1.2.2 Gas drying
The effect of the optional gas drying device on the concentration of the measured gases shall be minimum. Chemical dryers are not an acceptable method of removing water from the sample.
1.2.3 Specifications of analyzers
The gas for NOx monitoring shall be analyzed, using ale analyzer described below.
For a non-linear analyzers, the use of line arizing circuits is permitted.
.1 Oxygen analyzer (O2 analyzer)
The oxygen analyzer shall be of a paramagnetic detector (PMD), a zirconium dioxide (ZRDO) sensor or an electrochemical (ECS) sensor..
Note: The interference of C02 and NOx shall be compensated in the electrochemical sensor.
.2 Nitrogen oxide analyzer (NOx analyzer)
The nitrogen oxide analyzer, measured on a dry basis, shall be of achemiluminescent detector (CLD) equipped with a nitrogen dioxide and monoxide converter, an electrochemical sensor (ECS), a zirconium dioxide sensor (ZRNOXD) or a heated chemiluminescent detector (HCLD). If the detector is equipped with nitrogen dioxide (N02) and monoxide (NO) conversion function, or measures NO and N02 simultaneously or independently, the N02/NO converter may be unnecessary.
If measured on a wet basis, the HCLD with converter maintained at above 333k (60℃) or a heated zirconium dioxide sensor shall be used. However, a water quench check (refer to the test item 8 of table 2 of the reference document 1 in this guideline) shall be satisfied.
1.2.4 Specifications of recording devices
The measurement data during NOx monitoring shell be recorded, using the following recording devices.
1.2.4.1 Electromagnetic recording device
.1 The device shall be capable of recording the date and time of measurement and the measured values and printing out the information.
.2 The data sampling frequency shall be above once per minute.
1.2.4.2 Strip chart recorder
.1 The effective recording width shall be at least 100 mm.
.2 The strip chart recorder shall be capable of selecting the chart speeds of minimum of 20 mm/hour to above 20 mm/min.
1.2.4.3 Other recording devices
The device shall have functions equivalent to those of the electromagnetic recording device or the strip chart recorder.
