Oxygen content control in heating furnaces
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What is the oxygen content control index for heating furnaces? Correspondence with carbon monoxide
In atmospheric and vacuum box furnaces, the oxygen content is controlled at around 4% during normal operation. The control for diesel hydrogenation cylinder furnaces is around 7%
The hydrogen production converter is also around 4%
If the oxygen level in the heating furnace is kept at 3% to 4%, the nitrides will not meet the required standards; if it is too low, the furnace temperature won’t rise enough, resulting in incomplete combustion and an increased risk of carbon monoxide formation. To prevent the generation of carbon monoxide, the furnace temperature needs to be above 600 degrees Celsius for such compounds to decompose.
High CO levels may occur when the furnace temperature is below 700°C. Flame instability and extinguishment may occur when the furnace temperature is below 650°C and the excess oxygen level is above 6–8%, or when the bottom of the furnace is below 540°C. It is necessary to measure the furnace bottom temperature in order to identify operating conditions that may cause flame instability. For heating furnaces equipped with low NOx burners, the oxygen content in the furnace needs to be controlled at around 3%. Only then can the burner achieve reasonable emission levels. With too high an oxygen content, NOx levels increase rapidly.