US3867261A

US3867261A - Fuel incineration system for calciner

Info

Publication number: US3867261A
Application number: US387474A
Authority: US
Inventors: William E Solano
Original assignee: Salem Corp
Current assignee: Techint Technologies Inc
Priority date: 1973-08-10
Filing date: 1973-08-10
Publication date: 1975-02-18
Anticipated expiration: 1992-02-18

Abstract

A fuel incineration system for a calciner wherein materials undergoing treatment therein evolve volatiles when subjected to a heat treatment and wherein some of these evolved volatiles and carbon particles entrained therein as well as carbon particulates entrained in fluid streams derived from quenching areas associated with the calciner are directed to an incinerator area intermediate the calciner and the flue stack and mixed with air and/or oxygen to combust some of these volatiles and carbon particulates in this area prior to their entry into the flue stack and any unburned volatiles and particulates escaping from the incinerator area are mixed with combustion air admitted at the lower portion of the flue stack to combust in the area of the stack so as to emit from the stack a gas essentially free of any combustible materials.

Description

United States Patent 1191 Solano Feb. 18, 1975 i 1 FUEL lNClNERATlON SYSTEM FOR Assignee: Salem Corporation, Pittsburgh, Pa.

Filed: Aug. 10, 1973 Appl. No.: 387,474

References Cited UNITED STATES PATENTS 2/1972 Calderon 202/263 5/1973 Allred 202/136 10/1973 Allred.... 202/100 10/1973 Allred 1. 202/100 2/1974 Bielski et al. 202/100 I'rinmry hiruminm Wilhur 1.. lluscomb, Jr. Asxixlunl Examiner-D. Sanders [57] ABSTRACT A fuel incineration system for a calciner wherein materials undergoing treatment therein evolve volatiles when subjected to a heat treatment and wherein some of these evolved volatiles and carbon particles entrained therein as well as carbon particulates entrained in fluid streams derived from quenching areas associated with the calciner are directed to an incinerator area intermediate the calciner and the flue stack and mixed with air and/or oxygen to combust some of these volatiles and carbon particulates in this area prior to their entry into the flue stack and any unburned volatiles and particulates escaping from the 'incinerator area are mixed with combustion air admitted at the lower portion of the flue stack to combust in the area of the stack so as to emit from the stack a gas essentially free of any combustible materials.

1 FUEL INCINERATION SYSTEM FOR CALCINER BACKGROUND OF THE INVENTION Furnaces presently employed in the calcination. devolatilization, degasification, etc. of various type materials capable of evolving volatiles when subjected to a heat treatment usually comprise a closed chamber housing a rotating hearth therewithin upon which the materials to be treated are deposited and as the hearth is rotated within the confines of the stationary roof and side walls of the furnace, the materials are subjected to a heat treatment thus causing some of the volatiles from within the materials to evolve and to mix with air and/or oxygen which is fed into the furnace through suitable ports formed in the roof and side walls of the furnace, and to there combust creating an oxidizing atmosphere in the upper portion of the furnace while retaining a reducing atmosphere about the materials on a rotating hearth in the manner broadly set forth above is shown in prior US. Pat. No. 3,227,627 to Asquini and also in US. Pat. No. 3,475,286 to Kemmerer and Buschow. However, in the apparatus shown in the aforementioned patents, no provision is made to treat the gases rising in the stack which leads such gases into the surrounding atmosphere with resultant release into the atmosphere of certain unburned volatiles as well as unburned carbon particulates derived from the materials undergoing treatment within the furnace.

Thus, with the above in mind, it is the primary object of the invention to provide a means whereby any unburned volatiles and carbon particulates entrained therein emanating from the materials undergoing treatment on the hearth of the furnace will be directed into an incineration area intermediate the furnace and the stack or flue and while passing through the said area, air and/or oxygen is fed into this area to combust these unburned gases and carbon particulates and any unburned volatiles and particulates escaping from the incinerator area are mixed with combustion air admitted at the lower portion of the flue stack to combust in the area of the stack so as to prevent the emission of these gases and particulates from the flue of the furnace into the surrounding atmosphere.

' Another object of the invention is to provide a plurality of quenching zones for cooling the processed prodnets and any carbon particulates entrained in the cooling medium directed to an incinerator area positioned intermediate the furnace and the exit flue and while passing through said area, air and/or oxygen is fed therein to combust the said unburned volatiles and carbon particulates and any unburned volatiles and particulates escaping from the incinerator area are mixed with combustion air admitted at the lower portion of the flue stack to combust in this area of the stack to thus prevent the emission of unburned volatiles and combustible particulates into the surrounding atmo sphere before the same leave the stack.

Another object of the invention is to provide a system whereby all unburned volatiles derived from the materials undergoing treatment on the hearth as well as any carbonaceous particulates entrained in the cooling medium leaving the quenching zones for the processed materials will be contained within enclosures which are substantially air tight and to feed such unburned volatiles and carbonaceous particulates to a plurality of incinerator areas where they will be combusted prior to their leaving the stack to thereby prevent a release of these undesirable substances into the surrounding atmosphere.

Another object of the invention is to provide an exhaust fan downstream of a separator means whereby 5 the carbonaceous particulates entrained within the cooling medium employed for quenching the processed materials will be forcibly withdrawn from the quenching area and fed to an incinerator area positioned in advance of the exit flue of the furnace where the same will be combusted so as to avoid the release of these undesirable volatiles and particulates into the surrounding atmosphere.

To the accomplishment of these and such other objects as may hereafter appear, the invention consists of the combination and arrangement of parts herein speciflcally described and illustrated in the accompanying drawings, wherein is shown an embodiment of the invention, but it is to be understood that changes, variations, and modifications may be resorted to which come within the scope of the appended claims.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a view showing schematically the apparatus of the present invention, and,

FIG. 2 is a modified form of apparatus shown in H0. 1 of the drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Before proceeding with a detailed description of the present invention, it should be pointed out that the drawings show a furnace constructed in accordance with the teachings of previously mentioned US. Pat. No. 3,475,286 to Kemmerer and Buschow. This patent shows a structure comprising a substantially air tight enclosure having a rotating hearth mounted therein and on which materials to be subjected to a heat treatment are deposited at an entrance port along the outer periphery thereof and as the hearth rotates, roof mounted rabbles direct the materials to a central outlet where the materials are discharged on to a suitable receiver means. In contrast therewith, the processed materials are peripherally discharged in previously mentioned Asquini US. Pat. No. 3,227,627. However, in both of these previously known structures, use is made of a substantially air tight enclosure for the processing of volatile containing materials therein. The present invention is directed primarily to the containment of any unburned volatiles and any carbonaceous particulates emanating either from within the furnace area or from the quenching zone for the processed materials and to direct such unburned combustibles to incinerator areas which are mounted intermediate the furnace and the outlet flue for the furnace and while in these incinerator areas these combustibles are combusted to thus prevent the emission of unburned volatiles and combustible particulates into the surrounding atmosphere. Thus, it will be appreciated the present inventive concept may be readily adapted to any type furnace structure which is designed to process materials into a substantially air tight enclosure and wherein the processed materials are cooled in quenching areas which are likewise substantially air tight so that any volatiles or carbonaceous particulates emanating from either the materials on the hearth or quenching areas can be contained and led to incinerator areas for the purpose set forth above,

thus obviating the release of contaminants in the surrounding atmosphere.

Referring now to the drawings wherein like reference numerals are employed to designate like parts throughout the several views, numeral designates in general a furnace structure comprising a stationary roof 11, side walls 12, and a rotating hearth 13 mounted for rotation within the confines of the said roof and side walls. The roof, side walls, and rotating hearth are constructed of a suitable refractory and a conventional water, coke, or sand seal 14 is provided between the side walls 12 and the hearth to prevent the escape of volatiles and/or carbonaceous particulates emanating from the materials undergoing treatment into the surrounding atmosphere. If desired, rabbles 15 may be mounted in the roof of the furnace so as to turn over the materials on the hearth and to simultaneously lead the same to an exit area 16 where the same are discharged from onto the hearth to a suitable quenching area. Materials to be treated on the rotating hearth are fed thereto in any known manner as by means of a conventional endless conveyor 17 and hopper 18 having a discharge port which may be adjusted relative to the hearth to thereby enable one to regulate the amount of materials fed onto the hearth. Suitable burner means (not shown) and air and/or oxygen admission ports are provided in the roof and side walls of the furnace and are adapted to function in the manner set forth in the aforesaid Kemmerer and Buschow and Asquini patents which are incorporated herein by reference.

Supported in any suitable manner immediately below the aforesaid exit 16 of the furnace is a discharge table and quencher 19 upon which the processed materials are deposited in any known manner. As can be appreciated, the materials deposited on the table 19 are extremely hot and provision is made to at least partially cool the same while on the table. This can be accomplished by directing a spray of water directly on the materials or, in instances where a direct spray of a cooling medium onto the processed materials is not desirable, other means for quenching the materials on the discharge table and quencher 19 may be employed such as indirect quenching, or the like. However, in order to contain and prevent any cooling medium and impurities or combustible particulates contained therein from escaping into the surrounding atmosphere, a shroud of suitable construction completely encloses the table and a suitable conduit extends from the shroud to a suitable source of vacuum whereby all of the cooling medium and particulates entrained therein are withdrawn from within the shroud for further processing in a manner to be more fully described hereinafter.

A conduit 20 extends from the receiving table and quenching area 19 to an admission port 21 provided in a second quenching zone 22 which is in the nature of a substantially air tight enclosure, again, to prevent the release into the surrounding atmosphere of any contaminants in the charge of materials being fed into the said quencher 22. A plurality of air directing conduits 23 are in communication with the quencher 22 and derive their air for cooling the materials within the quencher 22 from a blower 24. Suitable valves are interposed in the conduits 23 in order to regulate the amount of air directed into the quencher.

An exit 25 is provided in the quencher 22 and is adapted to deliver the cooled materials onto a conveyor of known structure shown generally at 26 thence to a suitable receiver means (not shown). A plurality of exit conduits 27 extend from the quencher 22 and connect through a suitable valving arrangement to the conduit leading from the table and quencher 19 which extends to a separator means such as a cyclone shown generally at 28 which is designed to operate in a manner to be more fully described hereinafter.

Mounted on the roof of the furnace is an exit passage for the waste gases from within the furnace and this passageway leads to the conventional vertically extendingflue stack shown generally at 29. Intermediate the flue stack and the roof mounted outlet aforesaid is an area designated as an incineration area 30. Within this area unburned volatiles emanating from the materials undergoing treatment on the hearth as well as any carbonaceous particulates contained in any of the effluent from the quenching zones are combusted in a manner to be described hereinafter. Extending within the incineration area 30 are a plurality of air and/or oxygen admission ports 31 which lead through suitable conduits to a blower 32 of conventional construction. Mounted at the bottom of the exit flue or stack 29 is an air distributing conduit 33 which derives air from blowers 24 and/or 32 or from any other source. To prevent the release or emission of unburned volatiles and combustible particulates into the surrounding atmosphere, a second incineration area 30' is provided at the lower end of the stack 29. The forcing of air and/or oxygen into the

admission ports

34 and 35 formed in the roof and side walls of the furnace is by way of a suitable conduit extending therefrom and extending to the blower 24. Suitable valving arrangements are provided in the aforesaid conduit in order to enable one to regulate the amount of air and/or oxygen fed to the furnace in order to maintain the desired degree heat temperature therein to properly process the materials undergoing treatment on the hearth. interposed in the conduit leading from the separator 28 and a waste gas inlet 36 extending into the incineration area 30 is a blower 37 which is designed to operate to effect the desired results in a manner to be more fully described hereinafter.

Thus far, there has been described an apparatus and components employed in conjunction therewith for the treatment of materials which yield volatile matter when subjected to a heat treatment where such materials are fed into a substantially air tight enclosure and following the processing thereof within the enclosure are discharged onto a shrouded delivery table where the same are partially quenched and thence to a final cooling area.

The system is designed to operate as follows: With materials undergoing treatment on the hearth as aforesaid,

blowers

24, 32, and 37 are turned on and air and- /or oxygen required to support combustion within the furnace is supplied thereto from the blower 24 which can simultaneously feed air to the quencher 22 and to the base of the stack 29. The valves in all of the conduits leading to the aforementioned will be adjusted to deliver the proper amount of air to provide for the efficient operation of the system. Processed materials delivered to the delivery table will be initially cooled as by directing a spray of water directly thereon, or, as aforesaid, the materials may be initially cooled by utilizing an indirect heat exchange means. With the blower 37 in operatiion, any gases and carbon particles contained therein will be drawn away from the table or quench area and fed into a separator 28 where the heavier particles therein entrained will be caused to settle to the bottom of the separator whereas the lighter constituents together with the fluid medium will be directed to the incinerator areas. as aforesaid, for combustion in these areas of the apparatus. Initially cooled materials will be fed to a second cooler or quenching zone designated at 22 and while in this area, the same will be subjected to a further cooling period by the air which is being fed thereto from the fan 24. The cooling air will exit from the quenching zone 22 through exit ports 27 and will have entrained therein carbonaceous particulates and since the exit ports for the quencher 22 are in communication with the exhaust fan 37, the same will be drawn through the aforesaid separator for removing the heavier particles therefrom and the lighter components along with the gases will be directed to the incinerator areas of the furnace. The combined streams, that is, the effluent from the first cooling zone together with the cooling air in the second cooling zone along with any carbonaceous particulates contained therein are fed to the incineration areas as aforesaid. Upon entering into the incineration area 30, the combined streams are caused to comingle with air and/or oxygen which is fed therein by means of a blower 32. The comingling of the incoming streams of fluids will cause any unburned volatiles and any carbonaceous particulates in the stream to combust in this area of the furnace and to exit through the stack 29. To prevent the release or emission of unburned volatiles and combustible particulates into the surrounding atmosphere,

nace, as aforesaid, the fan 24 will supply a flow of air to the air distributor pipe 33 located at the lower end of the stack 29 to effect a cooling and/or final combustion of the uprising relatively clean exhaust gases. Should there be any unburned volatiles and or carbonaceous particulates in the stream of gases emanating from the incinerator area 30, the combustion air fed to the area 30 through the conduits leading from

fan blowers

24, 32 will mix with these unburned volatiles and carbon particulates to effect a combustion thereof at that position of the exhaust flue or stack 29, thus insuring for the release into the surrounding atmosphere exhaust gases free of any combustible components therein. On the other hand, should all of the volatile matter and combustible particulates be burned in the first incineration area 30, then the air which is fed to air distributing conduit 33 shall serve to cool the uprising gases in the stack 29. The amount of air fed by the blowers 24 and/or 32 or from any other source to the

incinerator areas

30, 30 may be regulated through suitable valving arrangements in the conduits leading from the blowers to the admission ports. However, sufficient air should be supplied to these areas of the furnace as to insure the maintenance ofa degree heat temperature as will insure the combustion in the incinerator areas of any and all combustible materials contained in the unburned volatiles emanating from the materials undergoing treatment on the hearth as well as any unburned volatiles and carbonaceous particulates contained in the stream of gases emanating from the cooling zones. It should be pointed out that the air admission ports formed in the roof and side walls of the furnace will be so constructed as to avoid a direct stream of air from contacting the materials undergoing treatment on the hearth so as to avoid as much as possible the entrainment of particulates in the unburned volatiles seeking an exit from the furnace through the stack, but, notwithstanding such precaution, should any carbonaceous particulates be entrained in such unburned volatiles seeking exit through the furnace flue, such combustible matter will be burned in the incinerator areas and not allowed to exit through the furnace flue which would result in contamination or pollution of the surrounding atmosphere.

The manner in which all of the system effluents are contained during the processing of materials in the manner described above results in a system which will not expose any of the combustible gases produced thereby as well as any combustible particulates contained therein to being discharged into the surrounding atmosphere thereby avoiding the pollution thereof.

While I have shown and described a present preferred embodiment of the invention and have illustrated a present preferred manner of practicing the same, it is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied and practiced within the scope of the following claims.

I claim:

1. A fuel incineration system for a calciner comprising heat treating volatile evolving materials within a substantially air tight enclosure having a flue stack for directing gases fed thereto from said enclosure into the atmosphere, a substantially air tight passageway for the feed of hot processed products from said enclosure to a substantially air tight quenching area, subjecting said processed products to a cooling operation while in said quenching area, a substantially air tight conduit extending from said quenching area to an incinerator area positioned intermediate the said enclosure and said flue, combusting in said incinerator area unburned volatiles and carbonaceous particulates emanating from said enclosure and from said quenching area to thereby exit from said flue a gas substantially free of any air contaminants.

2. The system recited in claim 1 wherein a plurality of quenching areas are provided for the cooling of the processed products.

3. The system recited in claim 2 wherein a substantially air tight passageway is provided for the delivery of said processed products from a first quenching area to a second quenching area.

4. The system recited in claim 1 wherein a blower is mounted in the conduit extending between the said quenching area and the said incinerator.

5. The system recited in claim 4 wherein a separator means is mounted in the conduit extending between the said quenching area and said incinerator area.

.6. The system recited in claim 1 wherein a second incineration area is provided at the base of the flue stack.

7. The system recited in claim 6 wherein air is directed into the second incineration area to combust any volatiles and carbonaceous particulates emanating from a first incineration area.

8. The system recited in claim 6 wherein air is admitted into the second incineration area to cool the uprising gases in said flue stack.

9. An apparatus for combusting unburned carbonaceous materials entrained in a stream directed for exit through a flue stack for a furnace, comprising,

a substantially air tight enclosure having a roof, side walls, and a hearth mounted for rotation within the said enclosure,

means for feeding on said hearth materials capable of evolving volatiles when subjected to a heat treatment,

subjecting said materials to a heat treatment while on said hearth,

a passageway extending between said enclosure and said flue stack,

an incineration area formed in said passageway and at the lower end of said flue stack,

a conduit extending from said enclosure to a substantially air tight enclosure forming a quenching area for the materials fed thereinto from the said hearth,

subjecting said processed materials to a cooling medium while in said quenching area,

means for exhausting said cooling medium from said quenching area and directing the same to said incinerator areas through a substantially air tight conduit extending between said quenching area and said incinerator,

air admitting ports extending into said incinerator areas for combusting unburned volatiles and carbonaceous particulates contained in said cooling medium as well as any unburned volatiles and carbonaceous particulates emanating from the materials undergoing treatment on the hearth to thereby exit through the outlet of said flue stack a gas substantially devoid of any air contaminants therein.

10. The structure recited in claim 9 wherein a blower fan is provided in the conduit extending between the said quenching area and the said incinerator.

11. The structure recited in claim 9 wherein a plurality of quenching areas are provided, and wherein substantially air tight conduits extend from each of said quenching area to the next adjacent quenching area.

12. The structure recited in claim 9 wherein a separator means is interposed in the conduit extending from the said quenching areas to the said incinerator to separate the heavier particulates entrained in the cooling medium withdrawn from the said quenching areas.

13. The structure recited in claim 9 wherein a blower means is employed for forcing a stream of air into the said incinerator areas to combust all unburned volatiles and carbonaceous particulates entrained in the stream of coolant medium directed thereinto.

14. An apparatus for combusting unburned carbonaceous materials entrained in a stream directed for exit through a flue stack for a furnace, comprising,

a substantially air tight enclosure having a roof. side walls, and a hearth mounted for rotation within the said enclosure,

subjecting said materials to a heat treatment while on said hearth,

a passageway extending between said enclosure and said flue stack,

an incineration area formed in said passageway.

a conduit extending from said enclosure to a substantially air tight enclosure forming a quenching area for the materials fed thereinto from the said heartl'n subjecting said processed materials to a cooling medium while in said quenching area,

means for exhausting said cooling medium from said quenching area directing the same to said incinertor area through a substantially air tight conduit extending between said quenching area and said incinerator,

air admitting ports extending into said incinerator area for combusting unburned volatiles and carbonaceous particulates contained in said cooling medium and said gases rising from above the said hearth,

air admitting ports extending into the lower portion of the said flue stack for cooling the gases rising therein to thereby exhaust from the flue stack and into the atmosphere a cooled and volatile and carbonaceous particulates-free gas.

Claims

6. The system recited in claim 1 wherein a second incineration area is provided at the base of the flue stack.

9. An apparatus for combusting unburned carbonaceous materials entrained in a stream directed for exit through a flue stack for a furnace, comprising, a substantially air tight enclosure having a roof, side walls, and a hearth mounted for rotation within the said enclosure, means for feeding on said hearth materials capable of evolving volatiles when subjected to a heat treatment, subjecting said materials to a heat treatment while on said hearth, a passageway extending between said enclosure and said flue stack, an incineration area formed in said passageway and at the lower end of said flue stack, a conduit extending from said enclosure to a substantially air tight enclosure forming a quenching area for the materials fed thereinto from the said hearth, subjecting said processed materials to a cooling medium while in said quenching area, means for exhausting said cooling medium from said quenching area and directing the same to said incinerator areas through a substantially air tight conduit extending between said quenching area and said incinerator, air admitting ports extending into said incinerator areas for combusting unburned volatiles and carbonaceous particulates contained in said cooling medium as well as any unburned volatiles and carbonaceous particulates emanating from the materials undergoing treatment on the hearth to thereby exit through the outlet of said flue stack a gas substantially devoid of any air contaminants therein.

14. An apparatus for combusting unburned carbonaceous materials entrained in a stream directed for exit through a flue stack for a furnace, comprising, a substantially air tight enclosure having a roof, side walls, and a hearth mounted for rotation within the said enclosure, means for feeding on said hearth materials capable of evolving volatiles when subjected to a heat treatment, subjecting said materials to a heat treatment while on said hearth, a passageway extending between said enclosure and said flue stack, an incineration area formed in said passageway, a conduit extending from said enclosure to a substantially air tight enclosure forming a quenching area for the materials fed thereinto from the said hearth, subjecting said processed materials to a cooling medium while in said quenching area, means for exhausting said cooling medium from said quenching area directing the same to said incinertor area through a substantially air tight conduit extending between said quenching area and said incinerator, air admitting ports extending into said incinerator area for combusting unburned volatiles and carbonaceous particulates contained in said cooling medium and said gases rising from above the said hearth, air admitting ports extending into the lower portion of the said flue stack for cooling the gases rising therein to thereby exhaust from the flue stack and into the atmosphere a cooled and volatile and carbonaceous particulates-free gas.