Title of Invention	A PROCESS TO PRODUCE LOW ASH CLEAN COAL FROM HIGH ASH COALS FOR VARIOUS METALLURGICAL APPLICATIONS
Abstract	A process to produce low ash coals, characterized in that ash content less than 4%, from high ash coal comprising steps of: (i)mixing of coal thoroughly with solvent such as N-methyl -2-pyrrolidone (NMP) and co-solvent such Monoethanolamine (MEA) to produce coal-solvent mixture in a coal-solvent feed tank(i); (ii) extracting the coal-solvent mixture an extractor (2); (iii) filtering the extracted coal-solvent mixture through first filtering unit (3) to obtain a coarser fraction (+0.025mm) and a finer fraction (-0.025 mm); (iv) evoporating the finer fraction in a evaporation unit (4) to recover 80-85 % solvent; (v) precipitating coal from concentrated coal-solvent mixture in a precipitation tank (5); (vi) filtering the precipitating coal, as secured in step (v), to obtain clean coal having less than 4% ash content.

Title of Invention

A PROCESS TO PRODUCE LOW ASH CLEAN COAL FROM HIGH ASH COALS FOR VARIOUS METALLURGICAL APPLICATIONS

Abstract

A process to produce low ash coals, characterized in that ash content less than 4%, from high ash coal comprising steps of: (i)mixing of coal thoroughly with solvent such as N-methyl -2-pyrrolidone (NMP) and co-solvent such Monoethanolamine (MEA) to produce coal-solvent mixture in a coal-solvent feed tank(i); (ii) extracting the coal-solvent mixture an extractor (2); (iii) filtering the extracted coal-solvent mixture through first filtering unit (3) to obtain a coarser fraction (+0.025mm) and a finer fraction (-0.025 mm); (iv) evoporating the finer fraction in a evaporation unit (4) to recover 80-85 % solvent; (v) precipitating coal from concentrated coal-solvent mixture in a precipitation tank (5); (vi) filtering the precipitating coal, as secured in step (v), to obtain clean coal having less than 4% ash content.

Full Text	FIELD OF THE INVENTION The invention relates to a process to produce low ash clean coal from high ash coals for various metallurgical applications. BACKGROUND OF THE INVENTION Concept of chemical benefication comes from' the limitation of physical beneficiation processes. Broadly, chemical beneficiation is possible by chemical leaching of mineral mater present in coal or, dissolving organic matter of coal in various organic solvents. As coal is heterogeneous mixture of organic and inorganic constituents, solvolysis of coal varies with its constituents, maturity and structural characteristics. Main advantage of this process are i) ease of recovery of solvent in the main process stream, ii) solvolytic efficiency of recovered solvents as that of fresh solvent, iii) 95-98% recovery of the solvent, iv) improved coking properties of clean coal, and v) availability of industrial organic solvents. However, the operating cost of this process is high because of high cost of solvents and energy requirement in the process. There is an attempt to make this process techno-economic through improving the yield to 70-80%. However, further research may be required to make the process economically viable through reducing the cost of solvent recovery. Recovery of clean coal and its ash content depend on various operating parameters and feed characteristics like faster and convenient filtration of refluxed solution at different size, solvent and co-solvent of choice, coal source (feed characteristics), particle size, coal-solvent ratio, extraction time, extraction Recovery of clean coal and its ash content depend on various operating parameters and feed characteristics like faster and convenient filtration of refluxed solution at different size, solvent and co-solvent of choice, coal source (feed characteristics), particle size, coal-solvent ratio, extraction time, extraction temperature, etc. This may thus offer the room for the trade off between the yield and the ash contents desired in the clean coal obtained by this process. Since the mineral matter (non-combustible)in Indian coals (Gondwana coals) is very finely disseminated in the organic mass,it is really very difficult to remove this by conventional physical coal washing techniques. High percentage of near gravity material in coal makes the scope of gravity process limited. This indicates that chemical treatment may be the right approach to overcome the limitation of physical beneficiation methods. A lot of literature is available on chemical beneficiation techniques that employ highly corrosive chemicals (mostly acids and alkalis). Recovery or regeneration of these chemicals is very important to make this technology viable. A parallel approach towards lowering ash could be recovering the premium organic matter from coal by solvent refining. Literature reveals that most of the research work on this subject was carried out with an objective to produce ultra clean coal or super clean coal with ash content less than 0.2% for various high tech end uses. This conventional solvent refining process does not serve the objective of low ash coal requirement of steel industries because of mainly low recovery which makes the process uneconomic especially when such an ultra coal is not absolutely desired at the cost of restricting to low yields. Organo refining or, solvent-refining, or, solvent extraction of coal is a well established technology. Abundant literature is available on the subject. However, the primary objective in most of those cases is to provide a process to produce ultra coal or super clean coal with ash contains less than 0.2%. The same process has been tried in our laboratory to produce suitable coal for coke making from medium coking coal. -0.5 mm Run-of-mine (ROM) coal from Washeries has been used as parent coal for organo-refining process. The ash content of this coal was 22%. Exploratory ,study revealed that it is possible to extract only 30% of parent coal through this process of extraction of coal under reflux conditions at atmospheric pressure. The coal so expected contains 1% ash. Losing 70% of the parent coal (with having only 12% ash) as rejects is not acceptable. The solvent extraction of coal process involves mainly the mass transfer operations. This involves the diffusion of solvents in the solid coal matrix which results in the swelling of coal. Then as the extraction proceeds, desorption of solvent containing the extracted molecules from the swollen coal matrix results in the extraction of coal molecules. It has been observed that there is a synergistic extraction enhancement of coal by using a suitable co-solvent which may aid the swelling of coal matrix for the enhanced extraction. Solvent extraction proceeds with the shrinking of cores of the coal particles as the extraction progresses. This shrinking cores result in the demineralization of coal particles. This may thus afford the chemical designing of the process of the solvent extraction of coal in such a way that the ash reduction in coal particles may be tailored to different ash levels. Since the solvent extraction leaches or cuts down the coal particles to different ash levels, therefore a suitable selection of the separation aid may help in obtaining the extracts of the coal macerals i.e., super clean coal having ash contents of different cuts or extent. Therefore there is a need to find out a convenient co-solvent for the N-methyl-2-pyrrolidone (NMP) to obtain a designer solvent. There is also a need to find out the filter of a specific pore size i.e., mesh size to obtain a coal extract having ash contents in the suitable range for coke making. OBJECTS OF THE INVENTION It is therefore an object of the invention to propose a process to produce low ash clean coal from high ash coal which eliminates the disadvantages of prior art. Another object of the invention is to propose a process to produce low ash clean coal from high ash coal which is for suitable industrial extraction of coal by using a combination of economic and environment friendly solvent-cosolvent . A still further object of the invention is to propose a process to produce low ash clean coal from high ash coal which ensures high recovery with low ash content. A still another object of the invention is to propose a process to produce low ash clean coal from high ash coal which provides faster filtration. A still another object of the invention is to propose a process to produce low ash clean coal from high ash coal which provides washing mechanism. BRIEF DESCRIPTION OF THE ACCOMPAYING DRAWINGS Fig 1- shows process flow sheet for high recovery of low ash coal through organo-refining SUMMARY OF INVENTION A process to produce low ash coals, characterized in that ash content less than 4% from high ash coal comprising steps of (i) mixing of coal thoroughly with solvent such as N-methyl -2-pyrrolidone (NMP) and co-solvent such Monoethanolamine (MEA) to produce coal-solvent mixture in a coal-solvent feed tank(l); (ii) extracting the coal-solvent mixture an extractor (2); (iii) filtering the extracted Coal-solvent mixture through first filtering unit (3) to obtain a coarser fraction (+0.025mm) and a finer fraction (-0.025 mm); (iv) Evoporating the finer fraction in a evaporation unit (4) to recover 80-85 % solvent; (v) precipitating coal from concentrated coal-solvent mixture in a precipitation tank (5) and (vi) filtering the precipitating coal, as secured in step (v) to obtain clean coal having less than 4% ash content. Accordingly to a second aspect of the invention, there is provided a device or carrying -out the innovative process. The device essentially comprises an extractor (2) to receive coal slurry from a coal-solvent feed tank and for extraction of the same. A Rotary Drum filter (3) is connected to the extractor (2) which on receiving the extracted coal-solvent mixture cut the mixture into two fractions. The finer fraction is fed from the first filter to an evaporation unit (4) for solvent recovery. A precipitation tank (5) is flowably connected to the evaporation unit (4). The precipitated coal is then separated in a second rotary drum filter (6). The solvent is recovered through a distillation unit (9), wherein the bi-product in the distillation unit which is steam is used as heat source for the extractor (2). DETAILS DESCRIPTION OF THE INVENTION A Suitable solvent-co-solvent combination has been identified for convenient, environmental friendly and economical industrial extraction operation. N-methyl-2-pyrrolidone (NMP) with a small amount of Monoethanolamine (MEA) is found as the best suitable solvent for the present. The ration of NMP and MEA may vary from 14:1 to 24:1 and the coal (g) to solvents (ml) ration may vary from 1:15 to 1:25. The coal sample is refluxed with NMP and a small amount of MEA for 1.5 h at atmospheric pressure. Then the refluxed mixture using 500 stainless steel BSS mesh (0.025 mm) cloth is filtered. This arrangement allowed coarser and faster filtration at 0.025 mm size, in comparison to that observed by using Whatman filter paper. Therefore, increase in yield of clean coal and simultaneously increase in ash content of clean coal, have been clearly established. However, this arrangement is found to be advantageous to produce high yield coal with low ash content (5-8%) through a faster filtration process. Comparison of the extraction yields obtained by using NMP alone (32%) with that obtained by using a convenient co-solvent i.e., MEA (50.1%) showed the , synergism of using MEA as a co-solvent. This invention thus enables producing . low^n^ a relatively faster filtration. The extraction yields on dry mineral matter basis will be still higher. A device has been developed for bench scale operation which is shown in Fig.l. The device consists of six units namely, (i) an Extractor(2), (ii) a first filter (3) (separation size 500 mesh), (iii) an Evaporator column (4), (iv) a Precipitation tank (5), (v) a second filter (6) (for complete solid-liquid separation) and (vi) a Distillation column (9). .,^_TO_^__._ , „. Coal, solvent and co-solvent are mixed thoroughly in coal-solvent feed tank (1). Coal slurry is then pumped into the extractor (2). A temperature around 170°C is achieved in the extractor (2) slowly. Residence time in the extractor (2) may vary from 15 mins to 2 h and i.e. dictated by the techno economics of the process and its specific requirement. Extracted coal-solvent mixture is then separated through a first filter (3) or any separation unit which may cut the mixture in two fractions: coarser fraction (+0.025 mm) and finer fraction (-0.025 mm). Coarser fraction contains high ash and is called as residue. The finer fraction or filtered extract is then fed to an evaporator unit (4). Maximum 80-85% solvent recovery may be allowed through evaporator unit (4). The, concentrated coal-solvent mixture is flushed in a precipitation tank (5). As NMP-MEA solvents are soluble in water, extracted coal gets separated from the solution phase and gets precipitated. This precipitated coal is separated through a second filter (6). Thus obtained clean coal contains less than 4% ash. The filtrate consists of solvent-water solution and solvent is recovered through a second distillation unit (9). The secondary product of the distillation unit (9) is steam, which may be used as a heat source in the extractor (2) at a high pressure. It is possible to recover around 98% of solvent-through the evaporator and distillation units (4,9). An alternative route has also been explored for recovering low ash clean coal. The process is same as described till we separate the extract into two cuts. In this alternate route, the finer cut is fed into precipitation tank (5) without concentrating. This allows coal to precipitate directly. The precipitated coal is separated through a second rotary drum filter (6) (as described earlier). The filtrate consisting solvent and water is separated through a distillation unit (9). Thus, this alternate route eliminates the first distillation unit from the process flow sheet. This alternate route also has potential scope from industrial application point of view. WE CLAIM: 1. A process to produce low ash coals characterized in that ash content less than 4%, from high ash coal comprising steps of:- (i) mixing of coal thoroughly with solvent such as N-methyl -2-pyrrolidone (NMP) and co-solvent such as Monoethanolamine (MEA) to produce coal -solvent mixture in a coal-solvent feed tank(l); (ii) extracting the coal-solvent mixture an extractor (2); (iii) filtering the extracted Coal-solvent mixture through first filtering unit (3) to obtain a coarser fraction (+0.025mm) and a finer fraction (-0.025 mm); (iv) evoporating the finer fraction in a evaporation unit (4) to recover 80-85 % solvent; (v) precipitating coal from concentrated coal-solvent mixture in a precipitation tank (5); (vi) filtering the precipitating coal, as secured in step (v), to obtain clean coal having less than 4% ash content. 2. The process, as claimed in Claim 1, wherein NMP and MEA are added in the ration, by volume, of 14:1 to 24:1. 3. The process, window as claimed in Claim 1, where coal (9) to solvents (ml) ration vary from 1:15 to 1:25. 4. The process, as claimed in Claim 1 wherein the coal is refluxed with NMP and MEA for 1.5 hour at atmospheric pressure. 5. The process window, as claimed in Claim 1, where Alteration is carried out in first Alteration unit (3) using 500 stainless steel BSS mesh (0.025 mm) cloth. 6. The process, as claimed in Claim 1 wherein solvent recovery is 80-85% during evaporation . 7. The process to produce low ash clean coal from high ash coal as substantially described and illustrated herein with accompanying drawing. ABSTARCT A PROCESS TO PRODUCE LOW ASH CLEAN COAL FROM HIGH ASH COALS FOR VARIOUS METALLURGICAL APPLICATIONS A process to produce low ash coals, characterized in that ash content less than 4%, from high ash coal comprising steps of: (i)mixing of coal thoroughly with solvent such as N-methyl -2-pyrrolidone (NMP) and co-solvent such Monoethanolamine (MEA) to produce coal-solvent mixture in a coal-solvent feed tank(i); (ii) extracting the coal-solvent mixture an extractor (2); (iii) filtering the extracted coal-solvent mixture through first filtering unit (3) to obtain a coarser fraction (+0.025mm) and a finer fraction (-0.025 mm); (iv) evoporating the finer fraction in a evaporation unit (4) to recover 80-85 % solvent; (v) precipitating coal from concentrated coal-solvent mixture in a precipitation tank (5); (vi) filtering the precipitating coal, as secured in step (v), to obtain clean coal having less than 4% ash content.

Full Text

FIELD OF THE INVENTION
The invention relates to a process to produce low ash clean coal from high ash
coals for various metallurgical applications.
BACKGROUND OF THE INVENTION
Concept of chemical benefication comes from' the limitation of physical beneficiation processes. Broadly, chemical beneficiation is possible by chemical leaching of mineral mater present in coal or, dissolving organic matter of coal in various organic solvents. As coal is heterogeneous mixture of organic and inorganic constituents, solvolysis of coal varies with its constituents, maturity and structural characteristics. Main advantage of this process are i) ease of recovery of solvent in the main process stream, ii) solvolytic efficiency of recovered solvents as that of fresh solvent, iii) 95-98% recovery of the solvent, iv) improved coking properties of clean coal, and v) availability of industrial organic solvents. However, the operating cost of this process is high because of high cost of solvents and energy requirement in the process. There is an attempt to make this process techno-economic through improving the yield to 70-80%. However, further research may be required to make the process economically viable through reducing the cost of solvent recovery.
Recovery of clean coal and its ash content depend on various operating
parameters and feed characteristics like faster and convenient filtration of
refluxed solution at different size, solvent and co-solvent of choice, coal source
(feed characteristics), particle size, coal-solvent ratio, extraction time, extraction

Recovery of clean coal and its ash content depend on various operating parameters and feed characteristics like faster and convenient filtration of refluxed solution at different size, solvent and co-solvent of choice, coal source (feed characteristics), particle size, coal-solvent ratio, extraction time, extraction temperature, etc. This may thus offer the room for the trade off between the yield and the ash contents desired in the clean coal obtained by this process.
Since the mineral matter (non-combustible)in Indian coals (Gondwana coals) is
very finely disseminated in the organic mass,it is really very difficult to remove
this by conventional physical coal washing techniques. High percentage of near
gravity material in coal makes the scope of gravity process limited. This indicates
that chemical treatment may be the right approach to overcome the limitation of
physical beneficiation methods. A lot of literature is available on chemical
beneficiation techniques that employ highly corrosive chemicals (mostly acids
and alkalis). Recovery or regeneration of these chemicals is very important to
make this technology viable. A parallel approach towards lowering ash could be
recovering the premium organic matter from coal by solvent refining. Literature
reveals that most of the research work on this subject was carried out with an
objective to produce ultra clean coal or super clean coal with ash content less
than 0.2% for various high tech end uses. This conventional solvent refining
process does not serve the objective of low ash coal requirement of steel
industries because of mainly low recovery which makes the process uneconomic
especially when such an ultra coal is not absolutely desired at the cost of
restricting to low yields.
Organo refining or, solvent-refining, or, solvent extraction of coal is a well established technology. Abundant literature is available on the subject. However, the primary objective in most of those cases is to provide a process to produce ultra coal or super clean coal with ash contains less than 0.2%. The same process has been tried in our laboratory to produce suitable coal for coke making from medium coking coal. -0.5 mm Run-of-mine (ROM) coal from Washeries has

been used as parent coal for organo-refining process. The ash content of this coal was 22%. Exploratory ,study revealed that it is possible to extract only 30% of parent coal through this process of extraction of coal under reflux conditions at atmospheric pressure. The coal so expected contains 1% ash. Losing 70% of the parent coal (with having only 12% ash) as rejects is not acceptable.
The solvent extraction of coal process involves mainly the mass transfer
operations. This involves the diffusion of solvents in the solid coal matrix which
results in the swelling of coal. Then as the extraction proceeds, desorption of
solvent containing the extracted molecules from the swollen coal matrix results in
the extraction of coal molecules. It has been observed that there is a synergistic
extraction enhancement of coal by using a suitable co-solvent which may aid the
swelling of coal matrix for the enhanced extraction. Solvent extraction proceeds
with the shrinking of cores of the coal particles as the extraction progresses. This
shrinking cores result in the demineralization of coal particles. This may thus
afford the chemical designing of the process of the solvent extraction of coal in
such a way that the ash reduction in coal particles may be tailored to different
ash levels. Since the solvent extraction leaches or cuts down the coal particles to
different ash levels, therefore a suitable selection of the separation aid may help
in obtaining the extracts of the coal macerals i.e., super clean coal having ash
contents of different cuts or extent. Therefore there is a need to find out a
convenient co-solvent for the N-methyl-2-pyrrolidone (NMP) to obtain a designer
solvent. There is also a need to find out the filter of a specific pore size i.e.,
mesh size to obtain a coal extract having ash contents in the suitable range for
coke making.
OBJECTS OF THE INVENTION
It is therefore an object of the invention to propose a process to produce low ash clean coal from high ash coal which eliminates the disadvantages of prior art.

Another object of the invention is to propose a process to produce low ash clean coal from high ash coal which is for suitable industrial extraction of coal by using a combination of economic and environment friendly solvent-cosolvent .
A still further object of the invention is to propose a process to produce low ash clean coal from high ash coal which ensures high recovery with low ash content.
A still another object of the invention is to propose a process to produce low ash clean coal from high ash coal which provides faster filtration.
A still another object of the invention is to propose a process to produce low ash clean coal from high ash coal which provides washing mechanism.
BRIEF DESCRIPTION OF THE ACCOMPAYING DRAWINGS
Fig 1- shows process flow sheet for high recovery of low ash coal through
organo-refining
SUMMARY OF INVENTION
A process to produce low ash coals, characterized in that ash content less than 4% from high ash coal comprising steps of (i) mixing of coal thoroughly with solvent such as N-methyl -2-pyrrolidone (NMP) and co-solvent such Monoethanolamine (MEA) to produce coal-solvent mixture in a coal-solvent feed tank(l); (ii) extracting the coal-solvent mixture an extractor (2); (iii) filtering the extracted Coal-solvent mixture through first filtering unit (3) to obtain a coarser fraction (+0.025mm) and a finer fraction (-0.025 mm); (iv) Evoporating the finer fraction in a evaporation unit (4) to recover 80-85 %

solvent; (v) precipitating coal from concentrated coal-solvent mixture in a precipitation tank (5) and (vi) filtering the precipitating coal, as secured in step (v) to obtain clean coal having less than 4% ash content.
Accordingly to a second aspect of the invention, there is provided a device or carrying -out the innovative process. The device essentially comprises an extractor (2) to receive coal slurry from a coal-solvent feed tank and for extraction of the same. A Rotary Drum filter (3) is connected to the extractor (2) which on receiving the extracted coal-solvent mixture cut the mixture into two fractions. The finer fraction is fed from the first filter to an evaporation unit (4) for solvent recovery. A precipitation tank (5) is flowably connected to the evaporation unit (4). The precipitated coal is then separated in a second rotary drum filter (6). The solvent is recovered through a distillation unit (9), wherein the bi-product in the distillation unit which is steam is used as heat source for the extractor (2).
DETAILS DESCRIPTION OF THE INVENTION
A Suitable solvent-co-solvent combination has been identified for convenient, environmental friendly and economical industrial extraction operation. N-methyl-2-pyrrolidone (NMP) with a small amount of Monoethanolamine (MEA) is found as the best suitable solvent for the present. The ration of NMP and MEA may vary from 14:1 to 24:1 and the coal (g) to solvents (ml) ration may vary from 1:15 to 1:25.
The coal sample is refluxed with NMP and a small amount of MEA for 1.5 h at atmospheric pressure. Then the refluxed mixture using 500 stainless steel BSS

mesh (0.025 mm) cloth is filtered. This arrangement allowed coarser and faster filtration at 0.025 mm size, in comparison to that observed by using Whatman filter paper. Therefore, increase in yield of clean coal and simultaneously increase in ash content of clean coal, have been clearly established. However, this arrangement is found to be advantageous to produce high yield coal with low ash content (5-8%) through a faster filtration process.
Comparison of the extraction yields obtained by using NMP alone (32%) with
that obtained by using a convenient co-solvent i.e., MEA (50.1%) showed the , synergism of using MEA as a co-solvent. This invention thus enables producing . low^n^ a relatively faster filtration. The extraction yields on dry mineral matter basis will
be still higher.
A device has been developed for bench scale operation which is shown in Fig.l.
The device consists of six units namely, (i) an Extractor(2), (ii) a first filter (3)
(separation size 500 mesh), (iii) an Evaporator column (4), (iv) a Precipitation
tank (5), (v) a second filter (6) (for complete solid-liquid separation) and (vi) a
Distillation column (9). .,^_TO_^__._ , „.
Coal, solvent and co-solvent are mixed thoroughly in coal-solvent feed tank (1). Coal slurry is then pumped into the extractor (2). A temperature around 170°C is achieved in the extractor (2) slowly. Residence time in the extractor (2) may vary from 15 mins to 2 h and i.e. dictated by the techno economics of the process and its specific requirement.
Extracted coal-solvent mixture is then separated through a first filter (3) or any separation unit which may cut the mixture in two fractions: coarser fraction (+0.025 mm) and finer fraction (-0.025 mm). Coarser fraction contains high ash and is called as residue. The finer fraction or filtered extract is then fed to an

evaporator unit (4). Maximum 80-85% solvent recovery may be allowed through evaporator unit (4). The, concentrated coal-solvent mixture is flushed in a precipitation tank (5). As NMP-MEA solvents are soluble in water, extracted coal gets separated from the solution phase and gets precipitated. This precipitated coal is separated through a second filter (6). Thus obtained clean coal contains less than 4% ash. The filtrate consists of solvent-water solution and solvent is recovered through a second distillation unit (9). The secondary product of the distillation unit (9) is steam, which may be used as a heat source in the extractor (2) at a high pressure. It is possible to recover around 98% of solvent-through the evaporator and distillation units (4,9).
An alternative route has also been explored for recovering low ash clean coal. The process is same as described till we separate the extract into two cuts. In this alternate route, the finer cut is fed into precipitation tank (5) without concentrating. This allows coal to precipitate directly. The precipitated coal is separated through a second rotary drum filter (6) (as described earlier). The filtrate consisting solvent and water is separated through a distillation unit (9). Thus, this alternate route eliminates the first distillation unit from the process flow sheet. This alternate route also has potential scope from industrial application point of view.

WE CLAIM:
1. A process to produce low ash coals characterized in that ash content less than 4%, from high ash coal comprising steps of:-
(i) mixing of coal thoroughly with solvent such as N-methyl -2-pyrrolidone (NMP) and co-solvent such as Monoethanolamine (MEA) to produce coal -solvent mixture in a coal-solvent feed tank(l);
(ii) extracting the coal-solvent mixture an extractor (2);
(iii) filtering the extracted Coal-solvent mixture through first filtering unit (3) to obtain a coarser fraction (+0.025mm) and a finer fraction (-0.025 mm);
(iv) evoporating the finer fraction in a evaporation unit (4) to recover 80-85 % solvent;
(v) precipitating coal from concentrated coal-solvent mixture in a precipitation tank (5);
(vi) filtering the precipitating coal, as secured in step (v), to obtain clean coal
having less than 4% ash content.

2. The process, as claimed in Claim 1, wherein NMP and MEA are added in the ration, by volume, of 14:1 to 24:1.
3. The process, window as claimed in Claim 1, where coal (9) to solvents (ml) ration vary from 1:15 to 1:25.
4. The process, as claimed in Claim 1 wherein the coal is refluxed with NMP and MEA for 1.5 hour at atmospheric pressure.

5. The process window, as claimed in Claim 1, where Alteration is carried out in first Alteration unit (3) using 500 stainless steel BSS mesh (0.025 mm) cloth.
6. The process, as claimed in Claim 1 wherein solvent recovery is 80-85% during evaporation .
7. The process to produce low ash clean coal from high ash coal as substantially described and illustrated herein with accompanying drawing.

ABSTARCT

A PROCESS TO PRODUCE LOW ASH CLEAN COAL FROM HIGH ASH COALS FOR VARIOUS METALLURGICAL APPLICATIONS
A process to produce low ash coals, characterized in that ash content less than 4%, from high ash coal comprising steps of: (i)mixing of coal thoroughly with solvent such as N-methyl -2-pyrrolidone (NMP) and co-solvent such Monoethanolamine (MEA) to produce coal-solvent mixture in a coal-solvent feed tank(i); (ii) extracting the coal-solvent mixture an extractor (2); (iii) filtering the extracted coal-solvent mixture through first filtering unit (3) to obtain a coarser fraction (+0.025mm) and a finer fraction (-0.025 mm); (iv) evoporating the finer fraction in a evaporation unit (4) to recover 80-85 % solvent; (v) precipitating coal from concentrated coal-solvent mixture in a precipitation tank (5); (vi) filtering the precipitating coal, as secured in step (v), to obtain clean coal having less than 4% ash content.

Documents:

1336-KOL-2008-(13-07-2012)-CORRESPONDENCE.pdf

1336-KOL-2008-(20-01-2012)-ABSTRACT.pdf

1336-KOL-2008-(20-01-2012)-AMANDED CLAIMS.pdf

1336-KOL-2008-(20-01-2012)-CORRESPONDENCE.pdf

1336-KOL-2008-(20-01-2012)-DESCRIPTION (COMPLETE).pdf

1336-KOL-2008-(20-01-2012)-DRAWINGS.pdf

1336-KOL-2008-(20-01-2012)-FORM 1.pdf

1336-KOL-2008-(20-01-2012)-FORM 2.pdf

1336-KOL-2008-(20-01-2012)-FORM 3.pdf

1336-KOL-2008-(20-01-2012)-OTHERS.pdf

1336-kol-2008-abstarct.pdf

1336-kol-2008-claims.pdf

1336-KOL-2008-CORRESPONDENCE 1.1.pdf

1336-KOL-2008-CORRESPONDENCE 1.2.pdf

1336-KOL-2008-CORRESPONDENCE-1.3.pdf

1336-kol-2008-correspondence.pdf

1336-kol-2008-description (complete).pdf

1336-kol-2008-drawings.pdf

1336-KOL-2008-EXAMINATION REPORT.pdf

1336-KOL-2008-FORM 1 1.1.pdf

1336-KOL-2008-FORM 1.1.pdf

1336-kol-2008-form 1.pdf

1336-KOL-2008-FORM 13-1.1.pdf

1336-KOL-2008-FORM 13.pdf

1336-KOL-2008-FORM 18-1.1.pdf

1336-kol-2008-form 18.pdf

1336-kol-2008-form 2.pdf

1336-kol-2008-form 3.pdf

1336-KOL-2008-GPA-1.1.pdf

1336-kol-2008-gpa.pdf

1336-KOL-2008-GRANTED-ABSTRACT.pdf

1336-KOL-2008-GRANTED-CLAIMS.pdf

1336-KOL-2008-GRANTED-DESCRIPTION (COMPLETE).pdf

1336-KOL-2008-GRANTED-DRAWINGS.pdf

1336-KOL-2008-GRANTED-FORM 1.pdf

1336-KOL-2008-GRANTED-FORM 2.pdf

1336-KOL-2008-GRANTED-SPECIFICATION.pdf

1336-KOL-2008-OTHERS 1.1.pdf

1336-KOL-2008-OTHERS-1.1.pdf

1336-KOL-2008-REPLY TO EXAMINATION REPORT.pdf

1336-kol-2008-specification.pdf

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Patent Number

253307

Indian Patent Application Number

1336/KOL/2008

PG Journal Number

28/2012

Publication Date

13-Jul-2012

Grant Date

11-Jul-2012

Date of Filing

06-Aug-2008

Name of Patentee

TATA STEEL LIMITED

Applicant Address

JAMSHEDPUR 831001, INDIA,

Inventors:

#	Inventor's Name	Inventor's Address
1	MR. VIMAL KUMAR CHANDALIYA	TATA STEEL LIMITED RESEARCH AND DEVELOPMENT AND SCIENTIFIC SERVICES DIVISION, JAMSHEDPUR 831 001
2	MR. PRADIP KUMAR BANERJEE	TATA STEEL LIMITED RESEARCH AND DEVELOPMENT AND SCIENTIFIC SERVICES DIVISION, JAMSHEDPUR 831 001
3	MR. PINAKPANI BISWAS	TATA STEEL LIMITED RESEARCH AND DEVELOPMENT AND SCIENTIFIC SERVICES DIVISION, JAMSHEDPUR 831 001

PCT International Classification Number

C10L5/06

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA