion speed calculation target gases.

[0010]

Next, an embodiment of the present invention will be described with reference to the drawings.
In FIG. 1, reference numeral 1 denotes a city gas supply line, and the supply line 1 includes gases A, B, and C in a mixing section 2.
Are mixed and supplied at a predetermined ratio. A measurement line 3 branches off from the city gas supply line 1. A hydrogen sensor 4 and an oxygen sensor 5 are installed on the measurement line 3. These hydrogen sensor 4 and oxygen sensor 5
For example, a gas heat conduction type sensor (hydrogen), a diaphragm galvanic cell type sensor (oxygen), or the like can be used.

An infrared gas sensor 6 is provided downstream of the measurement line 3 from the sensors 4 and 5, and the downstream side of the sensor 6 is open to the atmosphere or the city gas supply line 1. It is configured to recirculate.
As shown conceptually in the figure, the infrared gas sensor 6 comprises a methane sensor unit 7, a carbon monoxide sensor unit 8, a carbon dioxide sensor unit 9 and a hydrocarbon sensor unit 10, respectively. The unit 10 includes a total amount sensor unit 11 for measuring the total amount of hydrocarbons other than methane and a butane sensor unit 12. Since the total amount of hydrocarbons other than methane can be obtained from the total amount of the measurement gas and the sum of the values of the sensors 4, 5 and the sensor units 7, 8, and 9,
The total amount sensor section 11 can be omitted.

The respective ratios of the combustion rate calculation target gas measured by the sensors 4, 5, and 6 are input to the calculating means 13 using a microcomputer or the like. Speed indicator MC
You can get P. In this calculation, in the present invention, the amount obtained by subtracting the amount of butane measured by the butane sensor 12 from the total amount of hydrocarbons other than methane measured by the total amount sensor unit 11 is calculated as propane.

FIG. 2 shows the infrared absorption spectrum of the main component of city gas. From this figure, it can be seen that butane can be clearly separated from other components of hydrocarbons other than methane and the ratio can be measured. Is shown.

On the other hand, in the case of city gas, the combustible gas to be mixed in the calorific value control is almost butane or propane, and the specific ratio is as shown in FIGS.
That is, FIG. 3 shows an example of a composition when the calorific value is adjusted by mixing propane, and FIG. 4 shows an example of a composition when the calorific value is adjusted by mixing butane.

In these compositions, the values obtained when the above-mentioned index MCP was calculated using hydrocarbons other than methane and butane as propane as described above, and the value obtained when this index MCP was calculated according to the definition formula are shown in FIG. It is shown in FIG.

When the present invention is applied as shown by the values of the index MCP, it can be seen that the index MCP can be calculated very accurately without measuring all the components of hydrocarbons other than methane.

The index of the burning rate obtained by the above method can be a conventional index CP.

[0018]

As described above, the present invention has the following effects. The burning rate of the supplied city gas can be measured continuously and without any time delay. An expensive gas composition analyzer such as a gas chromatograph is not required and the cost is low. Since it is not necessary to measure all components of hydrocarbons other than methane, the equipment configuration is simplified and the cost is low.

[Brief description of the drawings]

FIG. 1 is a system explanatory diagram conceptually showing a method of the present invention.

FIG. 2 is an explanatory diagram showing an infrared absorption spectrum of a main component of city gas.

FIG. 3 shows an example of a composition in a case where the calorific value is adjusted by mixing propane in city gas, and a result of calculating an index MCP of a burning rate based on the composition.

FIG. 4 shows an example of a composition in a case where the amount of heat is adjusted by mixing butane in a city gas, and a result of calculating an index MCP of a burning rate based on the composition.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 City gas supply line 2 Mixing part 3 Measurement line 4 Hydrogen sensor 5 Oxygen sensor 6 Infrared gas sensor 7 Methane sensor part 8 Carbon monoxide sensor part 9 Carbon dioxide sensor part 10 Hydrocarbon sensor part 11 Total amount sensor part 12 Butane sensor part 13 Calculation means

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-59-31433 (JP, A) JP-A-53-129990 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) G01N 33/22

Claims (2)

(57) [Claims] 1. A sensor for measuring the ratio of a combustion rate calculation target gas is provided on a measurement line branched from a city gas supply line. This sensor is used for a hydrocarbon other than methane to measure the ratio of the total amount and the butane amount. And hydrocarbons other than methane and butane, which are obtained by subtracting the amount of butane from the total amount, are approximated as propane, and an index of the predetermined combustion rate is calculated from the respective proportions of these combustion rate calculation target gases. Of measuring the combustion rate of city gas, characterized by calculating 2. The method for measuring the combustion rate of city gas according to claim 1, wherein the sensor for measuring hydrocarbons other than methane is an infrared gas sensor.