gas analyzer / nitrogen oxide / temperature

The Need
Combustion gas measurements for NOx efficiency and product quality are especially challenging in the glass container manufacturing process. Two types of gas-fired furnaces exist that require post and pre combustion gas analysis. The glass furnace or "melt-tank" is fired by conventional burners that mix pre-heated air and fuel in the burner nozzle. Ambient air leakage in the heat re-cooperation structure can generate thermal NOx in the combustion flames while creating significant thermal energy losses. Flue gas temperature and vaporized glass particulates limit economical excess oxygen analysis to spot sample measurements at opposing-burner checker ports.

Molten glass leaving the glass furnace is transported to container forming equipment through the forehearth furnace. The fore hearth furnace contains several premix burner zones arranged along the length of the furnace walls. Temperature and atmosphere in each combustion zone is controlled by precise air/fuel ratio adjustment of discrete pre-mix gas stations. Ware of leading edge orifices, mixture diaphragms, and play in valve linkages can cause significant variance in air/fuel ratio set points. Periodic sampling and analysis of these discrete premix gas stations is necessary to maintain zone temperature balance for proper glass flow and homogenization as well as zone atmosphere control for color stabilization and curing.