JP3769879B2 - Gas concentration measuring device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gas concentration measuring device that measures the concentration of a target component (NOx, SO ₂ , CO, O _2, etc.) in a sample gas, and more particularly to an exhaust gas concentration measuring device that measures the concentration of a target component in the exhaust gas of a combustion engine. is there.
[0002]
[Prior art]
The measured value of the oxide concentration that is regulated by the Air Pollution Control Law is determined to be obtained as a value converted into a reference residual oxygen concentration state by the following equation (1) when NOx is taken as an example.
C = (21−On) · Cs / (21−Os) (1)
However, C is the converted NOx concentration (ppm), Cs is the measured NOx concentration value (ppm) in the exhaust gas, On is the reference residual oxygen concentration (vol%), and Os is the measured oxygen concentration value (vol%) in the exhaust gas. Numerical value 21 is the oxygen concentration (vol%) in the atmosphere.
For example, when the equipment to be measured is a boiler, NOx and O ₂ contained in the exhaust gas during boiler operation are measured a plurality of times, and the converted value of NOx is calculated from NOx and O ₂ at the time of each measurement, and the average of them is calculated. Check if the value is within the emission standards set by the Air Pollution Control Law.
[0003]
Depending on the equipment to be measured, operation and suspension are repeated in a short time. When measuring with a dry type (infrared analyzer, etc.) gas concentration measurement device, the measurement is usually not performed intermittently according to the operation of the equipment to be measured. The average value is calculated by extracting only the data at the time of operation of the measurement target equipment.
In addition, when measurement or measurement value storage is interrupted according to the operation / pause of the measurement target equipment, the measurement target equipment is provided with means for operating the operator or outputting a signal corresponding to the operation / pause. Is provided in the measuring apparatus.
[0004]
[Problems to be solved by the invention]
In the case of continuous measurement, there is a problem that it takes time and labor to extract only the data at the time of operation of the measurement target equipment and calculate the average value.
In addition, when the measurement is to be interrupted, the manual operation becomes complicated in the case of manual operation, and in the case of automatic, means for outputting a signal corresponding to operation / pause to the measurement target equipment, and the pause signal from the measurement target equipment There is a problem that it is expensive to provide the measuring device with a means for inputting.
Therefore, the present invention aims to automate the calculation of the average value, simplify the operation, and reduce the cost of the gas measuring device.
[0005]
[Means for Solving the Problems]
The present invention relates to a gas concentration measuring apparatus having a calculation unit that measures a specific oxide gas concentration in exhaust gas of a combustion engine and obtains an average value within a certain time, and measures an oxide gas concentration measurement value and other component gas measurements. Gas comprising a judgment / calculation unit that compares a value with a preset threshold value, judges operation / stop of the combustion engine based on the comparison result, and calculates an average value by omitting data during the stop It is a concentration measuring device.
For example, the concentration of oxide and O ₂ contained in the exhaust gas regulated by the Air Pollution Control Law is always measured by the detector, and the measured values of both oxide and O ₂ are stored in advance in the storage. By comparing the threshold value with the judgment / calculation unit, it is automatically judged whether the measurement target equipment is operating data or inactive data. The average value of the measured values within a certain time is calculated by automatically omitting the data during the pause.
[0006]
【Example】
As an embodiment of the present invention, an example of a NOx measuring device using a NOx detector and an O ₂ detector as a detection unit will be described. FIG. 1 is a block diagram showing the configuration of a NOx measuring apparatus according to one embodiment.
The NOx measuring device, NOx detector 1 for detecting the NOx contained in exhaust gas, O ₂ detects the O ₂ detector 2, the average value calculation start signal and the input unit 3 for inputting an end signal, the threshold value Ya Storage unit 4 for storing measurement values, detection signal concentration calculation, conversion value or average value thereof, judgment / arithmetic unit 5 for determining operation / pause of measurement target equipment by comparing with threshold value, and measurement It is comprised from the output part 6 which outputs data.
[0007]
The NOx detector 1 is provided with a NOx detector, measures NOx contained in the exhaust gas, and outputs a detection signal to the determination / calculation unit 5. The O ₂ detector 2 is provided with an O ₂ detector, measures O ₂ contained in the exhaust gas, and outputs a detection signal to the determination / calculation unit 5.
The determination / calculation unit 5, the storage unit 4, the input unit 3, and the output unit 6 in FIG. 1 may use a dedicated control / data processing device that controls the operation of the measurement device and processes data, or a general-purpose device. It may be realized by a computer.
[0008]
FIG. 2 shows an example of measurement data for NOx concentration measurement including data when the measurement target equipment is not operating. The x-axis indicates time, and the y-axis indicates concentration (% FS).
When the measurement target facility is not operating, the atmosphere is being measured, so that O ₂ ≈21 vol% and NOx≈0 ppm, and the conversion value calculated therefrom becomes small.
On the other hand, when the measurement target equipment is in operation, when it is burned in the atmosphere, O ₂ << 21 vol%, NOx >> 0 ppm, and the conversion value calculated therefrom is 0 ppm.
[0009]
FIG. 3 is a flowchart showing the operation of the embodiment, and the operation will be described with reference to FIGS.
The signals output from the NOx detection unit 1 and the O ₂ detection unit 2 are taken into the determination / calculation unit 5 at a certain sampling interval, and the NOx and O ₂ concentration values are respectively calculated. A converted value is calculated from these measured values according to equation (1) in step ST1.
If a measurement start or average value calculation start signal is input from the input unit 3, the determination at step ST2 is YES.
[0010]
In step ST3, the NOx threshold value or O ₂ threshold value stored in the storage unit 4 is compared with the NOx measurement value or O ₂ measurement value. Instead of comparing the NOx value, the threshold value of the converted value and the converted value may be compared.
As a result, NOx measurement value> NOx threshold value, or O ₂ measurement value <O ₂ threshold value, and when it is determined to be yes, that is, when it is determined that the measurement target equipment is in operation, each at step ST4 Is stored in the storage unit 4 as average value calculation data.
In step ST5, each value is output from the output unit 6 as measurement data.
[0011]
When it is determined NO in step ST3, that is, when it is determined that the measurement target facility is not operating, the measurement value and the converted value are not stored, and are output from the output unit 6 as measurement data in step ST5. .
If it is detected in step ST6 that the average value calculation end signal has not been input and it is determined no, the operations from step ST1 to step ST6 are repeated until the average value calculation end signal is input. If it is determined as YES in step ST6, that is, if an average value calculation end signal is input, it is stored as data during operation at the time between the input of the average value calculation start signal and the input of the average value calculation end signal. An average value of a plurality of converted values stored in the unit 4 is automatically calculated.
The respective threshold values stored in advance in the storage unit 4 are a NOx threshold value close to 0 ppm, an O ₂ threshold value close to 21 vol%, and a converted value threshold value close to 0 ppm. To do.
[0012]
The condition of step ST3 is determined by both the NOx value and the O ₂ value.
In the embodiment, an example is shown in which the present invention is applied to a NOx measuring apparatus, but the present invention apparatus can also be applied to an SO ₂ or CO measuring apparatus.
Since it is possible to determine whether the measurement target facility is in operation or not, it is preferable to stop the recorder or the like during the stop in order to reduce the use time of maintenance items such as paper and extend the replacement cycle.
[0013]
【The invention's effect】
Since only the data at the time of operation of the measurement target equipment is automatically extracted and the average value is calculated, it is possible to save the trouble of manually performing the work.
Since it is not necessary to interrupt the measurement in accordance with the operation / rest of the measurement target facility, the operation by the operator can be simplified.
Costs can be reduced because there is no need to provide means for outputting a signal corresponding to operation / pause to the measurement target facility and means for inputting an operation stop signal from the measurement target facility to the measurement apparatus.
Therefore, automation of calculation of the average value of the conversion value, simplification of operation, and cost reduction of the gas measuring device can be performed.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of an NOx measuring apparatus as an embodiment to which the present invention is applied.
FIG. 2 is a diagram showing an example of measurement data of NOx concentration measurement including data when the measurement target equipment is not operating.
FIG. 3 is a flowchart showing the operation of the embodiment.
[Explanation of symbols]
1 NOx detection unit 2 O ₂ detection unit 3 input unit 4 storage unit 5 judgment / storage unit 6 output unit

Claims (1)

In the gas concentration measuring device that measures the specific oxide gas concentration in the exhaust gas of the combustion engine and calculates the average value within a certain time,
The oxide gas concentration measurement value and other component gas measurement values are compared with a preset threshold value, and the operation / stop of the combustion engine is determined based on the comparison result, and the data during the stop is A gas concentration measuring apparatus comprising a determination / calculation unit that omits the average value and calculates the average value.

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