Comparison of energy properties of pellets from shells of different nut species

Abstract

Bio-waste is a source of energy-rich material. Therefore, it can be used in further processes and efficiently utilized. Further processes of waste utilization include compressing them to pellets. However, this type of pellet often has a low bulk density, high ash content, low ash melting temperature, and low calorific value. This research dealt with the energy properties of peanut and pistachio nut shells that were pure or mixed with spruce sawdust in half proportion and compressed into pellets. As a continuation of previous research, the properties of these pellets prepared were measured and compared with pure spruce pellets and with pellets from walnut shells. The tested shell pellets had calorific values similar to wood pellets from spruce. However, mixing nut shells with spruce solved the problems of high ash content and low ash melting temperatures. The amount of wood present in the pellets resulted in increased ash melting temperatures and decreased the ash content.