CA1095697A - Aspirating feed funnel for fluidized reactor - Google Patents
Aspirating feed funnel for fluidized reactorInfo
- Publication number
- CA1095697A CA1095697A CA303,370A CA303370A CA1095697A CA 1095697 A CA1095697 A CA 1095697A CA 303370 A CA303370 A CA 303370A CA 1095697 A CA1095697 A CA 1095697A
- Authority
- CA
- Canada
- Prior art keywords
- feed
- mixing tube
- air
- funnel
- feed funnel
- 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
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E30/00—Energy generation of nuclear origin
- Y02E30/30—Nuclear fission reactors
Landscapes
- Devices And Processes Conducted In The Presence Of Fluids And Solid Particles (AREA)
- Crucibles And Fluidized-Bed Furnaces (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A feed device for introducing a dry feed into the reaction chamber of a fluidized bed reactor is provided with plurality of air nozzle which direct high speed jets of air along the feed path in the direction of feed to provide a continuous pressure barrier against excess back pressure in the reactor chamber.
A feed device for introducing a dry feed into the reaction chamber of a fluidized bed reactor is provided with plurality of air nozzle which direct high speed jets of air along the feed path in the direction of feed to provide a continuous pressure barrier against excess back pressure in the reactor chamber.
Description
US-195~ 697 This invention is directed to a novel gas sealing arrangement for the feed means of a fluidized bed reactor.
Fluidized bed reactors are extremely versatile apparatus, which, in various forms, can carry out the processes of drying, sizing, roasting, calcining and heat treatment of solids with gases in the chemical, metallurgical and other materials-processing fields. In the operation of certain fluidized bed applications, for example, metallurgical roasting, the feed material which is to be processed is sometimes so dry that it cannot be pumped, but must instead be handled by bulk handling equipment such as belts, screws and similar apparatus.
Under some operating conditions, the static pressure within the freeboard of the fluidized bed reactor exceeds the external or atmospheric pressure. When this occurs, it is difficult to get the dry feed material into the reactor without permitting the escape of noxious reaction gases, unless some positive means of sealing is provided for the feeding apparatus through which the feed material is passed into the fluidized bed reactor. The flow of gas out of the reactor through the feed apparatus may be of a volume and velocity sufficient to blow substantial quantities of solid feed back out of the feed apparatus and so disrupt the roasting process.
Various mechanical devices have been resorted to in the past to make an effective seal, such as double flap valves or arrangements whereby table, screw, or belt feeders operate under a sealing column of the feed material. This special equipment is costly to purchase and maintain and is subject to interruption leading to loss of production.
- Accordingly, there is a real need for an effective sealing means for use in connection with the feeding of dry US-1958 ~56~7 materials (which may be moist, but not pumpable) to fluidized bed reactors.
A novel sealing arrangement for the feed mechanism of a fluidized bed reactor has now been provided wherein the seal is effected by appropriately directed streams of air.
It is an object of the invention to provide an improved sealing means for the feed apparatus of a fluidized bed reactor.
It is a further object of this invention to provide a sealing means for the feed apparatus of a fluidized bed reactor which provides a pressure barrier against excess pressure within the reaction chamber of the fluidized bed reactor while allowing introduction of dry feed into the reaction chamber.
Other objects and advantages will become apparent from the following description taken in conjunction with the accompanying drawings in which:
Figure 1 is a view in elevation and partially in section of a fluidized bed reactor having a roof-mounted feeding apparatus, Figure 2 is a sectional view of a dry feed device for a fluidized bed reactor provided with the sealin~ means of the present invention, Figure 3 is a view of a nozzle suitable for use in the sealing means of a present invention, Figure 4 is a side view, partially in section, of a dry feed device for a fluidized bed reactor in which feed is introduced through the size wall of the reactor, and Figure 5 is a top view, partially in section of the dry feed device depited in Figure 4.
Fluidized bed reactors are extremely versatile apparatus, which, in various forms, can carry out the processes of drying, sizing, roasting, calcining and heat treatment of solids with gases in the chemical, metallurgical and other materials-processing fields. In the operation of certain fluidized bed applications, for example, metallurgical roasting, the feed material which is to be processed is sometimes so dry that it cannot be pumped, but must instead be handled by bulk handling equipment such as belts, screws and similar apparatus.
Under some operating conditions, the static pressure within the freeboard of the fluidized bed reactor exceeds the external or atmospheric pressure. When this occurs, it is difficult to get the dry feed material into the reactor without permitting the escape of noxious reaction gases, unless some positive means of sealing is provided for the feeding apparatus through which the feed material is passed into the fluidized bed reactor. The flow of gas out of the reactor through the feed apparatus may be of a volume and velocity sufficient to blow substantial quantities of solid feed back out of the feed apparatus and so disrupt the roasting process.
Various mechanical devices have been resorted to in the past to make an effective seal, such as double flap valves or arrangements whereby table, screw, or belt feeders operate under a sealing column of the feed material. This special equipment is costly to purchase and maintain and is subject to interruption leading to loss of production.
- Accordingly, there is a real need for an effective sealing means for use in connection with the feeding of dry US-1958 ~56~7 materials (which may be moist, but not pumpable) to fluidized bed reactors.
A novel sealing arrangement for the feed mechanism of a fluidized bed reactor has now been provided wherein the seal is effected by appropriately directed streams of air.
It is an object of the invention to provide an improved sealing means for the feed apparatus of a fluidized bed reactor.
It is a further object of this invention to provide a sealing means for the feed apparatus of a fluidized bed reactor which provides a pressure barrier against excess pressure within the reaction chamber of the fluidized bed reactor while allowing introduction of dry feed into the reaction chamber.
Other objects and advantages will become apparent from the following description taken in conjunction with the accompanying drawings in which:
Figure 1 is a view in elevation and partially in section of a fluidized bed reactor having a roof-mounted feeding apparatus, Figure 2 is a sectional view of a dry feed device for a fluidized bed reactor provided with the sealin~ means of the present invention, Figure 3 is a view of a nozzle suitable for use in the sealing means of a present invention, Figure 4 is a side view, partially in section, of a dry feed device for a fluidized bed reactor in which feed is introduced through the size wall of the reactor, and Figure 5 is a top view, partially in section of the dry feed device depited in Figure 4.
- 2 -l~gS~9~
Generally speaking, the sealing means of the present invention is associated with a feed apparatus for a fluidized bed reactor and operates to direct a plurality of jets of gas in the direction of feed flow to resist the back pressure of the reaction chamber into which the feed flows.
More specifically, in the present invention a feed conduit serves to introduce dry feed into the reaction chamber of a fluidized bed reactor through a mixing tube, and a seal against reactor bac~ pressure is effected by a plurality of nozzles which direct air jets into the mixing tube, generally in the direction of feed flow. The pressurized air for the air jets is supplied by an annular plenum chamber which surrounds the feed path and is in communication with the nozzles.
Referring now to the drawings, in Figure 1 there is illustrated a fluidized bed reactor 10 having a metal shell 12.
I'he interior of the reactor 10 is divided into two compartments by a constriction plate 19, with a reaction chamber 14 above the constriction plate and a smaller windbox 16 below the constriction plate. A plurality of tuyeres or perforations pierce the constriction plate 19 and provide communication between the windbox 16 and the reaction chamber 14. In the reaction chamber 14 a body of finely divided particulate solids 18 rests on the constriction plate 19. Air inlet means 22 is provided for the windbox 16 and exhaust conduit 24 is in communication with the reaction chamber 14. A product outlet conduit 26 communicates with the fluidized bed 18 within the reaction chamber 14 for the withdrawal of product. The windbox 16 is provided with a cleanout port 27 for the removal of particulate solids which sift through the tuyeres of the ~5697 constriction plate 14 and accumulate in the lower part of the windbox. The feed means 30 is located on the roof 13 of the fluidized bed reactor and is supported by a cylindrical housing 28 which is fixed to the roof 13.
Turning now to Fig. 2 for a detailed description of feed means 30, it is seen that feed belt 36 is located above feed funnel 32 and turns about pulley 38 50 that it is positioned to deliver a dry feed to funnel 32. The mixing tube 52, which is a cylindrical conduit member extending into reaction chamber 14 having a flared mouth portion 52' is supported by the top surface 29 of the cylindrical housing 28. The feed funnel 32 has its narrow lower exit portion adjacent the mouth 52' of mixing tube 52. A flange 46 is joined to both the lower end of the feed funnel 32 and the flared mouth portion 52' of the mixing tube 52, providing a shoulder between the funnel and the mixing tube and overlying the top surface member 29 to which it is secured. The wall member 43 defines the top and outer periphery of an annular plenum chamber 42 which is positioned about the lower portion of the feed funnel 32. The bottom wall of the plenum chamber 42 is provided by the upper surface of the aforementioned flange 46. The enclosure of the plenum chamber 42 is completed by the inner wall 41 which surrounds the lower end of feed funnel 32. A conduit 44 communicated with the plenum chamber 42. In the flange 46 there are positioned a plurality of nozzle members 56 which communicate between the plenum chamber 42 and the flared mouth portion 52' of the mixing tube 52.
; The structure of the nozzles 56 is more clearly seen in Figure 3 where the flange 46 is shown with the nozzles 56 mounted therein. The nozzles 56 are threaded bolt-like members, 11~95697 each having an axial bore 58 therein. As best seen in Figure 2, the nozzles are positioned about the feed path at an inwardly inclined angle, preferably focused at a point downward from the feed funnel 32 and well within the mixing tube 52.
The fèed means 30 may also be provided with a device for dispersing and evenly distributing the feed issuing from mixing tube 52 over the surface of fluid bed 18. The dispersing device in this case comprises a plurality of gas lines 71 (only one of which is illustrated in Figure 2) which terminate in nozzles lo 78. As the feed enters the reaction chamber 14, the dispersing device is actuated and strong jets of gas (air is very usual) impinge on the feed particles and scatter them over the bed surface. This helps maintain uniform conditions in the bed.
While the pressure barrier as described in connection with the embodiment of Figure 2 is supplied by a plurality of jet nozzles 56, it is evident that a fine, generally annular, slot in the member 46 may be substituted for the nozzles to produce an annular jet stream focused within mixing tube 52.
In operation, the feed belt 36 supplies a dry feed to feed funnel 32 of feed means 30. Under the influence of gravity, the feed falls through feed funnel 32 and into mixing tube 52.
Particularly under start-up conditions, where a roasting process is invo}ved, the pressure within the reaction chamber 14 may substantially exceed ambient pressure, with the consequence that the feed may be blown back and out through the feed funnel.
Under these conditions, air is supplied to plenum chamber 42 through conduit 44, which may be in communication with the same blower system which provides fluidizing air for windbox 16 through conduit 22. Thus, air under pressure is present in US-1958 ~ 7 plenum chamber 42. The pressurized air is ~irected by the nozzles 56 into the mixing tube 52 and this airflow effectively seals the feed system against the back pressure within the reaction chamber.
In a typical application of the invention, a roof-mounted aspirating feed funnel is incorporated in a fluid bed reactor, operating on a dry pyrite feed, wherein the excess freeboard pressure in the reaction chamber is 5 inches water column (0.18 psig). This positive pressure is sufficient to blow noxious gases and substantial amounts of solid fine feed back through the dry feed system. The sealing is effected in this reactor, which has a feed funnel throat of 7-5/8" internal diameter, a mixing tube of 11" internal diameter and experiences a back pressure of 17.1 lbs. force (Q F), by establishing conditions which satisfy the equation where change in system momentum equals the force required to hold back the elevated furnace pressure:
~F = WaVa + WlVl ~ W2V2 A2 (P2 1) g g g ~ F = Back pressure force exerted by furnace atmosphere against outside air pressure, lbs.
Wa = Weight flow of aspirating air, lbs/sec.
Va = Jet velocity of aspirating air, ft/sec.
Wl = Weight flow of entrained atmospheric air entering feed funnel with feed, lbs/sec.
Vl = Velocity of entrained air in funnel throat, ft/sec.
a ; V2 = Average velocity of W leaving mixing tube, ft/sec.
g = Gravitational constant, 32.2 ft/sec.
1~956g7 Al = Funnel throat area, sq. ft.
A2 = Area of mixing tube, sq. ft.
P1 = Ambient air pressure = 0 lbs/ft2gage.
P2 = Differential furnace atmosphere pressure above ambient air pressure, lbs/ft gage.
This reactor feed system, installed in a reactor located at an elevation of 1000 feet, operates with an entrained air velocity (Vl) of 20 ft/sec. through the funnel throat and 4psig aspirator air pressure available at the jet nozzle entrances, lo which produces a jet velocity of about 660 ft/sec. ~he amount of aspirating air required is 0.9 lbs/sec; this produces a force of 17.5 lbs. which exceeds and overcomes the 17.1 lbs (~ F) of back pressure and allows a slight positive flow of entrained air through the funnel throat. Sixteen aspirating nozzles with 15" diameter holes, having rounded approaches to provide smooth airflow, are provided to accommodate the o.9 lbs/sec of aspirating air. The sixteen nozzles are arranged in a circle surrounding the funnel throat. The system operates successfully to permit feeding while preventing blow-back from the reaction chamber.
In Figures 4 and 5 there is illustrated a modified form of the invention, in which the feed is introduced through the side wall of a fluid bed reactor rather than through the roof of t`ne unit. The feed device is known as a "slinger" feeder for the reason that the feed is thrown through an opening in the wall of the reactor, above bed level, and is deposited and distributed well within the reaction chamber. Thus, within the slinger housing 77 a high speed endless belt 81 extends about the pulleys 82 and 83, at least one of which is a drive pulley.
, - , ~-S-1958 A feed, which may be a dry ore, is introduced into the receiving port 73 adjacent the rotating feed wheel 85. The feed enters pockets 89 in feed wheel 85 formed by the radiating elements 87. Feed wheel 85 is rotating at essentially the same speed as belt 81, so that the feed is accelerated by wheel 85 up to belt speed. As the feed wheel 85 rotates, the feed in the pockets of wheel 85 is placed on the rapidly moving belt 81 at essentially belt speed and the feed on belt 81 is then carried to the end of the belt and propelled into the furnace feed inlet 60. If the feed were placed directly on belt 81, in the absence of feed wheel 85, the acceleration of the feed by belt 31 alone would be highly abrasive, causing rapid wear of the belt.
The furnace feed inlet 60 comprises a feed conduit 61, which constitutes the initial passageway for the feed propelled by belt 81, a mixing tube 52 (in this case of rectangular rather than circular cross-section) which provides an open passageway through the furnace wall 12, 12a and an aspirating collar 63 having flared walls which span the distance between the feed conduit 61 and the mixing tube 52. A plenum chamber 42 having wall 43 surrounds the periphery of feed conduit 61 and is connected to air conduit 44 which provides a supply of air to the plenum chamber. Air nozzles 56 are mounted in the wall of the plenum chamber 42 to provide communication between the plenum chamber 42 and the interior of the aspirating collar 63. The air nozzles 56 are mounted at an angle in the wall of the plenum chamber 42 so as to focus on a point well within the mixing tube 52.
US-1958 1 ~ S~ ~ ~
The system of Figures 4 and 5 operates in quite similar fashion to that shown in Figure 2. Thus, the slinger feeder propels feed through feed inlet 61 into mixing tube 52. When the operating conditions within the furnace are such that the pressure wlthin the reaction chamber exceeds external pressure, air is supplied to plenum chamber 42 through conduit 44. This pressurized air is directed by the nozzles 56 into the mixing tube 52 and this airflow effectively seals the feed system against the back pressure within the reaction chamber. Even when feeding is not in progress, the air nozzles can be actuated to seal the opening through the furnace wall when the pressure within the reaction chamber exceeds ambient pressure. Of course, a mechanical closure (not shown) may be provided for use when the slinger feeder is not in operation.
The invention thus presents a method for providing a pressure barrier against the back pressure (~ F) of a reaction chamber having an open feed port. A solid particulate feed is introduced into the feed port, of course entraining a certain amount of air. At the same time, high-velocity gas jets are directed into the feed port, in the direction of feed.
The momentum of the various flow components of the constituents moving through the feed port are related as follows to form a pressure barrier against the back pressure ~F) of the reactor:
WaVa + WlVl _W2V2 ~- ~ F
g g g where the symbols in the equation have the same meaning as described previously.
This novel feed system for a fluid bed reactor is capable of continuously introducing dry feed into the reactor while .. . . : . ' ' , . :
~gS697 providing a pressure barrier to prevent blow-back of feed when the operating pressure of the reactor exceeds ambient pressure.
"Dry feed" as used herein above includes feeds which may contain substantial amounts of moisture, but which are unpumpable.
Although the present invention has been described in conjunction with preferred embodiments, it is to be understood that modifications and variations may be resorted to without departing from the spirit and scope of the invention, as those skilled in the art will readily understand. Such modifications and variations are considered to be within the purview and scope of the invention and appended claims.
... . .
Generally speaking, the sealing means of the present invention is associated with a feed apparatus for a fluidized bed reactor and operates to direct a plurality of jets of gas in the direction of feed flow to resist the back pressure of the reaction chamber into which the feed flows.
More specifically, in the present invention a feed conduit serves to introduce dry feed into the reaction chamber of a fluidized bed reactor through a mixing tube, and a seal against reactor bac~ pressure is effected by a plurality of nozzles which direct air jets into the mixing tube, generally in the direction of feed flow. The pressurized air for the air jets is supplied by an annular plenum chamber which surrounds the feed path and is in communication with the nozzles.
Referring now to the drawings, in Figure 1 there is illustrated a fluidized bed reactor 10 having a metal shell 12.
I'he interior of the reactor 10 is divided into two compartments by a constriction plate 19, with a reaction chamber 14 above the constriction plate and a smaller windbox 16 below the constriction plate. A plurality of tuyeres or perforations pierce the constriction plate 19 and provide communication between the windbox 16 and the reaction chamber 14. In the reaction chamber 14 a body of finely divided particulate solids 18 rests on the constriction plate 19. Air inlet means 22 is provided for the windbox 16 and exhaust conduit 24 is in communication with the reaction chamber 14. A product outlet conduit 26 communicates with the fluidized bed 18 within the reaction chamber 14 for the withdrawal of product. The windbox 16 is provided with a cleanout port 27 for the removal of particulate solids which sift through the tuyeres of the ~5697 constriction plate 14 and accumulate in the lower part of the windbox. The feed means 30 is located on the roof 13 of the fluidized bed reactor and is supported by a cylindrical housing 28 which is fixed to the roof 13.
Turning now to Fig. 2 for a detailed description of feed means 30, it is seen that feed belt 36 is located above feed funnel 32 and turns about pulley 38 50 that it is positioned to deliver a dry feed to funnel 32. The mixing tube 52, which is a cylindrical conduit member extending into reaction chamber 14 having a flared mouth portion 52' is supported by the top surface 29 of the cylindrical housing 28. The feed funnel 32 has its narrow lower exit portion adjacent the mouth 52' of mixing tube 52. A flange 46 is joined to both the lower end of the feed funnel 32 and the flared mouth portion 52' of the mixing tube 52, providing a shoulder between the funnel and the mixing tube and overlying the top surface member 29 to which it is secured. The wall member 43 defines the top and outer periphery of an annular plenum chamber 42 which is positioned about the lower portion of the feed funnel 32. The bottom wall of the plenum chamber 42 is provided by the upper surface of the aforementioned flange 46. The enclosure of the plenum chamber 42 is completed by the inner wall 41 which surrounds the lower end of feed funnel 32. A conduit 44 communicated with the plenum chamber 42. In the flange 46 there are positioned a plurality of nozzle members 56 which communicate between the plenum chamber 42 and the flared mouth portion 52' of the mixing tube 52.
; The structure of the nozzles 56 is more clearly seen in Figure 3 where the flange 46 is shown with the nozzles 56 mounted therein. The nozzles 56 are threaded bolt-like members, 11~95697 each having an axial bore 58 therein. As best seen in Figure 2, the nozzles are positioned about the feed path at an inwardly inclined angle, preferably focused at a point downward from the feed funnel 32 and well within the mixing tube 52.
The fèed means 30 may also be provided with a device for dispersing and evenly distributing the feed issuing from mixing tube 52 over the surface of fluid bed 18. The dispersing device in this case comprises a plurality of gas lines 71 (only one of which is illustrated in Figure 2) which terminate in nozzles lo 78. As the feed enters the reaction chamber 14, the dispersing device is actuated and strong jets of gas (air is very usual) impinge on the feed particles and scatter them over the bed surface. This helps maintain uniform conditions in the bed.
While the pressure barrier as described in connection with the embodiment of Figure 2 is supplied by a plurality of jet nozzles 56, it is evident that a fine, generally annular, slot in the member 46 may be substituted for the nozzles to produce an annular jet stream focused within mixing tube 52.
In operation, the feed belt 36 supplies a dry feed to feed funnel 32 of feed means 30. Under the influence of gravity, the feed falls through feed funnel 32 and into mixing tube 52.
Particularly under start-up conditions, where a roasting process is invo}ved, the pressure within the reaction chamber 14 may substantially exceed ambient pressure, with the consequence that the feed may be blown back and out through the feed funnel.
Under these conditions, air is supplied to plenum chamber 42 through conduit 44, which may be in communication with the same blower system which provides fluidizing air for windbox 16 through conduit 22. Thus, air under pressure is present in US-1958 ~ 7 plenum chamber 42. The pressurized air is ~irected by the nozzles 56 into the mixing tube 52 and this airflow effectively seals the feed system against the back pressure within the reaction chamber.
In a typical application of the invention, a roof-mounted aspirating feed funnel is incorporated in a fluid bed reactor, operating on a dry pyrite feed, wherein the excess freeboard pressure in the reaction chamber is 5 inches water column (0.18 psig). This positive pressure is sufficient to blow noxious gases and substantial amounts of solid fine feed back through the dry feed system. The sealing is effected in this reactor, which has a feed funnel throat of 7-5/8" internal diameter, a mixing tube of 11" internal diameter and experiences a back pressure of 17.1 lbs. force (Q F), by establishing conditions which satisfy the equation where change in system momentum equals the force required to hold back the elevated furnace pressure:
~F = WaVa + WlVl ~ W2V2 A2 (P2 1) g g g ~ F = Back pressure force exerted by furnace atmosphere against outside air pressure, lbs.
Wa = Weight flow of aspirating air, lbs/sec.
Va = Jet velocity of aspirating air, ft/sec.
Wl = Weight flow of entrained atmospheric air entering feed funnel with feed, lbs/sec.
Vl = Velocity of entrained air in funnel throat, ft/sec.
a ; V2 = Average velocity of W leaving mixing tube, ft/sec.
g = Gravitational constant, 32.2 ft/sec.
1~956g7 Al = Funnel throat area, sq. ft.
A2 = Area of mixing tube, sq. ft.
P1 = Ambient air pressure = 0 lbs/ft2gage.
P2 = Differential furnace atmosphere pressure above ambient air pressure, lbs/ft gage.
This reactor feed system, installed in a reactor located at an elevation of 1000 feet, operates with an entrained air velocity (Vl) of 20 ft/sec. through the funnel throat and 4psig aspirator air pressure available at the jet nozzle entrances, lo which produces a jet velocity of about 660 ft/sec. ~he amount of aspirating air required is 0.9 lbs/sec; this produces a force of 17.5 lbs. which exceeds and overcomes the 17.1 lbs (~ F) of back pressure and allows a slight positive flow of entrained air through the funnel throat. Sixteen aspirating nozzles with 15" diameter holes, having rounded approaches to provide smooth airflow, are provided to accommodate the o.9 lbs/sec of aspirating air. The sixteen nozzles are arranged in a circle surrounding the funnel throat. The system operates successfully to permit feeding while preventing blow-back from the reaction chamber.
In Figures 4 and 5 there is illustrated a modified form of the invention, in which the feed is introduced through the side wall of a fluid bed reactor rather than through the roof of t`ne unit. The feed device is known as a "slinger" feeder for the reason that the feed is thrown through an opening in the wall of the reactor, above bed level, and is deposited and distributed well within the reaction chamber. Thus, within the slinger housing 77 a high speed endless belt 81 extends about the pulleys 82 and 83, at least one of which is a drive pulley.
, - , ~-S-1958 A feed, which may be a dry ore, is introduced into the receiving port 73 adjacent the rotating feed wheel 85. The feed enters pockets 89 in feed wheel 85 formed by the radiating elements 87. Feed wheel 85 is rotating at essentially the same speed as belt 81, so that the feed is accelerated by wheel 85 up to belt speed. As the feed wheel 85 rotates, the feed in the pockets of wheel 85 is placed on the rapidly moving belt 81 at essentially belt speed and the feed on belt 81 is then carried to the end of the belt and propelled into the furnace feed inlet 60. If the feed were placed directly on belt 81, in the absence of feed wheel 85, the acceleration of the feed by belt 31 alone would be highly abrasive, causing rapid wear of the belt.
The furnace feed inlet 60 comprises a feed conduit 61, which constitutes the initial passageway for the feed propelled by belt 81, a mixing tube 52 (in this case of rectangular rather than circular cross-section) which provides an open passageway through the furnace wall 12, 12a and an aspirating collar 63 having flared walls which span the distance between the feed conduit 61 and the mixing tube 52. A plenum chamber 42 having wall 43 surrounds the periphery of feed conduit 61 and is connected to air conduit 44 which provides a supply of air to the plenum chamber. Air nozzles 56 are mounted in the wall of the plenum chamber 42 to provide communication between the plenum chamber 42 and the interior of the aspirating collar 63. The air nozzles 56 are mounted at an angle in the wall of the plenum chamber 42 so as to focus on a point well within the mixing tube 52.
US-1958 1 ~ S~ ~ ~
The system of Figures 4 and 5 operates in quite similar fashion to that shown in Figure 2. Thus, the slinger feeder propels feed through feed inlet 61 into mixing tube 52. When the operating conditions within the furnace are such that the pressure wlthin the reaction chamber exceeds external pressure, air is supplied to plenum chamber 42 through conduit 44. This pressurized air is directed by the nozzles 56 into the mixing tube 52 and this airflow effectively seals the feed system against the back pressure within the reaction chamber. Even when feeding is not in progress, the air nozzles can be actuated to seal the opening through the furnace wall when the pressure within the reaction chamber exceeds ambient pressure. Of course, a mechanical closure (not shown) may be provided for use when the slinger feeder is not in operation.
The invention thus presents a method for providing a pressure barrier against the back pressure (~ F) of a reaction chamber having an open feed port. A solid particulate feed is introduced into the feed port, of course entraining a certain amount of air. At the same time, high-velocity gas jets are directed into the feed port, in the direction of feed.
The momentum of the various flow components of the constituents moving through the feed port are related as follows to form a pressure barrier against the back pressure ~F) of the reactor:
WaVa + WlVl _W2V2 ~- ~ F
g g g where the symbols in the equation have the same meaning as described previously.
This novel feed system for a fluid bed reactor is capable of continuously introducing dry feed into the reactor while .. . . : . ' ' , . :
~gS697 providing a pressure barrier to prevent blow-back of feed when the operating pressure of the reactor exceeds ambient pressure.
"Dry feed" as used herein above includes feeds which may contain substantial amounts of moisture, but which are unpumpable.
Although the present invention has been described in conjunction with preferred embodiments, it is to be understood that modifications and variations may be resorted to without departing from the spirit and scope of the invention, as those skilled in the art will readily understand. Such modifications and variations are considered to be within the purview and scope of the invention and appended claims.
... . .
Claims
1. Sealing means for the feeding apparatus of a fluid bed reactor operating on a dry feed, wherein said reactor comprises an enclosure in which a reaction chamber is separated from a windbox by a constriction element, said sealing means comprising a roof-mounted vertical feed funnel arranged to receive feed from a feeding device under the influence of gravity, a mixing tube aligned with said feed funnel comprising an upper flared frusto-conical portion and a lower cylindrical portion open without constriction to the reaction chamber for vertically downward discharge of feed thereinto, the upper end of said flared portion of said mixing tube being concen-tric with and in generally surrounding relation to the lower, narrow, end of said feed funnel, a shoulder element joining said lower portion of said feed funnel to said upper flared portion of said mixing tube, a plenum chamber surrounding said narrow lower portion of said feed funnel at said shoulder element and aspirating means comprising air conduit means for introducing pressurized air into said plenum chamber and a plurality of air nozzles in said shoulder element positioned about said lower portion of said feed funnel, said air nozzles being focused upon a point well within said mixing tube for directing a flow of gas at high speed into said mixing tube in the direction of feed to establish a pressure barrier to resist reactor back pressure.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US81662977A | 1977-07-18 | 1977-07-18 | |
| US816,629 | 1986-01-06 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1095697A true CA1095697A (en) | 1981-02-17 |
Family
ID=25221191
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA303,370A Expired CA1095697A (en) | 1977-07-18 | 1978-05-15 | Aspirating feed funnel for fluidized reactor |
Country Status (7)
| Country | Link |
|---|---|
| JP (1) | JPS5440282A (en) |
| AU (1) | AU522375B2 (en) |
| CA (1) | CA1095697A (en) |
| ES (1) | ES471359A1 (en) |
| IN (1) | IN148382B (en) |
| NZ (1) | NZ187394A (en) |
| ZA (1) | ZA782804B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107955096B (en) * | 2017-11-10 | 2019-11-12 | 仲恺农业工程学院 | Preparation method of high performance liquid chromatography stationary phase |
-
1978
- 1978-05-15 CA CA303,370A patent/CA1095697A/en not_active Expired
- 1978-05-16 ZA ZA00782804A patent/ZA782804B/en unknown
- 1978-05-17 IN IN374/DEL/78A patent/IN148382B/en unknown
- 1978-05-24 AU AU36438/78A patent/AU522375B2/en not_active Expired
- 1978-05-29 NZ NZ187394A patent/NZ187394A/en unknown
- 1978-07-03 ES ES471359A patent/ES471359A1/en not_active Expired
- 1978-07-13 JP JP8565278A patent/JPS5440282A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| AU3643878A (en) | 1979-11-29 |
| ES471359A1 (en) | 1979-01-16 |
| AU522375B2 (en) | 1982-06-03 |
| JPS5440282A (en) | 1979-03-29 |
| IN148382B (en) | 1981-02-07 |
| NZ187394A (en) | 1981-07-13 |
| ZA782804B (en) | 1979-12-27 |
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