Further Observations of the Effect of Sample Probes on Pollutant Gases Drawn from Flame Zones

Abstract

The effects of gas sample probes and conditioning techniques on the measurements of flame- generated NO, NO₂, and CO have been further examined. (1) A low-pressure, condensation free sampling system was compared with a conventional system, which operated at higher pressure and involved H₂O condensation. The conventional system demonstrated apparent losses of CO and NO_x, in the range 10 to 50 percent. (2) Sampling from fuel-rich combustion and pyrolysis zones was examined. High NO₂-to-NO ratios, approaching unity, were measured repeatedly in the fuel-rich pyrolysis zone of a high-intensity recirculative flame.