Caracterização de biochars produzidos em condições controladas oriundos de serragem de madeira

Abstract

The use of wood-based waste in the form of biochar, for agricultural applications, can be an environmentally sound practice. However, there are still few studies on these residues for the production of biochar. The objective of this work was to evaluate the influence of particle size of wood sawdust (wood residues) on the biochar properties (pH, density and particle size distribution) and pyrolysis yields (gravimetric, liquid yield and noncondensable gases). The research was conducted in the Laboratory of Instrumentac¸ ˜ao e Sensores do N´ucleo de Pequisa em Produc¸ ˜ao e Conservac¸ ˜ao do Cerrado da Universidade Federal de Mato Grosso, campus universit ´ario de Rondon´opolis-MT. The experimental design was completely randomized with five sizes of sawdust particles: 19.0 to 9.50; 9.50 to 4.75; 4.75 to 2.00; 2.00 to 1.18 and 1.18 to 0.60 mm, with four replicates, making up 20 experimental units. The bicohars were produced at a pyrolysis temperature of 400 C by a residence time in the reactor of 1 h. The results of pH, density of the biochar and pyrolysis yields were subjected to analysis of variance and where significant to regression test, both up to 5 % error probabilities. The particle size of the sawdust presents significant statistical influence on the density of the biochar and on the pyrolysis gravimetric yield, both adjusted to the quadratic regression model, with the lowest density of biochar (0.07 g cm􀀀3) estimated by the model for the particle size of 7.28 mm and the lowest gravimetric yield (27.96%) estimated for the particle size of 7.74 mm. Particle size reduction of the biochar was observed, caused by the pyrolysis process and handling of the biochar, with some stabilization of the particle size around 0.60 mm.