Effect of operating and design parameters on the gasification/combustion process of waste biomass in fixed bed downdraft reactors: An experimental study

► We performed an experimental study on biomass gasification/combustion in packed beds. ► We evaluate biomass size and air superficial velocity effects on flame front velocity. ► Under gasification, increasing air superficial velocity increases flame front velocity. ► The gasification process ended when the flame front reached its maximum velocity. ► Under combustion, increasing air superficial velocity decreases flame front velocity.