Abstract: A system for burning biomass to produce hot gas including a wood processing system, a combustor, a cyclone ash separator, a turbine, and a control system. The wood processing system serves to process, dry and prepare the biomass for injection into the combustor. The biomass is injected into the bottom of the combustor. Combustion of the biomass takes place in the combustor. The resultant combustion gas enters the cyclone ash separator for removal of ash in the combustion gas. The cleaned combustion gas exits the cyclone ash separator via a duct. An air bypass assembly (104) permits and controls a flow of bypass air (129) from an annulus 98 of the cyclone ash separator into the duct to combine with the combustion gas. The combustion gas and bypass air (129) enter the turbine, where they expand to power the turbine.