Urban pruning waste has the potential to be used to produce biofuels and renewable energy in tropical regions

Abstract

Forest biomass can be used for heat and electricity generation; meeting energy demands on multiple scales. In urban areas, tree pruning is a significant yet often underutilized source of this biomass. Therefore, this work aimed to characterize the biomass from urban pruning for heat production, evaluating the physical and chemical parameters of the biomass in natura. For this, the pruning biomass was collected from the Urban Cleaning Company of the City of Recife (EMLURB/PCR), and five different areas were sampled, called Political-Administrative Regions (PARs). The physicochemical properties (moisture content, bulk density, and heating value) and the structural, elementary, and immediate chemical composition of the in natura biomass were analyzed. As for physical properties, pruning biomass has a high moisture content, requiring prior drying to generate energy, and sufficient heat value to produce heat energy. In addition, pruning biomass has a high ash content, which can compromise the durability of the kilns for energy conversion. As for structural chemistry, it presents high levels of holocellulose and normal levels of extractives and lignin. Therefore, depending on the proper management of pruning stubble, they have the potential to generate heat energy, at a rate of approximately 2.8 Tcal per year.