Note: Descriptions are shown in the official language in which they were submitted.
1! 1 6 ~
. our recent energy crisis highlighted the importance
of extending our liquid hydrocarbon resources and of
conserving them for uses other than as fuels. The im-
portance of coal as an abundant source of ener~y for fuel
purposes was clearly indicated, but coal, being a solid,
is difficult if not impossible to handle in a simpl~ feed
system havinq uniform fuel properties. Therefore it would
be hiqhly desirable to be able to handle coal as a liquid
~uel where it could be furnished to combustion equipment
as a stable, pumpable slurry of uniform consistency.
'~
~,
, 6 ~
Heretofore, various slurries of coal have been
prepared but such slurries have various difficulties
associated with them in that the particles of coal settle
to the bottom under static conditions making it difficult
or impossible to utilize the coal or combustible solids
in the slurry due to a non-uniform slurry composition
containing various proportions of solids and liquids
resulting in some cases in an unpumpable compacted paste
containing most of the solids and a fluid liquid con-
taining little of the solids. Therefore, it is highly
desirable to have coal slurries which are prepared such
that the coal particles or other combustible solids are
uniform in size and distribution throughout the slurry
and such that the solids do not settle out thus making
such specially prepared coal or combustible solids slurry
in a form that has a uniform composition of solids and
liquids and in a form that is capable of being delivered
to various combustion devices as a stable, pumpable,
uniform and non-settling composition~
In preparing the "fluid coal" of this invention, it
is necessary to comminute large particles of coal into
smaller particles. Comminuting coal in a dry state is
hazardous because the presence of coal dust in air due
to such comminution forms an explosive mixture. In addi-
tion, where coal is first comminuted and then added to
the emulsion, apart from the explosive hazard and the
difficulty of incorporating large concentrations of coal
in the emulsion~ the process involves two steps.
We have now discovered a process which comprises the
in situ comminution of coal in the emulsion or during
a stage in the preparation of the emulsion~ Thus, the
. . ~ . .
~ 1 6~,~,69
present process is essentially a one step process which
avoids the necessity of a two step process of first
comminuting coal separatel~ in a dry state, with the
accompanying problems of explosive coal dust and then
adding the dry comminuted coal to the emulsion.
According to one aspect of t:he invention there is
provided a process of preparing a non-settling coal-
containing emulsion which comprises adding coal, in an
amount of about 30% to about 60~ by weight, to a high
internal phase ratio emulsion or during the preparation
of a high internal phase ratio emulsion, said emulsion
comprising an emulsifying agent, an emulsifiable oil and
water, said water being the external phase, and comminut-
ing the coal in situ.
According to another aspect of the invention there is
provided a method of preparing a stabilized fuel slurry
having liquid fuel oil present in the range of from about
32% by weight to about 45% by weight, solid fuel particles
with diameters as large as about 1/4" present in the range
of from about 30% by weight to about 60~ by weight, water
present in the range of from about 4.5% by weight to about
5% by weight and an emulsifier capable of forming a thixo-
tropic water external-oil high internal phase emulsion
present in the range of from about 0.5% by weight to about
5% by weight, said method comprising adding solid fuel to
a high internal phase ratio emulsion or during the prepara-
tion of a high internal phase ratio emulsion, agitating
the mixture to form a thixotropic water external~oil high
internal phase emulsion and to comminute the solid fuel
particles, to form a stabilized fuel slurry having solid
fuel particles with diameters as large as about 1/4 inch.
fi 9
According to yet another aspect of the invention
there is provided a method of preparing a stabilized coal
slurry comprising adding solid coal to a high internal
phase ratio emulsion or during the preparation of a high
internal phase ratio emulsion, agitating the mixture to
form a thixotropic water externall-oil high internal phase
emulsion and comminuting the coal ln situ~
The stable, pumpable, uniform, non-settling coal
slurries formed by in situ comminution can be handled as
uniform compositions, i.e., the coal or solids will not
settle out when the mixture is either in a static or a
dynamic state. Stated another way, the coal or combus-
tible solids slurries of this invention can be handled
and stored as stable, uniform, pumpable, non-settling
compositions without incurring the problems associated
with slurries in a static mode, i.e., the problems
associated with slurries in storage or interim use where
the solids might settle and thereby produce non-uniform
compositions which have unstable pumping cycles and
combustion characteristics.
For example, when slurries of coal in oil are prepared
for injection into steel mill blast furnaces, the particles
of coal settle out thus making it difficult to pump a fuel
to the furnace which has a uniform solids/liquid compo-
sition. Petroleum in various forms has been used in
blast furnace operations and thus petroleum or water/oil
emulsions or suspensions of petroleum have been employed.
~lowever in view of the abundance and relative low cost of
coal, it is highly desirable to extend the use of petroleum
3~ as a fuel. Therefore being able to handle coal as a fuel
extender in a stable, pumpable, uniform, non-settling
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1 3 ~ , 6 9
slurry form similar to that used for petroleurn fuels or
water-petroleum emulsions is highly desirable.
Our method produces oil emulsions which are heavily
loaded with coal or other combustible solids and which can
be handled and pumped with the ease of petroleum, while
making use of the low cost and availability of coal or
other solids. By this method emulsions of fluid coal can
be delivered as a fluid to a combustion chamber regardless
of the composition's previous static or dynamic state.
Coal-loaded emulsions can be prepared by a variety
of methods, including the Eollowing:
(1) The emulsion is first prepared and the coal added
thereto is comminuted in situ;
(2) The exterior phase, such as water and emulsifier,
is placed in a vessel, and the coal added thereto is
comminuted as oil is added to the vessel to prepare the
emulsion;
(3) The water-emulsifier exterior phase is added to a
vessel and the coal added thereto is comminuted in situ
so that the coal particles are thoroughly wetted with the
water-emulsifier mixture. Thereupon, oil is added to the
water-emulsifier-comminuted coal system with mixing to
form the coal-loaded emulsion;
(4) Coal was thoroughly wetted with the water-emulsifier
system and the oil phase was added thereto as the coal is
comminuted to yield a coal-loaded non-settling emulsion.
(5) Processes combining features of the above 4 processes.
The comminuted coal employed may be any size which can
be prepared into the emulsions of this invention such as
about 1/4" or less, for exampler about 1/8" or less, but
preferably about 14 to 16 Mesh or less with an optimum of
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about 30 Mesh or less, including as low as 200 Mesh. The
particular size will depend upon the type of coa~ avail-
able, the system in which it is to be used, the available
equipment, etc.
The amount of coal in the emulsion may be at least
about 30% by weight, such as at least about 40%, for
example at least about 50%, but preferably at least 40
with an optimum of about 50-60~.
The oil employed may be any of the substances which
are practically insoluble in water. These include the
animal oils of both land and marine animals; vegetable
oils, petroleum or mineral oils of various classes
including those of open chain hydrocarbons, cyclic
hydrocarbons or cycloparaffins; resin oils and wood
distillates; various oils obtained from petroleum pro-
ducts such as gasolines, naphthas, gas fuel, lubricating~
residual, and heavier oils; coal distillate inc~uding
benzene, toluene solvent naphtha, cresote oil and
anthracene oil and coal tar.
In the preferred embodiment the coal is substantially
wetted with the water-emulsifier system before or during
comminution and the oil phase added thereto to form the
coal-loaded emulsion.
A wide variety of emulsifiers can be emplo~ed in
preparing the slurries of this invention including
cationic, anionic, nonionic, ampholytic or combinations
thereof, such as for example the emulsifier described in
U.S.P. 3,732,16~. The preferred type of emulsifier is
nonionic.
The emulsifier employed in the following examples is
described in Emulsifier Example 1.
1~6~ 3~
Emulsifier Example 1
The emulsifier used is a blend of three o~yalkylated
compounds, The first compound (1) is an oxyethylated
dinonylphenol using ~.29 weights of ethylene oxide per
weight of dLnonylphenol. The second compound (2) is an
oxyalkylated linear alkyl chain C-8 to C-10 alcohol using
1.0 weights of propylene oxide and then 2.0 weights of
ethylene oxide per weight of alcohol. The third compound
(3) is an oxyalkylated butylphenol formaldehyde resin
using 80~0 weights of propylene oxide and then 80.0
weights of ethylene oxide per weight of resin. These
compounds are blended with water using 80 wt % water and
20 wt % emulsifier blend which is 31.5 wt % compound (1),
37.7 wt % compound (2) and 30.8 wt % compound (3).
The following examples are presented by way of illus-
tration and not of limitation.
Example A
The following example illustrates the preparation of a
coal-water slurry (i.e., non-emulsion slurry).
A mixer, a jacketed, high speed impeller-grinder, was
used. First a mixture of coal and No. 6 residual fuel oil
was produced. Thirty five pounds of oil were introduced
into the mixer and with the lid closed and the impeller
running, 35 pounds of Illinois coal were added in about
two minutes, and the mix allowed to grind for 10 minutes
with the temperature reaching about 160F. resulting in a
fluid gritty slurry. However, the coal solids settle out
rapidly and within two hours most of the coal had settled.
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i i ~ rJ ~ r~ y
Example B
Using the same equipment and operatlng procedure
of Example A, emulsions containing the coal were prepared.
Emulsifier and water were firs-t placed in the mixer using
1.75 pounds of emulsifier and 4.~5 pounds water. Approx-
imately 5 pounds of residual fuel oil was added until the
total liquid level reached the mixer impeller. The lid
was then closed and the mixer started. The remaining
-approximately 24 pounds of xesidual oil was then added
1~ through a port while the mixer was running producing an
80/20 oil-in-water emulsion. The Illinois coal was then
added, 35 pounds, and -this mixture ground for 10 minutes. A
non-settling emulsion containing 50% by wt coal was produced.
Example C
Using the same procedure as Example A, another
slurry emulsion was produced using 0.875pounds emulsifier,
2.625 pounds water, 31.5 pounds of residual oil and 35
pounds of coal. Resulting mixture was a non-settling
emulsion containing 50% by weight coal.
Example D
The procedure of Example A was repeated using 0.4
pound emulsifier, 3.1 pounds water, 31.5 pounds of cGal tar
and 35 pounds coal. The resulting mixture was a non-
settling emulsion containing 50% by weight coal and 45% by
weight coal tar.
.
Example E
Another mixture was produced according to the follow-
ing procedure. Emulsifier, 0.4 pounds, and water, 3.1 pounds,
were mixed and l pound of this water-emulsifier blend
was placed in a twin-cone blender with 35 pounds of
coal and tumbled 'or one hour, -thoroughl~ wetting the
coal. ~his wetted coal and the remaining 2.5 pounds of
emulsifier-water mixture were loaded into the mixer of
Example A and 31.5 pounds of residual fuel oil were
added while the mixer was running. This mixture was
mixed for lO minutes with the temperature being held to
120 with cooling water. The resulting mixture was a
non-settling emulsion containing 50~ by weight coal and
45~ by weight residual oil.
Ex mple F
Another procedure for producing these coal slurry
emulsions was as follows: The coal was weighed into a
container and the required amount of emulsifier-water
mixture added and thoroughly mixed with the coal until the
coal was completely wetted at which time the fuel oil or
coal tar was added and mixed with the wetted coal producing
non-settling coal/fuel oil or coal/coal tar emulsions.
The following table is a summary of emulsified
coal formulations.
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3 ~ 9
m Ln
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r-( I I ~n l ~r ~r l l ~ l~ ~r
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n It t
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U~ Ln
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Ln I I q~ I r J ~ I I ~ I al .
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S
I I O IO I ~CO I It~ IO~
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.
u~I I ! I ~ I I 1~ o~ I Ln
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h
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U ~
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m r-l ~rl E~ Ul ~ U r-l m r~ l Lû ~ Ot~
~ X S-J ~ h ~ ~ # h a)S l rd O O
e ~ e = I ~ h C.) Z;
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X ~ ~ t~ O ~ (~ ~X ~ r-l ~ O ~D ~ ~ ~ m
rS~, _I ~ U ~ X 3 U W r~ #: ~ U X 3 ~ *
3 ~ 9
The emulsions of this invention have a high internal
oily phase and a low external non-oily phase. High
internal phase ratio emulsions have been described in
the following patents and the materials and methods
disclosed therein may be employed in practicing the
present invention:
U.S.P. 3,343,599 METHOD OF REDUCING THE POROSITY OF
SUBTERRANEAN POROUS FORMATIONS
U.S.P. 3,352,109 HYBRID THIXOTROPIC ROCKET AND JET FUELS
COMPRISING OIL IN WATER EMULSIONS
U.S.P. 3,378,418 METHOD OF RESOLVING THIXOTROPIC JET AND
ROCKET FUEI, E'MULSIONS
U.S.P. 3,396,537 HYBRID FUEL II
U.S.P. 3,490,237 THIXOTROPIC OIL-IN-WATER EMULSION FUELS
U.S.P. 3,523,826 PROCESS OF CLEANING PIPING SYSTEMS
U.S.P. 3,539,406 ESSENTIALLY NONAQUEOUS EMULSIONS
U.S.P. 3,565,817 CONTINUOUS PROCESS FOR THE PREPARATION
OF EMULSIONS
U.S.P. 3,613,372 METHOD OF PROVIDING POWER WITH
ESSENTIALLY NONAQUEOUS EMULSIONS
U.S.P. 3,617,095 METHOD OF TRANSPORTING BULK SOLIDS
Since the particles of coal are packed into the
emulsion structure, it is difficult to state whether the
coal, which is preferably water wetted, is part oE the
aqueous phase or suspended in an emulsion but not a part
thereof. We do not wish to be bound by theoretical
considerations as to the type of emulsion provided the
emulsion possesses the desired characteristics of the
present invention. Regardless of the type of emulsion, hy
in situ comminution, the particles of coal are dispersed
and
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3 ~; ~3
packed into the emulsion so as to form "fluid coal"
possessing the characteristics of the present invention.
The coal slurries of this invention can be burned
in blast furnaces, in turbine engines, in magneto hydro-
dynamic generators, in direct firecl boilers, as well as
in other combustion systems. At prPsent prices the cost
savings of a 50% by weight coal/oil slurry is approximately
as follows:
(1) Residual oil = $2.00/million BTU
(2) Residual oil ~ coal = $1.43/million BTU.
Use Example
The coal slurry emulsion of Example E was stored
for approximately 2 weeks without evidence of settling.
The slurry emulsion was then circulated and heated to
160F for two hours while being injected into one lance
of a blast furnace. After injection, the feed lines and
lance showed no evidence of plugging or coking and
operation of the blast furnace was satisfactory~
Similarly the slurry emulsions can be utilized
in firing steam boilers, turbines and other direct fired
combustion systems as well as in magneto hydrodynamic
generators wherein the suspended solids will assist in
developing highly ionized gases used for increased
generator efficiency.
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