Comparison of bio-oils from fast pyrolysis of spruce wood and olive stone in spouted and bubbling fluidized bed reactors

Fast pyrolysis of lignocellulosic materials has been widely recognized as a potential route for simultaneous biomass valorization, carbon-neutral fuel synthesis and fine chemicals recovery. Among various reactor technologies developed for biomass thermochemical conversion, fluidized reactors emerge as versatile, cost-effective solutions. Particularly, bubbling bed fluidized pyrolizers are widely used in this field. Innovative reactor designs, such as the spouted bed reactor, have recently garnered interest for fast pyrolysis applications. The special hydrodynamic regime of the spouted bed reactor is functional to produce bio-oil with high yields. In this study, fast pyrolysis tests of selected lignocellulosic biomasses (namely, olive stone and spruce wood pellets) were conducted employing two different technologies: a conventional bench-scale bubbling fluidized bed pyrolizer and a flat-base spouted bed reactor. The collected bio-oils underwent comprehensive characterization using a Gas Chromatography-Mass Spectrometry (GC-MS), where chromatographic peaks were identified using the NIST 11 mass spectral data library. A semi-quantitative approach was adopted to determine the relative content of each bio-oil component. A critical comparison was conducted between the bio-oils obtained from the two experimental setups, focusing on factors such as yield, water content, and chemical composition.