Note: Descriptions are shown in the official language in which they were submitted.
.1
I'lTLE OF THE INVENI`ION
PROCESS ~OR PREPARING OIL-C()NTAINING GRANUI,AR COAL
BACI~GROUND OF THE INVENTION
The present invention relates -to a process for
preparing oil-containing coal granules from an aqueous
slurry of coal par-ticles.
A process is known for separating a coal o-f
high quality from an aqueous slur~y of coal par-ticles
having suspended -therein in mixture wlth the coal parti-
cles mineral par-ticles and pollutan-ts which are not
suited for use as fuel, by adding a hydrocarbon oil to
the slurry and vigorously agitating the mixture to selec-
tively ag~lomerate or granulate the coal particles with
the hydrocarbon oil serving as a binder. The process,
which is called oil a~glomeration, utilizes the proper-ties
of the hydrocarbon oil that coal particles are readily
wettable with the oil but mineral particles and pollutants
are not easily wettable therewith. The process is used,
for example, for recovering fine coal particles from the
waste water from coal prepara-tion processes, for separa-t-
ing ash from coal and for improving the quality o~ coal
separa-ted from aqueous coal slurries transported by pipe-
lines. However, since -the conven-tional process uses a
low-boiling hydrocarbon oil which has a relatively low
. . ~ ,
viscosity and which is expensive, the agglomerate or granular coal
prepared is very costly.
SUMM~~Y 0~ ~ INVENTION
The present invention, which has overcome the above
problem, provides a process for preparing an oil-eontaining
granular eoal eomprising the steps of adding to a slurry of eoal
particles in water a liquid oil mixture of a low-boiling hydrocarbon
oil and a high-boiling hydroearbon oi:l soluble in the low-boiling
hydroearbon oil and in the form of a sol.id or paste at room
temperature, and a surfaetant granulating the eoal partieles in
the water with use of` the oil mixture as a binder, separating the
resulting coal granules eontaining the oil mixture from the water,
and heating the eoal granules eontaining the oil mixture to
evaporate the low-boiling hydroearbon oil. This proeess affords
an oil-eontaining granular eoal whieh is eomposed of the eoal
partieles and the high-boiling hydroearbon oil in the form of a
solid or paste at room temperature. Beeause this proeess gives
hard coal granules of good quality with use of a high-boiling
hydroearbon oil, sueh as residuum oil, whieh is inexpensive, the
process is useful, for example, for recovering fine coal particles
from the waste water from eoal preparation processes, for
separating ash from coal and for improving the quality of coal
separated from aqueous eoal slurries transported by
.~
J'6~
pipelinesO The process is very economical and requires
only a short period of -time -for granula-tion. 'rhe oil-
con-taining coal granules ob-tained are hard and will no-t
s-tain o-ther devices when placed in-to use. The low-boiling
hydrocarbon oil is recovered by evaporation and is usable
in circula-tion, so -that the use o~ the oil which is
rela-tively expensive will no-t lead to an economica] dis-
advan-tage bu-t assures selec-tive granulation of coal
particles wi-th a grea-tly improved efficiency.
The present invention will be described below
in grea-ter detail with re-ference -to the accompa~ ring
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a block diagram showin~ a specific
mode of the present process;
Fig. 2 is a sectional view schematically showing
a granulating apparatus useful for the present process;
Fig. 3 is a view in section taken along the
line III-III in Fig. 2;
Fig. 4 is a view in section taken along the
line IV-IV in Fig. 2; and
Fig~ 5 is a view in section taken along the
line V~V in Fig. 2.
DESCRIPTION OF THE PR3FERRED EMBODIMENT
With reference to Fi~. 1, a high-boilin~ hydro-
~.lh~O
carbon oi] is dissolved in a low-boll-Ln~ hydrocarbon oil
-to prepare an oil mixture whlch ia l:Lquid at room temper~
ature Examples of preferred hydrocarbon oils are those
having a boiling poin-t of up to 200 C, such as gas oi],
gasoline, kerosene, etc. Examples of useful high-boiling
hydrocarbon oils are hydrocarbon compounds which are
soluble in such low-boiling hydrocarbon oils and which are
in -the form of a solid or pas-te at room temperature,
preferably a-t temperatures of up to 30 C~ ~ore specific
examples of such oils are coal tar, residuum oi]s result-
ing -~rom vacuum distillation processes and cracking
processes, asphalt, fats, resins, waxes, e-tc. At least one
of such high~boiling oils i8 dissolved in one of low-
boiling oils such as those exemplified above to obtain an
oil mixture which is liquid a-t room temperature or
ordinary temperature for use as a binder. To render the
hi~h~boi]ing oil easily soluble, -two ox more kinds of
low-boiling oils are usable in mixture. A surfactant
may be used conjointly. High-boiling oils may be dis-
solved as finely divided into particles or made fluidby being heated to a temperature not lower than the
melting point or softening point.
A usual stirrer or mixer is used for ~reparing
the oi] mix-ture by disso~ving. Subsequently -the oil
mixture serving as a binder is admixed wi-th a~ aqueous
I
i4~D
"
slurry of coal par-ti,cles con-taining m-lneral par-ticles
and pollutants, and -the resl,llting mix-ture is vlgorously
agi-ta-ted. Since the coal particles are selectively
wettable with the low-boiling oil and can be agglomerated
effec-tively by -the oil, the oil along wi-th -the high~
boiling oil dissolved therein forms ag~lomerates of coal
particles. In the above step9 the oil mixture may be
formulated in-to an aqueous emulsion and then admi,xed wi-th
the slurry. A sur:Eactant 7 when used con~jointly, enab]es
the binder to wet and agglomera-te -the coal particles
more effectively. For the agitation, it i5 desirable
-to use a homogeni7,er to sub~ject the mixture of slurry and
oils to a grea-t shearing force.
In some cases, the agglomera-tes of coal thus
formed may be separated by a screen f'rom the aqueous pha,se
of the slurry con-taining the mineral particles and pollu-
tants, but usually the mixture is led into a granulating
machine to granulate the coal particles in the water of
the slurry. The granules of coal, are thereafter separated
from the aqueous phase, i.e. a slurry of ash. The latter
case affords an oil-containing granular coal having a
higher quality and containing less ash and water than the
former.
Fi~s. 2 to 5 show a,n example of .r~ranulating
apparatus 1~ The ap-para,-tus 1 has a hori,~on-tal cylindrical
casin~ 2 closed at i~, opposite ends and a rotary shaft 3
d:isposed coaxially with the casing. ~irst to third agita-
ting blades 4 -to 6 are a-t-tached to the ro-tary shaf-t ~.
~he outer first and -third agi-ta-ting blades 4, 6 include
four radial pla-tes r7~ 8 respec-tively, the Plates of one
blade being displaced from -those of -the o-ther as seen in
~igs. 3 and 5. The central second blade 5 comprise3 an
annular support plate 9 and four curved pla-tes lO attached
to the plate 9 in a spiral arrangemen-t. The coal slurry
containing -the binder i9 introduced in-to -the appara-tus
-through an inlet 11 at the top of the casing 2, and -the
slurry of oil-containing granulated coal in the form of
pellets is discharged from an outlet 12 a-t the bottom of
the casing 2.
~he coal granules -thus formed and containing
the mixture of hydrocarbon oils are soft and easily
collapsible. The granules are heated to evaporate -the
low-boiling oil from the oil mixture. They are hea-ted
indirectly by an external heating jacket or coil) or
directly with hot steam or hot inert gas~ The heating
may be conducted in a vacuum to lower the evaporation
temperature. Some water, when con-tained in the oil-
containing granu~ar coal, produces a steam di~tillation
effect, hence advantageous.
~he coal ~rQnules resultin~ from the evaporation
of the low~boilin~ hydrocarbon oi] are composed of` coal
par-ticles and a hl~h-boilin~ hydrocarbon oil which is in
-the form of a solid or pas-te a-t room tempera-ture, ~o tha-t
they are hard, dry and loose at room -tem~erature. The gas
con-talning -the evapora-ted low-boilin~ hydrocarbon oil is
led into Q condenser, and -the resulting condensate is
separated in a separa-tor tank in-to -the oil and water ~or
-the recovery of the ]ow-boiling oil. ~he oil is then
returned -to the mixer for preparing -the hydrocarbon oil
mi~-ture. Thus the low-boiling hydrocarbon oil is used in
circulation.
The inven-tion will be described with reference
to the following examples, to which the invention,
however, is not limited.
Example 1
~wo parts by weight of residuum oil resulting
from the vacuum distillation of coal and having a sof-ten-
ing point of 50 C was admixed with 10 parts by weight of
kerosene 9 and the mixture was stirred in a four-bladed
mixer a.t 2000 r.p.m. for 5 minutes -to obtain a solutionO
~he oil mixture was a black liquid almost resemblin~
kerosene in fluidity. On the other hand, a bituminous
coal with an ash content of 23~, was pulveri7ed into about
200-mesh (74-~m) particles. A ~00 ~ auan~tity of -the coa1
particles were admixed with 2700 ml of wa-ter to ~re~are
a coal slurry. Il'our contalners were prepa:red each con-
-taining 3000 g of such coal slurry. A 75 g portion of the
oil mixture was placed into one o-f -the con-ta:iners
(Specimen No. 1). A 75 g portion of the oil mixture and
50 ppm ol a nonionic alkanolamide surfac-tan-t were placed
into ano-ther container (Specirnen No, 2). As reference
examples, 75 g of kerosene was placed în-to another con~
-tainer (Specimen No. 4), and 75 g of vacuum resicluurn
oil as divided into fragmen-ts of up -to 1 mm in si~e WclS
placed into the remaining container (S~ecimen No, 5).
Each of the four specimens was treated in a
homogenizer at 2000 r-~p.m. for 2 minutes. As a result,
the coal particles in Specimen No. 2 containing the oil
mixture and surfactant immediately agglomerated, floated
wi-th air bubbles incorporated therein and separated from
an ash slurry. The other three specimens still remained
slurries.
When these three specimens were further agi-tated
in the homogeni~,er for 4 minutes 7 Specimens No. 4 and No.
1 containing kerosene or the oil mix-ture underwent
agglomeration, but Specimen No. 5 remained in the initial
state. Specimen No. 5 was thereafter agitated again for
4 minutes bu-t still remained unchanged. According]y this
specimen (No. 5) was similarly agi-tated as hea-ted to 80
C. ~he coal particles agglomerated finally ln 15 minutes.
Subseqllen-t]y each of the specimens was placed
into -the grQnulating machine shown in Fig~. 2 -to 5 and
agitated at 2000 r.p.rn. for granulatlon. The -time
required for gramllation was rneasured while ob~erving -the
specimen with a stroboscope set to 2000 r.p.m. The oil-
containing ~ranular coal obta~ined was separated from the
ash slurry.
~ inally each of Specimen~ No. l, 2 and 4 was
placed into a flask, and steam (water vapor) having a
tempera-ture of 100 ~ was blown into -the specimen for 2
hours while heating -the specimen with a heating mantle
to distill the kerosene wi-th the steam. The kerosene was
recovered by a liebig condenser. Consequently Specimen
No. 4 afforded coal particles, while Specimens No. l and
No. 2 gave hard pellets which were better than the product
obtained from Speciment NoO 4. The amoun-t0 o~ kerosene
recovered were '70 g from Specimen No. 4, 56 g from Speci-
men No~ 1 and 56 g from Specimen No. 2. The table below
shows the results.
Example 2
The same procedure as in Example l was repeated
with the exception of using the following oil mixture.
A residuum oil obtained by the vacuum dis-tillation of
pe-troleum and having a sof-tening point of 50 C and
kerosene were heated to 60 C to prepare a mix-ture of
6~
]-o
residuum oil and kerosene in -the wei~ht rcltio o-f 2:1 by
-thorou~h s-tirring. The mixture wa~ returned to room
temperature. The oil mix-ture was similar -to bunker -fuel.
The followin~ -table al~o shows the resul-t (Specimen No~ 3).
r-l 0
c~ tL)
o ~ 0u~ r I r
4-1 t~ h 1~ h ~4-1 rl
O O (1) 0 ~~ O O rl
bC -i ~ r I-1~ rl r~l ~
C c~ ri c~ r ~ r~ ~ ~ h
h r~ rl cd O cd Oa) O ~ cd
O o,~ 1~ tr ~ tH P~ Pl N ~; P~
r~ 0 u~ 1~
~; rl rJ rl ~rcJ C rl 0
~ h u~ + ~-~ 0 ~r~
0 0 a) ~ d ~~3 r~ O r
P~; r~ ~ cr~ C~ 5
r~
~rl bfi ~ O
O ~ ~ N t--
I I~
r~ 0 +~ +~+~ rc~ * rcl ~
h 0 CH 4-~tH t~ h 0 ~d
cd a~ O O O O
;1:1 ,C u~ tnc~ ~ r~d 0
0 ~ P~
~_ ~ ~ +~ +~
a~ ~ ~i
r~~ r~ ~ O r-l O r-lO r~l O r I O r-l O
/r ~ r-l u~ _~ ~ r~ r~
o a) cC ¢ ¢ c~
~rl F 4 ~ti O
r~) cd O
t~ * ~` r l r~Is~ ~1 0 $~
~1 r~ ~jo ~ +~
~ 0 ~_ u~ ~ O +~
cd ¢ Z ¢
h a) ~
~r~ ~O ~ D O * *
~r1 ~; r~l
E~ _,
rd '~
~i O O O O O
~I) ~ O O O O O
P~ h O O O O O +~ +~
U~ _~ N (`~1 C\l C\l C\J 5
a~--~ ~ ~ ~
E~ C ~D N ~ ~D *
O r ~ O_~
~rl Ll~ r~
~ rc~ ^
C~ 0 ~ O O O O O O
h 0 ~ O O O O 0_~0 r-l r~
~4 h O O O O O O ri rl
u~ ~-- C\l C\l C\l C\l N C\J O O
r-l . ~i ~
bL` ~^ ~;
b~ ~ c~ O O O O O ,_~0
¢ Q) O C\J C~J C\J C~lCO r~ rc~ -
c~ rl rl r-l
cD ~D O
0 rl Q. r~ 0 C\l h h O
h * h * +~ h * +~
~ r, ~ ~ cD(D ~
h +~ +~ ~) +~ +~ qD c~ ~ ~D ~ ~ C ~< O
0 ,rC ~C X ~ p~ s 1~ a) D
~; ~rl 11~~rl L~\ + O P~ ~rl O + C~ F:L 0 :::; ~ 0 0
,C O ~ t-- cdEi C~ cd 0 ~ r~_ O O Cl)
~rl ~; ~ _~ CH O~ CH O C t-- ~rl ~I h 0
P~l ~ r-l r-l h Lr~ r-l h IS\ h~-- 0 r-l 0 0 cd
rl ~rl ~ rl 5 ~-- ~D cD rl ;~
O O U:) O U'~ ; O
r-l C\~
* * *
C; r-l C\J
cD
p. ~ uoF~ua~ul ~uasa.ld a~,~, x,~ a~
12
The above -table shows -tha-t -the process of -this
invention provi.des a sa-tis~ac-tory oi.l-containing ~ranular
coal in the ~orm of pellet~ and composed o~ coal par-ticles
and a residuwn oil. q'he granula-tion takes only a short
period o:f time, while -the kerosene recovered is re-usable,
hence very economical.
~ he pr0sen-t inven-tion may be embodied dif`ferently
without departing from the spirit and basic fea-tures of
the inven-tion. ~ccordingly the ernbodimer1t herein
disclosed is given for illustrative purposes o~ly and i.s
in no way limi-tative. It is to be understood -that -the
scope of the invention is defined by the appended claims
rather than by the se~cification and that various
al-terations and modifications within -the definition and
scope of the claims are included in the claims.
