U.S. patent application number 15/532716 was filed with the patent office on 2017-11-30 for method and apparatus for manufacturing cokes additive.
This patent application is currently assigned to POSCO. The applicant listed for this patent is POSCO. Invention is credited to Hee-Su KIM, Sangon LEE, Seung-Jae LEE, Sang Hyun PARK.
Application Number | 20170342326 15/532716 |
Document ID | / |
Family ID | 56091885 |
Filed Date | 2017-11-30 |
United States Patent
Application |
20170342326 |
Kind Code |
A1 |
PARK; Sang Hyun ; et
al. |
November 30, 2017 |
METHOD AND APPARATUS FOR MANUFACTURING COKES ADDITIVE
Abstract
Provided is a method and apparatus for manufacturing a cokes
additive, which is optimized for extraction of a cokes additive and
can easily and effectively manufacture the additive, the method
comprising: a coal pre-processing step for bringing coal into
slurry by dispersing the coal in a solvent; a step for introducing
a dispersed iron catalyst while pre-processing the coal; a coal
liquefying step for liquefying the coal slurry by reacting the coal
slurry with a cracking gas; a step for supplying a COG and/or an
LNG as the cracking gas in the coal liquefying step; a separation
step for separating an additive from the liquefied product; and a
recycling step for supplying liquid oil obtained in the separation
step to the coal pre-processing step and using the liquid oil as
the solvent.
Inventors: |
PARK; Sang Hyun; (Pohang-si,
KR) ; KIM; Hee-Su; (Pohang-si, KR) ; LEE;
Seung-Jae; (Pohang-si, KR) ; LEE; Sangon;
(Pohang-si, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
POSCO |
Pohang-si |
|
KR |
|
|
Assignee: |
POSCO
Pohang-si
KR
|
Family ID: |
56091885 |
Appl. No.: |
15/532716 |
Filed: |
June 23, 2015 |
PCT Filed: |
June 23, 2015 |
PCT NO: |
PCT/KR2015/006381 |
371 Date: |
July 5, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C10G 2300/4081 20130101;
C10G 1/00 20130101; C10B 57/06 20130101; C10G 2300/44 20130101;
C10B 49/02 20130101 |
International
Class: |
C10B 57/06 20060101
C10B057/06; C10B 49/02 20060101 C10B049/02; C10G 1/00 20060101
C10G001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 5, 2014 |
KR |
10-2014-0174457 |
Claims
1. A method of manufacturing a coke additive, the method
comprising: a coal pre-processing step of dispersing the coal in a
solvent to form a slurry; a step of introducing a dispersed iron
catalyst while pre-processing the coal; a coal liquefying step of
liquefying the coal slurry by reacting the coal slurry with a
cracking gas; a step of supplying coke oven gas (COG) and/or
liquefied natural gas (LNG) as a cracking gas in the coal
liquefying step; a step of separating an additive from a liquefied
product; and a recycling step of supplying liquid oil obtained in
the separation step to the coal pre-processing step and using the
liquid oil as the solvent.
2. The method of claim 1, wherein in the coal pre-processing step,
dried coal and the solvent are mixed in a weight ratio of 1/1 to
1/4.
3. The method of claim 2, wherein the dispersed iron catalyst is
Fe.sub.2O.sub.3.
4. The method of claim 3, wherein 0.5 to 3.0 parts by weight of the
dispersed iron catalyst is injected for 100 parts by weight of the
coal.
5. The method of claim 1, wherein the separation process comprises
a separating step that separates a gas component from a liquefied
product, a filtration step that separates a liquid material and a
solid material, and a fractional distillation step that separates
an additive by distilling the separated liquid material in the
filtration step, and in the recycling step, the additive and
separated oil in the fractional distillation step are supplied to
the coal pre-processing step.
6. The method of claim 5, wherein the filtration step is performed
at a temperature of 120 to 400.degree. C.
7. The method of claim 6, wherein the fractional distillation step
is performed at a temperature of 200 to 350.degree. C.
8. The method of claim 7, wherein the coal pre-processing step
further comprises a step of crushing the coal and a step of drying
the crushed coal.
9. The method of claim 8, wherein in the coal drying step, the coal
is dried to have a moisture content of 20 wt % or less.
10. The method of claim 7, wherein the coal liquefying step is
performed at a temperature of 250 to 450.degree. C. and a pressure
of 30 to 120 bar.
11. The method of claim 10, wherein in the coal liquefying step,
the cracking gas is supplied and heated at a temperature of 300 to
600.degree. C.
12. A coke additive manufacturing apparatus, comprising: a mixing
drum in which pre-processed coal and a solvent are mixed to form a
slurry; a catalyst supply unit that supplies a dispersed catalyst
to the mixing drum; a reactor that liquefies a coal slurry that
passes through the mixing drum; a gas supply unit that supplies a
cracking gas to the reactor; a separation unit that separates an
additive from a liquefied product that is generated in the reactor;
and a supply line that is connected between the separation unit and
the mixing drum to supply oil that is separated in the separation
unit as a solvent to the mixing drum.
13. The coke additive manufacturing apparatus of claim 12, wherein
the separation unit comprises: a separator that separates a gas
component in a liquefying process product, a filter device that is
connected with the separator to separate a liquid material and a
solid material, and a distiller that separates an additive by
distilling a liquid material that is separated in the filter device
and that is connected with the mixing drum through the supply line
to supply the additive and separated oil to the mixing drum.
14. The coke additive manufacturing apparatus of claim 13, wherein
the manufacturing apparatus further comprises a crusher that
crushes coal for coal pre-processing and a dryer that dries the
crushed coal.
15. The coke additive manufacturing apparatus of claim 12, wherein
the catalyst supply unit supplies a dispersed iron catalyst.
16. The coke additive manufacturing apparatus of claim 15, wherein
the gas supply unit supplies coke oven gas (COG) and/or liquefied
natural gas (LNG).
Description
TECHNICAL FIELD
[0001] The present invention relates to a method and apparatus for
manufacturing a coke additive that can improve strength of
coke.
BACKGROUND ART
[0002] In general, coke is produced through a coke production
process using coking coal. Coking coal that is used for producing
coke is classified into hard coking coal and semi-soft coking coal
according to a level of a coking property. For a stable operation
of a large blast furnace, use of high strength coke is required. In
order to produce high strength of coke, it is advantageous to use
hard coking coal having an excellent coking property or to use hard
coking coal in large quantities rather than semi-soft coking coal.
Accordingly, when producing coke, high quality and expensive hard
coking coal has been used in large quantities.
[0003] However, due to a rapid increase in demand for global
metallurgical coking coal and limited deposits of hard coking coal,
it is gradually becoming more difficult to secure hard coking coal
and thus a problem has occurred that a price thereof rapidly
increases. Therefore, in order to use non-coking coal such as low
quality and cheap subbituminous coal or lignite as coking coal,
technical development to produce high strength coke has been
actively performed.
[0004] For example, technology has been developed that produces a
quality enhancement agent for manufacturing coke through a solvent
extraction method that extracts a coking material by dissolving low
quality coking coal in an expensive supercritical solvent in a high
temperature and high pressure condition.
[0005] However, in a conventional structure, because it is required
to construct large-scale facilities, there is a drawback that an
excessive investment cost is required and expensive hydrogen should
be continuously supplied, and for this reason, because expensive
equipment such as hydrogenation equipment is required, there is a
problem that a production cost increases.
[0006] Further, conventionally, because oil is generally produced
from coal, an additive may not be produced in large quantities.
DISCLOSURE
Technical Problem
[0007] The present invention has been made in an effort to provide
a method and apparatus for manufacturing a coke additive that is
optimized for extraction of the coke additive.
[0008] The present invention has been made in an effort to further
provide a method and apparatus for manufacturing a coke additive
that can easily and effectively produce an additive for improving
coke strength through a coal liquefying step that is optimized for
extraction of the coke additive.
[0009] The present invention has been made in an effort to further
provide a method and apparatus for manufacturing a coke additive
that can manufacture an additive without construction of
large-scale equipment such as hydrogenation equipment.
[0010] The present invention has been made in an effort to further
provide a method and apparatus for manufacturing a coke additive
that can simplify a production process.
[0011] The present invention has been made in an effort to further
provide a method and apparatus for manufacturing a coke additive
that can manufacture a coke additive using low quality coal.
Technical Solution
[0012] An exemplary embodiment of the present invention provides a
method of manufacturing a coke additive, including: a coal
pre-processing step of dispersing coal in a solvent to form a
slurry; a step of introducing a dispersed iron catalyst while
pre-processing the coal; a coal liquefying step of liquefying the
coal slurry by reacting the coal slurry with a cracking gas; a step
of supplying coke oven gas (COG) and/or liquefied natural gas (LNG)
as a cracking gas in the coal liquefying step; a step of separating
an additive from a liquefied product; and a recycling step of
supplying liquid oil obtained in the separation step to the coal
pre-processing step and using the liquid oil as the solvent.
[0013] The coal pre-processing step may further include a step of
crushing the coal and a step of drying the crushed coal.
[0014] The coal may include lignite or subbituminous coal.
[0015] In the coal crushing step, the coal may be crushed to a size
of 60 mesh or less.
[0016] In the coal drying step, the coal may be dried to have a
moisture content of 20 wt % or less.
[0017] In the coal pre-processing step, the dried coal may be mixed
with the solvent in a weight ratio of 1/1 to 1/4 to form a
slurry.
[0018] The dispersed iron catalyst may be Fe.sub.2O.sub.3.
[0019] 0.5 to 3.0 parts by weight of the dispersed iron catalyst
may be injected for 100 parts by weight of the coal.
[0020] The coal liquefying step may be performed at a temperature
of 250 to 450.degree. C. and a pressure of 30 to 120 bar.
[0021] In the coal liquefying step, the cracking gas may be
supplied by being heated at a temperature of 300 to 600.degree.
C.
[0022] The separation process may include a separating step that
separates a gas component from a liquefied product, a filtration
step that separates a liquid material and a solid material, and a
fractional distillation step that separates an additive by
distilling the liquid material that is separated in the filtration
step, and in the recycling step, the additive and an oil that is
separated in the fractional distillation step may be supplied to
the coal pre-processing step.
[0023] The filtration step may be performed at a temperature of 120
to 400.degree. C.
[0024] The fractional distillation step may be performed at a
temperature of 200 to 350.degree. C.
[0025] Another embodiment of the present invention provides a coke
additive manufacturing apparatus including: a mixing drum in which
pre-processed coal and a solvent are mixed to form a slurry; a
catalyst supply unit that supplies a dispersed catalyst to the
mixing drum; a reactor that liquefies a coal slurry that passes
through the mixing drum; a gas supply unit that supplies a cracking
gas to the reactor; a separation unit that separates an additive
from a liquefied product that is generated in the reactor; and a
supply line that is connected between the separation unit and the
mixing drum to supply oil that is separated in the separation unit
as a solvent to the mixing drum.
[0026] The separation unit may include a separator that separates a
gas component from a liquefying process product, a filter device
that is connected with the separator to separate a liquid material
and a solid material, and a distiller that separates an additive by
distilling a separated liquid material in the filter device and
that is connected with the mixing drum through the supply line to
supply the additive and separated oil to the mixing drum.
[0027] The manufacturing apparatus may further include a crusher
that crushes coal for coal pre-processing and a dryer that dries
the crushed coal.
[0028] The catalyst supply unit may supply a dispersed iron
catalyst.
[0029] The gas supply unit may supply coke oven gas (COG) and/or
liquefied natural gas (LNG).
Advantageous Effects
[0030] According to the present implementation, an optimized
additive production process can be implemented.
[0031] In addition, by optimizing an additive production process, a
coke additive can be more economically and efficiently
produced.
[0032] Further, by simplifying a step, a cost can be reduced and an
additive production cost can be reduced.
[0033] Also, because it is unnecessary to construct hydrogen
production equipment, a production cost can be lowered.
DESCRIPTION OF THE DRAWINGS
[0034] FIG. 1 is a schematic diagram illustrating a coke additive
manufacturing apparatus according to the present exemplary
embodiment.
MODE FOR INVENTION
[0035] Technical terms used herein are used for only describing a
specific exemplary embodiment and are not intended to limit the
present invention. Singular forms used herein include plural forms
unless explicitly described to the contrary. A meaning of
"comprising" used in a specification embodies a specific
characteristic, area, integer, step, operation, element, and/or
component, and does not exclude the presence or addition of another
specific characteristic, area, integer, step, operation, element,
component, and/or group.
[0036] Hereinafter, an exemplary embodiment of the present
invention will be described in detail with reference to the
attached drawing such that the present invention can be easily put
into practice by those skilled in the art. As a person of ordinary
skill in the art can easily understand, the following exemplary
embodiment may be changed in various forms within the scope without
deviating from a concept and range of the present invention. As
those skilled in the art would realize, the described embodiment
may be modified in various different ways, all without departing
from the spirit or scope of the present invention.
[0037] FIG. 1 is a schematic diagram illustrating a coke additive
manufacturing apparatus according to the present exemplary
embodiment.
[0038] As shown in FIG. 1, a manufacturing apparatus of the present
exemplary embodiment includes a mixing drum 10 in which
pre-processed coal and a solvent are mixed to form a slurry, a
catalyst supply unit 20 that supplies a dispersed catalyst to the
mixing drum 10, a reactor 30 that liquefies the coal slurry that
passes through the mixing drum 10, a gas supply unit 32 that
supplies a cracking gas to the reactor 30, a separation unit 40
that separates an additive from a liquefied product that is
generated in the reactor 30, and a supply line 50 that is connected
between the separation unit 40 and the mixing drum 10 to supply an
oil that is separated from the separation unit as a solvent to the
mixing drum 10.
[0039] The manufacturing apparatus may further include a crusher 12
that crushes the coal for pre-processing of the coal and a dryer 14
that dries the crushed coal.
[0040] In the present exemplary embodiment, coal, which is a raw
material for producing an additive, may include low quality
non-coking coal such as lignite or subbituminous coal. The low
quality coal such as lignite or subbituminous coal has poor coking
properties such as cohesion and the like, but there are abundant
reserves thereof and it is inexpensive and thus when producing a
coke additive, a production cost can be lowered.
[0041] The mixing drum 10 mixes pre-processed coal and a solvent to
form a coal slurry.
[0042] In the present exemplary embodiment, as a solvent that is
injected into the mixing drum 10, oil remaining after finally
separating an additive through the separation unit 40 is used.
[0043] To this end, because the supply line 50 is connected between
the separation unit 40 and the mixing drum 10, after an additive is
separated, remained oil as a solvent is recirculated and supplied
to the mixing drum 10 through the supply line 50.
[0044] In this way, by directly supplying liquid oil that is
separated via the separation unit 40 to the mixing drum 10 and
reusing the liquid oil as a solvent, equipment can be simplified,
and by simplifying a step, an additive production cost can be
lowered.
[0045] The catalyst supply unit 20 is connected with the mixing
drum 10 to supply a dispersed iron catalyst. Accordingly, the
dispersed iron catalyst is evenly mixed with the coal and solvent
in the mixing drum 10.
[0046] In the present exemplary embodiment, the dispersed iron
catalyst may be Fe.sub.2O.sub.3. In this way, by injecting the
dispersed iron catalyst and mixing the dispersed iron catalyst in
the coal slurry, in a liquefaction reaction, reactivity may be
enhanced. Accordingly, even if COG or LNG is used as a cracking gas
in a liquefaction reaction, the dispersed iron catalyst may enhance
reactivity to induce a sufficient reaction effect for producing an
additive.
[0047] The coal slurry that is mixed in the mixing drum 10 is
transferred to the reactor 30 by a high pressure pump. In a step of
transferring the coal slurry from the mixing drum 10 to the reactor
30, by supplying heat to the coal slurry through a heater 16 that
is installed between the mixing drum 10 and the reactor 30, the
coal slurry is heated to a predetermined temperature.
[0048] The reactor 30 is sufficiently resistant to high temperature
and high pressure, has a reaction space therein, and liquefies the
coal slurry in a high temperature and high pressure condition. A
heater for supplying thermal energy to the reactor 30 may be
installed outside of the reactor 30, and an agitator may be
installed inside of the reactor 30. The gas supply unit 32 is
connected with one side of the reactor 30 to supply the cracking
gas to the reactor 30. In the present exemplary embodiment, the gas
supply unit 32 supplies coke oven gas (COG), liquefied natural gas
(LNG), or a combination thereof as a cracking gas.
[0049] In this way, by using the COG or the LNG as a cracking gas,
it is unnecessary for an apparatus of the present exemplary
embodiment to include conventional hydrogen production equipment.
As is known, the hydrogen production equipment is very complex
equipment, a construction cost thereof corresponds to about a
quarter of entire equipment cost, and an operation cost thereof is
very high. Therefore, in the present exemplary embodiment, because
hydrogen production equipment may not be constructed, an entire
factory size can be reduced and a production cost of an additive
can be greatly lowered.
[0050] The separation unit 40 includes a separator 42 that
separates a gas component from a liquefied product, a filter device
44 that is connected with the separator to separate a liquid
material and a solid material, and a distiller 46 that distills a
liquid material that is separated from the filter device to
separate a coke additive B.
[0051] The distiller 46 of the separation unit 40 is connected with
the mixing drum 10 through the supply line 50. Accordingly, oil
that is separated from the additive via the distiller 46 is
supplied to the mixing drum 10 through the supply line. As the
distiller 46, a fractional distiller that separates additives using
a difference of boiling points may be used.
[0052] In this way, this apparatus can finally produce the coke
additive B via the separation unit 40.
[0053] Hereinafter, an additive production process according to the
present exemplary embodiment will be described.
[0054] The additive production process includes a coal
pre-processing step of dispersing the coal in a solvent to form a
slurry, a step of introducing a dispersed iron catalyst while
pre-processing the coal, a coal liquefying step of liquefying a
coal slurry by reacting coal slurry with a cracking gas, a step of
supplying COG and/or LNG to the cracking gas in the coal liquefying
step, a separation step of separating an additive from a liquefied
product, and a recycling step of supplying a liquid oil that is
obtained in the separation step to the coal pre-processing step and
using the liquid oil as the solvent.
[0055] The coal pre-processing step is a step of pre-processing and
preparing coal, which is a raw material for producing an additive,
and in the coal pre-processing step, a step of crushing coal and
drying the crushed coal is performed.
[0056] The coal is a raw material that has a low coking property or
no coking property and is inexpensive semi-soft coking coal (or low
rank coal), and lignite or subbituminous coal may be used. Low
quality coal such as lignite and subbituminous coal is crushed
through a crusher. The coal may be crushed in a size of, for
example, 60 mesh or less.
[0057] Moisture is removed from the crushed coal via a drying step.
Coal moisture interferes with the mixing of the coal and the
solvent, and causes a reactor pressure to be unstable to
deteriorate reaction efficiency. In the present exemplary
embodiment, the coal is dried to have a moisture content of 20 wt %
or less through the coal drying step. When the moisture content of
the coal exceeds 20 wt %, process efficiency is deteriorated and an
additional waste gas processing process is required.
[0058] The crushed and dried coal is mixed with a solvent to form a
slurry. In the present exemplary embodiment, the dried coal and the
solvent are mixed in a weight ratio of 1/1 to 1/4.
[0059] When a ratio of coal to the solvent is larger than 1/1, a
quantity of the solvent is small and thus the coal slurry is not
well generated. Accordingly, a coal conversion rate in the reactor
is lowered. When the ratio of coal to the solvent is lower than
1/4, too much solvent is added and thus a viscosity of the coal
slurry is lowered, and throughput at each step increases and thus
equipment size needs to be increased. Accordingly, an apparatus
cost and a utility use amount increase and thus a cost problem
occurs.
[0060] Here, in the solvent, an additive may be finally separated
via an additive production step and the remaining oil may be
used.
[0061] A dispersed iron catalyst may be injected in the coal
pre-processing step.
[0062] In the present exemplary embodiment, the dispersed iron
catalyst may be Fe.sub.2O.sub.3. By introducing the dispersed iron
catalyst and mixing the dispersed iron catalyst with the coal
slurry, reactivity can be enhanced in a liquefaction reaction.
[0063] 0.5 to 3.0 parts by weight of the dispersed iron catalyst
may be injected for 100 parts by weight of the coal.
[0064] When the dispersed iron catalyst is injected at less than
the range, the dispersed iron catalyst cannot appropriately perform
a function as a catalyst, and when the dispersed iron catalyst
exceeds the range, it is difficult to recover the dispersed iron
catalyst and the excess catalyst has no further benefit.
[0065] Coal that is formed into the slurry via the step is
transferred to the reactor to perform a coal liquefying step. The
coal slurry is heated to a desired temperature via a heating step
in a transfer step to a liquefying step.
[0066] The coal liquefying step is a step of liquefying the coal
slurry at a sufficiently high temperature in the pre-processing
step. The coal slurry and the cracking gas are injected into the
reactor, and a liquefaction reaction is performed at a
predetermined temperature and pressure.
[0067] In the present exemplary embodiment, the coal liquefying
step may be performed in a temperature of 250 to 450.degree. C. and
a pressure of 30 to 120 bar. By adjusting a supply flow rate of the
cracking gas, the internal pressure of the reactor may be
controlled.
[0068] Because the inside of the reactor is formed in the
temperature and pressure range, in a mixture that is mixed with the
coal and the solvent, i.e., the coal slurry, a liquefaction
reaction is performed. In this case, by connecting a disconnected
ring between carbon atoms constituting the coal as well as pressure
adjustment within the reactor, the supplied cracking gas performs a
function of liquefying the coal.
[0069] In the coal liquefying step, when the temperature is lower
than 250.degree. C., coal is not melted and thus a liquefying
process is not performed, and when the temperature exceeds
450.degree. C., coking of the coal occurs and thus the coal is
solidly hardened to deteriorate a reaction.
[0070] Further, in the coal liquefying step, when the reaction
pressure is lower than 30 bar, due to a low pressure within the
reactor, a problem occurs that hydrogen is not donated to the coal.
When the pressure exceeds 120 bar, hydrogen is excessively donated
to the coal and thus a production amount of a coke additive which
is a final resulting material reduces and a production amount of an
undesired material such as oil increases.
[0071] In the coal liquefying step, as the cracking gas, COG, LNG,
or a mixed gas thereof may be supplied.
[0072] According to a step condition within the reactor, COG or LNG
may be selectively used or both COG and LNG may be used and
supplied into the reactor.
[0073] In this way, by using COG or LNG, in the coal liquefying
step, a production amount of liquefying oil reduces and a
production amount of an additive increases.
[0074] The cracking gas may be heated to a temperature of 300 to
600.degree. C. and supplied according to an internal temperature of
the reactor in which a coal liquefaction reaction is performed.
Accordingly, when injecting the cracking gas, a change of an
internal temperature of the reactor is minimized and thus
reactivity may be prevented from being deteriorated.
[0075] A product that is generated in the coal liquefying step may
be separated into a coke additive, which is a final target, through
the separation process.
[0076] In the present exemplary embodiment, the separation process
sequentially includes a separating step of separating a gas
component from a liquefying process product, a filtration step of
separating a liquid material and a solid material, and a fractional
distillation step of distilling the liquid material that is
separated in the filtration step and separating an additive from
the liquid material.
[0077] A product that is liquefied via the coal liquefying step
includes a solid residue, a liquid product, and a vapor product.
The liquid product may include a coke additive and oil, and the
vapor product may include a fuel gas, sulfur, and ammonia.
[0078] In the separating step, lightest gas components (C1 to C5,
H.sub.2S, NH.sub.3, and H.sub.2) among materials that are generated
through the coal liquefying step are separated from the product. In
the filtration step, the product is separated into a solid residue
and a liquid product.
[0079] In the fractional distillation step following the filtration
step, a liquid product that is separated in the filtration step is
distilled and a coke additive is finally separated and
obtained.
[0080] In the present exemplary embodiment, the filtration step may
be performed at a temperature of 120 to 400.degree. C.
[0081] A softening point of the coke additive is about 120.degree.
C. Therefore, in the filtration step, when the temperature is lower
than 120.degree. C., a coke additive may exist as a solid residue
and thus the solid residue and the coke additive are mixed, thereby
not separating only the coke additive. Accordingly, the filtration
step is performed at a temperature of 120.degree. C. or more in
consideration of a softening point of the coke additive.
[0082] Further, as described above, because the coal liquefying
step is performed at a temperature of 250 to 450.degree. C., an
initial product that is generated in the coal liquefying step
exists at a high temperature of 120 to 400.degree. C. unless it is
cooled. Therefore, when performing the filtration step immediately
after the coal liquefying step instead of additionally heating the
product in the filtration step, at a temperature of 120.degree. C.
or more using heat of the product, a filtration step may be
performed. Accordingly, in the present exemplary embodiment,
immediately after the coal liquefying step, before the temperature
of the product is lowered to under 120.degree. C., it is necessary
to perform the filtration step.
[0083] In the fractional distillation step, by distilling a liquid
product that is separated via the filtration step using the
distiller, the coke additive can be obtained.
[0084] As described above, the liquid product that is separated in
the filtration step includes the oil as well as the coke additive,
and may further include a fuel gas, sulfur, and ammonia according
to temperature.
[0085] In the fractional distillation step, commonly used
fractional distillation may be used.
[0086] In the present exemplary embodiment, the fractional
distillation step is operated in a vacuum state and may be
performed at a temperature of 200 to 350.degree. C. Because the
boiling point of oil in a liquid product is lower than 200 to
350.degree. C. under pressure, by separating and removing the oil
from the liquid product using a fractional distillation method, a
coke additive may be obtained. That is, in the fractional
distillation step, when heating a liquid product at a temperature
of 200 to 350.degree. C., oil is evaporated and only a coke
additive may be separated as a residue. Accordingly, by separating
the oil through the fractional distillation step, a coke additive
is finally obtained.
[0087] In the recycling step, by supplying oil that is obtained in
the separation process to the coal pre-processing step, the oil is
reused as a solvent of a coal slurry step.
[0088] In the present exemplary embodiment, in the recycling step,
oil that is obtained through the fractional distillation step is
supplied to the mixing drum of the coal pre-processing step. In
this way, by recycling the oil that is separated in the separation
process to the coal pre-processing step, a step can be
simplified.
[0089] While this invention has been described in connection with
what is presently considered to be practical exemplary embodiments,
it is to be understood that the invention is not limited to the
disclosed embodiments, but, on the contrary, is intended to cover
various modifications and equivalent arrangements included within
the spirit and scope of the appended claims.
* * * * *