EP0090641B1 - Fluidized bed heat exchanger - Google Patents
Fluidized bed heat exchanger Download PDFInfo
- Publication number
- EP0090641B1 EP0090641B1 EP19830301758 EP83301758A EP0090641B1 EP 0090641 B1 EP0090641 B1 EP 0090641B1 EP 19830301758 EP19830301758 EP 19830301758 EP 83301758 A EP83301758 A EP 83301758A EP 0090641 B1 EP0090641 B1 EP 0090641B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- bed
- drain
- heat exchanger
- air
- plate
- 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.)
- Expired
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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
- F23C10/24—Devices for removal of material from the bed
Definitions
- This invention relates to a fluidized bed heat exchanger and, more particularly, to a heat exchanger in which heat is generated by the combustion of particulate fuel in a fluidized bed and a method of operation thereof.
- fluidized beds have long been recognized as an attractive way of generating heat.
- air is passed through a perforated plate or grid supporting particulate material which usually includes a mixture of a fuel material, such as high sulphur bituminous coal, and an adsorbent material for adsorbing the sulphur released as a result of the combustion of the coal.
- a fuel material such as high sulphur bituminous coal
- an adsorbent material for adsorbing the sulphur released as a result of the combustion of the coal.
- the bed behaves like a coiling liquid which promotes the combustion of the fuel.
- the basic advantage of such an arrangement include a relatively high heat transfer rate, substantially uniform bed temperature, combustion at relatively low temperatures, ease of handling the coal, a reduction in corrosion and boiler fouling and a reduction in heat exchanger (e.g. boiler) size.
- the coal and adsorbent are continuously introduced into the bed by suitable feeders, injectors, or the like, and coal ash and adsorbent are discharged from the lower portion of the bed to a screw cooler, conveyor belt or the like, usually through gravity drain pipes having entrances registering with discharge openings formed in the heat exchanger housing at the sides of the perforated support plate, as disclosed for example in DE-A-2 929 056 wherein a plurality of special pockets for receiving the upper ends of a corresponding plurality of drain pipes are provided in the housing side walls, and the lower end of the pipes communicating with said screw cooler, conveyor belt, or the like.
- a fluidized bed heat exchanger comprises an enclosure, a perforated support plate within said enclosure supporting a bed of particulate material which includes a fuel material and an adsorbent material, means for introducing air through perforations in the plate to fluidize said bed, means for starting combustion in said bed by which relatively heavy fuel ash particles are formed, means for introducing additional particulate material to said bed, and a drain for discharging spent particulate material from said bed, characterised in that said drain comprises a substantially vertical tubular means which extends through the perforated plate in a perforated region thereof so as to define a drain inlet for particulate material within said bed, said tubular means including separating means for providing a classifying flow of air through said drain and into said bed such as to produce within said bed at said inlet and coaxially with said drain a substantially vertical, generally conical, region of low density whereby said relatively heavy fuel ash particles migrate toward the said low density region and sink into the drain whilst the particles of said adsorbent material
- the air flow can of course be varied to control the return of the adsorbent particles which are drawn into the drain pipe by the fuel ash particles.
- a fluidized bed heat exchanger can be operated in such a way that substantially all of the fuel, normally coal, is fluidized and in which the ash, though prevented from clogging the drain pipe, is permitted to discharge through it while adsorbent material is selectively prevented from doing so.
- the exchanger can also be operated in such a manner that the level of the fluidized bed is precisely controlled.
- a fluidized bed heat exchanger embodying the present invention has a perforate plate supporting a fluidized bed of particulate material and a drain pipe to which a source of compressed air is connected to flow upwardly through the drain pipe and into the material of the fluidized bed above the drain pipe, thereby preventing the heavy pieces of coal ash from accumulating.
- the upward flow of air also results in a low density area in the fluidized bed in a generally conical region above the inlet to the drain pipe, thereby providing less support for the particulate material in the region above the drain pipe.
- the heavier particles of the fluidized bed tend to migrate toward the low density region and to sink into the drain pipe.
- the flow of compressed air is selected so that it forms a separating air screen by which the relatively light particles of adsorbent material are buoyed and lifted upwardly, while the heavier coal ash particles are pulled by gravity down through the upwardly flowing compressed air into the drain pipe.
- the area in the fluidized bed around the inlet to the drain pipe is kept substantially free of any accumulation of material, and the light adsorbent material particles are retained in the fluidized bed, while the heavier coal ash particles are allowed to continuously and freely discharge through the drain pipe. Since the coal ash particles in a heat exchanger of the invention can drain relatively freely, they discharge at a relatively constant rate. The rate of particulate material flowing into the fluidized bed can then be adjusted whereby the level of the fluidized bed can be precisely controlled.
- Reference numeral 6 refers in general to an enclosure forming a major portion of the fluidized bed heat exchanger which may be in the form of a boiler, a combustor, a process reactor or any similar device.
- the enclosure 6 comprises a front wall 8, a rear wall 10, and two sidewalls, one of which is shown by the reference numeral 12.
- Each wall is formed by a plurality of vertically extending tubes 14 disposed in spaced, parallel relationship and connected together by a plurality of elongated fins 16 extending for the entire lengths of the tubes 14 and connected to diametrically opposed surfaces of the tubes in a conventional manner.
- the upper portion of the enclosure 6 is not shown for the convenience of presentation, it being understood that it comprises a convection section, a roof and an outlet for allowing the combustion gases to discharge, also in a conventional manner.
- a bed of particulate material shown in general by the reference numeral 18, is disposed within the heat exchanger 6 and rests on a plate 20 extending horizontally in the lower portion of the heat exchanger and having a plurality of perforations 21.
- the bed 18 can comprise a mixture of discrete particles of fuel material, such as bituminous coal, and an adsorbent, such as limestone, for adsorbing the sulphur released by the combustion of the fuel material.
- An air plenum 22 is provided immediately below the perforated plate 20 and an air inlet pipe 24 is provided through the plenum for distributing air from an external source (not shown) to the plenum under the control of a valve 26. Since the valve 26 can be of a conventional design, it will not be described in any further detail.
- a bed light-off burner 28 is mounted through the front wall 18 immediately above the plate 20 for initially lighting off the bed 18 during startup.
- the feeders 30, 32 and 34 receive particulate coal from inlet ducts or the like, and are controlled by valves or other flow control devices to feed the coal particles onto the upper surface of the bed 18.
- the feeders 30, 32 and 34 can operate by gravity discharge or can be in the form of spreader feeders or any other similar device. It is understood that feeders identical to the feeders 30, 32 and 34 and controlled by identical devices can also be provided through one or more of the front wall 8, the rear wall 10 and the other side wall 12, and that similar feeders and control devices can also be provided for discharging the adsorbent onto the bed 18.
- a pair of horizontal headers 40 are connected in fluid communication with the tubes 14 forming the front wall 8 and the rear wall 10, and another pair of horizontal headers 42 are connected in fluid communication with the tubes 14 forming the side walls 12. It is understood that headers similar to the headers 40 and 42 are provided in communication with the upper ends of the walls 8, 10 and 12. As a result, a fluid to be heated can be sequentially or simultaneously passed through the walls 8, 10 and 12 to pick up the heat from the fluidized bed in a.conventional manner.
- a drain 43 extends through the air plenum 22 and includes an outer pipe 44, an inner pipe 46 defining a throat concentrically disposed within the outer pipe 44, and a bevelled collar 48 secured between the outer and inner discharge pipes 44 and 46 at their upper ends so that an upper edge of the bevelled collar 48 is level with the lower surface of the perforated plate 20 to form a gradually narrowing inlet for the particulate coal ash entering the drain 43.
- the inlet is positioned at an opening 49 defined in the perforated plate 20.
- the bevelled collar 48 may be secured in any suitable manner, as by threadedly connecting the bevelled collar to the external surface of the inner pipe 46 and welding the bevelled collar to the outer pipe 44.
- the outer pipe 44 is supported by a threaded connection or other suitable connection to an annular flange 50 depending from the lower surface of the perforated plate 20.
- the outer and inner pipes 44 and 46 extend downwardly through a bottom wall 52 of the plenum 22 where they are guided by a collar 54 interposed between the outer pipe 44 and an annular flange 56 depending from the lower wall 52 of the plenum 22.
- the outer and inner pipes 44 and 46 terminate at lower ends which are welded or otherwise suitably secured to a flat annular plate 58 which extends radially outward from the lower end of the inner pipe 46.
- the flat annular plate 58 includes a plurality of apertures 62 spaced outward from the outer -pipe 44 for receiving fasteners, such as nuts and bolts 63, to connect the flange 58 t& a compressed air inlet assembly 64.
- the compressed air inlet assembly 64 includes a compressed air inlet pipe 66 having a lateral inlet port 68 which is connected to a source of compressed air (not shown), the flow of compressed air to the inlet pipe 66 being controlled by a valve 70.
- the compressed air inlet pipe 66 includes a radially extending upper flange 72 including a plurality of apertures 74 by which the nuts and bolts 63 can connect the flange 72 to the flange 58.
- An inner pipe 76 including at its upper end an outwardly flaring frustoconical plate 78 having a plurality of perforations 80, is positioned concentrically within the compressed air inlet pipe 66.
- the frustoconical plate 78 includes a central aperture 81 through which the draining coal ash particles can pass.
- the upper end of the frustoconical plate 78 includes an outwardly extending flange 82 which overlies the flange 72 and includes apertures 84 in alignment with the apertures 74, so that the flange 82 can be clamped between the flanges 72 and 58 when the appropriate fasteners are installed.
- a lower annular flange 86 extends radially outward from the lower end of the inner pipe 76 beyond the air inlet pipe 66 so as to define, with the air inlet pipe 66, the inner pipe 76 and the frustoconical plate 78, an annular plenum chamber 88.
- a suitable device such as a rotary feeder 90, is secured at the lower end of the inner pipe 76 to control the discharge of the coal ash.
- a rotary feeder has been indicated in the drawings, other suitable discharge devices, such as screw feeders, can be employed.
- valve 26 associated with the air inlet pipe 24 is opened to allow air to pass up through the plenum 22 and through the perforations 21 in the perforated plate 20.
- the light-off burner 28 is then fired to heat the material in the bed until the temperature of the material reaches a predetermined level, whereby combustion is started and relatively heavy coal ash particles begin to form, at which time particulate fuel is discharged from the feeders 30, 32 and 34, and adsorbent material is discharged from other feeders (not shown) onto the upper surface of the bed 18 as needed.
- the light-off burner 28 is turned off while the feeders 30, 32 and 34 continue to distribute particulate fuel to the upper surface of the bed in accordance with predetermined feed rates.
- Fluid, such as water, to be heated is passed into the headers 40 and 42 where it passes simultaneously, or in sequence, through the tubes 14 forming the walls 8, 10 and 12 to add heat from the fluidized bed to the fluid before it is passed to external apparatus for further processing.
- Compressed air is admitted to the annular plenum chamber 88 through the compressed air inlet port 68 by the manipulation of the valve 70.
- the compressed air flows through the perforations 80 in the frustoconical plate 78 and increases in velocity when it enters the throat defined by the inner drain pipe 46, from which it flows directly upward through the fluidized bed 18, creating a generally conical low density region in the fluidized bed above the drain 43.
- the bed material over the drain 43 is prevented from accumulating around the inlet to the drain.
- the material of the fluidized bed 18 tends to migrate toward the low density region over the drain 43.
- the diameter of the inner drain pipe 46 and the flow of air from the compressed air source are selected so that the air flowing up through the drain 43 defines an air screen separating the relatively lightweight adsorbent material particles from the heavier coal ash particles.
- the adsorbent particles are normally eliminated in the flue gas, the coal ash particles are continuously discharged through the drain 43 and additional adsorbent and coal is continuously supplied to the top of the fluidized bed 18 to maintain a continuous circulation of material and a constant level in the fluidized bed 18.
- the flow of coal ash particles into the drain 43 occurs freely, rather than being unpredictably restricted or blocked by accumulations around the entrance to the drain 43, it occurs at a relatively constant rate, so that the rate of particulate material being fed to the fluidized bed 18 can be adjusted, whereby the level of the fluidized bed 18 can be precisely controlled. If it is desired to increase the rate of removal of the adsorbent material from the fluidized bed 18, the flow of compressed air through the drain pipe 43 can be reduced so that the lighter adsorbent material particles will fall through the drain pipe 43 along with the heavier coal ash particles. By adjusting the amount of compressed air flowing through the drain 43 into the fluidized bed 18 the size of particles which will be allowed to fall through the drain 43 can be controlled.
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Fluidized-Bed Combustion And Resonant Combustion (AREA)
- Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
Description
- This invention relates to a fluidized bed heat exchanger and, more particularly, to a heat exchanger in which heat is generated by the combustion of particulate fuel in a fluidized bed and a method of operation thereof.
- The use of fluidized beds has long been recognized as an attractive way of generating heat. In a normal fluidized bed arrangement, air is passed through a perforated plate or grid supporting particulate material which usually includes a mixture of a fuel material, such as high sulphur bituminous coal, and an adsorbent material for adsorbing the sulphur released as a result of the combustion of the coal. As a result of the air passing through the bed, the bed behaves like a coiling liquid which promotes the combustion of the fuel. The basic advantage of such an arrangement include a relatively high heat transfer rate, substantially uniform bed temperature, combustion at relatively low temperatures, ease of handling the coal, a reduction in corrosion and boiler fouling and a reduction in heat exchanger (e.g. boiler) size.
- In the fluidized bed combustion process, the coal and adsorbent are continuously introduced into the bed by suitable feeders, injectors, or the like, and coal ash and adsorbent are discharged from the lower portion of the bed to a screw cooler, conveyor belt or the like, usually through gravity drain pipes having entrances registering with discharge openings formed in the heat exchanger housing at the sides of the perforated support plate, as disclosed for example in DE-A-2 929 056 wherein a plurality of special pockets for receiving the upper ends of a corresponding plurality of drain pipes are provided in the housing side walls, and the lower end of the pipes communicating with said screw cooler, conveyor belt, or the like. However, in arrangements in which the size of the coal extends over a relatively large range, relatively heavy pieces of coal ash tend to migrate to an area above the drain pipe and form a dense area that is difficult, if not impossible, to fluidize. As a result, the heavy pieces of coal ash do not drain, but rather cause a clogging of the drain pipe and an attendant severe curtailment in the operating efficiency of the bed.
- Furthermore, in the operation of the fluidized bed, in order to maximize heat transfer efficiency, it is desirable to maintain close control over the level of material in the bed. Precise control is difficult to achieve in a fluidized bed in which new material is continuously being introduced, if the drain tends to become clogged. An effective solution to the problem of such drain clogging is described in US-A-4,335,661, and GB-A-2 114 990 (published on 01.09.83).
- In addition to maintaining a continuously controllable discharge through the drain, it is also desirable to retain the relatively light adsorbent material particles in the fluidized bed, while permitting only the relatively heavy coal ash particles to discharge through the drain. In this manner, the adsorbent material is retained in the fluidized bed for a longer time to adsorb more sulphur from the combustion of the coal and, as a result, less new adsorbent material need be continuously introduced. There is an acceptable loss or attrition of adsorbent material in the normal operation of the bed by the reduction of the adsorbent material to fine particle size due to the boiling action of the bed and the grinding of the particles against one another, and by the entrainment of the fine adsorbent material particles in the fluidizing gas, by which they are carried out through the flue.
- According to the present invention a fluidized bed heat exchanger comprises an enclosure, a perforated support plate within said enclosure supporting a bed of particulate material which includes a fuel material and an adsorbent material, means for introducing air through perforations in the plate to fluidize said bed, means for starting combustion in said bed by which relatively heavy fuel ash particles are formed, means for introducing additional particulate material to said bed, and a drain for discharging spent particulate material from said bed, characterised in that said drain comprises a substantially vertical tubular means which extends through the perforated plate in a perforated region thereof so as to define a drain inlet for particulate material within said bed, said tubular means including separating means for providing a classifying flow of air through said drain and into said bed such as to produce within said bed at said inlet and coaxially with said drain a substantially vertical, generally conical, region of low density whereby said relatively heavy fuel ash particles migrate toward the said low density region and sink into the drain whilst the particles of said adsorbent material are retained within the bed. The air flow can of course be varied to control the return of the adsorbent particles which are drawn into the drain pipe by the fuel ash particles. By this means, a fluidized bed heat exchanger can be operated in such a way that substantially all of the fuel, normally coal, is fluidized and in which the ash, though prevented from clogging the drain pipe, is permitted to discharge through it while adsorbent material is selectively prevented from doing so. The exchanger can also be operated in such a manner that the level of the fluidized bed is precisely controlled.
- A fluidized bed heat exchanger embodying the present invention has a perforate plate supporting a fluidized bed of particulate material and a drain pipe to which a source of compressed air is connected to flow upwardly through the drain pipe and into the material of the fluidized bed above the drain pipe, thereby preventing the heavy pieces of coal ash from accumulating. The upward flow of air also results in a low density area in the fluidized bed in a generally conical region above the inlet to the drain pipe, thereby providing less support for the particulate material in the region above the drain pipe. Thus, the heavier particles of the fluidized bed tend to migrate toward the low density region and to sink into the drain pipe. The flow of compressed air is selected so that it forms a separating air screen by which the relatively light particles of adsorbent material are buoyed and lifted upwardly, while the heavier coal ash particles are pulled by gravity down through the upwardly flowing compressed air into the drain pipe. Thus, the area in the fluidized bed around the inlet to the drain pipe is kept substantially free of any accumulation of material, and the light adsorbent material particles are retained in the fluidized bed, while the heavier coal ash particles are allowed to continuously and freely discharge through the drain pipe. Since the coal ash particles in a heat exchanger of the invention can drain relatively freely, they discharge at a relatively constant rate. The rate of particulate material flowing into the fluidized bed can then be adjusted whereby the level of the fluidized bed can be precisely controlled.
- The invention will now be described by way of example and with reference to the accompanying drawings wherein:-
- Figure 1 is a vertical sectional view of the fluidized bed heat exchanger of the present invention, and
- Figure 2 is an enlarged cross-sectional view of the drain pipe of Figure 1.
- Reference numeral 6 refers in general to an enclosure forming a major portion of the fluidized bed heat exchanger which may be in the form of a boiler, a combustor, a process reactor or any similar device. The enclosure 6 comprises a
front wall 8, a rear wall 10, and two sidewalls, one of which is shown by thereference numeral 12. Each wall is formed by a plurality of vertically extendingtubes 14 disposed in spaced, parallel relationship and connected together by a plurality ofelongated fins 16 extending for the entire lengths of thetubes 14 and connected to diametrically opposed surfaces of the tubes in a conventional manner. The upper portion of the enclosure 6 is not shown for the convenience of presentation, it being understood that it comprises a convection section, a roof and an outlet for allowing the combustion gases to discharge, also in a conventional manner. - A bed of particulate material, shown in general by the
reference numeral 18, is disposed within the heat exchanger 6 and rests on aplate 20 extending horizontally in the lower portion of the heat exchanger and having a plurality of perforations 21. Thebed 18 can comprise a mixture of discrete particles of fuel material, such as bituminous coal, and an adsorbent, such as limestone, for adsorbing the sulphur released by the combustion of the fuel material. - An
air plenum 22 is provided immediately below theperforated plate 20 and anair inlet pipe 24 is provided through the plenum for distributing air from an external source (not shown) to the plenum under the control of avalve 26. Since thevalve 26 can be of a conventional design, it will not be described in any further detail. A bed light-offburner 28 is mounted through thefront wall 18 immediately above theplate 20 for initially lighting off thebed 18 during startup. - Three overbed
feeders sidewall 12. Thefeeders bed 18. Thefeeders feeders front wall 8, the rear wall 10 and theother side wall 12, and that similar feeders and control devices can also be provided for discharging the adsorbent onto thebed 18. - A pair of
horizontal headers 40 are connected in fluid communication with thetubes 14 forming thefront wall 8 and the rear wall 10, and another pair ofhorizontal headers 42 are connected in fluid communication with thetubes 14 forming theside walls 12. It is understood that headers similar to theheaders walls walls - As can be seen in greater detail in Figure 2, a
drain 43 extends through theair plenum 22 and includes anouter pipe 44, aninner pipe 46 defining a throat concentrically disposed within theouter pipe 44, and abevelled collar 48 secured between the outer andinner discharge pipes collar 48 is level with the lower surface of theperforated plate 20 to form a gradually narrowing inlet for the particulate coal ash entering thedrain 43. The inlet is positioned at an opening 49 defined in theperforated plate 20. The bevelledcollar 48 may be secured in any suitable manner, as by threadedly connecting the bevelled collar to the external surface of theinner pipe 46 and welding the bevelled collar to theouter pipe 44. Theouter pipe 44 is supported by a threaded connection or other suitable connection to anannular flange 50 depending from the lower surface of the perforatedplate 20. The outer andinner pipes bottom wall 52 of theplenum 22 where they are guided by acollar 54 interposed between theouter pipe 44 and anannular flange 56 depending from thelower wall 52 of theplenum 22. The outer andinner pipes annular plate 58 which extends radially outward from the lower end of theinner pipe 46. The flatannular plate 58 includes a plurality ofapertures 62 spaced outward from the outer -pipe 44 for receiving fasteners, such as nuts andbolts 63, to connect theflange 58 t& a compressedair inlet assembly 64. - The compressed
air inlet assembly 64 includes a compressedair inlet pipe 66 having alateral inlet port 68 which is connected to a source of compressed air (not shown), the flow of compressed air to theinlet pipe 66 being controlled by avalve 70. The compressedair inlet pipe 66 includes a radially extendingupper flange 72 including a plurality ofapertures 74 by which the nuts andbolts 63 can connect theflange 72 to theflange 58. Aninner pipe 76, including at its upper end an outwardly flaringfrustoconical plate 78 having a plurality ofperforations 80, is positioned concentrically within the compressedair inlet pipe 66. Thefrustoconical plate 78 includes acentral aperture 81 through which the draining coal ash particles can pass. The upper end of thefrustoconical plate 78 includes an outwardly extendingflange 82 which overlies theflange 72 and includesapertures 84 in alignment with theapertures 74, so that theflange 82 can be clamped between theflanges annular flange 86 extends radially outward from the lower end of theinner pipe 76 beyond theair inlet pipe 66 so as to define, with theair inlet pipe 66, theinner pipe 76 and thefrustoconical plate 78, anannular plenum chamber 88. - A suitable device, such as a
rotary feeder 90, is secured at the lower end of theinner pipe 76 to control the discharge of the coal ash. Although a rotary feeder has been indicated in the drawings, other suitable discharge devices, such as screw feeders, can be employed. - In operation, the
valve 26 associated with theair inlet pipe 24 is opened to allow air to pass up through theplenum 22 and through the perforations 21 in theperforated plate 20. The light-offburner 28 is then fired to heat the material in the bed until the temperature of the material reaches a predetermined level, whereby combustion is started and relatively heavy coal ash particles begin to form, at which time particulate fuel is discharged from thefeeders bed 18 as needed. - After the
bed 18 has been fluidized and has reached a predetermined elevated temperature in accordance with the foregoing, the light-offburner 28 is turned off while thefeeders headers tubes 14 forming thewalls - Compressed air is admitted to the
annular plenum chamber 88 through the compressedair inlet port 68 by the manipulation of thevalve 70. The compressed air flows through theperforations 80 in thefrustoconical plate 78 and increases in velocity when it enters the throat defined by theinner drain pipe 46, from which it flows directly upward through the fluidizedbed 18, creating a generally conical low density region in the fluidized bed above thedrain 43. There is a greater volume of compressed air flowing upwardly over thedrain 43 than in any other region of thefluidized bed 18. As a result, the bed material over thedrain 43 is prevented from accumulating around the inlet to the drain. In addition, the material of thefluidized bed 18 tends to migrate toward the low density region over thedrain 43. Furthermore, the diameter of theinner drain pipe 46 and the flow of air from the compressed air source are selected so that the air flowing up through thedrain 43 defines an air screen separating the relatively lightweight adsorbent material particles from the heavier coal ash particles. Thus, when the particulate material of thefluidized bed 18 moves into the low density region over thedrain 43, the flow of compressed air from the drain forces the relatively lightweight adsorbent material particles upward, but permits the heavier coal ash particles to sink into thedrain 43, from which they are discharged by therotary feeder 90 or other suitable discharge device. - There is an inherent rate of attrition of the adsorbent particles due to their reduction to fine size by the collisions and abrasions of the boiling action of the
fluidized bed 18 and the resultant entrainment of the fine adsorbent particles by the fluidizing air, in which they are carried out through the flue. Thus, the adsorbent particles are normally eliminated in the flue gas, the coal ash particles are continuously discharged through thedrain 43 and additional adsorbent and coal is continuously supplied to the top of thefluidized bed 18 to maintain a continuous circulation of material and a constant level in thefluidized bed 18. Since the flow of coal ash particles into thedrain 43 occurs freely, rather than being unpredictably restricted or blocked by accumulations around the entrance to thedrain 43, it occurs at a relatively constant rate, so that the rate of particulate material being fed to thefluidized bed 18 can be adjusted, whereby the level of thefluidized bed 18 can be precisely controlled. If it is desired to increase the rate of removal of the adsorbent material from thefluidized bed 18, the flow of compressed air through thedrain pipe 43 can be reduced so that the lighter adsorbent material particles will fall through thedrain pipe 43 along with the heavier coal ash particles. By adjusting the amount of compressed air flowing through thedrain 43 into thefluidized bed 18 the size of particles which will be allowed to fall through thedrain 43 can be controlled.
Claims (7)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US36416382A | 1982-03-31 | 1982-03-31 | |
US364163 | 1982-03-31 |
Publications (3)
Publication Number | Publication Date |
---|---|
EP0090641A2 EP0090641A2 (en) | 1983-10-05 |
EP0090641A3 EP0090641A3 (en) | 1984-08-01 |
EP0090641B1 true EP0090641B1 (en) | 1988-01-07 |
Family
ID=23433320
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP19830301758 Expired EP0090641B1 (en) | 1982-03-31 | 1983-03-29 | Fluidized bed heat exchanger |
Country Status (5)
Country | Link |
---|---|
EP (1) | EP0090641B1 (en) |
JP (1) | JPH0236877B2 (en) |
CA (1) | CA1192792A (en) |
DE (1) | DE3375197D1 (en) |
IN (1) | IN159258B (en) |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
AT382227B (en) * | 1985-04-30 | 1987-01-26 | Simmering Graz Pauker Ag | METHOD AND DEVICE FOR THE COMBUSTION OF SOLID, LIQUID, GASEOUS OR PASTOUS FUELS IN A FLUIDIZED STOVE |
FI85758C (en) * | 1990-01-29 | 1992-05-25 | Tampella Oy Ab | FOERBRAENNINGSANLAEGGNING. |
US7025927B2 (en) | 2000-08-09 | 2006-04-11 | Asahi Tec Corporation | Hot air blowing type fluidized-bed furnace, rotary heat-treatment furnace, heat-treatment apparatus, and method of heat treatment |
FR3022611B1 (en) | 2014-06-19 | 2016-07-08 | Ifp Energies Now | METHOD AND INSTALLATION OF COMBUSTION BY OXYDO-REDUCTION IN CHEMICAL LOOP WITH CHECKING HEAT EXCHANGES |
Family Cites Families (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3370938A (en) * | 1965-07-30 | 1968-02-27 | Allied Chem | Method and apparatus for controlling particle size of fluidized beds |
US3776150A (en) * | 1972-03-06 | 1973-12-04 | Awt Systems Inc | Fluidized bed system for solid wastes |
US3935825A (en) * | 1975-02-24 | 1976-02-03 | Institute Of Gas Technology | Coal ash agglomeration device |
US4196676A (en) * | 1978-07-21 | 1980-04-08 | Combustion Power Company, Inc. | Fluid bed combustion method and apparatus |
US4330502A (en) * | 1980-06-16 | 1982-05-18 | A. Ahlstrom Osakeyhtio | Fluidized bed reactor |
US4335661A (en) * | 1980-09-24 | 1982-06-22 | Foster Wheeler Energy Corporation | Fluidized bed heat exchanger having an air assisted bed drain |
-
1983
- 1983-03-29 EP EP19830301758 patent/EP0090641B1/en not_active Expired
- 1983-03-29 DE DE8383301758T patent/DE3375197D1/en not_active Expired
- 1983-03-30 CA CA000424965A patent/CA1192792A/en not_active Expired
- 1983-03-30 IN IN202/DEL/83A patent/IN159258B/en unknown
- 1983-03-31 JP JP5406083A patent/JPH0236877B2/en not_active Expired - Lifetime
Also Published As
Publication number | Publication date |
---|---|
CA1192792A (en) | 1985-09-03 |
EP0090641A2 (en) | 1983-10-05 |
JPS58213187A (en) | 1983-12-12 |
DE3375197D1 (en) | 1988-02-11 |
JPH0236877B2 (en) | 1990-08-21 |
EP0090641A3 (en) | 1984-08-01 |
IN159258B (en) | 1987-04-18 |
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