Combustion measurements and modelling in an oxygen-enriched aluminium-recycling furnace

New measurements of gas temperature and composition in an industrial, oxygen-enriched, natural-gas-fired, aluminium-recycling furnace were obtained and compared with model predictions for the purpose of characterizing the combustion performance of the furnace acid evaluating the model. Exhaust temperature and concentrations of O-2, CO2, CO and NO were measured for oxygen enrichment levels of 31 to 39% (21% corresponding to air firing) and overall stoichiometry varying from 1.98 to 2.30 moles of oxygen per mole of fuel (2.0 being the stoichiometric mole ratio for the combustion of methane). Detailed profiles of O-2, CO2 and CO concentration in the combustion space and incident radiation flux at the sidewall were also determined experimentally at one operating condition. Measured NO increased with increasing oxygen enrichment. Predicted roof temperature was sensitive to aluminium dress thickness. Turbulent mixing was overpredicted by the model, and CO was underpredicted near the burners, probably due to kinetic effects, which were neglected.