US20170342326A1

US20170342326A1 - Method and apparatus for manufacturing cokes additive

Info

Publication number: US20170342326A1
Application number: US15/532,716
Authority: US
Inventors: Sang Hyun Park; Hee-Su Kim; Seung-jae Lee; Sangon LEE
Original assignee: Posco Co Ltd
Current assignee: Posco Holdings Inc
Priority date: 2014-12-05
Filing date: 2015-06-23
Publication date: 2017-11-30
Also published as: JP2018501346A; JP6461345B2; AU2015355919B2; WO2016088963A1; AU2015355919A1; CN107207967A

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.

Description

TECHNICAL FIELD

The present invention relates to a method and apparatus for manufacturing a coke additive that can improve strength of coke.

BACKGROUND ART

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.
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.
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.
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.
Further, conventionally, because oil is generally produced from coal, an additive may not be produced in large quantities.

DISCLOSURE

Technical Problem

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.
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.
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.
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.
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

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.
The coal pre-processing step may further include a step of crushing the coal and a step of drying the crushed coal.
The coal may include lignite or subbituminous coal.
In the coal crushing step, the coal may be crushed to a size of 60 mesh or less.
In the coal drying step, the coal may be dried to have a moisture content of 20 wt % or less.
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.
The dispersed iron catalyst may be Fe₂O₃.
0.5 to 3.0 parts by weight of the dispersed iron catalyst may be injected for 100 parts by weight of the coal.
The coal liquefying step may be performed at a temperature of 250 to 450° C. and a pressure of 30 to 120 bar.
In the coal liquefying step, the cracking gas may be supplied by being heated at a temperature of 300 to 600° C.
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.
The filtration step may be performed at a temperature of 120 to 400° C.
The fractional distillation step may be performed at a temperature of 200 to 350° C.
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.
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.
The manufacturing apparatus may further include a crusher that crushes coal for coal pre-processing and a dryer that dries the crushed coal.
The catalyst supply unit may supply a dispersed iron catalyst.
The gas supply unit may supply coke oven gas (COG) and/or liquefied natural gas (LNG).

Advantageous Effects

According to the present implementation, an optimized additive production process can be implemented.
In addition, by optimizing an additive production process, a coke additive can be more economically and efficiently produced.
Further, by simplifying a step, a cost can be reduced and an additive production cost can be reduced.
Also, because it is unnecessary to construct hydrogen production equipment, a production cost can be lowered.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram illustrating a coke additive manufacturing apparatus according to the present exemplary embodiment.

MODE FOR INVENTION

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.
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.
FIG. 1 is a schematic diagram illustrating a coke additive manufacturing apparatus according to the present exemplary embodiment.
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.
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.
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.
The mixing drum 10 mixes pre-processed coal and a solvent to form a coal slurry.
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.
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.
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.
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.
In the present exemplary embodiment, the dispersed iron catalyst may be Fe₂O₃. 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.
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.
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.
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.
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.
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.
In this way, this apparatus can finally produce the coke additive B via the separation unit 40.
Hereinafter, an additive production process according to the present exemplary embodiment will be described.
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.
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.
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.
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.
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.
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.
Here, in the solvent, an additive may be finally separated via an additive production step and the remaining oil may be used.
A dispersed iron catalyst may be injected in the coal pre-processing step.
In the present exemplary embodiment, the dispersed iron catalyst may be Fe₂O₃. By introducing the dispersed iron catalyst and mixing the dispersed iron catalyst with the coal slurry, reactivity can be enhanced in a liquefaction reaction.
0.5 to 3.0 parts by weight of the dispersed iron catalyst may be injected for 100 parts by weight of the coal.
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.
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.
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.
In the present exemplary embodiment, the coal liquefying step may be performed in a temperature of 250 to 450° 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.
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.
In the coal liquefying step, when the temperature is lower than 250° C., coal is not melted and thus a liquefying process is not performed, and when the temperature exceeds 450° C., coking of the coal occurs and thus the coal is solidly hardened to deteriorate a reaction.
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.
In the coal liquefying step, as the cracking gas, COG, LNG, or a mixed gas thereof may be supplied.
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.
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.
The cracking gas may be heated to a temperature of 300 to 600° 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.
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.
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.
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.
In the separating step, lightest gas components (C1 to C5, H₂S, NH₃, and H₂) 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.
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.
In the present exemplary embodiment, the filtration step may be performed at a temperature of 120 to 400° C.
A softening point of the coke additive is about 120° C. Therefore, in the filtration step, when the temperature is lower than 120° 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° C. or more in consideration of a softening point of the coke additive.
Further, as described above, because the coal liquefying step is performed at a temperature of 250 to 450° C., an initial product that is generated in the coal liquefying step exists at a high temperature of 120 to 400° 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° 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° C., it is necessary to perform the filtration step.
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.
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.
In the fractional distillation step, commonly used fractional distillation may be used.
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° C. Because the boiling point of oil in a liquid product is lower than 200 to 350° 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° 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.
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.
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.
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.

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 Fe₂O₃.

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° C.

7. The method of claim 6, wherein the fractional distillation step is performed at a temperature of 200 to 350° 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° 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° 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).