Experimental Investigation on Combustion and Gas Emission of Scrap Tire Pellet under Various Concentrations of CO2/O2 Mixtures

Scrap tire is a typical waste fuel, for which the combustion in the form of pellets is a feasible way. In this work, the ignition behavior, combustion process and pollutant emission of the scrap tire in pellet form are explored. The experiments were performed in the vertical heating tube furnace under different coflow conditions in CO2/O-2 atmosphere. The temperature was set to 873, 973, 1073 K and the gas flow rate was set to 5, 10 and 20 L/min. The combustion images of scrap tire were recorded by the high-performance camera. The scrap tire pellet presented the characteristics of homogeneous ignition and the fly ash was captured around the scrap tire pellets. Increasing oxygen concentration and temperature shortened the ignition delay time and reduced the internal ignition temperature. The splash flame occurred during the volatile combustion under the conditions of high temperature, high oxygen concentration, and high gas flow rate. The distinct pores and cracks were found on the surface of char during the char combustion. The yields of pollutant gas increased as the gas flow rate increased from 5 to 20 L/min. With the increase of temperature, the emission of NO and SO2 was increased but NO2 emission was decreased.