Ultra-low NO.sub.x combustion apparatus

A combustion apparatus for minimizing the formation of NO.sub.x, the apparatus comprising:

• a combustion vessel having first and second spaced opposite ends and a substantially cylindrical longitudinally extending wall;
• an elongated orifice connected to said combustion vessel adjacent the second end thereof;
• a combustion chamber having a front end, a rear end and a longitudinally extending wall, said elongated orifice connected to said combustion chamber adjacent said combustion chamber front end;
• means for supplying fuel into the combustion vessel adjacent the first end thereof;
• means for tangentially supplying a first stream of air into said combustion vessel and for forming a cyclonic flow pattern of hot gases for sub-stoichiometric combustion within said combustion vessel, the sub-stoichiometric combustion product gases formed by said sub-stoichiometric combustion flowing from said combustion vessel through said elongated orifice into said combustion chamber;
• means for tangentially supplying a second stream of air into said orifice adjacent the front end of the combustion chamber and for forming a swirling air flow within said orifice and said combustion chamber for above-stoichiometric combustion therein;
• a gas swirler disposed adjacent the rear end of the combustion chamber and a substantially cylindrical cooling chamber extending axially beyond the rear end of the combustion chamber and substantially longitudinally aligned with said chamber;
• and
• heat exchange means surrounding and extending substantially throughout the axial length of the combustion chamber for absorbing heat and cooling the combustion gases therein.

A combustion apparatus for minimizing the formation of NO.sub.x, the apparatus comprising:

• a combustion vessel having first and second spaced opposite ends and a substantially cylindrical longitudinally extending wall;
• a combustion chamber having a front end, a rear end and a substantially cylindrical longitudinally extending wall, said combustion vessel fixed to said combustion chamber with the second end of said combustion vessel inserted into the front end of the combustion chamber;
• means for supplying fuel into the combustion vessel adjacent the first end thereof;
• means for tangentially supplying a first stream of air into said combustion vessel and for forming a swirling air flow within said combustion vessel for sub-stoichiometric combustion therein;
• a plurality of radially spaced tangential outlet nozzles disposed in the combustion vessel wall adjacent the second end thereof, said outlet nozzles being in communication with the combustion chamber for allowing the sub-stoichiometric combustion product gases generated within said combustion vessel to flow from said combustion vessel to the front end of said combustion chamber;
• a substantially cylindrical exit throat at the rear of the combustion chamber and aligned substantially concentrica therewith for exhausting hot gases from the combustion chamber, the exit throat having a diameter less than the diameter of the combustion chamber wall;
• means for tangentially supplying a second stream of air into said combustion chamber and for forming a cyclonic flow pattern of hot gases for above-stoichiometric combustion within said chamber;
• and
• heat exchange means surrounding and extending substantially throughout the axial length of the combustion chamber for absorbing heat and cooling the combustion gases therein.

A combustion apparatus for a boiler furnace to minimize NO.sub.x emissions, the apparatus comprising:

• a combustion vessel having first and second spaced opposite ends and a substantially cylindrical longitudinally extending wall of substantially uniform inside diameter, said combustion vessel adapted to have at least said second end disposed in the boiler furnace;
• means for supplying fuel into the combustion vessel adjacent the first end thereof;
• means for tangentially supplying a first stream of air into the combustion vessel and for forming a swirling air flow within said combustion vessel for sub-stoichiometric combustion therein;
• means for allowing the sub-stoichiometric combustion product gases generated in the combustion vessel to flow into the boiler furnace;
• and
• means for tangentially supplying a second stream of air into the boiler furnace and for forming a cyclonic flow pattern of hot gases for above-stoichiometric cyclonic combustion within the furnace.

A combustion apparatus for minimizing the formation of NO.sub.x, the apparatus comprising:

• a combustion chamber having a front end, a rear end and a substantially cylindrical longitudinally extending wall;
• means for supplying fuel into the combustion chamber adjacent the front end thereof;
• air supply means for tangentially supplying a first and second stream of air into the combustion chamber at spaced intervals along the axial length of said combustion chamber for sub-stoichiometric combustion and above-stoichiometric combustion, respectively, within said combustion chamber and for forming a swirling flow pattern of hot gases for combustion within said combustion chamber, the air supply means comprising an air plenum chamber disposed in the combustion chamber, said air plenum chamber having a diameter less than the diameter of said combustion chamber wall for forming an annular space therebetween, said air plenum chamber including an air inlet and a first and second group of radially spaced tangential nozzles disposed in spaced axial relationship to each other for supplying the first and second stream of air, respectively, in said annular space;
• and
• heat exchange means surrounding and extending substantially throughout the axial length of the combustion chamber for absorbing heat and cooling the combustion gases therein.

A combustion apparatus for minimizing the formation of NO.sub.x, the apparatus comprising:

• a combustion vessel having first and second spaced opposite ends and a substantially cylindrical longitudinally extending wall, said wall including an inner and outer shell;
• an elongated orifice connected to said combustion vessel adjacent the second end thereof;
• a combustion chamber having a front end, a rear end and a longitudinally extending wall, said elongated orifice connected to said combustion chamber adjacent said combustion chamber front end;
• means for supplying fuel into the combustion vessel adjacent the first end thereof, said fuel supplying means including a fuel plenum chamber disposed between the inner and outer shells of the combustion vessel, the fuel plenum chamber having a fuel inlet and a plurality of radially spaced axial fuel nozzles communicating with the combustion vessel;
• means for tangentially supplying a first stream of air into said combustion vessel and for forming a cyclonic flow pattern of hot gases for sub-stoichiometric combustion within said combustion vessel, the sub-stoichiometric combustion product gases formed by said sub-stoichiometric combustion flowing from said combustion vessel through said elongated orifice into said combustion chamber, the means for supplying the first stream of air into the combustion vessel including a primary plenum chamber disposed between the inner and outer shells of the combustion vessel, said primary plenum chamber having an air inlet and a plurality of radially spaced primary air tangential nozzles communicating with the combustion vessel;
• means for tangentially supplying a second stream of air into said orifice adjacent the front end of the combustion chamber and for forming a swirling air flow within said orifice and said combustion chamber for above-stoichiometric combustion therein;
• and
• heat exchange means surrounding and extending substantially throughout the axial length of the combustion chamber for absorbing heat and cooling the combustion gases therein.

A combustion apparatus for minimizing the formation of NO.sub.x, the apparatus comprising:

• a combustion chamber having a front end, a rear end and a substantially cylindrical longitudinally extending wall;
• means for supplying fuel into the combustion chamber adjacent the front end thereof;
• air supply means for tangentially supplying a first and second stream of air into the combustion chamber at spaced intervals along the axial length of said combustion chamber for sub-stoichiometric and above-stoichiometric combustion, respectively, within said combustion chamber and for forming a swirling flow pattern of hot gases for combustion within said combustion chamber, said air supply means comprising a primary air plenum chamber and a secondary air plenum chamber disposed coaxially in the combustion chamber, said secondary air plenum chamber including a first axial portion of a first predetermined diameter and a second axial portion of a second predetermined diameter greater than said first predetermined diameter, said primary air plenum chamber being axially coextensive with said first axial portion and having said second predetermined diameter, said second predetermined diameter being less that the diameter of said combustion chamber wall for forming an annular space therebetween, said primary air plenum chamber including an air inlet and a first group of radially spaced tangential nozzles for supply the first stream of air into the annular space and said secondary air plenum chamber including an air inlet and a second group of radially spaced tangential nozzles for supplying the second stream of air into the annular space;
• and
• heat exchange means surrounding and extending substantially throughout the axial length of the combustion chamber for absorbing heat and cooling the combustion gases therein.

A combustion apparatus for a boiler furnace comprising:

• means for supplying fuel into the boiler furnace;
• and
• air supply means for tangentially supplying a first and second stream of air into the boiler furnace at spaced intervals along the axial length of the furnace and for forming a cyclonic flow pattern of hot gases for combustion within the furnace, the first stream of air causing sub-stoichiometric combustion and the second stream of air causing above-stoichiometric combustion, the air supply means comprising a primary air plenum chamber and a secondary air plenum chamber adapted to be disposed coaxially in the boiler furnace, said secondary air plenum chamber including a first axial portion of a first predetermined diameter and a second axial portion of a second predetermined diameter greater than said first predetermined diameter, said primary air plenum chamber being axially coextensive with said first axial portion and having said second predetermined diameter, said second predetermined diameter being less than the diameter of the furnace for forming a annular space therebetween, said primary air plenum chamber including an air inlet and a first group of radially spaced tangential nozzles for supplying the first stream of air and said secondary air plenum chamber including an air inlet and a second group of radially spaced tangential nozzles for supply the second stream of air.