Experimental Study to Replicate Wood Fuel Conversion in a Downdraft Gasifier: Features and Mechanism of Single Particle Combustion in an Inert Channel

Downdraft gasification is a promising process of energy conversion wood biomass. There are such fuel conditions that differ favorably from conventional conditions. In conditions, there no pyrolysis zone in the bed, which precedes oxidation zone. Fuel supplied into oxidizing without charring, where it reacts with intensive cold air flow tuyeres. The study aims to replicate particles gasifier close For this purpose, individual burned muffle furnace space and quartz channel replicating presence other bed at first approximation. experiment, temperature was varied, as well velocity particle. Two-stage single-stage mechanisms particle combustion were identified. A two-stage observed range tuyere velocities below 20 m s−1. mechanism characterized by stage devolatilization volatiles combustion, followed char residue combustion. stages predominantly separate each other, their degree overlapping low, amounting 24%. At above 125 s−1 realized primarily process. reaches surface initiates layer. case, run concurrently for most part. mechanism, significantly higher amounts 60–95%. effect cyclic movement flame across evident. number cycles can reach eight. This due change stages. 95 s−1, fragmentation commences. layer formed an initial burning heats up separated surface. heated walls contribute intensification probably swirling between wall