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WO1996024810A1 - Systeme de manipulation et de transport de matieres particulaires du type cendres chaudes - Google Patents

Systeme de manipulation et de transport de matieres particulaires du type cendres chaudes Download PDF

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Publication number
WO1996024810A1
WO1996024810A1 PCT/US1996/001317 US9601317W WO9624810A1 WO 1996024810 A1 WO1996024810 A1 WO 1996024810A1 US 9601317 W US9601317 W US 9601317W WO 9624810 A1 WO9624810 A1 WO 9624810A1
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WO
WIPO (PCT)
Prior art keywords
ash
particles
boiler
outlet
recited
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/US1996/001317
Other languages
English (en)
Inventor
William J. Salesky
Andrew G. Hay
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Stamet Inc
Original Assignee
Stamet Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Stamet Inc filed Critical Stamet Inc
Priority to AU52954/96A priority Critical patent/AU5295496A/en
Publication of WO1996024810A1 publication Critical patent/WO1996024810A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
    • F23C10/00—Fluidised bed combustion apparatus
    • F23C10/18—Details; Accessories
    • F23C10/28—Control devices specially adapted for fluidised bed, combustion apparatus
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
    • F23C10/00—Fluidised bed combustion apparatus
    • F23C10/18—Details; Accessories
    • F23C10/24—Devices for removal of material from the bed
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D15/00—Handling or treating discharged material; Supports or receiving chambers therefor
    • F27D15/02—Cooling
    • F27D15/0206—Cooling with means to convey the charge
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D3/00—Charging; Discharging; Manipulation of charge
    • F27D3/0033—Charging; Discharging; Manipulation of charge charging of particulate material
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J2900/00—Special arrangements for conducting or purifying combustion fumes; Treatment of fumes or ashes
    • F23J2900/01002—Cooling of ashes from the combustion chamber by indirect heat exchangers

Definitions

  • the present invention relates to systems and methods for transporting and cooling hot ash or other particulate material and, in particular embodiments, to apparatus and methods for handling and transporting hot ash from a furnace, combustor or boiler, such as a fluid bed combustor. Further embodiments relate to boiler, combustor or furnace systems employing a hot ash transporting and cooling sub-system. Yet further embodiments relate to a method of controlling the bed of a fluidized bed reactor or combustor by controlling the rate of removal of hot ash and/or other particulate material from the bed.
  • Modem solid fuel burning power production facilities produce large amounts of ash and particulate waste.
  • a typical power plant boiler, combustor (or furnace) produces hundreds of thousands of tons of ash and particulate waste. This ash and particulate waste must be transported from the furnace and cooled, before it can be stored or otherwise processed.
  • a typical coal fired power production plant produces several types of ash.
  • Fly ash, economizer ash, and bottom ash are typical examples of the ash produced.
  • the fly ash is typically very fine and is captured in a bag house, economizer, or other device so not to be vented in the plant stack.
  • Bottom ash is heavier and is typically removed from the lowest point in the boiler, combustor or furnace. Although the amount of bottom ash produced, as compared to fly ash, is a function of the fuel burned, for coal it typically ranges 40 to 60% or more of the total ash produced.
  • boilers For coal fired power production facilities, several designs of boilers have been used (including for example, pulverized fuel, traveling grate or the like), each having a demand for ash handling and cooling. These boilers are typically water tube type boilers for which fuel can be introduced in a myriad of ways; e.g., top fired, comer fired, bottom fired, front fired, etc. Bottom ash typically settles on a grate and then is transported or drained to an outlet from the boiler. It is important that ash removal be controlled and maintained frequently on a continuous basis.
  • An advancement on conventional boiler technology mentioned above is the development of a fluidized bed combustor. In this system, fuel is introduced into a reaction chamber in which air is continuously circulating to entrain and fluidize the fuel.
  • the circulation encourages the fuel to bum completely, potentially in the presence of finely divided limestone (or other substantially inert materials) to act as a getter for sulfur released in the coal combustion.
  • bottom ash forms the "bed" in the fluidized bed thereby supporting the continuous combustion reaction.
  • Fluidized bed combustors typically operate at pressures slightly to well above atmospheric pressure. To permit the fluidized bed to run continuously without interruption, bed level must be maintained within specific limits. Since fuel is being continuously added, the ash must be continuously withdrawn, so as to maintain the bed level within the necessary limits. Since the fluidized bed is above atmospheric pressure, ash removal must be done so as not to release the pressure from the fluidized bed. Therefore, accurate continuous control of ash discharge is essential to effective operation of a fluidized bed combustor.
  • typical fluidized bed combustors operate most efficiently when the bed is relgulated and maintained within certain predefined volume limits (determined by the size and design of the combustor and the rate of fuel input).
  • certain predefined volume limits determined by the size and design of the combustor and the rate of fuel input.
  • output rates for removing spent bed material
  • combustor to operate most efficiently (to produce a maximum heat output per volume of fuel input) and cleanly (to produce a minimum of harmful polutants per volume of fuel input).
  • Various prior methods and devices for removing hot ash and particulate material from a furnace, combustor or boiler have a tendency of providing inconsistent removal rates and/or deteriorate over a relatively short period of use.
  • Fluidized bed boiler bottom ash is typically between 1500°F and 1900°F, and must be cooled, for example, to less than 500°F to be stored in an ash holding silo. These lower temperatures also minimize the risk of further combustion of unbumed carbon contained within the material being transported and stored.
  • this demand is associated with the ash production rate of the combustor and, thus, the rate at which fuel is supplied to and combusted by the combustor, as well as the combustor design and size.
  • typical fluidized bed combustors require an ash bed containing a prescribed volume of ash. The removal of ash must closely match the production of ash to maintain the prescribed ash bed level, assuring proper bed volume.
  • the equipment and system employed for controlling the combustor of a fluidized bed combustor, by controlling the transporting (or transportating and cooling) of ash from the combustor is capable of providing a highly regulatable flow rate to match the ash removal demand of the combustor.
  • the ash removal rate is preferably readily adjustable to accomodate different fuel input rates.
  • combustor ash transporting and cooling equipment must be capable of withstanding the elevated temperatures of boiler ash and the temperature differential between combustor ash and coolant (e.g., cooling water) typically employed to cool the ash.
  • coolant e.g., cooling water
  • the equipment must be capable of sustaining ash flow rates as high as 50,000 to 300,000 Ibs/hr per combustor (and possibly higher for new generation combustor designs).
  • the equipment must also be capable of handling ash and other particulates of varying sizes including hemp, iron, stones, refractory mining tool fragments, etc.
  • the equipment must be capable of reliable operation over a long operational life.
  • the ash may be highly abrasive.
  • Coal ash is principally composed of silica, alumina oxide, and other minerals.
  • the relative concentration of silica and alumina typically will be a total of 40 weight percent or more.
  • these concentrations of silica and alumina can lead to significantly shortened equipment life, due to accelerated abrasion and erosion, as compared to handling of "low" ash coals for which such problems are significantly less.
  • bottom ash handling in traditional water tube boilers ranges from traveling grates to remove bottom ash, to gravity flow systems, to assorted conveyor systems.
  • Bottom ash cooling systems range from direct water flood cooling of ash to assorted indirect cooling methods.
  • ash In a fluidized bed cooler, ash is introduced between a series of fluid filled cooling baffles while entrained in a stream of air.
  • the main problem with this system is that contaminant materials such as stones fall from the fluidized stream of ash and settle on the bottom of the cooler.
  • these coolers must be used in association with rotary valves mentioned above.
  • Rotary valves typically feature a star shaped element which rotates within the valve body to permit control of ash discharge from atmospheric or elevated pressures. In low ash fuel applications these valves operate for years without significant problem.
  • liquid-cooled screw feeder devices typically include an elongated, helical blade which is rotatable within an elongated tube. Ash from a boiler is fed from the boiler as drawn (e.g., by gravity) into the elongated tube and accumulates within the helical winding of the blade. Rotation of the helical blade draws the ash along the length of the tube, away from the boiler. Coolant (e.g., water) is typically either sprayed directly on the ash or is pumped through cooling ducts or tubes within or along the blade.
  • Coolant e.g., water
  • the flow rate provided by a screw feeder is dependent upon the feeder size, blade pitch, and the blade rotation rate.
  • the resulting flow rate is regulated or metered.
  • the flow rate can thereby be adjusted to accommodate the variable demand for removal of boiler ash.
  • This regulatable flow rate has drawn those skilled in the art to employ screw feeder technology for boiler ash transportation and cooling systems.
  • liquid-cooled screw feeders tend to be relatively large, bulky and expensive devices, especially when designed to handle the high volume ash removal demands of modem power generation system boilers and combustors, such as modem fluid bed combustor systems.
  • screw feeders typically have a tendency to jam from time to time, resulting in a partial or complete stoppage of the ash flow.
  • the removal of ash from a higher pressure environment (even if just a few pounds square inch above atmospheric pressure), as is the case in most fluidized bed combustors, tends to exacerbate the jamming and clogging problems of screw feeders and can also cause sporatic changes in the ash removal rate and, thus, the efficiency of the combustor system.
  • screw feeders typically employ relatively expensive components, such as large helical blades and rotary blade supports, which are subject to wear and possible breakage during operation. Additionally, the carrying capacity of such feeders is dependent upon the size of the blade and the speed of blade rotation, each of which are typically limited, for practical purposes, by economic, space and power constraints. Screw feeders also tend to have limited cooling capabilities. The effectiveness of the coolant is somewhat diminished by the packing of ash material within the confines of the helical blade winding and the elongated tube. In many applications screw coolers have performed somewhat effectively.
  • Rotary drum coolers are especially effective for handling abrasive materials at elevated temperatures.
  • a rotary drum cooler slow rolling action rather than shearing, as compared with a screw coolers, results in a significantly lower rate of abrasive wear.
  • a rotary drum cooler can function in several ways; direct cooling, indirect cooling, or combination of direct and indirect cooling.
  • Indirect cooling in a rotary drum cooler involves a liquid coolant being sprayed on the outside of the drum cooler and never coming in contact with the media being cooled. Heat is removed via heat transfer through the shell (or drum wall) of the cooler into the liquid coolant.
  • Direct cooling involves coolant spray directly onto the medium to be cooled.
  • the phase transformation from a liquid to a vapor removes heat from the solid being cooled. This method is highly efficient and effective. In this application there must be a method to handle the vapor that is produced.
  • Preferred embodiments of the present invention relates to apparatus and methods for controlling a fluidized bed combustor by controlling the ash removal rate from the combustor and for transporting boiler ash or other particulate material at a metered rate and for cooling the ash or particulates with improved efficiency with respect to typical screw feeder and other systems.
  • Preferred embodiments employ a moving wall type (or rotary disk type) particulate material metering apparatus coupled in ash-flow communication with the bed of a fluidized bed combustor for providing a highly regulatable and efficient removal of ash and particulates from the combustor bed.
  • the rate of motion of the moving wall is regulated to control the ash removal rate to substantially match the ash production rate of the combustor, to maintain a substantially constant bed volume within the combustor.
  • rotary drum cooling technology is used in conjunction with moving wall type (or rotary disk type) particulate material metering apparatus.
  • a system includes (or is operable with) a combustor, such as a fluid bed combustor for a power plant.
  • the combustor requires an ash bed in which a prescribed level or volume of ash is maintained. As ash builds up in the bed toward the upper limit of the prescribed volume, ash is discharged from a boiler ash outlet.
  • a particulate material metering and transporting apparatus is coupled to the boiler ash outlet to pump or remove ash away from the combustor.
  • the particulate material metering apparatus is controlled to continuously discharge ash away from the combustor at a rate consistent with the ash removal needs of the combustor.
  • the particulate material metering apparatus comprises a pair of moving walls (such a the walls of a pair of rotating disks), between which ash or other particles bridge and are thereby driven at a rate dependent upon the rate of the wall motion.
  • the particulate material metering apparatus has an outlet coupled to the inlet end of a rotary drum cooler. Ash and particulates driven from the boiler at a rate consistent with the ash removal demand of the combustor, enter the rotary drum cooler and are cooled by direct water spray at a relatively high rate and efficiency. Steam generated within the rotary drum cooler may be recycled back into the fluidized bed combustor. Cooled solids exit the rotary drum cooler through a solids outlet.
  • the movable wall type particulate material metering apparatus (such as a rotary disk pump) provides a highly accurate, regulatable drive system, capable of regulating the ash output of the combustor and, thus, regulating the efficiency of the combustor.
  • the rotary drum cooler provides a highly efficient ash cooling action which is capable of recycling some energy removed from the ash as the ash is cooled.
  • the overall system offers the ability to efficiently remove ash from the combustor at a rate regulatable to meet the ash removal needs for maximum combustor efficiency, as well to efficiently remove heat from the boiler ash and recycle some energy therefrom.
  • these capabilities are provided without the complex structures and other disadvantages associated with screw feeder and other technologies.
  • FIGURE 1 is a schematic representation of a prior art boiler and boiler ash transporting and cooling system.
  • FIGURE 2 is a schematic representation of a boiler or combustor and ash transporting and cooling system according to a preferred embodiment of the present invention.
  • FIGURE 3 is a side cross-sectional view of a particulate transporting and metering apparatus 36 of the FIGURE 2 embodiment.
  • FIGURE 4 is a top cross-sectional view of a particulate transporting and metering apparatus 36 of the FIGURE 2 embodiment.
  • FIGURE 5 is side view of a rotary drum cooler 42 of the FIGURE 2 embodiment.
  • FIGURE 6 is radial cross-sectional view of a rotary drum cooler 42 of the FIGURE 2 embodiment.
  • FIGURE 7 is partial perspective view of the inlet end of a rotary drum cooler 42 of the FIGURE 2 embodiment.
  • FIGURE 8 is a partial perspective view of the outlet end of a rotary drum cooler 42 of the FIGURE 2 embodiment.
  • the present invention relates to a fluidized bed apparatus and methods of controlling the same and, in particular embodiments, systems and methods for controlling a fluidized bed combustor apparatus by controlling the ash removal rate thereof and for handling and transporting hot ash or other particulate material and, in further embodiments, including apparatus and methods for handling and transporting hot ash from a boiler, combustor or furnace, such as a fluid bed combustor. While preferred embodiments of the present invention relate to power plant boiler or combustor systems and components thereof for transporting and cooling ash, it will be understood that further embodiments of the invention may be employed for transporting and cooling other materials.
  • Fluidized bed reactors have been used to provide and control chemical reaction processes for the production or treatment of certain materials, such as for the thermal oxidation of materials.
  • a fluidized bed of materials is constantly being renewed, similar to the renewal of the ash and particulate bed in a fluidized bed combustor, such that there is a need to constantly remove material from the bed and control the bed volume, similar to the need to constantly remove ash and particulates to control the volume of the bed in a fluidized bed combustor.
  • embodiments of the invention are described below in the context of a fluidized bed combustor. It will be understood, however, that the concepts and appartus discussed below are applicable to other fluidized bed systems, including fluidized bed reactors.
  • liquid-cooled screw feeders have and are presently used in various power plant boiler systems for transporting and cooling hot ash from the boiler.
  • a generalized representation of such a system is shown in prior art Figure 1 , wherein a boiler 10 is provided with a fuel inlet 12 and an ash outlet 14.
  • the boiler 10 may be, for example, a fluid bed boiler for combustion of high sulphur coals to generate steam for use in electrical power generation.
  • the boiler 10 may be any other suitable type boiler for combustion of any suitable solid fuels, including, but not limited to, anthracite silt, culm, gob, high sulphur bituminous, anthracite coal, lignite, bituminous coal, automobile tires, wood chips, paper sludge, coke, fuel oil, natural or refined gas, biomass or the like.
  • any suitable solid fuels including, but not limited to, anthracite silt, culm, gob, high sulphur bituminous, anthracite coal, lignite, bituminous coal, automobile tires, wood chips, paper sludge, coke, fuel oil, natural or refined gas, biomass or the like.
  • a water-cooled screw feeder 16 is coupled at one end to the outlet 14, to receive ash and other particulates from the ash bed of the boiler 10.
  • the screw feeder 16 includes an elongated helical blade 18 supported for rotation about an axis 20 within a hollow tube structure 22.
  • the helical blade 18 is rotatably driven by a motor 24.
  • Coolant water is provided to coolant channels (not shown) in the blade 18 and/or the tube structure 22, via a coolant pump 26.
  • Rotation of the helical blade 18 draws ash received from the boiler outlet 14 along the length of the tube structure 22, away from the boiler and toward a tube outlet 28. As the ash is drawn along the length of the tube structure 22, coolant removes heat from the ash, thereby reducing the ash temperature.
  • the rate of rotation of the helical blade 18, and, thus, the rate at which ash is removed from the boiler, is controlled by a motor control system 30.
  • the motor control system 30 may receive control signals from sensors in the boiler, to control the motor speed in accordance with the ash removal demand of the boiler.
  • pressure sensors may be used to determine the pressure difference across the ash bed. If the pressure drop across the ash bed is above a preset range of values, the ash bed may be too high and thick, requiring a higher ash removal rate. In this case, a signal is provided to the motor control 30 to increase the motor speed and, thereby, increase the rotational speed of the blade 18 to increase the ash removal rate. If the pressure drop across the ash bed is below a preset range of values, a signal is provided to the motor control 30 to reduce the motor speed and, thereby, reduce the ash removal rate.
  • the tube outlet 28 may be coupled to a further ash transportation or storage unit, generally represented by box 32. Because the unit 32 is located remote from the boiler 10 and downstream of the initial cooling stage (i.e., the water-cooled screw feeder stage), the rate of ash flow through unit 30 need not be dependent on the ash removal demands of the boiler. In addition, the unit 30 need not be constructed to accommodate the high temperatures of the ash prior to the initial cooling stage.
  • the initial cooling stage i.e., the water-cooled screw feeder stage
  • screw feeder type device as shown in Figure 1 can provide a somewhat regulatable ash removal rate (as is required in modem boiler designs), the cooling and operation efficiencies of typical screw feeders are limited. Moreover, additional problems relating to cost, size, cooling effectiveness, operational life, maintenance costs, operational down time, durability, and operation malfunctions, as discussed above, are associated with typical screw feeder ash removal systems. Furthermore, screw feeders tend to be jammed when transporting from a higher pressure environment to a lower pressure environment, such as when transporting ash out of a fluidized bed combustor (which typically tend to be at least a few pounds per square inch above atmospheric pressure) into an atmospheric pressure environment.
  • embodiments of the present invention address these needs and, yet, are not reliant on screw feeder technology.
  • Preferred embodiments employ a moveable wall (or rotary disk) type particulate transporting apparatus which is capable of operating accross a pressure differential and is capable of providing a highly regulatable flow rate.
  • Further preferred embodiments employ rotary drum cooling technology in conjunction with the moveable wall (or rotary disk) apparatus which is, generally, less structurally complex, less costly and more durable than typical screw feeder devices.
  • a system according to a first preferred embodiment of the invention is generally represented by the drawing of Figure 2, wherein a combustor or boiler 10 has an outlet 14 coupled to the inlet 34 of a particulate pump device 36.
  • the combustor 10 is a fluidized bed combustor which operates, as discussed above, with a bed formed of ash and particulate material.
  • the bed is constantly being renewed, in that new ash is constantly being formed and added to the bed by the combustion of fuel, while bed ash is constantly being removed such that the overall bed volume is maintained within a predetermined range most suitable for the combustor and the desired combustor efficiency.
  • the outlet 38 of the pump 36 is coupled to the inlet end 40 of a rotary drum cooler 42.
  • the rotary drum cooler 42 is supported by a frame 44.
  • the outlet end 46 of the rotary drum cooler has a steam (or gas) outlet 48 and a solids outlet 50.
  • the solids outlet 50 is coupled to the further ash transportation or storage unit 32.
  • a motive device 52 (such as a motor, chain or belt drive, or other suitable means for providing or transfemng rotational motion) is coupled to drive the pump 36.
  • the motive device 52 may be controlled by a controller unit 30 in a manner similar to that described above with respect to the controller unit 30 in Figure 1.
  • Alternative means of determining the actual (or approximate) bed volume or thickness may be employed by the controller 30.
  • the pump 36 comprises a rotary disk particulate pump system, such as described in U.S. Patent No. 4,516,674, titled “Method and Apparatus for Conveying and Metering Solid Material", issued May 14, 1985; U.S. Patent No. 4,988,239, titled “Multiple Choke Apparatus for Transporting and Metering Particulate Material", issued January 29, 1991; U.S. Patent No. 5,051,041, titled “Multiple Choke Apparatus for Transporting and Metering Particulate Material", issue September 24, 1991; U.S. Patent No. 5,355,993, titled "Grooved Disc Drive
  • the pump 36 comprises a pair of opposed movable walls (such as disk walls as described in the above-referenced patents and applications).
  • alternative embodiments may employ other suitable particulate metering devices capable of withstanding the temperatures associated with boiler ash. Simplified representations of a preferred rotary disk pump 36 are shown in Figures 3 and 4.
  • the rotary disk pump 36 comprises a pair of disk 54 and 56 coupled together by a central hub 58.
  • the disks and hub are supported within a housing 60 for rotation about the axis of a central axle 62.
  • the disks 54 and 56 and hub 58 are composed of a single, unitary double-disk structure.
  • the disks 54 and 56 are spaced from each other to define a transport channel 64 therebetween.
  • a stationary wall 66 (which may be a wall of the housing 60 or a separate wall located within the housing 60) is arranged along the length of the transport channel 64 to define the outer peripheral wall of the channel.
  • the transport channel 64 is, therefore, bordered by the inward facing surfaces of the disks 54 and 56, the outer peripheral surface of the hub 58 and the inner peripheral surface of the stationary wall 66.
  • these surfaces are formed of a suitable material (and/or are treated) for accommodating the temperatures associated with combustor or boiler ash.
  • these surfaces may be formed of suitable metals (e.g., stainless steel), ceramics, refractory materials, ceramic coated metals or the like, for accommodating the elevated temperatures of combustor or boiler ash.
  • the housing 60 is provided with an inlet 68 and outlet 70, each of which are in particulate flow communication with the transport channel 64.
  • the inlet 68 is coupled in particulate flow communication with the boiler outlet 14.
  • the pump housing outlet 70 is coupled in flow communication with the inlet end 40 of the rotary drum cooler 42.
  • the disks 54 and 56 are coupled through the hub 58 to the axle 62 for rotation with the axle.
  • the axle, disks and hub are supported within the housing by bearing structures 72.
  • the motive device 52 is operatively coupled to the axle 62 to impart a rotational drive force to the axle. Rotation of the axle 62 results in rotation of the disks 54 and 56 and hub 58 about the axis of the axle.
  • ash and other particulate material 74 from the combustor or boiler outlet 14 enters the transport channel 64.
  • the disks 54 and 56 rotate, the ash and other particulates 74 bridge between the disk surfaces and are driven by the disks toward the outlet 70 in the manner described in the above-referenced patents and applications assigned or licensed to the present assignee.
  • the rate at which the pump 36 drives ash and particulates away from the boiler is dependent upon the rotation speed of the disks 54 and 56.
  • This rotation speed may be controlled and regulated by a suitable control unit 30 in a manner similar to the manner in which the rotation of screw feeder blade is regulated, as described above.
  • the pump 36 is not as likely to jam or clog due to pumping across a pressure differential.
  • the pump 36 is not as susceptable to errosion deterioration (and alterations in ash flow rate caused thereby) as typical screw feeder type systems.
  • the rotation speed of the disks 54 and 56 can be readily regulated and quickly altered to meet the ash removal demands of the combustor or boiler.
  • a movable wall (or rotary disk) type pump as described in the above-referenced patents and applications incorporated by reference may be included in pump 36.
  • one or both disks 54 and 56 may be provided with a plurality of grooves, ridges, or other discontinuities on the disk surface coextensive with the transport channel 64, as described in the above-referenced '993 patent (incorporated herein by reference).
  • various pump inlet improvements as described in the above- referenced '173 and '314 applications (incorporated herein by reference), may be employed with pump 36.
  • the use of a single moving element greatly simplifies the task of transporting the boiler ash at its elevated temperatures. That is, the characteristic thermal expansion and contraction of materials can be more readily accommodated in a system employing a minimal number of moving parts in contact with hot ash.
  • the moving parts which must be in contact with the combustor ash would exhibit thermal expansion and contraction and would, thus require mounting tolerances to allow for such thermal expansion and contraction without adversely affecting the motion of the parts.
  • a rotary disk pump as described above is a preferred particulate driving sub-system of the overall transporting and cooling system.
  • additional embodiments may employ other suitable regulated drive devices for driving the ash and particulate material away from the combustor and into the rotary drum cooler at a m ⁇ tered rate.
  • the pump outlet 70 is coupled in flow communication with the inlet end 40 of the rotary drum cooler 42.
  • combustor ash and particulates may be driven away from the combustor and into the rotary drum cooler at a rate sufficient to accommodate the ash removal demands of the combustor.
  • the combustor ash can then be subjected to the highly efficient cooling action of the rotary drum cooler and eventually discharged from the rotary drum cooler into a post- cooling transportation or storage unit 32.
  • FIG. 5 A simplified diagram of a rotary drum cooler 42 is shown in Figure 5.
  • the rotary drum cooler comprises an elongated cylindrical drum
  • the length and diameter dimensions of the drum are preferably chosen based upon the flow rate and cooling rate demands of the system.
  • a system designed to accommodate 15,000 Ibs/hr (7.5 tons/hr) of ash may employ a drum having a length of 12 feet and a diameter of 4 feet.
  • the inlet end 40 of the drum has an opening in flow communication with the hollow drum interior.
  • the drum 74 is supported by a frame 44 with the drum axis 76 arranged at an angle, such that the inlet end 40 of the drum is at a higher elevation than the outlet end 46 of the drum.
  • the drum 74 is supported on the frame 44 by any suitable supporting structure which allows the drum to rotate about its axis 76.
  • such support structure includes a plurality of rollers 78 mounted for rotation on angled frame members 80.
  • the rollers 78 are positioned to engage raised roller races 82 and 84 provided on the outer peripheral surface of the drum 74.
  • a motive device such as a motor 86 is provided for rotatably driving the drum 74.
  • the illustrated motor 86 is mounted to the frame and includes a motor gear 88 positioned to mesh with a sprocket 90 disposed about the peripheral surface of the drum.
  • suitable motive devices including, but not limited to, belt drives, chain drives, drive rollers or the like
  • the rotary drum cooler 42 is coupled to a liquid coolant pump system 92 for supplying liquid coolant (such as water or other suitable coolant) to spray nozzles located within the drum interior (direct cooling) and/or coolant channels or tubes indirect located in the drum interior, along the drum exterior and/or within the walls of the drum.
  • liquid coolant such as water or other suitable coolant
  • An example of a spray nozzle 94 located within the drum interior is shown in Figure 5 so as to uniformly direct coolant on to the ash.
  • first coolant ducts or tubes 96 located along the outer peripheral surface of the drum, second coolant ducts or tubes 98 located within the drum wall and third coolant ducts or tubes 100 located within the drum interior.
  • the interior drum wall is provided with a spiral channel along its length, as generally indicated in broken lines 102 in Figure 5.
  • the inlet end 40 of the drum (best shown in Figure 7) has an end cap 104 which does not rotate with the body of the drum 74.
  • the outlet end 46 of the drum (best shown in Figure 8) has an end cap 106 which does not rotate with the body of the drum 74.
  • suitable rotary seals are provided between the end caps 104, 106 and the body of the drum 74.
  • the end cap 104 defines an inlet opening 108 which is coupled to the outlet 70 of the pump 36, as discussed above.
  • a coupling joint such as (but not limited to) an expansion joint or a flexible, bellows-like sleeve (not shown), is employed for coupling the pump outlet 70 to the drum inlet opening 108.
  • the end cap 106 defines two outlet openings 48 and 50.
  • the outlet opening 50 is located at the lower-most portion of the end cap 106, in alignment with the lower extent of the drum interior.
  • the outlet opening 48 is located vertically above the opening 50.
  • the outlet opening 50 defines a solids outlet for allowing cooled ash and particulates to exit the rotary drum.
  • the outlet opening 48 defines a steam or gas outlet for allowing steam or gas to exit the rotary drum.
  • boiler ash and particulate material is metered out and pumped away from the combustor or boiler by the rotary disk pump 36 at a rate consistent with the ash removal demand of the boiler.
  • the rotary disk pump 36 may be driven by a suitable motive device 24 (such as a motor or the like) which is controlled by a controller 30.
  • the controller 30 controls the motor speed based on the ash removal demand of the combustor or boiler. This demand may be sensed by, for example, sensing the fuel intake rate of the boiler or the pressure differential across the boiler ash bed. Other suitable procedures for determining or sensing the ash removal needs of the boiler may be employed in alternative embodiments.
  • the ash and particulate material is driven into the inlet opening 108 of the rotary drum by the pump 36.
  • the motor 86 drives the drum 74 in a rotary motion about the drum axis 76. This motion causes the ash and particulates to be drawn around the inner peripheral drum wall and to roll about within the drum.
  • the spiral channel 102 in the inner peripheral surface of the drum wall assists this action and also tends to drive the ash and particulates toward the outlet end 46 of the drum.
  • the inclined angle of the drum acts to direct the ash and particulates toward the outlet end 46. This inclination angle may be %" slope per foot length of the cooler. Cooled ash and particulates are released through the outlet opening 50.
  • the tumbling and rolling of the ash releases heat into the drum interior and through the drum walls.
  • the cooling rate can be increased by pumping a coolant liquid through coolant channels (e.g., channels or tubes 96, 98 and/or 100) in or adjacent the drum wall (in heat flow communication with the drum wall or drum interior).
  • coolant is sprayed within the drum interior, to directly contact the ash. This causes the coolant to be vaporized within the drum interior and cool the ash at a relatively high rate.
  • the steam or vaporized coolant carries heat from the ash and is released through the gas outlet opening 48.
  • Further preferred embodiments may employ both direct and indirect cooling functions, as discussed above.
  • the coolant may be plant cooling service water or condensate, in which case heat lost from the ash is retained in the overall plant thermal cycle.
  • steam released from outlet opening 50 may be recycled to the boiler steam supply.
  • the interior of the drum and pump structures are maintained at a pressure at or slightly below that of the ambient atmosphere outside of the pump and drum.
  • Subatmospheric pressure helps reduce the seepage of ash dust from the system into the ambient environment.
  • the lower pressure may be tapped from a low pressure volume of the boiler plant system, such as from the fluidized bed system of a fluid bed boiler.
  • the rotary disk pump 36 provides a highly accurate, regulatable drive system which can be regulated to closely match the varying ash removal demands of power plant boilers.
  • the rotary disk pump 36 can, in effect, control the efficiency of a fluidized bed combustor, by controlling the volume of the bed within the combustor.
  • the rotary drum cooler 42 provides a highly efficient ash cooling action which readily lends itself to recycling energy removed from the ash as the ash is cooled.
  • the overall system offers the ability to efficiently and economically remove and cool combustor ash or other particulate material.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Gasification And Melting Of Waste (AREA)

Abstract

L'invention concerne un système de transport et de refroidissement de cendres de chaudière qui comporte (ou est destiné à fonctionner conjointement avec) une chaudière (10) à lit fluidisé de centrale. La chaudière (10) requiert un lit de cendres dans lequel un volume prédéterminé de cendres est maintenu. Lorsqu'elles se sont accumulées dans le lit jusqu'à la limite supérieure du volume prescrit, les cendres sont évacuées de la chaudière par une sortie (14) prévue à cet effet. Un appareil de régularisation et de transport (36) de matières particulaires est accouplé à la sortie (14) de cendre de la chaudière, de sorte qu'il amène ou pompe la cendre à l'extérieur de la chaudière (10) à une vitesse correspondant aux besoins d'enlèvement des cendres de la chaudière (14). L'appareil de régularisation (36) comporte une paire de parois mobiles (telles que les parois d'une paire de disques rotatifs), entre lesquelles les cendres ou d'autres particules passent et sont ainsi déplacées à une vitesse dépendant de la vitesse de déplacement des parois. Ledit appareil (36) présente une sortie reliée à l'extrémité d'entrée d'un refroidisseur à tambour rotatif.
PCT/US1996/001317 1995-02-01 1996-01-31 Systeme de manipulation et de transport de matieres particulaires du type cendres chaudes Ceased WO1996024810A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU52954/96A AU5295496A (en) 1995-02-01 1996-01-31 Method and system for handling and transporting hot ash and particulate material and controlling the bed of a fluidized bed apparatus

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US38225895A 1995-02-01 1995-02-01
US08/382,258 1995-02-01

Publications (1)

Publication Number Publication Date
WO1996024810A1 true WO1996024810A1 (fr) 1996-08-15

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Country Status (2)

Country Link
AU (1) AU5295496A (fr)
WO (1) WO1996024810A1 (fr)

Cited By (12)

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Publication number Priority date Publication date Assignee Title
US6832887B2 (en) 2002-04-09 2004-12-21 K-Tron Technologies, Inc. Bulk material pump feeder
US7044288B2 (en) 2002-04-09 2006-05-16 K-Tron Technologies, Inc. Bulk material pump feeder with reduced disk jamming
US7677864B2 (en) 2005-10-12 2010-03-16 K-Tron Technologies, Inc. Bulk material pump feeder with reduced disk jamming, compliant disks
EP2359927A1 (fr) * 2010-02-11 2011-08-24 Alstom Technology Ltd Système rotatif de régénération de cendres résiduelles
CN102718216A (zh) * 2012-06-14 2012-10-10 北京思能达电力电子技术有限公司 旋转筒式余热回收及块状物一次成型传输装置
US8496412B2 (en) 2006-12-15 2013-07-30 General Electric Company System and method for eliminating process gas leak in a solids delivery system
US9156631B2 (en) 2012-12-04 2015-10-13 General Electric Company Multi-stage solids feeder system and method
US9702372B2 (en) 2013-12-11 2017-07-11 General Electric Company System and method for continuous solids slurry depressurization
US9784121B2 (en) 2013-12-11 2017-10-10 General Electric Company System and method for continuous solids slurry depressurization
US10018416B2 (en) 2012-12-04 2018-07-10 General Electric Company System and method for removal of liquid from a solids flow
CN108342584A (zh) * 2018-04-19 2018-07-31 重庆新格有色金属有限公司 铝灰处理系统
CN111853763A (zh) * 2020-06-08 2020-10-30 山鹰华南纸业有限公司 一种循环流化床锅炉返料循环灰补给方法

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US5042402A (en) * 1990-08-15 1991-08-27 Tampella Keeler Incorporated Multi-sided watercooled rotary combustor
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US4443186A (en) * 1982-04-14 1984-04-17 The United States Of America As Represented By The United States Department Of Energy Solar heated rotary kiln
US5042402A (en) * 1990-08-15 1991-08-27 Tampella Keeler Incorporated Multi-sided watercooled rotary combustor
US5297957A (en) * 1992-06-11 1994-03-29 Thermotech Systems Corp. Organic waste incinerator

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8083051B2 (en) 2002-04-09 2011-12-27 K-Tron Technologies, Inc. Bulk material pump feeder with reduced disk jamming
US7044288B2 (en) 2002-04-09 2006-05-16 K-Tron Technologies, Inc. Bulk material pump feeder with reduced disk jamming
US7303062B2 (en) 2002-04-09 2007-12-04 Baer Timothy R Bulk material pump feeder with reduced disk jamming
US6832887B2 (en) 2002-04-09 2004-12-21 K-Tron Technologies, Inc. Bulk material pump feeder
US7677864B2 (en) 2005-10-12 2010-03-16 K-Tron Technologies, Inc. Bulk material pump feeder with reduced disk jamming, compliant disks
US8496412B2 (en) 2006-12-15 2013-07-30 General Electric Company System and method for eliminating process gas leak in a solids delivery system
EP2359927A1 (fr) * 2010-02-11 2011-08-24 Alstom Technology Ltd Système rotatif de régénération de cendres résiduelles
CN102188908A (zh) * 2010-02-11 2011-09-21 阿尔斯托姆科技有限公司 旋转炉底部灰分再生体系
US9074767B2 (en) 2010-02-11 2015-07-07 Alstom Technology Ltd Rotary bottom ash regeneration system
US10005055B2 (en) 2010-02-11 2018-06-26 General Electric Technology Gmbh Rotary bottom ash regeneration system
CN102718216A (zh) * 2012-06-14 2012-10-10 北京思能达电力电子技术有限公司 旋转筒式余热回收及块状物一次成型传输装置
US9156631B2 (en) 2012-12-04 2015-10-13 General Electric Company Multi-stage solids feeder system and method
US10018416B2 (en) 2012-12-04 2018-07-10 General Electric Company System and method for removal of liquid from a solids flow
US9702372B2 (en) 2013-12-11 2017-07-11 General Electric Company System and method for continuous solids slurry depressurization
US9784121B2 (en) 2013-12-11 2017-10-10 General Electric Company System and method for continuous solids slurry depressurization
CN108342584A (zh) * 2018-04-19 2018-07-31 重庆新格有色金属有限公司 铝灰处理系统
CN111853763A (zh) * 2020-06-08 2020-10-30 山鹰华南纸业有限公司 一种循环流化床锅炉返料循环灰补给方法

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