CA1173084A

CA1173084A - Feeder/distributor apparatus for granular coal

Info

Publication number: CA1173084A
Application number: CA000391570A
Authority: CA
Inventors: Robert L. Gamble
Original assignee: Foster Wheeler Energy Corp
Current assignee: Foster Wheeler Energy Corp
Priority date: 1980-12-22
Filing date: 1981-12-04
Publication date: 1984-08-21
Also published as: JPS57141312A; ES507816A0; GB2090216A; IE813026L; IE52827B1; GB2090216B; ES8300997A1; NL8105742A

Abstract

A FEEDER/DISTRIBUTOR APPARATUS
FOR GRANULAR COAL
ABSTRACT OF THE DISCLOSURE
A feeder/distributor apparatus for granular coal includes a frame that defines an enclosure having two inlets and one outlet with one of the inlets receiving granular coal from an external source for delivery through the outlet to a fluidized bed combustion reactor. A conveyor is disposed within the enclosure for receiving the granular coal and conveying the coal to the vicinity of the outlet. A discharge hopper assembly is disposed in the outlet for receiving the coal from the conveyor.
The hopper assembly includes a plurality of spaced discharge outlets and a mechanism for dividing the coal into a plurality of streams for introduction into the outlets with each so-formed stream being provided to an inlet of the fluidized bed reactor.
A source of pressurized fluid introduced through the other inlet provides a pneumatic assist to the flow of coal through the outlets and to assist in the supression of coal dust.

Description

11'7~0~

~ FEEDE~/DXSrrE~IBUTOR ~PPA:E~TUS
FOR GRANULAR COAL

B~CKGROUND OF THE INVENTION
-The presen-t invention relateS -to a feeder/distributor apparatus and, more particuIarly, to such an apparatus Eor distributing granular coal and/or limestone from a single s-tream source to a plurality of muItiple outlet streams, which, in turn, feed a fluidized bed combustion reactor.
Many applications exist for a feeder/distributor apparatus which receives a single relatively large stream of granular coal and diviaes the stream into a plurality of muItiple streams for introduction into external equipment such as a fluidized bed reactor. For example, many weigh-belt feeders are on the market for feeding a granular material having a relatively wide particle size range, such as coal and/or limestone, into a fluidized bed boiler or combustor, or the like. However, the great ma]ority of these devices, although providing proper metering and con-trolling of the flow rate of the materials, only discharge the stream of material from a single outlet. Since fluidized bed reactors have nllmerous fuel inlets, for example, 30 to 60 inlets, the single outlet feeders are not suitable for the con-tinuous introduction of metered fuel into a fluidized bed reactor.

SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a feeder/distributor apparatus of the above type in which granular coal covering a relatively wide range of particle sizes is received from a single stream source and discharged through a plurality of muItiple outlets for subsequent intro-duction into the plural inlets of a fluidized bed reactor.

It is a further object of the present invention to pro-vide an apparatus of the above type in which a pneumatic assist ..
.

is provided in c~nnection with -the muItiple outlets of the apparatus to assist the flow of coal through the outle-ts and to assist in the supression of coal dust.
Toward the fulfillment of these and other ob~ects, the present invention contemplates a feeder/distributor apparatus for feeding granuIar coal or a mixture of granular coal and limestone into the inlets of a fluidized bed reactor~ The apparatus comprises a frame defining an enclosure having two inlets and one outlet, with an inlet duct connected relative to the frame and registering with one o~ the inlets for supplying granular coal to the enclosure in a substantially vertical dir-ection. A conveying means within the enclosure receives the coal from the one inlet and conveys the coal in a substantially horizontal direction to the vicinity of the outlet. A discharge hopper assembly extends through the outlet for receiving the coal from the conveying means and defines a plurality of spaced, vertically extending, discharge outlets for discharging the coal in a vertical direction. A means associated with the discharge hopper divides the material into a plurality of streams for introduction into the outlets, with the other inlet located dir-ectly above the discharge hopper. An air duct associated with the other inlet introduces a pressurized fluid flow in a vertical direction downwardly into the coal as it flows through the dis-charge hopper assembly to assist the flow of coal through the outlets.
A source of pressurized fluid is associated with the other inlet for introducing a pressurized fluid into the coal as it flows through the discharge hopper assembly to assist the flow of coal through the outlets and to suppress coal dust. The so-formed plural streams of coal are then conducted to the pluralinlets of a fluidized bed reactor to thereby provide metered and

-2-1)84 controlled in-troduc-tion oE coal into -the reactor.

BRIEF DESCRIPTION OF THE DRAWINGS
-The above brief description, as well as further ob~ects, features, and ad~antages, of the present invention wl~l be more fuIly appreciated by reference to the following detailed description of a presently preferred but nonetheless illustrative embodiment in accordance with the present invention, when taken in conjunction with the accompanying drawings wherein:
FIG. 1 is a vertical sectional view showing the apparatus of the present invention;
FIGS. 2 and 3 are sectional views taken along the lines 2-2 and 3-3, respectively, of FIG. l; and FIG. 4 is a horizontal sectional view taken along the line 4-4 of FIG. 1.

DESCRIPTION OF THE PREFERR~D EMBODIMENT
As shown in FIGS. 1 and 2 of the drawing, the reference numeral 10 refers in general to.a frame which defines an enclosure having two inlets 12 and 14 at the upper portion thereof and an outlet 16 at the lower portion thereof. An inlet duct 18 communi-cates with the inlet 12 and is connected to the frame 10. Theduct 18 is adapted to receive granular or particulate coal and/or limestone which may be of varying sizes such as crushed coal of a relatively wide particulate size range or a mixture of crushed coal.and limestone. The duct 18 may be vibrated by an external power source (not shown) in a conventional manner to insure a more even distribution of the granular caal as it flows through the duct and the inlet 12 into the interior of the enclosure defined by the irame 10.

An endless conveyor belt 20 is disposed within the enclo-suredefined by the frame lO.and is entrained about two pulleys22 and 24. The pulley 22 is located below the inlet 12 so that

-3-08 ~

the left end of the upper surface of the belt 20, as viewed in FIG. 1, receives the granular coal from the inlet and the pulley 24 is located over the outlet 16 so that the material is dis-charged from the right end of the upper surface of the belt into the outlet. The pulley 24 is connected to a drive mechanism, such as an electrical motor 26, by a drive belt 28 so that the upper portion of the belt 20 moves in a direction from left to right and therefore transports ~he granular coal from the inlet 12 to the outlet 16.
A discharge hopper assembly, shown in general by the reference numeral 30, is disposed within the outlet 16 and is better shown in connection with FIGS. 3 and 4. In particular, the hopper assembly 30 includes.an inlet mouth portion 30a which is disposed immediately below the discharge end of the conveyor belt 20 for receiving the granuIar coal and a plurality of spaced outlets 30b at the lower portion thereof. A plurality of spaced, parallel flow divider bars 32 are disposed w~thin the discharge hopper.assembly 30 and define a plurality of flow passages communicating with the inlet 30a and the outlets 30b.
As noted from FIG. 1, the cross section of the assembly 30 is tapered from the relatively large inlet 30a to the relatively small outlets 30b, with the f.low divider bars being shaped accordingly. As shown schematically in FIG. 3, the outlets 30b are each connected by.a coal carrying conduit 100 (only four of which.:are shown in broken-line illustration) to a corresponding one of a plurality of coal inlets 102 of a coal-fired fluidized bed reactor 104.
A fluid inlet duct 36 communicates with the inlet 14 of the enclosure defined by the frame 10 and is in vertical alignment with.the discharge hopper assembly 30. The duct 36 is connected to a source (not shown) of pressurized fluid such as air or flue gas and directs the fluid into and through the granular coal flowing through the hopper assembly 30 to provide a pneumatic ~'s~ _4_ assist for the materlal as 1~ passcs thro~c3h the hopp~r assembly 30 and the outlets 30b and to suppress -the form~-tion of coal dus-t consequent to the falling motion of the coal particles.
In operation, the granular coal or a mixture of granular coal and limestone is fed from an external source (not shown) into and through the duct 18 where it enters the inlet 12 of the enclosure defined by the frame 10. The duct 18 may be vibrated to insure a uniform distribution onto the upper surface of the conveyor belt 12 which moves continuously within the enclosure defined by the frame 10 to transport the coal from the area adjacent the inlet 12 to the discharge hopper assembly 30. The pressurized fluid is injected through the inlet 14 from the inlet duct 36 to aid in conveying the coal through the discharge hopper assembly 30. The coal is divided into plural streams or portions by the flow divider bars 32 as it passes downwardly through the assembly 30 and through the outlets 30b for providing several discharge streams into respective conduits 100 and into respective inlets 102 of the fluidized bed reactor 104.
It is thus seen that the device of the present invention enables a uniform discharge of a single source granuIar coal into a plurality of muItiple outlets while insuring a uniform distribution of the material through the entire system.
A latitude of modification, change and substitution is intended in the foregoing disclosure and in some instances some features of the invention will be employed without a corresponding use of other features. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the spirit and scope of the invention herein.

_5_

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A feeder/distributor apparatus for feeding granular coal or a mixture of granular coal and limestone into the inlets of a fluidized bed reactor, said apparatus comprising a frame defining an enclosure having two inlets and one outlet, an inlet duct connected relative to said frame and registering with one of said inlets for supplying granular coal to said enclosure in a substantially vertical direction, conveying means within said enclosure for receiving the coal from said one inlet and conveying the coal in a substantially horizontal direction to the vicinity of said outlet, a discharge hopper assembly extending through said outlet for receiving the coal from said conveying means, said hopper assembly defining a plurality of spaced, vertically extending, discharge outlets for discharging said coal in a vertical direction, means associated with said discharge hopper for dividing said material into a plurality of streams for introduction into said outlets, said other inlet located directly above said discharge hopper, and an air duct associated with said other inlet for introducing a pressurized fluid flow in a vertical direction downwardly into the coal as it flows through said discharge hopper assembly to assist the flow of coal through said outlets.

2. The apparatus of Claim 1 wherein said inlet duct is adapted to be vibrated to facilitate the distribution and flow of coal through said first-mentioned inlet and to said conveying means.

3. The apparatus of Claim 1, wherein said dividing means comprises a plurality of divider bars disposed within said discharge hopper assembly and defining a plurality of flow passages communicating with said outlets.

4. The apparatus of Claim 1, wherein the cross-sectional area of said discharge hopper assembly tapers from a relatively large area at its inlet end to a relatively small area at said outlets.

5. The apparatus of Claim 2, wherein the cross-sectional area of said discharge hopper assembly tapers from a relatively large area at its inlet end to a relatively small area at said outlets.

6. The apparatus of Claim 3, wherein the cross-sectional area of said discharge hopper assembly tapers from a relatively large area at its inlet end to a relatively small area at said outlets.

7. The apparatus of Claim 1, Claim 2 or Claim 3, wherein said granular coal flows by gravity from said inlet duct, through said first-mentioned inlet and onto said conveying means.

8. The apparatus of Claim 4, Claim 5 or Claim 6, wherein said granular coal flows by gravity from said inlet duct, through said first-mentioned inlet and onto said conveying means.

9. The apparatus of Claim 1, Claim 2 or Claim 3, wherein said granular coal flows by gravity from said conveying means to said discharge hopper assembly.

10. The apparatus of Claim 4, Claim 5 or Claim 6, wherein said granular coal flows by gravity from said conveying means to said discharge hopper assembly.

11. The apparatus of Claim 1, Claim 2 or Claim 3, wherein said granular coal has a varying particle size range.

12. The apparatus of Claim 4, Claim 5 or Claim 6, wherein said granular coal has a varying particle size range.

13. The apparatus of Claim 1, Claim 2, or Claim 3, wherein said conveyor means comprises an endless belt, and pulley means for driving said belt.

14. The apparatus of Claim 4, Claim 5, or Claim 6, wherein said conveyor means comprises an endless belt, and pulley means for driving said belt.

15. A feeder/distributor system for dividing a single flow of granulated coal or a mixture of granulated coal and limestone into a plurality of streams and feeding the so-formed streams into the fuel inlets of a fluidized bed reactor, said system comprising:
an enclosure having first and second inlets and an outlet, said first inlet for connection to a first inlet duct for receiving a flow of granulated coal or a mixture of granulated coal and limestone, conveying means within said enclosure positioned therein to receive the granulated coal or mixture from said first inlet and for conveying same towards and into said outlet, a discharge hopper assembly extending through said outlet for receiving the so-conveyed granulated coal or mixture from the conveying means, said dis-charge hopper assembly including means for dividing the coal or mixture received from the conveying means into a plurality of streams and a plurality of discharge outlets for receiving the so-divided streams for discharging same therefrom into conduits, said second inlet located directly above said discharge hopper, said second inlet for connection to a second inlet duct to a source of pressurized fluid so as to introduce a flow of pressurized fluid into the granulated coal or mixture as it flows through said discharge hopper to assist the flow thereof, the direction of flow of the pressurized fluid flow substantially the same as the direction of flow of the granulated coal or mixture, said conduits connected to the inlets of a fluidized bed reactor to introduce the streams of granulated coal or mixture thereto.