U.S. patent application number 09/768714 was filed with the patent office on 2002-02-07 for system and process for agglomeration and processing of carbonaceous fines and dust.
Invention is credited to Agarwal, Pradeep, Agnew, John B., Filippis, Paolo De, Linjewile, Temi M., Plancher, Henry.
Application Number | 20020014155 09/768714 |
Document ID | / |
Family ID | 26873695 |
Filed Date | 2002-02-07 |
United States Patent
Application |
20020014155 |
Kind Code |
A1 |
Agarwal, Pradeep ; et
al. |
February 7, 2002 |
System and process for agglomeration and processing of carbonaceous
fines and dust
Abstract
A system and process for agglomerating and processing
carbonaceous fines is provided. The process comprises powdering the
carbonaceous fines, mixing the powdered carbonaceous fines with an
organic liquid creating a slurry, adding a predetermined amount of
an aqueous electrolyte to the slurry creating agglomerated
particles, settling the large agglomerated particles resulting in a
settled mixture of agglomerated coal fines and reagent liquor, and
separating the agglomerated coal fines from the reagent liquor.
Inventors: |
Agarwal, Pradeep; (Laramie,
WY) ; Filippis, Paolo De; (Rome, IT) ;
Linjewile, Temi M.; (Laramie, WY) ; Agnew, John
B.; (Glen Osmond, AU) ; Plancher, Henry;
(Laramie, WY) |
Correspondence
Address: |
Emery L. Tracy
730-29th Street
Boulder
CO
80303
US
|
Family ID: |
26873695 |
Appl. No.: |
09/768714 |
Filed: |
January 24, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60177829 |
Jan 25, 2000 |
|
|
|
Current U.S.
Class: |
95/195 |
Current CPC
Class: |
B01D 47/06 20130101;
B01D 51/02 20130101 |
Class at
Publication: |
95/195 |
International
Class: |
B01D 047/00 |
Claims
What is claimed is:
1. A method for agglomerating and processing carbonaceous fines,
the process comprising: a) powdering the carbonaceous fines; b)
mixing the powdered carbonaceous fines with an organic liquid
creating a slurry; c) adding a predetermined amount of an aqueous
electrolyte to the slurry creating agglomerated particles; d)
settling the large agglomerated particles resulting in a settled
mixture of agglomerated coal fines and reagent liquor; and e)
separating the agglomerated coal fines from the reagent liquor.
2. The method of claim 1 and further comprising: removing the
reagent liquid.
3. The method of claim 2 wherein the reagent liquid is removed by
washing the agglomerated coal fines.
4. The method of claim 2 and further comprising: recycling of the
reagent liquid.
5. The method of claim 1 and further comprising: compacting the
agglomerated coal fines into a desired solid product shape.
6. The method of claim 5 wherein the agglomerated coal fines are
compacted using a filter press.
7. The method of claim 1 wherein the carbonaceous fines are
selected from the group consisting of anthracite coal, bituminous
coal, coke, calcined coke and carbon black.
8. The method of claim 1 wherein the organic liquid is a solution
of heavy hydrocarbon containing a carbonyl-group.
9. The method of claim 1 wherein the aqueous electrolyte is
selected from the group consisting of organic and inorganic.
10. The method of claim 1 wherein the agglomerated coal fines are
separated from the reagent liquor by a process selected from the
group consisting of settling, decantation, centrifugation, and
filtration.
11. The method of claim 1 and further comprising: spraying the
reagent liquor onto a source of air-borne carbonaceous dust.
12. The method of claim 11 and further comprising: adding water to
the reagent liquor.
13. The method of claim 11 wherein the reagent liquor is sprayed
with spraying equipment generating predetermined dispersion and
coverage of the air-borne carbonaceous dust.
14. A system for agglomerating and processing carbonaceous fines
utilizing the method of claim 1.
15. A system for agglomerating and processing carbonaceous fines
utilizing the method of claim 2.
16. A system for agglomerating and processing carbonaceous fines
utilizing the method of claim 4.
17. A system for agglomerating and processing carbonaceous
comprising: means for powdering the carbonaceous fines; a mixing
apparatus for mixing the powdered carbonaceous fines with an
organic liquid, the mixed powdered carbonaceous fines and organic
liquid creating a slurry; means for adding a predetermined amount
of an aqueous electrolyte to the slurry creating agglomerated
particles; a settler apparatus for settling the large agglomerated
particles resulting in a settled mixture of agglomerated coal fines
and reagent liquor; and means for separating the agglomerated coal
fines from the reagent liquor.
18. The system of claim 17 and further comprising: means for
removing the reagent liquid.
19. The system of claim 17 and further comprising: means for
recycling of the reagent liquid.
20. The system of claim 17 and further comprising: a compaction
apparatus for compacting the agglomerated coal fines into a desired
solid product shape.
Description
[0001] The present application is a continuation of pending
provisional patent application Ser. No. 60/177,829, filed on Jan.
25, 2000, entitled "Process for Agglomeration and Processing of
Carbonaceous Fines and Dust".
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates generally to a system and process for
the agglomeration of carbonaceous particles and, in particular, it
relates to the agglomeration of coal and coke fines, collected in
cyclones, bag houses and other particle separation systems, in a
slurried medium. The present invention further relates to the
agglomeration of potential fugitive carbonaceous dust in
process/mining and transportation environment through application a
spray. The system of additives described herein, mixed in varying
proportions, can be used for the above and related applications for
recovery, suppression and utilization of carbonaceous fines and
dust.
[0004] 2. Description of the Prior Art
[0005] Coal dust is a generally unwanted but inevitable fact of
life in most phases of coal utilization technology. It is known
that powdered coal, i.e., coal dust, is produced in great
quantities during mining of coal, during its handling before and
after shipment, and during shipment and storage. The coal powder is
the result of the mechanical effects of mining and grinding
processes. Similarly, the transport or handling of coal has the
effect of inducing contact between large pieces of coal and results
in the creation of fines. Coal powder is also due to weathering and
oxidation of stored coal.
[0006] The formation of powdered coal leads to several significant
problems. Powdered coal can lead to environmental disturbances,
including both threats to health and vegetation and aesthetic
damage. Powdered coal can permeate the air of mining sites or other
work sites and is highly flammable and explosive. An additional
problem is that when powdered coal cannot be used, its economic
value and energy value is totally lost. For these and other
reasons, systems for collecting and reducing the dispersal of coal
dust must be used.
[0007] In the past, the principal means relied on for abatement of
fugitive dust from manufacturing facilities are cyclones,
electrostatic precipitators, fabric filters, and scrubbing. Because
of the high collection efficiency, bag houses are used in many
shipping mines. The bags are then shaken down and the coal dust is
placed on conveyors to be loaded into railroad cars for shipping.
Because of danger of spontaneous combustion, as little coal dust as
possible is stored or stockpiled over long periods of time.
[0008] A particularly difficult dust problem arises out of the
handling of calcined coke. Since the particulate calcined coke is
fragile, its movement generates calcined coke dust that is
collected through an air/recovery bag house system. When the bag
house dumps the collected calcined coke dust, it is discharged
either to a waste container or back onto the coke being transported
that compounds the dust load. The disposal is difficult,
cumbersome, and wasteful of an otherwise useful product whereas
return of collected dust increases the likelihood of its release to
the outside atmosphere.
[0009] In the following, distinction is made between:
[0010] the carbonaceous--coal, char, and coke--particles collected
in particle separation devices described earlier; this is hereafter
referred to as Case A
[0011] the carbonaceous--coal, char and coke--dust, for example in
process/mining environment, which has the potential to become
air-borne during loading/unloading, transportation on conveyor
belts or otherwise; this is hereafter referred to as Case B.
[0012] In the past, in order to reduce the problem of coke and coal
fines with reference to Case A, a variety of methods have been
proposed. These prior methods are primarily off-line methods.
Processes are known where coal fines are subjected to various
conditions, typically high heats and/or pressure, and then
mechanically compressed or formed into pellets or briquettes.
Unfortunately, these processes have energy and equipment
requirements that make them unattractive and expensive for most
coal dust reduction applications.
[0013] A variety of methods used for producing compact coal dusts
such as pellets or briquettes from coal fines involve the use of
binders such as sulfite lye, urea-formaldehyde resins,
phenol-formaldehyde resole resins, polyvinyl alcohol, or bitumen.
However, these known processes have disadvantages. The addition of
inorganic material tends to increase the ash content of the coal
fines compact thus reducing the fuel value of the coal. In
addition, many organic binders make the coal fins/binder mixture
sticky and difficult to handle. Furthermore, the organic substances
used are expensive and require particular precautions during
handling.
[0014] In the case of coke dust production, the use of aqueous
asphalt emulsion and surface-active agents has been proposed.
Unfortunately, none of these dust control references offer a
suitable solution for the recovery of coke dust. Perhaps this
inadequacy is because the coke dust is neither mineral nor coal,
both by definition and wetting characteristics.
[0015] As regards to Case B--essentially an on-line dust mitigation
strategy--a variety of chemical mixtures, applied in the form of a
spray, have been used in the past. Many of these conventional
methods employ comparatively expensive chemicals. According to
practitioners, the efficacy of the agglomerating mixtures is
short-lived in many cases. The stability, under the wide range of
ambient temperature conditions encountered in practice, has also
been somewhat limited.
[0016] Therefore, a need exists for a low-cost method for the
recovery and handling of coal fines--for Case A as well as Case B.
Additionally, there exists a need for a system and process for
agglomerating coal, coke, and more general, carbonaceous matter
fines as generated from many different sources. Further, a need
exists for a system of providing additives, mixed in varying
proportions, for use in the recovery, suppression, and utilization
of carbonaceous fines and dust in process/mining/transportati- on
environments. Still further, there exists a need for a process
having significant economic advantages over past attempts in the
field in that little energy input is required and much of the
process chemistry is recycled.
SUMMARY
[0017] The present invention is method for agglomerating and
processing carbonaceous fines is provided. The process comprises
powdering the carbonaceous fines, mixing the powdered carbonaceous
fines with an organic liquid creating a slurry, adding a
predetermined amount of an aqueous electrolyte to the slurry
creating agglomerated particles, settling the large agglomerated
particles resulting in a settled mixture of agglomerated coal fines
and reagent liquor, and separating the agglomerated coal fines from
the reagent liquor.
[0018] The present invention further includes a system for
agglomerating and processing carbonaceous. The system comprises
means for powdering the carbonaceous fines. A mixing apparatus
mixes the powdered carbonaceous fines with an organic liquid with
the mixed powdered carbonaceous fines and organic liquid creating a
slurry. Means are provided for adding a predetermined amount of an
aqueous electrolyte to the slurry creating agglomerated particles.
A settler apparatus settles the large agglomerated particles
resulting in a settled mixture of agglomerated coal fines and
reagent liquor. Means are provided for separating the agglomerated
coal fines from the reagent liquor.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is a flow chart illustrating the process for
agglomerating and processing carbonaceous fines for Case A, in
accordance with the present invention; and
[0020] FIG. 2 is a flow chart schematically illustrating a process
for agglomerating and processing carbonaceous fines for Case B, in
accordance with the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0021] As illustrated in FIG. 1, the present invention is a system
and process, indicated generally at 10, for the agglomeration of
coal, coke, and more general carbonaceous matter fines. As
described above, distinction is made between:
[0022] Case A--the carbonaceous--coal, char, and coke--particles
collected in particle separation devices; and
[0023] Case B--the carbonaceous--coal, char, and coke--dust, for
example in process/mining environment, which has the potential to
become air-borne during loading/unloading, transportation on
conveyor belts or otherwise.
[0024] For Case A, the process of the present invention comprises
collecting fines of appropriate size, slurrying the fines with
agglomeration reagents and solvents, and then separating and
pelletizing agglomerated coal fines, thereby removing reagent
liquor from fines.
[0025] Carbonaceous matter with particulate sizes less than 0.3
(mm) millimeters are selected for treatment. It should be noted,
however, that the process of the present invention can be utilized
with any size particle including particles having a size equal to
or greater than 0.3 (mm) millimeters. Micron-sized particulates are
of special interest in dust suppression applications since such
particles are not easily reclaimed from coal washery wastes due to
slow sedimentation rates in disposal ponds.
[0026] The agglomeration process for Case A involves the following
steps:
[0027] a) Mixing powdered carbonaceous material or particles 12
with a solution of a heavy hydrocarbon 14 with an organic liquid
containing a carbonyl group in a mixer 16. The formed slurry is
utilized as a vehicle for the agglomerating agent;
[0028] b) Sending the formed slurry to a settler 18 and adding to
the obtained slurry a predetermined amount of an aqueous
electrolyte 20 (organic or inorganic). The addition of the
electrolyte immediately results in the formation of large
agglomerated particles which settle within a few minutes resulting
in a settled mixture of agglomerated coal fines and reagent
liquor;
[0029] c) Separating the agglomerated coal fines 22 from the
reagent liquor by settling or decantation. It should be noted that
other types of separation including, but not limited to,
centrifugation, filtration, etc., are within the scope of the
present invention. The agglomerated coal fines at this stage form a
sludge that can also be processed further by washing to remove the
hydrocarbon-based solution if the agglomerated coal fines are
intended to be disposed in a landfill. Alternatively, the separated
fines can be sent to a combustion furnace;
[0030] d) Compacting, if desired, the resultant sludge product into
the desired solid product shape in a compactor 24. In order to
accomplish compacting, a filter press can be used. This leads to
the simultaneous recovery of the hydrocarbon-based solution 26. The
recovered hydrocarbon-based solution can then be recycled to the
mixing device for preparation of the slurry in step a), as
illustrated in FIG. 1; and
[0031] e) Recycling of the liquid phase. The liquid phase recovered
from the step c) can also be recycled to the mixing device for
preparation of the slurry in step a), as illustrated in FIG. 1.
[0032] Generally, temperature is not a concern in the agglomeration
process of the present invention, but it may have significant
peripheral advantages in the recovery of the solvent and in the
characteristics of the final product. Operation at room temperature
will permit sufficient fluidity of the hydrocarbon-based solution
and the slurry. Furthermore, operation at room temperature provides
the most cost-effective recovery.
[0033] Since the treatment system and process for the agglomeration
and processing of carbonaceous fines and dust 10 of the present
invention renders the surface of the resultant product hydrophobic,
the treated and compressed product is remarkably resistant to water
absorption. The advantage of the present invention results from the
ability to produce the desired product under conditions utilizing
low energy and high solvent recovery.
[0034] The process of the invention disclosure is useful to
agglomerate any type of carbonaceous fines. For example, the
carbonaceous fines can be selected from anthracite coal, bituminous
coal, coke, as well as calcined coke or carbon black.
[0035] For Case B, the solution reagents 28, described above,
diluted in an aqueous medium 30, i.e., water, are sprayed onto the
source of fugitive or air-borne carbonaceous dust. Additional water
may be used as a carrier-fluid to reduce cost of application, as
illustrated in FIG. 2. Atomizers and related spraying equipment 32
can be used if necessary to generate sufficient spray 34 dispersion
and coverage. In the case of transportation using conveyor belts,
application at several locations along the belt may be necessary.
The application in this form will reduce fugitive dust during
transportation, i.e., in rail cars, barges, etc., and also reduce
the propensity for moisture readsorption and spontaneous
combustion.
[0036] The following examples will serve to illustrate the
invention for the preparation methods for the hydrocarbon-based
solution:
EXAMPLE 1
[0037] A solution of heavy gas-oil and a molecule containing the
carbonyl functionality, for example, methyl ethyl ketone, in the
ratio of 1:1 were mixed with fines particle of coal dust having a
size less than thirty (<30.mu.) micron and containing less than
ten (10%) percent by weight moisture. The produced slurry contains
thirty-five (35%) percent by weight of coal. Addition of 0.5 (%)
percent by weight of aqueous electrolyte (fifty (50%) percent
concentration in water) was added to this mixture and, within a few
minutes, large agglomerate particles settled, forming a descending
interface between an upper clarified solution and a lower layer
opaque liquor containing suspended matter. Within thirty (30)
minutes (or less) the agglomerated particles settle to the bottom
of the container vessel forming a compact sludge. The clarified oil
solvent mixture can be removed and reused. The sludge layer,
containing the carbonaceous matter, can be washed and dried to give
a compact solid.
EXAMPLE 2
[0038] Five hundred (500 g) grams of coke fines (less than two
hundred (<200) mesh) and emulsion base (thirty-seven (37 mL)
milliliters) prepared with the following composition (SAE 10 W
motor oil (API CC. CD-Sf): 54.3%; Water: 42.5%; Solvent: 1.0, for
example, methyl ethyl ketone; and electrolyte: 2.2%) were placed
into a one-gallon paint container and mixed with 3250 ml of water.
The recovered fines were dried at sixty-five (65.degree. C.)
Celsius. Significant agglomeration was noted since the particle
sizes were, in general greater than those corresponding to two
hundred (200) mesh. Visual characterization also suggested the
tendency for the solids to form clumps.
EXAMPLE 3
[0039] Coke fines (0.5 g, <200 mesh) and three (3) mL of water
were treated with trace amount of Syncrude derived residue rich in
pyridinic moeties, and trace amount of electrolyte. This led to a
very rapid, and possibly complete, settling of coal fines
suggesting strong agglomeration. The clarified solvents can be
removed and reused. The sludge layer, containing the carbonaceous
matter, can be washed, dried and compacted; the liquid can be
recycled.
EXAMPLE 4
[0040] The solutions prepared as described in Examples 1-3 were
applied in the form of a spray, using an air-brush, to piles of
coal and coke fines (less than two hundred (<200) mesh). Visual
examination confirmed that the tendency to generate dust was
significantly lower in the presence of convective wind flow over
the top of the piles of carbonaceous particles. Visual
characterization also suggested the tendency for the solids to form
clumps.
[0041] For the examples described, other electrolytes have been
also found effective, for example sulfuric acid, phosphoric acid,
sodium hydroxide, ammonia and salts solutions, as well as organic
acids.
[0042] The foregoing exemplary descriptions and the illustrative
preferred embodiments of the present invention have been explained
in the drawings and described in detail, with varying modifications
and alternative embodiments being taught. While the invention has
been so shown, described and illustrated, it should be understood
by those skilled in the art that equivalent changes in form and
detail may be made therein without departing from the true spirit
and scope of the invention, and that the scope of the present
invention is to be limited only to the claims except as precluded
by the prior art. Moreover, the invention as disclosed herein, may
be suitably practiced in the absence of the specific elements that
are disclosed herein.
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