Recovery of agricultural and wood wastes: The effect of biomass blends on the quality of pellets

The generation of large volumes of agricultural residues and the environmental problems arising from rice production has led producing countries to seek alternatives for the disposal of the residues generated in the rice production chain. This study aimed to analyze the quality of pellets produced with different blends containing rice husk, rice straw, rice husk ash, and Pinus spp. shavings. We analyzed 7 treatments: T1 (75% Pinus spp. shavings and 25% Rice straw); T2 (30% Rice husk, 60% Rice straw and 10% Rice husk ash); T3 (100% Rice straw); T4 (25% Pinus spp. shavings and 75% Rice Straw); T5 (75% Pinus spp. shavings and 25% rice husk); T6 (30% Pinus spp. shavings, 30% Rice husk, 30% Rice straw and 10% rice husk ash); T7 (100% Pinus spp. shavings). To verify the quality of the pellets, we analyzed the results according to the criteria of the ISO 17225-6 standard, considering the household and commercial use categories. Results showed that the rice straw and the Pinus spp. shavings are the raw materials that most change the pellets' physical and energetic properties. The inclusion of rice straw in the blends improve the pellets' physical properties. Similarly, the inclusion of Pinus spp. shavings in the blends improve the pellets' energetic properties. According to the ISO 17225-6 criteria, the pellets produced with 75% of Pinus spp. shavings and 25% of rice husk (25%) are the best among the analyzed treatments (T5).