in fluidizing pulverized solid fuel discharged into fuel transport passageway 38 in one illustrative embodiment a carbon dioxide co 2 capture and sequestration system 42 is used to capture carbon dioxide generated during combustion in burner unit 21 so that the captured carbon dioxide is used as the fluidizing gas 26 in another illustrative embodiment treated products of combustion 44 generated during combustion in burner unit 21 provide fluidizing gas in yet another embodiment air 46 from any suitable source is used as the fluidizing gas 26 as suggested in fig1 oxygen delivery system 18 includes an oxygen supply 50 an oxygen distribution system 52 a control system 54 and an oxygen sensor 56 it is within the scope of this disclosure to place the oxygen sensor in any suitable location to sense the concentration of oxygen in fluidizing gas 26 communicated to fuel supply tube 14 the oxygen concentration level sensed by oxygen sensor 56 is communicated to control system 54 as suggested diagrammatically in fig1 control system 54 is configured to provide means for operating oxygen distribution system 52 to vary or otherwise regulate the amount of oxygen supplied to oxygen fuel mixer 24 and to oxygen manifold 30 using control system 54 a system operator can cause an oxygen enriched yet not spontaneously combustible oxygen fuel transport mixture to be discharged from oxygen fuel mixer 24 into a downstream portion 43 of fuel supply tube 14 arranged to communicate with flame chamber 20 formed.