Reference to Related Applications.

Reference is made to a related earlier application "Reducing Sulphur Dioxide Emissions from Coal Combustion", published as WO 02/079356A1, the contents of which are hereby incorporated by reference.

Field of the Invention

The present invention relates generally to a method and apparatus for treating coal for reduction of emissions, utilization of coal "fines" and enhancement efficiency of the coal burn and refers particularly, though not exclusively to the pre-combustion treatment of coal to reduce sulphur dioxide, oxides of nitrogen, carbon monoxide, ^" particulates, and mercury, enhancement of efficiency of the burn and provide for the utilization of coal "fines" during coal combustion.

Background of the Invention

Coal is one of the most bountiful sources of fuel in the world. Coal is typically found as a dark brown to black graphite-like material that is formed from fossilized plant matter. Coal generally comprises amorphous carbon combined with some organic and inorganic compounds. The quality and type of coal varies from high quality anthracite (i.e., a high carbon content with few volatile impurities and burns with a clean flame) to bituminous (i.e., a high percentage of volatile impurities and burns with a smoky flame) to sub-bituminous (i.e., a lower percentage of volatile impurities but higher ash and moisture content) to lignite (i.e., softer than bituminous coal and comprising vegetable matter not as fully converted to carbon and burns with a very smoky flame.) Coal is burned in coal-fired plants throughout the world to produce energy in the form of electricity. Over the years it has been recognized that certain impurities in coal can have a significant impact on the types

of emissions produced during coal combustion. A particularly troublesome impurity is sulphur. Sulphur can be present in coal from trace amounts up to several percentages by weight (e.g. 7 percent by weight.) Sulphur may be found in coal in various forms, e.g., organic sulphur, pyretic sulphur, or sulfate sulphur. When coal containing sulphur is burned, sulphur dioxide (SO ₂ ) in the atmosphere has been linked to the formation of acid rain, which results from sulfuric or sulfurous acids that form from SO ₂ and water. Acid rain can damage the environment in a variety of ways, and, in the United States, the Environmental Protection Agency (EPA) has set standards for burning coal that restricts SO ₂ emissions from coal-fired plants.

While coal is produced in the United States in many areas of the country, much of that coal that is easily mined (and therefore inexpensive) often contains high levels of sulphur that result in levels of SO ₂ in the combustion gases greater than allowed by the EPA. Thus, coal fired plants often must buy higher quality coal from mines that may be located long distances from plants and pay significant transportation and other costs. A significant body of technology has been developed over time to reduce the amount of SO ₂ in combustion gases from burning high-sulphur coal.

This technology has involved treatments to coal during pre-combustion, during combustion, and during post-combustion. The most often used process is that during post combustion. However, such treatments have generally not achieved a satisfactory combination of efficacy in reducing SO ₂ emissions and economic feasibility in implementation.

When coal is burned in the presence of air at the burn temperature of modern boilers, the nitrogen from the air forms covalent bonds with oxygen to form oxides of nitrogen (NO and NO ₂ ) or NOx. NOX is a major component of acid rain. Total NOx emissions from coal-fired boilers are about 6.8 million tons/year, equivalent to

an emissions rate of 0.75 Ib/million BTU. NOx reduction technologies have been developed but with disappointing outcomes:

1 ) low-NOx burners;

2) selective catalytic and non-catalytic reduction technologies (SCR); and

3) artificial intelligence-based control systems.

Most coal deposits contain varying amounts of mercury. When the coal is burned much of this mercury is emitted in the flue gas. This mercury is brought back to the earth in rainwater. This contamination of our surface water has allowed toxic concentrations of mercury to accumulate in fish. As a result fish may be unfit for human consumption. At present there is no viable technology available to control mercury emissions.

Summary of the Invention

According to a first preferred aspect there is provided a process for treating coal with high sulphur content for reducing sulphur dioxide emissions when the coal is burned. The method comprises: a) crushing the coal to a predetermined particle size, b) placing the crushed coal in a pressure container for controlled rotation; c) reducing the atmospheric pressure inside the pressure container for further fracturing a portion of the crushed coal by withdrawing fluids from within the crushed coal; d) removing ambient gases from facture planes, pores and crevices of the crushed coal; e) contacting the fractured coal with an aqueous colloid composition with a calcium compound;

f) rotating the pressure container for a period of time to allow the aqueous colloid composition to permeate the pores and fracture planes and crevices of the crushed coal; g) pressurizing the aqueous composition-treated coal in the presence of carbon dioxide for a further period of time for the calcium compound to shift towards a solid state thereby crystallizing in the pores and fracture planes and crevices of the crushed coal to thereby further fracture the coal; and h) allowing the calcium compound to permeate the newly created fractures created by the crystallization of the calcium compound.

The aqueous colloid composition may be an aqueous colloid of silica, aluminium hydroxide or titanium hydroxide; and the calcium compound may be calcium carbonate or calcium hydroxide.

The controlled rotation may be controlled speed of rotation and direction of rotation; and the direction of rotation may be cyclically reversed after a predetermined number of rotations.

The predetermined particle size may have a maximum cross-sectional diameter selected from: less than thirty centimeters, less than five centimeters, in the range 50 microns to 4 millimeters, and in the range three millimeters to four millimeters.

The reduced pressure may be maintained for a time after pressure in the pressure container reaches its minimum. The time may be one hour or 10 to 45 minutes.

The carbon dioxide may be is substantially pure carbon dioxide; and may be at a pressure selected from at least 50 psi, and in the range of 100 psi to 300 psi.

The crushed coal may be immersed in the aqueous colloid composition while the crushed coal is tumbled within the pressure vessel; or may be contacted with the aqueous colloid composition by spraying the crushed coal with the aqueous colloid composition. The aqueous colloid composition may exhibit a pH of: in the range of 11 to 13.5, at least 13.5, and at least 13.8.

The aqueous colloid composition may comprise one or more of: sodium silicate and calcium carbonate, aluminium hydroxide and calcium hydroxide, titanium hydroxide and calcium hydroxide; and may further comprise at least one of: calcium oxide, ammonium chloride, and ammonium hydroxide.

The aqueous colloid composition may comprise about 2% w/v to 40% w/v sodium silicate or aluminium hydroxide, about 15% w/v to 40% w/v calcium carbonate or calcium hydroxide, about 1.5% w/v to 4.0 % calcium oxide, sodium hydroxide and/or calcium hydroxide, ammonium chloride, and /or ammonium hydroxide.

The resulting coal may have sufficient calcium deposited within it to provide a molar ratio of Ca:S of at in the range 0.5 to 4.0; may comprise silica, aluminium hydroxide, or titanium hydroxide, at a level of at least 0.10% by weight; and may have about 0.5 percent to about 5.0 percent by weight calcium or calcium carbonate.

The aqueous silica colloid composition may be supersaturated with calcium carbonate.

The aqueous silica colloid composition may comprise colloid particles in the size range of about 1μm to about 200μm and may comprise calcium ions incorporated

in the colloidal structure. The colloidal particles may exhibit a polymeric structure based on silica and oxygen, aluminium and oxygen, or titanium and oxygen.

The resulting composition may be is generated by flowing through an electrostatic generator. The electrostatic generator may comprise: a closed fluid circuit comprising a generator fluid reservoir, an outlet conduit, a positive displacement pump, and valving mechanisms.

These may be contained within an inflow conduit to the electrostatic chamber. The electrostatic chamber may comprise a coiled conduit and an outflow conduit from the electrostatic chamber which may connect to the inflow conduit of the generator fluid reservoir.

The electrostatic chamber may contain a coiled fluid conduit contained within a sealed transport housing capable of withstanding at least one atmosphere of vacuum, and two pairs of high frequency electrodes. The two pairs of high frequency electrodes may run countercurrent to each other; and may be fed by electrical conduits off of opposite sides of an AC/DC bridge rectifier.

The feeds from the two sides of the bridge rectifier may be passed through a high frequency, high voltage transformer. The sealed transport housing may be evacuated by one atmosphere. The electrostatic generator chamber may be able to be evacuated by one atmosphere, and the evacuation may be maintained for each cycle of the electrostatic generator.

The aqua rigia containing soluble catalytic metals may be slowly added to water circulating in the electrostatic generator. Also, one or more of sodium silicate, aluminium hydroxide or titanium hydroxide, may be slowly added.

The resulting coal may have sufficient calcium carbonate deposited within fractures in the coal in an amount sufficient to provide a Ca:S molar ratio in the range of 0.5 to 4.0.

The sulphur content may be about 0.5 percent to about 7.0 percent by weight and the calcium carbonate, or another calcium compound, deposited within the fractures in the coal may be in an amount sufficient to provide a Ca:S molar ratio of about 1 to 4.

The coal may have a particle size selected from: less than thirty centimeters maximum cross-sectional diameter, less than five centimeters of maximum cross- sectional diameter, in the range 50 microns to 4 millimeters, and in the range three millimeters to four millimeters.

The calcium compound may be deposited within the fractures of the coal in accordance with the above process.

According to a second preferred aspect there is provided a process for producing energy from burning high sulphur coal while reducing the sulphur dioxide content of the emissions from such burning, which process comprises depositing calcium carbonate within fractures in vacuum-fractured coal and burning the resulting calcium carbonate containing high sulphur coal at high temperatures.

A first portion of the circulating solution may be transferred from the electrostatic generator into a blending tank, and a mixture of sodium hydroxide and calcium hydroxide may be added and dissolved into the circulating solution. The circulating solution in the blending tank may be returned to the electrostatic generator.

A second portion of the circulating solution may be subsequently transferred from the electrostatic generator to the blending tank. Calcium carbonate or calcium hydroxide may be added to and slowly dissolved in the circulating solution in the blending tank. The circulating solution in the blending tank may then be returned to the electrostatic generator.

A third portion of the circulating solution may be transferred from the electrostatic generator to the blending tank and a second amount of calcium carbonate or calcium hydroxide may be added to and dissolved in the circulating solution in the blending tank; the circulating solution in the blending tank may then be returned to the generator.

The circulating solution may have a pH of about 11.60.

Additional calcium carbonate and/or calcium hydroxide may be added to the circulating solution in the electrostatic generator to attain a calcium :sulphur molar ratio of 1.5 .

A fourth portion of the circulating solution may be transferred from the electrostatic generator to the blending tank and calcium oxide added and slowly dissolved into the circulating solution in the blending tank. Following this the circulating solution in the blending tank may be slowly added back to the circulating solution in the electrostatic generator.

A fifth portion of the circulating solution may be transferred from the electrostatic generator the blending tank and ammonium chloride or ammonium hydroxide added to and dissolved in the circulating solution in the blending tank. Following

this the circulating solution in the blending tank may be transferred back to the electrostatic generator.

The final pH may be 11.45.

Subsequent to step (h) the crushed and treated coal may be dried in a dryer. The dryer may comprise a double-walled cylinder in which hot water is circulated between the two walls of the double walled cylinder. The hot water may be circulated in a countercurrent flow pattern in a closed space between the two walls of the double walled cylinder. The double walled cylinder may contain normal

Butanol within the closed space between the two walls of the double walled cylinder. The hot water may circulate in countercurrent conduits distributed around the dryer periphery with each conduit extending from a proximal end to a distal end of the double walled cylinder. A surface of an inner wall of the double walled cylinder may have an operational temperature in the range 110 - 130 ⁰ F. The dryer may comprise an auger for moving the coal to the distal end while the coal dries and is pellatized.

According to a third preferred aspect there is provided a method for treating coal containing mercury to reduce mercury emissions when the coal is burned, the method comprising: a) crushing the coal to a predetermined particle size; b) placing the crushed coal in a pressure container for controlled rotation; c) reducing the atmospheric pressure inside the pressure container for further fracturing a portion of the crushed coal by withdrawing fluids from within the crushed coal;

d) removing ambient gases from pores, facture planes and crevices of the crushed coal; e) contacting the fractured coal with an aqueous colloid composition containing one or more of: silica, sodium silicate, sodium hydroxide, titanium hydroxide, aluminium hydroxide, calcium hydroxide, calcium carbonate, calcium oxide, ammonium chloride, and ammonium hydroxide;

T) rotating the pressure container for a sufficient time to allow the aqueous colloid composition to permeate the pores, fracture planes and crevices of the crushed coal; g) pressuring the aqueous colloid composition-treated coal under a carbon dioxide atmosphere for a period of time sufficient for the calcium carbonate to shift towards a solid state thereby crystallizing in the pores and fracture planes and crevices of the coal thereby further fracturing the coal; and h) allowing the aqueous colloid composition to permeate the newly created fractures created by the crystallization of the calcium carbonate.

The coal may be subsequently dried.

The process may further comprise burning the dried coal at a high temperature as a result of which elemental mercury is oxidized into salts of mercury by heat and the aqueous silica colloid composition. The salts of mercury may be removed from flue gas of a coal fired power plant by one or more of: an electrostatic precipitator, adsorbents added to the flue gas, and a bag house. The salts of mercury may be absorbed by ash and are carried into fly ash and bottom ash. The salts of mercury may be retained in the ash in concentrations which account for 5 to 30% of mercury contained in flue gas from the burning coal and/or may be adsorbed to adsorbents including activated carbon and a silica colloidal adsorbent.

A powdered silica adsorbent may be used for fogging an emissions flue from a coal fired power plant proximal to an electrostatic precipitator. The powdered silica adsorbent may allow adsorbent bonding of salts of mercury to the powdered silica colloid adsorbent. The powdered silica adsorbent with the bound salts of mercury may be removed from the emissions by the electrostatic precipitator and the bag house.

The powdered silica adsorbent may be manufactured by the method:

(a) cleaning the electrostatic generator;

(b) adding water to and circulating the water in the electrostatic generator;

(c) adding an organic or inorganic acid.

(d) adding sodium silicate to the water and circulating it in a reservoir of the electrostatic generator;

(e) adding to the water and circulating tripotassiumcitrate;

(f) slowly adding calcium chloride to the water in the reservoir; and

(g) converting to a dry powder in dessicator,

The final pH may be 10.3 and the dessicator may be a rotating, heated, spray dessicator.

The aqueous colloid composition may be converted to a powder form by being dehydrated by spraying a fog of the aqueous colloid composition into a revolving dessicator. Furthermore, the powder form may be rehydrated by feeding the powder form into a blending tank through a chemical feeder, the blending tank comprising an aqueous circuit which comprises the blending tank, a countercurrent electromagnetic oscillator and a circulation pump.

The electromagnetic oscillator may comprise an iron pipe wound with a series of electromagnetic coils separated by insulators, the wiring being such that a series of accelerator coils are firing in opposite directions, and every other coil constitutes a portion of the unidirectional accelerator series of coils of a direction; two sets of coils being powered from opposite directions for generating a two directional electromagnetic accelerator; the two directional countercurrent electromagnetic field oscillates the dry powder with an electromagnetic force which allows reconstitution of the aqueous colloid composition; the countercurrent electromagnetic field oscillator being powered by alternate sides of a bridge rectifier.

According to a fourth preferred aspect there is provided a high sulphur coal comprising at least about 0.5 percent by weight sulphur, wherein the coal is vacuum fractured, and further comprises calcium carbonate or calcium hydroxide deposited within fractures in the coal in an amount sufficient to provide a Ca:S molar ratio in the range of 0.5 to 4.0.

The sulphur content may be about 0.5 percent to about 7.0 percent by weight and the calcium carbonate or calcium hydroxide may be deposited within the fractures in the coal in an amount sufficient to provide a Ca:S molar ratio of about 1 to 4.

The coal may have a particle size of a maximum cross-sectional diameter selected from the group consisting of: less than thirty centimeters, less than five centimeters, in the range 50 microns to 4 millimeters, in the range three millimeters to four millimeters.

The calcium carbonate or calcium hydroxide may be deposited within the fractures of the coal in accordance with the above process.

According to a fifth preferred aspect there is provided a process for producing energy from burning high sulphur coal while reducing the sulphur dioxide content of the emissions from such burning, which process comprises depositing calcium carbonate or calcium hydroxide within fractures in vacuum-fractured coal and burning the resulting calcium carbonate-containing high-sulphur coal at high temperatures.

The coal may be powdered and burned at a temperature of about 2800 ⁰ F to about 3700°F by blowing it into a furnace, mixing it with a source of oxygen, and igniting the mixture.

According to a sixth preferred aspect there is provided a process for producing energy from burning coal while reducing the oxides of nitrogen content of emissions from such burning, which process comprises depositing a colloid compound within fractures in the coal and burning the resulting coal at high temperatures such that the colloid compound and the metal salts provide a catalyst for reduction of oxides of nitrogen to nitrogen and oxygen.

According to a seventh preferred aspect there is provided a process for increasing the energy output from burning coal, the process comprising depositing a colloid compound within fractures in the coal prior to burning and burning the resulting coal at high temperatures with the colloid compound and metallic salts providing catalysts for more complete combustion and more rapid combustion.

The coal may further comprise silica present at a level of at least 0.10% by weight; and the coal may have a particle size of a maximum cross-sectional diameter selected from the group consisting of: less than thirty centimeters, less than five

centimeters, in the range 50 microns to 4 millimeters, and in the range three millimeters to four millimeters. The coal may be burned in a stoker furnace at about 2400 ⁰ F to about 2600 ⁰ F.

Brief Description of the Drawings

For further understanding of the invention, reference should be had to the following detailed description of preferred embodiments, read in conjunction with the following illustrative drawings, where like reference numerals denote like elements.

In the drawings:

Figure 1 is a representation of the chemical equations represented in the synthesis of sodium silicate from silica and alkali;

Figure 2 is a representation of the polymerization of Si (OH)4 when titrated with CaCO3 in a preferred generator with the formation of the silica polymer and the sequestration of calcium (Ca++) ions as well as catalytic metal ions;

Figure 3 is a representation of the structure of silica colloidal particles in which calcium (Ca++)ions catalytic metal ions are sequestered;

Figure 4 is a representation of a double layer of water associated with typical silica colloidal particles;

Figure 5 is a representation of a preferred embodiment of an electrostatic generator;

Figure 6 is a representation of the chemical formulas as they are conceived in: a) the chemistry of bituminous coal combustion with the formation of gases, heat and ash; b) the chemistry of the silica colloid mixture containing calcium carbonate, calcium oxide, water and CO ₂ under pressure; and

c) the chemistry of calcium carbonate, SO ₂ , water and heat during the burn of coal;

Figure 7 is a representation of a process of taking high sulphur, high mercury bituminous coal from rail cars through a pre-preparation and treatment according to a preferred embodiment;

Figure 8 is a cutaway view of a preferred tumbler dryer; Figure 8a is an alternate view of the tumbler dryer of Figure 8; Figure 9 is a representation of a preferred embodiment of a steam plant that processes, burns and converts treated coal to heat energy, emissions, water and ash (including gypsum);

Figure 10 is a representation of a preferred embodiment of a high temperature furnace where treated coal is burned to produce heat energy that can be used to generate power;

Figure 11 is a representation of a embodiment of a research coal fired power plant which contains electrostatic precipitator (ESP) and bag house; and

Figure 12 is a representation of a preferred rehydrator and system for rehydrating dry powder.

Detailed Description of the Preferred Embodiments

As shown in Figure 1, the process includes the following reactions in equilibrium:

1) dissolving silicon dioxide (sand) in a strong alkali solution of sodium or potassium hydroxide. The sand, alkali and water are heated to more than 1000° C. The mixture is more than 27% by weight in concentrated alkali (3 molar to 4 molar) and results in Si (OH) ₄ <→ Si (ONa) ₄ .

2) The active starting ingredient is Si (OH) ₄ that reacts with the alkali o give HSi; O ₃ and water.

3) The HSI; O ₃ form SiO ₂ and water.

4) The HS; O ₃ reacts with the alkali to form Si O ₃ and water.

In Figure 2, the silica colloid polymer forms particles by decreasing the pH and providing Ca++ ions when calcium carbonate is added to the reaction mix.

Chemistry of Titanium Hydroxide Colloid

Alkoxide - Organic group bound to metal atom through oxygen atom:

1. Ti _(s) + 4CH ₃ CH ₂ OH ₀ ) ^→ Ti(OCH ₂ CH ₃ ) ₄ (s) + 2H2 _(g)

2. Ti(OCH ₂ CH ₃ ) 4 ₍ s) + 4H ₂ O(D ^→ Ti(OH) ₄₍ s)

+

4CH ₃ CH ₂ OH ₀₎

OH OH

3. [Ti(OH) ₄ ]AT(S) — ^→OH - Ti - O - Ti - OH + H ₂ O

* I I

H+ OH OH

I ^H+

OH OH OH i I I

OH - Ti - O - Ti - O - Ti - OH

I I I

OH O O

1 I

OH- Ti -OH OH- Ti - OH

I I

O OH

The titanium colloid sequesters Ca++ therefore making an environment favourable to increasing the solubility of calcium compounds, (s) = solid (I) = liquid (g) = gas

Chemistry of Metal Hydroxide

Aluminum or (Cr ³⁺ , Zn ²⁺ ; Sn ²⁺ ) Al (OH) ₃ ( _S ) + Ca8H → Al (OH) ₄ ~ _(aq) or +

NaOH H ⁺

The compounds are soluble in strong acid and strong bases but insoluble at neutral pH. They are capable of behaving as either an acid or base.

The negatively charged AI(OH) ₄ sequesters therefore making an environment favourable to increasing the solubility of calcium compounds

Figure 3 shows the active colloid in which Ca++, and catalytic metal ions are sequestered.

Figure 4 shows the typical double layer of water bound on a silica colloidal particle.

The electrostatic generator 50 is illustrated in Figure 5. The electrostatic generator 50 allows manipulation of the receptor sites on various organic and inorganic polymers by manipulation of the flux rate of the system, and the frequency and intensity of electrical pulses delivered to antennae 25 and 26.

The antenna system 25 receives impulses at, preferably, 50KHz - 100KHz through conductors 7 and 8. The impulses are generated by a high-voltage, high- frequency transformer 16 powered through conductors 17 from one side of bridge rectifier 18, powered by main voltage AC through conductors 19 and 20. The antenna system 26 receives impulses at 50KHz - 100KHz through conductors 9 and 10. The impulses are generated by high-voltage, high-frequency transformer

11 powered through conductors 12 from one side of a bridge rectifier 13 powered by mains voltage AC conductor 14 and 15, powered by the same AC power source 27 as conductors 19 and 20. Therefore, the two paired antenna systems 25, 26 are powered in an alternating fashion 60 times per second counter current to each other.

The generator 50 of Figure 5 is prepared for operation by placing fluid in the reservoir 24. Generator 50 is placed in a one-atmosphere vacuum by opening valve 4, turning on vacuum pump 1 , and pulling the vacuum through conduit 2 and out through conduit 3. When complete, and the vacuum of one atmosphere has been reached, valve 4 is closed.

Fluid pump 22 is turned on at an appropriate rate such as, for example, 20 gpm. Fluid is drawn from reservoir 24 through conduit 23 and pushed through value 21 by pump 22 through coil 6 and out through conduit 28 back into reservoir 24. The cycle repeats continuously.

The detail manufacture of the product entails the following, but not limited to: forty two (42) gallons of good quality water are placed into the reservoir 24. The generator 5 is placed into a vacuum and the power 27 is switched on to the electrostatic generator. Water circulates through the generator 50 at 20gmp at a pressure in the range 10-20 psi pressure for 20 minutes with the pH being held in the range 5-6. Aqua rigia containing catalytic metals is slowly added during the 20 minute period. The quantity is preferably 20ml. Eight liters (8L) of sodium silicate, aluminium hydroxide or titanium hydroxide about 27% are slowly added to the generator 50 during the 20 minutes period and circulated for 45 minutes. The pH is 11.0.

Five (5) gallons of the solution are removed from the generator circuit into a blending tank. A mixture of Na OH / Ca (OH) ₂ to a total weight of 15 pounds is added to the blending tank and dissolved over a 10-minute period. A further 2.5 gallons of good quality water is added to the solution in the blending tank and the resultant solution is slowly fed back into the generator 50 and allowed to circulate for 90 minutes. The pH is 11.0 to 12.0.

Approximately 20 gallons of the solution are pumped from the generator into the blending tank 24a and 51.3 pounds of calcium carbonate or calcium hydroxide are added and dissolved. The resultant solution is slowly pumped back into the generator 50 over a 20 minute period with the pH being about 11.60. The solution is allowed to circulate for 20 minutes and 20 gallons of the solution circulating in generator 50 are transferred back into the blending tank 24a. Another 51.3Ib. of calcium carbonate is added to the solution in the blending tank 24a and dissolved, then the solution is pumped back into the solution generator 50 over a 20 minute period and circulated for 20 minutes. The pH of 0.5 or greater remains at 11.60.

Additional calcium carbonate and/or calcium hydroxide is added to attain a calcium/sulphur ratio (moles of calcium in the solution divided by the moles of sulphur in the coal to be treated). A further 20 gallons of fluid from the generator

50 are transferred to the blending tank 24a and 5.5 pounds of calcium oxide ("quick lime") is slowly added to the solution in the blending tank. The resultant solution is added back to the generator 50 and circulated for 30 minutes. The pH is now approximately 11.57.

About 20 gallons of solution from the generator 50 is pumped into the blending tank and 1.0 Kg of ammonium chloride (NH ₄ CI) is slowly added, with mixing. It is then transferred back to the generator over a 10 minute period and circulated for 30 minutes. The pH is now 11.4. The solution is placed in a barrel and the final pH

T/SG2005/000197

20

measured, as is the specific gravity.

The aqueous colloid composition of silica, aluminium hydroxide or titanium hydroxide therefore comprises about 2% w/v to 40% w/v sodium silicate, aluminium hydroxide or titanium hydroxide; about 15% w/v to 40% w/v calcium carbonate; about 1.5% w/v to 4.0 % calcium oxide, sodium hydroxide and/or calcium hydroxide, and ammonium chloride. Furthermore, the aqueous colloid composition is supersaturated with calcium carbonate. Also, the aqueous colloid composition comprises colloid particles in the size range of about 1μm to about 200μm. Preferably, the colloidal particles exhibit a polymeric structure based on silica and oxygen. The aqueous colloid composition is generated by flowing through the electrostatic generator 50 with the antennas 25, 26 being in operation as is described above.

Figure 6 represents a summation of the chemistry. The chemistry remains the same regardless of the nature of the colloid. The details and sequence of chemical reactions will be discussed below at the appropriate place and sequence.

In (b)(ii), the CO _2a q, hydrated CO ₂ is the dominant form in solution. The colloid sequesters CO ₂ and therefore allows more CO ₂ to go into solution. Also, for CO ₂ +H ₂ O, the CO ₂ is under pressure.

For (b)(ii) the increased concentration of CO ₂ under pressure crystallizes the Ca++CO ₃ into crystalline CaCO ₃ which fractures and locks the CaCO ₃ into the parts of the coal. This results from a conversion of CaO to CaCO ₃ under high pressure of CO ₂ . Fracturing of the coal ultimately involves a process referred to as "Heterogeneous Equilibrium". They are the equilibria that involve solids, liquids and dissolved species as well as gases. One example of this type of equilibria involves a chemical reaction, the decomposition of calcium carbonate in the formation of lime from limestone:

CaCO3(S)«- ^» CaO(S) + CO2(g)

If calcium carbonate (limestone) is heated, it decomposes into calcium oxide (lime) and carbon dioxide. The reverse reaction is favored at sufficiently high pressures of carbon dioxide. The two pure solids do not enter the equilibrium expression, and the equilibrium constant reduces simply to the partial pressure of carbon dioxide.

As is shown in Figure 7, coal is brought to the steam generator plant via any suitable means including, but not limited to, conveyors or, as shown, train cars (102). It is dumped in the coal hopers (103) underneath the control tower (100). The coal is then fed onto conveyor belt (104) and transported to coal breakers (108) and (109) via conduit (105). The low quality reject and debris are transported to reject piles (111) and (112) via conduits (106) and (107). After breaking or crushing the coal is preferably of a particle size having a maximum cross-sectional diameters in the range 50mm to 30cm, preferably 50mm to 5cm, more preferably 50mm to 4mm, and most preferably 3mm to 4mm.

Coal is released from the breakers 108 and 109 and falls onto conveyor (110) which dumps it into conduit (114) then to conduits (113) and (114a) which carries the coal to hamper (115) which dumps the coal through a pressure hatch (117) into the tumbler pressure tank (116).

The flow of coal continues until a specified amount such as, for example, when the tank 116 is 80% full. The tumbler pressure tank 116 then turns a sufficient number of revolutions such as, for example, at least two revolutions, to move the coal away from the pressure hatch (117) toward the distal end via an auger inside the pressure vessel 116. This process is continues until the vessel is 80% full of coal and coal fines.

The tank 116 is then sealed and rotated at a controlled speed and in a controlled manner. For example, the speed may be 6 rpm, and the controlled manner may be two rotations in one direction then reversed for two rotations in the opposite direction. This cycle continues so as to keep the coal evenly distributed in the pressure tank (116).

A 26 inches vacuum is applied for a period of time such as, for example, 20 minutes by a vacuum pump 123 that is operatively attached to the tank 116 through a rotating union (not shown) on the end of the pressure tank 116. This draws out liquid and gasses from the coal and evacuates pores in the coal thereby further fracturing the coal. The vacuum is applied for a predetermined time of, for example, 10 to 60 minutes after the pressure inside tank 116 is minimized. The treatment solution as described above in relation to Figures 1 to 5, synthesized in building (127), is pumped into storage tank (124) via conduit (35), and then is pumped via conduit (34) through conduit (121) and is drawn by the vacuum into tank (116) through the rotating union, when the valve is opened to the vacuum. During the transfer of the treatment solution the pressure tank 116 continues to rotate as described above. The treatment solution may be applied by spraying so as to coat the coal in the tank 116, or by immersion of the coal in the tank within the treatment solution.

The ionized calcium carbonate, calcium oxide, water and the colloid laden with Ca ++ is drawn into the evacuated pores and fracture planes and crevices of the coal.

As the tank 116 continues to rotate, the vacuum is stopped, and valves are opened to allow CO ₂ to flow into tank 116 from tank (26) (see Figure 7). The flow of CO ₂ is via conduit (36), (123), conduit (121) and the rotating union on the end of pressure tank (116). Preferably, the CO ₂ may be substantially pure CO ₂ . A pressure of 50-

300 psi, preferably 100 to 300 psi, is maintained for a required period such as, for example, 15-40 minutes. The CO ₂ is then released to a waste tank 128 via a gas pressure pump 130 and conduit 129. The pressurized CO ₂ allows the calcium carbonate in the treatment solution to shift towards a solid state thereby crystallizing in the pores and fracture planes and crevices of the coal to further fracture the coal. It also drives the calcium carbonate deeper into the fractures. On the following cycle CO ₂ is pumped from the waste tank 124 via conduit 129 prior to taking CO ₂ from the CO ₂ reserve tank 26.

The pressure hatch 117 is then opened and the treated coal falls onto a conveyor 30 over a sump (not shown) that catches any moisture in the coal. The coal dumps with each rotation of the tank 116 as the cylinder 116 is turned in the reverse rotational cycle compared to the loading rotation. The coal is then delivered to a semi lunar conduit or chute 31 which delivers the treated coal to a drying tumbler cylinder 136 of a dryer 32.

The resulting coal before drying has sufficient calcium carbonate or other calcium compound deposited within it to provide a molar ratio of Ca:S in the range 0.5 to 4.0 and comprises silica aluminum or titanium at a level of at least 0.10% by weight. Preferably, the resulting coal has about 0.5 percent to about 5.0 percent by weight calcium or calcium carbonate or other calcium salts.

In Figures 7, 8 and 8a, the drying tumbler cylinder 136 is a double-walled cylinder having inner wall 135 and an outer wall 134 thus forming a gap 133 in which hot water is circulated through dual ports 132 contained in a rotating union 131 in the distal end 130 of the cylinder 136. The double walled cylinder contains normal Butanoi and is heated by counter current heater coils 129, which run the length of the dryer cylinder 136 (one counter current coil per quadrant). This heated surface

of inner wall 135 is preferably at a temperature of 110-130° F. The temperature is of importance for proper formation of coal pellets 128 formed from the treated coal fines. As the wet treated coal is delivered to the drying cylinder 136, the cylinder 136 rotates at a speed sufficient to allow auger-type vanes 126 inside the drying cylinder 136 to push the coal to the distal end 130 of the cylinder 136 in the time required for the coal to dry and become pellatized. The coal 128 spills out through port 37 of Figure 8 onto conveyer 33 of Figure 7 which delivers the coal to conveyor 34 and onto conveyor 35 which delivers coal to the power generation plant as shown in Figure 9.

In Figure 8A the port 37 is shown in the centre of the cylinder 136 and may be made of a transparent material. Rollers 125 mounted in frames 122 are used to assist, control and/or drive cylinder 136.

Referring to Figure 9, the treated coal is carried to the furnace 121 where it is burned. The burning coal heats water to steam 120, which drives turbines 119. The turbines 119 in turn drive electric power generators 118 that send power over the transmission lines 51. Condensers 52, 53 and transformers 54 are also provided.

Alternatively, as shown in Figure 10, the treated coal is delivered to the coal bunkers 210 over conveyor 201 which communicates with conveyor 35 of Figure 7. Coal is metered on demand through scales 209 into pulverizing 207 to produce powdered coal. The powdered coal is directed through coal dust airline 205 and into furnace 204 though fuel injection nozzles 203 and is blown into the furnace 204 where it ignites into an intense swirling fire that burns at about 2800 " F - 3500 ⁰ F.

At the time of the burn, calcium carbonate, calcium oxide, calcium hydroxide, water and sulphur dioxide react in the intense heat to form greater quantities of gypsum (Ca SO ₄ -2H ₂ O) and lime, which remain in the ash. They have value for cement and may be removed for this use from ash bin 206.

The catalytic metals on the colloidal surfaces and combustion surfaces provides a catalytic surface to enhance the coal burn efficiency such that significantly more BTU output per pound is attained. The catalytic surface also oxidizes CO to CO ₂ , energy and water. The catalytic effect reduces nitrous oxide to nitrogen and oxygen. Therefore, high sulphur coal may be burned with increased BTU output and greatly reduced emissions along with improved quality of combustion products.

The treatment solution when applied to coal prior to combustion induces the conversion of elemental mercury to mercury salts of chloride, sulfate and nitrates. These salts are more easily absorbed by agents such as activated charcoal and the silica colloid/calcium chloride powder and/or liquid.

The treatment fluid oxidizes elemental mercury during the combustion process to salts of mercury. Some of the mercury salts are adsorbed to the ash and are carried into the fly ash and bottom ash. About 15 - 30% of the mercury is removed by this process.

The generator 50 may be cleaned such as by cleaning with detergent and rinsed with water. Approximately 4.2 gallons of water is added to generator 50 after cleaning and it is allowed to circulate for a period such as 20 minutes. The circulation is through electrostatic generator 50 and the pH is approximately 5-6. Approximately, 0.8 gallons (3.040 ml) of sodium silicate or other suitable colloid 27% slowly added over a period such 20 minutes and is allowed to circulate for 45

minutes with the pH being approximately 11.0. The pH may be lowered to 10.2 by titration with organic or inorganic acids. Approximately 0.595 Ib (269.73 gms) of trippotassium citrate is added and allowed to circulate for about 15 minutes. Approximately pH is 11.0. Approximately 0.94 Ib of CaCL2 is slowly added to the fluid in the reservoir until it dissolves. It is then blended with 3 gallons of water such that the pH is 10.31.

The liquid is then converted to a dry powder by use of a rotating, spray, heated dessicator.

The dry powder mercury adsorbent is blended with activated charcoal in various ratios to achieve the maximum adsorbent effect on the reduction of mercury emissions when measured distal to the bag house 52 of Figure 11. A metering device infuses various ratios with the flu gas stream just proximal to the electrostatic precipitator 53 of Figure 11. Also shown in Figure 11 are the induced- draft fan 54, stack 55, fuel gas sample port 56, sampling cyclone 57, heat exchangers 58, probe banks 59 and 60, forced draft fan 61 , the apparatus 200 of Figure 10, combustor 62, slurry fuel feed system 63, air feed 64, flue gas sample ports 65 and 66, and bypass cyclone 67.

The aqueous treatment solution, as described with reference to Figures 1 to 5 may be dehydrated to a powdered form for storage and shipment. Free water may be removed but the integrity of the colloid is maintained by the bound water of the colloid. The aqueous treatment solution is dehydrated by a spray revolving drum dessicator. The powder is then collected and stored in bags or containers for shipment.

The dry powder 300 of the treatment solution of the invention is rehydrated by

feeding the dry powder 300 into a blending tank 301 via a chemical feeder 302. The blending tank 301 is a portion of an aqueous circuit which contains the blending tank 301, a counter-current electromagnetic oscillator 303, a circulation pump 304 and conduit 305. The electromagnetic oscillator 307 is constructed by placing an appropriate sized PVC pipe 305 of the circuit through an iron pipe 306 that is wound with a series of electromagnetic coils 307 separated by fibrous ring insulators 308. The wiring is such that a series of accelerator coils formed that fire in opposite directions. Every other coil is a portion of the unidirectional accelerator series of coils.

Therefore, two sets of coils powered from opposite directions generate a two directional electromagnetic environment counter to each other. This counter current electromagnetic field oscillates the dry powder with an electromagnetic force which allows complete reconstitution of the treatment fluid.

The counter current electromagnetic field oscillator 307 is powered by alternate sides of a bridge rectifier 309. The negative lead is connected to the beginning of the coils 110, 11 land the positive lead to the end of the coils 112, 113 in one instance and is switched for the second set of coils.

Whilst there has been described in the foregoing description preferred embodiments of the present invention, it will be understood by those skilled in the technology concerned that many variations or modifications in details of design or construction may be made without departing from the present invention.