Method for reducing flammable creosote and other organic deposits in fireboxes

Abstract

A composition and method for creosote control in firebox flues burning solid fuels combines hydrophobic metal additives with a fire accelerant. According to certain embodiments, the compositions may inhibit corrosion of metal flues in addition to creosote deposits. When the metal salts are added to an accelerant at effective concentrations, the combination delivers the metal catalyst to the lining of the exhaust system upon combustion. As such, the metals are conveniently and efficiently transported up the flue.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This document is a U.S. Utility patent application Ser. No. which is related to, and claims the priority through earlier filed U.S. Provisional Patent Application Ser. No. 60/993,850, filed on Sep. 13, 2007, all the subject matter of which is herein incorporated by this reference thereto in its entirety for all purposes.

BACKGROUND

1. Field of the Invention

The present invention relates to a composition and method for reducing flammable 10 creosote and other organic deposits in fireboxes.

2. Description of the Related Art

The maintenance of solid fuel-burning exhaust systems is important to avoid chimney fires that can destroy property. In wood and other solid fuel burning stoves, creosote builds up on the walls of the chimney or flue, and can reach dangerous levels if not cleaned on a regular basis. Various transition metals have been shown to catalyze the breakdown of creosote and inhibit the flammability of the material. Most of these metals form inorganic salts that are soluble in aqueous solutions, but not in common fire accelerants. Though these metals may be effective in reducing creosote, they are difficult to transport up the flue, necessitating methods such as spraying an aqueous solution containing metals up the flue prior to use.

U.S. Pat. Nos. 2,141,848 and 3,007,781 disclose soot removers which are soluble in oil for controlling soot in oil burning furnaces, but do not deal with solid fuel which produces deposits fundamentally different from oil.

SUMMARY

The present invention relates to hydrophobic metal additives for combination with a fire accelerant and their use in the ignition of solid fuels and preventing, removing, and/or inhibiting creosote deposits resulting from the burning of solid fuels. Additionally, according to certain embodiments, the compositions may inhibit corrosion of metal flues in addition to creosote deposits. When the metal salts are added to an accelerant at effective concentrations, the combination delivers the metal catalyst to the lining of the exhaust system upon combustion to effectively breakdown creosote residue and inhibit the buildup of new creosote deposits. The metal salts are homogenously dispersed in the accelerant, and do not need to be agitated prior to use. As such, the metals are conveniently and efficiently transported up the flue.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The detailed description set forth below is intended as a description of exemplary embodiments and is not intended to represent the only forms in which the exemplary embodiments may be constructed and/or utilized. The description sets forth the functions and the sequence of steps for constructing and/or operating the exemplary embodiments. However, it is to be understood that the same or equivalent functions and sequences may be accomplished by different exemplary methods are also intended to be encompassed within the spirit and scope of the invention, and within the scope and judgment of the skilled person.

The present invention provides hydrophobic metal salts which can be combined with a fire accelerant for preventing, inhibiting and/or removing creosote deposits resulting from the burning of solid fuels. The present invention combines a metal component which provides creosote control, with organic counterions, such as sulfates, nitrates, acetates, etc. which confer hydrocarbon solubility upon the metal catalyst. Additionally, a subset of these counterions themselves can act as corrosion inhibitors of ferrous and non-ferrous metal exhaust systems. Therefore, according to certain embodiments, the composition may contain a metal salt which has a dual role of creosote and corrosion control. According to an alternate embodiment, the composition combines creosote inhibiting salts with corrosion inhibiting salts.

When an effective amount of metal salts of the present invention are added to an accelerant, the combination delivers the metal catalyst to the lining of the exhaust system upon combustion. The metal catalysts effectively breakdown creosote residue and inhibits the buildup of new creosote deposits, and can also act to inhibit corrosion of metal flues.

The creosote and/or corrosion control additive composition of the present invention comprises a hydrocarbon soluble transition metal salt, having a chemical structure of the formula:

X^+m[Y⁻ⁿ]_p,

• • wherein X is a transition metal having an ionic charge of +m,
  • Y is an aliphatic anion, having a charge of −n, and
  • m=pn.

Preferred transition metals include Mn, Zn, Ti, V, Cr, Fe Co, Ni, and Cu; with Mn being the most preferred. Other possible transition metals include, but are not limited to Zr, Mo, Ru, Rh, Pd, Ta, W, Re, Ir, Pt, Au and Pb. Other transition metals may also be possible, as will be understood by one skilled in the art, but the above mentioned are believed to be the most ideal.

Preferred anions include carboxylate (RCOO⁻) or sulfonate (RSO₃⁻) hydrocarbons. Other possible anionic groups include, but are not limited to phosphonates (RPO₃^{−H or RPO}₃²⁻), sulfinates (RSO₂⁻), sulfenate (RSO⁻), alkoxides (RO⁻), sulfides (RS⁻), amides (of the type RN⁻R′), amides (of the type RCON⁻R₁), and acetoacetates (RCOC⁻O₂R²). Other anions may also be possible, as will be understood by one skilled in the art, but the above mentioned are believed to be the most ideal.

Additionally, R and R′ can each be a hydrocarbon group which may include H, aliphatic alkyl, alkenyl, alkynyl, and hydrocarbon chains containing halogens, nitrogen, oxygen, phosphorus, sulfur, etc., aromatics and cycles (including heterocycles, carbocycles, etc.) as well as ambiphilic chains (heteroatom containing chains) of suitable organic solubility.

Creosote control is primarily addressed through the metal component, while the hydrocarbon solubility is provided by the aliphatic anion. Additionally, certain organic anions can also function as corrosion inhibitors. For a list of organic anions known to be efficient corrosion inhibitors for a wide variety of metals see “Corrosion Inhibitors—An Industrial Guide” 2nd Edition; Flick, Ernest W. ©01993 William Andrew Publishing/Noyes). Calcium dinonylnaphthalene sulfonate is one example of an oil-soluble organic counterion suitable for both ferrous and non-ferrous applications. The mechanism of inhibition for any single corrosion inhibitor is almost certainly a complex set of multiple pathways resulting in the macroscopic effect of corrosion inhibition. It is believed that organic sulfates, acetates and nitrates, form a passivation layer which inhibits the oxidation or reduction portion of the redox corrosion system (system dependent) and buffers the pH of the system thereby preventing proton reduction. The organic solubilizing characteristics of the counterion also allow diffusion into the organic creosote deposits providing access to the underlying metal exhaust system.

The metal salts may be effective when added to the accelerant at a concentration of to above approximately 0.01% (w/v). Preferably, the salts are added to the accelerant at concentration of between approximately 0.1-25% (w/v) and more preferably at approximately 1-5% (w/v).

The fire accelerant, which can include any commercially available accelerant, is preferably composed of saturated hydrocarbons that may be a mixture of branched, straight chain or saturated cyclic structures whose flash point is around 74° C. (165° F.). For typical application in solid fuel fire starting, approximately 1-5 ounces of the composition of the invention is applied to the solid fuel prior to ignition.

A first embodiment of the invention is a hydrocarbon-soluble creosote inhibitor composition, comprising a hydrocarbon-soluble manganese salt being diluted with a mixture of saturated hydrocarbons to form an additive mixture having flammability characteristics for ignition of solid fuels in which said composition includes about:

Manganese naphthenate (Wako)     2% (w/v)
Or
Manganese 2-ethylhexanoate
Saturated hydrocarbons (Drakesol 165, Penreco) Balance

A second embodiment of the invention is a hydrocarbon-soluble creosote and corrosion inhibitor composition, comprising a hydrocarbon-soluble manganese dinonylnaphthalene sulfonate salt being diluted with a mixture of saturated hydrocarbons to form an additive mixture having the flammability characteristics for ignition of solid fuels in which said composition includes about:

Manganese dinonylnaphthalene sulfonate 5% (w/v)
Saturated hydrocarbons (Drakesol 165, Penreco) Balance

To prepare Manganese dinonylnaphthalene sulfonate, dinonylnaphthalene could first be prepared by aluminum chloride-catalyzed alkylation at 60° C. using fractionally distilled 1-α-nonenes derived from trimerization of propylene. A heart cut of the dinonylnaphthalene fraction could then be sulfonated with Sulfan B at −8° C. and titrated to neutralization with sodium hydroxide. Isopropyl alcohol extraction is then used to separate NaDNNS from the unsulfonated oil, and the manganese salt is prepared by contacting with concentrated MnCl₂ solutions. (see “The Micelle Phase of Calcium Dinonylnaphthalene Sulfonate in n-Decane,” Frederick M. Fowkes J. Phys. Chem.; 1962; 66(10); 1843-1845). Other methods for the preparation of Manganese dinonylnaphthalene sulfonate may be known to one skilled in the art.

A third embodiment of the invention is a hydrocarbon-soluble creosote and corrosion inhibitor composition, comprising a creosote inhibiting hydrocarbon-soluble Manganese 2-ethylhexanoate salt and a corrosion inhibiting sulfonate salt being diluted with a mixture of saturated hydrocarbons to form an additive mixture having flammability characteristics for ignition of solid fuels in which said composition includes about:

Manganese 2-ethylhexanoate       2% (w/v)
Calcium dinonylnaphthalene sulfonate (Na-Sul ™ 1-3% (w/v)
CA-HT3, King Industries, Inc.)
Saturated hydrocarbons (Drakesol 165 ™, Balance
Penreco)

In preparing the above compositions, the metal salts are mixed into the accelerant until homogenously dispersed. Once evenly dispersed, the compositions need not be agitated prior to use.

The inventive composition was field tested using wood-burning devices containing steel flues with no adverse effects in performance. Identical wood-burning stoves were constructed and fitted with identical steel stove-pipe flues. The stoves were fueled with equal quantities of wood continuously over a period of at least twelve days. The first “control” stove was treated with 1-2 ounces of Drakesol 165™ every 24 hour period. The second competing stove was treated with 1-2 ounces of Drakesol 165™ containing manganese 2-ethylhexanoate (1% w/v) every 24 hours. After a twelve day period, the stove pipe sections were removed and analyzed. The manganese treated stove pipe was 20% lighter than the control stove pipe, and contained <50% the creosote. Additionally, the creosote present on the control stove pipe was instantly ignited (thereby causing a controlled chimney fire) using a butane/air flame (˜1200° C.), while the manganese treated creosote was incapable of ignition even after long exposure (60 seconds) to the same flame source. Although the formulation proved efficacious down to 0.1% w/v manganese, lower concentrations should also be viable.

The system and compositions of the present invention may be used with any common solid fuel burning systems including, but not limited to, wood, charcoal, peat, coal, and pellets made from wood, corn, wheat, rye and other grains. Furthermore, the invention can be useful for treating creosote deposits in any kind of flue including masonry and metal. The composition can further be used to periodically clean or reduce combustibility of a flue system where solid fuel is regularly burned.

In closing, it is to be understood that the exemplary embodiments described herein are illustrative of the principles of the present invention. Other modifications that may be employed are within the scope of the invention. Thus, by way of example, but not of limitation, alternative configurations may be utilized in accordance with the teachings herein. Accordingly, the description is illustrative and not meant to be a limitation thereof.

Claims

1. A composition for use in solid fuel burning flues, comprising:

(a) a hydrocarbon based fire accelerant; and

(b) a hydrocarbon soluble transition metal salt added to said accelerant, said metal salt having a chemical structure of the formula: X+m[Y−n]p, wherein (i) X is a transition metal having an ionic charge of +m and selected from the group comprising Mn, Zn, Ti, V, Cr, Fe Co, Ni, and Cu; (ii) Y is an aliphatic anion, having a charge of −n, and selected from the group comprising RCOO−, RSO3−, RPO3−H, RPO32−, RSO2−, RSO−, RO−, RS−, RN−R′, RCON−R1, and RCOC−O2R2, wherein R and R′ are each a hydrocarbon group selected from H, aliphatic alkyl, alkenyl, alkynyl, and hydrocarbon chains containing halogens, nitrogen, oxygen, phosphorus, and sulfur, aromatics, cycles, and ambiphilic chains; and (iii) m=pn, and wherein said composition is effective in controlling creosote deposits resulting from the burning of said solid fuels in a firebox flue.

2. The composition of claim 1 wherein said hydrocarbon transition metal salt comprises manganese naphthenate, manganese 2-ethylhexanoate, manganese dinonylnaphthalene sulfonate, or combinations thereof.

3. The composition of claim 2 wherein said composition further includes calcium dinonylnaphthalene sulfonate.

4. The composition of claim 1 wherein said composition is effective in controlling corrosion of metal flues.

5. The composition of claim 1 wherein said composition is effective in inhibiting combustibility of said flues.

6. The composition of claim 1 wherein said transition metal salt is added to said accelerant at a concentration of between approximately 0.01% and 25% (w/v).

7. The method of claim 1, wherein said transition metal salt remains homogenously dispersed in said accelerant after initial mixing.

8. A method of maintaining a flue system burning solid-fuel, said flue system including an exhaust, the method comprising:

(a) providing an accelerant comprising saturated hydrocarbons with added metal salts, said metal salts being soluble in said saturated hydrocarbons and having a chemical structure of the formula: X+m[Y−n]p, wherein (i) X is a transition metal having an ionic charge of +m and selected from the group comprising Mn, Zn, Ti, V, Cr, Fe Co, Ni, and Cu; (ii) Y is an aliphatic anion, having a charge of −n, and selected from the group comprising RCOO−, RSO3−, RPO3−H, RPO32−, RSO2−, RSO−, RO−, RS−, RN−R′, RCON−R1, and RCOC−O2R2, wherein R and R′ are each a hydrocarbon group selected from H, aliphatic alkyl, alkenyl, alkynyl, and hydrocarbon chains containing halogens, nitrogen, oxygen, phosphorus, and sulfur, aromatics, cycles, and ambiphilic chains; and (iii) m=pn; and

(b) igniting said accelerant, wherein said metal salts are delivered to said exhaust upon igniting.

9. The method of claim 8, wherein said accelerant is applied to a solid fuel which is ignited with the accelerant.

10. The method of claim 8, said flue system being at least partially metal, wherein said metal salts are effective in controlling corrosion of the metal.

11. The method of claim 8, wherein said metal salts are effective in preventing combustibility of said flue system including said exhaust.

12. The method of claim 8, wherein said metal salts are effective in controlling creosote deposits in said flue system including said exhaust.

13. The method of claim 12, said accelerant further comprising calcium dinonylnaphthalene sulfonate.

14. The method of claim 8, said accelerant comprising:

manganese naphthenate, manganese 2-ethylhexanoate, manganese dinonylnaphthalene sulfonate, or combinations thereof, and

optionally, calcium dinonylnaphthalene sulfonate.

15. The method of claim 8, said solid fuel being wood, charcoal, peat, coal, corn, grains, or combinations thereof.

16. The method of claim 8, said metal salt being present at a concentration of between approximately 0.01% and 25% (w/v) of said accelerant.

17. The method of claim 8, said method comprising periodically igniting said accelerant in said flue system in order to clean said flue system.

18. A method of inhibiting corrosion, flammability, and/or creosote deposit in a flue system in which solid fuel is burned, said method comprising:

a) providing a hydrocarbon soluble transition metal salt having a chemical structure of the formula: X+m[Y−n]p, wherein (i) X is a transition metal having an ionic charge of +m and selected from the group comprising Mn, Zn, Ti, V, Cr, Fe Co, Ni, and Cu; (ii) Y is an aliphatic anion, having a charge of −n, and selected from the group comprising RCOO−, RSO3−, RPO3−H, RPO32−, RSO2−, RSO−, RO−, RS−, RN−R′, RCON−R1, and RCOC−O2R2, wherein R and R′ are each a hydrocarbon group selected from H, aliphatic alkyl, alkenyl, alkynyl, and hydrocarbon chains containing halogens, nitrogen, oxygen, phosphorus, and sulfur, aromatics, cycles, and ambiphilic chains; and (iii) m=pn; and

b) delivering said salt to components of the flue system during ignition of a fuel in the system.

19. The method of claim 18, comprising delivering to the flue system manganese naphthenate, manganese 2-ethylhexanoate, manganese dinonylnaphthalene sulfonate, or combinations thereof; and optionally calcium dinonylnaphthalene sulfonate.