Abstract |
The report describes a versatile batch incinerator that was designed and built in order to determine the effect of operational variables on the ignition and burning rates in a fuel bed under conditions similar to those encountered in municipal incinerators. Detailed concentration and temperature profiles within and above the fuel bed were obtained for different distributions of overfire and underfire air rates. These results were used to evaluate both the rate controlling processes and control strategies. It was concluded that for the synthetic refuse beds studied, internal diffusion within the burning elements was limiting and that drying, pyrolysis, and gasification were contemporaneous through most of the runs giving rise to burning rates and overfire gas compositions that were constant over most of a run. From the oxygen concentrations in the bed, it is concluded that low underfire air rates are desirable early and late in a burn, and that for a fully ignited bed the maximum air rate is determined more by consideration of ash carryover and channelling than by the bed's ability to consume the oxygen. (Modified author abstract) |