(167b) Effects of Pellet Feed and Air Supply Rates On the Combustion Behavior of Spruce Pellets in a Grid-Type Stove

The growing attentions to the utilization of biomass as a heat and power productions via conventional burning has initiated this study of using spruce materials as a feedstock.  Unlike other types of biomass i.e. olive cake, apricot and peach stones, spruce is abundantly available and thus, suitable to use as a source of feedstock.  In this study, the pellet of spruce was combusted in a grid type combustion chamber (5 kW stove).  The stove consists of electric heater igniter, a screw feeder (2-18 g/min) and an air blower (0.6-1.0 NTP-m³/min).  To observe the combustion behavior, the concentration of O₂, CO, NO and NO₂ were measured continuously using a combustion gas composition sensor (Hodaka HT-2000).  For each run, approximately 20-25 min of combustion under constant pellet feed and air supply was conducted. It is interesting to observe that combustion showed two phases cyclically with one of the cycles is flaming while other char is glowing.  It is expected that the behavior of gas composition in the form of cyclic period and amplitude due to the combustion condition.  The details would be discussed in the full paper.