Note: Descriptions are shown in the official language in which they were submitted.
~2~ 47
INCINERATION SYSTEM
BACKGROUND ~F T~E IN~ENTION
This invention relates in general to in-
cineration systems and deals more particularly with an
improved system of the type which includes a rotary
primary oxidation chamber and a secondary oxidation
chamber or afterburner which receives gaseous products of
combustion from the primary chamber.
Heretofore, incineration systems of the afore-
described general type have been provided which are cap-
able of burning waste materials including solids, semi-
solids, liquids and sludges individually or in combina-
tion. However, because of the variable characteristics
of the material processed, as, for example, the BTU value
per pound, density, moisture content, percentage of inert
material and resistance to feeding, such incineration
systems have proven most difficult to control. Wide
fluctuations in the operational conditions within a
system have an adverse effect upon the overall efficiency
of the system. Substantial additional heat input from
one or more external auxiliary heat sources is often re-
quired to maintain uniform operational conditions within
such an incineration system to achieve efficient waste
incineration while maintaining system emissions within
acceptable environmental control standards. Further,
maintenance of sufficient retention time in both the pri-
mary oxidation chamber and the secondary oxidation
chamber of such a system is a major factor in achievement
of a high degree of system efficiency.
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It is the general aim of the present invention
to provide an improved incineration system of the afore-
described general type for disposing of waste materials
including solids, semi-solids, liquids, and sludges,
which may be toxic or hazardous. A further aim of the
invention is to provide an incineration system which may
be controlled to maintain substantially uniform opera-
tional characteristics and high efficiency, despite the
widely varying characteristics of the waste material pro-
cessed, and which attains efficient energy recovery whilemeeting or exceeding accepted environmental control
standards.
SUMMAR~ OF THE INVENTION
In accordance with the present invention an in-
cineration system comprises a rotary drum defining a gen-
erally horizontally disposed primary oxidation chamber,
and a vertically disposed secondary oxidation chamber,
which has an inlet opening in its lower portion and an
outlet opening in its upper portion. A discharge opening
in one end of the drum communicates with the inlet open-
ing in the secondary chamber. Baffle means disposed
within the secondary chamber include a first baffle wall,
inclined upwardly and in the direction of the discharge
opening for blocking flow of gases and other products of
combustion from the lower portion of the primary oxida-
tion chamber into the secondary oxidation chamber. The
baffle means further include a second baffle wall inclin-
ed downwardly from a position above the discharge opening
and in a direction away from the discharge opening. The
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12~(~6~7
baffle walls cooperate with walls of the secondary oxida-
tion chamber to define a tortuous flow path for gases of
combustion which flow from an upper portion of the pri-
mary oxidation chamber into and through the secondary
oxidation chamber to the outlet opening.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a perspective view of an incineration
system embodying the present invention.
Fig~ 2 is a somewhat schematic longitudinal sec-
tional view through the incinerator shown in Fig. 1.
Fig. 3 is a fragmentary sectional view taken
along the line 3-3 of Fig~ 2.
Fig. 4 is a somewhat enlarged fragmentary sec-
tional view taken along the line 4-4 of Fig. 2.
Fig. 5 is similar to Fig. 2 and shows a somewhat
enlarged fragmentary sectional view of the incinerator as
it appears in Fig. 2.
Fig. 6 is a fragmentary sectional view taken
along the line 6-6 of Fig. 5.
Fig. 7 is a somewhat enlarged fragmentary plan
view of a typical baffle wall element.
Fig. 8 is a sectional view taken along the line
8-8 of Fig. 7.
Fig. 9 is similar to Fig. 7 but shows another
baffle wall element.
Fig. 10 is a sectional view taken along the line
10-10 of Fig. 9.
Fig. ]l is a fragmentary sectional view similar
to Fig. 2, but shows another incinerator.
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DETAILED DESCRIPTION OF PREFERRED EMBODIMENT
Turning now to the drawings, and referring
particularly to Fig. 1, an incineration system embodying
the present invention is indicated generally by the re-
ference numeral 10. The illustrated system 10 generally
comprises an incinerator designated generally by the
numeral 12, which includes a rotary primary oxidation
chamber 14 and a secondary stationary oxidation chamber
16 which receives gaseous products of combustion from the
primary oxidation chamber. An ignition burner 18 in-
itiates the incineration process and, depending on the
nature of the waste material being burned, may supply
additional heat to maintain proper temperatures within
the primary oxidation chamber 14. An ash receiver 20,
located generally below the secondary oxidation chamber
16, receives ash and other unburned material from both
the primary and secondary oxidation chambers.
A suitable feeding apparatus is provided for
handling the waste material to be processed. The il-
lustrated apparatus 10 is particularly adapted to burnsolid and semi-solid waste and/or sludge and has an
auger/shredder feeding apparatus, indicated generally at
22, particularly adapted to shred and compact bulky solid
waste as it is fed into the incinerator 12. One or more
additional burners, such as the burner 24, may be pro-
vided to assure maintenance of predetermined temperatures
within the secondary oxidation chamber 16, however, where
the waste material to be burned has a low to medium BTU
value per pound (1500 BTU dry) the oxidizing process will
0 be self-sustaining. In some circumstances material hav-
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lZ1~647
ing an even lower BTU value per pound and relatively high
moisture contents can be accommodated and maintained in
self-sustaining mode.
In the illustrated system lO, hot gases from the
secondary oxidation chamber pass into a heat exchanger,
such as the illustrated waste heat boiler 26, through a
refractory lined stack 28 which has a built-in bypass to
allow passage of hot gases directly up the stack under
emergency conditions and while shutting down the feeding
apparatus. A strategically located exhaust fan 29 in-
duces a draft to create negative pressure within the
system while returning to the atmosphere environmentally
safe gases received from a baghouse 30 and a packed tower
scrubber 32, which comprise part of the illustrated
system 10. However, it should be understood that an in-
cineration system constructed in accordance with the pre-
sent invention may not require a baghouse, scrubber or
other external particulate removal device. A control
system indicated generally at 33, which includes a con-
troller 34 and associated instrumentation, is provided
for controlling the incineration system 10, as will be
hereinafter more fully discussed. Safety interlocks
monitor high and low temperatures, waste feed rates, boi-
ler water level and pressure, burner operation and pol-
lution control apparatus to allow continuous operation
with minimal supervision.
Considering now the incinerator 12 in further
detail, and referring particularly to Figs. 2-4, the pri-
mary oxidation chamber 14 is defined by a cylindrical
drum, indicated generally at 36, which is closed at its
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~Zl(~6~7
front end and has a discharge opening 43 at its rear end,
as best shown in Fig~ 2. The drum 36 has an outer shell
38 formed from sheet metal and lined with refractory
material. The illustrated refractory material include~
arched firebricks 40, 40 which cooperate with the outer
shell to define a plurality of individual passageways 42,
42 between the refractory lining and the outer shell, as
best shown in Figs. 4 and 5. Each passageway 42 communi-
cates with an associated opening 39 in the outer shell
38 near the rear end of the shell and with another as-
sociated opening 45 in front end of the outer shell 38,
as best shown in Fig. 5. The passageways 42, 42 extend
substantially throughout the length of the drum in gener-
ally parallel relation to the axis of rotation of the
drum, the latter axis heing indicated by the numeral 41
in Fig. 2.
The drum 38 is supported for axial rotation by a
plurality of rollers 44, 44 journalled on a supporting
frame structure and engaged with annular bands which sur-
round the outer periphery of the drum shell 38, as shownin Fig~ 1. The drum 36 is preferably supported with its
axis of rotation 41 downwardly inclined from the horizon-
tal and in the direction of its open or discharge end.
The rollers 44, 44 at opposite sides of the drum are ad-
justable generally toward and away from each other to
permit variation of the angle of inclination of the drum
axis 410 A reversible, variable speed drive motor 46,
indicated diagrammatically in Fig. 2, is provided for ro-
tating the drum 36 about its axis of rotation, as will be
hereinafter further discussed. The primary oxidizing
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lZl(~64~
chamber or drum 36 is preferably enclosed within a pri-
mary air shroud assembly 47, which includes a front wall
49 and which has a feeder door assembly 51. An annular
seal 35 is provided between the front end of the drum 38
and the shroud 47, as best shown in Fig. 5. Air inlet
holes, such as the one indicated at 37 in Fig. 5, are or
may be provided in the shroud 47 near the discharge end
of the drum 36 to admit makeup air into the primary oxi-
dation chamber 14, however, the illustrated incinerator
12 has an air inlet conduit 53 in its shroud near its
front end. A blower 29 is or may be provided to deliver
air to the conduit 53, as shown in Fig. 5. An adjustable
damper or butterfly valve 33 in the conduit 53 may be
manually or automatically adjusted to control air flow
into the primary combustion chamber 14 through the shroud
47. Air flows into the space between the shroud and the
drum, through the openings 39, 39 in the drum shell 38,
through the passageways 42, 42 and out through the open-
ings 45, 45 at the front end of the drum shell cooling
the shroud and drum. The resulting preheated air enters
the drum through an opening in its front or infeed end,
being drawn into the unit by negative pressure induced by
the fan 29.
The secondary oxidation chamber 16 is generally
vertically disposed and has a substantially rectangular
cross section, as best shown in Fig. 4. It has an outer
metal shell, and a liner, preferably formed from retrac-
tory material, and includes a rear wall 48, a front wall
50, side walls 52 and 54, and a top wall 56. A circular
0 inlet opening 58 is formed in the front wall 50 and re-
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121()647
ceives an associated portion of the rear or discharge end
of the drum 36 therein so that the discharge opening 43
communicates with the secondary oxidation chamber 16. An
outlet opening 60 in the side wall 54 at the upper por-
tion of the secondary oxidizing chamber 16 is connected
to the stack 28 by an associated outlet duct 61.
In accordance with the present invention, the
secondary oxidation chamber 16 includes a plurality of
baffle walls, shown in Fig. 2, which extend transversely
across the secondary chamber between the side walls 52
and 54. The baffle walls cooperate with the walls of the
chamber to define a tortuous flow path for gases of com-
bustion which flow from the primary oxidation chamber 14
into and through the secondary oxidation chamber 16 to
and through the outlet opening 60. More specifically,
the secondary oxidizing chamber 16 has a first baffle
wall 62 which is inclined upwardly and forwardly from a
position below the center of the discharge opening 43 and
in the direction thereof. The baffle wall 62 terminates
at a position above the center of the discharge opening
and serves to block flow of gases, ash, inert materials,
particulate and other products of combustion from a lower
portion of the primary oxidation chamber 14 into the gas
stream entering the secondary oxidation chamber 16. Pre-
ferably, and as shown, the first baffle wall 62 is up-
wardly inclined to the horizontal at an angle in the
range of 65 to 70 degrees, the latter angle being in-
dicated by the reference numeral 64 in Fig. 2. A second
baffle wall 66 extends from the front wall 50 at a posi-
tion above the discharge opening 43 and is inclined down-
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lZ~)647
wardly and in a direction away from the discharge opening
43. Preferabl~, and as shown, the baffle wall 66 is in-
clined at an angle of approximately 45 degrees to the
vertical, the latter angle being indicated by the refer-
ence numeral 68 in Fig. 2. It should be noted ihat the
first and second baffle walls 62 and 66 diverge in a
direction away from the discharge opening 43 to define a
first venturi region 67, for a purpose which will be
hereinafter further discussed.
The illustrated incinerator 10 further includes
a third baffle wall 70 inclined downwardly from the rear
wall 48 and toward the second baffle wall 66. The third
baffle wall 70 terminates at a generally transverely ex-
tending front edge spaced from the second baffle wall 66.
Preferably, and as shown, the third baffle wall 70 is
generally normal to the second baffle wall 66. A fourth
baffle wall 72, defined by a lower portion of the rear
wall 48, is inclined downwardly and in the direction of
the discharge opening 43. The second baffle wall 66 is
preferably generally normal to the fourth baffle wall 72
and terminates at a rear edge spaced from the fourth baf-
fle wall. The baffle wall venturis are sized relative to
gas flow to create a distribution of the gases over the
full width of the secondary oxidation chamber, thus dis-
couraging streaming of gases along paths of least resist-
ance. This arrangement encourages full utilization of
the secondary combustion chamber, increases residence
time for total combustion capability and results in more
~fficient combustion per cubic foot with a small volume
chamber.
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~2~0~47
Preferably, at least one of the baffle walls 62,
68 and 70 comprises an assembly of unitary axially
elongated ceramic elements loosely associated in adjacent
axially parallel sideby-side relation and extending
transversely between the side walls of the secondary
oxidation chamber. In the illustrated incinerator 12,
each of the baffle walls is made from a plurality of axi-
ally elongated ceramic tubes 73, 73, packed with high
temperature insulating material 71. The ends of the
tubes 73, 73 are supported by courses of refractory
material which project inwardly from the side walls 52
and 54 to form supporting shelves for the elongated
elements. In Fig. 4 the supporting shelves are indicated
at 75, 75. Thus, a baffle wall is readily formed by
resting the elements 73, 73 on the shelves 75, 75 and ad-
jacent each other. Alternatively, one or more of the
baffle walls may be formed from a plurality of axially
elongated solid ceramic rods 73a, 73a. A typical rod 73a
is shown in Figs. 7 and 8.
A slotted ceramic air header 74 extends
transversely of the secondary oxidation chamber 16 along
the rear edge of the second baffle wall 66, as will be
hereinafter further discussed. A plurality of wide angle
view sight glasses are or may be provided in the walls of
the secondary oxidation chamber 16 to permit observation
of conditions within the chamber. A safety explosion cap
may also be provided for venting gas from the chamber 16
in the event of an excessive pressure build-up with the
chamber, however, for clarity of illustration the sight
glasses and safety explosion cap are not shown.
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lZlQ647
The illustrated feeding apparatus 22 comprises
an auger/shredder which includes an auger 74 supported
for rotation within a compaction tube 76 and a loading
hopper 78 for supplying waste material to the auger. The
auger 74 is driven by a variable speed drive motor 80,
diagramatically illustrated in Fig. 2.
The ash receiver 20 is disposed generally below
the secondary combustion chamber 16 to receive ash and
other unburned material from both the primary and the
secondary combustion chambers. The ash receiver has in-
ner and outer walls and baffles (not shown) disposed
between the latter walls which cooperate with thP walls
to define a tortuous ash cooling passageway 82 there-
between, as shown somewhat schematically in Fig. 2. A
conduit 84 communicates with the cooling passageway 82
and with the secondary combustion chamber 16 for a pur-
pose which will be hereinafter further discussed. An air
impeller or blower (not shown) may be provided for moving
air within the cooling passageway 82 and the conduit 84.
Unburned residue from the ash receiver is deposited con-
tinuously on a sha~er hearth or other movement device
such as the illustrated conveyor belt 86 which may be of
a solid plate-type and which is shrouded against un-
controlled air introduction. The conveyor belt 86
carries this ash and inert unburned material away from
the base of the secondary oxidation chamber and deposits
it in a waiting container (not shown) located below a
pair of hopper doors 85.
Preparatory to operating the incineration system
12 the burners 18 and 24 are operated to bring the pri-
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i23~647
mary and secondary oxidation chambers up to predetermined
temperatures. Temperature sensing devices 88 and 90
which comprise part of the control system 33 are disposed
within the first and second oxidation chambers 14 and 16
for monitoring temperatures and/or rates of temperature
change therein. Solid or semi-solid waste materials
and/or sludges are loaded into the hopper 78. Another
sensing device 92 which forms part of the control system
33 and which may, for example, comprise a photoelectric
cell, is arranged to detect the presence of a predeter-
mined quantity of waste material in the hopper 78. When
the temperature sensing devices 88 and 90 in the first
and second oxidation chambers indicate that the tempera-
tures therein have reached predetermined levels and the
sensing device 92 associated with the hopper 78 indicates
that the waste material therein equals or exceeds a pre-
determined quantity, the auger drive motor 80 is auto-
matically activated by the controller 34 initiating the
feeding cycle.
The incinerator 12 operates most efficiently
when the wastes being fe~ into it are uniformly sized and
of uniform density. Solid waste materials as found in
industrial and municipal waste stream are seldom uni-
formly sized and in fact vary widely in their density,
size, and BTU content characteristics, for example, low
heating value wet materials such as garbage together with
relatively dense materials like paper catalog and com-
puter run offs are often mixed with high heat value
plastics, wooden construction materials, light and com-
pressible waste basket trash and a variety of noncombus-
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iZ~LU647
tibles. The auger/shredder 22 solves these problems.
The rotating auger 74 captures waste material
supplied to it by the hopper 78 and forces the material
into the compaction tube 76, while breaking, shredding
and crushing it, thereby reducing it to somewhat uniform
size and density. A fairly dense sausage-like plug of
waste material results, which is fed into the primary
oxidation chamber 14 while reducing if not substantially
wholly eliminating entry of air through the compaction
tube 76. Thus, mechanical doors or other sealing devices
are not required at the entry end of the incinerator.
The sensing devices hereinbefore described which comprise
the control system 33 automatically shutdown the
auger/shredder 22 if material within the hopper falls
below a predetermined level or if the temperature within
either the primary oxidation chamber 14 or the secondary
oxidation chamber 16 drops below a predetermined level.
The ignition burner 18, mounted on the stationary wall
49, is slightly offset and directed toward the hearth for
efficient waste material ignition and to provide for the
effective introduction or additional heat as may be re-
quired to sustain combustion. Materials which are self-
sustaining during combustion (for example, materials
having a BTU value greater than 3000 BTU per pound and
with a moisture content less than 30 percent) will not
normally require additional heat from an external source
after startup.
When the temperature within the primary oxida-
tion chamber 14 reaches a predetermined high level the
0 temperature sensing device 88 within the latter chamber
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signals shutdown of the burner 18. In like manner theburner 24 responds to the temperature sensor 90 within
the secondary oxidation chamber 16 and is shutdown when
the temperature within the latter chamber reaches a pre-
determined high level. Alternatively, burner operational
cycle time may be controlled by one or more integral
timers associated with the controller 34. Depending upon
the materials being burned, combustion within the primary
oxidation chamber 14 can be controlled from a partially
pyrolytic condition to an oxidating one.
As previously noted, negative pressure is norm-
ally maintained in the primary oxidation chamber by draft
induced within the system. However, the butterfly valve
33 may be adjusted to control the flow of air into the
primary oxidation chamber from the conduit 53 whereby to
aid in maintenance of negative pressure within the pri-
mary oxidation chamber. Additional controls may be pro-
vided to assure maintenance of the desired negative
pressure. Thus, for example, appropriate controls may be
provided which respond to a pressure sensing device, such
as indicated at 97 in Fig. 2, located within the primary
oxidation chamber 14, to control the buttPrfly valve 33,
which controls the supply of air to the primary oxidation
chamber and/or the induced draft, as may be necessary to
maintain the desired negative pressure within the primary
chamber.
The angle of drum inclination is adjusted to as-
sure proper advance of waste material through the drum
38. The rate of drum rotation, which may be proportion-
ally controlled and which determines retention time of
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1210647
waste material within the primary combustion chamber 14,
is controlled by the drive motor 46. The drive motor 46
normally rotates the drum 38 in one direction, however,
the direction of drum rotation may be reversed, if nec
essary, to clear a jam within the primary oxidation
chamber. The rotary action of the drum 38 continuously
exposes new surfaces of burning waste to the hot hearth
and air as the burning waste travels down the incline to-
ward the discharge opening 43. This constant agitation
and the ability to control retention time within the pri-
mary combustion chamber 14 provides for efficient com-
bustion. Ash and other noncombustible residue is con
veyed to and through the discharge end of the drum 38 by
the combined action of drum rotation and incline and fall
into the ash receiver 20. The first baffle wall 62 ef-
fectively blocks the lower portion of the discharge open-
ing 43 and prevents the unburned residue from entering
the secondary oxidizing chamber.
The volatile products of combustion leave the
primary oxidation chamber 14 through the upper portion of
the discharge opening 43 and enter the secondary oxida-
tion chamber 16 through a first venturi region defined by
the upper portions of the downwardly diverging first and
second baffle walls 62 and 66 and indicated by the
numeral 67. The controlled partial pyrolisis in the pri-
mary oxidation chamber provides uncombusted gases which
when combined with air emitted from the burner or burners
in the secondary combustion chamber 16, such as the
burner 24, assure maintenance of oxidizing temperatures,
normally in the 1800 degree F to 2400 degree F range.
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~21~6~7
As the volatile gases enter the secondary oxida-
tion chamber 16 through the first venturi region 67, the
velocity of the moving gas stream, increases. Additional
air is or may be added to the gas stream in the first
venturi region 67, and for this reason the preheated air
from the ash receiver cooling system is introduced into
the secondary combustion chamber in the first venturi
region 67 through the conduit 84.
Ash and other particulate material entrained in
the gas which flows in a path along the second baffle
wall 66 tend to impringe upon the fourth baffle wall 72.
Separation of the ash and particulate material from the
gas ocurs at the point of impact allowing fallout
material to travel downwardly along the inclined fourth
baffle wall 70 and into the ash container 20 therebelow.
The velocity of the gases decrease as the gases
flow downwardly and away from the first venturi region 67
toward the ash container 20 which results in further
fallout of particulate material entrained within the gas
stream.
As the hot gases flow upwardly past the forward
end of the second baffle wall 66 and in the direction of
the third baffle wall 70, air introduced through the
slotted ceramic air header 74 mixes with the gases. The
slots in the header 74 direct streams of air into the gas
flow stream. The arrangement of the second and third
baffle walls 66 and 70 and the air header 74 tend to in-
duce a vortex in the region below the third baffle wall
70. The swirling gases in this region impinge upon the
baffle walls 66 and 70 and associated walls of the sec-
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12~647
ondary oxidation chamber causing further impact separa-
tion~
As the hot gases flow past the lower edge of the
third baffle wall 70 and into the upper portion of the
secondary oxidation chamber 16, a second vortex is in-
duced within the upper portion of the chamber 16 by the
particular arrangement of the baffle walls 66 and 70 and
the associated walls of the chamber. The spinning action
of the gases induced by the shape of the various regions
defined by the walls of the secondary oxidation chamber
and the baffles positioned therein causes centrifugal
separation of particulate matter and assures thorough
mixing of air and gases for efficient combustion. This
cyclonic and impact separation within the secondary oxi-
dizing chamber or afterburner permits achievement of high
efficiency, because of the low density and extremely high
temperature of the gases within the afterburner. The
tortuous path of the gases through the secondary combus-
tion chamber increases retention time for further opera-
tional efficiency.
In the illustrated system 10 the hot gases fromthe secondary oxidation chamber 16 flow through the duct
61 and the stack 28 and into the heat recovery boiler 26.
The illustrated boiler is a three-pass, horizontal, fire-
tube package boiler designed to operate at pressures up
to 150 PSI, however, heat exchangers of other kinds may
also be used to recover heat from the hot gases generated
by the incineration system 10.
In the illustrated system the gases are ducted
from the boiler 26 into the baghouse 30. Particles en-
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12~.(J647
trained in the gas stream enter the lower section of the
baghouse and pass through filter tubes (not shown).
Particulate materials are retained on the outer surface
of these tubes. Cleaned gases leave the baghouse through
associated exhaust duct and flow into the base of the
scrubber 30, wherein noxious gases such as chlorine, hy-
drogen chloride, and hydrogen sulfide, for example, are
removed from the exhaust stream by a gas absorption pro-
cess, well known in the art. After the moist gases have
passed through a demister section of the scrubber, where
final traces of moisture are removed, the dry gases leave
the scrubber and are ducted to the exhaust fan 28 and ex-
hausted to atmosphere. However, the incinerator unit,
hereinbefore described, is expected to produce such high
burning efficiency and low particulate carry-over that no
baghouse or other particulate filter device will be re-
quired for the majority of waste material processed. It
is expected that the illustrated incineration unit will
meet current federal environmental requirements of .08
grains per dry standard cubic foot of gas correlated to
12 percent CO2 when processing waste materials of classi-
fication types 0, 1, 2, 3 and 4.
The rate at which the combustable waste material
is fed into the drum 36 and the rate at which the
material is advanced through the drum to its discharge
end is preferably controlled in response to trends within
the system, or more specifically, within the primary and
secondary oxidation chambers. Thus, for example, if the
temperature within the incinerator 10 is rising the con-
trol system will respond to reduce the feed rate of the
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~Z~ 47
auger/shredder 22 and/or reduce the rate of rotation thedrum 38. By stopping the drum 38 or reducing its rate of
rotation the unburned materials in the drum are quieted
so that a layer of ash forms on the material to insulate
it against oxygen and heat~ Conversely, if the tempera-
ture within the incinerator 12 is declining the sensors
88 and 90 associated within the control system may re-
spond by altering the rate of waste feed and/or drum
rotation and/or by operating one or both of the burners
18 and 24, as may be necessary to achieve balance within
the system. Further control is or may be achieved by the
utilization of an oxygen or gas analyzing device, such as
indicated at 94 for monitoring the gases leaving the
secondary combustion chamber 16. This gas monitoring
device may, for example, be arranged to control intro-
duction of makup air into either or both combustion
chambers, so that additional air will be introduced when
an oxygen deficiency is indicated or the air supply re-
duced when excess oxygen is present. Further refinement
of the control system is achieved by utilization of a
computer 96 for analyzing trends/ averaging results, and
sequencing equipment operation. The computer 96 may be
coordinated with sensor selection, modified by programmed
data based upon known characteristics of the material
being processed as, for example, its BTU value per pound,
density and moisture content. Thus, the incinerator
system 12 may be controlled to provide substantially uni-
form operational characteristics and high efficiency
despite widely varying characteristics of the waste
material processed.
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64~7
In Fig. 11 there is shown a portion of another
incinerator system indicated generally at lOb~ The
system lOb is similar in many respects to the system 10,
previously described, and each part similar or substan~
tially identical to a part previously described bear the
same reference numeral as the corresponding previously
described part and a letter "b" suffix and will not be
hereinafter further described.
The illustrated system lOb includes an incinera-
tor indicated generally at 12b which has a rotary primary
oxidation chamber 14b and a stationary vertical secondary
oxidation chamber 16b. The incinerator 12b differs from
the previously discussed incinerator 12 in ~he construc-
tion and arrangement of the wall of the secondary oxida-
tion chamber 16 and in the arrangement of the baffle wall
62a located within the latter chamber. Specifically, the
secondary chamber 16b has a metal outer shell or exterior
wall 98 and and a liner or interior wall 99 made from re-
fractory material. A passageway 100 is defined between
the exterior wall 98 and the interior wall 99 at the rear
of the secondary oxidation chamber housing and communi-
cates with an ash cooling passageway 82b and with the
secondary oxidation chamber 16b to supply preheated air
to the latter oxidation chamber. Another passageway 84b
is formed between the exterior wall 98 and the interior
wall 99 in at least one of the sidewalls of the secondary
oxidation chamber housing and communicates with the ash
cooling passageway 82b and the secondary oxidation
chamber 16b near the upper part of the discharge opening
0 43b, substantially as shown in Fig. 11.
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12~6~
The baffle wall 62b has a lower portion which isgenerally vertically disposed and extends upwardly from a
position below the aischarge opening 43b. The baffle
wall 62b further includes an upper portion which is join
ed to the lower portion at a position below the center of
the drum discharge opening 43b and which extends upwardly
and in the direction of the discharge opening to a posi-
tion above the center of the discharge opening. The
first baffle wall and the second baffle wall converge in
a direction away from the discharge opening 43b and de-
fine a first venturi region 67b therebetween. Air
emitted from the passageway 100 enters the gas stream
from the first venturi region 67b, substantially as shown
in Fig. 11.
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