CA1065194A - Low pollution incineration of solid waste - Google Patents
Low pollution incineration of solid wasteInfo
- Publication number
- CA1065194A CA1065194A CA312,919A CA312919A CA1065194A CA 1065194 A CA1065194 A CA 1065194A CA 312919 A CA312919 A CA 312919A CA 1065194 A CA1065194 A CA 1065194A
- Authority
- CA
- Canada
- Prior art keywords
- fluidized bed
- air
- chamber
- bed
- solid waste
- 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
Landscapes
- Fluidized-Bed Combustion And Resonant Combustion (AREA)
Abstract
Abstract of the Disclosure An incinerator system and method wherein pieces of solid waste, such as fragments of wood, are conveyed in such a fashion as to become disposed within a fluidized bed of an incinerator vessel. Preferably the solid waste particles are caused to be somewhat homogeneously dispersed within the fluidized bed. The solid waste particles may be "pre-dried"
or moisture may be added to the particles prior to deposition in the fluidized bed for optimum results, depending upon circumstances. In one embodiment, the fluidized bed is situated above an air delivery chamber at the bottom of the vessel and supports combustion of the solid waste particles in the fine granular material comprising the fluidized bed.
The fine granular material is supported by a perforated plate.
The air delivery system channels high temperature air into an up through the fluidized bed until operating temperature is reached and so channels ambient air thereafter. Volatile matter given off by combustion of the solid waste particles in the fluidized bed is burned smokelessly in the vapor space immediately above the bed.
or moisture may be added to the particles prior to deposition in the fluidized bed for optimum results, depending upon circumstances. In one embodiment, the fluidized bed is situated above an air delivery chamber at the bottom of the vessel and supports combustion of the solid waste particles in the fine granular material comprising the fluidized bed.
The fine granular material is supported by a perforated plate.
The air delivery system channels high temperature air into an up through the fluidized bed until operating temperature is reached and so channels ambient air thereafter. Volatile matter given off by combustion of the solid waste particles in the fluidized bed is burned smokelessly in the vapor space immediately above the bed.
Description
lO~S1~9~
BACYGROUND
Field of Invention The present invention relates generally to incinera-tion or pyrolysis of waste and more particularly to smokeless, low pollution fluidized bed combustion of pieces of solid organic waste, such as wood waste~ municipal refuse~ industrial solid waste and livestock refuse, and volatile matter given off by the solid waste and, lf desired, incineration of carbonaceous residue produced by combustion of the solid waste. More specifically, the present invention relates to a novel bed nozzle system for maintaining good quality fluidized bed properties allowing tramp material to be isolated and removed, to a novel vortex generator system for increasing the residence time of any solid waste particle and for centrifuging particles from the fluidized bed and solid waste particles, to no~el bed material and to a novel air ~et in~ection of fuel into the burner.
Prior Art The known prior art comprises expensi~e incineration of solid waste which results in substantial atmospheric pollution and which are difficult and costly to maintain.
Substantial supervision is required and combustion is often incomplete due to a number of factors including inadequate residence time. Also, the fine particles from the fluidized bed are often carried away in the exhaust.
BRIEF SUMNARY AND OBJECTS ~F THE INVENTION
Aa essentially pollution-free fluidized bed incinera-tion or pyrolysis system and methot wherein solid pieces of waste are coneinually fed, preferably by an air jet in~ection system so as to become deposited within a fluidized bed near the bott~m of a combustion vessel. The pieces of solid waste are preferably distributed so as to be somewhat homogeneously -3- ~
10~519~
clisposed withln the fluidi~ed bed, uniquely comprising olivine.
A novel vortex 8enerator system is provided with or without vertical stagnation columns causing air to lift from the fluidized bed in a vortical pattern wbich increases the residence time of particles disposed in the vapor space above the fluidized bed allowing for the same to be consumed or returned due to centrifugal force to the bed. In like fashion, fine particles from the fluidized bed per se initially lifted by the air flow within the vapor space are centrifuged and returned to the bed.
Uniquely, bed nozzles are disposed above an air diseribution system comprising air ducts and nozzles to which fluidizing air is uniformly channeled. The fluidized bed is disposed above the air distribution system, creating a zone at the bottom of the fluidized bed adapted to receive tramp material in a continuous fashion during operation thereby obviating what would otherwise be a material decrease in desirable bed properties during operation. A system is provided for COn-t~nuously removing the tramp material from said zone; it is contemplated that some bed material will also be continuously removed from said zone, segregated from the tramp material and returned to the bed. Back flow of the particulate matter of the fluidized bed is prevented, air flow into the bed through the ducts and through the bed nozzles being evenly distributed, and erosion of the duct work by the particulate matter is prevented. Initially, temperatures within the system may be set by a start-up heater and elevated to full incineration capacity by combustion of the volatiles within the vapor air space. Either complete incineration or recovery of a car-bonaceous residue may be accomplished depending upon temperatures 30 of operation. The exhaust from the vessel may be processed to other mechanisms for removal of any residual solid particles in one or more known ways.
-10t~519~
In accordance with one broad aspect, the invention ., r~ tes to an incineration system comprising: a generally cylindrical incineration chamber; a fluidized bed located withi,n the chamber with a vapor space defined in the chamber above the fluidized bed; means causing combustible waste to be introduced into the incineration chamber and dispersed within the fluidized bed; effluent opening means above the vapor space .
communicating exhaust from the interior of the chamber; influent air means communicating air into the interior of the chamber and being disposed centrally above the fluidized bed directing said air centrally downward against the fluidized bed and causing air to elevate within *he chamber as an annulus adjacent the wall of the chamber; auxiliar~ influent air means communicating air : into the interior of the chamber adjacent the wall of the chamber within the vapor space with at least the major component of air displaced therefrom being tangential to the wall when introduced into the chamber; whereby a gradually elevating annular vortex of air is created whereby fine particles are centrifuged from the vapor space to the fluidized bed and vapor space residence time for any residual particles is increased accommodating complete combustion.
In accordance with another aspect, the invention relates to a method of low pollution eliminating of solid particles vaporized during incineration, the steps of:
elevating the temperature of a confined fluidized bed to an ' order of magnitude capable of supporting combustion;
: continuously causing pieces of solid waste to become embedded within the confined fluidized bed; impinging influent air centrally downward against the fluidized bed within the ~ 30 confinement; combusting the solid waste within the fluidized bed and volatizing the volatile matter contained within the solid waste into the vapor space between the top of the fluidized ~ -4A-l~;S~
bed and the top of the confinement; ater-burning the volatile matter in the vapor space extending substantially above the fluidized bed; causing an annulus of air to be vortically circulated around the impinging influent air throughout substantially the entirety of the vapor space within the confinement to increase residence time, prevent channeling and centrifuging airborne solid particles causing at least some of said particles to return to the bed by force of gravity.
'' 10 .
..
~0 , ,, 10~519~
Accordingly, it i~ a primary ob~ect of the present inVentiOn to provide a novel incinerating or pyrolysis system and method.
Another paramount ob~ect of the present invention is to provide a novel fluidized bed arrangement including bed nozzles for use in incineration and pyrolysis.
A further dominant object is the provision of a novel vortex generator system to increase residence time of solid waste particles in a vapor zone above a fluldized bed in a vessel thereby accommodating full combustion of such particles either in the vapor space or by returning the same to the fluidized bed through centrifugal force, and preventing loss of fine particles from the fluidized bed.
An additional principal ob~ect is the provision of a novel air ~et fuel in~ection system for use in solid waste incineration or pyrolysis.
Another primary object is the provision of a unique system for isolating and removal of tramp material during incineration or pyrolysis.
A further important object is the provision of a novel system for recycling and purifying bed material.
One more significant ob~ect is the provision of a novel bed material comprising olivine in a fluidized bed for incineration or pyrolysis.
These and other objects and features of the present inventi~n will be apparent from the following detailed description taken in reference to the accompanying drawings.
BRIEF DESCRIPT10~ 0F THE DRAWINGS
. . -- ~
Figure 1 is an elevational schematic of an incinerator in accordance with the present invention, with parts broken 10~519'~
away for the purpose of clarity;
F$gure 2 is a plan view of the auxiliary air and nozzle system for creating aD overfire air vortex;
Figure 3 is a view taken along line 3-3 of Figure 2;
Figure 4 is an enlarged elevational view of a presently preferred noz~le, four of which are shown in Figure 2;
Figure 5 shows an enlarged fragmentary elevation of one presently preferred fluidized bed nozzle configura-tion for isolation of tramp material;
Figures 6-9 show in elevation with parts broken away for clarity various fluidized bed nozzles which may be used in conjunction with the configuration of Figure 5;
Figure 10 is a vertical cross-sectional view of a second presently preferred embodi~ent of the present in~ention;
Figure 11 is a cross-sectional view in plan of the embodiment of Figure 10 taken along lines 11-11 of Figure 10;
Figure 12 is a cross-sectional view taken along lines 12-12 of Figure 11; and Figure 13 is an enlarged elevational view of the fuel in~ection system of the embodiment of Figure lOo DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
~ Reference is now made to the embodiment illustrated in : Figures 1-9 wherein like numerals are used to designate like parts throughout. Broadly~ the solid organic waste low pollu-tion incinerator, generally designated 10~ comprises apparatus for continually delivering fuel which may comprise pieces of solid ~as~e 12 to an incineration or pyrolysis site.
Thereafter, the pieces of solid waste 12 are caused to become somewhat homogeneously distributed within a fluidized bed ; 30, disposed near the bottom of an incineration vessel 26.
While any conveyance may be used to so deposit the sDlid waste ~O~Slg ~
pieces 12 within the fluidized bed 30, including the direct injection of the pieces into the bed, a box conveyor 14 is illustrated in Figure 1. Conveyor 14 comprises a conveyor belt 16 conventionally driven and displaced around either roller 17 whereby the solid waste pieces 12 fall into the vessel and are distributed by an impact cone 19 which is mounted on a column 21 and in turn supported by a cross member 23.
Mechanisms may be used in conjunction with the box conveyor 14 to meter the rate at which solid wast~e pieces are fed into the incinerator. As a consequence, the pieces of solid waste 12, which, by way of example, may comprise wood waste and like stoc~ refuge, are caused to be evenly distributed and embedded within the fluidized bed 30.
Depending upon the particular material and circum-stances, pieces of solid waste 12 may be pre-dried beore being fed into the incinerator, or water may be added thereto prior to or slmultaneously with displacement into the incinerator. In any event, said pieces are subject to high temperature combustion9 with or without carbonaceous residue~ depending upon operating temperature, oxygen available and mode of operation.
A vapor zone 34, immediately above the fluidized bed 30 comprises a site where volstile matter, released by the pieces of solid waste 12 during combustion occurring in the fluidized bed, are in turn combusted spontaneously or by separate ignition means. Since the process is con-tinuous, the heat of combustion within the fluidized bed and ~he heat of combustion in the vapor space complement each other so that operating temperatures are readily maintained, once established.
An air delivery system 32 drives air under pressure as indicated by arrows 40 from the source of pressurized ~o~
air 25 upward into the fluidized bed 30 adequate to establish and sustain the requisite combustion. Initially, high temperature air under pressure i~ used, being obtained from a conventional air heater 42. Once the fluidized bed 30 has reached the desired operating temperature or slightly below that temperature, the air heater 42 is switched off and a high capacity squirrel cage blower 25 or the like continues to deliver ambient air to the fluidized bed Blower 44 is driven by motor Ml.
Gaseous exhaust passes from the vessel 26 through an effluent conduit 50 either directly into the atmosphere where the parts per million of solid particles in the exhaust do not exceed maximum limits permitted for the operating location in question, or through auxiliary mechanisms where such solid particle content is adequately reduced.
If and to the extent desired, heat may be recovered from the vessel 26 using a conventional b~iler or the like.
Also, the temperatures within the vessel 26 may be controlled by selecting an amount of moisture to be introduced into the vessel during operation.
With greater specificity, the fluidized bed vessel 26 comprises a right circular cylinder of sheet metal which is preferably insulated by refractory material along the inside thereof. A horizontally disposed top 27, also preferably insulated in the s~me fashion, seals ~he vessel except for influent air, influent solid waste pieces and effluent exhaust.
~or greater detail in the manner ~n which the vessel 36 and auxiliary features may be fabricated and assembled, reference may be had to my Can~dian patent ~o. 990,145 issued J~ne 1, 1976.
lO~;Sl9 1 Openings 29, 31 and 33 acco~modate introduction of solid waste pieces, introduction of influent air, and expulsion of exhaust, respectively.
The air delivery system 32 discharges air under pressure received from blower 25 along conduit 35 through opening 37 into air feed chamber 39. The air under pressure from chamber 39 is forced through apertures 41 and 43 in grid plate 45 directly into the fluidized bed and through bed nozzles 47, respectively. Preferably, adequate struc-tural support for grid plate 45 is provided by conventionalstructural steel members (not shown). The grid plate 45, preferably of mild steel, is uniformly perforated by said apertures 41 and 43 in evenly arranged X and Y rows. The apertures are sized so as to readily permit influent air from the air delivery system 32 to pass through the plate 45 into the remainder of the fluldized bed 30, causing an even distribution of air. Cover caps 51 of the nozzles 47 are disposed essentially at the interface between the materials comprising the fluidized bed 30 and a tramp zone 53 whereby passage of the particulate matter of the fluidized bed through apertures 43 is prevented. In like fashion, plates 55 are preferably used to cover the apertures 41 for the same purpose as some of the tramp zone 53 will comprise particulate matter from the fluidized bed.
The fluidized bed 30 comprises a layer 59 of fine granular particulate matter, which preferably uniquely comprises eight to thirty mesh olivine sand, r~sts upon the perforated plate 45 and receives therein the previously mentioned solid waste pieces 12, causing incineration or pyrolysis thereof, depending upon selected operating temperatures and other variables. It is preferred that olivine lOf~Sl9'~
sand of eight to thirty mesh size ran8e be used to form par-ticulate layer 59.
Surprisingly, research and development has established that a bed material comprising olivine sand results in superior performance both in reducing the tendency to fuse and cake and in the rate of particle breakdown and elutriation of the bed material, when compared with bed materials heretofore used.
Olivine sand is a mineral of small particle size identified by the chemical compound (Mg,Fe) SiO4. More specifically, olivine sand is available from the Olivine Corporation of 1015 Hilton Avenue, Bellingham~ Washington 98225 and has either of the following compositions:
Mountain Quarry Reef Point Quarry Silica (SiO ) 40.08% 42.2Z
Iron (Fe O3~ 8.82 6.4 Alumina ~Al O3) 2.22 ---Calcium Oxi~e (CaO) .24 18.4 Magnesia (NgO) 48.39 31.2 Sodium (Na 0) 0.04 Potassium ~K2O) 0.05 .
Chromite 0.2 99.89 98.4 The size analysis of olivine sand is reported as follows:
Retained on Weight U.S. Screen Size Percent #16 34.1 #20 56.0 #30 9.2 #40 0.4 pan 0.3 The specific gravity of olivine is 3.22 to 4.39 and with a hardness rating of 6.5 ~o 7Ø It is a rhombic crystalline form and will vary in col~r from olive green to grayish green to a yellowish brown. The material in a particle size varying from a twelve mesh to thirty mesh material is preferred, (U.S. standard gauge screens). It has been found to h.ave a low coefficient of thermal expansion, and is highly fracture resistant to the mechanical and thermal conditions to which it is subjected in the fluidized bed combustion process.
The test results are set forth in the attached copy .
of a publication entitled ~TEST RESULTS OLIVINE SAND as a 10 BED MATERIAL for the FLUID FLAME BURNER", by T.H. Daniels, dated October 15, 1974. .
The entire bed, excluding tramp layer 5S, may be on the order of nine inches to eighteen inches deep.
In respect to the bed nozzles 47 ~Figure 5), it has, surprisingly, been found that suitable bed nozzles, each disposed upon a stand pipe 61 (defining the height of the inactive zone 53) causes non-combustible larger sized material to be continuously removed from the active fluidized bed 30 thereby maintaining good quality bed properties at all times.
It has been found that the apertures 43 in the grid plate 45 must permit enough air flow to allow the particulate matter . of the bed to move upwardly under the force of said air.
The apertures 41 are preferably of smaller size and serve fundamentally to purge a substantial part of the particulate matter of the fluidized bed from the tramp zone 53.
lO~Sl9~
It is to be sppreciated that any one of a number of different types of bed nozzles may be used. Some suitable ~ed nozzles are illustrated in Figures 509. Each is mounted upon the stand pipe 61 and comprises a horizontal top or cover 51. In Figure 5, the cover 51 is disc shaped, is mounted upon a base plate 63 using columns 65, which in combination define a plurality of radially disposed, hori-zontally directed air effluent port 67~ The stand pipe 61 is welded to the base plate 63 at site 69. Each stand pipe 61 is likewise welded at sites 71 to the top of the grid plate 45.
With reference to Figure 6, the cover plate 51 is downwardly configurated to create the horizontally extending .
lip 73, which is welded to the bottom plate 63 and inter-rupted at two locations 180 from esch other to create air discharge ports 75.
In reference to Figure 7, the square cover plate 51 is mounted directly to the top of the stand pipe 61 by four spacers 79 located at each corner and secured at weld sites 77~ with four radially disposed air discharge ports 79 between the four corner spacers 79. Air escaping from the ports 79t is channeled between the bottom surface of top coYer plate 51 and the top surface of a lower square plate 631, the latter having a central aperture through which the stand pipe 61 extends and being welded to the stand pipe at sites 81.
Figure 8 is a further bed nozzle embodi.ment wherein the stand pipe 61 is closed at its upper end by plug 83 which is welded or otherwise suitably secured in position.
An external cap 85 fits around the upper end of the stand lO~Sl9'~
pipe 61 and is likewise secured thereto by weldin~ or the like. The cap 85 has a plurality of outwardly and down-wardly extending bores 87, which are sized and shaped to match apertures 89 disposed in the upper end of the stand pipe 61. Thus, air emitted from the bed nozzle of Figure 8 will be directed radially at an acute angle to the hori-zontal from the bores 87.
The bed nozzle embodiment of Figure 9 illustrates the cover plate 51 being supported upon and welded to 8 plurality of posts 91, the lower end of each post being welded to the interior of the stand pipe 61. The stand pipe 61 is flaired at its upper end 93, causing air expelled therefrom to be displaced generally radially in a horizontal plane beneath the cover plate 51.
A novel vortex generator system is best illustrsted in Figures 2-4. The system provides a source 101 of air under pressure which may be a squirrel cage blower driven by motor N2. It is preferred that motor M2 be a variable speed motor which may be regulated by the operator to control the rate at which air is introduced into the incinerator vessel 26 by the vortex ~enerator system.
Air issuing from the source 101 passes through main conduit 103 issuing into the incinerator vessel 26 through a plurality of discharge sites. The ma~ority of the air from main conduit 103 is displaced into the vessel 26 through nozzle 105 ~7hich downwardly extends into the vessel tightly through opening 31 in the top 27 thereof. Air discharge from the nozzle 105 proceeds as indicated by arrows 107, coming in contact with the top surface of the fluidized bed 30 as a vertical column and being displaced essentially radially outward thereafter. Said influent air~ ~7hich may be preheated as desired~ is elevated in temperature once it reache~ the -10~519~
vicinity of the fluidized bed 30 causing the same to commence to elevate along an annulus disposed between the cylindrical verti~al wall of the vessel 26 and the column of influent air shown at arrows 107.
Air fro~ the main conduit pipe 103 is channeled, as best illustrated in Figures 1 and 2~ by auxiliary conduits 109, 111 and 113 to supply a plurality of vortex nozzles llS. The nozzles 115 may be of any suitable type, the configuration shown in Figure 4 being acceptable. Each nozzle is fitted through the vertical wall of the ~essel 26 at sites 117 at an acute angle in regard to the radius thereof such that air issuing from each nozzle 115, while not tangential initially becomes tangential immediately upon merging with the annulus of air being circulated between the interior surface of the vertical wall of the vessel 26 and the downwardLy directed column of nfluent air 107. This phenomenon is best illustrated in Figure
BACYGROUND
Field of Invention The present invention relates generally to incinera-tion or pyrolysis of waste and more particularly to smokeless, low pollution fluidized bed combustion of pieces of solid organic waste, such as wood waste~ municipal refuse~ industrial solid waste and livestock refuse, and volatile matter given off by the solid waste and, lf desired, incineration of carbonaceous residue produced by combustion of the solid waste. More specifically, the present invention relates to a novel bed nozzle system for maintaining good quality fluidized bed properties allowing tramp material to be isolated and removed, to a novel vortex generator system for increasing the residence time of any solid waste particle and for centrifuging particles from the fluidized bed and solid waste particles, to no~el bed material and to a novel air ~et in~ection of fuel into the burner.
Prior Art The known prior art comprises expensi~e incineration of solid waste which results in substantial atmospheric pollution and which are difficult and costly to maintain.
Substantial supervision is required and combustion is often incomplete due to a number of factors including inadequate residence time. Also, the fine particles from the fluidized bed are often carried away in the exhaust.
BRIEF SUMNARY AND OBJECTS ~F THE INVENTION
Aa essentially pollution-free fluidized bed incinera-tion or pyrolysis system and methot wherein solid pieces of waste are coneinually fed, preferably by an air jet in~ection system so as to become deposited within a fluidized bed near the bott~m of a combustion vessel. The pieces of solid waste are preferably distributed so as to be somewhat homogeneously -3- ~
10~519~
clisposed withln the fluidi~ed bed, uniquely comprising olivine.
A novel vortex 8enerator system is provided with or without vertical stagnation columns causing air to lift from the fluidized bed in a vortical pattern wbich increases the residence time of particles disposed in the vapor space above the fluidized bed allowing for the same to be consumed or returned due to centrifugal force to the bed. In like fashion, fine particles from the fluidized bed per se initially lifted by the air flow within the vapor space are centrifuged and returned to the bed.
Uniquely, bed nozzles are disposed above an air diseribution system comprising air ducts and nozzles to which fluidizing air is uniformly channeled. The fluidized bed is disposed above the air distribution system, creating a zone at the bottom of the fluidized bed adapted to receive tramp material in a continuous fashion during operation thereby obviating what would otherwise be a material decrease in desirable bed properties during operation. A system is provided for COn-t~nuously removing the tramp material from said zone; it is contemplated that some bed material will also be continuously removed from said zone, segregated from the tramp material and returned to the bed. Back flow of the particulate matter of the fluidized bed is prevented, air flow into the bed through the ducts and through the bed nozzles being evenly distributed, and erosion of the duct work by the particulate matter is prevented. Initially, temperatures within the system may be set by a start-up heater and elevated to full incineration capacity by combustion of the volatiles within the vapor air space. Either complete incineration or recovery of a car-bonaceous residue may be accomplished depending upon temperatures 30 of operation. The exhaust from the vessel may be processed to other mechanisms for removal of any residual solid particles in one or more known ways.
-10t~519~
In accordance with one broad aspect, the invention ., r~ tes to an incineration system comprising: a generally cylindrical incineration chamber; a fluidized bed located withi,n the chamber with a vapor space defined in the chamber above the fluidized bed; means causing combustible waste to be introduced into the incineration chamber and dispersed within the fluidized bed; effluent opening means above the vapor space .
communicating exhaust from the interior of the chamber; influent air means communicating air into the interior of the chamber and being disposed centrally above the fluidized bed directing said air centrally downward against the fluidized bed and causing air to elevate within *he chamber as an annulus adjacent the wall of the chamber; auxiliar~ influent air means communicating air : into the interior of the chamber adjacent the wall of the chamber within the vapor space with at least the major component of air displaced therefrom being tangential to the wall when introduced into the chamber; whereby a gradually elevating annular vortex of air is created whereby fine particles are centrifuged from the vapor space to the fluidized bed and vapor space residence time for any residual particles is increased accommodating complete combustion.
In accordance with another aspect, the invention relates to a method of low pollution eliminating of solid particles vaporized during incineration, the steps of:
elevating the temperature of a confined fluidized bed to an ' order of magnitude capable of supporting combustion;
: continuously causing pieces of solid waste to become embedded within the confined fluidized bed; impinging influent air centrally downward against the fluidized bed within the ~ 30 confinement; combusting the solid waste within the fluidized bed and volatizing the volatile matter contained within the solid waste into the vapor space between the top of the fluidized ~ -4A-l~;S~
bed and the top of the confinement; ater-burning the volatile matter in the vapor space extending substantially above the fluidized bed; causing an annulus of air to be vortically circulated around the impinging influent air throughout substantially the entirety of the vapor space within the confinement to increase residence time, prevent channeling and centrifuging airborne solid particles causing at least some of said particles to return to the bed by force of gravity.
'' 10 .
..
~0 , ,, 10~519~
Accordingly, it i~ a primary ob~ect of the present inVentiOn to provide a novel incinerating or pyrolysis system and method.
Another paramount ob~ect of the present invention is to provide a novel fluidized bed arrangement including bed nozzles for use in incineration and pyrolysis.
A further dominant object is the provision of a novel vortex generator system to increase residence time of solid waste particles in a vapor zone above a fluldized bed in a vessel thereby accommodating full combustion of such particles either in the vapor space or by returning the same to the fluidized bed through centrifugal force, and preventing loss of fine particles from the fluidized bed.
An additional principal ob~ect is the provision of a novel air ~et fuel in~ection system for use in solid waste incineration or pyrolysis.
Another primary object is the provision of a unique system for isolating and removal of tramp material during incineration or pyrolysis.
A further important object is the provision of a novel system for recycling and purifying bed material.
One more significant ob~ect is the provision of a novel bed material comprising olivine in a fluidized bed for incineration or pyrolysis.
These and other objects and features of the present inventi~n will be apparent from the following detailed description taken in reference to the accompanying drawings.
BRIEF DESCRIPT10~ 0F THE DRAWINGS
. . -- ~
Figure 1 is an elevational schematic of an incinerator in accordance with the present invention, with parts broken 10~519'~
away for the purpose of clarity;
F$gure 2 is a plan view of the auxiliary air and nozzle system for creating aD overfire air vortex;
Figure 3 is a view taken along line 3-3 of Figure 2;
Figure 4 is an enlarged elevational view of a presently preferred noz~le, four of which are shown in Figure 2;
Figure 5 shows an enlarged fragmentary elevation of one presently preferred fluidized bed nozzle configura-tion for isolation of tramp material;
Figures 6-9 show in elevation with parts broken away for clarity various fluidized bed nozzles which may be used in conjunction with the configuration of Figure 5;
Figure 10 is a vertical cross-sectional view of a second presently preferred embodi~ent of the present in~ention;
Figure 11 is a cross-sectional view in plan of the embodiment of Figure 10 taken along lines 11-11 of Figure 10;
Figure 12 is a cross-sectional view taken along lines 12-12 of Figure 11; and Figure 13 is an enlarged elevational view of the fuel in~ection system of the embodiment of Figure lOo DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
~ Reference is now made to the embodiment illustrated in : Figures 1-9 wherein like numerals are used to designate like parts throughout. Broadly~ the solid organic waste low pollu-tion incinerator, generally designated 10~ comprises apparatus for continually delivering fuel which may comprise pieces of solid ~as~e 12 to an incineration or pyrolysis site.
Thereafter, the pieces of solid waste 12 are caused to become somewhat homogeneously distributed within a fluidized bed ; 30, disposed near the bottom of an incineration vessel 26.
While any conveyance may be used to so deposit the sDlid waste ~O~Slg ~
pieces 12 within the fluidized bed 30, including the direct injection of the pieces into the bed, a box conveyor 14 is illustrated in Figure 1. Conveyor 14 comprises a conveyor belt 16 conventionally driven and displaced around either roller 17 whereby the solid waste pieces 12 fall into the vessel and are distributed by an impact cone 19 which is mounted on a column 21 and in turn supported by a cross member 23.
Mechanisms may be used in conjunction with the box conveyor 14 to meter the rate at which solid wast~e pieces are fed into the incinerator. As a consequence, the pieces of solid waste 12, which, by way of example, may comprise wood waste and like stoc~ refuge, are caused to be evenly distributed and embedded within the fluidized bed 30.
Depending upon the particular material and circum-stances, pieces of solid waste 12 may be pre-dried beore being fed into the incinerator, or water may be added thereto prior to or slmultaneously with displacement into the incinerator. In any event, said pieces are subject to high temperature combustion9 with or without carbonaceous residue~ depending upon operating temperature, oxygen available and mode of operation.
A vapor zone 34, immediately above the fluidized bed 30 comprises a site where volstile matter, released by the pieces of solid waste 12 during combustion occurring in the fluidized bed, are in turn combusted spontaneously or by separate ignition means. Since the process is con-tinuous, the heat of combustion within the fluidized bed and ~he heat of combustion in the vapor space complement each other so that operating temperatures are readily maintained, once established.
An air delivery system 32 drives air under pressure as indicated by arrows 40 from the source of pressurized ~o~
air 25 upward into the fluidized bed 30 adequate to establish and sustain the requisite combustion. Initially, high temperature air under pressure i~ used, being obtained from a conventional air heater 42. Once the fluidized bed 30 has reached the desired operating temperature or slightly below that temperature, the air heater 42 is switched off and a high capacity squirrel cage blower 25 or the like continues to deliver ambient air to the fluidized bed Blower 44 is driven by motor Ml.
Gaseous exhaust passes from the vessel 26 through an effluent conduit 50 either directly into the atmosphere where the parts per million of solid particles in the exhaust do not exceed maximum limits permitted for the operating location in question, or through auxiliary mechanisms where such solid particle content is adequately reduced.
If and to the extent desired, heat may be recovered from the vessel 26 using a conventional b~iler or the like.
Also, the temperatures within the vessel 26 may be controlled by selecting an amount of moisture to be introduced into the vessel during operation.
With greater specificity, the fluidized bed vessel 26 comprises a right circular cylinder of sheet metal which is preferably insulated by refractory material along the inside thereof. A horizontally disposed top 27, also preferably insulated in the s~me fashion, seals ~he vessel except for influent air, influent solid waste pieces and effluent exhaust.
~or greater detail in the manner ~n which the vessel 36 and auxiliary features may be fabricated and assembled, reference may be had to my Can~dian patent ~o. 990,145 issued J~ne 1, 1976.
lO~;Sl9 1 Openings 29, 31 and 33 acco~modate introduction of solid waste pieces, introduction of influent air, and expulsion of exhaust, respectively.
The air delivery system 32 discharges air under pressure received from blower 25 along conduit 35 through opening 37 into air feed chamber 39. The air under pressure from chamber 39 is forced through apertures 41 and 43 in grid plate 45 directly into the fluidized bed and through bed nozzles 47, respectively. Preferably, adequate struc-tural support for grid plate 45 is provided by conventionalstructural steel members (not shown). The grid plate 45, preferably of mild steel, is uniformly perforated by said apertures 41 and 43 in evenly arranged X and Y rows. The apertures are sized so as to readily permit influent air from the air delivery system 32 to pass through the plate 45 into the remainder of the fluldized bed 30, causing an even distribution of air. Cover caps 51 of the nozzles 47 are disposed essentially at the interface between the materials comprising the fluidized bed 30 and a tramp zone 53 whereby passage of the particulate matter of the fluidized bed through apertures 43 is prevented. In like fashion, plates 55 are preferably used to cover the apertures 41 for the same purpose as some of the tramp zone 53 will comprise particulate matter from the fluidized bed.
The fluidized bed 30 comprises a layer 59 of fine granular particulate matter, which preferably uniquely comprises eight to thirty mesh olivine sand, r~sts upon the perforated plate 45 and receives therein the previously mentioned solid waste pieces 12, causing incineration or pyrolysis thereof, depending upon selected operating temperatures and other variables. It is preferred that olivine lOf~Sl9'~
sand of eight to thirty mesh size ran8e be used to form par-ticulate layer 59.
Surprisingly, research and development has established that a bed material comprising olivine sand results in superior performance both in reducing the tendency to fuse and cake and in the rate of particle breakdown and elutriation of the bed material, when compared with bed materials heretofore used.
Olivine sand is a mineral of small particle size identified by the chemical compound (Mg,Fe) SiO4. More specifically, olivine sand is available from the Olivine Corporation of 1015 Hilton Avenue, Bellingham~ Washington 98225 and has either of the following compositions:
Mountain Quarry Reef Point Quarry Silica (SiO ) 40.08% 42.2Z
Iron (Fe O3~ 8.82 6.4 Alumina ~Al O3) 2.22 ---Calcium Oxi~e (CaO) .24 18.4 Magnesia (NgO) 48.39 31.2 Sodium (Na 0) 0.04 Potassium ~K2O) 0.05 .
Chromite 0.2 99.89 98.4 The size analysis of olivine sand is reported as follows:
Retained on Weight U.S. Screen Size Percent #16 34.1 #20 56.0 #30 9.2 #40 0.4 pan 0.3 The specific gravity of olivine is 3.22 to 4.39 and with a hardness rating of 6.5 ~o 7Ø It is a rhombic crystalline form and will vary in col~r from olive green to grayish green to a yellowish brown. The material in a particle size varying from a twelve mesh to thirty mesh material is preferred, (U.S. standard gauge screens). It has been found to h.ave a low coefficient of thermal expansion, and is highly fracture resistant to the mechanical and thermal conditions to which it is subjected in the fluidized bed combustion process.
The test results are set forth in the attached copy .
of a publication entitled ~TEST RESULTS OLIVINE SAND as a 10 BED MATERIAL for the FLUID FLAME BURNER", by T.H. Daniels, dated October 15, 1974. .
The entire bed, excluding tramp layer 5S, may be on the order of nine inches to eighteen inches deep.
In respect to the bed nozzles 47 ~Figure 5), it has, surprisingly, been found that suitable bed nozzles, each disposed upon a stand pipe 61 (defining the height of the inactive zone 53) causes non-combustible larger sized material to be continuously removed from the active fluidized bed 30 thereby maintaining good quality bed properties at all times.
It has been found that the apertures 43 in the grid plate 45 must permit enough air flow to allow the particulate matter . of the bed to move upwardly under the force of said air.
The apertures 41 are preferably of smaller size and serve fundamentally to purge a substantial part of the particulate matter of the fluidized bed from the tramp zone 53.
lO~Sl9~
It is to be sppreciated that any one of a number of different types of bed nozzles may be used. Some suitable ~ed nozzles are illustrated in Figures 509. Each is mounted upon the stand pipe 61 and comprises a horizontal top or cover 51. In Figure 5, the cover 51 is disc shaped, is mounted upon a base plate 63 using columns 65, which in combination define a plurality of radially disposed, hori-zontally directed air effluent port 67~ The stand pipe 61 is welded to the base plate 63 at site 69. Each stand pipe 61 is likewise welded at sites 71 to the top of the grid plate 45.
With reference to Figure 6, the cover plate 51 is downwardly configurated to create the horizontally extending .
lip 73, which is welded to the bottom plate 63 and inter-rupted at two locations 180 from esch other to create air discharge ports 75.
In reference to Figure 7, the square cover plate 51 is mounted directly to the top of the stand pipe 61 by four spacers 79 located at each corner and secured at weld sites 77~ with four radially disposed air discharge ports 79 between the four corner spacers 79. Air escaping from the ports 79t is channeled between the bottom surface of top coYer plate 51 and the top surface of a lower square plate 631, the latter having a central aperture through which the stand pipe 61 extends and being welded to the stand pipe at sites 81.
Figure 8 is a further bed nozzle embodi.ment wherein the stand pipe 61 is closed at its upper end by plug 83 which is welded or otherwise suitably secured in position.
An external cap 85 fits around the upper end of the stand lO~Sl9'~
pipe 61 and is likewise secured thereto by weldin~ or the like. The cap 85 has a plurality of outwardly and down-wardly extending bores 87, which are sized and shaped to match apertures 89 disposed in the upper end of the stand pipe 61. Thus, air emitted from the bed nozzle of Figure 8 will be directed radially at an acute angle to the hori-zontal from the bores 87.
The bed nozzle embodiment of Figure 9 illustrates the cover plate 51 being supported upon and welded to 8 plurality of posts 91, the lower end of each post being welded to the interior of the stand pipe 61. The stand pipe 61 is flaired at its upper end 93, causing air expelled therefrom to be displaced generally radially in a horizontal plane beneath the cover plate 51.
A novel vortex generator system is best illustrsted in Figures 2-4. The system provides a source 101 of air under pressure which may be a squirrel cage blower driven by motor N2. It is preferred that motor M2 be a variable speed motor which may be regulated by the operator to control the rate at which air is introduced into the incinerator vessel 26 by the vortex ~enerator system.
Air issuing from the source 101 passes through main conduit 103 issuing into the incinerator vessel 26 through a plurality of discharge sites. The ma~ority of the air from main conduit 103 is displaced into the vessel 26 through nozzle 105 ~7hich downwardly extends into the vessel tightly through opening 31 in the top 27 thereof. Air discharge from the nozzle 105 proceeds as indicated by arrows 107, coming in contact with the top surface of the fluidized bed 30 as a vertical column and being displaced essentially radially outward thereafter. Said influent air~ ~7hich may be preheated as desired~ is elevated in temperature once it reache~ the -10~519~
vicinity of the fluidized bed 30 causing the same to commence to elevate along an annulus disposed between the cylindrical verti~al wall of the vessel 26 and the column of influent air shown at arrows 107.
Air fro~ the main conduit pipe 103 is channeled, as best illustrated in Figures 1 and 2~ by auxiliary conduits 109, 111 and 113 to supply a plurality of vortex nozzles llS. The nozzles 115 may be of any suitable type, the configuration shown in Figure 4 being acceptable. Each nozzle is fitted through the vertical wall of the ~essel 26 at sites 117 at an acute angle in regard to the radius thereof such that air issuing from each nozzle 115, while not tangential initially becomes tangential immediately upon merging with the annulus of air being circulated between the interior surface of the vertical wall of the vessel 26 and the downwardLy directed column of nfluent air 107. This phenomenon is best illustrated in Figure
2. Preferably~ as illustrated in Figure 3, the nozzles 115 are directed at a very slight angle downward fro~
the horizontal to restrict the rate at which the elevating vortex permits air to be discharged through outlet conduit 50.
Thus~ air flow elevating from the fluidized bed is collected in an annular ring ad~acent the walls of the vessel with the vortex nozzles discharging air at high veloci~y which intersects the annular gas stream causing rapid clockwise or counterclockwise rotation of the annulus of air~ depending upon the direction in which the nozzles are directed, each nozzle being situated to complement the other nozzles in the rotation of the annular ring of air. There is interface mixing with the vertical column of influent air 107 and the conservation of momentum 10~;519~
prevails resulting in vortical flow. It has been found thst use of the vortex as h~rein described causes fine particulate matter from the fluidized bed to be centri-fuged and returned to the bed. Also, the high velocity rotation prevents vertical channeling of air directly to the output 50 resulting in a far greater residence time for unburnt combustible particles. As a result, such small particles which are not otherwise centrifuged back into the fluidized bed are preserved in the vapor space above the bed until they are consumed.
Nith additional reference to Figure 2, it is to be observed that stagnation columns 119, at any desired location and in any desired numbers may be used to create a stagnation zone interfering with the otherwise high rotational velocity of small co~bustible particles aiding in their being returned to the fluidized bed.
In operation, incineration or pyrolysis of solid organic ~aste, using the present invention, will depend upon the operating temperature selected and available oxygen. It has been determined that at bed temperature slightly ~reater than 700 Fahrenheit, the volatile species emanating from the solid waste being consumed in the fluidized bed, are volatized, leaving a carbonaceous resi-due resembling charcoal $n the bed. The reaction is slightly exothermic. The volatile species will burn smokelessly at about 1100 Fahrenheit or greater; the carbonaceous residue volatizes at 1000 Fahrenheit and burns completely at temperatures of 1200 Fahrenheit or 8reater. Thus, when total incineration is desired, the temperature in the vapor space 34 is maintained above 1100 Fahrenheit than ~hat of the bed at 1000 Fahrenheit or above, pro-ducing energy which can be recovered using boilers or the like~
lO~S1~
On the other hand, if it is desired to recover the carbonaceous material as a by-product, the bed is maintained at about 1000 Fahrenheit and, under these conditions, the volatile species will, as before, burn smokelessly in the vapor space 34. Also, if the operatlng temperature of the bed is between 700 Fahrenheit and 1100 Fahrenheit, an oxygen availability limited to less than five percent (5%) concentration of the carbonaceous residue, the volatile species will result and each may be utilized, thereafter~ as a raw material in organic synthesis or other processes.
It is to be appreciated that if spontaneous ignition of the volatile species in the vapor space 34 does not occur, an auxiliary burner may be used to facilitate this end result.
To be certain of bed and space temperatures~ it is preferred that temperature sensors of known design be appropriately placed within the interior of the vessel.
It has also been found that once the fluidized bed 30 has been preheated using heater 42 to a temperature on the order of 700 Fahrenheit, the volatile species issuing to the vapor space 34 are or can be $gnited, increasing the vapor space and the bed temperatures to beyond the 1200 Fahrenheit level. Smoke free combustion of the volatile species results and total consumption of the carbonaceous solid residues, when total incineration is sought. The direct combustion air heater 42 is normally gradually shut down once the bed tenperature reaches a level of ~00 Fahrenheit and is completely shut off by the time the 1200 Fahrenheit or higher operating tempera-tures are reached, thereby not using any of the available oxygen in the fluidizing air.
Reference is now made to the embodiment illustrated _16-10~519'~
in Figures 10-13 and genera}ly designated 150. Only those portions of the embodiment 150 which are materially the same as the corresponding portion of the already described embodi-ment 10 will not hereinafter be described, in order to avoid duplication.
The solid organic waste low pollution incinerator 150 comprises a unique fuel feed system 152 which operates on the principle of an air jet pump~ The fuel feed conveyor 16 turning at roller 17 dispatches by force of gravity solid waste particles 12 through an opening 154 in a fuel feed chute 156 comprising a side port of the bifurcated fuel influent mechanism 158. The bifurcated fuel influent mechanism 158 passes through the top 160 of the refractory lined vessel 162 at aperture 164. Air is fed from blower 101 through the main conduit pipe 103 as heretofore described, to a fuel in~ection air jet nozzle 166 (Figure 13). Air under pressure emitted through nozzle 166 in a downward direction increases the air velocity at the output of the nozzle. The increàsed velocity results in a decreased static pressure in the region where the fuel feed chute 156 inter-sects the inlet air tube 168 of the bifurcated fuel in~ection mechanism 158. The decreased static pressure, in effect, creates a partial vacuum at the inlet to the fuel chute 154, thus virtually "sucking" the fuel into the chute 156. The outlet tube 170 is direc~ed to the center of the active bed region within the vessel 162 and is at an acute angle in respect to the inlet air tube 168. The action of the high velocity air entering with the fuel tends to spread the fuel evenly over the surface of the bed within the vessel 162.
The fluidized bed 172 of the embodiment 150 is uniquely comprised of olivine sand.
l~iSl9 1 The embodiment 15Q also comprises a ~ew fluidizing air system 180 that allows continuous recirculation and purification of the bed material during normal burning operation in a fashion such that uncombustible "tramp"
material, carried into the burner with the fuel, is contin-uously removed and eliminated. Fluidizing air is generated at main fluidi~ing blower 182, the squirrel cage or the like of which is caused to be rotated by motor M3 through a con-ventional V belt drive or the like. The fluidizing air is displaced from the blower 182 into a n~in ~luidizing air manifold 184. As can be seen from Figure 11, the manifold 184 extends over approxin~ately 105 of the peri-phery ad~acent the vessel 162 and is progressively constricted in both directions so as to create an even distribution of air into a plurality of rectangular ducts 186. The fluid-izing air exiting from the manlfold 184 is displaced into the parallel arrangement of rectangular ducts 186 which extend entirely across the bottom of the active bed area and are spaced one from the next such that the fluidizing nozzle pattern previously described in con3unction with the en~bodiment 10 is achieved without the use of a grid plate.
The ducts 186 are properly shaped and sized to insure a uniform air flow to each duct and are of uniform width and spacing one to another so that the rate at which bed material and tramp material ~igrates between said ducts is a predetermined known magnitude. The parallel duct arrange-ment provides several advantages over the prior art including the grid plate technique, i.e. (a) the narrow duct widths allo~s free passage of the active bed material and tra~p material to the cone shaped extraction bin below, (b) a relatively hot bed n~aterial passing between the ducts 10f~519'~
is cooled by the air within the ducts to a temperature compatible with the preferred carbon steel extraction bins, ducts, manifold and screens and at the same ~ime the fluid~
izing air is preheated, and (c) the vibration of the ducts, caused by the flow of fluldizing air, insures the continuous, uniform passage of the entire contents of the bed to the cone shaped extraction bin and screen conveyors below.
The length of the ducts varies from duct to duct because of the circular configuration of the illustrated refractory vessel 192. The free end of each duct is capped and preferably supported upon an expansion mechanism to accommo-date thermal expansion and contraction lengthwise while securing against lateral displacement. With the indicated arrangement, essentially the same magnitude of air is discharged from each nozzle 47. The influent to manifold 184 may be heated ~f desired by an auxiliary burner 188 ~Figure 11).
The granular bed material and tramp material passing adjacent the ducts fills the space created by and is supported by a cone shaped bin 190, having a ma~or diameter equal to the diameter of the active bed of the vessel 162 and a minor diameter which terminates in a vertical pipe or spout 192. The cone may be either a static cone or a dynamic vibrating cone or a two section cone having both a static and a dy~amic section. The spout discharges vertically onto a vibrating screen conveyor 194, which is driven by motor M4 so as to oscillate. m e screen conveyor 194 separates reusable bed material from tramp material with the ~ramp material proceeding up the conveyor 194, off the elevated end 196 and discarded. The reusable bed material passes through the mesh of the c~nveyor 194 onto a lower conveyor 198 and is discharged from the elevated end 200 ~o~
~ r lrl~o .I b~tl ll~at~ t)~ bll-l 20~ into ~
matcrlal rctuIn condult 204 alon~ which thc rctllrn bed matcrl~lly 1~ ~ls~lnce~ nnd ultlmatcly out erfluent end 206 thercor onto the fluldi7cd bed 172 wlthln the vesse~ 162 undcr rorce of blowcr 208 drlvcn by motor M5. Thus, tralllp materlal is rcmoved and the bod material is contlnuously recirculatcd ror reusc. The bln 200 also providcs a convenient polnt for thc addltlon Or new "makeup" bed materlal which ls required from time to tlme durlng normal operation Or the - 10 embodiment 150, due to partlcle elutriation and attritlon caused by particle fracture and abrasive wear. In this way, the bed inventory is maintalned at the optlmum level for proper fluidization.
The inventlon may be embodied in othcr speciric forms without departing from the spirit or essential characteristics thereof. The present embodiments are thererore to be considered in all respects as illustrative and not restrictive, the scope of the invention being lndicated by the appended claims rather than by the fore-going description, and all changes which come withinthe meaning and range Or equivalency Or the claims are therefore intended to be èmbraced therein.
What is claimed and desired to be secured by ;..
Letters Pa~ent is:
, . .
.
.' ~
~ -20-
the horizontal to restrict the rate at which the elevating vortex permits air to be discharged through outlet conduit 50.
Thus~ air flow elevating from the fluidized bed is collected in an annular ring ad~acent the walls of the vessel with the vortex nozzles discharging air at high veloci~y which intersects the annular gas stream causing rapid clockwise or counterclockwise rotation of the annulus of air~ depending upon the direction in which the nozzles are directed, each nozzle being situated to complement the other nozzles in the rotation of the annular ring of air. There is interface mixing with the vertical column of influent air 107 and the conservation of momentum 10~;519~
prevails resulting in vortical flow. It has been found thst use of the vortex as h~rein described causes fine particulate matter from the fluidized bed to be centri-fuged and returned to the bed. Also, the high velocity rotation prevents vertical channeling of air directly to the output 50 resulting in a far greater residence time for unburnt combustible particles. As a result, such small particles which are not otherwise centrifuged back into the fluidized bed are preserved in the vapor space above the bed until they are consumed.
Nith additional reference to Figure 2, it is to be observed that stagnation columns 119, at any desired location and in any desired numbers may be used to create a stagnation zone interfering with the otherwise high rotational velocity of small co~bustible particles aiding in their being returned to the fluidized bed.
In operation, incineration or pyrolysis of solid organic ~aste, using the present invention, will depend upon the operating temperature selected and available oxygen. It has been determined that at bed temperature slightly ~reater than 700 Fahrenheit, the volatile species emanating from the solid waste being consumed in the fluidized bed, are volatized, leaving a carbonaceous resi-due resembling charcoal $n the bed. The reaction is slightly exothermic. The volatile species will burn smokelessly at about 1100 Fahrenheit or greater; the carbonaceous residue volatizes at 1000 Fahrenheit and burns completely at temperatures of 1200 Fahrenheit or 8reater. Thus, when total incineration is desired, the temperature in the vapor space 34 is maintained above 1100 Fahrenheit than ~hat of the bed at 1000 Fahrenheit or above, pro-ducing energy which can be recovered using boilers or the like~
lO~S1~
On the other hand, if it is desired to recover the carbonaceous material as a by-product, the bed is maintained at about 1000 Fahrenheit and, under these conditions, the volatile species will, as before, burn smokelessly in the vapor space 34. Also, if the operatlng temperature of the bed is between 700 Fahrenheit and 1100 Fahrenheit, an oxygen availability limited to less than five percent (5%) concentration of the carbonaceous residue, the volatile species will result and each may be utilized, thereafter~ as a raw material in organic synthesis or other processes.
It is to be appreciated that if spontaneous ignition of the volatile species in the vapor space 34 does not occur, an auxiliary burner may be used to facilitate this end result.
To be certain of bed and space temperatures~ it is preferred that temperature sensors of known design be appropriately placed within the interior of the vessel.
It has also been found that once the fluidized bed 30 has been preheated using heater 42 to a temperature on the order of 700 Fahrenheit, the volatile species issuing to the vapor space 34 are or can be $gnited, increasing the vapor space and the bed temperatures to beyond the 1200 Fahrenheit level. Smoke free combustion of the volatile species results and total consumption of the carbonaceous solid residues, when total incineration is sought. The direct combustion air heater 42 is normally gradually shut down once the bed tenperature reaches a level of ~00 Fahrenheit and is completely shut off by the time the 1200 Fahrenheit or higher operating tempera-tures are reached, thereby not using any of the available oxygen in the fluidizing air.
Reference is now made to the embodiment illustrated _16-10~519'~
in Figures 10-13 and genera}ly designated 150. Only those portions of the embodiment 150 which are materially the same as the corresponding portion of the already described embodi-ment 10 will not hereinafter be described, in order to avoid duplication.
The solid organic waste low pollution incinerator 150 comprises a unique fuel feed system 152 which operates on the principle of an air jet pump~ The fuel feed conveyor 16 turning at roller 17 dispatches by force of gravity solid waste particles 12 through an opening 154 in a fuel feed chute 156 comprising a side port of the bifurcated fuel influent mechanism 158. The bifurcated fuel influent mechanism 158 passes through the top 160 of the refractory lined vessel 162 at aperture 164. Air is fed from blower 101 through the main conduit pipe 103 as heretofore described, to a fuel in~ection air jet nozzle 166 (Figure 13). Air under pressure emitted through nozzle 166 in a downward direction increases the air velocity at the output of the nozzle. The increàsed velocity results in a decreased static pressure in the region where the fuel feed chute 156 inter-sects the inlet air tube 168 of the bifurcated fuel in~ection mechanism 158. The decreased static pressure, in effect, creates a partial vacuum at the inlet to the fuel chute 154, thus virtually "sucking" the fuel into the chute 156. The outlet tube 170 is direc~ed to the center of the active bed region within the vessel 162 and is at an acute angle in respect to the inlet air tube 168. The action of the high velocity air entering with the fuel tends to spread the fuel evenly over the surface of the bed within the vessel 162.
The fluidized bed 172 of the embodiment 150 is uniquely comprised of olivine sand.
l~iSl9 1 The embodiment 15Q also comprises a ~ew fluidizing air system 180 that allows continuous recirculation and purification of the bed material during normal burning operation in a fashion such that uncombustible "tramp"
material, carried into the burner with the fuel, is contin-uously removed and eliminated. Fluidizing air is generated at main fluidi~ing blower 182, the squirrel cage or the like of which is caused to be rotated by motor M3 through a con-ventional V belt drive or the like. The fluidizing air is displaced from the blower 182 into a n~in ~luidizing air manifold 184. As can be seen from Figure 11, the manifold 184 extends over approxin~ately 105 of the peri-phery ad~acent the vessel 162 and is progressively constricted in both directions so as to create an even distribution of air into a plurality of rectangular ducts 186. The fluid-izing air exiting from the manlfold 184 is displaced into the parallel arrangement of rectangular ducts 186 which extend entirely across the bottom of the active bed area and are spaced one from the next such that the fluidizing nozzle pattern previously described in con3unction with the en~bodiment 10 is achieved without the use of a grid plate.
The ducts 186 are properly shaped and sized to insure a uniform air flow to each duct and are of uniform width and spacing one to another so that the rate at which bed material and tramp material ~igrates between said ducts is a predetermined known magnitude. The parallel duct arrange-ment provides several advantages over the prior art including the grid plate technique, i.e. (a) the narrow duct widths allo~s free passage of the active bed material and tra~p material to the cone shaped extraction bin below, (b) a relatively hot bed n~aterial passing between the ducts 10f~519'~
is cooled by the air within the ducts to a temperature compatible with the preferred carbon steel extraction bins, ducts, manifold and screens and at the same ~ime the fluid~
izing air is preheated, and (c) the vibration of the ducts, caused by the flow of fluldizing air, insures the continuous, uniform passage of the entire contents of the bed to the cone shaped extraction bin and screen conveyors below.
The length of the ducts varies from duct to duct because of the circular configuration of the illustrated refractory vessel 192. The free end of each duct is capped and preferably supported upon an expansion mechanism to accommo-date thermal expansion and contraction lengthwise while securing against lateral displacement. With the indicated arrangement, essentially the same magnitude of air is discharged from each nozzle 47. The influent to manifold 184 may be heated ~f desired by an auxiliary burner 188 ~Figure 11).
The granular bed material and tramp material passing adjacent the ducts fills the space created by and is supported by a cone shaped bin 190, having a ma~or diameter equal to the diameter of the active bed of the vessel 162 and a minor diameter which terminates in a vertical pipe or spout 192. The cone may be either a static cone or a dynamic vibrating cone or a two section cone having both a static and a dy~amic section. The spout discharges vertically onto a vibrating screen conveyor 194, which is driven by motor M4 so as to oscillate. m e screen conveyor 194 separates reusable bed material from tramp material with the ~ramp material proceeding up the conveyor 194, off the elevated end 196 and discarded. The reusable bed material passes through the mesh of the c~nveyor 194 onto a lower conveyor 198 and is discharged from the elevated end 200 ~o~
~ r lrl~o .I b~tl ll~at~ t)~ bll-l 20~ into ~
matcrlal rctuIn condult 204 alon~ which thc rctllrn bed matcrl~lly 1~ ~ls~lnce~ nnd ultlmatcly out erfluent end 206 thercor onto the fluldi7cd bed 172 wlthln the vesse~ 162 undcr rorce of blowcr 208 drlvcn by motor M5. Thus, tralllp materlal is rcmoved and the bod material is contlnuously recirculatcd ror reusc. The bln 200 also providcs a convenient polnt for thc addltlon Or new "makeup" bed materlal which ls required from time to tlme durlng normal operation Or the - 10 embodiment 150, due to partlcle elutriation and attritlon caused by particle fracture and abrasive wear. In this way, the bed inventory is maintalned at the optlmum level for proper fluidization.
The inventlon may be embodied in othcr speciric forms without departing from the spirit or essential characteristics thereof. The present embodiments are thererore to be considered in all respects as illustrative and not restrictive, the scope of the invention being lndicated by the appended claims rather than by the fore-going description, and all changes which come withinthe meaning and range Or equivalency Or the claims are therefore intended to be èmbraced therein.
What is claimed and desired to be secured by ;..
Letters Pa~ent is:
, . .
.
.' ~
~ -20-
Claims (3)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An incineration system comprising:
a generally cylindrical incineration chamber;
a fluidized bed located within the chamber with a vapor space defined in the chamber above the fluidized bed;
means causing combustible waste to be introduced into the incineration chamber and dispersed within the fluidized bed;
effluent opening means above the vapor space communicating exhaust from the interior of the chamber;
influent air means communicating air into the interior of the chamber and being disposed centrally above the fluidized bed directing said air centrally downward against the fluidized bed and causing air to elevate within the chamber as an annulus adjacent the wall of the chamber;
auxiliary influent air means communicating air into the interior of the chamber adjacent the wall of the chamber within the vapor space with at least the major component of air displaced therefrom being tangential to the wall when introduced into the chamber;
whereby a gradually elevating annular vortex of air is created whereby fine particles are centrifuged from the vapor space to the fluidized bed and vapor space residence time for any residual particles is increased accommodating complete combustion.
a generally cylindrical incineration chamber;
a fluidized bed located within the chamber with a vapor space defined in the chamber above the fluidized bed;
means causing combustible waste to be introduced into the incineration chamber and dispersed within the fluidized bed;
effluent opening means above the vapor space communicating exhaust from the interior of the chamber;
influent air means communicating air into the interior of the chamber and being disposed centrally above the fluidized bed directing said air centrally downward against the fluidized bed and causing air to elevate within the chamber as an annulus adjacent the wall of the chamber;
auxiliary influent air means communicating air into the interior of the chamber adjacent the wall of the chamber within the vapor space with at least the major component of air displaced therefrom being tangential to the wall when introduced into the chamber;
whereby a gradually elevating annular vortex of air is created whereby fine particles are centrifuged from the vapor space to the fluidized bed and vapor space residence time for any residual particles is increased accommodating complete combustion.
2, The incineration system according to claim 1 wherein the interior of said generally cylindrical incineration chamber comprises at least one vertical stagnation column adjacent the interior surface of the wall of the chamber which interferes with the periphery of said elevating annular vortex and aids in returning fine particles from the vapor space to the fluidized bed.
3. A method of low pollution eliminating of solid particles vaporized during incineration, the steps of:
elevating the temperature of a confined fluidized bed to an order of magnitude capable of supporting combustion;
continuously causing pieces of solid waste to become embedded within the confined fluidized bed;
impinging influent air centrally downward against the fluidized bed within the confinement;
combusting the solid waste within the fluidized waste and volatizing the volatile matter contained within the solid waste into the vapor space between the top of the fluidized bed and the top of the confinement;
after-burning the volatile matter in the vapor space extending substantially above the fluidized bed;
causing an annulus of air to be vortically circulated around the impinging influent air throughout substantially the entirety of the vapor space within the confinement to increase residence time, prevent channeling and centrifuging airborne solid particles causing at least some of said particles to return to the bed by force of gravity.
elevating the temperature of a confined fluidized bed to an order of magnitude capable of supporting combustion;
continuously causing pieces of solid waste to become embedded within the confined fluidized bed;
impinging influent air centrally downward against the fluidized bed within the confinement;
combusting the solid waste within the fluidized waste and volatizing the volatile matter contained within the solid waste into the vapor space between the top of the fluidized bed and the top of the confinement;
after-burning the volatile matter in the vapor space extending substantially above the fluidized bed;
causing an annulus of air to be vortically circulated around the impinging influent air throughout substantially the entirety of the vapor space within the confinement to increase residence time, prevent channeling and centrifuging airborne solid particles causing at least some of said particles to return to the bed by force of gravity.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA312,919A CA1065194A (en) | 1975-06-30 | 1978-10-10 | Low pollution incineration of solid waste |
| CA335,316A CA1082045A (en) | 1975-06-30 | 1979-09-10 | Low pollution incineration of solid waste |
| CA335,317A CA1082046A (en) | 1975-06-30 | 1979-09-10 | Low pollution incineration of solid waste |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US05/591,556 US4060041A (en) | 1975-06-30 | 1975-06-30 | Low pollution incineration of solid waste |
| CA76244266A CA1048861A (en) | 1975-06-30 | 1976-01-27 | Low pollution incineration of solid waste |
| CA312,919A CA1065194A (en) | 1975-06-30 | 1978-10-10 | Low pollution incineration of solid waste |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1065194A true CA1065194A (en) | 1979-10-30 |
Family
ID=27164298
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA312,919A Expired CA1065194A (en) | 1975-06-30 | 1978-10-10 | Low pollution incineration of solid waste |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1065194A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106016270A (en) * | 2016-06-06 | 2016-10-12 | 无锡多灵环保工程设备有限公司 | Energy-saving efficient garbage incinerator |
-
1978
- 1978-10-10 CA CA312,919A patent/CA1065194A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106016270A (en) * | 2016-06-06 | 2016-10-12 | 无锡多灵环保工程设备有限公司 | Energy-saving efficient garbage incinerator |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4060041A (en) | Low pollution incineration of solid waste | |
| US6202573B1 (en) | Apparatus and process for carbon removal from fly ash | |
| US3834326A (en) | Low pollution incineration of solid waste | |
| CA1065193A (en) | Low pollution incineration of solid waste | |
| WO1988002284A1 (en) | Treatment of waste and a rotary kiln therefor | |
| JPS6217123B2 (en) | ||
| SE447672B (en) | KIT AND FLUID BED COMBUSTION | |
| US3482533A (en) | Incinerators | |
| SE464429B (en) | PROCEDURE AND DEVICE FOR DRYING WATER WOODEN WASTE USING FLUIDIZED BEDDING | |
| US4510021A (en) | Fluidized bed charcoal particle production system | |
| JP2764382B2 (en) | Circulating fluidized bed reactor for low-grade fuel | |
| US5060584A (en) | Fluidized bed combustion | |
| US5101742A (en) | Fluidized bed combustion | |
| US3745940A (en) | Fluidised bed apparatus and method | |
| JPS5810643B2 (en) | Shoukiya Chrono Kairyo | |
| CA1065194A (en) | Low pollution incineration of solid waste | |
| CA1082045A (en) | Low pollution incineration of solid waste | |
| CA1082046A (en) | Low pollution incineration of solid waste | |
| US2577000A (en) | Apparatus for incinerating waste material | |
| AU664608B2 (en) | Incineration apparatus | |
| AU658297B2 (en) | Method for treating soil contaminated with hydrocarbons | |
| EP3471857A1 (en) | Filter apparatus for treatment of fluids and a gasifier for use in a gasification process | |
| JP2006213795A (en) | Carbonization apparatus | |
| JP3659834B2 (en) | Method and apparatus for removing dioxins in incineration ash and fly ash | |
| RU2069907C1 (en) | Device for recovery of combustible toxic wastes |