Reduction of NOx emissions in regenerative fossil fuel fired glass furnaces: a review of literature and experimental studies

摘要

The mechanism of nitrogen oxide (NOx) formation in combustion chambers of glass furnaces is briefly described. The most important parameters governing the NOx emissions of glass furnaces are discussed. Elimination or minimisation of conditions that cause the formation of nitrogen oxides in regenerative furnaces have been tested in industrial regenerative furnaces. They include: reduction of false air, low air excess in the combustion process, delayed mixing or stepwise mixing of fuel with (preheated) air and enhanced flame cooling by promoting soot formation. Results of the industrial tests are presented as well as data from literature. Primary measures for minimising NOx formation in combustion chambers of glass furnaces show their limitations with respect to glass quality (fining, early sulphate decomposition), refractory attack by reducing flue gases and deposition of more aggressive condensation products in the regenerator and beyond a certain point, other emissions (particulate, SO2, CO) may increase on further reductions in NOx emissions. The potential of primary measures in reducing NOx emissions from glass furnaces is still not known, since some possibilities have not been completely investigated, such as major combustion and burner port design changes and flameless oxidation combustion. In this paper results of such primary measures to achieve NOx emission reduction are reviewed and new observations are reported.