Production of pellets from pruning residues and determination of pelleting physical properties

Abstract

ABSTRACT Turkey is among the leading countries in fruit production. Every year important amounts of pruning residues emerge from orchards. These residues have significant energy potential. There is a lack of study on the physical properties of pellet production from different orchard residues. Assessment of these residues is of enormous significance for the environment and economy. Pelleting is one of the methods of evaluating these low-density residues. Particle size and moisture content are the most important factors affecting pellet quality. The aim of this study is to evaluate the pruning residues such as olive, vineyard and pomegranate as biofuels. For this, pruning residues were pelleted in a pellet machine. Different moisture contents (10-12% and 14-16%) and three different particle sizes (2, 4 and 6 mm) were used in the experiments. The physical properties of pellets such as particle density, bulk density, durability, tensile strength and absorption resistance were defined. Besides, energy consumption values and pellet production capacity were measured. At the end of the experiments, depending on the material properties and moisture content, average pelleting machine pellet production capacity was measured as 23–83 kgh−1 and cylindrical pellets with an average diameter of 6 mm were produced. The particle density and bulk density of pellets were between 981–1338 kgm−3 and 521–793 kgm−3, respectively, and pellet densities were decreased with increasing moisture content. In addition, the relation between physical properties was analyzed by using the analysis of variance (ANOVA) method using by IBM SPSS 17 software.