Test method for carbon monoxide in air (3)
1, the principle of
Carbon monoxide is separated from other components of the air in the column, and then enters the reformer. Under the catalysis of nickel catalyst at 360℃, carbon monoxide reacts with hydrogen to form methane, which is determined by hydrogen flame ionization detector.
CO+3H2 was catalyzed to CH4+H2O by Ni at 360℃
2.1 Carbon molecular sieve :TDX-01 60-80 mesh, as a host phasing.
2.2 Pure air: does not contain carbon monoxide or carbon oxide content lower than the detection limit of this method.
2.3 Nickel catalyst: 30-40 mesh, when CO<180mg/m3, CO2<0.4%, the conversion rate >95%.
2.4 Carbon monoxide standard gas: carbon monoxide content 10 ~ 40ppm (aluminum alloy steel cylinder) with nitrogen as the base gas.
3. Instruments and equipment
3.1 Gas chromatograph: Gas chromatograph equipped with hydrogen flame ionization detector.
3.2 Reformer; Controllable temperature 360±1℃.
3.4 and aluminum foil composite film sampling bag: volume 400 ~ 600ml.
3.5 Chromatological column: the non-dog steel tube with a length of 2m and an inner diameter of 2mm was filled with TDX-01 carbon molecular sieve, and the two ends of the column tube were filled with glass wool. Before use, the newly installed chromatographic column should be aged for 10h under the condition of column temperature 150℃, detector temperature 180℃, hydrogen 60ml/min. 3.6 Conversion column: stainless steel tube with length of 15cm and inner diameter of 4mm is filled with nickel catalyst (30 ~ 40 mesh) and glass wool is inserted at both ends of the column tube. The converter column is installed in the converter, one end is connected with the chromatographic column, and the other end is connected with the detector. Before use, the conversion column should be activated for 10h under the furnace temperature of 360℃ and hydrogen 60ml/min. The aging of transformation column was synchronized with the aging of chromatographic column. When CO<180mg/m3, the conversion rate > was 95%.
With rubber ball, the air on site is pumped into the sampling bag to swell up and then let go. If the eye is repeated four times, after the last full, seal the injection mouth, and write the label, indicating the sampling place and time, etc.