Various 
smoke and 
combustible gas combustors (200, 300) are disclosed, and also disclosed are systems (100, 200) combining gas 
combustor with inventive burner. Such a burner (100 or 100') provides 
combustion of a particulate fuel such as 
sawdust, and many types of varying 
moisture content 
biomass fuels such as 
poultry litter. The combustors and burners exhibit a high turndown ratio ["TDR"].The 
smoke or 
combustible gas combustors (200, 300) are combined synergistically with such a burner (100, 100'), or combined with another suitable burner, so as to provide high temperature burner output gases to the 
combustor, which has coaxial inner and outer 
combustion chambers (352, 356) inlet 
tuyere(s) connected to the inner 
combustion chamber for introducing combustible 
smoke or other gases to be burned into the inner 
combustion chamber at one end thereof with cyclonic flow, and in which combustion air is mixed with combustible smoke or other gases to form a gas 
stream moving through the inner 
combustion chamber with cyclonic movement. A preheat tube (331) within the 
combustible gas heating chamber receives heated exhaust gases from the burner, and communicates with the inner 
combustion chamber exit through a plurality of apertures (364) for controlled flow of said heated exhaust gases into the gas 
stream and so heating same by mixing the exhaust gases with the 
stream of air and combustible gases.