As an alternative to the usual float glass furnace design using air as oxidant and gas or fuel oil as fuel, AGC Glass Europe decided to introduce a furnace working with pure oxygen instead of air. Air contains around 21% oxygen and 79% nitrogen. The nitrogen is useless for the combustion process but at high temperature produces nitrogen oxides (NOx). Thus using pure oxygen instead of air helps to reduce the energy needed for the combustion (it is no longer necessary to heat up the nitrogen) and prevents the formation of NOx.
AGC Glass Europe also developed a system that re-uses heat from the flue gases to preheat the gas before it is injected into the furnace. This yields additional energy savings.
After six months of work and a large amount of investment, this furnace began operation at the end of 2008. The float furnace is the first in Europe to operate fully on oxycombustion and the first in the world to have the gas preheated. This prototype should serve as an example for our group, as one of the most ecological furnaces in the world.
The combination of oxycombustion and preheating reduces NOx emissions by 70%, SOx emissions by more than 30% and CO2 emissions by 25%! Moreover, when this furnace is fully implemented, the gain in energy should reach 25% compared with a traditional air furnace.
The performance of this furnace will be evaluated in terms of energy, environment, economy, quality etc., and the possibility of extending this technology to other AGC Glass furnaces will be considered for each float line.