Classifications

• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
  • C10L1/00—Liquid carbonaceous fuels
  • C10L1/04—Liquid carbonaceous fuels essentially based on blends of hydrocarbons
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
  • C10L1/00—Liquid carbonaceous fuels
  • C10L1/10—Liquid carbonaceous fuels containing additives
  • C10L1/14—Organic compounds
  • C10L1/22—Organic compounds containing nitrogen
  • C10L1/222—Organic compounds containing nitrogen containing at least one carbon-to-nitrogen single bond
  • C10L1/2222—(cyclo)aliphatic amines; polyamines (no macromolecular substituent 30C); quaternair ammonium compounds; carbamates

Definitions

• Biodiesel fuels which constitute the short chain alkyl esters of vegetable or animal oils or fats, while having been identified in the art as useful for combustion in diesel engines or as blending stock for mixtures with conventional diesel fuels are characterized as being less stable than conventional diesel fuels.
• Biodiesel fuels are mixtures of short chain alkyl esters of saturated and unsaturated vegetable oils or animal oils or fats and as such contain olefinic double bonds as well as the ester moiety. Such functionalities are susceptible to oxidative degradation leading to the degradation of the biodiesel and its consequential unsuitability for use due to its lack of long-term stability caused by the presence therein of acids, alcohols, aldehydes, ketones, etc.
• WO 2008/056203 teaches stabilizer compositions for blends of petroleum and renewable fuels.
• Mixtures of renewable fuels such as biodiesel, ethanol and biomass mixed with conventional petroleum fuel are stabilized by the addition thereto of a multifunctional additive package which is a combination of one or more additives selected from the group consisting of a free radical chain terminating agent, a peroxide decomposition agent, an acid scavenger, a photochemical stabilizer, a gum dispersant and a metal sequestering agent.
• Peroxide decomposition agents are selected from the group containing sulfur, nitrogen and phosphorus compounds. Suitable nitrogen-containing compounds are of the general formula:
• R, R′ and R′′ can be alkyl linear, branched, saturated or unsaturated C 1 -C 30 , aromatic, cyclic, poly alkoxy, polycyclic.
• Identified as a useful nitrogen containing compound is N,N-dimethylcyclohexylamine. While N,N-dimethylcyclohexylamine is taught as a useful peroxide decomposition agent, in the examples it is never employed by itself but always in combination with a phenolic anti-oxidant.
• US2004/0152930 teaches stable blended diesel fuel comprising an olefinic diesel fuel blending stock containing olefins in an amount of 2 to 80 wt %, non-olefins in an amount of 20 to 98 wt % wherein the non-olefins are substantially comprised of paraffins, oxygenates in an amount of at least 0.012 wt % and sulfur in an amount of less than 1 ppm, the blend diesel being stabilized by an effective amount of a sulfur-free antioxidant.
• An effective amount of sulfur-free antioxidant is identified as 5 to 500 ppm, preferably 8 to 200 ppm of additive.
• the sulfur-free antioxidant is selected from the group consisting of phenols, cyclic amines and combinations thereof.
• the phenols contain one hydroxyl group and are hindered phenols.
• the cyclic amine antioxidants are amines of the formula:
• A is a six-membered cycloalkyl or aryl ring
• R 1 , R 2 , R 3 and R 4 are independently H or alkyl and X is 1 or 2.
• An example of a sulfur-free antioxidant is given as di-methylcyclohexylamine. See also U.S. Pat. No. 7,179,311.
• U.S. 2008/0127550 discloses stabilized biodiesel fuel composition wherein the stabilizing agent is a combination of: i) one or more compounds selected from the group consisting of sterically-hindered phenolic anti-oxidants; and ii) one or more compounds selected from the group consisting of triazole metal deactivators.
• U.S. 2007/0289203 discloses a stabilized biodiesel wherein the stabilizing additive is a mixture of at least one aromatic diamine and at least one sterically-hindered phenol.
• U.S. 2007/0151143 discloses a stabilized biodiesel wherein the stabilizing additive is selected from one or more of the group consisting of the 3-arylbenzofuranones and the hindered amine light stabilizers and, optionally, one or more hindered phenolic anti-oxidants.
• U.S. 2007/0248740 discloses an additive composition comprising 2,5-di-tert-butyl hydroquinone (BHQ), N,N′-disalicylidenepropylenediamine.
• BHQ 2,5-di-tert-butyl hydroquinone
• N,N′-disalicylidenepropylenediamine The additive is used to stabilize fuel containing at least 2% by weight of an oil derived from plant or animal material.
• U.S. 2007/0113467 discloses a biodiesel fuel composition having improved oxidation stability.
• the fuel contains at least one anti-oxidant that increases the oxidative stability of the fuel selected from the group recited in paragraphs [0006] to [0012] of said published application.
• U.S. Pat. No. 3,336,124 discloses stabilized distillate fuel oils and additive compositions for such fuel oils.
• One additive composition comprises a mixture of: (a) an oil soluble dispersant terpolymer of a particular type; (b) from 0.2 to about 3 parts by weight per part of said oil soluble dispersant tripolymer of N,N-dimethylcyclohexylamine; and (c) a normally liquid inert hydrocarbon carrier solvent in an amount to constitute from about 20% to 80% by weight of the additive composition. See also GB 1,036,384.
• the present invention relates to a method for improving the oxidation stability of biodiesel fuels) or mixtures or biodiesel fuel(s) and conventional diesel fuel(s) by the addition thereto of stability additive selected from the group consisting of one or a mixture of N,N-di(C 1 -C 5 -alkyl)cyclohexylamine, preferably one or a mixture of N,N-di(C 1 -C 1 -alkyl)cyclohexylamine, most preferably N,N-dimethylcyclohexylamine so as to increase the oxidation stability of said additized fuel as measured by the Rancimat Test by at least about 50%, preferably by at least about 60%, more preferably by at least about 65%, most preferably by 100% or more as compared to the oxidation stability of the fuel without the stability additive, said method comprising adding to the biodiesel fuel or mixture of biodiesel fuel and conventional diesel fuel at least 250 mg, preferably at least 500 mg, more preferably at
• the addition to such fuels of the above-described stability additive in the amounts indicated above can increase the oxidation stability time to at least the six hour minimum induction time necessary to satisfy the EN 14214 specification for stability of biodiesel fuels as measured by the Rancimat Test.
• Biodiesel fuels are mixtures of lower, short chain esters of mixed saturated and unsaturated straight chain fatty acids derived from vegetable and/or animal fats and oils.
• the straight chain fatty acids are, typically, C 10 to C 26 fatty acids, preferably C 12 to C 22 fatty acids.
• the fatty acids are made into biodiesel by transesterification using short chain alcohols; e.g., C 1 to C 5 alcohols, in the presence of a catalyst such as a strong base.
• Vegetable and/or animal oils and fats are natural triglycerides and are renewable sources of starting material.
• Typical vegetable oils are soybean oil, rapeseed oil, corn oil, jojoba oil, safflower oil, sunflower seed oil, hemp oil, coconut oil, cottonseed oil, sunflower oil, palm oil, canola oil, peanut oil, mustard seed oil, olive oil, spent cooking oil, etc., without limitation.
• Animal fats and oils include beef, pork, chicken fat, fish oil and oil recovered by the rendering of animal tissue.
• the biodiesel is made by esterifying one or a mixture of such oils and fats using one or a mixture of short chain; e.g., C 1 to C 5 , alcohols, preferably methanol.
• Transesterification is effected by the base catalyzed reaction of the fat and/or oil with the alcohol, direct acid catalyzed esterification of the oil and/or fat with the alcohol, conversion of the oil and/or fat to fatty acids and then to alkyl esters with as acid catalyst.
• base catalyzed transesterification the oil and/or fat is reacted with a short chain (such as methanol or ethanol) alcohol in the presence of a catalyst such as sodium hydroxide or potassium hydroxide to produce glycerin and short chain alkyl esters.
• the glycerin is separated from the product mixture and biodiesel is recovered. Any unreacted alcohol is removed by distillation. The recovered biodiesel is washed to remove residual catalyst or soap and dried.
• the fuel is either 100% biodiesel, typically identified in the art as B 100, or it is a mixture of biodiesel with conventional diesel fuel; i.e., X % conventional diesel fuel and Y % biodiesel which would be identified as BY; for example, 80% conventional diesel and 20% biodiesel fuel would be described as B20.
• the biodiesel fuel has its stability against oxidation increased by at least 50%, preferably by at least 60%, more preferably by at least 65%, most preferably by 100% or more, as measured by the Rancimat Test by the addition thereto of the above-described stability additive in the amount indicated.
• Biodiesel fuels or mixtures of biodiesel fuel and conventional fuels exhibiting oxidation stabilities of less than six hours can have their oxidation stabilities increased to an extent sufficient to meet the six hour induction time specification established in EN 14214 for biodiesel fuels as measured by the Rancimat Test (ISO 6886).
• the biodiesel can be combined with N,N-dimethylcyclohexylamine (DMCHA) in an amount of at least 250 mg, preferably at least 500 mg, more preferably at least 1000 mg of DMCHA per liter of biodiesel fuel (B100) or per liter of the biodiesel fuel component in the mixture of biodiesel fuel and conventional diesel fuel.
• DMCHA N,N-dimethylcyclohexylamine
• the determination whether the fuel when additized has its oxidation stability increased by at least 50%, preferably by at least 60%, more preferably by at least 65%, most preferably by 100% or more as compared to the fuel without the additive, or, alternatively, meets the minimum six hours induction time is made by subjecting the fuel to the Rancimat Test (ISO 6886, per EN 14112).
• Rancimat Test samples of liquid are aged at a constant temperature (110° C.) while air is passed through the liquid at a rate of 10 liters/hour.
• the exhaust airflow passes through a measuring cell filled with distilled water. The conductivity of the measuring cell is determined continuously and recorded automatically.
• the biodiesel fuels can contain other performance additives commonly used in conventional diesel fuels such as dispersants, detergents, cetane improvers (such as 2-ethyl hexyl nitrate), demulsifiers, biocides, antifoaming agents, lubricity additives, dyes.
• performance additives commonly used in conventional diesel fuels such as dispersants, detergents, cetane improvers (such as 2-ethyl hexyl nitrate), demulsifiers, biocides, antifoaming agents, lubricity additives, dyes.
• supplemental anti-oxidant e.g., phenolic and/or aromatic amine
• supplemental phenol preferably hindered phenol and/or amine, preferably aromatic amine (e.g., diphenyl amines or phenylnaphthyl amines) anti-oxidant not be employed in the stabilization process of the present invention.
• the Rancimat oxidation tests were run according to EN 14112.
• B100 canola methyl ester an unsaturated fatty acid methyl ester
• the N,N-dimethylcyclohexylamine was acquired from Innospec.
• Dicyclocarbodiimide acid scavenger Additin RC 8500 was acquired from Akzo Nobel.
• the 2-ethylhexyl-3,4-epoxycyclohexane carboxylate acid scavenger was acquired from ATOFINA.

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• Chemical & Material Sciences (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Liquid Carbonaceous Fuels (AREA)

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Citations (12)

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• 2009
  • 2009-09-17 EP EP09814893.5A patent/EP2342311B1/en not_active Not-in-force
  • 2009-09-17 WO PCT/US2009/005185 patent/WO2010033201A1/en active Application Filing
  • 2009-09-17 JP JP2011526874A patent/JP2012503040A/ja active Pending
  • 2009-09-17 US US13/061,761 patent/US20110146139A1/en not_active Abandoned
  • 2009-09-17 CA CA2734958A patent/CA2734958A1/en not_active Abandoned
  • 2009-09-17 AU AU2009292637A patent/AU2009292637A1/en not_active Abandoned

Patent Citations (13)

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