Investigation of combustion and emissions of mixture of a wheat dust with binder pellet in a fixed-bed combustor

Abstract

The combustion behavior and gaseous emissions of wheat dust pellet at various operating parameters such as air temperature, pellet size, and air velocity are evaluated to achieve a better combustion performance. The results showed that as air temperature and air velocity increase as well as pellet size decreases, ignition time, char time, time to reach maximum temperature decreases and total combustion rate increases. It was concluded from the results that, a hexagonal pellet is the best shape for combustion under the investigated conditions and parameters due to its lowest ignition temperature, lowest surface temperature, shortest ignition time, and longest time required for combustion. CO2 content reaches its maximum value at air temperature 4000C for all pellets. The maximum CO concentration occurs at the highest diameter of the pellet. The combustion efficiency ranged between 99% to 100%. The wheat dust pellet has a medium slagging tendency (slagging index=0.72) and a relatively high fouling inclination (fouling index=1.88). The activation energy of a wheat dust pellet and a binder is 102.05 and 109.62kJmol-1, respectively, using TG data and kinetics model. The ignition time, the maximum combustion rate time and the burnt temperature of epoxy 1092 are lower than that of the pellet.