Claims
- 1. A steam generator having a feedwater inlet and steam outlet and coolant filled heat absorption circuits disposed in between, a vertical up flow furnace, walls for said furnace including a first portion of said heat absorption circuits, a combustion system contained by said furnace comprising a first ignition and reaction zone at the bottom of said furnace, means for continuously feeding solid fuel and air to said first zone sustaining combustion and generating hot flue gas, a second zone above said bottom of said furnace including means for admission of secondary gas to said furnace, means for overflowing said hot flue gas and said solid fuel from said first zone along with recycled solids up into said second zone to form a combined gas stream, means to maintain velocity of the combined gas stream in and above said second zone sufficient for entraining in said combined gas stream a substantial portion of said overflowed solid fuel and recycled solids, additional portions of said heat absorption circuits disposed horizontally at the outlet of said furnace and provided with an enclosure interconnected with said furnace walls, means causing the volumetric relationship of said enclosure and gas temperature to drop across components of said additional portions for reducing velocity of said combined gas stream between said components below entrainment level for part of said entrained solids permitting said solids part to settle in a fluidized state, means for separation of said solids remaining in said main path of said combined gas stream at a downstream location, means for continuously draining said settled solids port away from the main path of said combined gas stream, means to recycle said drained away settled solids part and said separated remaining solids between said first and second zones, and means to exhaust said main path of said combined gas stream after said remaining solids separation.
- 2. A steam generator as recited in claim 1 and including means for individual control of mass flow rate of said recycled solids and said solid fuel and said air and said secondary gas to said furnace in proportions to maintain a relatively constant medium furnace gas temperature and a substantially lower gas temperature at said point of separation of said remaining solids.
- 3. A steam generator as recited in claim 1 and wherein at least a first portion of said secondary gas comprises air, including a fan or blower adapted to deliver said air to said secondary gas admission means.
- 4. A steam generator as recited in claim 1, said interconnected enclosure for said additional portions of said heat absorption circuits and said related combined gas stream being configured as an inverted U, said combined gas stream entering said interconnected enclosure in an upflow direction and passing through a first part of said additional portions of said heat absorption circuits, said combined gas stream then reversing direction in a U path and flowing downward through the remaining part of said additional portions of said heat absorption circuits, conduit means for flowing any of said settled solid portion in said upflow combined gas stream to a lower level in said downflow combined gas stream.
- 5. A steam generator as recited in claim 2 and wherein a second portion of said secondary gas comprises a portion of said combined gas after separation of said remaining solids, including a fan or blower adapted to recirculate said portion of said combined gas after separation of said remaining solids to said secondary gas admission means, and means to vary the proportions of said air and said recirculated combined gas supplied to said secondary gas admission means.
- 6. A steam generator having a feedwater inlet and steam outlet and coolant filled heat absorption circuits disposed in between, a furnace, an enclosure for said furnace at least partially cooled by a portion of said heat absorption circuits and adapted to contain a combustion system comprising a first ignition and reaction zone at the bottom, means for feeding solid fuel and air continuously to said first zone individually and at controlled flow rates to sustain combustion and to generate hot flue gas, a second zone including means for admission of secondary gas above said bottom of said furnace at a controlled flow rate, said hot flue gas and said solid fuel material overflowing from said first zone along with recycled solids up into said second zone to form a combined gas stream, said flue gas and said secondary gas maintaining downstream combined gas velocity sufficient to entrain at least a significant portion of said fuel and said recycled solids in said combined gas stream, additional portions of said coolant heat absorption circuits disposed at the outlet of said furnace, an extension of said furnace enclosure for housing said additional portions, means for separating said solids entrained in said downstream combined gas stream intermediately and/or at the outlet of said additional portions of said heat absorption circuits, means for collecting and recycling said separated solid particles to said second zone combined gas stream at a controlled flow rate and to increase said flow rate of said separated particles in response to high temperature of said furnace combined gas and vice versa, said means for feeding air and said means for admitting secondary gas to said furnace to increase said downstream combined gas flow rate in response to low temperature of said combined gas at a point intermediately or at the outlet of said additional portions and vice versa, said additional portions of said heat absorption circuits and mass flow rates of said entrained solid particles and said downstream combined gas being proportioned to maintain said second zone furnace gas temperature at a medium level as 1550F while maintaining said combined gas temperature at said outlet of said additional portions at a substantially lower level as 650F.
- 7. A steam generator as recited in claim 6 and wherein at least a first portion of said secondary gas comprises air, including a fan or blower adapted to deliver said air to said secondary gas admission means.
- 8. A steam generator as recited in claim 7 and wherein a second portion of said secondary gas comprises a portion of said combined gas after separation of said solids, including a fan or blower to recirculate said combined gas portion after solids separation to said gas admission means, and means to vary the proportions of said air and said recirculated combined gas supplied to said secondary gas admission means responsive to excess air measurement in said combined gas stream at a downstream location.
Parent Case Info
This invention is a continuation-in-part to U.S. Pat. Application Ser. No. 06/371,528 filed 4/26/82
US Referenced Citations (4)
Foreign Referenced Citations (1)
Number |
Date |
Country |
56-68708 |
Jun 1981 |
JPX |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
371528 |
Apr 1982 |
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