Temperature-Dependent Pyrolysis of Wood Chips in a Fixed-Bed Reactor: Effects on Syngas and Charcoal Yield and Quality

In the context of the global challenge of reducing greenhouse gas and pollutant emissions from thermal and power generation systems, the utilization of secondary fuels, particularly biomass waste, is gaining increasing importance. One promising approach is the thermochemical conversion of wood waste via pyrolysis, which enables the production of energy carriers (syngas and charcoal) with minimal environmental impact. This paper presents a series of variable experiments conducted with wood chips at temperatures ranging from 360 to 520 °C. The optimal pyrolysis temperature was identified as 480 °C, yielding the highest values for the heating value of syngas (12.69 MJ/m³), mechanical gas efficiency (84.9%), and cold gas efficiency (25.8 %). It was also demonstrated that, as temperature increases, charcoal yield decreases from 36% to 27.5%, while gas yield rises from 11.1% to 19.5 %; the yield of liquid products remains relatively stable (~30%). Notably, above 250 °C, the pyrolysis process involves self-gasification of charcoal by pyrolytic gas. Additionally, the physicochemical and morphological characteristics of the resulting charcoal, including elemental composition, ash content, porosity, and surface structure, were investigated. The results contribute to the systematic understanding of how temperature affects the distribution and properties of pyrolysis products under fixed-bed conditions and can be applied in the development of energy-efficient and environmentally safe technologies for wood waste utilization.