U.S. patent application number 14/636666 was filed with the patent office on 2015-06-25 for pyrolyzer furnace apparatus and method for operation thereof.
The applicant listed for this patent is NUCOR CORPORATION. Invention is credited to Richard A. WOLFE.
Application Number | 20150175889 14/636666 |
Document ID | / |
Family ID | 49156626 |
Filed Date | 2015-06-25 |
United States Patent
Application |
20150175889 |
Kind Code |
A1 |
WOLFE; Richard A. |
June 25, 2015 |
PYROLYZER FURNACE APPARATUS AND METHOD FOR OPERATION THEREOF
Abstract
A char making apparatus comprises a longitudinal pyrolyzer
furnace housing wherein coal-bearing material may be heated to a
temperature to fluidize volatile materials therein and plasticize
coal in the coal-bearing material. At least two rotatable drive
screws are laterally positioned and interleaved within the
longitudinal furnace housing and capable of conveying coal-bearing
materials through the pyrolyzer furnace housing, each drive screw
having a hollow drive shaft and a diverter positioned within the
drive shaft to provide heating to the coal-bearing material. A
heating jacket about the longitudinal furnace housing provides
additional heating to the coal-bearing material. Multiple
combustion chambers adjacent the heating jacket and hollow drive
shaft burn fluidized volatile materials and exhaust combustion
fluids through the jacket and shaft.
Inventors: |
WOLFE; Richard A.; (Banner
Elk, NC) |
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Applicant: |
Name |
City |
State |
Country |
Type |
NUCOR CORPORATION |
Charlotte |
NC |
US |
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|
Family ID: |
49156626 |
Appl. No.: |
14/636666 |
Filed: |
March 3, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13608703 |
Sep 10, 2012 |
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14636666 |
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11959581 |
Dec 19, 2007 |
8444828 |
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13608703 |
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60871863 |
Dec 26, 2006 |
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Current U.S.
Class: |
201/5 ;
201/15 |
Current CPC
Class: |
C10B 37/04 20130101;
B30B 11/00 20130101; C10J 2300/1207 20130101; C10B 45/02 20130101;
C10B 11/00 20130101; C10B 49/10 20130101; C10L 5/08 20130101; C10L
2290/28 20130101; C10J 2200/156 20130101; C10L 2290/24 20130101;
C10B 1/06 20130101; C10L 5/04 20130101; C10J 2300/1246 20130101;
C10L 2290/30 20130101; C10B 21/00 20130101; C10L 5/22 20130101;
C10B 57/04 20130101; C10J 2300/093 20130101; C10B 47/24 20130101;
F23G 2203/8013 20130101; C10J 3/007 20130101; C10B 47/44 20130101;
C10B 1/08 20130101; C10J 2300/1223 20130101; C10L 2290/02 20130101;
F23G 5/0273 20130101; C10B 7/10 20130101; C10J 2300/0973 20130101;
C10J 2300/0909 20130101; C10L 5/12 20130101; F23G 2201/303
20130101 |
International
Class: |
C10B 47/24 20060101
C10B047/24; C10B 37/04 20060101 C10B037/04; C10B 1/08 20060101
C10B001/08; C10B 57/04 20060101 C10B057/04; C10L 5/08 20060101
C10L005/08; C10B 7/10 20060101 C10B007/10; C10B 47/44 20060101
C10B047/44; C10B 11/00 20060101 C10B011/00; C10L 5/04 20060101
C10L005/04; C10B 21/00 20060101 C10B021/00; C10B 1/06 20060101
C10B001/06 |
Claims
1. A method for making char comprising the steps of: a. assembling
a longitudinal pyrolyzer furnace housing having at least two
rotatable drive screws laterally positioned and interleaved within
the longitudinal furnace housing, and capable of conveying
coal-bearing materials containing volatile material through the
pyrolyzer furnace housing, each drive screw having a hollow drive
shaft and a diverter longitudinally positioned within the drive
shaft, the diverter forming with an inner surface of each drive
shaft an inner passageway capable of directing heat flux to
adjacent coal-bearing materials moving through the pyrolyzer
furnace to fluidize the volatile material therein and plasticize
coal in the coal-bearing material; b. assembling a heating jacket
about the longitudinal furnace housing along at least a portion
thereof in fluid communication with combustion fluid from multiple
combustion chambers to provide heat flux from combustion fluid
moving through the heating jacket to adjacent coal-bearing
materials moving through the pyrolyzer furnace to fluidize the
volatile material in the coal bearing material and plasticize the
coal in the coal bearing material; c. assembling multiple
combustion chambers adjacent the longitudinal pyrolyzer furnace
housing capable of burning fluidized volatile material and, if
desired, other hydrocarbon fuels, and exhausting combustion fluids
through the inner passageway within the hollow drive shaft of the
drive screws and the heating jacket of the pyrolyzer furnace
housing to fluidize the volatile material in the coal bearing
material and plasticize the coal in the coal bearing material; and
d. rotating the drive screws to cause coal-bearing material
containing volatile materials to move through the longitudinal
pyrolyzer furnace housing to be heated by the heat flux from the
combustion fluid to fluidize volatile material in the coal-bearing
material and plasticize the coal in the coal-bearing material.
2. The method of making char as claimed in claim 1, where the flow
of combustion fluid through the inner passageways and heating
jacket are in the same direction as the movement of the
coal-bearing materials through the pyrolyzer furnace housing.
3. The method of making char as claimed in claim 1, further
comprising the step of: providing a turbulent flow of combustion
fluids through the inner passageways and the heating jacket having
a Reynolds Number greater than 4000.
4. The method of making char as claimed in claim 1, further
comprising the step of: tapering outer walls of the hollow shafts
of the drive screws downstream to cause the coal-bearing material
to be compressed as it moves through the pyrolyzer furnace housing
to compact the char before exiting the pyrolyzer furnace
housing.
5. The method of making char as claimed in claim 1, further
comprising the step of: reducing the cross sectional area of the
portion of the pyrolyzer furnace housing through which the
coal-bearing material moves in the direction of movement of the
coal-bearing material through the housing to compress the
coal-bearing materials as it moves through the pyrolyzer furnace
housing to compact the char before exiting the pyrolyzer furnace
housing.
6. The method of making char as claimed in claim 1, the step
involve heating the volatile materials in the coal-bearing material
and coal in the coal bearing material to a temperature within a
range of approximately 650.degree. F. to 1300.degree. F.
7. The method of making char as claimed in claim 1, further
comprising the step of: raising an end of the pyrolyzer furnace
housing to provide an elevation in the direction of travel of the
coal-bearing material through the pyrolyzer furnace housing.
8. The method of making char as claimed in claim 1, where step a.
involves: assembling at least three drive screws laterally
positioned within the pyrolyzer furnace housing, with each screw
being positioned such that each drive screw interleaves at least
one other screw.
9. The method of making char as claimed in claim 1, where the step
of assembling pyrolyzer furnace housing includes forming at least
two zones along its length, where the first zone is capable of
fluidizing volatile materials, and the second zone is capable of
mixing supplemental materials into the coal-bearing materials, and
plasticizing coal in the coal-bearing material in the second or
subsequent zone.
10. The method of making char as claimed in claim 1, where the step
of assembling the pyrolyzer furnace housing includes forming at
least two zones along its length, where the first zone is capable
of fluidizing volatile materials, and at least one of the
subsequent zones are capable of plasticizing coal in the
coal-bearing material.
11. A method of making char comprising the steps of: a. assembling
a longitudinal pyrolyzer furnace housing having at least two
rotatable drive screws laterally positioned and interleaved within
the longitudinal furnace housing, and capable of conveying
coal-bearing materials containing volatile material through the
pyrolyzer furnace housing, each drive screw having a hollow drive
shaft and a diverter longitudinally positioned within the drive
shaft, the diverter forming with an inner surface of each drive
shaft an inner passageway to direct heat flux from combustion fluid
moving through the inner passageway to adjacent the coal-bearing
materials moving through the pyrolyzer furnace to fluidize the
volatile material in the coal bearing material and plasticize coal
in the coal-bearing material, and having double outer walls in the
furnace housing at least partially around the rotatable drive
screws and forming an outer passageway between the outer walls, the
outer passageway capable of conveying a flow of combustion fluid
adjacent the coal-bearing materials through the pyrolyzer furnace
housing to fluidize the volatile material therein; b. assembling
combustion chambers adjacent the longitudinal pyrolyzer furnace
housing capable of burning fluidized volatile material and, if
desired, other hydrocarbon fuels, and conveying combustion fluids
through the inner passageway within the hollow drive shaft of the
rotatable drive screws and the outer passageway in the pyrolyzer
furnace housing to provide heat flux to fluidize the volatile
material in the coal bearing material and plasticize coal in the
coal-bearing material; and c. rotating the drive screws to cause
coal-bearing material containing volatile materials to move through
the longitudinal pyrolyzer furnace housing and be heated to a
temperature to fluidize volatile materials in the coal bearing
material and plasticize coal in the coal-bearing material.
12. The method of making char as claimed in claim 11, where the
flow of combustion fluid through the inner passageways and outer
passageways in the furnace housing are in the same direction as the
movement of the coal-bearing materials through the pyrolyzer
furnace housing.
13. The method of making char as claimed in claim 11, further
comprising the step of: providing a turbulent flow of combustion
fluids through the inner passageway and the outer passageway having
a Reynolds Number greater than 4000.
14. The method of making char as claimed in claim 11, further
comprising the step of: tapering outer walls of the hollow shafts
of the drive screws downstream to cause the coal-bearing material
to be compressed as it moves through the pyrolyzer furnace housing
to compact the char before exiting the pyrolyzer furnace
housing.
15. The method of making char as claimed in claim 11, further
comprising the step of: reducing the cross sectional area of the
portion of the pyrolyzer furnace housing through which the
coal-bearing material moves in the direction of movement of the
coal-bearing material through the housing to compress the
coal-bearing materials as it moves through the pyrolyzer furnace
housing to compact the char before exiting the pyrolyzer furnace
housing.
16. The method of making char as claimed in claim 11, the steps
involve heating the volatile materials in the coal-bearing material
and coal in the coal bearing material to a temperature within a
range of approximately 650.degree. F. to 1300.degree. F.
17. The method of making char as claimed in claim 11, further
comprising the step of: raising an end of the pyrolyzer furnace
housing to provide an elevation in the direction of travel of the
coal-bearing material through the pyrolyzer furnace housing.
18. The method of making char as claimed in claim 11, where step a.
involves: assembling at least three drive screws laterally
positioned within the pyrolyzer furnace housing, with each screw
being positioned to overlap with at least one other screw.
19. The method of making char as claimed in claim 11, where the
step of assembling pyrolyzer furnace housing include forming at
least two zones along its length, where the heat flux is capable of
fluidizing volatile materials in the first zone, and the second
zone is capable of mixing supplemental materials into the
coal-bearing materials, and the heat flux is capable of
plasticizing coal in the coal-bearing material in the second and/or
subsequent zones.
20. The method of making char as claimed in claim 11, where the
step of assembling the pyrolyzer furnace housing includes forming
at least two zones along its length, where the heat flux is capable
of fluidizing volatile materials in the first zone, and the heat
flux are capable of plasticizing coal in the coal-bearing material
in at least one of the subsequent zones.
Description
[0001] This application is a divisional of U.S. patent application
Ser. No. 13/608,703, filed Sep. 10, 2012, which is a
Continuation-in-Part of U.S. application Ser. No. 11/959,581, filed
Dec. 19, 2007, which claims the benefit of U.S. Provisional Patent
Application No. 60/871,863, filed Dec. 26, 2006, each of which is
incorporated herein by reference in its entirety.
BACKGROUND AND SUMMARY OF THE DISCLOSURE
[0002] The present invention relates to processing methods and
apparatus for converting coal or other coal-bearing materials into
char. Char can be produced by heating coal or other coal-bearing
materials to selected temperatures in a reduced-oxygen environment.
Char having suitable properties may be used in, among other things,
iron and steel processing furnaces.
[0003] Heating coal or other coal-bearing materials in a
reduced-oxygen environment produces coal gas, volatile liquids and
a residue of char. During the process of making char, volatile
materials, such as hydrocarbon fuels, in the coal-bearing materials
fluidize when heated to a temperature of approximately 650.degree.
F. (approximately 350.degree. C.) and higher.
[0004] A pyrolyzer furnace is one apparatus that may be used for
processing coal and other hydrocarbon materials into char. A
pyrolyzer can operate in a batch or in a continuous process. In one
continuous pyrolyzer, one or more drive screws rotate within the
pyrolyzer furnace, wherein the coal is heated in a reduced-oxygen
environment to a temperature to fluidize the volatile material as
the coal-bearing materials are moved through the furnace. An
example of a continuous pyrolyzer furnace is disclosed in U.S. Pat.
No. 5,151,159 to Wolfe, et al. Previous pyrolyzer furnaces
disclosed by the prior art had heating elements positioned within
the furnace housing, which generated hot spots within the furnace,
caused uneven heating of the coal or other coal-bearing material,
and caused fatigue and shortened the life of the furnace
components.
[0005] Another limitation has been the energy efficiency of
previous pyrolyzer furnaces. The previous pyrolyzer furnaces were
typically heated by electric heaters, or by burning natural gas,
fuel oil or propane, to process the fluidized volatile material
into hydrocarbon fuel and coal tar products. Pyrolyzer furnaces in
the prior art also had drive screws with solid shafts, oil cooled
shafts, and other shaft configurations that were thermally
inefficient, resulting in the pyrolyzer furnace consuming more
fuel.
[0006] What has been needed is a pyrolyzer furnace system, and
method for making char in that system, that substantially reduces
the external energy, e.g. propane, fuel oil, or natural gas, needed
for the char making process. The level of additional energy may be
reduced to a point that the char making process is sustained by
burning only the fluidized volatile materials generated from char
making after start up.
[0007] Disclosed is a char making apparatus comprising: [0008] a
longitudinal pyrolyzer furnace housing wherein coal-bearing
maternal containing volatile materials may be heated to a
temperature to fluidize volatile materials therein and plasticize
coal in the coal-bearing material; [0009] at least two rotatable
drive screws laterally positioned and interleaved within the
longitudinal furnace housing and capable of conveying coal-bearing
materials containing volatile material through the pyrolyzer
furnace housing, each drive screw having a hollow drive shaft and a
diverter longitudinally positioned within the drive shaft, the
diverter forming with an inner surface of each drive shaft an inner
passageway to provide heat flux from the combustion fluid moving
through the shaft to adjacent coal-bearing materials moving through
the pyrolyzer furnace to enable fluidizing the volatile material
therein and plasticizing coal in the coal bearing material; [0010]
a heating jacket about the longitudinal furnace housing along at
least a portion thereof in fluid communication with combustion
fluid from multiple combustion chambers to provide heat flux from
the combustion fluid moving through the heating jacket to heat
adjacent coal-bearing materials moving through the pyrolyzer
furnace to fluidize the volatile material in the coal bearing
material and plasticize the coal in the coal bearing material;
[0011] multiple combustion chambers adjacent the inner housing and
adjacent the heating jacket capable of burning fluidized combustion
material and exhausting combustion fluids through the inner
passageway and through the heating jacket to fluidized volatile
material in the coal-bearing material and plasticizing coal in the
coal-bearing material; and [0012] conduit capable of collecting and
transferring fluidized volatile material exhausted from the
pyrolyzer furnace to the combustion chambers to be burned.
[0013] The flow of combustion fluids through the inner passageways
within the hollow drive screws may be in the same direction as the
drive screws move the coal-bearing materials through the pyrolyzer
furnace housing.
[0014] Also, the combustion chambers are spaced along the pyrolyzer
furnace housing to distribute the combustion fluid moving from such
combustion chambers through the heating jacket to exhaust ports
from pyrolyzer furnace housing to provide a desired pattern of heat
flux from the combustion fluid to the adjacent coal-bearing
material moving through the pyrolyzer furnace housing.
[0015] Flow controllers may be positioned in the heating jacket and
are capable of diverting the flow of combustion fluid through said
heating jacket to provide a desired heat flux pattern to fluidize
volatile material in the coal bearing material and plasticize coal
in the coal bearing material.
[0016] Devices may also be positioned in the inner passageways and
are capable of causing the flow of heated fluid through the
passageway to have a Reynolds Number greater than 4000.
[0017] The portion of the pyrolyzer furnace housing downstream
through which the coal bearing material moves may have a decreasing
cross sectional area in the direction of travel of the coal-bearing
material through the pyrolyzer furnace housing to compact the char
before exiting the pyrolyzer furnace housing. Or, the pyrolyzer
furnace housing may have a tapered outer wall downstream forming a
decreasing cross-sectional area of the portion of the pyrolyzer
furnace housing through which the coal-bearing material moves in
the direction of travel of the coal bearing material through the
pyrolyzer furnace housing to compact the char before exiting the
pyrolyzer furnace housing.
[0018] The hollow drive shaft through each screw may be tapered;
decreasing the cross sectional area of the portion of the pyrolyzer
furnace housing through which the coal-bearing material moves in
the direction of travel of the coal-bearing material through the
pyrolyzer furnace housing to compact the char before exiting the
pyrolyzer furnace housing.
[0019] Alternatively, the pyrolyzer furnace housing may have
tapered inner walls and the hollow drive shafts of the drive screws
may have tapered outer walls coordinated to decrease the cross
sectional area of the portion of the pyrolyzer furnace housing
through which the coal-bearing material moves in the direction of
travel of the coal-bearing material through the pyrolyzer furnace
to compact the char before exiting the pyrolyzer furnace
housing.
[0020] The heating jacket may surround at least a portion of the
pyrolyzer furnace housing, and may surround the pyrolyzer furnace
housing substantially along its length.
[0021] The char making apparatus may also be capable of fluidizing
volatile materials and plasticizing coal in the coal-bearing
material to a temperature in a range of 650.degree. F. to
1300.degree. F.
[0022] Alternatively the pyrolyzer furnace housing may be inclined
at a variable upward angle in the direction of movement of the
coal-bearing material through the housing.
[0023] At least three drive screws may be laterally positioned
within the pyrolyzer furnace housing, the drive screws being
positioned such that each drive screw interleaves at least one
other drive screw. Further, at least one clearing screw having a
smaller diameter may be positioned longitudinally through the
furnace housing adjacent the drive screws and may be capable of
conveying coal-bearing materials from the drive screws through the
pyrolyzer furnace housing.
[0024] At least one clearing screw having a smaller diameter may be
positioned longitudinally through the furnace housing adjacent the
drive screws and capable of conveying coal-bearing materials from
the drive screws through the pyrolyzer furnace housing.
[0025] Alternatively, the pyrolyzer furnace housing may comprise at
least two zones along its length, where the heat flux in the first
zone is capable of fluidizing volatile materials, and the second
zone is capable of mixing supplemental materials into the
coal-bearing materials, and the heat flux in the second and/or
subsequent zones is capable of plasticizing coal in the
coal-bearing material.
[0026] Also, the pyrolyzer furnace housing may comprise at least
two zones along its length, where heat flux in the first zone is
capable of fluidizing volatile materials, and heat flux in at least
one of the subsequent zones are capable of plasticizing coal in the
coal-bearing material.
[0027] Another char making apparatus is disclosed, comprising:
[0028] a longitudinal pyrolyzer furnace housing wherein
coal-bearing material containing volatile materials may be heated
to a temperature to fluidize volatile materials therein and
plasticize coal in the coal bearing material; [0029] at least two
rotatable drive screws laterally positioned and interleaved within
the longitudinal furnace housing, and capable of conveying
coal-bearing materials containing volatile materials through the
pyrolyzer furnace housing, each drive screw having a hollow drive
shaft and a diverter longitudinally positioned within the drive
shaft, the diverter forming with an inner surface of each drive
shaft an inner passageway adjacent the coal-bearing materials
moving through the pyrolyzer furnace to provide heat flux from the
combustion fluid to the coal-bearing material to fluidize the
volatile material therein and plasticize coal in the coal bearing
material; [0030] double outer walls in the furnace housing at least
partially around the rotatable drive screws and forming an outer
passageway between the outer walls, the outer passageway capable of
moving a combustion fluid adjacent the coal-bearing materials
moving through the pyrolyzer furnace housing providing heat flux
from the combustion fluid moving through the outer passageways to
the coal-bearing material moving through the pyrolyzer furnace
housing to fluidize the volatile material in the coal-bearing
material and plasticize coal in the coal-bearing material; multiple
combustion chambers adjacent the inner passageway and adjacent the
outer passageway capable of burning fluidized combustion material
and moving combustion fluids through the inner passageway and the
outer passageway to fluidized volatile material in the coal-bearing
material and plasticizing coal in the coal-bearing material; and
[0031] conduit capable of collecting and transferring fluidized
volatile material exhausted from the pyrolyzer furnace to the
combustion chambers to be burned.
[0032] Also disclosed is a method for making briquettes comprising
the steps of assembling a longitudinal pyrolyzer furnace housing
having at least two rotatable drive screws laterally positioned and
interleaved within a longitudinal furnace housing and a heating
jacket about the longitudinal furnace housing to provide heat flux
from combustion fluid moving through the heating jacket to adjacent
coal-bearing materials; moving coal-bearing materials through the
pyrolyzer furnace by rotation of the drive screws and heating to
fluidize volatile material in the coal bearing material and
plasticize the coal in the coal bearing material to form processed
char; mixing the processed char with a binding agent and a binder
coal of a fluidity at least 2,000 ddpm to form a blend of less than
15% binding agent, 25 to 70% processed char and 20 to 70% binder
coal; and briquetting the blend to form a briquetted blend that can
be carbonized to form metallurgical coke.
[0033] Also disclosed is a system for making briquettes comprising
a longitudinal pyrolyzer furnace housing having at least two
rotatable drive screws laterally positioned and interleaved within
the longitudinal furnace housing, and capable of conveying
coal-bearing materials containing volatile material through the
pyrolyzer furnace housing and a heating jacket about the
longitudinal furnace housing along at least a portion thereof in
fluid communication with combustion fluid from multiple combustion
chambers to provide heat flux from combustion fluid moving through
the heating jacket to adjacent coal-bearing materials moving
through the pyrolyzer furnace to fluidize the volatile material in
the coal bearing material and plasticize the coal in the coal
bearing material to produce processed char; a mixer for combining a
binder coal having a fluidity of at least 2,000 ddpm, a binder and
said processed char in a preferred ratio to form a blend having:
less than 15% binding agent, 25 to 70% processed char, and 20 to
70% binder coal; and a briquetter for forming the blend to form a
briquette which when carbonized forms a metallurgical coke.
BRIEF DESCRIPTION OF THE DRAWINGS
[0034] FIG. 1 is a system for making char;
[0035] FIG. 2 is a second embodiment of a system for making
char;
[0036] FIG. 3 is a cross sectional view through a pyrolyzer of the
present disclosure through the section marked 3-3 in FIG. 1 or FIG.
2;
[0037] FIG. 4 is a cross sectional view through the pyrolyzer of
FIG. 3 through the section marked 4-4 in FIG. 3;
[0038] FIG. 5 is a cross sectional view through an alternate
embodiment including a double wall pyrolyzer of the present
disclosure through the section marked 3-3 in FIG. 1 or FIG. 2;
[0039] FIG. 6 is a cross sectional view through the pyrolyzer of
FIG. 5 through the section marked 6-6 in FIG. 5;
[0040] FIG. 7 is a cross sectional view through a third embodiment
of a double wall pyrolyzer of the present disclosure through the
section marked 3-3 in FIG. 1 or FIG. 2;
[0041] FIG. 8 is a cross sectional view through the pyrolyzer of
FIG. 7 through the section marked 8-8 in FIG. 7;
[0042] FIG. 9 is a cross sectional view through a fourth embodiment
of a pyrolyzer furnace of the present disclosure;
[0043] FIG. 10 is a cross sectional view through a fifth embodiment
of a pyrolyzing furnace with three screws through the section
marked 3-3 in FIG. 1 or FIG. 2;
[0044] FIG. 11 is a longitudinal cross sectional view through a
sixth embodiment of a compacting pyrolyzer of the present
disclosure;
[0045] FIG. 12 is a longitudinal cross sectional view through a
seventh embodiment of a compacting pyrolyzer of the present
disclosure;
[0046] FIG. 13 is a longitudinal cross sectional view through an
eighth embodiment of a compacting pyrolyzer of the present
disclosure;
[0047] FIG. 14 is a longitudinal cross sectional view through a
ninth embodiment of a rotatable pyrolyzer of the present
disclosure;
[0048] FIG. 15 is a longitudinal cross sectional view through a
tenth embodiment of a rotatable pyrolyzer of the present
disclosure;
[0049] FIG. 16 is a longitudinal cross sectional view through an
eleventh embodiment of a pyrolyzer of the present disclosure with
mixing capability;
[0050] FIGS. 17A and 17B are partial cross sections illustrating
two alternate screw flight designs for the pyrolyzer of the present
disclosure;
[0051] FIG. 18 is a longitudinal cross sectional view through a
twelfth embodiment of a pyrolyzer of the present disclosure with
mixing capability and combustion chambers;
[0052] FIGS. 19A-C are partial cross-sectional views illustrating
alternate arrangements of a heating jacket; and
[0053] FIG. 20 is a longitudinal cross sectional view through a
thirteenth embodiment of a pyrolyzer of the present disclosure with
mixing capability, combustion chambers, and heating zones.
[0054] FIG. 21 is a graph illustrating CSR vs. CRI for various
tested samples.
[0055] FIG. 22 is a perspective view of a briquetting system
according to one aspect of the invention.
DETAILED DESCRIPTION OF THE DISCLOSURE
[0056] As used herein, the term "coal" refers to mined carbonaceous
material containing organic compounds and volatile materials that
may be converted to a plastic phase at elevated temperatures where
carbonaceous material is separated from the volatile materials. One
example of this type of coal is bituminous coal.
[0057] As further used herein, the term "fluidize" means release of
volatile material from coal with heating during a process where
gases and entrained particulate matter, which may or may not be
combined with other gases, are released.
[0058] Referring now to FIG. 1, a furnace apparatus 10 is provided
for making char. The furnace apparatus 10 receives, as raw
materials, coal-bearing material having a predetermined size and
processes the coal-bearing material into an atmosphere containing
little, if any, oxygen. In the furnace, the coal-bearing material
is dried and then heated to a temperature to fluidize the volatile
materials in the coal and coal-bearing material and plasticize coal
in the coal-bearing material.
[0059] The furnace apparatus 10 comprises a receiving hopper 12 for
containing coal-bearing materials 14 containing coal particles of a
predetermined size. The size of the coal particles 14 may be, for
example, in a range of about 1/4 inch to about -6 Tyler mesh (about
6.4 mm to about 3.3 mm). The coal-bearing material 14 pass from the
receiving hopper 12 through an airlock 16 and into a pre-dryer 18.
The coal-bearing material 14 may less than 20 mesh or so prevalent
as effluent from coal washing facilities and in reclaiming coal
from settlement ponds created from past coal washing facility
operations. These small coal particles are readily available in
this coal-bearing material, but generally are not used because they
are difficult to transport and use.
[0060] The pre-dryer 18 comprises a drying chamber 20 within a
drying furnace 22 having a plurality of burners 24 mounted therein.
The drying chamber 20 has a drive screw 26 rotatably mounted
therein for conveying the coal particles 14 or other coal-bearing
material, through the drying chamber 20. The temperature in the
drying chamber 20 may be maintained at about 400.degree. F.
(approximately 200.degree. C.) to release at least a portion of the
water vapor incorporated within the coal-bearing material 14. A
portion of the volatile materials 28 in some coal and coal-bearing
material may begin to volatilize in the pre-dryer at about
400.degree. F. (approximately 200.degree. C.). The pre-dryer 18 may
be maintained at a temperature of about 300.degree. F.
(approximately 150.degree. C.) or lower to remove water vapor while
fluidizing little or no volatile materials 28.
[0061] The pyrolyzer furnace 30, or retort furnace, may be
hermetically connected to the pre-dryer 18 and receive the
processed coal-bearing material 14 from the pre-dryer by way of an
airlock and screw feeder 32. Two drive screws 34 are laterally
positioned adjacent each other in an overlapping array within a
longitudinal furnace housing 31 of pyrolyzer furnace 30. Each drive
screw 34 is rotatably mounted interleaved within the pyrolyzer
furnace housing 31 to move the coal-bearing material therethrough.
An electric or pneumatic motor 36 may be provided to drive the
drive screws 34 through a drive train (not shown).
[0062] In one embodiment, the coal-bearing materials passing
through the pyrolyzer furnace 30 are heated by hot combustion
fluids. In the embodiment of FIG. 1, a combustion chamber 42
comprises a blower 44 and a plurality of burners 46 designed to
combust fluidized volatile materials or other fuel at temperatures
at which volatile material in coal-bearing material will fluidize
and coal in the coal bearing material will plasticize. A conduit 48
transfers combusted fluids from the combustion chamber 42 to the
pyrolyzer furnace 30. The combustion chamber 42 is capable of
burning fluidized volatile materials 28 and/or other hydrocarbon
fuels (e.g. propane, natural gas, or fuel oil), and transferring
the combustion fluids to the pyrolyzer furnace 30 by the blower 44
through the conduit 48.
[0063] As shown in FIG. 1, the hot combustion fluids flow through
the pyrolyzer furnace 30 and then into a dryer conduit 50. The hot
combustion fluids from the combustion chamber may enter the
pyrolyzer furnace 30 through conduit 48 at a temperature of about
1600 to 1700.degree. F. (about 870 to 930.degree. C.), and may
leave the pyrolyzer furnace 30 through dryer conduit 50 at a
temperature of about 400 to 500.degree. F. (about 200 to
260.degree. C.). The combustion fluids move through the dryer
conduit 50 to the pre-dryer 18. The combustion fluids may pass
through the pre-dryer 18 to dry and preheat the coal-bearing
material, and may be exhausted at a temperature of about
100.degree. F. (about 38.degree. C.). If desired, a scrubber 56 may
receive the exhausted fluids from the pre-dryer 18 to further
separate sulfur and other impurities before being emitted to the
ambient environment.
[0064] The pyrolyzer furnace 30 is heated to a temperature to
fluidize and release the volatile materials 28 and water vapor
contained within the coal of the coal-bearing material 14,
including hydrocarbon fuels. The fluidized volatile materials 28
may comprise hydrogen and methane. Suitable piping or other conduit
are provided to transfer the fluidized volatile materials 28 from
the pyrolyzer furnace 30 to the combustion chamber 42, and the
pre-dryer 18, if desired, to fuel burners 46 in the combustion
chamber 42 and the burners 24 in pre-dryer 18.
[0065] As shown in FIG. 1, a condenser 54 may be optionally
provided in communication with the pyrolyzer furnace 30 to separate
liquids from the fluidized volatile materials 28. If desired, the
condenser 54 may be used to separate coal tar liquids 55 and water
from gaseous coal fluids using known methods and apparatus. Coal
tar liquids may be collected for sale as a commodity, or may be
transferred to the combustion chambers 24 in the pre-dryer 18 and
the burners 46 in the combustion chamber 42 to be burned as fuel.
However, in view of environmental and efficiency concerns, the char
making apparatus 10 is best operated with internal recovery where
the fluidized volatile material is transferred to the combustion
chamber 42, or the pre-dryer 18, to be combusted to provide
combustion fluids for transfer to the pyrolyzer 30.
[0066] The longitudinal furnace housing 31 of the pyrolyzer furnace
30 houses a portion where coal in coal-bearing material 14
containing volatile materials may be heated to a temperature to
fluidize volatile materials therein and plasticize coal in the
coal-bearing material. The drive screws 34 are rotatably positioned
within and along the length of the longitudinal furnace housing 31.
The drive screws 34 are rotated to move coal-bearing material
through the furnace housing 31 and discharge devolatilized and
plasticized coal residue, char 40, from the pyrolyzer furnace 30.
Char 40 from the pyrolyzer furnace 30 may be transferred to a char
cooler 58, which may be hermetically connected to the pyrolyzer
furnace 30 by way of an airlock and screw feeder 59. In one
embodiment, the char cooler 58 cools the char 40 to a temperature
below that which the char would ignite if exposed to ambient
air.
[0067] In the embodiment of FIG. 1, the exhausting combustion
fluids flow through the inner passageways 68 (FIG. 3) of drive
shafts 34 in the direction of the coal or coal-bearing material
moving through the pyrolyzer furnace housing 31. In the embodiment
of FIG. 2, the exhausting combustion fluids flow through the inner
passageways 68 of the drive shafts 34 opposite, counter-current the
direction of the coal-bearing material moving through the pyrolyzer
furnace 30.
[0068] More details of the pyrolyzer furnace 30 of the first and
second embodiments of FIGS. 1 and 2 is shown in FIGS. 3 and 4 and
taken along line 3-3 in FIGS. 1 and 2. The pyrolyzer furnace of
FIG. 3 comprises the longitudinal furnace housing 31 at least
partially covered by an insulating layer 60. At least two drive
screws 34 are laterally positioned, adjacent and overlapping,
capable of moving coal-bearing material 14 containing volatile
materials 28 through the pyrolyzer furnace 30. The two drive screws
34 are rotatably mounted in the pyrolyzer furnace housing 31 and
are driven by a conventional drive (not shown).
[0069] The pyrolyzer furnace housing 31 may be shaped to provide a
volume above the drive screws 34, as illustrated in FIG. 3. The
volume above the screws 34 provides a space for coal particles in
the coal-bearing material 14 to expand above the drive screws 34 as
the coal increases in temperature as it is moved through the
pyrolyzer furnace 30. It is contemplated that some embodiments may
provide more or less volume above the screws 34 depending on the
thermal expansion or swelling properties of the particular coal in
the coal-bearing material 14 that is processed through the
pyrolyzer furnace 30. Typically the coal in the coal-bearing
material is a bituminous coal.
[0070] As shown in FIGS. 1 and 2, each drive screw 34 comprises a
hollow drive shaft 62 (FIG. 3) in communication with the combustion
chamber 42. The conduit 48 may connect the combustion chamber 42
with the drive shafts 62. The combustion chamber 42 is capable of
burning fluidized volatile materials 28 and, if desired, other
hydrocarbon fuels, and conveying heated combustion fluids from the
combustion chamber 42 through the conduit 48 into the hollow drive
shafts and directed and restricted by inner passageways 68 within
the hollow drive shafts 62.
[0071] As shown in FIGS. 3 and 4, a diverter 64 is longitudinally
positioned within the hollow drive shafts 62. Each diverter 64
comprises an outer surface 66 forming with an inner surface of the
drive shaft 62 an inner passageway 68 capable of directing heat
flux from heated combustion fluid to adjacent the coal-bearing
materials moving through the pyrolyzer furnace 30, to fluidize the
volatile material therein and plasticizing coal in the coal-bearing
material. In one embodiment, blower 44 moves the exhausted
combustion fluids from the combustion chamber 42 through the
conduit 48 and into the inner passageways 68 of drive shafts 62 for
heating the coal-bearing material moving through the pyrolyzer
furnace 30.
[0072] As illustrated in FIG. 3, diverter 64 may be centered within
each hollow drive shaft 62 by a plurality of ribs 69 extending
radially from the outer surface 66. The ribs 69 may extend along
the lengths of the diverter 64. Alternately, a plurality of small
ribs 69 may hold the diverter in place. In one embodiment, the ribs
69 have an airfoil shape. In another embodiment, the ribs 69 are
shaped and positioned to disrupt the flow of fluid through the
inner passageway 68 for creating turbulent flow. The ends of the
diverter 64 may be tapered as illustrated in FIG. 4. Alternately,
the ends of the diverter 64 may be flat, spherical, or any other
shape suitable for directing flow of combustion fluid into and
through the inner passageways 68.
[0073] In one embodiment, the outer surface 66 of the diverter 64
comprises an approximately cylindrical shape. It is contemplated
that the outer surface 66 may comprise a corrugated shape or other
shape for forming inner passageways 68 having various shapes and
desired fluid flow through inner passageways 68. In one embodiment,
the outer surface 66 comprises a surface corrugated to direct flow
in a spiral around the diverter 64. The outer surface 66 of the
diverter 64 may comprise fluid agitators or other devices for
causing a turbulent flow in the inner passageway 68. It is
contemplated that the agitators or other devices may be
protrusions, tabs, ribs, or other shapes suitable for causing
turbulent flow in the inner passageway 68. It is contemplated that
the location, size, and shape of the inner passageways 68 may be
varied to generate a turbulent flow having a Reynolds Number
greater than 4000. In any case, the heat flux is efficiently
transferred from the combustion fluid to the coal-bearing material
moving through the pyrolyzer 30.
[0074] In one embodiment, the pyrolyzer furnace 30 heats the
coal-bearing material 14 to a temperature within a range of
approximately 650.degree. F. to 1300.degree. F. (approximately
340.degree. C. to 700.degree. C.) to fluidize volatile materials 28
within the coal-bearing material 14 and plasticize coal in the
coal-bearing material 14. In an alternate embodiment, the pyrolyzer
furnace 30 heats the coal-bearing material 14 containing volatile
materials 28 to a temperature to about 1700.degree. F. (about
930.degree. C.) or higher. As different volatile materials fluidize
and different coals plasticize at different temperatures, it is
contemplated that the pyrolyzer furnace 30 may heat the
coal-bearing material to a selected temperature for fluidizing the
volatile materials within the coal-bearing material and another
selected temperature to plasticize coal in the coal-bearing
material.
[0075] The insulating layer 60 may be a ceramic or other high
temperature insulative material. It is contemplated that the
insulating layer 60 may be a fabricated structure, a wrapped
insulation blanket, a sprayed-on insulative material, or any other
insulative or composite material around the pyrolyzer furnace
30.
[0076] In the embodiment of FIGS. 1 and 2, the drive screw 26 of
pre-dryer 18 comprises a hollow drive shaft 27 in communication
with the dryer conduit 50. In one embodiment, the pre-dryer drive
shaft 27 further comprises a diverter to form an inner passageway
between the diverter and an inner surface of the drive shaft 27,
capable of diverting heated fluid adjacent the coal-bearing
material moving through the pre-dryer 18. Alternately, the drive
shaft 27 may be capable of receiving oil, and the dryer conduit 50
is in communication with an oil heater for heating the oil flowing
through the drive shaft 27. In one embodiment, the drive shaft 27
is a Holo-Flite.RTM. screw capable of receiving oil heated by the
hot combustion fluids from the dryer conduit 50.
[0077] In an alternate pyrolyzer embodiment shown in FIGS. 5 and 6,
the pyrolyzer furnace 30 comprises double outer walls 31A forming
an outer passageway 70 or heating jacket in the pyrolyzer furnace
housing 31 at least partially around the drive screws 34. The outer
passageway 70 formed between the outer walls 31, 31A is capable of
conveying a flow of heated combustion fluid adjacent to the
coal-bearing material moving through the pyrolyzer furnace to
fluidize the volatile material therein and plasticize coal in the
coal-bearing material. The heating jacket of the pyrolyzer furnace
30 in this embodiment is at least partially covered by the
insulating layer 60. In the embodiment of FIGS. 5 and 6, the
pyrolyzer furnace housing 31 comprises the partial double outer
wall 31A, such that the outer passageway 70 surrounds a portion of
the pyrolyzer furnace. Alternately, as in the embodiment of FIGS. 7
and 8, the double outer wall 31A forming the heating jacket of the
pyrolyzer furnace housing 31, such that the outer passageway 70
surrounds the pyrolyzer furnace 30.
[0078] In this embodiment, a conduit, such as the conduit 48,
connects the outer passageway 70 to the combustion chamber 42 for
conveying exhausted combustion fluids from the combustion chamber
42 into the outer passageway 70 heating jacket of the pyrolyzer
furnace 30. The combustion chamber 42 is capable of combusting
fluidized volatile materials 28 and/or other hydrocarbon fuels, and
exhausting combustion fluids through the outer passageway 70 for
heating the coal-bearing material and plasticizing coal in the
coal-bearing material within the pyrolyzer furnace.
[0079] In the embodiments of FIGS. 5 to 8, the blower 44 may move
the exhausted combustion fluids from the combustion chamber 42
through the conduit 48, and into the inner passageways 68 of the
drive shafts 62 and the outer passageway 70, thereby heating the
coal-bearing material moving through the pyrolyzer furnace 30. It
is contemplated that the location, size, and shape of the inner
passageways 68 and the outer passageway 70, and the ribs within,
may be varied to cause the flow of heated fluid through said
passageways to have a turbulent flow having a Reynolds Number
greater than 4000.
[0080] The outer passageway 70 may have fluid agitators or other
devices positioned between the double walls of the heating jacket
to cause a turbulent flow of heated combustion fluid therein. It is
contemplated that the agitators or other devices may be
protrusions, tabs, ribs, or other shapes suitable for causing
turbulent flow in the outer passageway 70. It is further
contemplated that the location, size, and shape of the outer
passageway 70 may be varied to cause the flow of heated fluid
through said passageway to have a turbulent flow having a Reynolds
Number greater than 4000 to improve the heat flux efficiency from
combustion fluids to the coal-bearing material to fluidize volatile
materials from the coal-bearing material and plasticize the coal in
the coal-bearing material.
[0081] As shown in FIGS. 7 and 8, optionally, one or more manifold
conduits 76 may be provided for conveying heated combustion fluid
to a selected portion of the outer passageway 70 along the
pyrolyzer furnace housing 31. The manifold conduits 76 may be in
communication with the combustion chamber 42, and capable of
transferring heated combustion fluid to selected portions of the
outer passageway 70 longitudinally along the pyrolyzer furnace
housing 31. The manifold conduits 76 may be provided to maintain a
selected temperature distribution along the pyrolyzer furnace 30 to
fluidize volatile material in the coal-bearing material and
plasticize coal in the coal-bearing material. In this embodiment,
the combustion chamber 42 may transfer through conduit 48
combustion fluids to the inner passageways 68 and the outer
passageway 70 which may then exit through the manifold conduits 76.
At least one exit conduit 78 may be provided for transferring
combustion fluid out of the outer passageway 70. The heated
combustion fluids may enter the outer passageway 70 through an
entry end of the pyrolyzing furnace housing 31, one or more
manifold conduits 76, and other any suitable location.
[0082] As shown in FIG. 9, the flow of heated combustion fluid in
the inner passageways 68 and outer passageway 70 may be opposite
the direction of movement of coal-bearing material through the
pyrolyzer furnace 30. In this embodiment, heated combustion fluid
enters the outer passageway 70 by way of one or more manifold
conduits 76, and transfers out of the outer passageway 70 by way of
one or more exit conduits 78.
[0083] In one embodiment shown in FIG. 10, the pyrolyzer furnace 30
comprises at least three screws laterally positioned adjacent and
overlapping, the drive screws 34 being positioned such that each
screw overlaps at least one other drive screw. In the embodiment of
FIG. 10, two larger drive screws 34 are provided, and one small
screw 80 is provided having a smaller diameter than adjacent drive
screws 34 and positioned longitudinally through the furnace housing
adjacent the drive screws. The small screw 80 may be capable of
conveying additional fine coal to the mix with the coal-bearing
material or clearing coal-bearing material from the drive screws 34
through the pyrolyzer furnace housing. It is contemplated that
alternate embodiments may comprise at least three drive screws 34
and two clearing screws 80 for either purpose. Alternately, four
large drive screws 34 and three small clearing screws 80 may be
provided. It is contemplated that any number of screws may be
provided to accommodate a desired capacity of coal-bearing material
to be processed. The small clearing screws 80 may flow
counter-current to the large screws 34.
[0084] In one embodiment, clearing screw 80 may comprise a hollow
drive shaft and a diverter, forming an inner passageway being in
communication with heated combustion fluids from the combustion
chamber 42, as disclosed above with reference to the larger drive
screws 34.
[0085] As shown in FIG. 11, the portion of the pyrolyzer furnace
housing through which the coal-bearing material moves may have a
decreasing cross sectional area in the direction of travel of the
coal-bearing material through the pyrolyzer furnace housing. FIG.
11 illustrates pyrolyzer furnace 130 having a tapered pyrolyzer
furnace housing 131 with a tapered outer wall forming a decreasing
cross-sectional area of the portion of the pyrolyzer furnace
housing through which the coal-bearing material moves in the
direction of travel of the coal-bearing material. In this
embodiment, the tapered pyrolyzer furnace housing 131 comprises at
least two rotatably mounted tapered drive screws 134, laterally
positioned adjacent and overlapping, and being capable of conveying
coal-bearing material containing volatile materials 28 through the
pyrolyzer furnace 130.
[0086] As shown in FIG. 11, the tapered drive screws 134 comprise a
screw flight 84 having a decreasing diameter corresponding to the
reducing cross section of the pyrolyzer furnace 130, and hollow
drive shafts 62 in communication with the combustion chamber 42.
Thus, in this embodiment, the portion 86 located between the drive
shaft 62 and the pyrolyzer furnace housing 131, through which the
coal-bearing material moves, decreases in cross sectional area
along the length of the pyrolyzer furnace.
[0087] As coal-bearing material containing volatile materials is
conveyed through the pyrolyzer of the embodiment of FIG. 11, the
coal-bearing material is plasticized and forced into the reducing
area 86 by the screw flight 84, thereby compacting the coal-bearing
material as it is conveyed through the pyrolyzer furnace and
becomes char. This compaction of the plasticized coal is
accentuated if the coal in the coal-bearing material swells as some
forms of coal do during plasticization.
[0088] In this embodiment, the diverters 64 are positioned within
the hollow drive shafts 62. The diverter 64 comprises the outer
surface 66 forming with the inner surface of the drive shaft 62 an
inner passageway 68 capable of diverting heated combustion fluid
adjacent the coal-bearing material and provides high heat flux to
coal-bearing materials moving through the pyrolyzer furnace 130 to
fluidize the volatile material therein and plasticize coal in the
coal-bearing material. In one embodiment, the blower 44 moves the
exhausted combustion fluids from the combustion chamber 42 through
the conduit 48 and into the inner passageway 68 for directing heat
flux to the coal-bearing material moving through the pyrolyzer
furnace 130.
[0089] In an alternate compacting embodiment shown in FIG. 12, the
pyrolyzer furnace 30 comprises at least two rotatable tapered drive
screws 134, laterally positioned adjacent and overlapping, capable
of conveying coal-bearing material containing volatile materials
and plasticizing coal in the coal-bearing material through the
pyrolyzer furnace 30.
[0090] In this embodiment, each tapered drive screw 134 comprises a
hollow tapered drive shaft 162 in communication with and heated by
the combustion chamber 42, and a screw flight 184 having a given
outside diameter adjacent to an inner wall of the pyrolyzer furnace
housing 31. In this embodiment, the hollow drive shafts 162 through
each drive screw has a tapered outer wall with an increasing
diameter along the length of the screw in the direction of travel
of the coal-bearing material. The tapered outer wall of the drive
shaft 162 is capable of reducing the cross-sectional area of the
portion 186 of the pyrolyzer furnace housing 31 through which the
coal-bearing material moves, located between the hollow drive shaft
162 and the pyrolyzer furnace housing 31, in the direction of
travel of the coal-bearing material through the pyrolyzer furnace
housing. Optionally, the pyrolyzer furnace 30 may comprise one or
more slots 88 to provide an area for the coal-bearing material to
expand.
[0091] As the coal-bearing material containing volatile materials
convey through the pyrolyzer of the embodiment of FIG. 12, the
coal-bearing material is forced in portion 186 through a reduced
cross-section by the screw flight 184, thereby compacting and
plasticizing the coal or coal-bearing material as it is conveyed
through the pyrolyzer furnace 30.
[0092] In this embodiment, a tapered diverter 164 is positioned
within the hollow drive shafts 162. The tapered diverter 164
comprises a reverse taper cooperating with the taper of the drive
shaft 162 to form one or more inner passageways 168 through the
drive shaft 162, capable of diverting heated combustion fluid
adjacent the coal-bearing material moving through the pyrolyzer
furnace 30 to fluidize the volatile material therein and plasticize
coal in the coal-bearing material. The blower 44 moves the
exhausted combustion fluids from the combustion chamber 42 through
the conduit 48 and into the inner passageway 168 for directing heat
flux to the coal-bearing material moving through the pyrolyzer
furnace 30.
[0093] In the embodiment of FIG. 12, optionally, the pyrolyzer
furnace housing 131 may have tapered inner walls (not shown). The
tapered inner walls may be coordinated with the tapered outer walls
of the hollow drive shafts 162 to decrease the cross sectional area
of the portion of the pyrolyzer furnace housing through which the
coal-bearing material moves in the direction of travel of the
coal-bearing material through the pyrolyzer furnace.
[0094] In another alternate compacting embodiment shown in FIG. 13,
the tapered pyrolyzer furnace 130 comprises at least two of the
drive screws 34, laterally positioned adjacent and interleaved, and
being capable of conveying coal-bearing material containing
volatile materials through the pyrolyzer furnace 130 and
plasticizing coal in the coal-bearing material. In the embodiment
of FIG. 13, the drive screws 34 comprise hollow drive shafts 62 in
communication with and heated by combustion fluid exhausted from
the combustion chamber 42. Two drive screws 34 are driven in a
direction to move the coal-bearing material through the pyrolyzer
furnace 130.
[0095] In this embodiment, the pyrolyzer furnace 130 comprises a
tapering volume above the drive screws 34. The volume above the
drive screws 34 provides a space for coal-bearing material 14,
including coal particles to expand above the drive screws 34 as the
temperature of the coal-bearing material increases and the volatile
materials are fluidized and plasticizing coal in the coal-bearing
material. In the embodiment of FIG. 13, the volume above the drive
screws has a longitudinal taper with a reducing cross sectional
area along the length of the pyrolyzer furnace housing 131 in the
direction of travel of the coal-bearing material.
[0096] Thus, in this embodiment, the portion of the pyrolyzer
furnace 130 through which the coal-bearing material moves has a
decreasing volume along the length of the pyrolyzer. As
coal-bearing material 1 containing volatile materials convey
through the pyrolyzer of this embodiment, the coal-bearing material
is forced into the reducing volume of the pyrolyzer furnace 130 by
the drive screws 34, thereby compacting and plasticizing the coal
in coal-bearing material as conveyed through the pyrolyzer.
[0097] In this embodiment, the diverter 64 is positioned within the
hollow drive shafts 62. The diverter 64 comprises the outer surface
66 forming with the inner surface of the drive shaft 62 an inner
passageway 68 through the drive shaft 62, capable of diverting and
directing heat flux from the heated combustion fluid to adjacent
the coal-bearing material moving through the pyrolyzer furnace 230,
to fluidize the volatile material therein and plasticizing coal in
the coal-bearing material. In one embodiment, the blower 44 moves
the exhausted heated combustion fluids from the combustion chamber
42 through the conduit 48 and into the inner passageways 68 of the
drive shafts 62 for heating the coal-bearing material moving
through the pyrolyzer furnace 130.
[0098] In the embodiment of FIG. 14, a pyrolyzer furnace 230 has a
rotatable outer wall at least partially covered by an insulating
layer 60. At least two drive screws 34 is laterally positioned
adjacent and overlapping, and capable of conveying coal-bearing
material containing volatile materials 28 through the pyrolyzer
furnace 230, are rotatably mounted within the pyrolyzer furnace for
conveying the coal or coal-bearing material 14, including coal
particles, through the pyrolyzer.
[0099] In the embodiment of FIG. 14, the pyrolyzer furnace 230
comprises a generally cylindrical pyrolyzer furnace housing 231,
where at least a portion of the pyrolyzer furnace housing 231 is
rotatably driven about its longitudinal axis. The end walls of the
cylindrical furnace may be fixed relative to the rotating
cylindrical portion. In this embodiment, the drive screws may be
supported by non-rotating end walls or other non-rotating portion
of the pyrolyzer furnace 230.
[0100] In this embodiment, each drive screw 34 may rotate about its
longitudinal axis, and the pyrolyzer furnace outer wall may rotate
about its longitudinal axis. The longitudinal axes of the screws
and the pyrolyzer furnace may be oriented in a fixed relationship.
At least a portion of the pyrolyzer furnace housing 231 may be
rotatable around the drive screws 34.
[0101] In the embodiment of FIG. 14, it is contemplated that the
pyrolyzer furnace 230 may comprise a double outer wall forming a
heating jacket (not shown) in the pyrolyzer furnace housing 231 at
least partially around the drive screws 34. Such a double outer
wall forms an outer passageway between the outer walls capable of
conveying a flow of heated fluid adjacent to the coal-bearing
material moving through the pyrolyzer furnace to direct heat flux
to coal-bearing material fluidize the volatile materials therein
and plasticizing coal in the coal-bearing material. In one
embodiment, heated combustion fluid may be directed into the double
wall cavity through a conduit, plenum or other channel through the
non-rotating portion of the pyrolyzer furnace 230.
[0102] As shown in FIG. 14, each drive screw 34 may comprise a
hollow drive shaft 62 in communication with the combustion chamber
42. The diverter 64 is positioned within the hollow drive shafts
62. The diverter 64 comprises the outer surface 66 forming with an
inner surface of the drive shaft 62 an inner passageway 68 capable
of diverting heated fluid adjacent the coal-bearing material moving
through the pyrolyzer furnace 230, to fluidize the volatile
material 28 therein to improve the heat flux efficiency between the
combustion fluid and the coal-bearing material to fluidize volatile
material in the coal-bearing material and plasticize coal in the
coal-bearing material. The blower 44 may move the exhausted
combustion fluids from the combustion chamber 42 through the
conduit 48 and into the inner passageways 68 for direct heat flux
to the coal or coal-bearing material moving through the pyrolyzer
furnace 230. The location, size, and shape of the inner passageways
68 may be varied to cause the flow of heated fluid through said
passageways to have a turbulent flow having a Reynolds Number
greater than 4000 to improve heat flux.
[0103] The conduit 48 connects the combustion chamber 42 with the
drive shafts 62. The combustion chamber 42 is capable of combusting
fluidized volatile materials 28 and/or other hydrocarbon fuels, and
exhausting combustion fluids through the inner passageways 68. In
one embodiment, the blower 44 moves exhausted combustion fluids
through the conduit 48 and through the inner passageways 68.
[0104] The diverter 64 may be centered within the hollow drive
shaft 62 by a plurality of ribs 69 extending along the outer
surface 66. The ribs may extend continuously the length of the
diverter. Alternately, a plurality of small ribs holds the diverter
in place. In one embodiment, the ribs 69 have an airfoil shape. If
desired, the ribs 69 may be shaped and positioned to disrupt flow
of gas through the inner passageway 68 for creating turbulent flow
to improve heat flux. The ends of the diverter 64 may be tapered.
Alternately, the ends of the diverter may be flat spherical, or any
other shape suitable for directing flow into the inner passageways
68 and improving heat flux efficiency.
[0105] As shown in FIGS. 14 and 15, the insulating layer 60 may be
a ceramic or other high temperature insulative material. The
insulating layer 60 may be a fabricated structure, a wrapped
insulation blanket, a sprayed-on insulative material, or any other
insulative or composite material around the pyrolyzer furnace
230.
[0106] In one rotatable furnace embodiment shown in FIG. 15, the
pyrolyzer furnace 230 may comprise at least three screws laterally
positioned adjacent and overlapping, the screws being positioned
such that each screw overlaps at least two other screws. Two larger
drive screws 34 are provided, and one small screw 80 is provided
having a smaller diameter than an adjacent drive screw 34. The
small screw may be a clearing screw or a drive screw. It is
contemplated that alternate embodiments (not shown) may comprise
more than two larger drive screws 34 and at least two smaller
screws 80 arranged to convey fine coal particles to coal-bearing
material within the rotatable pyrolyzer furnace 230. Alternatively,
the smaller screws may be used to clear coal-bearing material from
the drive screws as the coal in the coal-bearing swells.
[0107] In one embodiment, small screw 80 comprises a hollow drive
shaft and a diverter, the hollow drive shaft being in communication
with and heated by the combustion fluids from combustion chamber
42, as disclosed above with reference to the larger drive screws
34.
[0108] The char produced in the pyrolyzer furnace 30 may be used in
various commercial applications. In some commercial processes, the
char may be mixed with supplemental materials, such as silicon or
iron ore for use in other processes. The plasticized char may used
directly in steel making or further processed into coke for use in
a blast furnace. We have found that when the char is in a heated,
plastic state within the pyrolyzer, other materials can be added
and mixed with the plasticized char. The supplemental materials
added to the plasticized char become well-mixed in the char when
the char solidifies and cools.
[0109] In the embodiment of FIG. 16, the pyrolyzer furnace 30
comprises a first zone 90 capable of fluidizing volatile materials
and a second zone 92 capable of mixing supplemental materials such
as coal fines into the char. In the embodiment of FIG. 16, a second
zone inlet 94 may be provided for introducing supplemental
materials into the furnace housing 31. The second zone inlet 94 may
be positioned adjacent the beginning of the second zone 92. In this
embodiment, the second zone 92 begins at a location where the
coal-bearing material in the pyrolyzer furnace becomes molten and
plasticized, or at about 1/3 of the length of the pyrolyzer
furnace, and the supplemental material may be introduced into the
second zone and mixed into the char.
[0110] The pyrolyzer furnace of any of the foregoing embodiments
may heat the coal-bearing material to a temperature within a range
of approximately 650.degree. F. to 1300.degree. F. (approximately
340.degree. C. to 700.degree. C.) to fluidize the volatile
materials 28 contained in the coal or coal-bearing material and
plasticize coal in the coal-bearing material. In an alternate
embodiment, the pyrolyzer furnace 30 heats the coal-bearing
material containing volatile materials 28 to a temperature of
approximately 1700.degree. F. (approximately 930.degree. C.) or
higher. As different volatile materials fluidize at different
temperatures and different coals plasticize at different
temperatures, it is contemplated that the pyrolyzer furnace 30 may
heat the coal-bearing material to a selected temperature for
fluidizing the volatile materials within the coal-bearing material
and plasticizing coal in the coal-bearing material being
processed.
[0111] It is contemplated that the screw flights of the drive
screws in any of the foregoing embodiments may be varied to process
different coal-bearing material and at different rates. For
example, for a given screw diameter, a screw flight may have tall,
closely spaced flights as illustrated by FIG. 17A, or short, spaced
apart flights as illustrated by FIG. 17B. It is contemplated that
the screw design may be varied depending on the heat flux
properties of different coal or coal-bearing material being
processed and desired production capacity.
[0112] In any of the foregoing embodiments, it is contemplated that
the pyrolyzer may be inclined upwardly in the direction of movement
of the coal-bearing material through the pyrolyzer furnace housing.
An inclined pyrolyzer furnace may increase heat transfer by
providing more surface contact between the coal-bearing material
and the pyrolyzer. It is further contemplated that the incline
angle may be variable to accommodate processing of different types
of bituminous coal. An inclined pyrolyzer may also reduce the
amount of floor space used by the pyrolyzer.
[0113] The flow of exhausted combustion fluids through the inner
passageways 68, formed between the diverter and the inner surface
of the hollow drive shaft, may be in the same direction as the
drive screws move the coal-bearing material through the pyrolyzer
furnace housing. Alternately, the exhausting combustion fluids flow
through the inner passageways opposite the direction of the
coal-bearing material moving through the pyrolyzer furnace.
[0114] When some coal-bearing material c are heated in a pyrolyzer
to a temperature sufficient to fluidize volatile materials, the
coal or coal-bearing material transitions to a plastic stage. Some
coals in a plastic stage have high viscosity, tar-like adhesive
properties that cause the material to drag or stick to the screw
flights. In one char making apparatus, one drive screw has a
different screw pitch than an adjacent screw, and positioned such
that one screw wipes material from other screw. Also, the drive
screws 34 may be able to be reversed in rotation, or driven at
different rotational speeds, to assist in keeping the drive screws
34 free of processed coal and coal-bearing material.
[0115] It is contemplated that the pitch of a screw may change
along the length of the screw to accommodate the coal-bearing
material in a solid state at the entry end of the furnace to a
plastic state within the furnace to forming char.
[0116] Water may be introduced into any of the foregoing pyrolyzer
furnace embodiments for partial gasification of the coal in
coal-bearing material in the furnace. In one embodiment, water is
introduced into the pyrolyzer furnace where the coal in
coal-bearing material containing volatile materials reaches a
temperature to fluidize the volatile materials and plasticize coal
in the coal-bearing material. The water may react with the
fluidized volatile materials for producing carbon monoxide and
hydrogen compounds such as hydrogen gas and methane in addition to
char.
[0117] It is contemplated that the fluidized volatile materials 28
removed from the coal-bearing material may be sufficient to fuel
the burners 46 in the combustion chamber 42 without supplemental
fuel. However, it is further contemplated that some coal-bearing
material may not devolatilize a sufficient amount of volatile
material to fuel the combustion chamber 42, at least when starting
a pyrolyzer furnace campaign. The hydrogen produced from the
introduction of water may be used to additionally fuel the
combustion chamber 42.
[0118] By the pyrolyzer furnace, various carbon and
hydrocarbon-bearing products, such as municipal waste, organic
material, tires, hydrocarbon sludge, tar sand, oil shale, coal
fines and other carbon-bearing materials may be effectively
processed to heat the coal-bearing material and transfer the
coal-bearing material into char.
[0119] With reference to FIG. 18, an additional embodiment of a
pyrolyzer furnace 230 is shown. In this embodiment, coal-bearing
material 214 is delivered to the pyrolyzer furnace housing 231
through screw feeder 232 where the material 214 engages the
interleaved pair of drive screws 234 and is processed into char 240
which is delivered through an output 259 to a char cooler or the
like. During the charring process, fluidized volatile materials 228
are released from the coal-bearing material 214 to be processed in
the combustion chamber into combustion fluids. The fluidized
volatile materials 228 are removed from the pyrolyzer furnace
housing 231 through an exhaust duct 235 and transferred to a plenum
237 that collects, stores, and provides a relatively steady flow of
fluidized volatile materials 228 to a booster pump 238 that
pressurizes the coal gas 229.
[0120] Pressurized fluidized volatile material 229 from the booster
pump 238 is transferred to a manifold 241 that feeds a number of
combustion chambers 224A-D (referred to generally as 224) each
having a combustion burner (not shown). The combustion chambers 224
receive the pressurized fluidized volatile material 229 from the
manifold 241 and combust it to produce combustion fluids 243 that
flow through conduits 276 to the hollow drive shaft 262 typically
in both of the interleaved drive screws 234 and to a heating jacket
270 having insulating layer 260 round the pyrolyzer housing 231.
The combustion fluids 243 flow through the heating jacket 270 and
are exhausted through exit conduits 278 in fluid communication with
a waste gas header 279. The waste gas header 279 communicates with
a waste gas stack 281 for exhausting the combustion fluids 243 to
the atmosphere or additional treatment facility.
[0121] According to the embodiment illustrated in FIG. 18, the
pyrolyzer furnace 230 includes four combustion chambers 224,
labeled 224A-D. In this embodiment, a first burner 224A is
positioned adjacent one or both of the hollow drive shafts 262
extending through typically both of the interleaved drive screws
234. The combustion chamber 224A receives fluidized volatile
material 229 from manifold 241 and combusts it to produce heated
combustion fluid 243. This heated combustion fluid 243 is moved
through the hollow drive shafts 262 where it is diverted to the
inner passageways 268 by the diverters 264, thereby improving heat
flux to the coal-bearing material 214 moving through the
interleaved pair of drive screws 234 to heat the coal-bearing
material 214 moving through the pyrolyzer furnace housing 231.
[0122] Similarly, combustion chambers 224B-224D receive fluidized
volatile material 229 through manifold 241 and combusts the
fluidized volatile material 229 to produce heated combustion fluid
243. This heated combustion fluid 243 is moved through heating
jacket 270, thereby also heating coal-bearing material 214 moving
through the interleaved pair of drive screws 234. As shown in FIGS.
18 and 19A-D, heating jacket 270 is formed with the insulating
layer 260 and surrounds the pyrolyzer furnace housing 231. This
heating jacket 270 is in fluid communication with combustion
chambers 224B-D through manifold conduits 276. The combustion
chambers 224B-D combust fluidized volatile material 229 received
through manifold 241 and move heated combustion fluid 243 through
the manifold conduit 276 into the heating jacket 270. Flow
controllers 245 are positioned within the heating jacket (FIG. 19B)
to direct the combustion gases 243 through the heating jacket 270
in a preferred flow pattern to exhaust through exit conduits 278
positioned connected to heating jacket 270 opposite combustion
chambers 224 B-D. The combustion gases 243 exhausted through the
exit conduits 278 are in fluid communication with waste gas header
279.
[0123] In the embodiment illustrated in FIGS. 18 and 19A,
combustion fluid 243 enters the heating jacket 270 at the underside
of the pyrolyzer furnace housing 231, passes through the manifold
conduits 276 and exits the upper side of the pyrolyzer furnace
housing 231 through the exit conduits 278. As illustrated in FIG.
19B, the combustion fluid 243 may enter one or the other side of
the furnace housing 231 and exit from the opposite side of the
furnace housing 231. Alternatively, as shown in FIG. 19C, the
manifold conduit 276 and exit conduit 278 may be positioned to
provide any desired path flow pattern using flow controllers 245
directing heat flux from the combustion fluid 243 to the
coal-bearing material moving through the pyrolyzer furnace housing
231, as desired. Other arrangements and variations are contemplated
and will be apparent from the desired heat distribution through the
jacket 270 to the coal-bearing material moving through the
pyrolyzer furnace housing 231.
[0124] According to one embodiment of the system illustrated in
FIGS. 18 and 19A, the flow controllers 245 are positioned so that
combustion gas flows more evenly around the heating jacket 270 and
the heat flows through the pyrolyzer furnace housing 231 to the
coal-bearing material is symmetrical within the heating jack 270.
According to alternative embodiments, flow controllers 245 may
direct more or less combustion fluid 243 in one direction or
another, providing desired heat flux distribution about
coal-bearing material moving through the furnace housing within the
jacket 270.
[0125] In all of these embodiments, heat flux provided to the coal
or coal-bearing material 214 from the combustion fluid 243 moving
through the inner passageways 268 and the heating jacket 270 cause
the coal-bearing material 214 moving through the pyrolyzer furnace
housing 231 to fluidize volatiles in the coal-bearing material and
plasticize coal in the coal-bearing material to form char 240. The
combustion fluid 243, with heat reduced, is then exhausted from
hollow shafts 262 and heating jacket 270.
[0126] With reference to FIG. 20, another embodiment of the
improved pyrolyzer is shown. In this embodiment, the heating jacket
270 is separated by dividers 271 into separate heating zones,
Z.sub.1, Z.sub.2, and Z.sub.3. The first zone Z.sub.1 extends from
the screw feeder 232 to a first divider 271A; the second zone
Z.sub.2 from the first divider 271A to a second divider 271B; and
the third zone Z.sub.3 from the second divider to the output 259.
Each of these three heating zones may be independently controlled
by the amount of heating of combustion fluids 243 by burning
fluidized volatiles material with combustion chambers 2241, 224C,
and 224D. The heating zones are positioned to provide different
levels of heat flux to the coal-bearing material 214 as it moves
through the length of the interleaved pair of drive screws 234. The
coal-bearing material 214 may travel at different desired rates as
the coal-bearing material moves through the different zones along
the interleaved pair of drive screws 234, and thereby be exposed to
controlled heat flux levels in each of the heating zones for
predetermined amounts of time. The dividers 271 may be positioned
and insulated to inhibit heat transfer between adjacent zones and
ensure proper heat flux levels within each of the zones.
[0127] According to the illustrated embodiment, the first
combustion chamber 224B provides combustion fluid to the first zone
Z.sub.1 at a first temperature and heat flux rate to efficiently
fluidize the volatiles in the coal-bearing material. This first
temperature is selected to heat the coal-bearing material 214 to
temperature, e.g. 600-700.degree. F., to efficiently result in a
large amount of volatile materials in the coal-bearing material
being released as gas or particulate, becoming fluidized in the
atmosphere above the coal or coal-bearing material in the furnace
housing 231. These fluidized volatile materials are captured and
conveyed by duct 235 to the plenum 237.
[0128] Further according to embodiment illustrated in FIG. 20, the
second combustion chamber 224C provides heated combustion fluid to
the second zone Z.sub.2 at a second temperature and heat flux rate
to efficiently plasticize coal in the coal-bearing material 214.
This second temperature is selected to maintain the temperature of
the coal-bearing material 214 at a temperature of 650.degree. F.
and above, causing the coal or coal-bearing material to be
efficiently plasticized and further release volatile materials into
the surrounding atmosphere. The heat flux of this second zone
Z.sub.2 is selected and maintained to raise the temperature of the
coal-bearing material 214 and provide for fluidizing the volatile
materials and plasticizing coal in the coal bearing material 214.
The fluidized volatile materials are captured by the conduit duct
235 and conveyed to the plenum 237. The amount of fluidized
volatile materials released in the second zone Z.sub.2 may be
greater than that is released in the first zone Z.sub.1 of the
furnace housing 231.
[0129] As the coal in coal-bearing material 214 plasticizes at
temperature at approximately 640.degree. F. and above, the coal
becomes a high viscosity and adhesive liquid which may contain
non-plasticized components of the coal-bearing material. During
this plasticization phase, carbon from the coal forms into long
chains while hydrogen, oxygen, and contaminants are released as
gases or particulate matter. These gases and particulate matter are
fluidized into the surrounding atmosphere where they are captured
by the conduits 278 and conveyed to the plenum 237.
[0130] The plasticized carbon remaining, with most of the volatile
materials released, comprises carbon which may agglomerate to
devolatized chunks of char as they cool. According to one
embodiment, non-coal-bearing material and certain coal that does
not plasticize when heated to the plasticization temperature may
also be included with the char 240. To explain, as the plasticized
coal agglomerates, particles of the non-coal material and
non-plasticizing coal may be agglomerated into the plasticized
coal. In addition, 20 mesh coal fines may be added to the
coal-bearing material along the pyrolyzer housing and may be
agglomerated into the plasticized coal, resulting in desirable
char.
[0131] Finally, the third combustion chamber 224D provides
combustion fluid to the third zone Z.sub.3 at a third temperature.
This third temperature is selected to maintain the coal-bearing
material 214 at the plasticization temperature of approximately
650.degree. F. and above. Through this third zone, a large portion
of the coal in the coal-bearing material 214 is plasticized and
converted into char 240.
[0132] In each of the combustion chambers 224, either the
temperature or amount of combustion fluid 243 may be regulated. In
order to control the temperature of the combustion fluid 243, the
combustion chambers 224 may be supplemented as desired to mix the
combustion fluid with an outside gas or fuel sources. This mixing
may be regulated to produce a desired heat flux in each of the
zones, thereby controlling the temperature of the combustion fluid
in the heating jacket 270. Alternatively, the amount of combustion
fluid 243 provided into the heating jacket 270 in each zone may be
varied. By adjusting the rate of consumption of fluidized volatile
materials 229 by the burner 224, the amount of heat introduced into
the heating jacket 270 through the combustion gas 243 may be varied
to control fluidized volatiles in the coal-bearing and plasticize
coal in the coal-bearing material to form char 240. As the
coal-bearing material 214 draws heat from the combustion fluid, the
temperature of each zone may be controlled and fluidization of the
volatiles in the coal-bearing and plasticization of coal in the
coal-bearing material is controlled.
[0133] The embodiment illustrated in FIG. 20 has three separate and
distinct heating zones Z, each controlled by one or more separate
combustion chambers 224. This embodiment may also refine the shape
of the diverter 264 and the inner passageway 268 within the shaft
of the drive screws 234 to control the heat flux to the
coal-bearing material in each zone. Further, a separate combustion
chamber may be provided for each drive screw 234 to provide desired
temperatures and heat flux.
[0134] It is also contemplated that additional zones Z may be
provided to establish different regions with different levels of
heat flux with different temperatures in the heating jacket 270. It
is contemplated that the temperature and heat flux of each
individual combustion chamber 224 can be independently and variably
controlled.
[0135] In yet another embodiment of the present invention, the char
240 discharged from the pyrolyzer 230 may be combined with a binder
coal in order to produce briquetted metallurgical coke. A
metallurgical coke is a dense, crush-resistant fuel for use in iron
and steel making. According to a one description, metallurgical
coke is material having a CRI (Coke Reactivity Index) less than 25%
and a CSR (Coke Strength after Reaction) greater than 60%, as
defined by ASTM standard D5341-99 (Standard Test Method for
Measuring Coke Reactivity Index (CRI) and Coke Strength after
Reaction (CSR)). In an alternative description, metallurgical coke
is material having CRI and CSR relationship that falls between the
dashed lines in FIG. 21.
[0136] In the present briquetting process, a coal-bearing material
having less than 30% volatile materials is produced to char in the
pyrolyzer 230. The char 240 from the pyrolyzer 230 is mixed with a
binder coal having a mid or high fluidity as determined by ASTM
standard D2639-08 (Standard Test Method for Plastic Properties of
Coal by the Constant-Torque Gieseler Plastometer). The binder coal
is ground and mixed with the char 240 to form a blend. The blend is
then mixed with a binding agent; such as bitumen, asphalt, coal tar
pitch, or other petroleum, plant, or animal based viscoelastic
polymer; and briquetted. The briquettes are then cured by heating
and quenching, thereby producing coke briquettes suitable for
metallurgical coke.
[0137] The binder coal has a fluidity of at least 2,000 ddpm and
less than 15% volatile materials. The briquettes are comprised of
25-75% char, 15-70% binder coal, and less than 20% and generally
5-15% binding agent. The binder coal may have a fluidity of at
least 5,000 ddpm and the briquettes comprise at least 60% char, 5%
binding agent, and 30% binder coal.
[0138] In making the briquettes, coal-bearing material 214 may be
ground to, for example, 12 to 20 mesh and processed into char 240
in a twin-screw longitudinal pyrolyzer furnace 230 by the
above-described pyrolyzing process. The char 240 is delivered to a
hopper for charging to a mill as described below to be mixed with
the binder coal.
[0139] A binder coal is selected having a mid- to high-fluidity of
at least 2,000 ddpm, and may have a fluidity of 5,000-11,000 ddpm
or more. A high degree of coal fluidity is desired to provide
briquettes with a high (SR value, although lower fluidity coals may
also provide a high CSR value. Higher fluidity coals with a lower
CSR value may be selected as these coals are seen as less desirable
and therefore produce less expensive coke. The binder coal may be
ground substantially smaller than the mesh size of the char to, for
example, 50 to 70 mesh.
[0140] The ground binder coal may be mixed, for example in a
tumbler or pug mill mixer, with the char and a binding agent is
applied to form a blended material. The blend may comprise 5 to 15%
binding agent, 20 to 70% binder coal, and 25 to 70% char or may
comprise 6 to 12% binding agent, 20 to 70% binder coal and 35 to
60% char. The mix of char and binder coal will depend on the binder
coal selected, with a higher proportion of binder coal likely for
coals having a lower fluidity.
[0141] The blend is next briquetted in a compression briquetting
machine, at, for example, a pressure of 560 to 600 bar, in a
briquetting roll. These briquettes may then charged and heated in a
furnace and thereafter quenched, thereby producing briquettes
suitable for use as metallurgical coke.
EXAMPLES
[0142] In various tests of the pyrolyzer and briquetting processes,
char was produced in a twin-screw pyrolyzer and briquetted with a
binding coal and binding agent and briquetted. The briquettes were
carbonized and the strength (CSR) and reactivity (CRI) of the
formed coke briquettes were measured according to a modified ASTM
D5341-99 standard using uncrushed briquettes.
[0143] The char may be formed in the twin-screw pyrolyzer as
described above from two different sources of coal-bearing
material: Teco Myra coal (described in Appendix A) and Solar
Sources coal (described in Appendix B). Each of these coals may be
mixed with one of two different binder coals: Virginia Crews
(described in Appendix C) and Blue Creek 7 (described in Appendix
D). A binding agent, asphalt Shell HV06, was then added to the
mixture and the resultant blend was briquetted at 560 to 600 bar in
briquetting rolls. Each of the blends comprised 60% char, 30%
binder coal, and 10% binding agent.
[0144] In order to test the CSR and CRI of the briquettes, the
briquettes were carbonized in a Jenkner retort. The retort was
preheated to about 600.degree. C. at which point the briquettes
were introduced to the oven. The oven was maintained at a constant
temperature of about 600.degree. C. for 80 minutes and increased to
1020.degree. C. at a rate of 3.degree. C./h. Finally the briquettes
were maintained at 1020.degree. C. for 60 minutes, and then cooled.
The CSR and CRI of the briquettes was measured. CS0% is a
measurement representing the cold strength of the briquettes as the
fraction of pieces greater than 10 mm in size after 600 rotations
in an I-drum. The results are reproduced in the following Table
1:
TABLE-US-00001 Briquette Blend CRI % CSR % CS0 % 60% Myra Char 32.6
55.8 79.3 30% Poca 3 60% Myra Char 25.9 67.3 88.7 30% Virginia
Crews 60% Myra Char 22.9 68.2 80.2 30% Blue Creek 7 60% Myra Char
27.9 66.0 88.6 15% Virginia Crews 15% Blue Creek 7 60% High Vol.
Myra 26.0 70.3 90.3 30% Virginia Crews 60% Solar Sources 29.6 60.1
84.5 30% Virginia Crews 60% Solar Sources 33.0 53.2 80.7 30% Blue
Creek 7
[0145] A base test to determine the CSR/CRI of the coal briquettes
was performed by combining Myra char with Poca 3 binder coal. The
CSR and CRI of these briquettes were then determined. Various other
binding coals were then selected and combined with char produced
from either Tyco Myra or Solar Sources coal to form briquettes. The
CSR and CRI of these briquettes was recorded and reproduced in the
above Table 1. The CSR and CRI tests were carried out on uncrushed
briquettes rather than crushed briquettes required by the ASTM
standard, and so the comparison between various blends is made with
respect to the briquettes formed using Tyco Myra char and Poca 3
binding coal.
[0146] These briquettes were formed by crushing the char and
bitumen to <1 mm and the binder coal to <0.212 mm separately
in laboratory ball mills. 4-5 kg of each blend were prepared for
briquetting. The blends were fed directly between the rolls of a
briquetting machine operated from 560-600 bar to produce well
shaped briquettes around 40 g each. The briquettes were next
carbonized in a Jenkner retort by introducing the briquettes at
600.degree. C. and keeping them at temperature for 80 minutes. The
temperature was then increased to 1020.degree. C. at 3.degree.
C./hour and held there for 60 minutes before cooling down.
[0147] Once the briquettes had been formed and carbonized, the CSR
and CRI of each type of briquette was determined and is reproduced
in the above table. From this data, it was found that the binder
coal has an important effect on the briquette's reactivity, which
may also be dependent on the lump size. Further, higher rank coal,
such as Tyco Myra, produces better CSR results than lower rank
coals, such as Solar Sources. The volatile matter of the char has a
limited effect on the CSR and CRI compared to the effect of the
binder coal.
[0148] As evidenced by Table 1, the mid-fluidity binder coal,
Virginia Crews (2688 ddpm), produced a higher CSR than the
low-fluidity Poca 3 (65 ddpm) briquettes. The reactivity of the
briquettes was good using a mixture of high-fluidity and low
fluidity coal, further evidencing the impact of high fluidity coals
as suitable binder coal for producing metallurgical coke
briquettes. As seen by Table 1, the blend with low fluidity Poca 3
was short of producing quality metallurgical coke.
[0149] Also described in the present system and apparatus 300 to
produce metallurgical coke briquettes as illustrated in FIG. 22. In
this system, coal-bearing material 214 is provided to a pyrolyzer
furnace 230 that produces, through the above-described pyrolyzing
process, char 240. The char 240 is delivered from the pyrolyzer to
a char hopper 302. A binder coal hopper 304 holds and stores binder
coal 306 that is ground to a fine mesh, e.g. less than or equal to
60 mesh.
[0150] The binder coal 306 and char 240 are delivered from their
respective hoppers 302, 304, onto a conveyor 308 and delivered to a
crusher 310, such as a roll crusher, that provide the char 240 and
binder coal 306 of an appropriate size, which may be for example
less than or equal to 60 mesh. The mixture is next delivered to a
mixer 312, such as a pug mill mixer, that an even mix of char and
binder coal.
[0151] The mixture of binder coal 306 and char 240 is conveyed past
a tank 302 containing a binding agent 316 (asphalt), where the
mixture is sprayed with the binding agent 316 providing a blend 318
of binding agent 316, binder coal 306 and char 240. The blend 318
may comprise, for example, 10% binding agent, 30% binder coal and
60% char. The mixture may be within the range of 5 to 10% binding
agent, 20 to 70% binder coal and 25 to 75 percent char.
[0152] The blend 318 is next conveyed to a briquetter 320 to
produce briquettes. The briquetter 320 may be a roll press
briquetter that conveys the blend 318 into a briquette mold and
applies a pressure to the blend 318 in the mold to form briquettes
322. The roll presses may provide, for example, 560 to 600 bar
pressure in forming the briquettes. The formed briquettes 322 are
transferred to a briquette hopper 324 for storage.
[0153] The briquettes 322 in the hopper 324 may be conveyed through
a charging furnace 326 and subsequently quenching the briquettes
322. In an elongated charging furnace 326, the temperature of the
briquettes 322 is slowly increased to form hot briquettes, before
submerging the briquettes into a water bath to quench them. As
briquettes 322 are heated to a temperature sufficient to plasticize
the binder coal within the briquettes in the furnace 326, fluidized
coal is caused to penetrate and strengthen the char to sufficient
levels to form metallurgical coke. Further, as the briquettes 322
are heated in furnace 326, volatile materials in the binding agent
and binder coal are fluidized and released from the briquettes.
These volatile materials may be captured and utilized in the
pyrolyzer for heating the coal-bearing material as described above.
Alternatively, the volatile materials may be processed to safely be
exhausted through a stack, or captured and combusted to provide
heating to the charging furnace 326.
[0154] The above-described ranges for the char 240, binder coal 306
and binding agent 316 for the blend may be varied depending on the
particular compositions of the char 240, binder coal 306 and
binding agent 316. For example, because the binding agent 316 may
contain a large proportion of volatile materials that will be
exhausted from the briquettes during the charging to furnace 326, a
lower proportion of binding agent may be provided in the blend 318.
By using binder coals 306 having a higher level of fluidity, the
amount of binding agent 316 required to bind the briquettes may be
reduced to approximately 6 to 12%, depending on the coal
composition. Very high levels of binder coal 306 fluidity may
therefore be desired, to approximately 11,000 ddpm, reducing the
preferred level of binding agent 316 in the blend 318.
[0155] During the coal charging process the binder coal 306
plasticizes as it reaches the plasticization temperature and
penetrates pores in the char 240 to enhance the strength of the
briquettes 322. The proportion of char 240 to binder coal 306
should therefore be controlled to provide the strength (CSR) and
reactivity (CRI) of the briquettes at a desired level. The blend
may comprise 35 to 65% char 240, with the remainder being binder
coal 306 and binding agent. The proportion of char to binder coal
may be, as with the binding agent, variable depending on the
fluidity of the binder coal. A binder coal having a very high
fluidity may be used with a high proportion of char. However,
binder coals having a lower fluidity may tend to have a higher CSR,
and therefore a lower proportion of char is usually appropriate to
provide the threshold CSR values for metallurgical coke.
[0156] While the invention has been described with detailed
reference to one or more embodiments, the disclosure is to be
considered as illustrative and not restrictive. Modifications and
alterations will occur to those skilled in the art upon a reading
and understanding of this specification. It is intended to include
all such modifications and alterations in so far as they come
within the scope of the claims, or the equivalence thereof.
TABLE-US-00002 APPENDIX A Name Tyco Myra Proximate Analysis
Moisture (%) -- Ash (%/s) 8.7 Volatile Materials (%/s) 35.2
Volatile Materials (%/p) 38.55421 Fixed Carbon 56.1 Ultimate
Analysis Carbon (%/s) 78.3 Hydrogen (%/s) 5.07 Oxygene (%/s) 7
Nitrogen (%/s) 1.54 Sulfur (%/s) 0.88 Chlorine (%/s) 0.18 Coking
Properties Dilatometer Test T1 (.degree. C.) 374 T2 (.degree. C.)
415 T3 (.degree. C.) 439 Concentration (%) -25 Dilation (%) 21
General Factor (--) -- Plasticity T1 (.degree. C.) 392 T2 (.degree.
C.) 428 T3 (.degree. C.) 461 Max Fluidity 584 Maceral Analysis
(measures) Vitrinite (%) 73.3 Exinite (%) 9.9 Inertinite 8.6
Semi-Fusinite 2.6 Fusinite 0.6 Other 0 Mineral Calc. (%) 5.097 Ash
Analysis Provider (--) Socor SiO2 (%) 54.5 Al2O3 (%) 30.6 CaO (%)
1.8 MgO (%) 0.8 TiO2 (%) 1.6 Na2O (%) 0.7 K2O (%) 3.2 Fe2O3 (%) 6.1
Mn3O4 (%) 0.1 P2O5 (%) 0.2 SO3 (%) 0.5 Physical Properties
Granularity <21 mm (%) -- <19 mm (%) -- <16 mm (%) --
<10 mm (%) 100 <5 mm (%) 96.4 <3.15 mm (%) 89.5 <2 mm
(%) 75.4 <1 mm (%) 51.6 <0.5 mm (%) 32.6 <0.2 mm (%) 15.8
<0.16 mm (%) 13.1 <0.1 mm (%) --
TABLE-US-00003 APPENDIX B Name Solar Sources Proximate Analysis
Moisture (%) -- Ash (%/s) 8.6 Volatile Materials (%/s) 35.6
Volatile Materials (%/p) 38.94967 Fixed Carbon 55.8 Ultimate
Analysis Carbon (%/s) 76.7 Hydrogen (%/s) 4.61 Oxygene (%/s) 7.9
Nitrogen (%/s) 1.45 Sulfur (%/s) 0.85 Chlorine (%/s) 0.03 Coking
Properties Dilatometer Test T1 (.degree. C.) 342 T2 (.degree. C.)
409 T3 (.degree. C.) 434 Concentration (%) -26 Dilation (%) 23
General Factor (--) -- Plasticity T1 (.degree. C.) 378 T2 (.degree.
C.) 422 T3 (.degree. C.) 455 Max Fluidity 767 Maceral Analysis
(measures) Vitrinite (%) 76.7 Exinite (%) 4.3 Inertinite 6.2
Semi-Fusinite 3.3 Fusinite 4.5 Other 0 Mineral Calc. (%) 5.036 Ash
Analysis Provider (--) Socor SiO2 (%) 46.2 Al2O3 (%) 20.8 CaO (%)
12.5 MgO (%) 0.6 TiO2 (%) 1.1 Na2O (%) 0.6 K2O (%) 2.1 Fe2O3 (%)
6.6 Mn3O4 (%) 0.1 P2O5 (%) 0.2 SO3 (%) 9.3 Physical Properties
Granularity <21 mm (%) -- <19 mm (%) -- <16 mm (%) --
<10 mm (%) 100 <5 mm (%) 97.3 <3.15 mm (%) 89.2 <2 mm
(%) 75.5 <1 mm (%) 50.9 <0.5 mm (%) 32.1 <0.2 mm (%) 15.3
<0.16 mm (%) 12.7 <0.1 mm (%) --
TABLE-US-00004 APPENDIX C Name Poca 3 Proximate Analysis Moisture
(%) -- Ash (%/s) 7.8 Volatile Materials (%/s) 16.4 Volatile
Materials (%/p) 7.78741 Fixed Carbon -- Ultimate Analysis Carbon
(%/s) -- Hydrogen (%/s) -- Oxygene (%/s) -- Nitrogen (%/s) --
Sulfur (%/s) -- Chlorine (%/s) -- Coking Properties Dilatometer
Test T1 (.degree. C.) 431 T2 (.degree. C.) 456 T3 (.degree. C.) 490
Concentration (%) -22 Dilation (%) 63 General Factor (--) --
Plasticity T1 (.degree. C.) 459 T2 (.degree. C.) 477 T3 (.degree.
C.) 504 Max Fluidity 65 Maceral Analysis (measures) Vitrinite (%)
74.5 Exinite (%) 0 Inertinite 11.3 Semi-Fusinite 5.6 Fusinite 4
Other 0 Mineral Calc. (%) 4.548 Ash Analysis Provider (--) -- SiO2
(%) -- Al2O3 (%) -- CaO (%) -- MgO (%) -- TiO2 (%) -- Na2O (%) --
K2O (%) -- Fe2O3 (%) -- Mn3O4 (%) -- P2O5 (%) -- SO3 (%) --
Physical Properties Granularity <21 mm (%) -- <19 mm (%) --
<16 mm (%) -- <10 mm (%) -- <5 mm (%) -- <3.15 mm (%)
-- <2 mm (%) -- <1 mm (%) -- <0.5 mm (%) -- <0.2 mm (%)
-- <0.16 mm (%) -- <0.1 mm (%) --
TABLE-US-00005 APPENDIX D Name Virginia Crews Proximate Analysis
Moisture (%) -- Ash (%/s) 8.5 Volatile Materials (%/s) 26.1
Volatile Materials (%/p) 28.52459 Fixed Carbon -- Ultimate Analysis
Carbon (%/s) -- Hydrogen (%/s) -- Oxygene (%/s) -- Nitrogen (%/s)
-- Sulfur (%/s) -- Chlorine (%/s) -- Coking Properties Dilatometer
Test T1 (.degree. C.) 371 T2 (.degree. C.) 415 T3 (.degree. C.) 469
Concentration (%) -23 Dilation (%) 180 General Factor (--) --
Plasticity T1 (.degree. C.) 395 T2 (.degree. C.) 447 T3 (.degree.
C.) 492 Max Fluidity 2688 Maceral Analysis (measures) Vitrinite (%)
49.2 Exinite (%) 3.6 Inertinite 8.7 Semi-Fusinite 2.9 Fusinite 0.2
Other 0 Mineral Calc. (%) 5.036 Ash Analysis Provider (--) -- SiO2
(%) -- Al2O3 (%) -- CaO (%) -- MgO (%) -- TiO2 (%) -- Na2O (%) --
K2O (%) -- Fe2O3 (%) -- Mn3O4 (%) -- P2O5 (%) -- SO3 (%) --
Physical Properties Granularity <21 mm (%) -- <19 mm (%) --
<16 mm (%) -- <10 mm (%) -- <5 mm (%) -- <3.15 mm (%)
-- <2 mm (%) -- <1 mm (%) -- <0.5 mm (%) -- <0.2 mm (%)
-- <0.16 mm (%) -- <0.1 mm (%) --
TABLE-US-00006 APPENDIX E Name Blue Creek 7 Proximate Analysis
Moisture (%) -- Ash (%/s) 9.2 Volatile Materials (%/s) 19.8
Volatile Materials (%/p) 21.80616 Fixed Carbon -- Ultimate Analysis
Carbon (%/s) -- Hydrogen (%/s) -- Oxygene (%/s) -- Nitrogen (%/s)
-- Sulfur (%/s) -- Chlorine (%/s) -- Coking Properties Dilatometer
Test T1 (.degree. C.) 414 T2 (.degree. C.) 441 T3 (.degree. C.) 486
Concentration (%) -18 Dilation (%) 120 General Factor (--) --
Plasticity T1 (.degree. C.) 415 T2 (.degree. C.) 469 T3 (.degree.
C.) 500 Max Fluidity 719 Maceral Analysis (measures) Vitrinite (%)
80.6 Exinite (%) 0.2 Inertinite 7.8 Semi-Fusinite 5 Fusinite 1
Other 0 Mineral Calc. (%) 5.402 Ash Analysis Provider (--) -- SiO2
(%) -- Al2O3 (%) -- CaO (%) -- MgO (%) -- TiO2 (%) -- Na2O (%) --
K2O (%) -- Fe2O3 (%) -- Mn3O4 (%) -- P2O5 (%) -- SO3 (%) --
Physical Properties Granularity <21 mm (%) -- <19 mm (%) --
<16 mm (%) -- <10 mm (%) -- <5 mm (%) -- <3.15 mm (%)
-- <2 mm (%) -- <1 mm (%) -- <0.5 mm (%) -- <0.2 mm (%)
-- <0.16 mm (%) -- <0.1 mm (%) --
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