CA1117884A - In-line method for the beneficiation of coal and the formation of a coal-in-oil combustible fuel therefrom - Google Patents
In-line method for the beneficiation of coal and the formation of a coal-in-oil combustible fuel therefromInfo
- Publication number
- CA1117884A CA1117884A CA000340749A CA340749A CA1117884A CA 1117884 A CA1117884 A CA 1117884A CA 000340749 A CA000340749 A CA 000340749A CA 340749 A CA340749 A CA 340749A CA 1117884 A CA1117884 A CA 1117884A
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- oil
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-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B5/00—Making pig-iron in the blast furnace
- C21B5/001—Injecting additional fuel or reducing agents
- C21B5/003—Injection of pulverulent coal
- C21B5/004—Injection of slurries
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
- C10L1/00—Liquid carbonaceous fuels
- C10L1/32—Liquid carbonaceous fuels consisting of coal-oil suspensions or aqueous emulsions or oil emulsions
- C10L1/322—Coal-oil suspensions
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Liquid Carbonaceous Fuels (AREA)
- Solid Fuels And Fuel-Associated Substances (AREA)
Abstract
TITLE
AN IN-LINE METHOD FOR THE BENEFICIATION OF COAL AND THE
FORMATION OF A COAL-IN-OIL COMBUSTIBLE FUEL THEREFROM
INVENTORS
C. EDWARD CAPES
WILLIAM L. THAYER
RICHARD D. COLEMAN
ABSTRACT OF DISCLOSURE
An in-line method for the beneficiation of coal and the formation of a coal-in-oil combustible fuel wherein the coal is wet pulverized, micro-agglomerated with light oil to dissociate a large amount of inorganic impurities and some water agglomerated with heavy oil to form rela-tively larger agglomerates and dissociate mainly water with some inorganic impurities, and then mixed with further heavy oil to form the coal in oil combustible fuel.
AN IN-LINE METHOD FOR THE BENEFICIATION OF COAL AND THE
FORMATION OF A COAL-IN-OIL COMBUSTIBLE FUEL THEREFROM
INVENTORS
C. EDWARD CAPES
WILLIAM L. THAYER
RICHARD D. COLEMAN
ABSTRACT OF DISCLOSURE
An in-line method for the beneficiation of coal and the formation of a coal-in-oil combustible fuel wherein the coal is wet pulverized, micro-agglomerated with light oil to dissociate a large amount of inorganic impurities and some water agglomerated with heavy oil to form rela-tively larger agglomerates and dissociate mainly water with some inorganic impurities, and then mixed with further heavy oil to form the coal in oil combustible fuel.
Description
~7~
This invention relates to an in-line method for the beneficiation of coal and the formation of a coal-in-oil combustible fuel therefrom.
I-t has already been proposed in United States Patent No. 3,665,066, dated May 23, 1972, "Beneficiation of Coals", Capes et al, to beneficiate a coal slurry effluent by mixing a bridging liquid (light hydrocarbon oil) with coal fines and agita~ing the formed mixture in an aqueous medium to cause agglomeration of the coal particles. The coal particle ayglomerates are then at least partially dewatered and fed to a balling device, together with balling nuclei of relatively coarse coal particles and binding oil (heavy hydrocarbon oil) to form a balled product in which each ball comprises at least one balling nucleus in association with coal particles from the agglomerates. The coal fines may contain significant proportions of hydrophilic (or oleophobic) impurity or ash-forminy particles a~sed of silica, alumina, pyrite, etc.
to which the functional groups of the light hydrocarbon oil bridging liquid are incapable of attaching themselves so that when the coal particle agglomerates are formed, these particles remain suspended in the water and are thus effectively separated from the coal particles.
While the process disclosed in the Capes et al patent has proved to be useful for the production of relatively coarse, balled coal products in the range 1/8 inch (3.2 mm) to 1 inch ~25.4 ~n) which are sufficiently stronq to be transported in the balled form without the balls disintegrating or releasing coal dust, there is a need for a process for the production of relatively ~ine, irnpurity liberated balled coal products having ~1~78~34 an average size no greater than of the order of 3 mm in order that the balls will readily disperse in ~il to form a co~bustible fuel comprising a coal-in-oil suspen-sion. Impurity liberated coal-in-oil suspensions would be a useful alternative fuel for existing oil fired electrical generating facilities resulting in a saving in the oil consumption. Other possible uses for these suspensions are marine fuels, fuels for industrial boilers and as injected fuels for blast furnaces.
In Canadian Patent No~ 1,020,880, dated November 15, 1977, "A method of displacing liquid suspendant of a particulate material, liquid suspendant mixture by micro-ag~lomeration" Capes et al, there is described an in-line, one stage agglomerating process for producing micro-agglomerates of coal fines which is particularly useful for minimiæing the moisture content o coal-in-oil suspensions for transportation along long distance pipelines. ~hile this process is useful for the purpose for which it was developed, there is still a need for this process to be developed further to produce a combustible fuel comprising an impurity liberated coal-in-oil suspension wherein more accurate control of and larger amounts of the residual moisture content remaining in the fuel from the original coal-in-water slurry can be achieved. One reason for this may be that the residual moisture content of the coal-in-oil suspension explodes in a combustion chamber and this possibl~r aids in dispersing the oil and coal and thus in combustion efficiency.
~17~84 Controlled moisture content could also be useful when the coal-in-oil suspension is subjected to vibratory energy such as, for example, in burners which use vibratory energy to increase the combustion efficieney in combustion chambers.
Accordiny to the present invention there is provided an in-line method for the benefielation of coal and the ~o~ma-tion of a coal-i.n-oil combustible fuel therefrom comprising:
a) comminuting coal in water to produce a coal-in-water slurry comprising impurity liberated coal particles at least as fine as 40 microns weight mean particle size, then b) m;xing the coal-in-water slurry with light oil agglomerating liquid additive having a specifie gravity of less than of the~.order of 1 g/cm3 to miero-agglomerate the impurity liberated eoal partieles and primarily dissoeiat~ inorganic impurities and some watex therefrom,the light oil agglomera-ting liquid additive being added at not more than of the order of 20 wt % of the total weight of the solids of the eoal-in-water slurry, then e) separating the micro-agglomerated, impurity - liberated eoal from the dissociated inorgan.ie impurities and water, then d) mixing - the separated~ micro-agglomerated, impurity liberated eoal with heavy fuel oi~ having a specific ~ravity greater than of the order ofi 0.~ g/cm3, as agglomerating liquid to produce relatively larger agglomerates eomprising an ~7~
average size no greater than of the order of 3 mm and primarily dissociate water with some inorc~anic impurities which were present in the micro-agylomera-ted, impurity liberated coal and leave a residual amount of at least of the order of S wt ~ water in the relatively larger agglomerates, then e) separating the relatively larger agglomerates from the dissociated water and inorganic im-purities, and then f) mixiny -~he separated~ relatively larger agglomerates with make-up heavy oil additive to form a coal-in-oil combustible fuel.
In the accompanying drawing which illustrates, by way of example, an embodiment oI` the present invention there is shown a flow diagram of an in-line method for t~-c be~eficiation of coal and the formation of a coal-in-oil combustible fuel therefrom.
In Figure 1 there is shown an in-line method for the beneficiation of coal and the formation of a coal-in-oil combustible fuel therefromp comprising:
a) comminuting coal-in-water, in a ~et mill 1, to produce a coal-in-water slurry 2 comprising im~
- purity li.berated coal particles at least as fine as 40 microns weight mean particle size, then b) mixing the coal-in-water slurry 2, in three stlrring devices 4 to 6 arranged in cascade, with ligh-t oil 8, having a specific ~ravity of less than of the order of 1 g/cm3, as acJgIomerating li~uid to micro-~.gglomerate the impurity liberated 788~
coal particles and primarily dissociate inorganic impurities and some water tnerefrom, the light oil agglomerati.ng liquid 8 being added at not more than o the order of 20 wt % of the total weight of the solids of the coal-in-water slurry
This invention relates to an in-line method for the beneficiation of coal and the formation of a coal-in-oil combustible fuel therefrom.
I-t has already been proposed in United States Patent No. 3,665,066, dated May 23, 1972, "Beneficiation of Coals", Capes et al, to beneficiate a coal slurry effluent by mixing a bridging liquid (light hydrocarbon oil) with coal fines and agita~ing the formed mixture in an aqueous medium to cause agglomeration of the coal particles. The coal particle ayglomerates are then at least partially dewatered and fed to a balling device, together with balling nuclei of relatively coarse coal particles and binding oil (heavy hydrocarbon oil) to form a balled product in which each ball comprises at least one balling nucleus in association with coal particles from the agglomerates. The coal fines may contain significant proportions of hydrophilic (or oleophobic) impurity or ash-forminy particles a~sed of silica, alumina, pyrite, etc.
to which the functional groups of the light hydrocarbon oil bridging liquid are incapable of attaching themselves so that when the coal particle agglomerates are formed, these particles remain suspended in the water and are thus effectively separated from the coal particles.
While the process disclosed in the Capes et al patent has proved to be useful for the production of relatively coarse, balled coal products in the range 1/8 inch (3.2 mm) to 1 inch ~25.4 ~n) which are sufficiently stronq to be transported in the balled form without the balls disintegrating or releasing coal dust, there is a need for a process for the production of relatively ~ine, irnpurity liberated balled coal products having ~1~78~34 an average size no greater than of the order of 3 mm in order that the balls will readily disperse in ~il to form a co~bustible fuel comprising a coal-in-oil suspen-sion. Impurity liberated coal-in-oil suspensions would be a useful alternative fuel for existing oil fired electrical generating facilities resulting in a saving in the oil consumption. Other possible uses for these suspensions are marine fuels, fuels for industrial boilers and as injected fuels for blast furnaces.
In Canadian Patent No~ 1,020,880, dated November 15, 1977, "A method of displacing liquid suspendant of a particulate material, liquid suspendant mixture by micro-ag~lomeration" Capes et al, there is described an in-line, one stage agglomerating process for producing micro-agglomerates of coal fines which is particularly useful for minimiæing the moisture content o coal-in-oil suspensions for transportation along long distance pipelines. ~hile this process is useful for the purpose for which it was developed, there is still a need for this process to be developed further to produce a combustible fuel comprising an impurity liberated coal-in-oil suspension wherein more accurate control of and larger amounts of the residual moisture content remaining in the fuel from the original coal-in-water slurry can be achieved. One reason for this may be that the residual moisture content of the coal-in-oil suspension explodes in a combustion chamber and this possibl~r aids in dispersing the oil and coal and thus in combustion efficiency.
~17~84 Controlled moisture content could also be useful when the coal-in-oil suspension is subjected to vibratory energy such as, for example, in burners which use vibratory energy to increase the combustion efficieney in combustion chambers.
Accordiny to the present invention there is provided an in-line method for the benefielation of coal and the ~o~ma-tion of a coal-i.n-oil combustible fuel therefrom comprising:
a) comminuting coal in water to produce a coal-in-water slurry comprising impurity liberated coal particles at least as fine as 40 microns weight mean particle size, then b) m;xing the coal-in-water slurry with light oil agglomerating liquid additive having a specifie gravity of less than of the~.order of 1 g/cm3 to miero-agglomerate the impurity liberated eoal partieles and primarily dissoeiat~ inorganic impurities and some watex therefrom,the light oil agglomera-ting liquid additive being added at not more than of the order of 20 wt % of the total weight of the solids of the eoal-in-water slurry, then e) separating the micro-agglomerated, impurity - liberated eoal from the dissociated inorgan.ie impurities and water, then d) mixing - the separated~ micro-agglomerated, impurity liberated eoal with heavy fuel oi~ having a specific ~ravity greater than of the order ofi 0.~ g/cm3, as agglomerating liquid to produce relatively larger agglomerates eomprising an ~7~
average size no greater than of the order of 3 mm and primarily dissociate water with some inorc~anic impurities which were present in the micro-agylomera-ted, impurity liberated coal and leave a residual amount of at least of the order of S wt ~ water in the relatively larger agglomerates, then e) separating the relatively larger agglomerates from the dissociated water and inorganic im-purities, and then f) mixiny -~he separated~ relatively larger agglomerates with make-up heavy oil additive to form a coal-in-oil combustible fuel.
In the accompanying drawing which illustrates, by way of example, an embodiment oI` the present invention there is shown a flow diagram of an in-line method for t~-c be~eficiation of coal and the formation of a coal-in-oil combustible fuel therefrom.
In Figure 1 there is shown an in-line method for the beneficiation of coal and the formation of a coal-in-oil combustible fuel therefromp comprising:
a) comminuting coal-in-water, in a ~et mill 1, to produce a coal-in-water slurry 2 comprising im~
- purity li.berated coal particles at least as fine as 40 microns weight mean particle size, then b) mixing the coal-in-water slurry 2, in three stlrring devices 4 to 6 arranged in cascade, with ligh-t oil 8, having a specific ~ravity of less than of the order of 1 g/cm3, as acJgIomerating li~uid to micro-~.gglomerate the impurity liberated 788~
coal particles and primarily dissociate inorganic impurities and some water tnerefrom, the light oil agglomerati.ng liquid 8 being added at not more than o the order of 20 wt % of the total weight of the solids of the coal-in-water slurry
2, then c~ separating, on a dewatexing screen 10 the micro-agglomerated, impurity liberated coal from the dissociated inorganic impurities and water, then d) mixlng the separated, micro-agglomerated~
impurity liberated coal 12, in a stirrer ].4, with heavy fuel oil 16, having a specific gravity greater than of the order of 0.9 g/cm3~ as agglo-merating liquid to produce relatively larger agglomerates comprising an average size no greater than of the order of 3mm and primarily dissociate water with some inorganic impurities which were present in the 2Q micro-agglomerated, impurity li~erated coal and leave a residual amount of at least of the order of 5 wt % in the relatively larger agglome-rates, then e) separating the relatively larger agglomerates, on a vibrating screen 18, from the dissociated water and inorganic impurities, and then P) mixing the separated, relati~ely larger agglomerates i`0, in a mixe~ 22, with make up heavy oil additive 24 to form a coal-in-oil combustible fuel 26.
~ 5 -~7~
The dry pulverizer 28 is used for the initial stage of yrinding since this will generally pulverize coal faster and in a smaller equipment volume than with wet methods, although wet yrinding may be used throughout, if desired.
Coal to be pulverized is fed from a storage hopper 30 to the dry pulverizer 28 which is s~ept wi-th air from a supply 32. The swept air, with entrained pulverized coal, is fed from the pulverizer 28 to a wet scrubber 34.
~ater containing the pulverized coal is fed from the wet scrubber 34 to the wet mill 1 while air, which has been scrubbed free from the pulveriæed coal in the wet scrubber
impurity liberated coal 12, in a stirrer ].4, with heavy fuel oil 16, having a specific gravity greater than of the order of 0.9 g/cm3~ as agglo-merating liquid to produce relatively larger agglomerates comprising an average size no greater than of the order of 3mm and primarily dissociate water with some inorganic impurities which were present in the 2Q micro-agglomerated, impurity li~erated coal and leave a residual amount of at least of the order of 5 wt % in the relatively larger agglome-rates, then e) separating the relatively larger agglomerates, on a vibrating screen 18, from the dissociated water and inorganic impurities, and then P) mixing the separated, relati~ely larger agglomerates i`0, in a mixe~ 22, with make up heavy oil additive 24 to form a coal-in-oil combustible fuel 26.
~ 5 -~7~
The dry pulverizer 28 is used for the initial stage of yrinding since this will generally pulverize coal faster and in a smaller equipment volume than with wet methods, although wet yrinding may be used throughout, if desired.
Coal to be pulverized is fed from a storage hopper 30 to the dry pulverizer 28 which is s~ept wi-th air from a supply 32. The swept air, with entrained pulverized coal, is fed from the pulverizer 28 to a wet scrubber 34.
~ater containing the pulverized coal is fed from the wet scrubber 34 to the wet mill 1 while air, which has been scrubbed free from the pulveriæed coal in the wet scrubber
3~, is exhausted therefrom at 36.
As previously stated the coal-in-water slurry 2 from the wet mill 1 is stirred in three mixing devices
As previously stated the coal-in-water slurry 2 from the wet mill 1 is stirred in three mixing devices
4 to 6 arranged in cascade. One mixing device could be used provided that the residence time for the coal of the coal-in-water slurry 2 therein to he micro-agglomerated is tolerable. With the embodiment shown in Figure 1, a residence time of four minutes was required and so the three mixing devices 4 to 6 were provided.
The first mixing device 4 is a high shear mixing device and may be a conventional turbine mixer.
The first mixing device 4 is used to disperse the light oil agglomerating liquid 8 in the coal-in-water slurry 2 and give an initial mixing.
The second and third mixing devices, 5 and 6 respectively, are relatively lower blade speed, intermediate intensity mixing devices -to the mixing device 4 and are for producing the micro-agglomerates. It should be noted that in dif~erent embodiments of the present invention, ~7~8~
only one lower, intermediate inte-nsity mixing device is necessary and in other em~odiments different mixing devices may be used, such as, for example, one or more emulsifying units with or without one or more lower, intermediate intensity mixing devices.
The ligh~ oil agglomerating liquid additive 8 is fed to the first mixing device 4 from a storage tank 38.
As previously stated the micro-agglomerated, impurity liberated coal is separated from the dissociated components comprising primarily inorganic impurities and some water on the screen 10~ which in this embodiment is a stationary incli.ned screen down which the separated, micro-agglomerated) impurity libera~ed coal rolls and emerges as micxo-agglomerates 12 while the dissociated inorganic impurit.ies and water, designated 40t drain through the screen and are conveyed to a settling pond 42. A vibrating screen separator or wet cyclone separator could be used at this stage if the micro-agglomerates possess suffici.ent streng~h not to break up in such apparatus.
The embodiment shown in Figure 1 is arranged to recycle most of the water from delivery 40 to the settling tank 42, together with make-up water 44 which is fed thereto. The water 46 from the settling tank provides feed to the wet scrubber 34, wet mill 1 and the first mixing device 4.
The micro-agglomerates 12 then pass to the mixing device 14 which is also a re~atively lower blade speed, intermediate intensity mixing device to the mixing device 4.
1~17~
The relatively larger agglomerates are separated from the dissoci~lted water and inorganic impurities on the vibrating screen 18 because the relatively larger agglomer-ates have suEficient strength no-t to break up on the vibrating screen 18 r which is an e~ficient separator for the pur~pose.
A wet cyclone separa-tor, other types of screens, etc., could also be used at this stage if desired.
The dissociated water and inorganic impurities, designated 48, drain through the vibrating screen 18 and are conveyed to a separation tank 50 from which a portion 52 of the ~ater is returned to the stirrer 14 while the remaining water and inorganic impurities 54 are conveyed to the settling pond 42.
The reason wh~ the water portion 52 is returned to the mixing device 14 is to ensure that sufficient water is delivered, ~ith the relatively larger agglomerates, to the vibrating screen 18 to ensure that the inorganic impuri-ties are thoroug~ly washed from the relatively larger agglo-merates. This su~stantially reduces the possi~ility of inorganic impurities ~eing carried over the ~i~rating screen 1~ with the relatively larger agglomerates. In addition, the water in mixing device 14 would usually be heated to about 60C to reduce the viscosity of the heavy fuel oil 16. Recirculation of water portion 52 avoids loss of thermal energy in discarded hot water.
The mixer-22l to which the relatively larger agglomerates 20 are conveyed in this embodiment is a stationary, cylindrical vessel llaving a mixing device rotating about a horizontal axis. Other types of mi~ers may also be used such as, for example, a paddle type mixer.
The coal-in-oil combustible fuel 26 is stored in an agitated holdin~ tank 56 from which it is with-~7~38~
drawn by a pump 58 ~t the desired rate ~o cons~nption asa co~bustible f-lel in, for example, an electrical power generating ins-tallation (not shown). The method can be matched to the desired rate of c~nsumption of the com-bustible fuel so that the holding tank 56 is merely pro-vided for storage to accommodate any fluctuations in the production of the coal-in-oil combustible fuel or the consumption thereof.
Details of an example using the method shown in Figure 1 to bene~iciate coal mined from Minto, New Brunswick, Canada and to form a coal-in-oil combust~ble fuel therefrom will now be givèn.
A typical analysis of the Minto coal is given below which shows that this is a coal having a high ash and sulphur content.
Proximate Analysis (as fired) Norm Worst Moisture 6.0% 12.0%
Volatile Matter 30.0% 24.2%
Fixed Carbon 46.0% 33.8%
Ash 18~0% 3n . o%
Sulphur 8.0% 10.0%
Btu/lb. (as fired) 11,300 8,400 (kj/kg1 (as fired)(26,284~ (19,540) Grindability (Hardgrove)70 60 Ash Fusibility Initial deformation, ~F ( C) 1,780 ( 970) 1,730 ( 940) Softeningf F (C) 1,900 (1,040) 1,850 (1,010) Fluid, F (C) 1,970 (1,080) 1,920 (1,050) The weigh-t ratio of air to coal fed to the dr~
pulveriæer 28 was in the range 1.5:1- to 2:1. of the order of 40 wt % coal and 60 wt % water were present in the wet mill 1.
The first mixing device 4 was fed of the order of 20 wt % coal, 3 wt ~ No. 2 fuel oil and 77 wt % water The plant was a pilot plant desicJned to be capable of treating 100 Imperial gallons/minO (455 l/min.) of slurry 2, which is equivalent to about 6 tons/hour(5.44 t~nnes/hour) of coal solids (including impurities) based on the 20 wt %
slurry fed to the first mixing device 4.
The blades of the high shear mixing device 4, which were driven by a 5 HP motor at 3,220 rpm, comprised two groups of four ~igh shear impeller'blades, two of which are shown for each ~roup and designated 60 to 63,'which ~a~er~n radi~ out~ardly to~ard~-trunca ed extr~itie.s. ' ~ The high shear impeller blades 6~ and 62 ~r~re mounted in an 18 inch ~0.46-m~ internal diameter tank 64 hav~ng a 35 inch CQ'.'8q' ml height with an annular baffle 66 between the impeller blades 60 and 62 and four vertical baffles, two of which are shown and designated 68 and 70, equally spaced therearound to enhance their shearing effect on the coal-in-~ater slurry 2.
The four blades'of each of the relatively lower blade speed, intermediate intensity mixing devices 5, 6 and 14, which were driven by a 5 HP motor at 280 rpm comprised pitched, turbine impell'ér blades two of which are shown and designated 72 and 74. The blades 72 and 74 were rnounted in a 40 in. (1.02 m) internal diameter vessel having a 4G in~ (1.02 r,l) overflow heigh-t with four vertical baffles, two of which are shown and designated 7~
76 and 78, equally spaced around the blades 72 and 74 to enhance their shearing effect.
The dissociated inorganic impurities and ~tater, designated 40, mainly comprised of the order of 96 wt %
water and 3 wt % ash and sulphur as the main inorganic impurities together with oE the order of 1 wt % unagglomera-ted combustible matter.
T~ relatively larger agglomerates produced by mixer 14 comprised of the order of 70 wt % coal, 20 wt ~
oil and 10 wt % waker to which was added sufficient No. 6 fuel oil in the mixer 22 for the coal~in-oil combusti~le fuel ~6 to comprise a coal~oil weight rat.io of 40/60b Tests have shown tha~ using apparatus o the type shown in Figure 1, then:
~) the preferred ~lade tip speed of the hig~ shear impeller ~lades 60 to 63 is in the range of the order of 10 m/sec. to of the order of 30 m/sec.
bet~er still of the order of 20 m/s~c. to of the order of 25 m/sec.
ii) the preferred blade tip speed of the pitched, turbine impeller blades 72 and 74 is up to of the order of 15 m/sec.
Preferred light oils as-agglomerating lic~uid are No~ 2 fuel oil and diesel o:il. Other light oils as agglomera-ting liquid are, for example~ light petroleum fractions, kero-sene, coke oven light oil and light crude and residual and waste oils.
Preferred heavy fuel oils as agglomerating liquid are No. 6 fuel oil and heavy residual oils. Other heavy fuel oils as agglomerating liquid are, for example, crude oi]s and coXe oven tar.
7~
The quantity of liyh-t oil agglomerating liquid additive used will depend upon the type of coal being pro-cessed and how finely the coal must ~e ground to produce impurity liberated coal particles. Wnile a greater quantity of light oil agglomerating liquid additive could be used than of the order of 20 wt % of the -total weight of solids of the coal-in-water slurry the desira~le thing according to the present invention is that onl~ of the order of up to 20 wt % need ~e used so that the final coal-in-oil combustible fuel will containS fox example, the maximum amount of heavy oil ror which an oil fired installation was originally des.igned, when the coal-in-oil com~ustible fuel i~ for use in this manner.
_ 12 ~
The first mixing device 4 is a high shear mixing device and may be a conventional turbine mixer.
The first mixing device 4 is used to disperse the light oil agglomerating liquid 8 in the coal-in-water slurry 2 and give an initial mixing.
The second and third mixing devices, 5 and 6 respectively, are relatively lower blade speed, intermediate intensity mixing devices -to the mixing device 4 and are for producing the micro-agglomerates. It should be noted that in dif~erent embodiments of the present invention, ~7~8~
only one lower, intermediate inte-nsity mixing device is necessary and in other em~odiments different mixing devices may be used, such as, for example, one or more emulsifying units with or without one or more lower, intermediate intensity mixing devices.
The ligh~ oil agglomerating liquid additive 8 is fed to the first mixing device 4 from a storage tank 38.
As previously stated the micro-agglomerated, impurity liberated coal is separated from the dissociated components comprising primarily inorganic impurities and some water on the screen 10~ which in this embodiment is a stationary incli.ned screen down which the separated, micro-agglomerated) impurity libera~ed coal rolls and emerges as micxo-agglomerates 12 while the dissociated inorganic impurit.ies and water, designated 40t drain through the screen and are conveyed to a settling pond 42. A vibrating screen separator or wet cyclone separator could be used at this stage if the micro-agglomerates possess suffici.ent streng~h not to break up in such apparatus.
The embodiment shown in Figure 1 is arranged to recycle most of the water from delivery 40 to the settling tank 42, together with make-up water 44 which is fed thereto. The water 46 from the settling tank provides feed to the wet scrubber 34, wet mill 1 and the first mixing device 4.
The micro-agglomerates 12 then pass to the mixing device 14 which is also a re~atively lower blade speed, intermediate intensity mixing device to the mixing device 4.
1~17~
The relatively larger agglomerates are separated from the dissoci~lted water and inorganic impurities on the vibrating screen 18 because the relatively larger agglomer-ates have suEficient strength no-t to break up on the vibrating screen 18 r which is an e~ficient separator for the pur~pose.
A wet cyclone separa-tor, other types of screens, etc., could also be used at this stage if desired.
The dissociated water and inorganic impurities, designated 48, drain through the vibrating screen 18 and are conveyed to a separation tank 50 from which a portion 52 of the ~ater is returned to the stirrer 14 while the remaining water and inorganic impurities 54 are conveyed to the settling pond 42.
The reason wh~ the water portion 52 is returned to the mixing device 14 is to ensure that sufficient water is delivered, ~ith the relatively larger agglomerates, to the vibrating screen 18 to ensure that the inorganic impuri-ties are thoroug~ly washed from the relatively larger agglo-merates. This su~stantially reduces the possi~ility of inorganic impurities ~eing carried over the ~i~rating screen 1~ with the relatively larger agglomerates. In addition, the water in mixing device 14 would usually be heated to about 60C to reduce the viscosity of the heavy fuel oil 16. Recirculation of water portion 52 avoids loss of thermal energy in discarded hot water.
The mixer-22l to which the relatively larger agglomerates 20 are conveyed in this embodiment is a stationary, cylindrical vessel llaving a mixing device rotating about a horizontal axis. Other types of mi~ers may also be used such as, for example, a paddle type mixer.
The coal-in-oil combustible fuel 26 is stored in an agitated holdin~ tank 56 from which it is with-~7~38~
drawn by a pump 58 ~t the desired rate ~o cons~nption asa co~bustible f-lel in, for example, an electrical power generating ins-tallation (not shown). The method can be matched to the desired rate of c~nsumption of the com-bustible fuel so that the holding tank 56 is merely pro-vided for storage to accommodate any fluctuations in the production of the coal-in-oil combustible fuel or the consumption thereof.
Details of an example using the method shown in Figure 1 to bene~iciate coal mined from Minto, New Brunswick, Canada and to form a coal-in-oil combust~ble fuel therefrom will now be givèn.
A typical analysis of the Minto coal is given below which shows that this is a coal having a high ash and sulphur content.
Proximate Analysis (as fired) Norm Worst Moisture 6.0% 12.0%
Volatile Matter 30.0% 24.2%
Fixed Carbon 46.0% 33.8%
Ash 18~0% 3n . o%
Sulphur 8.0% 10.0%
Btu/lb. (as fired) 11,300 8,400 (kj/kg1 (as fired)(26,284~ (19,540) Grindability (Hardgrove)70 60 Ash Fusibility Initial deformation, ~F ( C) 1,780 ( 970) 1,730 ( 940) Softeningf F (C) 1,900 (1,040) 1,850 (1,010) Fluid, F (C) 1,970 (1,080) 1,920 (1,050) The weigh-t ratio of air to coal fed to the dr~
pulveriæer 28 was in the range 1.5:1- to 2:1. of the order of 40 wt % coal and 60 wt % water were present in the wet mill 1.
The first mixing device 4 was fed of the order of 20 wt % coal, 3 wt ~ No. 2 fuel oil and 77 wt % water The plant was a pilot plant desicJned to be capable of treating 100 Imperial gallons/minO (455 l/min.) of slurry 2, which is equivalent to about 6 tons/hour(5.44 t~nnes/hour) of coal solids (including impurities) based on the 20 wt %
slurry fed to the first mixing device 4.
The blades of the high shear mixing device 4, which were driven by a 5 HP motor at 3,220 rpm, comprised two groups of four ~igh shear impeller'blades, two of which are shown for each ~roup and designated 60 to 63,'which ~a~er~n radi~ out~ardly to~ard~-trunca ed extr~itie.s. ' ~ The high shear impeller blades 6~ and 62 ~r~re mounted in an 18 inch ~0.46-m~ internal diameter tank 64 hav~ng a 35 inch CQ'.'8q' ml height with an annular baffle 66 between the impeller blades 60 and 62 and four vertical baffles, two of which are shown and designated 68 and 70, equally spaced therearound to enhance their shearing effect on the coal-in-~ater slurry 2.
The four blades'of each of the relatively lower blade speed, intermediate intensity mixing devices 5, 6 and 14, which were driven by a 5 HP motor at 280 rpm comprised pitched, turbine impell'ér blades two of which are shown and designated 72 and 74. The blades 72 and 74 were rnounted in a 40 in. (1.02 m) internal diameter vessel having a 4G in~ (1.02 r,l) overflow heigh-t with four vertical baffles, two of which are shown and designated 7~
76 and 78, equally spaced around the blades 72 and 74 to enhance their shearing effect.
The dissociated inorganic impurities and ~tater, designated 40, mainly comprised of the order of 96 wt %
water and 3 wt % ash and sulphur as the main inorganic impurities together with oE the order of 1 wt % unagglomera-ted combustible matter.
T~ relatively larger agglomerates produced by mixer 14 comprised of the order of 70 wt % coal, 20 wt ~
oil and 10 wt % waker to which was added sufficient No. 6 fuel oil in the mixer 22 for the coal~in-oil combusti~le fuel ~6 to comprise a coal~oil weight rat.io of 40/60b Tests have shown tha~ using apparatus o the type shown in Figure 1, then:
~) the preferred ~lade tip speed of the hig~ shear impeller ~lades 60 to 63 is in the range of the order of 10 m/sec. to of the order of 30 m/sec.
bet~er still of the order of 20 m/s~c. to of the order of 25 m/sec.
ii) the preferred blade tip speed of the pitched, turbine impeller blades 72 and 74 is up to of the order of 15 m/sec.
Preferred light oils as-agglomerating lic~uid are No~ 2 fuel oil and diesel o:il. Other light oils as agglomera-ting liquid are, for example~ light petroleum fractions, kero-sene, coke oven light oil and light crude and residual and waste oils.
Preferred heavy fuel oils as agglomerating liquid are No. 6 fuel oil and heavy residual oils. Other heavy fuel oils as agglomerating liquid are, for example, crude oi]s and coXe oven tar.
7~
The quantity of liyh-t oil agglomerating liquid additive used will depend upon the type of coal being pro-cessed and how finely the coal must ~e ground to produce impurity liberated coal particles. Wnile a greater quantity of light oil agglomerating liquid additive could be used than of the order of 20 wt % of the -total weight of solids of the coal-in-water slurry the desira~le thing according to the present invention is that onl~ of the order of up to 20 wt % need ~e used so that the final coal-in-oil combustible fuel will containS fox example, the maximum amount of heavy oil ror which an oil fired installation was originally des.igned, when the coal-in-oil com~ustible fuel i~ for use in this manner.
_ 12 ~
Claims (5)
1. An in-line method for the beneficiation of coal and the formation of a coal-in-oil combustible fuel therefrom, comprising:
a) comminuting coal in water to produce a coal-in-water slurry comprising impurity lib-erated coal particles at least as fine as 40 microns weight mean particle size, then b) mixing the coal-in-water slurry with light oil as agglomerating liquid having a specific gravity of less than of the order of 1 g/cm to micro-agglomerate the impurity liberated coal particles and primarily dissociate inorganic impurities and some water therefrom, the light oil agglomerating liquid being added at not more than of the order, of 20 wt % of the total weight of the solids of the coal-in-water slurry, then c) separating the micro-agglomerated, impurity liberated coal from the dissociated inorganic impurities and water, then d) mixing the separated, micro-agglomerated, impurity liberated coal with heavy fuel oil, having a specific gravity greater than of the order of 0.9 g/cm , as agglomerating liquid to produce relatively larger agglomerates compris-ing an average size no greater than of the order of 3 mm and primarily dissociate water with some inorganic impurities which were present in the micro-agglomerated, impurity liberated coal and leave a residual amount of at least of the order of 5 wt % water in the relatively larger agglomerates, then e) separating the relatively larger agglomerates from the dissociated water and inorganic impurities, and then f) mixing the separated relatively larger agglo-merates with make-up heavy oil additive to form a coal-in-oil combustible fuel.
a) comminuting coal in water to produce a coal-in-water slurry comprising impurity lib-erated coal particles at least as fine as 40 microns weight mean particle size, then b) mixing the coal-in-water slurry with light oil as agglomerating liquid having a specific gravity of less than of the order of 1 g/cm to micro-agglomerate the impurity liberated coal particles and primarily dissociate inorganic impurities and some water therefrom, the light oil agglomerating liquid being added at not more than of the order, of 20 wt % of the total weight of the solids of the coal-in-water slurry, then c) separating the micro-agglomerated, impurity liberated coal from the dissociated inorganic impurities and water, then d) mixing the separated, micro-agglomerated, impurity liberated coal with heavy fuel oil, having a specific gravity greater than of the order of 0.9 g/cm , as agglomerating liquid to produce relatively larger agglomerates compris-ing an average size no greater than of the order of 3 mm and primarily dissociate water with some inorganic impurities which were present in the micro-agglomerated, impurity liberated coal and leave a residual amount of at least of the order of 5 wt % water in the relatively larger agglomerates, then e) separating the relatively larger agglomerates from the dissociated water and inorganic impurities, and then f) mixing the separated relatively larger agglo-merates with make-up heavy oil additive to form a coal-in-oil combustible fuel.
2. A method according to claim 1, wherein the coal is initially pulverized in a dry pulverizer, air is scrubbed free from the dry, pulverized coal in a wet scrubber and then the scrubbed, pulverized coal is com-minuted in water to produce the coal-in-water slurry.
3. A method according to claim 1, wherein the coal-in-water slurry is stirred with light oil agglomerating liquid initially in a high shear stirring device, to give an initial mixing, and then in at least one relatively lower blade speed, intermediate intensity mixing device.
4. A method according to claim 1, wherein the light oil as agglomerating liquid is selected from the group consisting of No. 2 fuel oil and diesel oil.
5. A method according to claim 1, wherein the heavy oil as agglomerating liquid is selected from the group consisting of No. 6 fuel oil and heavy residual oils.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000340749A CA1117884A (en) | 1979-11-22 | 1979-11-22 | In-line method for the beneficiation of coal and the formation of a coal-in-oil combustible fuel therefrom |
| DE8080304161T DE3068727D1 (en) | 1979-11-22 | 1980-11-20 | An in-line method for the upgrading of coal |
| EP19800304161 EP0029712B1 (en) | 1979-11-22 | 1980-11-20 | An in-line method for the upgrading of coal |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000340749A CA1117884A (en) | 1979-11-22 | 1979-11-22 | In-line method for the beneficiation of coal and the formation of a coal-in-oil combustible fuel therefrom |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1117884A true CA1117884A (en) | 1982-02-09 |
Family
ID=4115706
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000340749A Expired CA1117884A (en) | 1979-11-22 | 1979-11-22 | In-line method for the beneficiation of coal and the formation of a coal-in-oil combustible fuel therefrom |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP0029712B1 (en) |
| CA (1) | CA1117884A (en) |
| DE (1) | DE3068727D1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0170379A2 (en) * | 1984-06-19 | 1986-02-05 | The University Of Toronto Innovations Foundation | Method of separating solids by simultaneous comminution and agglomeration |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2526680B2 (en) * | 1978-12-04 | 1990-03-02 | American Minechem Corp | METHOD OF CONVERTING COAL MATERIALS INTO AN IMPROVED FEEDSTOCK |
| CA1216551A (en) * | 1984-05-23 | 1987-01-13 | Her Majesty The Queen In Right Of The Province Of Alberta As Represented By The Minister Of Energy And Natural Resources | Process for the selective agglomeration of sub- bituminous coal fines |
| US5096461A (en) * | 1989-03-31 | 1992-03-17 | Union Oil Company Of California | Separable coal-oil slurries having controlled sedimentation properties suitable for transport by pipeline |
| AU5349090A (en) * | 1989-03-31 | 1990-11-05 | Union Oil Company Of California | Separable coal-in-oil mixtures having controlled sedimentation properties and method for making same |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3665066A (en) * | 1969-11-28 | 1972-05-23 | Canadian Patents Dev | Beneficiation of coals |
| DE2640205A1 (en) * | 1975-09-09 | 1977-03-17 | Shell Int Research | METHOD FOR MANUFACTURING A SUSPENSION OF CARBON PARTICLES IN A HYDROCARBON FUEL |
-
1979
- 1979-11-22 CA CA000340749A patent/CA1117884A/en not_active Expired
-
1980
- 1980-11-20 EP EP19800304161 patent/EP0029712B1/en not_active Expired
- 1980-11-20 DE DE8080304161T patent/DE3068727D1/en not_active Expired
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0170379A2 (en) * | 1984-06-19 | 1986-02-05 | The University Of Toronto Innovations Foundation | Method of separating solids by simultaneous comminution and agglomeration |
| US4730787A (en) * | 1984-06-19 | 1988-03-15 | The University Of Toronto Innovations Foundation | Method of separating solids by simultaneous comminution and agglomeration |
| EP0170379A3 (en) * | 1984-06-19 | 1988-04-20 | University Of Toronto Innovations Foundation | Method of separating solids by simultaneous comminution and agglomeration |
| AU581895B2 (en) * | 1984-06-19 | 1989-03-09 | University Of Toronto Innovations Foundation, The | Method of separating solids by simultaneous comminution and agglomeration |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0029712B1 (en) | 1984-07-25 |
| DE3068727D1 (en) | 1984-08-30 |
| EP0029712A3 (en) | 1981-11-11 |
| EP0029712A2 (en) | 1981-06-03 |
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