There is a Servomex 2700 combustion gas analyzer for measuring oxygen % and COe (ppm) emissions in Flue gas of Hydrogen plant. Can anyone say why COe is fluctuating between 268 to 361 ppm. But the level should be below 200ppm.
Air contains 300-400 ppm CO2 depending on your location. So if you are burning H2 with water, the dominant product of combustion, you are seeing the residual unreacted CO2. The water vapor will scavenge some of the CO2 and later condense...so you are seeing the gas phase CO2.