Patent Application
20050268535
1. Field of the Invention
This invention relates to a biodiesel fuel additive composition for bulk addition to diesel fuel. More particularly, this invention relates to a biodiesel fuel additive composition comprising a fuel conditioner component comprising (i) a polar oxygenated hydrocarbon compound, and (ii) an oxygenated compatibilizing agent for use in bulk production of biodiesel fuels for improving performance, increasing Cetane number, and reducing emissions from diesel engines.
Furthermore, this invention relates to a biodiesel fuel additive composition comprising: (a) a detergent component selected from the group consisting of (i) a reaction product component of a substituted hydrocarbon and an amino compound, and (ii) a polybutylamine or polyisobutylamine; and (b) a fuel conditioner component comprising (i) a polar oxygenated hydrocarbon compound, and (ii) an oxygenated compatibilizing agent for use in bulk production of biodiesel fuels for improving performance.
2. Description of the Related Art
Biodiesel is the name for a variety of ester-based oxygenated fuels made from vegetable oils, animal fats, used cooking oil, and waste from pulp and paper industry. It is produced by the reaction between vegetable oil or animal fat and alcohol in the presence of a catalyst. The concept of using vegetable oil as a fuel dates back to 1895 when Dr. Rudolf Diesel developed the first diesel engine to run on vegetable oil. Diesel demonstrated his engine at the World Exhibition in Paris in 1900 using peanut oil as fuel.
Today's diesel engines require a clean-burning, stable fuel that performs well under a variety of operating conditions. Biodiesel is the only alternative fuel that can be used directly in any existing, unmodified diesel engine. Since biodiesel is produced from renewable domestically grown feedstock, it can reduce the use of petroleum-based diesel fuel and possibly lower the overall greenhouse gas emissions from the use of internal combustion engines. Biodiesel, due to its biodegradable nature, is especially attractive for marine application in environmentally sensitive areas. With essentially no sulfur and aromatic contents, biodiesel offers promise to reduce particulate and toxic emissions.
Compared to conventional diesel, biodiesel is chemically simple since it contains only six or seven fatty acid esters. However, different esters vary in terms of important fuel properties, such as Cetane Number (CN), viscosity, Cloud and Pour points, and degree of saturation. The presence of impurities also affects the fuel properties. Therefore, fuel related biodiesel properties are generally affected by the nature of the feedstock.
Generally speaking, biodiesel fuels have higher CN, higher viscosity, and higher Cloud and Pour points compared to conventional diesel fuels. Biodiesel blends with diesel fuel show a near linear relationship for most of the fuel properties. Hence the properties of B20 (20% biodiesel: 80% diesel) are a lot closer to diesel fuel properties than those of neat (100% biodiesel). The B20 is the most popular blend of biodiesel in diesel fuel. It has been recognized as an alternative fuel under the Energy Policy Act (EPACT) in the United States.
Besides the overall positive effect of biodiesel on emissions, there are many other issues that are relevant to the use of biodiesel in diesel engines since they influence engine performance and durability. Some of the important issues are proper mixing of biodiesel in diesel fuel, loss of engine power, cold start problems, material compatibility, engine wear, and the effect on engine lubricating oil.
Biodiesel on a volumetric basis contains slightly less energy than conventional diesel fuel. Hence using biodiesel without any change in the fuel injection system could result in a slight loss of engine power. It has been reported that fuel filter plugging, the gum like accumulation in injection pumps, and injector cavitation may be responsible for power loss. All of these problems are attributable to biodiesel fuel quality issues.
Biodiesel has higher Cloud and Pour point temperatures than diesel fuel, which can create starting problems in cold weather. Biodiesel may not be compatible with certain materials that could lead to premature failure of some components such as fuel pumps, fuel lines, and valves. Based on the wear-metal analysis of engine lubricating oil, the engine wear and lubricating oil dilution were generally within the specified range while using B20 fuel. The Engine Manufacturers Association (EMA), however, recommends that when using biodiesel, the normal oil change interval should be cut by half.
It is an object of this invention to provide a biodiesel fuel additive for alkyl biodiesel fuels, which accelerates the combustion phenomenon and reduces ignition delay in diesel engines. It is a feature of this invention that the additive comprises a detergent component and a fuel conditioner component, which synergistically interact to reduce particulate emissions and increase Cetane number.
It is a further object of this invention that the additive comprises a fuel conditioner component, which synergistically interacts with biodiesel to reduce particulate emissions and increase Cetane number.
It is an advantage of this invention that it also reduces fuel consumption in diesel engines.
A biodiesel fuel additive composition which accelerates the combustion phenomenon, reduces ignition delay and increases Cetane number while retaining engine performance comprising a mixture of: a fuel conditioner component comprising: (i) from about 10 to about 70 weight percent, based upon the total weight of the additive, of a polar oxygenated hydrocarbon having an average molecular weight in the range of about 200 to about 500, an acid number in the range of about 25 to about 175, and a saponification number in the range of about 30 to about 250, and (ii) from about 10 to about 70 weight percent, based upon the total of the additive, of an oxygenated compatibilizing agent preferably having a solubility parameter in the range of about 7.0 to about 14.0 and moderate to strong hydrogen capacity.
Another object of the present invention is directed to a biodiesel fuel additive composition that reduces particulate emissions and improves fuel economy while improving engine performance comprising a mixture of: (a) from about 10 to about 90 weight percent, based upon the total weight of the additive, of a detergent component selected from the group consisting of (i) a reaction product of: (A) a substituted hydrocarbon of the formula
R1-X (I)
wherein R1 is a hydrocarbyl radical having a molecular weight in the range of about 150 to about 10,000, and X is selected from the group consisting of halogens, succinic anhydride and succinic dibasic acid, and (B) an amino compound of the formula
H—(NH-(A)m)n-Y-R2 (II)
wherein Y is O or NR5′R5 being H or a hydrocarbyl radical having 1-30 carbon atoms; A is a straight chain or branched chain alkylene radical having 1-30 carbon atoms; m has a value in the range of 1-15; n has a value in the range of 0-6; and R2 is selected from the group consisting of H, a hydrocarbyl radical having a molecular weight in the range of about 15 to about 10,000, and a homopolymeric or heteropolymeric polyoxyalkylene radical of the formula
R3-((Q)a(T)b(Z)c)d- (III)
wherein R3 is H or a hydrocarbyl radical having 1-30 carbon atoms, Q, T, and Z are polyoxyalkylene moieties having 1-6 carbon atoms, a, b and c each have values ranging from 0-30, and d has a value in the range of 1-50, and (ii) a polybutylamine or polyisobutylamine of the formula
where R11 is a polybutyl or polyisobutyl radical derived from isobutene and up to 20% by weight of n-butene and R12 and R13 are identical or different and are each hydrogen, an aliphatic or aromatic hydrocarbon, a primary or secondary, aromatic or aliphatic aminoalkylene radical or polyaminoalkylene radical, a polyoxyalkylene radical or a heteroaryl or heterocyclyl radical, or, together with the nitrogen atom to which they are bonded, form a ring in which further hetero atoms may be present; and (b) a fuel conditioner component comprising: (i) from about 10 to about 70 weight percent, based upon the total weight of the additive, of a polar oxygenated hydrocarbon having an average molecular weight in the range of about 200 to about 500, an acid number in the range of about 25 to about 175, and a saponification number in the range of about 30 to about 250, and (ii) from about 10 to about 70 weight percent, based upon the total of the additive, of an oxygenated compatibilizing agent preferably having a solubility parameter in the range of about 7.0 to about 14.0 and moderate to strong hydrogen capacity.
In one preferred embodiment of the present invention the amino compound of the formula
H—(NH-(A)m)n—Y—R2 (II)
(i) would be made from I and II, II preferably comprising Y═NR5 and R5=U H where U is a polysubstituted, linear or branched, moiety with 1 to 10 carbon units and the resulting compound V further comprises at least one linear or branched carboxylic monoacid or anhydride compound. The compounds I, II and V are necessarily reacted in proportion other than 1:1:1 as described in the U.S. Pat. No. 6,083,287.
The fuel conditioner component may additionally comprise a hydrophilic separant such as a glycol monoether. The additive composition may additionally comprise a carrier oil or fluidizer.
This invention is also directed to a biodiesel fuel containing the present invention which may be added with any other additives or added after the addition of any other additives.
This invention is in one aspect directed to a biodiesel fuel additive comprising: (a) a detergent component which is selected from the group consisting of (i) the reaction product of a substituted hydrocarbon and an amino compound, (ii) a polybutylamine or polyisobutylamine; and (b) a fuel conditioner component comprising a polar oxygenated hydrocarbon compound and an oxygenated compatibilizing agent.
Another aspect of the present invention is directed to a biodiesel fuel additive comprising (a) a fuel conditioner component comprising a polar oxygenated hydrocarbon compound and an oxygenated compatibilizing agent.
If the reaction product detergent component is employed, the substituted hydrocarbon reactant used to prepare the reaction product is of the formula
R1-x (I)
wherein R1 is a hydrocarbyl radical having a molecular weight in the range of about 150 to about 10,000, preferably a polyalkylene radical having a molecular weight in the range of about 400 to about 5000, most preferably a polyalkylene radical having a molecular weight in the range of about 600 to about 1500, and X is selected from the group consisting of halogens, preferably chlorine, succinic anhydride and succinic dibasic acid. in one preferred embodiment, R1-X is a polyisobutenyl succinic anhydride. In another preferred embodiment, R1-X is a chloropolyisobutylene, The amino compound reactant used to prepare the reaction product is of the formula
H—(NH-(A)m)n-Y-R2 (II)
wherein Y is O or NR5′, R5 being H or a hydrocarbyl radical having 1-30 carbon atoms, preferably 1-22 carbon atoms; A is a straight chain or branched chain alkylene radical having 1-30, preferably 1-15 carbon atoms; m has a value in the range of 1-15, preferably 1-12; n has a value in the range of 0-6, preferably 0-5; and R2 is selected from the group consisting of H, a hydrocarbyl radical having a molecular weight in the range of about 15 to about 10,000, preferably 15 to about 2000, and a homopolymeric or heteropolymeric polyoxyalkylene radical of the formula
R3-((Q)a(T)b(Z)c)d- (III)
wherein R3 is H or a hydrocarbyl radical having 1-30, preferably 1-22 carbon atoms, Q, T, and Z are polyoxyalkylene moieties having 1-6 carbon atoms, a, b, and c each have values ranging from 0-30, and d has a value in the range of 1-50, preferably 1-25.
Various preferred embodiments of the amino compound reactant of formula (II) are given in Table 1 below:
In another preferred embodiment, R2 is the above-described homopolymeric or heteropolymeric polyoxyalkylene radical of formula (III). As used in this description and in the appended claims, the terms homopolymeric and heteropolymeric refer to polyoxyalkylene compounds, which in the case of homopolymeric compounds contain one recurring polyoxyalkylene moiety, and in the case of heteropolymeric compounds contain more than one recurring polyoxyalkylene moiety, typically having 1-6 carbon atoms, such as ethylene oxide (EO), propylene oxide (PO) or butylene oxide (BO). Thus, for example, in one embodiment R2 may be a homopolymeric polyoxyalkylene radical of the formula
R3-((EO))d-
wherein in formula (III), a=I, b=0, c=0, Q=ethylene oxide, and R3 and d are as previously defined. In another embodiment, R2 may be a heteropolymeric polyoxyalkylene radical of the formula
R3-((EO)a(PO)b(BO)c)d-
wherein, in formula II, Q=ethylene oxide, T=propylene oxide, Z=butylene oxide, and a, b, c, d and R3 are as previously described.
In yet another preferred embodiment, the above-described amino compound reactant is selected from the group consisting of polyethylene polyamines, polypropylene polyamines and mixtures thereof. In yet another preferred embodiment, such polyamines are monoalkylated.
The reaction product component is preferably prepared by reacting the substituted hydrocarbon R1-X to the amino compound in a mole ratio in the range of 0.2:1-20:1, more preferably in the range of 0.5:1-10:1. The reaction product component may be prepared under reaction conditions (including e.g. reaction times, temperatures, and reagent proportions) as are well known by those skilled in the art for preparing such amino compound-substituted hydrocarbon reaction products. The method for preparing such reaction products is described, for example, in U.S. Pat. No. 3,172,892 (LeSeur et al.), U.S. Pat. No. 3,438,757 (Honnen et al.), and U.S. Pat. No. 3,443,918 (Kautsky et al.), all of which are incorporated herein by reference.
In a specific embodiment V is selected from the group methacrylic acid, acrylic acid, malaic anhydride . . . as described in U.S. Pat. No. 6,083,287.
The detergent compound may also be a polybutylamine or polyisobutylamine of the formula (IV)
where R11 is a polybutyl- or polyisobutyl radical derived from isobutene and up to 20% by weight of n-butene, and R12 and R13 are identical or different and are each hydrogen, an aliphatic or aromatic hydrocarbon, a primary or secondary, aromatic or aliphatic aminoalkylene radical or polyaminoalkylene radical, a polyoxyalkylene radical or a heteroaryl or heterocyclyl radical, or, together with the nitrogen atom to which they are bonded, form a ring in which further hetero atoms may be present.
Compounds of the general formula (IV) and the method of preparation thereof are disclosed, for example, in U.S. Pat. No. 4,832,702 (Kummer et al.), incorporated herein by reference. Compounds of the general formula (IV) are preferably prepared in accordance with the method disclosed in U.S. Pat. No. 4,832,702, wherein an appropriate polybutene or polyisobutene is hydroformylated with a rhodium or cobalt catalyst in the presence of CO and H2 at from about 80-200° C. and CO/H2 pressures of up to 600 bar, and the oxo product thereby formed is then subjected to a Mannich reaction or amination under hydrogenating conditions, wherein the amination reaction is advantageously carried out at 80-200° C. and under pressures up to 600 bar, preferably 80-300 bar.
The fuel conditioner component employed in admixture with the detergent component to produce the additive of this invention may preferably be the fuel conditioner previously disclosed in U.S. Pat. No. 4,753,661 (Nelson et al.), incorporated herein by reference. This fuel conditioner comprises a polar oxygenated hydrocarbon compound and an oxygenated compatibilizing agent.
The polar oxygenated hydrocarbon portion of the fuel conditioner signifies various organic mixtures arising from the controlled oxidation of petroleum liquids with air. Often these air oxidations of liquid distillates are carried out at a temperature of from about 100° C. to about 150° C. with an organo-metallic catalyst, such as esters of manganese, copper, iron, cobalt, nickel or tin, or organic catalysts, such as tertiary butyl peroxide. The result is a melange of polar oxygenated compounds which may be divided into at least three categories: volatile, saponifiable and non-saponifiable.
The polar oxygenated compounds preferable for use in the present invention may be characterized in a least three ways, by molecular weight, acid number, and saponification number. It is to be appreciated by those skilled in the art that the terms “molecular weight” and “average molecular weight” are synonymous and are herein used interchangeably. It is to be further appreciated that there are several methods of determining the average molecular weight of an organic material and that different methods will produce different results for the same material. Chemically these oxidation products are mixtures of acids, hydroxy acids, lactones, eaters, ketones, alcohols, anhydrides, and other oxygenated organic compounds. Those suitable for the present invention are compounds and mixtures with an average molecular weight between about 200 and about 500, with an acid number between about 25 and about 175 (ASTM-D-974), and a saponification number from about 30 to about 250 (ASTM-D-974-52). Preferably the polar oxygenated compounds of the present invention have an acid number from about 50 to about 100 and a saponification number from about 75 to about 200.
Suitable compatibilizing agents for use in the fuel conditioner component of the instant invention are organic compounds of moderate solubility parameter and moderate to strong hydrogen-bonding capacity. Solubility parameters, δ, based on cohesive energy density are a fundamental descriptor of an organic solvent giving a measure of its polarity. Simple aliphatic molecules of low polarity have a low δ of about 7.3; highly polar water has a high δ of 23.4. Solubility parameters, however, are just a first approximation to the polarity of an organic solvent. Also important to generalized polarity, and hence solvent power, are dipole moment and hydrogen-bonding capacity. Symmetrical carbon tetrachloride and some aromatics with low gross dipole moment and poor hydrogen-bonding capacity have a solubility parameter of about 8.5. In contrast, methyl propyl ketone has almost the same solubility parameter, 8.7, but quite strong hydrogen-bonding capacity and a definite dipole moment. Thus, no one figure of merit alone describes the “polarity” of an organic solvent.
For the practice of the present invention a compatibilizing agent preferably having a solubility parameter from about 7.0 to about 14.0 and moderate to strong hydrogen-bonding capacity. Suitable classes of organic solvents are alcohols, ketones, esters, and ethers. Preferred compatibilizing agents are straight-chain, branched-chain, and alicyclic alcohols with from six to 14 carbon atoms. Especially preferred compounds for compatibilizing agents are the hexanols, the heptanols, the octanols, the nonyl alcohols, the decanols, and the dodecanols.
The fuel conditioner component of this invention may additionally include a hydrophilic separant which decreases the amount of water in the hydrocarbon fuel, thus improving combustion. Suitable separants for practicing the current invention are ethers of glycols or polyglycols, especially monoethers. Monoethers are preferred over diethers in the practice of the present invention.
Examples of such compounds which may be used are the monoethers of ethylene glycol, propylene glycol, trimethylene glycol, alphabutylene glycol, 1,3-butanediol, beta-butylene glycol, isobutylene glycol, tetramethylene glycol, hexylene glycol, diethylene glycol, dipropylene glycol, tripropylene glycol, triethylene glycol, tetraethylene glycol, 1,5-pentanediol, 2-methyl-2-ethyl-1,3-propanediol, 2-ethyl-1,3-hexanediol. Some monoethers include ethylene glycol monophenyl ether, ethylene glycol monomethylether, ethylene glycol monoethyl ether, ethylene glycol mono-(n-butyl) ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-(n-butyl) ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, diethylene glycol monocyclohexylether, ethylene glycol monobenzyl ether, triethylene glycol monophenethyl ether, butylene glycol mono-(p-(n-butoxy) phenyl) ether, trimethylene glycol mono(alkylphenyl) ether, tripropylene glycol monomethyl ether, ethylene glycol mono-isopropyl ether, ethylene glycol monoisobutyl ether, ethylene glycol monohexyl ether, triethylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, 1-butoxyethoxy-2-propanol, monophenyl ether of polypropylene glycol having an average molecular weight of about 975 to 1075, and monophenyl ether of polypropylene glycol wherein the polyglycol has a average molecular weight of about 400 to 450, monophenyl ether of polypropylene glycol wherein the polypropylene glycol has an average molecular weight of about 975 to 1075. Such compounds are sold commercially under trade names such as Butyl CELLOSOLVE, Ethyl CELLOSOLVE, Hexyl CELLOSOLVE, Methyl CARBITOL, Butyl CARBITOL, DOWANOL Glycol ethers, and the like.
The composition of this invention may additionally comprise a suitable amount of a carrier oil or fluidizer selected from the group consisting of petroleum-based oils, mineral oils, polypropylene compounds having a molecular weight in the range of about 500 to about 3000, polyisobutylene compounds having a molecular weight in the range of about 500 to about 3000, polyoxyalkylene compounds having a molecular weight in the range of about 500 to about 3000, and polybutyl and polyisobutyl alcohols containing polybutyl or polyisobutyl radicals derived from polyisobutene and up to 20% by weight of n-butene, corresponding carboxylates of the polybutyl or polyisobutyl alcohol, and mixtures thereof. Petroleum based oils which may be employed include top cylinder oils as well as both natural and synthetic naphthenic and paraffinic base stock oils of relatively high viscosity, including so-called Solvent Neutral Oils (SNO) such as SNO-500 and SNO-600. Mineral oils which may be employed include so-called “light” mineral oils, i.e. those petroleum, aliphatic or alicyclic fractions having a viscosity less than about 10,000 SUS at 250° C. A mixture of hydrocarbon fractions may also be employed in place of a base stock. The above-described polybutyl and polyisobutyl alcohols include those disclosed in U.S. Pat. No. 4,859,210 (Franz et al.), incorporated herein by reference. As used in this description and in the appended claims, the terms “carrier oil” and “fluidizer” are interchangeable, as will be readily understood by those skilled in the art.
Given the presence of the many constituents described above, a wide variety of proportions are suitable for the additive composition of this invention. Below a “Useful Range” and a “Preferred Range” are given in weight percent, based upon the total weight of the additive composition:
The additive composition of this invention may be employed in a wide variety of biodiesel containing fuels for a variety of engines. Preferred biodiesel fuel compositions for use with the additive composition of this invention are those intended for use in glow plug ignition internal combustion diesel engines. Such biodiesel fuel compositions comprise a desired percentage of biodiesel in the range of from about 2% to about 100% in admixture with petroleum based diesel fuel stocks. In addition, the biodiesel fuel composition may additionally comprise other additives typically employed in biodiesel fuels, such as anti-icing additives, upper cylinder lubricating oils, carburetor detergents, anti-corrosion additives, de-emulsifying agents, odor suppressors, and the like.
Throughout the specification, examples and claims the following definitions are used.
Cetane Number (CN) means the measure of ignition quality of diesel fuel based on ignition delay in an engine. The higher the Cetane number is the shorter the ignition delay and the better the ignition quality.
Cloud Point means the temperature at which a sample of a petroleum product just shows a cloud or haze of wax crystals when it is cooled under standard test conditions, as defined in ASTM D 2500.
Pour Point means the lowest temperature at which a petroleum product will just flow when tested under standard conditions, as defined in ASTM D97.
ASTM means the American Society for Testing and Materials.
The advantages of using additive composition to biodiesel fuels include lowering HC emissions, lowering CO emissions, significantly reducing PM emissions thus providing much lower smoke and particulate emissions, accelerating combustion process thereby improving fuel economy and reduced engine noise, reducing cold start and gum formation tendencies, and reduces deposit formation in engines.
