Combustion characteristics of simulated and shredded refuse

Abstract

An experimental batch incinerator was used to measure burning and ignition rates in simulated and shredded refuse beds. Provision was made for measurement of refuse weight and fuel bed temperature distributions during combustion as well as the concentrations of CO, CO 2 , H 2 , O 2 , and CH 4 within the fuel bed. The burning rates of the shredded refuse were found to be insensitive to the fineness of shredding but varied with fuel bed density. For loosely packed shredded refuse, overfire air penetrated the bed at low underfire air rates and augmented the burning rate. At high underfire air rates burning rates became ignition limited and burning bed depths were approximately constant during the steady burning regime. No difficulty was experienced in initially igniting the shredded refuse even when underfire air rates of 275 lb hr −1 ft −2 were employed at the start of a run. The fuel bed gas composition measurements suggested that the water gas shift reaction (CO+H 2 O agCO 2 +H 2 ) was close to equilibrium at the top of the bed; this result provides a rough guideline for determining overfire air requirements. For the simulated refuse drying and pyrolysis occurred for prolonged periods after the surface of the fuel element had ignited.