WO2008147076A1

WO2008147076A1 - High concentration nanoparticle size magnesium fuel additive for fossil fuel burning apparatus

Info

Publication number: WO2008147076A1
Application number: PCT/KR2008/002881
Authority: WO
Inventors: Wayne Peck; Don Poscente
Original assignee: Wayne Peck; Don Poscente
Priority date: 2007-05-30
Filing date: 2008-05-23
Publication date: 2008-12-04
Also published as: CN101314744A; KR100768536B1; KR20070082069A

Abstract

A magnesium nanoparticle size fuel additive composition for mixing with fossil fuels prior to their combustion in a fuel burning apparatus or injection into a boiler firebox immediately after combustion comprises at least one overbase complex of a magnesium salt and an organic acid complexing agent. The fuel additive composition, when combusted in the fuel burning apparatus, synergistically generates billions of particles of magnesium oxide in situ that adsorb sulfur oxides in various forms from the time they are first formed.

Description

HIGH CONCENTRATION NANOPARTICLE SIZE MAGNESIUM FUEL ADDITIVE FOR FOSSIL FUEL BURNING

APPARATUS

Technical Field

[1] The present invention relates generally to fuel additive compositions and, more particularly to a nanoparticle size fuel additive composition comprising at least one overbase complex of a magnesium salt and an organic acid complexing agent to be mixed with coal, crude oil or heavy fuel oil prior to the combustion process in a fuel burning apparatus or injected into a boiler firebox immediately after combustion which, when combusted, synergistically generates billions of particles of magnesium oxide in situ that adsorb sulfur oxides in various forms from the time they are first formed. Background Art

[2] A growing concern with the safe use of coal, crude oil or residual heavy fuel oil is the level of emissions of elements considered to be toxic in the environment. One element that has proven to be most troublesome is sulfur and its oxides.

[3] Sulfur combusts in the flame, forming primarily sulfur dioxide. A proportion of the sulfur dioxide continues on to form sulfur trioxide with additional oxygen present to support combustion. When enough heat is removed from combustion gases this sulfur trioxide condenses with water vapor to form sulfuric acid. This acid is corrosive to iron metallurgy and is also one of the major contributors to acid rain.

[4] In order to reduce the emission of hazardous substances, many industries are obliged to clean up their flue gases before ventilation in the environment. Depending on the nature of the pollutant, various techniques have been developed to clean up the flue gas. For example, fly ash can be removed with electrostatic precipitators (ESP), fabric filters (FF) or wet scrubbers. Acid gases are mostly bound to alkaline compounds, either in a (semi-) dry system with spray dryer absorbers (SDA), or in wet systems using scrubbers. Many flue gas cleaning installations have been built containing these basic components.

[5] There are several patents directed toward methods of producing small particle magnesium compounds and fuel additive compositions containing magnesium. Hunt, U.S. Patent 3,150,089 discloses a stable dispersion of a highly basic magnesium- containing inorganic compound in a non- volatile carrier, the inorganic compound being present in the form of particles having a diameter not exceeding about 0.25 micron (250 nm), which is formed by the process of (A) admixing a glycol ether solution of an oil-soluble magnesium alkoxide-carbonate complex, the complex having been prepared from a glycol ether having not more than 8 carbon atoms, an oil-soluble dispersing agent, liquid lubricating oil, and water in an amount in excess of the stoichiometric requirement for hydrolysis of the magnesium alkoxide-carbonate complex, (B) hydrolyzing the magnesium alkoxide-carbonate complex to an oil-insoluble magnesium-containing inorganic compound, and then (C) removing the volatile material.

[6] Redmore et al, U.S. Patent 4,056,479 discloses magnesium carboxylate-sulfonate complexes prepared by the process described in 3,150,089 but differs in that the 3,150,089 describes compositions prepared from either carboxylic acids or sulfonic acids, whereas Redmore describes complexes prepared from both carboxylic acids and sulfonic acids as a dual complex. In contrast to the Hunt 3,150,089 patent which prefers fatty acids which are liquids at ambient temperatures down to 15⁰C, the 4,056,479 patent of Redmore et al can employ high melting carboxylic acids such as stearic acid made possible by the combination of carboxylic acid and sulfonic acid.

[7] McCormick et al, U.S. Patent 6,503,475 discloses a process for the production of ultrafine powders that includes subjecting a mixture of precursor metal compound and a non-reactant diluent phase to mechanical milling whereby the process of mechanical activation reduces the microstructure of the mixture to the form of nano-sized grains of the metal compound uniformly dispersed in the diluent phase. The process also includes heat treating the mixture of nano-sized grains of the metal compound uniformly dispersed in the diluent phase to convert the nano-sized grains of the metal compound into a metal oxide phase. The process further includes removing the diluent phase such that the nano-sized grains of the metal oxide phase are left behind in the form of an ultrafine powder (particles in the size range of 1 nm to 200 nm, or more typically in the size range 10 nm to 100 nm).

[8] Cheng et al, U.S. Patent 4,163,728 discloses a process of preparing a stable, fluid magnesium-containing dispersion from magnesium carboxylates at low carboxylate stoichiometry, which consists essentially of decomposing a magnesium carboxylate to MgO in a non- volatile process fluid capable of being heated to the decomposition temperature of the magnesium carboxylate also containing a dispersant capable of retaining the magnesium oxide formed by the decomposition in stable suspension at a temperature greater than about 23O⁰C, the process containing less than a stoichiometric amount of carboxylate, based on Mg(OH)₂ or equivalent. The MgO particle size is preferably no greater than about 1 micron (1,000 nm). This process of requires the use of acetic acid to effect the conversion.

[9] Cheng et al, U.S. Patent 4,226,739 discloses a process of preparing a stable, fluid magnesium-containing dispersion, which consists essentially of thermally de- composing MgCO₃ to MgO in a process fluid (high boiling hydrocarbon oil) which is stable and non- volatile and capable of being heated to the decomposition temperature of the magnesium carbonate in the fluid, and which contains a dispersant (magnesium naphtenate) capable of retaining the magnesium oxide as it is formed by the thermal decomposition in stable suspension.

[10] Flanders et al, U.S. Patent 5,858,208 discloses a method for improving conversion in a fluidized catalytic cracking unit feed stream containing vanadium. According to the method, an effective amount of a composition comprising at least one overbase complex of a magnesium or aluminum salt or a mixture thereof and an organic acid complexing agent having a particle size preferably no greater than 0.1 microns (100 nm) is incorporated into the vanadium-containing feed stream as a colloidal dispersion. Disclosure of Invention Technical Problem

[11] In many prior art applications, the magnesium oxide is produced through energy intensive gaseous reactions starting from very pure sources of magnesium. Many of these materials can be difficult to produce and may carry a significant cost. Also, the resulting compounds may result in forms that are either not convenient or practical to use, or, are so expensive they have little practical value for their intended purposes.

[12] To avoid the associated high cost and unwanted contaminants, much of the magnesium oxide produced comes from other magnesium sources. These other materials have a relatively small surface area. This smaller surface area requires a greater amount of magnesium oxide be used to obtain the same effectiveness. Technical Solution

[13] The present invention is distinguished over the prior art in general, and these patents in particular by a nanoparticle size magnesium fuel additive composition formed of at least one overbase complex of a magnesium salt and an organic acid complexing agent. The additive in a semisolid particulate form or a colloidal dispersion form is mixed with coal, crude oil or heavy fuel oil prior to the combustion process in a fuel burning apparatus or injected into a boiler firebox immediately after combustion which, when combusted, synergistically generates billions of particles of magnesium oxide in situ that adsorb sulfur oxides (sulfur dioxides and sulfur trioxides) at the point when both chemical species are first formed - in the flame or just beyond it.

Advantageous Effects

[14] The fuel additive composition of the present invention is mixed with coal, crude oil or heavy fuel oil prior to the combustion process in a fuel burning apparatus or injected into a boiler firebox immediately after combustion which, when combusted, synergistically generates billions of particles of magnesium oxide in situ that adsorb sulfur oxides (sulfur dioxides and sulfur trioxides) at the point when both chemical species are first formed in the flame or just beyond it, and the in situ generated magnesium oxide particles are significantly effective in scavenging sulfur trioxide from coal fired, crude oil fired or residual heavy fuel oil fired equipment exhausts. Mode for the Invention

[15] As used herein, the term "overbased" means a metal salt having an extremely high molar ratio of transition metal to stabilizing carboxylic or sulfonic acid (for example 4:1). Overbased formulations can perform quite adequately at levels of about one-fifth of those required with "simple" oxides (such as magnesium oxide), or "neutral" or "normal" metal salt characterized by a ratio of base metal to acid of 1:1. The term "magnesium carboxylates" refers to the reaction product of a magnesium metal base and a carboxylic acid. The term "overbase complex" means an oxide or carbonate of magnesium and the magnesium salt of an organic acid "complexing agent".

[16] The present invention is directed toward a nanoparticle size fuel additive composition comprising at least one overbase complex of a magnesium salt (magnesium oxide) and an organic acid complexing agent, to form magnesium carboxylates, and is formulated to be mixed with coal, crude oil or heavy fuel oil prior to the combustion process in a fuel burning apparatus or injected into a boiler firebox immediately after combustion which, when combusted, synergistically generates billions of particles of magnesium oxide in situ that adsorb sulfur oxides in various forms from the time they are first formed.

[17] It is well known to those practiced in the art of nanotechnology that smaller particle sizes provide greatly increased surface areas. The advantage of smaller particle size is illustrated in the following table:

[18] Diameter, nm Number of Particles in 1 liter Total Surface Area M² 1000 1.9IxIO⁹ 6.OxIO³

100 1.9IxIO¹² 6.OxIO⁴

10 1.9IxIO¹⁵ 6.OxIO⁵

1 1.9IxIO¹⁸ 6.OxIO⁶

[19] As can be seen in the table above; for each order of magnitude reduction in particle size, the number of particles contained in a liter of material increases 1000 fold, while the surface area increases by a full order of magnitude. The particle size is an especially important feature for effectively combining with sulfur oxides. The typical particle sizes of the present invention are very much smaller than 200 nm (0.2 microns), and preferably have a mean particle size of about 20.7 nm (0.0207 microns). This particle size becomes even smaller as the compound is passed through the flame during combustion, as described hereinafter. [20] The following are examples of processes for forming the nanoparticle size magnesium carboxylates and are presented for purposes of illustration and not of limitation.

[21] Example 1 - Semisolid form

[22] A three-neck reaction flask is fitted with stirrer, a thermometer, and a condenser leading to a suitable water scrubber. 500 grams of water is introduced into the flask, and 1110 grams of 70% concentrated nitric acid is added slowly to the water. Then 500 grams of pure magnesium oxide is added very slowly to the acid/water solution. If the magnesium oxide does not completely dissolve, additional nitric acid is added until a clear solution results. The mixture becomes heated as the magnesium is added to the acid. After cooling, 850 grams of stearic acid and 100 grams of a paraffinic solvent or naphthenic solvent are added with stirring. The contents of the flask are exposed to UV radiation at a wavelength of between 75 and 280 mμfor a minimum of 12 hours. This has an effect on the electronic structure and behavior of the magnesium compound that prepares it for the final reaction step. The UV source is removed, and a heating mantle is fitted to the reaction flask. Heat is applied to boil the solution sufficient to remove all water, and any nitrous oxides that are formed are removed via the water scrubber. Typically, the solution is heated at 325⁰C over a three-hour period. While still warm, the contents of the flask are poured into a suitable container, and allowed to cool. After cooling, approximately 1400 grams of a light colored, semisolid magnesium compound (an overbase complex of a magnesium salt and an organic acid complexing agent, or magnesium carboxylate) is formed. This semisolid magnesium material has a very small particle size and can be used as-is, or, it can be ground using a small ball mill to obtain still smaller particles if desired. These particles break apart easily when force is applied. The choice of solvent can be any appropriate material for the intended use. Different applications may require different properties. In some applications, and aromatic solvent may be used and in other applications, a paraffinic or naphthenic solvent may be used. When a semisolid material is desired, it is important to minimize the amount of actual solvent used.

[23] Example 2 - Colloidal dispersion form

[24] Example 1 is repeated, except that after UV radiation and cooling, instead of using stearic acid and paraffinic or naphthenic solvent, 690 grams of oleic acid and 200 grams of an aromatic solvent are added with stirring. In this case after stripping water and nitrous oxide gases, about 1400 grams of a light yellow liquid product (a stable colloidal dispersion) results. This product can be used without further processing in many applications in place of standard magnesium oxide (an ionic solid MgO).

[25] In both of the above examples, the particle size of the magnesium salt (magnesium oxide or magnesium carboxylate) constituent is in the range of from about 10 nm to about 50 nm, or preferably from about 17 nm to about 27 nm, more preferably from about 20 nm to about 22 nm, and most preferably having a mean particle size of about 20.7 nm.

[26] In either form, the resulting fuel additive compositions can be mixed with coal, crude oil or heavy fuel oil prior to the combustion process in a fuel burning apparatus, such as a diesel engine or injected into a boiler firebox immediately after combustion.

[27] The magnesium salt may be formed from a magnesium precursor material selected from the group consisting of magnesium acetate dihydrate, magnesium caprylate, magnesium carbonate, magnesium hydroxide, magnesium citrate dihydrate, magnesium formate dihydrate, magnesium laurate, magnesium nitrate, magnesium oleate, magnesium oxide, magnesium oxylate, magnesium oxylate dihydrate, magnesium peroxide, magnesium stearate, and magnesium hydroxy carbonate.

[28] One of the key features of the present fuel additive compositions is that, when combusted, the nanoparticle size magnesium composition synergistically generates billions of particles of extremely reactive magnesium oxide in situ that adsorb sulfur oxides (sulfur dioxides and sulfur trioxides) at the point when both chemical species are first formed - in the flame or just beyond it, and the in situ generated magnesium oxide particles are significantly effective in scavenging sulfur trioxide from coal fired, crude oil fired or residual heavy fuel oil fired equipment exhausts. Thus, the present fuel additive compositions produces many more overall particles to contact and react or adsorb sulfur oxides in their various forms (sulfur dioxide and sulfur trioxide) in the combustion exhaust stream. The greater the chances of chemical reaction or contact, the more actual reactions or contacts will take place. By providing an incredibly large number of extremely small particles, the overall interaction of the resulting magnesium oxide with sulfur trioxide can be obtained at economically and environmentally significant levels.

[29] The resulting small particles are highly reactive and extremely well dispersed throughout the combustion gases. Because the particles are formed during actual combustion of the coal, crude oil or heavy fuel oil containing the additive, there are improved opportunities for a fresh magnesium oxide particle to make contact with a fresh sulfur trioxide molecule. Rather than having mere seconds in order to contact sulfur trioxide before reaching the electrostatic precipitators (ESP) or fabric filters (FF) - there are many minutes available for the same activity and many more collisions for a typical boiler firebox configuration to the exhaust clean-up location. The resulting larger particles are now more effectively trapped in either the ESP or the FF.

[30] The present processes for forming the nanoparticle size magnesium carboxylate can begin with either purified or unpurified magnesium compounds, which are dissolved in a mixture of mineral and/or organic acids. The magnesium salt may be formed from a magnesium precursor material selected from the group consisting of magnesium acetate dihydrate, magnesium caprylate, magnesium carbonate, magnesium hydroxide, magnesium citrate dihydrate, magnesium formate dihydrate, magnesium laurate, magnesium nitrate, magnesium oleate, magnesium oxide, magnesium oxylate, magnesium oxylate dihydrate, magnesium peroxide, magnesium stearate, and magnesium hydroxy carbonate.

[31] The UV radiation procedure, particle size separation technology, and/or thermal degradation followed by stripping of water and unwanted components produces a stable dispersion of magnesium carboxylate. Because the resulting complex of this invention is an organic soluble component, any inorganic impurities can be easily removed by simple filtration of the product before packaging.

[32] By varying the formulation composition we can produce materials as either liquids or as semisolids. This allows greater flexibility to provide more closely what is required in any marketplace or industry. This flexibility in composition is achieved by varying the ratio of transition metal (magnesium) to blended carboxylic acids. As the ratio is varied, products with vastly different properties can be manufactured. Similarly, by altering the ratio of the components of the carboxylic acid blend, materials with very different properties can be provided. For example, if solid carboxylic acids - for example, stearic acid - are selected, products that are "greasy" semisolids can be produced. Similarly, when a liquid blend of carboxylic acids - for example oleic acid - is selected, a liquid product is produced. This increases the flexibility of the final activator composition and is a unique property available to this carboxylate type chemistry.

[33] By the present invention, an appropriate carboxylic acid or acid mixture, which may be natural in origin or derived from a natural product, such as aliphatic fatty acid, or tall oil acid or a synthetic acid such as alkoxy and phenoxy fatty acids, ether and thioether monocarboxylic acids, isopentanoic acid, 2-ethylhexoic acid, isooctanoic acid, isononanoic acid or a neo acid, e.g., neodecanoic acid, is contacted with a reactant source of the desired metal, in the form of the metal powder, or an appropriate oxide, hydroxide, carbonate, or other simple salt and after appropriate reactions have been completed, undesired by products are suitably separated to obtain the desired product.

[34] Because these formulations are essentially organic compositions, they can be blended with various solvents either aromatic or paraffinic as the end user desires, based upon the properties desired. This provides the end user with even more flexibility to meet his needs.

Claims

[I] A magnesium nanoparticle size fuel additive composition for mixing with fossil fuels prior to their combustion in a fuel burning apparatus or injection into a boiler firebox immediately after combustion, comprising: at least one overbase complex of a magnesium salt and an organic acid complexing agent; said additive composition, when combusted in the fuel burning apparatus, syner- gistically generating billions of particles of magnesium oxide in situ that adsorb sulfur oxides in various forms from the time they are first formed. [2] The fuel additive composition according to claim 1, wherein said magnesium salt constituent concentration of the composition is from about 20% to about 55%. [3] The fuel additive composition according to claim 1, wherein said composition is a semisolid. [4] The fuel additive composition according to claim 1, wherein said composition is a stable, colloidal dispersion. [5] The fuel additive composition according to claim 1, wherein said magnesium salt constituent comprises particles in the size range of from about 10 nm to about 50 nm. [6] The fuel additive composition according to claim 5, wherein said magnesium salt constituent comprises particles in the size range of from about 17 nm to about 27 nm. [7] The fuel additive composition according to claim 6, wherein said magnesium salt constituent comprises particles in the size range of from about 20 nm to about 22 nm. [8] The fuel additive composition according to claim 7, wherein said magnesium salt constituent comprises particles having a mean particle size of about 20.7 nm. [9] The fuel additive composition according to claim 1, wherein said magnesium salt is an oxide or carbonate of magnesium. [10] The fuel additive composition according to claim 1, wherein said organic acid complexing agent is a carboxylic acid, sulfonate, phenate, or phosphorus acid.

[I I] The fuel additive composition according to claim 1, wherein said overbase complex comprises a complex of a magnesium salt and a magnesium salt of an organic acid complexing agent.

[12] The fuel additive composition according to claim 1, wherein said overbase complex comprises an overbase complex of magnesium oxide and a magnesium salt of an organic acid complexing agent; and an overbase complex of magnesium carbonate and a magnesium salt of an organic acid complexing agent.

[13] The fuel additive composition according to claim 1, wherein said overbase complex comprises an overbase complex of magnesium oxide and a magnesium salt of a fatty acid; and an overbase complex of magnesium carbonate and a magnesium salt of a sulfonic acid.

[14] The fuel additive composition according to claim 1, wherein said magnesium salt is formed from a magnesium precursor material selected from the group consisting of magnesium acetate dihydrate, magnesium caprylate, magnesium carbonate, magnesium hydroxide, magnesium citrate dihydrate, magnesium formate dihydrate, magnesium laurate, magnesium nitrate, magnesium oleate, magnesium oxide, magnesium oxylate, magnesium oxylate dihydrate, magnesium peroxide, magnesium stearate, and magnesium hydroxy carbonate.

[15] The fuel additive composition according to claim 1, wherein said overbase complex of magnesium salt and organic acid complexing agent has undergone UV radiation.

[16] A process for the production of a magnesium nanoparticle size fuel additive composition for mixing with fossil fuels, the process comprising: dissolving magnesium oxide in a solution of water and concentrated nitric acid, the solution becoming heated as the magnesium oxide is added; allowing the magnesium oxide/water/acid solution to cool; adding into the magnesium oxide/water/acid solution, while continuously stirring, a mixture of an acid selected from the group consisting of a stearic acid and an oleic acid and a solvent selected from the group consisting of paraffinic, naphthenic, and aromatic solvents into the magnesium oxide/water/acid solution while continuously stirring;. subjecting the magnesium oxide/water/acid/solvent solution to UV radiation; boiling the magnesium oxide/water/acid/solvent solution sufficient to remove all water, and removing any nitrous oxides that are formed such that an overbase complex of a magnesium salt and an organic acid complexing agent, or magnesium carboxylate is left behind having a nano-sized magnesium salt constituent.

[17] The process according to claim 16, comprising the further step of reducing the nano-sized magnesium salt constituent to particles in the size range of from about 20 nm to about 22 nm.

[18] The process according to claim 16, wherein said magnesium oxide/ water/acid/solvent solution is subjected to UV radiation at a wavelength of between 50 mμand 300 mμfor a minimum of 12 hours. [19] A method for scavenging sulfur oxides during the combustion process in a fossil fuel burning apparatus or a boiler firebox immediately after combustion, comprising: mixing a magnesium nanoparticle size fuel additive composition with the fossil fuel prior to its combustion in a fuel burning apparatus or injection into a boiler firebox immediately after combustion, the additive comprising at least one overbase complex of a magnesium salt and an organic acid complexing agent; wherein said additive composition, when combusted in the fuel burning apparatus, syner- gistically generates billions of particles of magnesium oxide in situ that adsorb sulfur oxides in various forms from the time they are first formed.