EP0029712A2 - An in-line method for the upgrading of coal - Google Patents
An in-line method for the upgrading of coal Download PDFInfo
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- EP0029712A2 EP0029712A2 EP80304161A EP80304161A EP0029712A2 EP 0029712 A2 EP0029712 A2 EP 0029712A2 EP 80304161 A EP80304161 A EP 80304161A EP 80304161 A EP80304161 A EP 80304161A EP 0029712 A2 EP0029712 A2 EP 0029712A2
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- Prior art keywords
- coal
- oil
- water
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- 239000003245 coal Substances 0.000 title claims abstract description 63
- 238000000034 method Methods 0.000 title claims abstract description 22
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 59
- 239000003921 oil Substances 0.000 claims abstract description 44
- 239000012535 impurity Substances 0.000 claims abstract description 26
- 239000000446 fuel Substances 0.000 claims abstract description 24
- 239000002002 slurry Substances 0.000 claims abstract description 20
- 239000000295 fuel oil Substances 0.000 claims abstract description 8
- 230000015572 biosynthetic process Effects 0.000 claims abstract description 6
- 238000002156 mixing Methods 0.000 claims description 37
- 239000007788 liquid Substances 0.000 claims description 24
- 239000002245 particle Substances 0.000 claims description 20
- 239000000654 additive Substances 0.000 claims description 7
- 230000000996 additive effect Effects 0.000 claims description 7
- 230000005484 gravity Effects 0.000 claims description 6
- 239000010763 heavy fuel oil Substances 0.000 claims description 6
- 239000007787 solid Substances 0.000 claims description 5
- 239000010743 number 2 fuel oil Substances 0.000 claims description 3
- 239000010747 number 6 fuel oil Substances 0.000 claims description 3
- 239000002283 diesel fuel Substances 0.000 claims description 2
- 238000003756 stirring Methods 0.000 claims description 2
- 239000012053 oil suspension Substances 0.000 description 6
- 238000002485 combustion reaction Methods 0.000 description 4
- 239000004215 Carbon black (E152) Substances 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 229930195733 hydrocarbon Natural products 0.000 description 3
- 150000002430 hydrocarbons Chemical class 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 238000003860 storage Methods 0.000 description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 2
- 239000005864 Sulphur Substances 0.000 description 2
- 238000005054 agglomeration Methods 0.000 description 2
- 239000000571 coke Substances 0.000 description 2
- 238000009434 installation Methods 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 238000010008 shearing Methods 0.000 description 2
- 230000002776 aggregation Effects 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 239000012736 aqueous medium Substances 0.000 description 1
- 239000002817 coal dust Substances 0.000 description 1
- 239000003250 coal slurry Substances 0.000 description 1
- 239000010779 crude oil Substances 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000010494 dissociation reaction Methods 0.000 description 1
- 230000005593 dissociations Effects 0.000 description 1
- 230000001804 emulsifying effect Effects 0.000 description 1
- 125000000524 functional group Chemical group 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 239000003350 kerosene Substances 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000011236 particulate material Substances 0.000 description 1
- 239000003208 petroleum Substances 0.000 description 1
- 238000010298 pulverizing process Methods 0.000 description 1
- NIFIFKQPDTWWGU-UHFFFAOYSA-N pyrite Chemical compound [Fe+2].[S-][S-] NIFIFKQPDTWWGU-UHFFFAOYSA-N 0.000 description 1
- 229910052683 pyrite Inorganic materials 0.000 description 1
- 239000011028 pyrite Substances 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- 238000001238 wet grinding Methods 0.000 description 1
Images
Classifications
-
- 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
Definitions
- This invention relates to an in-line,method for the beneficiation of coal and the formation of a coal-in-oil combustible fuel therefrcm.
- the coal fines may contain significant proportions of hydrophilic (or oleophobic) impurity or ash-forming particles composed 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.
- hydrophilic (or oleophobic) impurity or ash-forming particles composed of silica, alumina, pyrite, etc.
- 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.
- 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 efficiency in combustion chambers.
- an in-line method for the beneficiation of coal and the formation of a coal-in-oil combustible fuel therefrom comprising:
- FIG. 1 there is shown an in-line method for the beneficiation of coal and the formation of a coal-in-oil combustible fuel therefrom, comprising:
- a dry pulverizer 28 is used for the initial stage of grinding since this will generally pulverize coal faster and in a smaller equipment volume than with wet methods, although wet grinding may be used throughout, if desired.
- the coal is ground down to a required particle size sufficient to effect separation or dissociation of coal particles and impurities.
- Coal to be pulverized is fed from a storage hopper 30 to the dry pulverizer 28 which is swept with air from a supply 32.
- the swept air, with entrained pulverized coal is fed from the pulverizer 28 to a wet scrubber 34.
- Water containing the pulverized coal is fed from the wet scrubber 34 to ti.e wet mill 1 while air, which has been scrubbed free from the pulverized coal in the wet scrubber 34, is exhausted therefrom at 36.
- 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 be 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 as compared with the mixing device 4 and are for producing the micro-agglomerates. It should be noted that in different embodiments of the present invention, only one lower, intermediate-intensity mixing device is necessary and in other embodiments 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 light oil agglomerating liquid additive 8 is fed to the first mixing device 4 from a storage tank 38.
- micro-agglomerated, impurity-liberated coal is separated from the dissociated components comprising primarily a large amount of inorganic impurities and some water on the screen 10, which in this embodiment is a stationary, inclined screen down which the separated, micro-agglomerated, impurity-liberated coal rolls and emerges as micro-agglomerates 12 while the dissociated inorganic impurities and water, designated 40, 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 sufficient strength 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 relatively lower blade speed, intermediate intensity mixing device as compared with the mixing device 4.
- the relatively larger agglomerates are separated from the dissociated water and inorganic impurities on the vibrating screen 18 because the relatively larger agglomerates have sufficient strength not to break up on the vibrating screen 18, which is an efficient separator for the purpose.
- a wet cyclone separator, other types of screens, etc., could also be used at this stage if desired.
- the reason why the water portion 52 is returned to the mixing device 14 is to ensure that sufficient water is delivered, with the relatively larger agglomerates, to the vibrating screen 18 to ensure that the inorganic impurities are thoroughly washed from the relatively larger agglomerates. This substantially reduces the possibility of inorganic impurities being carried over the vibrating screen 18 with the relatively larger agglomerates.
- the water in mixing device 14 would usually be heated to about 60°C 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 22, to which the relatively larger agglomerates 20 are conveyed in this embodiment is a stationary, cylindrical vessel having a mixing device rotating about a horizontal axis.
- Other types of mixers may also be used such aa, for example, a paddle type mixer.
- the coal-in-oil combustible fuel 26 is stored in an agitated condition in a holding tank 56 from which it is withdrawn by a pump 58 at the desired rate for consumption as a combustible fuel in, for example, an electrical power generating installation (not shown).
- the method can be matched to the desired rate of consumption of the combustible fuel so that the holding tank 56 is merely provided for storage to accommodate any fluctuations in the production of the coal-in-oil combustible fuel or the consumption thereof.
- Minto coal A typical analysis of the Minto coal is given below which shows that this is a coal having a high ash and sulphur content.
- the weight ratio of air to coal fed to the dry pulveriser 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 designed to be capable of treating 100 Imperial gallons/min. (455 1/min.) of slurry 2, which is equivalent to about 6 tons/hour (5.44 tonnes/ 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 high shear impeller blades, two of which are shown for each group and designated 60 to 63, which tapered radially outwardly towards truncated extremities.
- the high shear impeller blades 60 and 62 were mounted in an 18 inch (0.46 m) internal diameter tank 64 having a 35 inch (0.89 m) height with an annular baffle 66 between the impeller blades 60 and 62 and four vertical baffles, two of which are shown and desiccated 68 and 70, equally spaced therearound to enhance their shearing effect on the coal-in-water 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 impeller blades two of which are shown and designated 72 and 74.
- the blades 72 and 74 were mounted in a 40 in. (1.02 m) internal diameter vessel having a 40 in. (1.02 m) overflow height with four vertical baffles, two of which are shown and designated 76 and 78, equally spaced around the blades 72 and 74 to enhance their shearing effect.
- the dissociated inorganic impurities and water, designated 40 mainly comprised of the order of 96 wt % water and 3 wt % ash and sulphur as the main inorganic impurities together with of the order of 1 wt % unagglomer- ated combustible matter.
- the relatively larger agglomerates produced by mixer 14 comprised of the order of 70 wt % coal, 20 wt % oil and 10 wt % water to which was added sufficient No. 6 fuel oil in the mixer 22 for the coal-in-oil combustible fuel 26 to comprise a coal/oil weight ratio of 40/60.
- Preferred light oils as agglomerating liquid are No. 2 fuel oil and diesel oil.
- Other light oils as agglomerating liquid are, for example, light petroleum fractions, kerosene, 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 oils and coke oven tar.
- the quantity of light oil agglomerating liquid additive usod will depend upon the type of coal being processed and how finely the coal must be ground to produce impurity-liberated coal particles. While 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 desirable thing according to the present invention is that only of the order of up to 20 wt % need be used so that the final coal-in-oil combustible fuel will contain,for example, the maximum amount of heavy oil for which an oil-fired installation was originally designed, when the coal-in-oil combustible fuel is for use in this manner.
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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
Description
- This invention relates to an in-line,method for the beneficiation of coal and the formation of a coal-in-oil combustible fuel therefrcm.
- It 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 agitating the formed mixture in an aqueous medium to cause agglomeration of the coal particles. The coal particle agglomerates 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-forming particles composed 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 mm) which are sufficiently strong 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 fine, impurity-liberated, balled coal products having an average size no greater than of the order of 3 mm in order that the balls will reasily disperse in oil to form a combustible fuel comprising a coal-in-oil suspension. 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 bv micro-agglomeration" Capes et al, there is descried an in-line, one-stage, agglomerating process for producing micro-agglomerates of coal fines which is particularly useful for minimizing the moisture content of coal-in-oil suspensions for transportation along long distance pipelines. While this process is useful for the purpose for which it was developed, there is still a need for this process to ^e developed further to produce a combustible fuel comprising an impurity-liberated, coal-in-oil suspension wherein the retention of larger amounts of the residual moisture content in the fuel from the original coal-in-water slurry can be achieved together with a more accurate control of the larger amount. One reason for this may be that the residual moisture content of the coal-in-oil suspension explodes in a combustion chamber and this possibly aids in dispersing the oil and coal and thereby improving combustion efficiency.
- 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 efficiency in combustion chambers.
- According to the present invention there is provided 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-liberated coal particles at least as fine as 40 microns weight mean particle size, then
- b) mixing the coal-in-water slurry with a light oil agglomerating liquid additive having a specific gravity of less than of the order of 1 gm/cm3 to micro-agglomerate the impurity-liberated coal particles and to dissociate primarily inorganic impurities and some water therefrom, the light oil agglomerating liquid additive 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 gm/cm3, as agglomerating liquid to produce relatively larger agglomerates comprising an average size no greater than of the order of 3 mm and to dissociate primarily 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 agglomerates with make-up heavy oil adiitive to form a coal-in-oil combustible fuel.
- In the accompanying drawing which illustrates, by way of example, an embodiment of the present invention there is shown a flow diagram of an in-line method for the beneficiation 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 therefrom, comprising:
- a) comminuting coal-in-water,in a wet mill 1, to produce a coal-in-water slurry 2 comprising impurity-liberated coal particles at least as fine as 40 microns weight mean particle size, then
- b) mixing the coal-in-water slurry 2, in three stirring
devices 4 to 6 arranged in cascade, with light oil 8, having a specific gravity of less than of the order of 1 gm/cm3, as agglomerating liquid to micro-agglomerate the impurity-liberated coal particles and to dissociate primarily a large amount of inorganic impurities and some water therefrom, the light oil agglomerating liquid 8 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 2, then - c) separating, on a dewatering
screen 10 the micro-agglomerated, impurity-liberated coal from the dissociated inorganic impurities and water, then - d) mixing the separated, micro-agglomerated, impurity-liberated coal 12, in a stirrer 14, with
heavy fuel oil 16, having a specific gravity greater than of the order of 0.9 gm/cm3, as agglomerating liquid to produce relatively larger agglomerates comprising an average size no greater than of the order of 3 mm and to dissociate primarily 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 % in the relatively larger agglomerates, then - e) separating the relatively larger agglomerates, on a vibrating
screen 18, from the dissociated water and inorganic impurities, and then - f) mixing the separated, relatively
larger agglomerates 20, in amixer 22, with make-up,heavy oil additive 24 to form a coal-in-oil combustible fuel 26. - A
dry pulverizer 28 is used for the initial stage of grinding since this will generally pulverize coal faster and in a smaller equipment volume than with wet methods, although wet grinding may be used throughout, if desired. During pulverization, the coal is ground down to a required particle size sufficient to effect separation or dissociation of coal particles and impurities.' - Coal to be pulverized is fed from a
storage hopper 30 to thedry pulverizer 28 which is swept with air from asupply 32. The swept air, with entrained pulverized coal, is fed from thepulverizer 28 to awet scrubber 34. Water containing the pulverized coal is fed from thewet scrubber 34 to ti.e wet mill 1 while air, which has been scrubbed free from the pulverized coal in thewet scrubber 34, 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 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 be micro-agglomerated is tolerable. With the embodiment shown in Figure 1, a residence time of four minutes was required and so the threemixing devices 4 to 6 were provided. - The
first mixing device 4 is a high shear mixing device and may be a conventional turbine mixer. Thefirst 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 as compared with the
mixing device 4 and are for producing the micro-agglomerates. It should be noted that in different embodiments of the present invention, only one lower, intermediate-intensity mixing device is necessary and in other embodiments 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 light oil agglomerating liquid additive 8 is fed to the
first mixing device 4 from astorage tank 38. - As previously stated the micro-agglomerated, impurity-liberated coal is separated from the dissociated components comprising primarily a large amount of inorganic impurities and some water on the
screen 10, which in this embodiment is a stationary, inclined screen down which the separated, micro-agglomerated, impurity-liberated coal rolls and emerges as micro-agglomerates 12 while the dissociated inorganic impurities and water, designated 40, drain through the screen and are conveyed to a settlingpond 42. A vibrating screen separator or wet cyclone separator could be used at this stage if the micro-agglomerates possess sufficient strength 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-upwater 44 which is fed thereto. Thewater 46 from the settling tank provides feed to thewet scrubber 34, wet mill 1 and thefirst mixing device 4. - - The micro-agglomerates 12 then pass to the mixing device 14 which is also a relatively lower blade speed, intermediate intensity mixing device as compared with the
mixing device 4. - The relatively larger agglomerates are separated from the dissociated water and inorganic impurities on the vibrating
screen 18 because the relatively larger agglomerates have sufficient strength not to break up on the vibratingscreen 18, which is an efficient separator for the purpose. A wet cyclone separator, 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 aportion 52 of the water is returned to the stirrer 14 while the remaining water andinorranic impurities 54 are conveyed to the settlingpond 42. - The reason why the
water portion 52 is returned to the mixing device 14 is to ensure that sufficient water is delivered, with the relatively larger agglomerates, to the vibratingscreen 18 to ensure that the inorganic impurities are thoroughly washed from the relatively larger agglomerates. This substantially reduces the possibility of inorganic impurities being carried over the vibratingscreen 18 with the relatively larger agglomerates.In addition, the water in mixing device 14 would usually be heated to about 60°C to reduce the viscosity of theheavy fuel oil 16. Recirculation ofwater portion 52 avoids loss of thermal energy in discarded hot water. - The
mixer 22, to which the relativelylarger agglomerates 20 are conveyed in this embodiment is a stationary, cylindrical vessel having a mixing device rotating about a horizontal axis. Other types of mixers may also be used such aa, for example, a paddle type mixer. - The coal-in-
oil combustible fuel 26 is stored in an agitated condition in a holding tank 56 from which it is withdrawn by apump 58 at the desired rate for consumption as a combustible fuel in, for example, an electrical power generating installation (not shown). The method can be matched to the desired rate of consumption of the combustible fuel so that the holding tank 56 is merely provided 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 beneficiate coal mined from Minto, New Brunswick, Canada and to form a coal-in-oil combustible fuel therefrom will now be given.
-
- The weight ratio of air to coal fed to the
dry pulveriser 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 designed to be capable of treating 100 Imperial gallons/min. (455 1/min.) of slurry 2, which is equivalent to about 6 tons/hour (5.44 tonnes/ 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 high shear impeller blades, two of which are shown for each group and designated 60 to 63, which tapered radially outwardly towards truncated extremities. The highshear impeller blades 60 and 62 were mounted in an 18 inch (0.46 m)internal diameter tank 64 having a 35 inch (0.89 m) height with anannular baffle 66 between theimpeller blades 60 and 62 and four vertical baffles, two of which are shown and desiccated 68 and 70, equally spaced therearound to enhance their shearing effect on the coal-in-water 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 impeller blades two of which are shown and designated 72 and 74. Theblades 72 and 74 were mounted in a 40 in. (1.02 m) internal diameter vessel having a 40 in. (1.02 m) overflow height with four vertical baffles, two of which are shown and designated 76 and 78, equally spaced around theblades 72 and 74 to enhance their shearing effect. - The dissociated inorganic impurities and water, designated 40, mainly comprised of the order of 96 wt % water and 3 wt % ash and sulphur as the main inorganic impurities together with of the order of 1 wt % unagglomer- ated combustible matter.
- The relatively larger agglomerates produced by mixer 14 comprised of the order of 70 wt % coal, 20 wt % oil and 10 wt % water to which was added sufficient No. 6 fuel oil in the
mixer 22 for the coal-in-oilcombustible fuel 26 to comprise a coal/oil weight ratio of 40/60. - Tests have shown that using apparatus of the type shown in Figure 1, then:
- i) the preferred blade tip speed of the high
shear impeller blades 60 to 63 is in the range of the order of 10 m/sec. to of the order of 30 m/sec. better still of the order of 20 m/sec. 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 liquid are No. 2 fuel oil and diesel oil. Other light oils as agglomerating liquid are, for example, light petroleum fractions, kerosene, 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 oils and coke oven tar.
- The quantity of light oil agglomerating liquid additive usod will depend upon the type of coal being processed and how finely the coal must be ground to produce impurity-liberated coal particles. While 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 desirable thing according to the present invention is that only of the order of up to 20 wt % need be used so that the final coal-in-oil combustible fuel will contain,for example, the maximum amount of heavy oil for which an oil-fired installation was originally designed, when the coal-in-oil combustible fuel is for use in this manner.
Claims (7)
Applications Claiming Priority (2)
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 |
CA340749 | 1979-11-22 |
Publications (3)
Publication Number | Publication Date |
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EP0029712A2 true EP0029712A2 (en) | 1981-06-03 |
EP0029712A3 EP0029712A3 (en) | 1981-11-11 |
EP0029712B1 EP0029712B1 (en) | 1984-07-25 |
Family
ID=4115706
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP19800304161 Expired EP0029712B1 (en) | 1979-11-22 | 1980-11-20 | An in-line method for the upgrading of coal |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP0029712B1 (en) |
CA (1) | CA1117884A (en) |
DE (1) | DE3068727D1 (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2526680A2 (en) * | 1978-12-04 | 1983-11-18 | American Minechem Corp | Low-grade coal or washery waste in aq. suspension - improved by agglomerating coal particles by oil addn., and sepg. from suspended ash |
US4726810A (en) * | 1984-05-23 | 1988-02-23 | 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 |
WO1990012078A1 (en) * | 1989-03-31 | 1990-10-18 | Union Oil Company Of California | Separable coal-in-oil mixtures having controlled sedimentation properties and method for making same |
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 |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4730787A (en) * | 1984-06-19 | 1988-03-15 | The University Of Toronto Innovations Foundation | Method of separating solids by simultaneous comminution and agglomeration |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3665066A (en) * | 1969-11-28 | 1972-05-23 | Canadian Patents Dev | Beneficiation of coals |
FR2323754A1 (en) * | 1975-09-09 | 1977-04-08 | Shell Int Research | Prodn. of coal suspensions in hydrocarbon fuel - by agglomeration from aq. suspension and disintegration in fuel |
-
1979
- 1979-11-22 CA CA000340749A patent/CA1117884A/en not_active Expired
-
1980
- 1980-11-20 DE DE8080304161T patent/DE3068727D1/en not_active Expired
- 1980-11-20 EP EP19800304161 patent/EP0029712B1/en not_active Expired
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3665066A (en) * | 1969-11-28 | 1972-05-23 | Canadian Patents Dev | Beneficiation of coals |
FR2323754A1 (en) * | 1975-09-09 | 1977-04-08 | Shell Int Research | Prodn. of coal suspensions in hydrocarbon fuel - by agglomeration from aq. suspension and disintegration in fuel |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2526680A2 (en) * | 1978-12-04 | 1983-11-18 | American Minechem Corp | Low-grade coal or washery waste in aq. suspension - improved by agglomerating coal particles by oil addn., and sepg. from suspended ash |
US4726810A (en) * | 1984-05-23 | 1988-02-23 | 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 |
WO1990012078A1 (en) * | 1989-03-31 | 1990-10-18 | Union Oil Company Of California | Separable coal-in-oil mixtures having controlled sedimentation properties and method for making same |
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 |
Also Published As
Publication number | Publication date |
---|---|
EP0029712B1 (en) | 1984-07-25 |
EP0029712A3 (en) | 1981-11-11 |
CA1117884A (en) | 1982-02-09 |
DE3068727D1 (en) | 1984-08-30 |
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