NOx Reduction and Heat Transfer Characteristics in Gas Fired Glass Melting Furnaces

This paper describes the results of a series of experiments executed in 1988 at the IFRF for a consortium of gas companies. The main objective of the experimental programme was to investigate practical NOx reduction methods and their impact on the heat transfer characteristics for natural gas fired glass melting furnaces. In the research programme, a semi-industrial scale (0.75 MWt) compartment of an underport fired glass melting furnace was simulated. In total, 130 different flames were studied with NOx emissions varying from 80 to 4200 ppm. The most promising results with respect to NOx reduction were obtained by optimisation of the air-fuel mixing characteristics. Reduction in NOx emissions by up to 75% were achievable in some cases, while corresponding heat transfer was maintained at an acceptable level. Results are also reported on the effect of: excess air, air preheat temperature, water injection, fuel cracking and thermal input variation.