The effect of rebuild on the combustion performance of an industrial gas-fired flat glass furnace

Post-rebuild profiles of velocity, species concentration (O-2 CO and CO2), and gas temperature are reported in the portnecks of a regenerative, side-p ort, 550-ton/day, gas-fired, flat-glass furnace. These measurements are als o compared to similar ones made before the same furnace was rebuilt. Measur ements were also made below one of the regenerators in the tunnel leading t o the furnace stack after the rebuild. Fewer variations were observed in th e exhaust profiles of most measured Variables after the rebuild. Flat inlet Velocity profiles were measured with a magnitude of approximately 11 m/s b efore and after the rebuild. The temperature of the inlet preheat air was g enerally speaking higher and the furnace exhaust temperature lower before t he rebuild. Locations of low O-2 concentration in the effluent are consiste nt with high CO concentrations before and after the furnace rebuild. CO2 co ncentrations are nearly uniform across the portneck height, more so after t he rebuild. The measurements in the tunnel after the rebuild indicate a str atification effect in the species concentration measurements. These measure ments also indicate that the combustion reactions continue inside the regen erators resulting in overall complete combustion as indicated by the very l ow CO levels in the tunnel. A mass balance analysis for the overall combust ion reaction based on the measurements of O-2 and CO2 and fuel flow rate in each port showed that (1) before and after the furnace rebuild the predict ed CO? formed in the glass is within 15% of the value estimated by Ford per sonnel; and (2) the overall stoichiometry was not much different before and after the rebuild (22.5% excess air before compared to 19.2% after). The t otal airflow rate calculated by this analysis after the rebuild is within 8 % of the plant-measured value.