Abstract: This Document is a Continuation in Part of U.S. patent application Ser. No. 09/093,029 filed on Jun. 8, 1998, said invention comprising an apparatus for evaporating water in a mixture of water and solids derived from the organic output of a waste water treatment plant. A low cost source of gaseous heat (as the exhaust from a gas turbine driver in combination with/or alternatively from a stand alone combustor) is used for evaporating said water and safe conditioning said evaporated water vapor after being combined with a portion of the exhaust from said gaseous heat source. The solids portion of said organic output from said waste water treatment plant is segregated and safe conditioned separately. This continuation in part filing supplements said basic reference patent filing by defining a specific heat exchange surface configuration for heat exchanger 17 which minimizes radiation heat losses to atmosphere.

Abstract: The invention comprising an apparatus for evaporating water in a mixture of water and solids derived from the organic output from a waste water treatment plant. A low cost source of gaseous heat (as the exhaust from a gas turbine driver and in combination with an auxiliary combustor) is used for evaporating the water and safe conditioning the evaporated water vapor after being combined with the exhaust from the gaseous heat source. The solids portion of the organic output from the waste water treatment plant is segregated and safe conditioned separately.

Abstract: The invention comprising an organic waste fuel combustion and tempering gas flow control system integrated with a gas turbine combined cycle steam generating plant. The gas turbine exhaust, wherein the oxygen content is partially consumed is used to dry and support combustion of an organic fuel high in moisture content after said fuel has been dewatered and pelletized. A portion of the gas turbine exhaust gas stream dries the pelletized waste fuel while a parallel portion of the gas turbine hot gas stream is used to support combustion and furnish oxygen in the ignition zone of the pelletized waste combustor. The drying stream also tempers secondary combustion gas temperature. The two gas streams are combined downstream of the combustion zone. The regenerated combined stream is then utilized in a steam generating section to generate steam.

Abstract: The invention comprises an unfired fluidized bed dryer and sorter. Pressurized fluidizing air is preheated passing through steam heat exchangers. Bed outlet air/vapor temperature is held in a range of 100 F. to 150 F. Smaller/low density solids are removed from the top of the bed and larger/heavier solids are removed from the bottom of the bed after some retention in the bed. Feedstock is fed continuously to the bed. The exhaust air/water vapor from the bed is postheated at least 20 F. before passage through a bag house by addition of steam heated air to the air/vapor stream exhausting from the bed. Moisture content of the effluent solid materials from the bed is controlled by mass flow rate of the fluidizing air and rate of steam flow to the bed air heater.

Abstract: The invention comprising a drying and sorting apparatus for preparation of solid fuel and other solid materials having substantial surface moisture. Ambient air/gas is preheated by indirect heat exchange or other unfired means sufficiently to provide heat needed by the downstream process. The air/gas is then passed up vertically through a bed containing the solid materials, heating and fluidizing them along with the surface moisture. When in a fluidized state, the smaller/lower density particles rise to the top of the bed. At least a portion of the surface moisture on the particles is evaporated. The quantity and temperature of the air/gas flow is sufficient to retain the evaporated surface moisture in the vapor phase. Feedstock of solid materials is added to an intermediate location of the bed. The larger/more dense fluidized particles are removed from bottom location/s of the bed. The smaller/less dense fluidized particles are removed from top location/s of the bed.

Abstract: The invention comprising a drying and sorting apparatus for preparation of solid fuel prior to firing in a combustion furnace. Unsaturated air/gas is passed through a bed containing a mixture of solid fuel and inert material particles, fluidizing them. The unsaturated air/gas is the drying vehicle. When in a fluidized state, the lighter organically derived solid fuel particles separate from the heavier inert material particles. The air/gas is admitted to the bed directionally in a manner which drives the mixture in a retraceable path to outlet points downstream of the point of feedstock entry, the heavier inert material settling at the bottom and the lighter solid fuel particles rising in the bed. Means are provided in the sorter floor for selectively concentrating and directing the solid inert material to the collection point transversely to the direction of particle flotation.

Abstract: The invention comprising a circulating fluidized bed firing system for a steam generator wherein the mass flow ratio for solid materials recirculated to hot gas flow employed to entrain and carry the recirculated solid materials to point/s of separation ranges from 6:1 to 2:1 at the furnace outlet and at rated conditions of the steam generator. Means are provided to cool the recirculated solids upstream and/or after separation of the recirculated solids from the gas stream. Conservative gas velocities for entrainment of solid particles in a range of from 16 to 25 ft./sec. at rated conditions of the steam generator minimize erosion of the coolant filled tubular heat exchange surface disposed in the gas stream upstream of the point of separation of solids from the gas stream.

Abstract: The invention comprises a steam generator having a circulating fluidized bed combustion system whereby there is provision to admit air flow incrementally along the gas path to control combustion rate and firing temperature in a manner to maintain differential temperatures along the gas path. The initial portion of the gas path where combustion is initiated can be held in one temperature range as 1550.degree. F. which is optimum for sulphur retention and the final portion of the combustion zone can be elevated in temperature as to 1800.degree. F. to produce a greater degree of heat transfer through the gas to fluid heat exchange surface downstream of the combustion zone.

Abstract: The invention comprises a dense pack heat exchanger for a steam generator having a circulating fluidized bed combustion system whereby a bed of solid particles comprising fuel and inert material is entrained in the furnace gas stream. Means are provided for collecting high temperature bed solid particles downstream of the furnace. The dense pack heat exchanger directs the hot collected particles down over heat transfer surface, such surface being a portion of the steam generator fluid circuits. Flow is induced by gravity means. The dense compaction of the solid particles around the fluid heat exchange circuits results in high heat transfer rates as the fluid cools the compacted solid material. The heat exchange surface is arranged to facilitate flow of the solid particles through the heat exchanger.

Abstract: The invention comprises an integrated control means, and particularly at partial loads, for a steam generator having a circulating fluidized bed combustion system wherein gas recirculation means is used to supplement combustion air flow to maintain gas velocity in the circulation loop sufficient to entrain and sustain particle mass flow rate at a level required to limit furnace gas temperature to a predetermined value as 1550 F. and wherein gas recirculation mass flow apportions heat transfer from the gas and recirculated particles among the respective portions of the steam generator fluid heat absorption circuits, gas and circulating particle mass flow rates being controlled selectively in a coordinated manner to complement each other in the apportionment of heat transfer optimally among the fluid heat absorption circuits while maintaining furnace gas temperature at a predetermined set point.

Abstract: The invention comprises a drying and sorting apparatus which is integrated with a conventional steam generator for separating organically derived solid fuel from solid inert materials and for removal of moisture from the solid fuel prior to feeding such fuel to a combustor. Low level heat in the steam generator combustion gases, after heat exchange with the steam generator fluid circuits, provides the means for removing moisture from the solid fuel when hot air/gas (unsaturated with respect to moisture) is passed through a bed containing a mixture of solid fuel and waste inert material particles, fluidizing them. When in a fluidized state the lighter organically derived solid fuel particles separate from the heavier inert material particles.

Abstract: The invention comprises a steam generator fluidized bed which recirculates through a major portion of the normal gas to fluid heat transfer circuits. Solid bed material is separated, collected and recirculated. Bed temperatures are limited by regulation of density of bed inert material to inhibit the radiant aspects of combustion. Gas recirculation is used to supplement air flow to achieve higher than entrainment bed gas velocity in the fuel ignition and reaction zone. Fuel ignition and reaction are controlled by limiting the amount of atmospheric air flow to the circulating fuel rich bed mixture to regulate extent of propagation of the ignition and reaction zone into the initial portion of the circulating bed loop, starting from the point of highest gas pressure.

Abstract: The invention comprises a steam generator having a migrating fluidized bed combustor system. The bottom, head end of the bed incorporates a support floor system through which air is admitted tangential to the floor in a manner which causes the bed to migrate in a retraceable track. Tangential admission of air cools the floor and inhibits reverse flow down through the floor when the bed is slumped. Particle entrainment velocities are developed at mid-point in the bed. Tangential entrainment gas flow assures uniform distribution of combustibles and inert material throughout the lower bubbling bed and furnace area above the mid-point. Platens in the furnace zone straighten gas flow for gravity separation of particulate at the outlet of heat transfer surface above the furnace.

Abstract: The invention comprises a steam generator having a circulating fluidized bed firing system. Particles of fuel and solid inert material are recirculated in a furnace wherein gas velocities are maintained at levels sufficient to entrain the fuel and inert material particles in the gas stream. A plenum is provided at the furnace outlet wherein gas velocity drops below entrainment level and the particles are directed to a collection hopper for recycle. The gas is withdrawn from the plenum through ducting in a manner to assure uniform gas distribution through the plenum. High gas velocity through the ducting improves heat transfer in the fluid cooled enclosure surface where such surface is incorporated into the ducting. The ducting connect to the downstream gas path.

Abstract: The invention provides a means for more effectively adapting fluidized bed combustors for retrofit of existing boilers for burning of low grade inexpensive solid fuels. The operating discharge gas from a fluidized bed combustor is substantially lower in temperature from what exists at the furnace gas outlet of a conventional steam generator. Thus, outlet gas from fluidized bed combustors needs to be placed in the downstream gas path differently from conventional practice. The external combustors of the present invention permit placement of hot gas in the steam generator gas path where it can be effectively utilized. The invention also teaches how new steam generators can be configured advantageously to accommodate multiple fluidized bed combustors particularly as pertains to larger capacity steam generators in the 200 MW electrical and larger range.