A COMPOSITION FOR THE UPGRADING OF LOW-RANKING COAL

FIELD OF INVENTION The present invention relates to a formulation and process to upgrade low rank coals, such as sub-bituminous coal and lignite.

BACKGROUND The listing or discussion of a prior-published document in this specification should not necessarily be taken as an acknowledgement that the document is part of the state of the art or is common general knowledge.

The upgrading of low rank coals, such as sub-bituminous coal and lignite, has been accomplished by a number of methods. In essence, these methods seek to reduce the total moisture content of the coal, leading to an increase in the gross calorific value of the coal. The higher gross calorific value of the upgraded coal means that said coal will provide increased heat energy per unit of coal burnt, leading to a reduction in the amount of coal needed to achieve the desired energy output. In turn this means that the upgraded coal provides a reduction in the release of greenhouse gases (e.g. C0 ₂ ), thereby contributing to a greener environment.

A number of processes have been used in an attempt to upgrade low rank coals. These processes include:

(i) microwave drying of the coal while keeping coal below 90°C;

(ii) evaporative drying using low temperature (25-30°C) waste heat;

(iii) fluidised bed stream drying using low pressure steam at more than 100°C; and (iv) mixing crushed coal with oil, heating the mixture, separating the slurry cake from the oil by centrifuge, the resulting solids are then dried and formed into briquettes.

While the above-mentioned processes improve the quality of the coal, they may not change the underlying nature of the coal, meaning that exposure to moisture may result in the coal degrading once more. Thus, there remains a need for improved methods of upgrading coal.

SUMMARY OF INVENTION

It has surprisingly been found that coal can be permanently upgraded by the introduction of a chemical composition to the coal. Thus, in a first aspect of the invention, there is provided a composition comprising:

a hydrophobic agent selected from one or more of the group consisting of vinyl acetate-ethylene copolymer, silane, and siloxane;

a metal oxide and/or a resin; and

water.

In certain embodiments of the invention, there is provided a composition comprising:

a hydrophobic agent selected from one or more of the group consisting of vinyl acetate-ethylene copolymer, silane, and siloxane;

a metal oxide and/or a resin;

a C _1-6 alcohol; and

water.

In embodiments of the invention:

the hydrophobic agent may be present in an amount of from 0.5 wt% to 25 wt% (e.g. from 1.0 wt% to 20 wt%, such as from 1.2 wt% to 15 wt%, 1.5 wt% to 10 wt%, e.g. from 2.0 wt% to 7 wt%, such as from 4 to 5 wt%);

when present the metal oxide may be present in an amount of from to 0.01 to 5 wt% (e.g. from 0.05 to 1.0 wt%, such as from 0.1 wt% to 0.25 wt%, or 0.75 wt%);

when present, the resin may be present in an amount of from 0.001 wt% to 5.0 wt% (e.g. from 0.015 wt% 0.030 wt% (e.g. 0.025 wt%), or from 3.5 wt% to 4.5 wt% (e.g. 4.0 wt%); and the balance of the composition is water.

In certain embodiments of the invention:

(a) the metal oxide may be selected from one or more of the group consisting of Ti0 ₂ , V0 ₂ , Mn0 ₂ , Fe0 ₂ , CoO, NiO, CuO, and ZnO (e.g. the metal oxide may be ZnO or, more particularly, Ti0 ₂ ); and

(b) the resin may be polyethylene oxide or an acrylic resin, optionally in an amount of from 0.001 wt% to 5.0 wt% (e.g. the acrylic resin may be polyacrylamide (present in an amount of from 0.015 wt% to 0.030 wt% (e.g. 0.025 wt%) or styrene acrylic (present in an amount of from 3.5 wt% to 4.5 wt% (e.g. 4.0 wt%))).

In further embodiments of the invention, the composition may further comprise at least one C _-6 alcohol. For example, the at least one 0 _1-6 alcohol may be present in an amount of from 0.01 wt% to 25.0 wt%. In certain embodiments, the at least one C _1-6 alcohol may be selected from one or more of the group consisting of methanol, ethanol and isopropanol. For example, when the at least one C _1-6 alcohol comprises methanol and/or ethanol, the methanol and/or ethanol are present in a total amount of from 1.0 wt% to 25.0 wt% (e.g. from 4.0 wt% to 20.0 wt%). Additionally or alternatively, the at least one C _1-6 alcohol may comprise isopropanol, which, when present, may be present in an amount of from 0.1 wt% to 15.0 wt% (e.g. from 0.1 wt% to 5.0 wt%, 1.0 wt% to 3.0 wt% or from 0.5 wt% to 2.0 wt%).

In yet still further embodiments, the composition may further comprise a superplasticizer. For example, the superplasticizer may be present in an amount of from 0.010 wt% to 10 wt% (e.g. from 0.010 wt% to 0.10 wt%, from 0.020 wt% to 0.075 wt%, such as from 0.033 wt% to 0.05 wt% or from 0.020 wt% to 5.0 wt%, from 0.033 wt% to 3.0 wt%). In certain embodiments, the superplasticizer may be a lignosulfonate (e.g. calcium lignosulfonate), optionally where the amount of the lignosulfonate in the composition may be from 0.5 wt% to 10.0 wt%, such as from 1.0 wt% to 5.0 wt%, such as 1.5 wt%. In particular embodiments that may be mentioned herein, the superplasticizer may be a polycarboxylate ether, optionally where the amount of the polycarboxylate ether in the composition may be from 0.010 wt% to 0.10 wt% (e.g. from 0.020 wt% to 0.075 wt%, such as from 0.033 wt% to 0.05 wt%). In still further embodiments of the invention, the composition may further comprise:

(a) an ester solvent (e.g. ethyl acetate), optionally in an amount from 1.0 wt% to 5.0 wt%, such as 2.0 wt%; and/or

(b) a peroxide (e.g. hydrogen peroxide), optionally in an amount of from 5.0 w†% to 25.0 wt%, such as from 6.0 wt% to 22.0 wt%, or from 10 wt% to 20 wt%; and/or (c) paraffin oil, optionally in an amount of from 0.05 wt% to 0.25 wt%, such as from 0.1 wt% to 0.2 wt % (e.g. 0.15 wt%)); and/or

(d) a ketone solvent (e.g. acetone), optionally in an amount of from 0.5 wt% to 10.0 wt%, such as from 1.0 wt% to 5.0 wt%, such as 3.0 wt%; and/or

(e) a surfactant, optionally wherein:

(i) the surfactant is present in an amount of from 0.01 wt% to 0.1 wt%, from 0.3 wt% to 1.6 wt%, or from 0.5 wt% to 1.5 wt%; and/or

(ii) the surfactant is a nonionic surfactant (e.g. nonylphenol ethoxylene 9).

In certain embodiments of the first aspect of the invention, the composition does not contain an oil. For example, the composition does not contain paraffin oil, a palm oil (crude or refined) or a cooking oil. In certain embodiments of the invention, the composition may be selected from:

(A) a composition comprising:

from 1.0 wt% to 2.0 wt% (e.g. 1.5 wt%) of vinyl acetate-ethylene copolymer; from 0.02 wt% to 0.03 wt% (e.g. 0.025 wt%) of a resin (e.g. polyacrylamide); from 1.0 wt% to 5.0 wt% (e.g. from 2.0 wt% to 4.0 wt%) of a C _1-3 alcohol (e.g. methanol or isopropanol);

from 5.0 wt% to 15.0 wt% (e.g. 10 wt%) of H ₂ 0 ₂ ;

from 0 wt% to 0.5 wt% (e.g. when present, from 0.05 wt% to 0.2 wt%) of a metal oxide (e.g. Ti0 ₂ );

from 0 wt% to 0.1 wt% (e.g. when present, from 0.05 wt% to 0.2 wt%) of a superplasticizer (e.g. polycarboxylate ether);

from 0 wt% to 1.5 wt% (e.g. when present, 1.0 wt%) of a surfactant (e.g. nonylphenol ethoxylate 9);

from 0 wt% to 5.0 wt% (e.g. when present, 2 wt%) of ethyl acetate; and the balance water;

(B) a composition comprising:

from 5.0 wt% to 25.0 wt% (e.g. from 10.0 wt% to 20.0 wt%) of vinyl acetate- ethylene copolymer;

from 0.05 wt% to 0.20 wt% (e.g. 0.1 wt%) of a metal oxide (e.g. Ti0 ₂ );

from 1.0 wt% to 15.0 wt% (e.g. from 2.0 wt% to 10.0 wt%) of a d _-3 alcohol

(e.g. methanol or isopropanol);

from 0.02 wt% to 0.1 wt% (e.g. from 0.033 wt% to 0.05 wt%) of a superplasticizer (e.g. polycarboxylate ether);

from 0.5 wt% to 1.5 wt% (e.g. 1.0 wt%) of a surfactant (e.g. nonylphenol ethoxylate 9);

the balance water;

(C) a composition comprising:

from 2.0 wt% to 10.0 wt% (e.g. from 5.0 wt% to 7.0 wt%) of a silane or a siloxane;

from 0.01 wt% to 0.1 wt% (e.g. 0.025 wt%) of a resin (e.g. polyacrylamide); from 1.0 wt% to 5.0 wt% (e.g. 2.0 wt%) of a C _1-3 alcohol (e.g. isopropanol); from 0.5 wt% to 1.5 wt% (e.g. 1.0 wt%) of a surfactant (e.g. nonylphenol ethoxylate 9);

from 0 wt% to 0.5 wt% (e.g. when present, 0.1 wt%) of a metal oxide (e.g.

Ti0 ₂ ); and

the balance water;

(D) a composition comprising:

from 1.0 wt% to 3.0 wt% (e.g. 2.0 wt%) of a silane or a siloxane; from 1.0 wt% to 5.0 wt% (e.g. 4.0 wt%) of a resin (e.g. styrene acrylic);

from 0.1 wt% to 1.0 wt% (e.g. 0.5 wt%) of a C _1-3 alcohol (e.g. isopropanol); from 0.01 wt% to 0.1 wt% (e.g. 0.05 wt%) of a surfactant (e.g. nonylphenol ethoxylate 9);

from 0.1 wt% to 0.5 wt% (e.g. 0.25 wt%) of a metal oxide (e.g. Ti0 ₂ );

from 0.1 wt% to 0.2 wt% (e.g. 0.15 wt%) of paraffin oil; and

the balance water; or

(E) a composition comprising:

from 10.0 wt% to 15.0 wt% (e.g. 13.5 wt%) of vinyl acetate-ethylene copolymer and/or a silane or a siloxane (e.g. 13.5 wt% of vinyl acetate- ethylene copolymer, or a combination of 12.0 wt% of vinyl acetate-ethylene copolymer and 1.5 wt% of a silane or a siloxane);

from 2.0 wt% to 5.0 wt% (e.g. 3.0 wt%) of a d _-3 alcohol (e.g. isopropanol); from 15.0 wt% to 30.0 wt% (e.g. 20 wt%) of H ₂ 0 ₂ ;

from 0.5 wt% to 1.5 wt% (e.g. 0.75 wt%) of a metal oxide (e.g. Ti0 ₂ );

from 1.0 wt% to 5.0 wt% (e.g. 1.5 wt%) of a superplasticizer (e.g. calcium lignosulfanate);

from 0.1 wt% to 1.0 wt% (e.g. 0.3 wt%) of a surfactant (e.g. nonylphenol ethoxylate 9);

from 1.0 wt% to 5.0 wt% (e.g. 1.95 wt%) of ethyl acetate;

from 1.0 wt% to 5.0 wt% (e.g. 3.0 wt%) of acetone; and

the balance water.

In certain embodiments of the invention, the composition described herein before may be diluted by a liquid (e.g. water) by a dilution factor of from 1.001 to 30 (e.g. from 1.001 to 20). In a second aspect of the invention, there is provided a use of the composition according to the first aspect of the invention, and embodiments thereof, as an upgrading agent for coal.

In a third aspect of the invention, there is provided a process to upgrade a coal in need thereof, wherein the process comprises the following steps:

(a) a composition according to the first aspect of the invention, and embodiments thereof, is provided as a spraying composition;

(b) a supply of coal in need of upgrading is provided;

(c)

(i) the coal is spread on a planar surface to provide a layer of coal and the layer of coal is sprayed at least once with the spraying composition to provide a treated coal, optionally wherein the layer of coal is agitated; and/or

(ii) the coal is subjected to convection mixing (e.g. in a screw mixer) and coal is sprayed at least once with the spraying composition to provide a treated coal; (d) drying the treated coal at a temperature of from 90 to 150°C and a time of from 30 to 90 minutes (e.g. at a temperature of from 100 to 120°C and a time of from 40 to 60 minutes) and/or stockpiling the treated coal under ambient conditions to provide an upgraded coal. In embodiments of the invention, the composition according to the first aspect of the invention, and embodiments thereof, may be diluted by a liquid before being provided as the spraying composition. For example, the composition according to the first aspect of the invention, and embodiments thereof, may be diluted by a dilution factor of from 1 to 30 (e.g. from 1 to 20). In embodiments of the invention, the liquid used for the dilution of the composition according to the first aspect of the invention, and embodiments thereof, may comprise water.

In embodiments of the invention, the coal in need of upgrading may have an average diameter of equal to or less than 50 mm.

In certain embodiments, when the coal is provided as a layer of coal, the layer of coal may be sufficiently thin to allow the spraying composition to contact substantially all of the surface of the coal. In yet further embodiments, the supply of coal may be provided in a hopper; and/or when the coal is provided as a layer of coal, the layer of coal is spread onto the surface of a conveyor belt. In still further embodiments of the invention, 1 metric ton of coal is sprayed with 3 to 6 litres of spraying composition, such as 5 litres of spraying composition.

DESCRIPTION As mentioned hereinbefore, it has been surprisingly found that a chemical formulation may be used to upgrade coal. Further, it has been found that the use of the chemical composition results in a permanent upgrading of the coal, such that even when the upgraded coal is subjected to soaking in water, the coal remains in the upgraded state, as measured by gross calorific value, amongst other variables. To achieve this, the composition of the current invention is diluted with a liquid (e.g. a liquid comprising water, or which is water) and sprayed onto coal to provide an upgraded coal following reaction of the composition with the coal. Thus, the current invention also relates to a use of the composition described herein to upgrade coal. It will be appreciated that different types of coal may require adjustment of the formula and composition of the chemicals used. Thus, as described above, there is provided a composition comprising:

a hydrophobic agent selected from one or more of the group consisting of vinyl acetate-ethylene copolymer, silane, and siloxane;

a metal oxide and/or a resin; and

water.

In additional embodiments of the invention, there is also provided a composition comprising: a hydrophobic agent selected from one or more of the group consisting of vinyl acetate-ethylene copolymer, silane, and siloxane;

a metal oxide and/or a resin;

a C _1-6 alcohol; and

water. When used herein, the term "comprising" is intended to be open-ended and therefore the compositions may contain additional components. However, it will be appreciated that the term "comprising" encompasses the term "consisting of or "consists essentially of, which respectively relate to the composition only containing the listed ingredients or only the listed ingredients with minor impurities. For the avoidance of doubt, it is explicitly intended that the term "comprising" may be replaced at every instance herein by the terms "consisting of or "consists essentially of and wee versa. In other words, an open-ended listing presented herein may be replaced by a close-ended listing and vice versa.

When used herein, the term "hydrophobic agent" refers to any composition that repels water. A hydrophobic agent according to the current invention may typically provide a surface that has a contact angle of from 100° to 120° in the Sessile Drop Technique. The hydrophobic agent may be present in an amount of from 0.5 wt% to 25 wt% (e.g. from 1.0 wt% to 20 wt%, such as from 1.2 wt% to 15 wt%, 1.5 wt% to 10 wt%, e.g. from 2.0 wt% to 7 wt%, such as from 4 to 5 wt%). Hydrophobic agents that may be mentioned herein include one or more of the group consisting of vinyl acetate-ethylene copolymer, silane, and siloxane.

The composition of the current invention must contain at least one of a metal oxide or a resin. In certain embodiments, both the metal oxide and the resin may be present. In additional embodiments, a C _1-6 alcohol must also be present. The remainder of the composition is water.

When the metal oxide is present, it may be present in an amount of from to 0.01 to 5 wt% (e.g. from 0.05 to 1 wt%, such as from 0.1 wt% to 0.25 wt%, or 0.75 wt%). Metal oxides that may be mentioned herein include one or more of the group consisting of Ti0 ₂ , V0 ₂ , Mn0 ₂ , Fe0 ₂ , CoO, NiO, CuO, and ZnO. Particular metal oxides that may be mentioned herein include Ti0 ₂ and ZnO (e.g. Ti0 ₂ ).

When the resin is present, it may be present in an amount of from 0.001 wt% to 5.0 wt% (e.g. from 0.015 wt% 0.030 wt% (e.g. 0.025 wt%), or from 3.5 wt% to 4.5 wt% (e.g. 4.0 wt%). When used herein, "resin" may refer to a polymeric material. Particular resins that may be mentioned herein include polyethylene oxide and an acrylic resin, which may be used individually or in combination with each other. In embodiments of the invention, the resin may be polyacrylamide (present in an amount of from 0.015 wt% 0.030 wt% (e.g. 0.025 wt) or styrene acrylic (present in an amount of from 3.5 wt% to 4.5 wt% (e.g. 4.0 wt%)). It will be appreciated that the resin is not the same as the hydrophobic agent. The composition may also further comprise at least one Ci_ ₆ alcohol. When present, the at least one C _1-6 alcohol may be present in an amount of from 0.01 wt% to 25.0 wt%. Ci _-6 alcohols that may be mentioned herein include methanol, ethanol and isopropanol, or mixtures thereof. For example, the composition may further comprise:

(a) methanol and/or ethanol in an amount of from 1.0 wt% to 25.0 wt% (e.g. from

4.0 wt% to 20.0 wt%); and/or

(b) isopropanol in an amount of from 0.1 wt% to 5.0 wt% (e.g. 0.5 wt% to 2.0 wt% or from 1.0 wt% to 3.0 wt%). Additionally or alternatively, the composition may also further comprise a superplasticizer. When present, the superplasticizer may be present in an amount of from 0.010 wt% to 10 wt% (e.g. from 0.010 wt% to 0.10 wt%, from 0.020 wt% to 0.075 wt%, such as from 0.033 wt% to 0.05 wt% or from 0.020 wt% to 5.0 wt%, from 0.033 wt% to 3.0 wt%). One class of superplasticizer that may be mentioned herein is the lignosulfonates (e.g. calcium lignosulfonate). When the superplasticizer contains a lignosulfonates, the amount of the lignosulfonate in the composition may be from 0.5 wt% to 10.0 wt%, such as from 1.0 wt% to 5.0 wt%, such as 1.5 wt%. Another class of superplasticizers that may be mentioned hereinare the polycarboxylate ethers. The amount of the polycarboxylate ether in the composition may be from 0.010 wt% to 0.10 wt% (e.g. from 0.020 wt% to 0.075 wt%, such as from 0.033 wt% to 0.05 wt%).

Additionally or alternatively, the composition may also further comprise one of more of a ketone solvent or, more particularly, an ester solvent, a peroxide, paraffin oil, and a surfactant. When present, the ketone solvent may be present in an amount of from 0.5 wt% to 10.0 wt%, such as from 1.0 wt% to 5.0 wt%, such as 3.0 wt%. The ketone solvent may be acetone. When present, the ester solvent may be present in an amount from 1.0 wt% to 5.0 wt%, such 2.0 wt%. The ester solvent may be ethyl acetate. When present, the peroxide may be present in an amount of from 5.0 wt% to 25.0 wt%, such as from 6.0 wt% to 22.0 wt%, or from 10 wt% to 20 wt%. Peroxides that may be mentioned herein include hydrogen peroxide. When present, parrafin oil may be present in an amount of from 0.05 wt% to 0.25 wt%, such as from 0.1 wt% to 0.2 wt % (e.g. 0.15 wt%)). When present, the surfactant may be present in an amount of from 0.01 wt% to 0.1 wt%, from 0.3 wt% to 1.6 wt%, or from 0.5 wt% to 1.5 wt%. In certain embodiments, the surfactant may be a nonionic surfactant. Nonionic surfactants that may be mentioned herein include nonylphenol ethoxylene 9. In certain embodiments that may be mentioned herein, the composition does not contain an oil. For example, the composition does not contain paraffin oil, a palm oil (crude or refined) or a cooking oil. When used herein "cooking oil" refers to an oil comprising a vegetable oil (e.g. olive oil, palm oil, soybean oil, canola oil, pumpkin seed oil, corn oil, sunflower oil, safflower oil, peanut oil, grape seed oil, sesame oil, argan oil, rice bran oil and other vegetable oils) and/or an animal-based oil (e.g. butter, dripping and lard).

Particular compositions that may be mentioned herein include: (A) a composition comprising:

from 1.0 wt% to 2.0 wt% (e.g. 1.5 wt%) of vinyl acetate-ethylene copolymer; from 0.02 wt% to 0.03 wt% (e.g. 0.025 wt%) of a resin (e.g. polyacrylamide); from 1.0 wt% to 5.0 wt% (e.g. from 2.0 wt% to 4.0 wt%) of a C _1-3 alcohol (e.g. methanol or isopropanol);

from 5.0 wt% to 15.0 wt% (e.g. 10 wt%) of H ₂ 0 ₂ ;

from 0 wt% to 0.5 wt% (e.g. when present, from 0.05 wt% to 0.2 wt%) of a metal oxide (e.g. Ti0 ₂ );

from 0 wt% to 0.1 wt% (e.g. when present, from 0.05 wt% to 0.2 wt%) of a superplasticizer (e.g. polycarboxylate ether);

from 0 wt% to 1.5 wt% (e.g. when present, 1.0 wt%) of a surfactant (e.g. nonylphenol ethoxylate 9);

from 0 wt% to 5.0 wt% (e.g. when present, 2 wt%) of ethyl acetate; and the balance water; (B) a composition comprising:

from 5.0 wt% to 25.0 wt% (e.g. from 10.0 wt% to 20.0 wt%) of vinyl acetate- ethylene copolymer;

from 0.05 wt% to 0.20 wt% (e.g. 0.1 wt%) of a metal oxide (e.g. Ti0 ₂ );

from 1.0 wt% to 15.0 wt% (e.g. from 2.0 wt% to 10.0 wt%) of a C _1-3 alcohol (e.g. methanol or isopropanol);

from 0.02 wt% to 0.1 wt% (e.g. from 0.033 wt% to 0.05 wt%) of a superplasticizer (e.g. polycarboxylate ether);

from 0.5 wt% to 1.5 wt% (e.g. 1.0 wt%) of a surfactant (e.g. nonylphenol ethoxylate 9);

the balance water; a composition comprising:

from 2.0 wt% to 10.0 wt% (e.g. from 5.0 wt% to 7.0 wt%) of a silane or a siloxane;

from 0.01 wt% to 0.1 wt% (e.g. 0.025 wt%) of a resin (e.g. polyacrylamide); from 1.0 wt% to 5.0 wt% (e.g. 2.0 wt%) of a C _1-3 alcohol (e.g. isopropanol); from 0.5 wt% to 1.5 wt% (e.g. 1.0 wt%) of a surfactant (e.g. nonylphenol ethoxylate 9);

from 0 wt% to 0.5 wt% (e.g. when present, 0.1 wt%) of a metal oxide (e.g.

Ti0 ₂ ); and

the balance water; a composition comprising:

from 1.0 wt% to 3.0 wt% (e.g. 2.0 wt%) of a silane or a siloxane;

from 1.0 wt% to 5.0 wt% (e.g. 4.0 wt%) of a resin (e.g. styrene acrylic);

from 0.1 wt% to 1.0 wt% (e.g. 0.5 wt%) of a C _1-3 alcohol (e.g. isopropanol); from 0.01 wt% to 0.1 wt% (e.g. 0.05 wt%) of a surfactant (e.g. nonylphenol ethoxylate 9);

from 0.1 wt% to 0.5 wt% (e.g. 0.25 wt%) of a metal oxide (e.g. Ti0 ₂ );

from 0.1 wt% to 0.2 wt% (e.g. 0.15 wt%) of paraffin oil; and

the balance water; or a composition comprising:

from 10.0 wt% to 15.0 wt% (e.g. 13.5 wt%) of vinyl acetate-ethylene copolymer and/or a silane or a siloxane (e.g. 13.5 wt% of vinyl acetate- ethylene copolymer, or a combination of 12.0 wt% of vinyl acetate-ethylene copolymer and 1.5 wt% of a silane or a siloxane);

from 2.0 wt% to 5.0 wt% (e.g. 3.0 wt%) of a C _1-3 alcohol (e.g. isopropanol); from 15.0 wt% to 30.0 wt% (e.g. 20 wt%) of H ₂ 0 ₂ ;

from 0.5 wt% to 1.5 wt% (e.g. 0.75 wt%) of a metal oxide (e.g. Ti0 ₂ );

from 1.0 wt% to 5.0 wt% (e.g. 1.5 wt%) of a superplasticizer (e.g. calcium lignosulfanate);

from 0.1 wt% to 1.0 wt% (e.g. 0.3 wt%) of a surfactant (e.g. nonylphenol ethoxylate 9);

from 1.0 wt% to 5.0 wt% (e.g. 1.95 wt%) of ethyl acetate;

from 1.0 wt% to 5.0 wt% (e.g. 3.0 wt%) of acetone; and

the balance water. As discussed below, the above compositions may be used as-is, or they may be further diluted (e.g. with water). These diluted compositions also form part of the current invention. For example, the compositions described hereinbefore may be diluted by a liquid (e.g. water) by a dilution factor of from 1.001 to 30 (e.g. from 1.001 to 20).

The compositions described hereinbefore are useful in upgrading coal. As such, the current invention also relates to a use of the compositions as described herein as an upgrading agent for coal. For example the coal in question may be a coal in need of upgrading, such as a low rank coal. Low rank coal that may be mentioned herein include sub-bituminous coal and lignite.

The use of the composition to upgrade a coal in need thereof is accomplished by a method. Thus, there is provided, a process to upgrade a coal in need thereof, wherein the process comprises the following steps:

(a) a composition as described hereinbefore, and embodiments thereof, is provided as a spaying composition;

(b) a supply of coal in need of upgrading is provided;

(c)

(i) the coal is spread on a planar surface to provide a layer of coal and the layer of coal is sprayed at least once with the spraying composition to provide a treated coal, optionally wherein the layer of coal is agitated; and/or

(ii) the coal is subjected to convection mixing (e.g. in a screw mixer) and coal is sprayed at least once with the spraying composition to provide a treated coal; (d) drying the treated coal at a temperature of from 90 to 150°C and a time of from 30 to 90 minutes (e.g. at a temperature of from 100 to 120°C and a time of from 40 to 60 minutes) and/or stockpiling the treated coal under ambient conditions to provide an upgraded coal.

In step (a) the composition disclosed hereinbefore, may optionally be diluted by a liquid before being provided as the spraying composition. For example, the liquid used for the dilution of the composition may comprise water.

When the composition described hereinbefore is diluted by a liquid before being provided as the spraying composition, said composition may be diluted by a dilution factor of from 1 to 30 (e.g. from 1 to 20). For the avoidance of doubt, a dilution factor of 1 represents no dilution, while a dilution factor of 30 represents a dilution of 1 :29 (v:v) of the compositiomdilution liquid, which assuming that the numbers represents litres provides a total liquid amount of 30 litres. Other dilution factors contained within the scope of the range may be derived accordingly. While the process may be used with any reasonably size coal pieces, the process may be particularly suitable for use where the coal in need of upgrading has an average diameter of equal to or less than 50 mm. It is noted that most coal sold commercially has an average diameter of equal to or less than 50 mm. When coal is provided as a layer of coal, the layer of coal may be spread sufficiently thin to allow the spraying composition to contact substantially the entire surface of the coal. This thin layer of coal may be achieved by simply spreading the coal onto a surface by hand (as described in the examples), or by the use of any other suitable means to achieve such a thin layer of coal (e.g. a conveyor belt). It will be appreciated that the currently described process may be readily applied on an industrial scale with very little need to retrofit existing coal processing equipment. For example, the coal may be supplied in a hopper in contact with a conveyor belt, such that the coal leaving the hopper is spread onto the surface of a conveyor belt in a manner suitable for use in the process of the current invention. The composition as described hereinbefore may be provided as a diluted spraying composition, with a dilution factor of 1:20 (diluent being water), where 1 metric ton of coal may be sprayed with from 3 to 6 litres of the diluted spraying composition to provide the desired effect. As such, embodiments of the invention described herein relate to a process wherein 1 metric ton of coal is sprayed with from 3 to 6 more litres of the spraying composition, such as 5 litres of the spraying composition. Said spraying composition may be undiluted or diluted with a liquid.

Further aspects and embodiments of the invention will be described in relation to the examples. EXPERIMENTAL SECTION

Materials and Methods

Chemical Compositions

Various chemical compositions were prepared by mixing the components in the amounts indicated below (in wt%) in Table 1 to form approximately 1 L of a solution.

Table 1a

Formula No. (wt %)

Ingredients M3a M3b M3c L1a Lib J15

Methanol

Ethyl Acetate

Titanium dioxide 0.1 0.1 0.1 0.25

Polyacrylamide 0.025 0.025 0.025

Isopropyl alcohol 2 2 2 2 2 0.5

Hydrogen peroxide 10 10 10

Vinnapas™ 536 ED

1.5 1.5 1.5 10 10

Silres™BS 1001

2

Polycarboxylate ether 0.033 0.033 0.033 0.033

Nonylphenol ethoxylate 9 1 1 1 1 1 0.05

Parafin oil 0.15

Styrene acrylic 4

Water 85.34 85.44 85.38 86.87 86.97 93.05

Table 1b

Table 1c Vinnapas ^{I M} 536 ED (55% solid), Vinnapas™ 8181 and Siles™ BS1001 (50% solid) were purchased from Wacker-Chemie Ag. Polyacrylamide was purchased from an Indonesian manufacturer under the trade name Aquaklir. Polycarboxylate ether was purchased from Permin under trade name Peramin™ CONPAC 149S. Nonylphenol ethoxylate 9 was purchased from The Dow Chemical Company. Calcium lignosulfonate was purchased from PT Ligno Speciality Chemicals. Silicon emulsion used is Silicon Emulsion S233KTL manufactured by Matapel Chemicals in Indonesia.

Analytical Tests

To determine the coal contents under ideal conditions, the following tests were conducted. Total moisture content was determined using ASTM D 3302 / D 3302M-12. Inherent moisture content was determined using ASTM D 3173-11. Ash content was determined using ASTM D 3174-11. Volatile matter was determined using ASTM D 3175-11. Fixed carbon was determined by calculation (Fixed Carbon in = 100% - % (inherent moisture) -% (ash) - % (volatile matter)). Total sulfur content was determined by ASTM D 4239-12. Gross calorific value (Kcal/kg) was determined using ASTM D 5865-11a. In each of the above tests, the coal samples were oven dried and the results are reported in the table below using the abbreviation ADB (air dried basis). These values represent the maximum potential of the coal as determined under ideal laboratory conditions. As coal used in a commercial setting is not under such ideal conditions, the above tests were conducted on the samples as received without the oven-drying step. This provides a more realistic value of the coal that would be received by a customer and is referred to in the following tables with the abbreviation AR (as received) to denote when the measurement has been done without the oven drying step of the relevant protocols.

The Hardgrove Grindability Index (HGI) is measured in accordance with ASTM D 409/D 409M-11ae1. Examples

Example 1

Each of the chemical compositions M1, M3, L1, L2, L2a, L2b, M3a, M3b, M3c, L1a, Lib and J15 were diluted using 1 litre of chemical composition to 19 litres of water to form a spraying composition having a total volume of 20 litres.

Coal samples were provided that had an average diameter of less than or equal to 50 mm (approximately 10% of the coal fragments in each sample having a diameter of over 50 mm in size), the size being achieved by breaking larger lumps of coal into smaller pieces with a hammer. This size was chosen as it most closely resembles the type of coal that is sold commercially.

Each spraying composition was sprayed onto two separate coal samples in need of upgrading. The coal samples (4-5 kg) were each spread evenly on separate plastic sheets and approximately 200 mL of the diluted chemical composition was applied to each sample. Each of the treated samples were then dried for 22 hours, of which 5 hours was in direct sunlight. All dried samples were weighed and then dried under the sun for a further 4 hours and weighed again.

For each chemical composition, one of the dried samples was sealed and then tested under laboratory conditions to determine the quality of the coal, while the other sample was subjected to a hydrophobicity test. Laboratory Results of Sealed Samples

The weight recorded and the laboratory test results are tabulated in Tables 2 and 3, respectively, for each of the sealed samples treated with the various chemical compositions. Each Table is then divided into two sections according to the date the sample was prepared (either Day A or Day C). Date of sample preparation Day A

Sample No. MEC 1 MEC 3 MEC 5 MEC 6

Chemical composition used

(Formula No.) 1 M3 L1 L2

Weight of original sample (kg) 4.817 4.981 4.893 4.719

Weight of treated sample after 18

hours (left overnight into Day B,

total of 5 hours sun on Day A and

Day B before weight measured) (kg) 3.800 4.556 3.763 3.739

% weight lost -21.11 -8.53 -23.09 -20.77

Weight of treated sample after

further 6 hours (4 hours of

additional sun on Day B) (kg) 3.360 4.21 3.305 3.229

Total % weight lost -30.25 -15.46 -32.45 -31.57

Table 2a

On Day A through to Day B, the average temperature was 31 °C and relative humidity was from 60% to 65%. On Day B, the average temperature was 32°C and relative humidity was about 65%.

Table 2b On Day C, the average temperature was 30°C and relative humidity was about 70%. On Day D, the average temperature during until 2 pm was 30°C with a relative humidity of about 65%, from 2 pm onwards it rained heavily and the average temperature was 29°C, with a relative humidity of about 85.

As shown in Table 2, all of the treated samples show a drop in weight after drying. In addition, the drop in weight was larger for the samples that were prepared on Day A than on Day C. It is speculated that this was due to different weather conditions (e.g. temperature, humidity and precipitation), which resulted in differing levels of evaporation. To avoid the differing levels of evaporation, the treated coal may be treated in an oven for a defined period of time to provide a uniform result.

Table 3a

In Table 3, a sample of untreated and non-upgraded coal was also tested for comparison purposes. As shown, coal samples treated with one of the various chemical compositions results in a significant increase in the Gross Calorific Value of the treated coal (especially as received coal) and a noticeable decrease in the Total Moisture content. Without wishing to being bound by theory, it is believed that the chemical composition of the current invention reacts with the water in the surface pores of the coal to provide a barrier that allows the water in the interior of the coal to exit, while not allowing water to re-enter the coal. This results in a structural change in the coal that results in an increase in the calorific value of the coal based on the following formula:

(100 - total moisture)

Calorific value (AR Basis) in Kcal/kg = X gross calorific value (ADB).

(100 - inherent moisture)

By reducing the total moisture of the coal, and with the inherent moisture remaining the same, the nett calorific value (on an as received basis, which relates to the heat value of the coal obtained by a user of the coal) is increased or upgraded to a higher heat value. Table 3 also shows that the ash value and the internal moisture of the treated samples is usually 1 to 2 wt % lower than untreated coal, which also results in a perceived improvement in coal quality. Hydrophobicity Test

Each of the remaining dried and treated samples were individually poured into a pail of water (at least 5 inches deep), so that the sample was entirely submerged, and soaked for 3 hours. Each of the soaked samples were individually spread on separate plastic sheets and dried under ambient conditions. The sample was weighed at various points of time after removal from the pail of water (as indicated in Table 4). Each Table is then divided into two sections according to the date the sample was prepared (either Day A or Day C).

Date of sample preparation Day C

Sample No. L2a2 L2b1 M3a2 M3b1 L1a2 J15

Chemical composition used (Formula No.) L2a L2b M3a M3b L1a J15

Weight of original sample (kg) 4.954 4.912 4.956 4.956 4.926 4.855

Weight of treated sample after 40 hours

without sun (kg) 3.483 4.541 4.825 4.631 4.455 4.377

% weight lost/gain -29.69 -7.55 -2.64 -6.56 -9.56 -9.85

Hydrophobicity of the sample sprayed with

chemical composition:

H - Hydrophobic

NH - Not hydrophobic H H H H H H

Table 4b

Table 4 allows a comparison of the hydrophobicity test results between samples treated with chemical compositions M1 and M3, respectively. Sample MEC 3, which was treated with chemical composition M1, was found to be hydrophobic. In contrast, sample MEC 1 was treated with chemical composition M3 and was found to be not hydrophobic. As the only difference between chemical compositions M3 and M1 is that chemical composition M3 contains a hydrophobic agent according to the current invention (Vinnapas™ 536 ED), this suggests that a the presence of such a hydrophobic agent is essential to providing an upgraded coal with the good properties described above.

Example 2

Chemical composition J15 was diluted using 1 part chemical composition to 19 parts of water, which was stored in a tank to be sprayed to coal in need of upgrading.

A batch of coal weighing approximately 6000 metric tons was provided. The coal was crushed to a size identical to that of Example 1 and transported by a conveyor belt with a width of approximately 1 meter at a speed of 200 metric tons per hour. During the transport, the spraying composition was sprayed onto the coal, where approximately 5 litres of spraying composition was applied to 1 metric ton of coal. The treated coal was stockpiled for 3 days under ambient conditions for drying. Following which, the dried coal was sent for testing and the test results are compared with that of an untreated coal in Table 5. Coal before

Sample Description

upgrade Coal after upgrade

Test standards used ADB AR ADB AR

Gross calorific value (in Kcal/kg)

4838 3340 5097 4487

Total moisture (%) - 40.82 - 23.87

Inherent moisture (%) 14.27 - 13.52 -

Ash (%) 10.65 7.35 6.19 5.45

Volatile matter (%) 42.26 29.17 43.84 38.59

Fixed carbon (%) 32.82 22.66 36.45 32.09

Total Sulphur (%) 0.6 0.41 0.44 0.39

Hardgrove Grindability Index -

Table 5

As shown in Table 5, which is similar to the results in Example 1 , the coal treated with chemical composition J15 results in an increase in the Gross calorific value (as received coal) of the treated coal from 3340 Kcal/kg to 4487 Kcal/kg.

The result reported above was obtained when the coal was dried under ambient weather conditions, in this case the conditions were generally sunny with no precipitation. In contrast, a similar batch of upgraded coal was prepared in accordance with the example above, except this time the ambient weather conditions involved a significant amount of precipitation Even in these less than ideal ambient conditions, the gross calorific value (AR) of the upgraded coal had improved to 4200 Kcal/kg, as compared to 3340 Kcal/kg for coal that had not been upgraded. Example 3

Each of the chemical compositions ML1 and ML2 were prepared and used in keeping with the method outlined in Example 1 to form two treated coal specimens. These coal specimens were compared to an untreated sample of coal from the same batch as tested. Tables 6 and 7 provide data on the untreated coal sample and the treated coal samples. S/n Description Untreated ML1 ML2

1 Sample immediately after 6.55 8 9.05

treatment (or no treatment)

2 22 hours later (4 hours sun) - 7.9 8.5

% weight lost - 1.25 6.08

3 48 hours (1 hour sun: raining 6.50 7.00

day)

% weight lost - 18.75 22.65

4 72 hours (4 hours sun) - 5.95 6.40

% weight lost - 25.63 29.28

Table 6

Table 7

As shown, compositions ML1 and MI2 both improve the original coal samples and prevent the ingress of moisture into the upgraded coal, even in damp conditions (e.g. during and following rain).