초록 ▼

A firetube boiler furnace having two combustion sections and an in-line intermediate tubular heat transfer section between the two combustion sections and integral to the pressure vessel. This design provides a staged oxidant combustion apparatus with separate in-line combustion chambers for fuel-ri

A firetube boiler furnace having two combustion sections and an in-line intermediate tubular heat transfer section between the two combustion sections and integral to the pressure vessel. This design provides a staged oxidant combustion apparatus with separate in-line combustion chambers for fuel-rich primary combustion and fuel-lean secondary combustion and sufficient cooling of the combustion products from the primary combustion such that when the secondary combustion oxidant is added in the secondary combustion stage, the NOx formation is less than 5 ppmv at 3% O2.

대표청구항 ▼

1. A fluid heating apparatus comprising:an elongated fluid containment vessel having opposed first and second end walls, said first end wall forming a first opening adapted to receive a burner and said second end wall forming a second opening, said second opening closed off by a fluid-cooled door co

1. A fluid heating apparatus comprising:an elongated fluid containment vessel having opposed first and second end walls, said first end wall forming a first opening adapted to receive a burner and said second end wall forming a second opening, said second opening closed off by a fluid-cooled door connected to said fluid containment vessel;a first stage burner secured to said first end wall, said first stage burner having a first stage fuel inlet, a first stage oxidant inlet, a first stage fuel outlet opening and a first stage oxidant outlet opening, and a first stage combustion chamber wall enclosing a first stage combustion chamber and forming at least one first stage combustion products outlet opening, said first stage combustion chamber disposed within said fluid containment vessel;a second stage burner disposed within said fluid containment vessel, said second stage burner having a second stage fuel inlet, a second stage oxidant inlet, and a second stage combustion chamber wall enclosing a second stage combustion chamber and forming at least one second stage combustion products outlet opening;at least one first tubular heat transfer element connecting said at least one first stage combustion products outlet opening to said second stage fuel inlet and providing fluid communication therebetween;at least one flow reversal wall forming a first flow reversal plenum within said fluid containment vessel, said first flow reversal plenum in fluid communication with said second stage combustion products outlet opening;at least one combustion products exhaust wall forming a combustion products exhaust plenum disposed within said fluid containment vessel downstream of said first flow reversal plenum, said combustion products exhaust plenum in fluid communication with said first flow reversal plenum; andat least one second tubular heat transfer element providing said fluid communication between said first flow reversal plenum and said combustion products exhaust plenum.2. An apparatus in accordance with claim 1, wherein said at least one first stage combustion chamber wall forms a plurality of openings providing fluid communication between said at least one first stage fuel inlet and said first stage combustion chamber.3. An apparatus in accordance with claim 1 further comprising at least one first stage mixer wall forming a first stage mixing chamber in fluid communication with said first stage fuel inlet, said first stage oxidant inlet and said first stage combustion chamber disposed upstream of said first stage combustion chamber.4. An apparatus in accordance with claim 1 further comprising a first stage recirculation sleeve disposed within said first stage combustion chamber, said first stage recirculation sleeve coaxially aligned with a first stage burner center axis of said first stage burner and having a first stage combustion products inlet end and a recirculated first stage combustion products outlet end.5. An apparatus in accordance with claim 4 further comprising a second stage recirculation sleeve disposed within said second stage combustion chamber, said second stage recirculation sleeve coaxially aligned with a second stage burner center axis of said second stage burner and having a second stage combustion products inlet end and a recirculated second stage combustion products outlet end.6. An apparatus in accordance with claim 5, wherein at least one surface of at least one of said first stage recirculation sleeve and said second stage recirculation sleeve is coated with a protective material.7. An apparatus in accordance with claim 5, wherein said second stage burner comprises at least one second stage oxidant plenum wall enclosing a second stage oxidant plenum upstream of said second stage recirculation sleeve.8. An apparatus in accordance with claim 4, wherein said first stage recirculation sleeve has a radial distance less than at least one radial distance of said first stage fuel outlet opening from said center axis.9. An apparatus in accordance with claim 4, wherein said first stage recirculation sleeve has a radial distance greater than at least one radial distance of said first stage fuel outlet opening from said center axis.10. An apparatus in accordance with claim 1 further comprising at least one first stage fuel distributor wall enclosing a fuel distribution plenum and forming said at least one first stage fuel outlet opening, said at least one first stage fuel outlet opening aligned with said at least one first stage oxidant outlet opening, whereby fuel and oxidant mix prior to entry into said first stage combustion chamber.11. A fluid heating apparatus comprising:an elongated fluid containment vessel having opposed first and second end walls, said first end wall forming a first opening and said second end wall forming a second opening, said second opening closed off by a fluid-cooled door connected to said fluid containment vessel;at least one wall enclosing a first stage chamber and forming at least one first stage fuel inlet opening, at least one first stage oxidant inlet opening and a plurality of first stage fuel/oxidant outlet openings, said plurality of first stage fuel/oxidant outlet openings formed by a portion of said at least one wall disposed on a first stage fuel/oxidant outlet side of said first stage chamber and disposed at at least one radial distance from a center axis of said first stage chamber;at least one first stage combustion chamber wall connected to said fuel/oxidant outlet side of said chamber, extending through said first opening, enclosing a first stage combustion chamber disposed in said fluid containment vessel in fluid communication with said fuel/oxidant outlet openings and forming at least one first stage combustion products outlet opening;at least one second stage combustion chamber wall enclosing a second stage combustion chamber disposed within said fluid containment vessel distal from said first end wall, said second stage combustion chamber wall forming at least one second stage fuel inlet opening in fluid communication with said at least one first stage combustion products outlet opening;oxidant inlet means for introducing second stage oxidant into said second stage combustion chamber;at least one first tubular heat transfer element connecting said at least one first stage combustion products outlet opening to said second stage fuel inlet opening;at least one flow control wall forming a first flow control plenum within said fluid containment vessel proximate said second end wall, said first flow control plenum in fluid communication with said second stage combustion chamber;at least one second flow control wall forming a second flow control plenum disposed within said fluid containment vessel proximate said first end wall, said second flow control plenum in fluid communication with said first flow control plenum; andat least one second tubular heat transfer element connecting said first flow control plenum to said second flow control plenum.12. An apparatus in accordance with claim 11 further comprising a first stage recirculation sleeve disposed in said first stage combustion chamber and coaxially aligned with said center axis, said first stage recirculation sleeve having a combustion products inlet end proximate said fuel/oxidant outlet side of said first stage chamber and a recirculated combustion products outlet end distal from said fuel/oxidant outlet side of said first stage chamber.13. An apparatus in accordance with claim 12 further comprising a second stage recirculation sleeve disposed within said second stage combustion chamber, said second stage recirculation sleeve coaxially aligned with said center axis and having a second stage combustion products inlet end oriented towards said first stage combustion chamber and a recirculated second stage combustion products outlet end distal from said first stage combustion chamber.14. An apparatus in accordance with claim 13 further comprising at least one second stage oxidant plenum wall disposed within said second stage combustion chamber enclosing a second stage oxidant plenum upstream of said second stage recirculation sleeve, said second stage oxidant plenum wall forming at least one second stage oxidant outlet opening, thereby providing fluid communication with said second stage combustion chamber.15. An apparatus in accordance with claim 14, wherein a refractory material is disposed on a side of said second stage oxidant plenum facing said second stage recirculation sleeve, said refractory material forming at least one refractory opening aligned with said at least one second stage oxidant outlet opening.16. An apparatus in accordance with claim 14, wherein at least one mixing tube having a longitudinal axis is disposed within said second stage oxidant plenum and aligned with said at least one second stage oxidant outlet opening, said longitudinal axis oriented substantially parallel to said central axis and said at least one mixing tube in fluid communication with said at least one first tubular heat transfer element.17. An apparatus in accordance with claim 16, wherein a mixing tube wall of said mixing tube forms at least one mixing tube opening, providing fluid communication between said second stage oxidant plenum and an interior of said mixing tube.18. An apparatus in accordance with claim 11 further comprising mixing means for mixing fuel and oxidant in said first stage chamber.19. An apparatus in accordance with claim 18, wherein said mixing means comprises at least one first stage mixer wall forming a first stage mixing chamber in fluid communication with said first stage fuel inlet, said first stage oxidant inlet and said first stage fuel/oxidant outlet openings.20. An apparatus in accordance with claim 11 further comprising at least one fuel distribution plenum wall disposed within said first stage chamber enclosing a first stage fuel distribution plenum and forming at least one fuel distribution plenum outlet opening aligned with each of said fuel/oxidant outlet openings.21. An apparatus in accordance with claim 11 further comprising at least one third flow control wall forming a third flow control plenum disposed within said fluid containment vessel proximate said second end wall, said third flow control plenum in fluid communication with said second flow control plenum, and at least one third tubular heat transfer element connecting said second flow control plenum to said third flow control plenum.