There are a number of conventional solutions to increasing output and product flow rate in a standard air/fuel combustion furnace. Solutions include increasing the length of the furnace and the number of burners, improving flue gas heat recovery to improve preheating, installation of alternating regenerative burners to preheat combustion air and charging hot billets directly from a previous production operation. Major features of all of these are high investment and length of downtime required to refurbish or refit the furnace. In addition, preheating air can result in unwanted high NOx emissions and an increase in scale (oxidation) on the heated billets.
The use of pure oxygen instead of air for combustion has both efficiency and product quality advantages including: