Pellet Fuel Performance of Several Tree Species in a Secondary Forest in Changbai Mountain

Characteristics of pellet fuels from several tree species in a secondary forest in Changbai Mountain were investigated and analyzed in this study. Results showed that the highest ash content was 11.90% for corn straw, and the lowest is 0.37% for Abies holophylla, of the seven pellet fuels of interest. It was also found Populus si- monii had the largest ash-free caloric value (20896.05J), followed by the mixture of Tilia amurensis, Tilia mand- shurica, and Betula platyphylla (20885.15J), all larger than that of straw pellet. Ash-free calorific value for peeled Betula platyphylla was larger than that for the unpeeled, and the same result was found in axial load, radial load and oozing rate. The largest axial load is 0.2355kn for mixed wood, presenting the largest axial counter-pressure, and the second largest is 0.2149kn for peeled Abies holophylla. The radial load is 0.6402kn and 0.6242kn for peeled Betula platyphylla and mixed wood, respectively, demonstrating the largest and the second largest radial counter-pressure. Weight loss rate is 0.1316% and 0.1438%, respectively for Populus simonii and mixed wood, lower than other four types of pellet. Mixture of Tilia amurensis, Tilia mandshurica, and Betula platyphylla meas- ured the highest oozing rate, about 10.235%, and it is 10.233% for peeled Betula platyphylla. Six types of wood pellet were all deformed after 20 hours in waterborne impermeability experiment except mixed wood, which still remained granular. Different pellet fuels were significantly different in ash-free calorific value, axial load, and rate of impermeability (p<0.05).