METHOD AND APPARATUS FOR AGGLOMERATING FINELY DIVIDED AGGLOMERATIVE MATERIALS IN A ROTATING DRUM

METHODE ET APPAREIL POUR AGGLOMERER, DANS UN TAMBOUR ROTATIF, DES PARTICULES AGGLOMERABLES FINEMENT DIVISEES

English Abstract

TITLE
METHOD AND APPARATUS FOR AGGLOMERATING
FINELY DIVIDED AGGLOMERATIVE
MATERIALS IN A ROTATING DRUM
ABSTRACT OF THE DISCLOSURE
A rotary drum assembly includes separate agglomerating
and hardening drums that are rotated independently of each other.
The agglomerating drum has a generally cylindrical configuration
with an inner cylindrical wall. A scraper is rotatably position-
ed within the agglomerating drum in spaced relation to the inner
cylindrical wall with its axis spaced from the axis of the drum.
The scraper has a tubular body portion with a plurality of
parallel rows of blades extending radially therefrom. Each of
the rows extends lengthwise along substantially the entire
length of the scraper body portion and follow a helical path
having a angle turn about the axis of the tubular body portion.
The rows of blades thus make a single convolution about the
scraper body portion. Drive means are provided to synchronously
rotate the agglomerating drum and scraper with the scraper
arranged to rotate in a direction opposite to the direction of
rotation of the drum. The scraper is also arranged to rotate
at a preselected and different speed relative to the speed of
the drum. Agglomerative material is introduced into the rotating
agglomerating drum and forms a layer of agglomerative material
on the drum inner cylindrical wall. The scraper is rotated in a
direction opposite to the direction of rotation of the agglomerat-
ing drum and at a preselected synchronous speed with the agglom-
erating drum. The parallel rows of blades on the scraper form
a plurality of spaced elongated generally longitudinal ridges
and valleys in the layer of agglomerative material on the drum

cylindrical wall. The ridges have a slight arucate configuration
and form less than a single convolution throughout the entire
length of the agglomerating drum. The spaced elongated ridges
in the layer of agglomerative material extend lengthwise in the
drum substantially parallel to the axis of the drum and serve as
longitudinally extending lifters to mix and agitate other
particulate agglomerative materials introduced into the drum by
lifting portions of the other particulate agglomerative material
from the underside of the bed and depositing the material on the
upper surface of the bed. This type of mixing promotes the
formation of agglomerates having a preselected relatively narrow
size consist. The synchronous rotation of the scraper removes
agglomerative material deposited on the surface of the elongated
ridges and valleys formed in the layer of agglomerative material
so that the desired ridge and valley configuration is maintained
in the layer of agglomerative material.

Claims

The embodiments of the invention in which an exclu-
sive property or privilege is claimed are defined as follows:
1. A method for agglomerating finely divided agglomerative
material comprising, feeding finely divided agglomerative material
into a substantially horizontal rotating drum having an inner
wall, said drum having a longitudinal axis and said drum arranged
to rotate about said longitudinal axis, depositing a layer of
said finely divided agglomerative material on said drum inner
wall, rotating a longitudinally extending scraper in said drum
in a direction opposite to the direction of rotation of said
drum and in fixed timed relation to the rotation of said drum
to form a preselected number of alternating longitudinally
extending ridges and valleys in said layer according to the
following formulas
<IMG>
where: N = a whole number and number of ridges formed
b = number of scraper blades
U1 = drum speed, rpm
U2 = scraper speed, rpm
forming a plurality of elongated alternating and longitudinally
extending ridges and valleys in said layer, said ridges and val-
leys extending substantially lengthwise along said drum inner
wall and substantially parallel to said drum longitudinal axis,
and maintaining said same ridges and same valleys so formed in
said layer deposited on the drum inner wall while rotating said
drum and forming agglomerated from other finely divided agglom-
erative material introduced into said rotary drum.
- 24 -

2. A method for agglomerating finely divided agglomerative
material as set forth in claim 1 which includes, forming a bed
of other finely divided material in said drum, rotating said drum
and forming an upper inclined surface on said bed, moving said
longitudinally extending ridges and valleys under said bed and
lifting a portion of said other agglomerative material adjacent
said drum inner wall with said longitudinally extending ridges
and valleys and thereafter depositing the lifted portion of said
other agglomerative material on the upper inclined surface of
said bed.
3. A method for agglomerating finely divided agglomerative
material as set forth in claim 1 which includes, maintaining the
rotation of said scraper in said drum at said fixed timed rela-
tion to the rotation of said drum to maintain the pattern of
ridges and valleys in said layer while forming agglomerates from
other finely divided material.
4. A method for agglomerating finely divided agglomerative
material as set forth in claim 1 which includes, controlling the
ratio of speeds of said rotating drum and said rotating scraper
to control the height and number of ridges and valleys formed in
said layer.
- 25 -

5. A method for agglomerating finely divided agglomerative
material as set forth in claim 4 in which, the scraper is rotated
at a speed twice the speed of the rotating drum to thereby form
four ridges and four valleys in said layer.
6. A method for agglomerating finely divided agglomerative
material as set forth in claim 1 in which, said elongated ridges
and valleys have a lengthwise arcuate configuration in the form
of a helix having less than one convolution throughout the length
of the drum.
7. A method for agglomerating finely divided agglomerative
material as set forth in claim 1 in which, said finely divided
agglomerative material includes bituminous coal and char heated
to an elevated temperature before being introduced into said
rotating drum.
8. Apparatus for agglomerating finely divided agglomerative
material comprising, a cylindrical rotary drum having a longitud-
inal axis and an inner wall, means to rotate said cylindrical
drum about said drum longitudinal axis at a preselected speed
and deposit a layer of finely divided agglomerative material on
said drum inner wall, an elongated rotary scraper having a body
portion with a longitudinal axis, said rotary scraper positioned
- 26 -

Claim 8 - continued
in said cylindrical drum in spaced relation to said cylindrical
drum inner wall with said scraper body portion longitudinal axis
spaced from said drum longitudinal axis, blade means extending
radially outwardly from said scraper and extending lengthwise
thereon, and means to rotate said rotary scraper in a direction
opposite to the direction of rotation of the drum in timed rota-
lion to the rotation of the drum and provide relative movement
between said rotary drum inner wall and said scraper blade means
to form a plurality of elongated alternating and longitudinally
extending ridges and valleys in said layer of agglomerative mater-
ial deposited on said drum inner wall, said rotary scraper arranged
to remove other finely divided agglomerative material deposited
on the surface of said ridges and valleys formed in said layer
of agglomerative material.
9. Apparatus for agglomerating finely divided agglomerative
material as set forth in claim 8 which includes, means to provide
synchronous rotation between said cylindrical rotary drum and
said rotary scraper.
10. Apparatus for agglomerating finely divided agglomerative
material as set forth in claim 8 in which, said blade means includes
a plurality of parallel rows of blades spaced around the periphery
of said rotary scraper.
- 27 -

11. Apparatus for agglomerating finely divided agglomerative
material as set forth in claim 10 in which, said plurality of
parallel rows of blades includes two rows of blades positioned
in opposed relation to each other on said rotary scraper, said
means to rotate said rotary scraper arranged to rotate said
rotary scraper at twice the speed of rotation of the cylindrical
rotary drum to thereby form four ridges and four valleys in said
layer of agglomerative material deposited on said drum inner
wall.
12. Apparatus for agglomerating finely divided agglomerative
material as set forth in claim 11 in which, said parallel rows
of blades having an arcuate configuration in the form of a helix
having a single turn about the axis of said scraper body portion
to thereby form arcuate parallel longitudinally extending ridges
and valleys in said layer of finely divided agglomerative
material.
13. Apparatus for agglomerating finely divided agglomerative
material as set forth in claim 8 in which, said layer of agglom-
erative material is a relatively rigid layer of carbonaceous
material formed from the agglomeration of finely divided coal
and finely divided char.
- 28 -

14. Apparatus for agglomerating finely divided
agglomerative material as set forth in claim 8 which includes,
positioning said rotary scraper within said rotary drum at a
location in a quadrant of said drum diametrically opposite from
the quadrant of said drum occupied by said agglomerative material
during rotation of said drum.
29

Description

4~;1
BACKGROUND OF THE IN~IENTION
1. Field of the Invention
This invention relates to a method and an apparatus for
agglomerating finely divided agglomerative materials in a
rotating drum and more particularly to a method and an apparatus
for agglomerating finely divided coal particles and finely
divided particles of carbonaceous residue in a rotating drum
to form carbonaceous agglomerates.
2. Description of the Prior Art
The procesq for making formcoke, as described in
United States Patents 3,073,751; 3,401,089 and 3,562,783, in-
cludes introducing particulate bituminous coal and finely divided
char (the solid carbonaceous residue of coal which has been
distilled at a temperature of between 800F. and 1400F.) in a
rotary retort. Depending on the type of coal employed and the
ratio of coal to char, pitch may also be added as a binder to
increase the strength of the agglomerates formed in this process.
Preferably, the particulate coal and finely divided char are
heated to an elevated temperature before they are introduced into
the rota~y retort so that the constituents supply as sensible
heat substantially all of the heat required to achieve the
desired temperature for agglomerating the carbonaceous materials.
During the agglomeration process the retort is rotated
to effect intimate mixing of the constituents and tumbling of
the agglomerates as they are formed. As the constituents are
mixed in the retort the coal particles are further heated to such
extent that partial distillation of the coal particles occurs,
e~olving tar and forming a loosely coherent plastic sticky mass
in the retort. ~ere a pitch binder is employed it further con-
tributes to the agglomeration of the particulate material within

~4~1
the retort.
It is believed that the loosely coherent plastic mass
formed in the rotary retort breaks up during tumbling into
relatively fine plastic particles. Growth of the plastic
particles is attained by a snowballing type of tumbling or
rolling action on the upper inclined exposed surface of the
plastic mass of particulate material in the retort. Repeated
tumbling or rolling of the particles causes the continued growth
of the plastic particles into agglomerates. The agglomerates
continue to grow until the binder evolved by the coal particles
and the pitch binder, if employed, loses its plasticity. There-
after, the agglomerates rigidify and the growth process is stopped.
The agglomerates recovered from the agglomerating retort are
thereafter calcined at an elevated temperature between 1500F.
and 1800F. and formcoke is obtained that has strength and
abrasion resi~tance that is equal or superior to that of conven-
tional blast furnace coke. One of the objectives of the above
described formcoke process is to form clo~ely sized agglomerates
having a suitable size range as, for example, a size range of
between 3/4" x 2" or a size range of between l" x 3". Oversized
agglomerates, i.e. agglomerates having a size greater than the
desired size, and undersizad agglomerates, i.e. agglomerates
having a size less than the desired size, may not be suitable
for use in a conventional blast furnace or other conventional
metallurgical processes.
It has been discovered that, in conventional sized
retorts, agglomerates of a suitable size range can be obtained
in shallow beds where the ratio of the absolute bed depth of the
particulate material to the diameter of the retort is maintained
below a critical value. The absolute bed depth designates the
true dimensional depth of the bed occupied by the carbonaceous

~VI~
material within the rotary retort~ It has been found where the
ratio of absolute bed depth to retort diameter is maintained
below the critical ratio (shallow bed) substantially all of the
agglomerates have a size less than 4" and a substantial portion
of the agglomerates have a suitable size range. Where, however,
the ratio of absolute bed depth to retort diameter is increased
above the critical ratio to form a deep bed the agglomerate
product formed has a substantial quantity of agglomerates with a
size greater than 4" and a reduced quantity of agglomerates with
a suitable size range.
From an economic standpoint it is desirable to use
retorts having as large a diameter as possible and to maintain
as deep a bed of carbonaceous material as possible in the rotat-
ing retort. With these conditions, however, it is also essential
that the size range of the agglomerate product formed is within
the suitable size range.
In United States Patents 3,368,012 and 3,460,195 there
i~ disclosed a rotary retort for agglomerating carbonaceous
material in a deep bed in which the ratio of absolute bed depth
to retort diameter may be increased above the aforementioned
critical ratio and a substantial yield of agglomerates of
suitable size range is obtained. In accordance with the teaching
of these patents, preheated particulate bituminous coal and
finely divided char are agglomerated in a rotary retort that has
a plurality of longitudinally extending rakes secured to the
rotary retort inner cylindrical wall. Each of the ra~es has a
plurality of tines extending inwardly toward the center of the
rotary retort and the tines have a length between l/~ and l/3
fhe diameter of the rotary retort. The tines on the ra~es are
~0 spaced from each other at a preselected distance to relieve the
compaction pressure exerted on the bed of carbonaceous material

~8;~46~
and to control the size of the agglomerates formed in the retort.
An agglomerate product having a suitable size range is obtained
even when the ratio of absolute bed depth to retort diameter is
increased substantially above the ratio previously considered
the critical ratio to obtain an acceptable yield of agglomerates
having a suitable size range.
During the agglomeration process the carbonaceous
materials have a tendency to adhere as a sticky plastic mass
to the inner wall of the rotary retort and to the rake tines.
Separate apparatus is required to remove the accumulation of
agglomerated carbonaceous materials adhering to the retort wall
and to the rake tines. Because of the tine spacing, difficulty
i8 encountered in removing the deposits of carbonaceous material
on the retort wall and on the rake tines. Further, a substantial
amount of energy is required to rotate the retort while the
apparatus, such as a fixed scraper device, removes the
carbonaceous deposits from the retort inner wall and rake tines.
It i8 also known in the agglomeration of agglomerative
materials that a smooth inner cylindrical wall of the rotary
drum or retort is not the optimum surface for forming agglomerates.
Various types of metallic lifters for the agglomerative material
within the rotary drum have been proposed as, for example, the
lifter6 disclosed in United States Patents 3,124,338; 2,695,221;
2,926,079; 2,213,~56 and 3,68g,044. These lifters are not
suitable, however, where the agglomerative material has a
tendency to adhere to the inner wall of the drum. After a short
period of time a layer of the agglomerative material is formed
on the wall of the drum to a depth that i9 equal ~o or greater
than the height of the metallic lifters. This layer of agglo-
merative material reduces and soon eliminates the effect of the
metallic lifters.

~38;~;~
United States Patent 3,348,262 discloses a fixed
scraper for controlling the thickness of the layer or coating of
agglomerative material deposited on the inner surface of the
rotating drum. The layer has a uniform thickness and a gener-
ally relatively smooth surface. United States Patents 2,697,068
and 3,316,585 disclose rotary scrapers positioned within the
rotary drum that are arranged to continuously remove agglomera-
tive material from the inner wall of the drum and maintain a
layer of the agglomerative material of a preselected uniform
thickness on the wall of the drum. It is stated the layer of
agglomerative material provides a surface that is superior to a
smooth cylindrical wall.
United States Patent 2,831,210 discloses a cutter bar
positioned within the rotary drum adjacent the inner wall of the
drum. The cutter bar has spaced teeth extending toward the drum
inner wall. The cutter bar is arranged to reciprocate
longitudinally relative to the drum wall and cut a series of
allochiral left and right hand helical grooves in the layer of
agglomerative material deposited on the drum inner wall. The
rate of reciprocation of the cutter bar and the speed of rota-
tion of the retort are controlled so that the helical grooves do
not track each other on successive strokes of the cutter bar and
thus provide a controlled roughness to the surface o~ the layer
of agglomerative material on the drum inner wall. It is stated
the roughened surface of the layer is superior to a smooth surface.
United States Patent 2,778,056 discloses an agglomerat-
ing drum with a scraper positioned therein. The drum and scraper
are arranged to rotate at preselected synchronous speeds with the
scraper rotating in a direction opposite to the direction of
drum rotation. The scraper disclosed is in the form of a l'ribbon"
flight" conveyor and forms multiple convolutions of helical
grooves in material adhering to the inner surface of the drum.
-- 7 --

1~8'~4~;1
The convolutions of the main portion of the scraper have the
direction of a right handed thread ~o that the multiple
convolutions foxmed in the surface of the material adhering
to the inner surface of the drum are 80 inclined that loose
material in the groves tends to move back toward the inlet
of the drum. Adjacent the end~ of the drum the direction of
thread rotation of the scraper i~ rever~ed to minimize 8pil-
lage of the material fed ~nto the drum and also accelerate the
discharge of the agglomerates formed. The helical groves
formed in the material adhering to the inner surface of the
drum extend generally circumferentially around the drum 80 that
the material w~thin the drum tends to roll or slide downwardly
wlthin the groove~ and be carried back towards the entrance of
the drum. ~he rldge~ formed between the grooves, because of
thelr generally circumferential arrangement around the inner
~ur~ace of the drum, do not functlon a~ lifter~ to mlx the
matorial wtthin the drum.
There t~ a neod for method and apparatus to control
the ~urface configuration of the layer of agglomerat~ve mater-
i~l depo~ted on the drum ~nnex wall and provide elongatedr~dge~ and ~a}leys that ~erve a~ generally longitudinal l~fters
~--~ --8--

~38;~46~
~o that other agglomerative material fed into the drum i~ lifted
by the ridges formed in the deposited material and adequately
mixed and agglomerates of a preselected size range are formed.
SUMMARY OF THE INVENTION
This invention relates to a method and an apparatu~
for agglomerating finely divided agqlomerating material in a
rotating drum. The method includes feeding finely divided
agglomerative material into a substantially horizontal rotating
drum having an inner wall. The drum ha~ a longitudinal axis
and i8 arranged to rotate about the longitudinal axi~. A layer
of ~inely divlded agglomeratlve material i8 deposited on the
drwm inner wall. A longitudinally extending scraper i~ rotated
~n tho drum in a diroction oppo~ite to the dlrectlon of rota-
tlon of the drum and in ~ixed timed relation to the rotation
ot the drum to form a preselected number of alternating longi-
tudinally extondin~ ridge~ and valley~ according to the following
for~ul~s
N - b U2
Ul
wheres N ~ a who~e number ~nd number of ridge~ formed
b ~ number o~ ~craper blades
Ul ~ drum ~peed, rpm
U2 ~ ~craper spped, rpm.
'~ ,1~;

~08'~
A Plurality of elongated alternating and longitudinally
extending ridge~ and valleys are formed in the làyer. The
ridges and valleys extend substantially lengthwi~e along
the drum inner wall and ~ubstantially parallel to the drum
longitudinal axi9. The 80 formed same ridges and valleys
are maintained in the layer depo~$ted on the drum inner
wall while rotating the drum and formlng agglomerates from
other material ~ntroduced into the rotary drum.
The apparatus for agglamerating the finely divided
agglomorative material includes a cylindrical rotary drum having
a longitudinal axis and an inner wall. Mean~ are provided to
rotate the drum about $t~ longitudinal axi~ at a pre~elected
~p--d and dopo~$t a layer of the f$nely divided agglomeratl~e
~ater~al on the drum inner wall. An elongated rotary ~craper
ha~ a body portion and a longitudinal axls. The rotary scraper
i~ po~ition~d ~n the cyllndrical drum in ~paced relation to
the cyl~ndrtcal drum lnner wall wlth the ~craper body portion
longitudinal ax~s spaced from the longitudinal axis of the rotary
drum. Blade mean~ extend rad~ally outwardly from the ~craper
r` ~ - 9A -

4~;~
and extend lengthwise thereon. Means are provided to rotate
the rotary scraper in a direction opposite to the direction of
rotation of the drum in timed relation to the rotation of the
drum and provide relative movement between the rotary drum
inner wall and the scraper blade means to form a plurality of
elongated alternating and longitudinally extending ridges and
valleys in the layer of agglomerative material deposited on the
drum inner wall. The rotary scraper is further arranged to
remove other finely divided agglomerative material deposited
on the surface of the ridges and valleys formed in the layer of
agglomerative material.
The above method and apparatus are particularly suit-
able for agglomerating finely divided carbonaceous materials at
an elevated temperature and forming a substantial ~uantity of
agglomerates having a preselected size range. The carbonaceous
materials at an elevated temperature are introduced into a
rotating drum which serveg as a retort and a layer of carbo-
naceous material is deposited on the retort inner cylindrical
wall. A plurality of longitudinally extending spaced ridges
and valleys are formed in the layer of carbonaceous material
with the ridges and valleys extending substantially parallel
to the retort longitudinal axis. After the binder in the carbo-
naceous particles is evolved the layer of carbonaceous material
loses its plasticity and rigidifies to form a relatively rigid
layer with ridges and valleys formed therein.
As other finely divided carbonaceous material is
introduced into the rotating retort the car~onaceous material
forms a bed in the retor_ with an upper surface extending up-
wardly in the direction of rotation of the retort. The
longitudinally extending ridges of carbonaceous material formed
on the inner wall serve as lifters to convey or lift a portion

~8Z4ti~
of the finely divided carbonaceous material adjacent the retort
inner wall in the direction of retort rotation and deposit at
least a portion of this carbonaceous material on the upper
surface of the bed to both intimately mix the finely divided
carbonaceous material in the retort and deposit particles on
the upper inclined surface of the bed. Repeated tumbling of
the particles and partially formed agglomerates on the upper
surface of the bed causes continued growth to form agglomerates
of a preselected size. ~ny finely divided carbonaceous material
deposited on the exposed surface of the ridges and valleys is
continually removed therefrom so that the ridges and valleys
of a preselected configuration are maintained during the
agglomeration process. Where desired metallic lifters, such as
elongated metallic members of proper dimension, may be secured
to the retort inner wall to provide support for the longitud-
inally extending ridges of carbonaceous material and also serve
a~ an integral portion of the lifters.
With the above arrangement a plurality of spaced
elongated ridges are formed on the inner wall of the rotating
retort to serve as lifting or mixing devices for the finely
div~ded carbonaceous material. The scraper posit~oned in the
retort that initially shaped the elongated longitudinally
extendlng ridges and valleys in the layer of carbonaceous
material further removes other agglomerative carbonaceous
material that may be deposited on the surface of the ridges and
valleys ~o that the layer of carbonaceous material retains its
ridge and valley configuration during the agglomeration process.
Accordingly, the principal object of this invention is
to provide a method and an apparatus for forming elongated
longitudinally extending ridges and valleys in a layer of
agglomerative material deposited on the inner wall of a rotary
drum,

4~i1
Another object of this invention is to provide a
method and an apparatus for maintaining a plurality of spaced
longitudinally extending lifters formed of agglomerative
material on the inner wall of a rotary drum.
These and othex objects and advantages of this
invention will be more completely disclosed and described in
the following specification, the accompanying drawings and the
appended claims.
BR~EF DESCRIPTION OF THE DRAWINGS
Figure 1 is a top plan view of a rotary drum assembly
having separate balling and hardening drums.
Figure 2 is a view in side elevation of the rotary
drum assembly, illustrating the rotary scraper rotatably
supported in the balling drum.
Figure 3 is an enlarged view of the balling drum in
side elevation and section, illustrating the support and drive
for the rotary scraper and schematically the longitudinally
extending rows of scraper blades.
Figure 4 is a view in section taken along the line
IV-IV of Figure 3, illustrating in detail the rotary scraper
with two rows of scraper blades extending radially therefrom.
Figure 5 is a fragmentary view in section taken along
the line V-V of Figure 4, illustrating a scraper blade element
of a row of scraper blades adjustably secured to the blade
support.
Figure 6 is a view in end elevation of the balling drum
feed and illustrating the relative position of the rotary
scraper in the balling drum.
Figure 7 is a diagrammatic view in section and in
elevation of the balling drum, illustrating schematically the

4~
rotary scraper having two rows of ~lades within the balling
drum rotating in a direction opposite to the direction of drum
rotation and the manner in which elongated generally longitud-
inally extending ridges and valleys are formed in a layer of
agglomerative material on the inner wall of the drum with the
ridges serving as generally longitudinal lifters for the
particulate agglomerative material within the balling drum.
Figure 8 is a graphical representation of the height
of the ridges attainable at various ratios of scraper speed to
drum speed with a drum having an effective diameter of 141" and
a scraper having a diameter of 46.1".
INTRODUCTION
Throughout the specification the rotary cylindrical
drum will also be referred to as a rotary retort or kiln. The
terms rotary retort or kiln are intended to designate a
cylindrical drum in which partial distillation of one or more of
the constituents takes place during the agglomeration process.
Although the preferred method includes the partial distillation
of coal during the agglomeration process, it should be under-
stood that it is not intended to limit the invention to such aprocess and the invention may be practiced with materials that
agglomerate at ambient temperature. It is not intended by
illustrating and describing the rotary cylindrical drum assembly
herein as including a separate agglomerating drum and a separate
hardening drum to be limited to such an assembly. The invention
may also be practiced in a single cylindrical drum assembly.
~he agglomerating drum in this specification is also referred to
as a balling drum.
Referring to the drawings and particularly Figures 1
and 2 there is illustrated a rotary drum assembly generally
1, _

~4~
designated by the numeral 10 that includes separate balling and
hardening drums designated by the numerals 12 and 14,
respectively. The balling drum 12 has a generally cylindrical
configuration with a front feed or inlet opening 16, a rear
discharge opening 18 and a longitudinal axis 15 about which the
balling drum 12 rotates. The discharge opening 18 of drum 12
extends into a stationary housing 20. The hardening drum 14
also has a generally cylindrical configuration with an inlet
opening 22 that extends into the fixed stationary housing 20
and a discharge opening 24 with a trommel screen 26 connected
thereto. The trommel screen 26 is enclosed by a housing 28 that
has outlets 30 and 32 for agglomerates separated according to
size by the trommel screen 26. As shown in Figure 3, the dis-
charge opening 18 of balling drum 12 extends into the inlet
opening 22 of hardening drum 14 so that agglomerates formed in
the balling drum 12 are discharged directly into the hardening
drum 14. The balling drum outlet opening 18 has an annular dam
34 that controls the inventory of agglomerative material and
agglomerates in the balling drum 12. A sealed housing 36
surrounds the balling drum inlet opening 16 and, as illus~rated
in Figure 6, suitable inlets 38 and 40 are provided in the
housing 36 for introducing agglomerative material, such as coal
and char, into the balling drum 12.
As illustrated in Figures 1 and 2, the balling drum 12
has an annular gear 42 secured thereto that meshes with a drive
gear 44 connected to a suitable drive means designated by the
numeral 46. The ~allinq drum 12 has a pair of annular metallic
tires 48 and 50 that rotatably support the drum 12 on roller
assemblies 52 and 54 and limit axial movement of balling drum 12.
The roller as~emblies 52 and 54 and the front housing 36 are
supported on a platform 58 that is movable vertically to change

- ~ ~4t;i
the angle of inclination of the balling drum 12. The balling
drum longitudinal axis 15, i.e. the axis of rotation, is
substantially horizontal and where desired the platform 58 may
be utilized to incline the balling drum 12 axis of rotation to
control the residence time of the material therein. The
hardening drum 14 has a similar annular gear 60 secured thereto
that meshes with a drive gear 62. A separate drive means 64
rotates the hardening drum 14 at a preselected speed that is
independent of the speed of rotation of the balling drum 12.
Annular metallic tires 66 and 68 support the hardening drum 14
on roller assemblies 70 and 72 to permit rotation of the hard-
ening drum 14 by the drive means 64 and prevent axial movement
of the hardening drum 14 during rotation thereof.
Referring to Figures 3 and 6, a scraper generally
designated by the numeral 74 has a longitudinal axis 75 and is
rotatably positioned within the balling drum 12 in spaced
relation to the drum ~nner wall 76. The rotary scraper 74 is
located above a horizontal plane extending through the longi-
tudinal axis 15 of the drum 12 and, as viewed in Figure 6, on
the left side of a vertical plane extending through the
longitudinal axis of drum 12. With this arrangement, the rotary
scraper 74 is positioned in the upper left quadrant of the
cylindrical ope~ing in the balling drum 12 as defined by the
inner ~rum wall 76 and is arranged to rotate about its longi-
tudinal axis 75. As later explained, the position of the rotary
scraper is determined by the direction o~ drum rotation. For
example, as viewed in Figures 6 and 7, drum rotation is in a
counter-clockwise direction as indicated by the directional
arrow 78 and the rotary scraper 74 is positioned in the upper
quadrant opposite from the inclined bed of agglomerative material
formed within balling drum 12.

J~4~1
The rotary scraper 74 has a tubular body portion 80
with a front end shaft 82 and a rear end shaft 84 secured
thereto and extending therefrom. It should be understood that
the body portion 80 may also be solid and of a configuration
other than a cylinder. The body portion 80 may have a smaller
transverse dimension than illustrated as long as the body por-
tion has sufficient strength to rotatably support the blades.
The front end shaft 82 extends through a suitable seal 86 in
the housing 36 and is rotatably supported in a bearing 88
mounted on the housing 36. The front end shaft 82 has a sprocket
90 nonrotatably secured thereto and the front end shaft is
supported in another bearing 94 which, in turn, is supported on
a fixed beam 92. The rear end shaft 84 is rotatably supported
in a bearing 96 which is supported on a fixed support beam 98.
The beam 98 is secured to a portion of the fixed housing 20 en-
closing the balling drum outlet opening 18 and the hardening
drum inlet opening 22. With this arrangement the scraper 74 is
rotatably supported wlthin the balling drum 12 and is supported
at its end portions in bearings.
The drive for rotating the scraper 74 includes a drive
motor 100, illustrated in Figures 3 and 6, connected through a
suitable speed reducer 102 to a drive sprocket 104. An endless
chain 106 i8 reeved about the sproekets 90 and 104 and is
arranged to rotate the scraper 74 in a direction opposite to the
direction of rotation of the drum 12 as indicated in Figures 3,
6 and 7 by the directiona} arrow 56. Suitable control means are
provided to rotate the ~craper 74 in synchronous relation with
the balling drum 12 so that the scraper 74 rotates at a pre-
~elected speed ratio with the balling drum 12. Where desired
the control means can be arranged to change the relative speeds
of the scraper or the drum to obtain other speed ratios between
- 16 -

4~i~
the scraper and the drum so that, as later discussed, other
ridge and valley configurations may be obtained.
The scraper 74 has two rows of scraper blades gener-
ally designated by the numerals 108 and 110 secured to the
outer surface of the tube 80. The rows of blades include
separate blade assemblies that have a blade support member 116
rigidly secured to the surface of the tube 80 as by welding or
the like. Separate blades or blade segments are secured to
the blade support members 116 by means of bolts 120. The blade
segments 118 have elongated slotted portions 122 that permit
radial adjustment of blade segments 118 on the blade support
members 116.
The rows of blades 108 and 110 extend parallel and
lengthwise along the tube 80 to form elongated continuous cut-
ting surfaces along substantially the entire length of the
scraper 74. In Figure 3 only the end portions of the rows of
blades 10~ and 110 are illustrated. The rows of blades provide
a continuous cutting surface that preferably follows an arcuate
helical path in which the helix has less than a single turn
about the axis 75 of the tube 80 throughout the length of the
scraper 74 as diagrammatically illustrated by the --~-- line
124 in Figure 3.
The scraper 74 thus has two separate rows of blades
extending lengthwise throughout substantially the entire length
of the scraper 74. The rows of blades follow a helical path
and pre~erably form a helix not exceeding a single turn about the
tube axis in which the rows of blades 108 are displaced to the
left about the axis 75 as viewed in Figure 3 between the front
and rear end of the scraper 74. It should be understood that
other blade configurations may be employed that have the rows of
blades arranged parallel to the longitudinal axis of the scraper

4~;1
tube 80 or form a helix with more than one turn about the tube
axis. The blade arrangement should be such, however, that the
ridges formed ~n the material adhering to the drum inner wall
extend longitudinally along the drum inner surface and are
substantially parallel to the axis of the drum. With this
arrangement the ridges formed by the blades serve as longitud-
inally extending lifters to lift and mix the material in the
drum.
It should also be understood that the number of rows
of blades secured to the outer surface of the tube 80 can be
increased or decreased as, for example, the scraper 74 can have
one, three or four rows of blades rather than two opposed rows
as illustrated. It is desirable, however, that the rows of
blades be equidistantly positioned on the periphery of the
scraper tube 80 to provide symmetrical ridges and valleys in
the layer of agglomerative material deposited on the balling
drum inner wall 76.
Referring to Figure 7, there is illustrated
diagrammatically the manner in which the rotary scraper 74 forms
ridges and valleys in a layer of agglomerative material deposited
on the inner wall 76 of balling drum 12 and the manner in which
the ridges serve as lifters to admix the agglomerative
constituent~sand aid in forming agglomerates of a preselected
size range from the agglomerative material.
To form a corrugated or scalloped surface with
longitudinally extending ridges and valleys on the wall of the
balling drum, agglomerative material is first introduced into
the balling drum. Where particulate ~ituminous coal, finely
divided char and pitch are the agglomerative cvnstituents, the
coal may be preheated to a temperature of between 400DF. and
625~F. which is below the temperature at which the surface of

`~8~
the coal particles becomes plastic and sticky. The char is
preheated to a temperature between 1000F. and 1200F. to
supply the sensible heat required for the agglomeration process.
The coal, char and pitch at the above elevated temperatures
are introduced into the balling drum 12 as the balling drum 12
is rotating in a counter-clockwise direction as illustrated in
Figure 7.
The agglomerative constituents are mixed by the
rotation of the drum 12 and heat is transferred from the char
to the coal particles and pitch and the agglomerative con-
stituents form a sticky plastic mass. A layer of the sticky
plastic mass is deposited on the inner surface 76 of balling
drum 12. The rotary scraper 74 is synchronously rotated in a
direction opposite to the direction of rotation of balling drum
12 and at ~wice the speed of the balling drum 12. At this
synchronous speed the rows of scraper blades 108 and 110
periodically move toward and away from the wall of the drum 12.
Because the rotation of the scraper is synbhronous
with the rotation of the drum at a ratio of 2 to 1, four
elongated ridges 130, 132, 134 ana 136 are formed in the layer
of agglomerative material 126. The rows of scraper blades are
so spaced from the drum wall 76 that the layer of agglomerative
material deposited on the drum inner wall 76 i8 continuous and
elongated valleys 138, 140, 142 and 144 are formed in the
agglomerative material between the ridges 130 - 136. While the
layer of agglomerative material is being deposited on the drum
wall 76 and is being shaped by the scraper 7~ the agglomerative
material in the layer is plastic and flexible. When the binder
associated with the coal and pitch loses its plasticity due to
the pyrolysis that takes place at the elevated temperature with-
in the drum the layer hardens and rigidifies to retain the
-- 19 --

longitudinally extending ridge and valley configuration above
discussed.
The material to be formed into agglomerates, pref-
erably the same material employed in forming the corrugated
or scalloped layer on the drum wall, may be introduced into
the drum while the layer is hardening or after the layer has
hardened. The agglomerative material is introduced on a
continuous basis into the rotating drum at a preselected rate
to form a bed of agglomerative material within the drum. The
bed is designated by the numeral 146 in Figure 7. Rotation of
the drum in the direction indicated by arrow 78 moves the bed
of agglomerative material upwardly along one side of the retort
to an extent that the top surface of the bed 146 has, for
example, an angle of repose of about 70. The angle of repose
is dependent on the speed of rotation of the drum 12. As the
drum 12 rotates the longitudinally extending ridges 130 - 136
in the layer 126 move under the bed of agglomerative material
and promote agitation of the bed. ~he agitation of the bed
includes top to bottom mixing whereby a portion of the agglom-
erative material in the bed adjacent the drum wall 76 is con-
veyed upwardly through the bed. The longitudinally extending
ridges further turn a substantial portion of this agglomerative
material in the portion conveyed by the longitudinally extending
ridges and valleys over and onto the bed top surface 14a.
Moving a portion of the agglomerative material up-
ward~y through the bed and turning a portion of the agglomerative
material over thoroughly admixes the agglomerative material
and also continuously deposits partially agglomerated agglom-
erates 152 on the bed upper surface 148 at the top portion 150
of bed 146. The partially agglomerated agglomerates 152 roll
down the bed upper surface 14 a and the partially agglomerated
- 20 -

agglomerates grow in size by picking up additional plastic
particles from the upper surface of the bed. In order to ob-
tain the above described bottom mixing of the agglomerative
material it is essenti~l that the ridges 130 extend longitud-
inally along the inner surface of the drum to be effective as
lifters. The angle of inclination of balling drum 12 conveys
the partially agglomerated agglomerates as they grow toward
the balling drum discharge opening 18. The partially agglom-
erated agglomerates continue to grow until the binder loses
its plasticity and full size agglomerates then harden and
rigidify. After the agglomerates harden no further growth
takes place. The agglomerates so formed are introduced into
the hardening drum where rotation of the hardening drum permits -
substantial completion of the pyrolysis of the agglomerative
constituents and relatively rigid hard agglomerates are with-
drawn from the hardening drum.
The agglomerative material in bed 146 because of its
pla~ticity has a tendency to adhere to the interior surface of
the layer of rigid agglomerative material deposited on the
drum inner wall 76. The scraper assembly 74, because of its
continued rotation at a preselected synchronous speed,
continuously removes the fresh deposit of agglomerative material
on the outer surface of the ridges and valleys while the newly
deppsited agglomerative material is in a relatively plastic
state to thereby maintain the configuration of ridges and va}leys
as illustrated in Figure 7. Where desired, metallic support
members may be secured to the drum inner wall and the ridge
portions 13~ - 136 formed therein. The metallic support
members provide structural support for the ridges and the
synchronous rotation of the scraper 74 prevents interference
between the metallic support members and the scraper blades.
- 21 -

~8;~4f~1
It may be desirable for certain agglomerative
conditions to vary the number and height of the ridges and
valleys around the periphery of the drum wall. Figure 8
illustrates the enlarged ridge height and the number of ridges
where two rows of blades are positioned on the scraper 74.
Thus, where it is desirable to obtain maximum ridge height
with the scraper rotating in a direction opposite to the
direction of rotation of the drum the ratio of scraper speed
to drum speed is about 2 to 1. Where a maximum of ridges are
desired the ratio of scraper speed to drum speed is increased.
Where the number of ridges or lifters is increased, the height
of the ridges or lifters decreases. For example, where the
ratio of scraper speed to drum speed is 6 to 1, twelve ridges
are formed around the periphery of the drum wall. The ridge
height is substantially reduced as compared with the height of
the ridges where only four ridges are formed on the drum wall 76.
Where more than two rows of blades are secured to the tube 80
the ridge height is reduced for the came ratio of scraper speed
to drum spe~d as is indicated in Figure 8 for three rows of
blades and four rows of blades.
With the previously described method, in order to
have the scraper blades form and maintain the same and the
d0sired number of longitudinally extending ridges and valleys,
it is essential that the product of the number of rows of blades
on the scraper multiplied by the ratio of scraper revo}utions to
drum revolutions per unit time is a whole number.
b U2
N =
wherein N = number of ridges formed
b = number of scraper blades
Ul = drum speed, rpm
U2 = scraper speed, rpm
- 22 -

` ~8'~
For example, with a scraper having two rows of
blades and the scraper rotating 2 times faster than the drum,
four longitudinally extending ridges and valleys are formed
and the rows of blades will sequentially move in timed relation
through the longitudinally spaced valleys without disturbing
the adjacent ridges.
Where twelve peaks are desired and the rotary scraper
has two rows of blades, the ratio of scraper speed to drum
speed must be 6, as exemplified by the following calculation.
N = 2 x 6
N = 12
It should be noted that it is also possible with the
above method and apparatus to control the thickness of the
layer and form ridges and valleys in the layer so deposited
on the drum inner wall. The blades on the scraper as they
rotate relative to the drum follow arcuate overlapping paths
through the layer and thu~ form the ridges and valleys above
d~scus~ed~
With the above method and apparatus it is now possible
to form lifters on the inner surface of the drum from the same
or substantially the ~ame material that is agglomerated in the
drum. After the lifters in the form of ridges are formed in
the layer of material deposited on the wall of the drum the
blades of the rotary scraper 74 remove the material that is
deposited on the surface of the ridges and valleys in the layer.