Patent ID: 8707877

Claim:
A method for combustion of a solid fuel with low NO x emissions and satisfactory burnout, comprising the steps of: supplying a flow of a primary oxidant from a first nozzle, the primary oxidant being industrially pure oxygen; supplying a flow of fuel from a first annulus disposed between the first nozzle and a second nozzle disposed concentrically around the first nozzle, the fuel being particulate coal and a carrier gas; supplying a flow of a secondary oxidant from a second annulus surrounding and coaxial with the second nozzle; combusting the fuel and primary and secondary oxidants to produce flue gas; and collecting and recycling a portion of the flue gas, wherein: the secondary oxidant is industrially pure oxygen mixed with a portion of the recycled flue gas, the recycled flue gas constituting 18.2-47.1% (vol/vol) of the secondary oxidant and the oxygen constituting the balance of the secondary oxidant; the carrier gas is a portion of the recycled flue gas; the primary oxygen is 2.7-10% (vol/vol) of the amount of oxygen in the flows of primary oxidant and secondary oxidant; a total amount of oxygen in the flows of primary oxidant, secondary oxidant, and fuel is 47% to 70% (vol/vol); and the percent burnout of the particulate coal being greater than 97.25% and less than 99.5%.