Patent Application
20060101712
Not applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
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The present disclosure relates generally to fuels, and in particular environmentally friendly or “green” fuels. More particularly, the present disclosure relates to off-road engine fuels suitable for use in 2-cycle and 4-cycle engines and having low toxic emissions.
Cleaner alternatives to existing commercial gasoline would reduce the pollution associated with use of off-road engines such as 2-cycle and 4-cycle engines, and thereby help to temper restrictions on use of off-road engines that are being considered. Consideration has been given to limiting the use of off-road 2-cycle and 4-cycle engines, such as are used in landscape maintenance, due to pollution and smog generation. For example, science indicates that the precursors to ozone emitted from these engines may have less of an impact after 2:00 PM daily. Banning commercial mowing and landscape maintenance would in many ways result in a significant and undesirable economic impact. Use of cleaner fuels in any small, off-road engines, such as used in snowmobiles, jet skis, portable generators, 2-wheel and 4-wheel all-terrain vehicles, chain saws, wood chippers, and the like, would help counteract any negative economic impact while reducing pollution. In addition to reducing pollution, cleaner fuels would reduce toxin and exhaust emissions, which would reduce harmful effects on the operators of such off-road engines. Thus, an ongoing need exists for cleaner, affordable off-road engine fuels that reduce levels of pollutants and toxins.
In various embodiments, provided is an off-road engine fuel comprising less than or equal to about 1 liquid volume percent aromatic hydrocarbons according to ASTM D-1319. In embodiments, the fuel may further comprise a specific gravity effective for employment of the fuel in 2-cycle and 4-cycle off-road engines. In other embodiments, the fuel may further comprise a specific gravity according to ASTM D-4052 from about 0.6 to about 0.8. The fuel may further comprise from about 0.5 to about 50 liquid volume percent naphthenes. In embodiments, the fuel comprises hydrocarbons having from about 4 to about 13 carbon atoms. In some embodiments the fuel further comprises less than or equal to about 1 liquid volume percent olefins according to ASTM D-1319; less than or equal to about 0.1 liquid volume percent benzene according to ASTM D-1319; less than or equal to about 10 ppm by weight sulfur according to ASTM D-5453; equal to or greater than about 85 liquid volume percent saturated hydrocarbons according to ASTM D-1319; or combinations thereof. The fuel may also comprise oxygenates; for example from about 2 liquid volume percent to about 25 liquid volume percent oxygenates.
In embodiments, combustion of the fuel yields emissions of benzene, 1,3-butadiene, formaldehyde, and acetaldehyde during engine operation that are at least about 40 percent less than emissions of benzene, 1,3-butadiene, formaldehyde, and acetaldehyde from combustion of a reference standard fuel according to the 6 mode California Air Resources Board Small Off Road Engine test. Further, the fuel may yield emissions of benzene during engine operation that are at least about 75 percent less than emissions of benzene from a reference standard fuel according to the 6 mode California Air Resources Board Small Off Road Engine test; emissions of 1,3-butadiene from an oxygenated fuel during engine operation that are at least about 20 percent less than emissions of 1,3-butadiene from a reference standard fuel according to the 6 mode California Air Resources Board Small Off Road Engine test; emissions of 1,3-butadiene during operation of a 2-cycle engine that are at least about 15 percent less than emissions of 1,3-butadiene from a reference standard fuel according to the 6 mode California Air Resources Board Small Off Road Engine test; emissions of particulate matter from an oxygenated fuel during operation of a 2-cycle engine that are at least about 20 percent less than emissions of particulate matter from a reference standard fuel according to the 6 mode California Air Resources Board Small Off Road Engine test; emissions of oxides of nitrogen during operation of a 2-cycle engine that are at least about 15 percent less than emissions of oxides of nitrogen from a reference standard fuel according to the 6 mode California Air Resources Board Small Off Road Engine test; emissions of carbon monoxide from an oxygenated fuel during engine operation that are at least about 12 percent less than emissions of carbon monoxide from a reference standard fuel according to the 6 mode California Air Resources Board Small Off Road Engine test; emissions of hydrocarbons from an oxygenated fuel during engine operation are at least about 1.5 percent less than emissions of a reference standard fuel according to the 6 mode California Air Resources Board Small Off Road Engine test; or combinations thereof.
In various embodiments, a method disclosed comprises selecting a first hydrocarbon stream comprising equal to or greater than about 99 liquid volume percent saturated hydrocarbons having from about 4 to about 9 carbon atoms; combining from about 5 liquid volume percent to about 85 liquid volume percent of the first hydrocarbon stream with from about 2 liquid volume percent to about 10 liquid volume percent of a second hydrocarbon stream comprising at least about 50 weight percent naphthenes; and formulating an off-road engine fuel from a mixture comprising the first hydrocarbon stream and second hydrocarbon stream. In further embodiments, the first hydrocarbon stream is combined with from about 0 liquid volume percent to about 25 liquid volume percent of an oxygenate; with a third hydrocarbon stream comprising equal to or greater than about 99.5 liquid volume percent saturated hydrocarbons having from about 6 to about 8 carbon atoms; with from about 0 liquid volume percent to about 10 liquid volume percent of an n-butane stream; with from about 0 liquid volume percent to about 10 liquid volume percent of an isopentane stream; with from about 0 liquid volume percent to about 20 liquid volume percent of an isohexane stream; with from about 0 liquid volume percent to about 25 liquid volume percent of a heptane stream; with from about 0 liquid volume percent to about 25 liquid volume percent of a fourth hydrocarbon stream comprising at least 99 weight percent isoparaffins having from about 9 to about 11 carbon atoms; with oil for use of the off-road engine fuel in an engine; or combinations thereof.
In some embodiments, a method is provided for packaging the fuel in units of less than or equal to about 10 gallons; and selling the fuel for use in off-road 2-cycle and 4-cycle engines. The method may further comprise selling the fuel in retail stores.
Described herein are off-road engine fuels (“fuels” or “green fuels”) and methods of formulating and using such fuels. Such off road fuels are appropriate for use in commercially available 2-cycle and 4-cycle off-road engines. An off-road engine fuel in accordance with the present disclosure may comprise a mixture (or “blend”) of various hydrocarbon streams having hydrocarbons with from about 4 to about 13 carbon atoms. The particular hydrocarbon streams (i.e., fuel constituents, feedstocks, or blendstocks) combined to form the fuel are generally selected such that the fuel has desirable physical properties, composition, combustion characteristics, or combinations thereof as described herein.
In an embodiment, the fuel has a Reid vapor pressure (RVP) that is appropriate for ‘regular summer gasoline’ as the term is known to a person skilled in the art, alternatively an RVP of from about 7 to about 9 pounds according to ASTM D-4814. In embodiments, the fuel comprises a boiling point range from about 90 to about 360 degrees Fahrenheit according to ASTM D-86. Further, the fuel constituents may be selected such that the fuel possesses an anti-knock index, or (R+M)/2 octane, that falls within a range from about 82 to about 92.
The specific gravity of the fuel may impact its operability in commercially available 2-cycle and 4-cycle engines. In an embodiment, the off-road engine fuel described herein comprises a specific gravity effective for employment of the fuel in commercial 2-cycle and 4-cycle off-road engines; alternatively, the fuel comprises a specific gravity according to ASTM D-4052 of from about 0.6 to about 0.8; alternatively, the specific gravity is from about 0.65 to about 0.75; alternatively, from about 0.675 to about 0.725. The specific gravity may be adjusted depending upon the particular combination of hydrocarbons present in the fuel.
In an embodiment, the green fuel comprises equal to or greater than about 50 mole percent paraffins having from about 4 to about 13 carbon atoms, and equal to or greater than about 2 mole percent naphthenes having from about 4 to about 12 carbon atoms; alternatively, equal to or greater than about 75 mole percent paraffins and equal to or greater than about 6 mole percent naphthenes; alternatively, equal to or greater than about 85 mole percent paraffins and equal to or greater than about 11 mole percent naphthenes. As used herein, paraffins may include isoparaffins. In another embodiment, the fuel comprises less than or equal to 5 mole percent aromatic hydrocarbons; alternatively, less than or equal to 1 mole percent; alternatively, less than or equal to 0.5 mole percent. In another embodiment, the fuel comprises less than or equal to 5 mole percent olefins; alternatively, less than or equal to 1 mole percent; alternatively, less than or equal to 0.5 mole percent. In an embodiment, a green fuel has a hydrocarbon distribution equal or similar to that shown in Table 1, alternatively ±5 percent, alternatively ±3 percent, alternatively ±1 percent.
In another embodiment, a green fuel comprises the properties shown in Table 2.
In some embodiments, inclusion of an oxygenate in the fuel reduces emissions from the fuel during engine operation. In embodiments, the oxygenated green fuel comprises from about 2 to about 25 liquid volume percent oxygenates; alternatively, from about 8 to about 17 liquid volume percent oxygenates; alternatively, from about 10 to about 14 liquid volume percent oxygenates. In terms of oxygen content, in embodiments the fuel may comprise from about 0.5 to about 5 weight percent oxygen; alternatively, from about 1 to about 3.5 weight percent oxygen; alternatively, from about 1.7 to about 2.7 weight percent oxygen. Suitable oxygenates may comprise tert-butyl alcohol, n-butanol, methanol, n-propanol, isopropanol, TAME, DIPE, DNPE, DNBE, ethyl ether, MTBE, ethanol (EtOH), ethyl tert-butyl ether (ETBE), or combinations thereof. In certain embodiments, the oxygenates comprise EtOH, ETBE, or combinations thereof.
In embodiments comprising oxygenates, the oxygenated fuel may comprise equal to or greater than about 50 mole percent paraffins having from about 4 to about 13 carbon atoms, equal to or greater than about 2 mole percent naphthenes having from about 4 to about 12 carbon atoms, and equal to or greater than about 3 mole percent oxygenates; alternatively, equal to or greater than about 65 mole percent paraffins, equal to or greater than about 4 mole percent naphthenes, and equal to or greater than about 8 mole percent oxygenates; alternatively, equal to or greater than about 77 mole percent paraffins, equal to or greater than about 6 mole percent naphthenes, and equal to or greater than about 12 mole percent oxygenates. In an embodiment, an oxygenated green fuel has a hydrocarbon distribution equal or similar to that shown in Table 3, alternatively ±5 percent, alternatively ±3 percent, alternatively ±1 percent.
In another embodiment, an oxygenated green fuel comprises the properties exhibited in Table 4.
Hydrocarbon streams that make up the off-road engine fuel are selected such that the fuel comprises limited levels of one or more pollutants and toxic compounds. In various embodiments, the fuel may comprise from about 0 to about 10 liquid volume percent aromatic hydrocarbons according to ASTM D-1319; alternatively, less than or equal to about 1 liquid volume percent aromatic hydrocarbons; alternatively, less than or equal to about 0.5 liquid volume percent aromatic hydrocarbons. In other embodiments, the fuel may comprise from about 0 to about 10 liquid volume percent olefins according to ASTM D-1319; alternatively, less than or equal to about 1 liquid volume percent olefins; alternatively, less than or equal to about 0.5 liquid volume percent olefins. In yet other embodiments, the fuel may comprise from about 0 to about 1 liquid volume percent benzene according to ASTM D-3606, D-4420, or other available chromatography method; alternatively, less than or equal to about 0.1 liquid volume percent benzene; alternatively, less than or equal to about 0.05 liquid volume percent benzene. In still other embodiments, the fuel may comprise less than or equal to about 10 parts per million by weight sulfur according to ASTM D-5453; alternatively, about 5 parts per million by weight sulfur; alternatively, about 1.5 parts per million by weight. In embodiments, the fuel may comprise any number of combinations of the above limited levels of aromatic hydrocarbons, olefins, benzene, and sulfur.
The level of saturation among the hydrocarbons in the fuel may be indicative of the lack of pollutants and toxins in the fuel. In embodiments, the fuel comprises equal to or greater than about 85 liquid volume percent saturated hydrocarbons according to ASTM D-1319; alternatively, equal to or greater than about 90 liquid volume percent; alternatively, equal to or great than about 98 liquid volume percent.
In embodiments, the fuel comprises from about 0.5 to about 50 liquid volume percent naphthenes; alternatively, from about 2 to about 20 liquid volume percent naphthenes; alternatively, from about 5 to about 14 liquid volume percent. In some embodiments, naphthenes comprise various substituted cyclic hydrocarbons, un-substituted cyclic hydrocarbons, or combinations thereof. In certain embodiments, naphthenes comprise cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, or combinations thereof.
In various embodiments, use of the green fuel in various engines reduces emissions of certain toxic compounds during combustion as compared to the emissions from a reference standard fuel (or “reference fuel”). Such a reference fuel may be, for example, a fluid designated by a governmental or regulatory agency as being acceptable for common private and commercial use in commercially available 2-cycle and 4-cycle engines. In embodiments, the reference fuel comprises an RVP in compliance with ASTM D-4814, the governing specification for commercial gasoline in the United States. In other embodiments, the reference fuel meets the certification standards for a regular commercial gasoline according to ASTM D-1319. In certain embodiments, the reference fuel exhibits the composition and properties provided in Tables 5a and 5b wherein IBP represents initial boiling point and EP represents end point:
An example of a suitable reference fuel is the Unleaded Test Gasoline Regular Grade (UTG-91) manufactured by Chevron Phillips Chemical Company.
In embodiments, emissions of certain EPA-designated toxic compounds from the green fuel during engine operation are less than emissions of similar toxic compounds from the reference fuel. In some embodiments, emissions of benzene, 1,3-butadiene, formaldehyde, and acetaldehyde from the green fuel during engine operation are less than emissions of the same toxic compounds from the reference fuel according to the 6 mode California Air Resources Board Small Off Road Engine Test (CARBT). In certain embodiments, emissions of benzene, 1,3-butadiene, formaldehyde, and acetaldehyde from the green fuel during engine operation are at least about 40 percent less than emissions of the same toxic compounds from the reference fuel according to CARBT; alternatively, emissions of such compounds are at least about 45 percent less than similar emissions from the reference fuel; alternatively, emissions are at least about 55 percent less.
In an embodiment, emissions of benzene from the green fuel during engine operation are at least about 75 percent less than emissions of benzene from the reference standard fuel according to CARBT; alternatively, at least about 80 percent less; alternatively, at least about 88 percent less. In an embodiment, emissions of 1,3-butadiene from the oxygenated green fuel during engine operation are at least about 20 percent less than emissions of 1,3-butadiene from the reference standard fuel according to CARBT; alternatively, at least about 30 percent less; alternatively, at least about 40 percent less. In an embodiment, emissions of 1,3-butadiene from the green fuel during operation of a 2-cycle engine are at least about 15 percent less than emissions of 1,3-butadiene from the reference standard fuel according to CARBT; alternatively, at least about 20 percent less; alternatively, at least about 23 percent less.
Use of the green fuel and oxygenated green fuel may further reduce emissions of other compounds, such as particulate matter, oxides of nitrogen, carbon monoxide, and hydrocarbons. In an embodiment, emissions of particulate matter from the green fuel during operation of a 2-cycle engine are at least about 2 percent less than emissions of particulate matter from the reference standard fuel according to CARBT; alternatively, at least about 3 percent less; alternatively, at least about 4.7 percent less. In an embodiment, emissions of particulate matter from the oxygenated green fuel during operation of a 2-cycle engine are at least about 20 percent less than emissions of particulate matter from the reference standard fuel according to CARBT; alternatively, at least about 25 percent less; alternatively, at least about 28 percent less. In an embodiment, emissions of oxides of nitrogen from the green fuel during operation of a 2-cycle engine are at least about 15 percent less than emissions of oxides of nitrogen from the reference standard fuel according to CARBT; alternatively, at least about 20 percent less; alternatively, at least about 24 percent less. In an embodiment, emissions of carbon monoxide from the oxygenated green fuel during engine operation are at least about 12 percent less than emissions of carbon monoxide from the reference standard fuel according to CARBT; alternatively, at least about 17 percent less; alternatively, at least about 22 percent less. In an embodiment, emissions of hydrocarbons from the oxygenated green fuel during engine operation are at least about 1.5 percent less than emissions of hydrocarbons from the reference standard fuel according to CARBT; alternatively, at least about 5 percent less; alternatively, at least about 9 percent less.
Use of the green fuel and oxygenated green fuel may also reduce the ozone formation potential of emissions and, specifically, volatile organic compound (VOC) emissions, during engine operation and refueling. In an embodiment, the ozone formation potential of emissions from the oxygenated green fuel during engine operation is at least about 2 percent less than the ozone formation potential of emissions from the reference standard fuel according to the test method described by Siegl, Walter O., et al, “Improved Speciation Methodology for Phase III for the Auto/oil Air Quality Improvement Research Program,” SAE 930142, 1993 (or “SAE 930142”); alternatively, at least about 15 percent less; alternatively, at least about 29 percent less. In an embodiment, the ozone formation potential of emissions from the oxygenated green fuel during operation of a 2-cycle engine is at least about 20 percent less than the ozone formation potential of emissions from the reference standard fuel according to SAE 930142; alternatively, at least about 25 percent less; alternatively, at least about 27 percent less. In an embodiment, the ozone formation potential of emissions from the green fuel during operation of a 2-cycle engine is at least about 10 percent less than the ozone formation potential of emissions from the reference standard fuel according to SAE 930142; alternatively, at least about 15 percent less; alternatively, at least about 18 percent less. In an embodiment, the ozone formation potential of VOC emissions from the green fuel during refueling is at least about 5 percent less than the ozone formation potential of VOC emissions from the reference standard fuel according to SAE 930142; alternatively, at least about 8 percent less; alternatively, at least about 11.5 percent less.
An off-road engine fuel in accordance with the present disclosure may comprise a mixture (or “blend”) of various hydrocarbon streams having hydrocarbons with from about 4 to about 13 carbon atoms. The particular hydrocarbon streams (i.e., fuel constituents, feedstocks, or blendstocks) combined to form the fuel are generally selected such that the fuel has a desired combination of physical properties, composition, combustion characteristics, or combinations thereof as described herein.
In embodiments, a first hydrocarbon stream employed in formulating the green fuel comprises hydrocarbons having from about 4 to about 9 carbon atoms. In certain embodiments, the first hydrocarbon stream is a HF light alkylate stream comprising hydrocarbons having from about 4 to about 9 carbon atoms. In an embodiment, a first hydrocarbon stream has a hydrocarbon distribution equal or similar to that shown in Table 6, alternatively ±5 weight percent, alternatively ±3 weight percent, alternatively ±1 weight percent.
In another embodiment, a first hydrocarbon stream comprises the properties shown in Table 7.
In some embodiments, the first hydrocarbon stream employed in formulating the green fuel comprises less than or equal to about 10 parts per million by weight sulfur according to ASTM D-5453; alternatively, about 5 parts per million by weight sulfur; alternatively, about 2 parts per million by weight. In embodiments, the first hydrocarbon stream further comprises from about 0 to about 5 liquid volume percent aromatic hydrocarbons according to ASTM D-1319; alternatively, less than or equal to about 1 liquid volume percent aromatic hydrocarbons; alternatively, less than or equal to about 0.5 liquid volume percent aromatic hydrocarbons. In other embodiments, the first hydrocarbon stream further comprises from about 0 to about 5 liquid volume percent olefins according to ASTM D-1319; alternatively, less than or equal to about 1 liquid volume percent olefins; alternatively, less than or equal to about 0.5 liquid volume percent olefins. In yet other embodiments, the first hydrocarbon stream further comprises from about 0 to about 1 liquid volume percent benzene according to ASTM D-3606, D-4420, or other available chromatography method; alternatively, less than or equal to about 0.1 liquid volume percent benzene; alternatively, less than or equal to about 0.05 liquid volume percent benzene.
In various embodiments, a second hydrocarbon stream comprising naphthenes is employed in formulating the green fuel. In some embodiments, the second hydrocarbon stream comprises substituted cyclic hydrocarbons, unsubstituted cyclic hydrocarbons, or combinations thereof. In certain embodiments, the second hydrocarbon stream comprises naphthenes having from about 4 to about 11 carbon atoms. In other embodiments, naphthenes in the second hydrocarbon stream comprise substituted naphthenes, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, or combinations thereof. In an embodiment, naphthenes in the second hydrocarbon stream comprise the properties shown in Table 8.
In some embodiments, a third hydrocarbon stream is employed in formulating the green fuel. In embodiments, the third hydrocarbon stream comprises equal to or greater than about 99.5 liquid volume percent saturated hydrocarbons having from about 6 to about 8 carbon atoms. In an embodiment, a third hydrocarbon stream has a hydrocarbon distribution equal or similar to that shown in Table 9, alternatively ±5 weight percent, alternatively ±3 weight percent, alternatively ±1 weight percent.
In another embodiment, a third hydrocarbon stream comprises the properties shown in Table 10.
In certain embodiments, the third hydrocarbon stream further comprises from about 0 to about 2 liquid volume percent aromatic hydrocarbons according to ASTM D-1319; alternatively, less than or equal to about 1 liquid volume percent aromatic hydrocarbons; alternatively, less than or equal to about 0.5 liquid volume percent aromatic hydrocarbons. In other embodiments, the third hydrocarbon stream further comprises from about 0 to about 2 liquid volume percent olefins according to ASTM D-1319; alternatively, less than or equal to about 1 liquid volume percent olefins; alternatively, less than or equal to about 0.5 liquid volume percent olefins. In yet other embodiments, the third hydrocarbon stream further comprises from about 0 to about 0.5 liquid volume percent benzene according to ASTM D-3606, D-4420, or other available chromatography method; alternatively, less than or equal to about 0.1 liquid volume percent benzene; alternatively, less than or equal to about 0.05 liquid volume percent benzene.
In embodiments, a n-butane stream is employed in formulating the green fuel. In an embodiment, the n-butane stream comprises at least about 80 weight percent n-butane; alternatively, at least about 90 weight percent n-butane; alternatively, at least about 95 weight percent n-butane. In an embodiment, a n-butane stream has a hydrocarbon distribution equal or similar to that shown in Table 11, alternatively ±5 weight percent, alternatively ±3 weight percent, alternatively ±1 weight percent.
In embodiments, an isopentane stream is employed in formulating the green fuel. In an embodiment, the isopentane stream comprises at least about 70 weight percent isopentane; alternatively, at least about 85 weight percent isopentane; alternatively, at least about 96 weight percent isopentane. In an embodiment, an isopentane stream has a hydrocarbon distribution equal or similar to that shown in Table 12, alternatively ±5 weight percent, alternatively ±3 weight percent, alternatively ±1 weight percent.
In embodiments, an isohexane stream is employed in formulating the green fuel. In an embodiment, the isohexane stream comprises at least about 80 weight percent isohexanes; alternatively, at least about 90 weight percent isohexanes; alternatively, at least about 99 weight percent isohexanes; alternatively, about 100 weight percent isohexanes.
In embodiments, a heptane stream is employed in formulating the green fuel. In an embodiment, the heptane stream comprises at least about 50 weight percent heptanes; alternatively, at least about 70 weight percent heptanes; alternatively, at least about 80 weight percent heptanes. For purposes of the present application, “heptanes” refers to both normal heptane and isomers of heptane. In an embodiment, a heptane stream has a hydrocarbon distribution equal or similar to that shown in Table 13, alternatively ±5 weight percent, alternatively ±3 weight percent, alternatively ±1 weight percent.
In another embodiment, a heptane stream comprises the properties shown in Table 14.
In some embodiments, a fourth hydrocarbon stream is employed in formulating the green fuel. In embodiments, the fourth hydrocarbon stream comprises at least about 99 weight percent isoparaffins having from about 9 to about 11 carbon atoms. In an embodiment, a fourth hydrocarbon stream has a hydrocarbon distribution equal or similar to that shown in Table 15, alternatively ±5 weight percent, alternatively ±3 weight percent, alternatively ±1 weight percent.
In certain embodiments, the fourth hydrocarbon stream further comprises from about 0 to about 2 liquid volume percent aromatic hydrocarbons according to ASTM D-1319; alternatively, less than or equal to about 1 liquid volume percent aromatic hydrocarbons; alternatively, less than or equal to about 0.05 liquid volume percent aromatic hydrocarbons. In other embodiments, the fourth hydrocarbon stream further comprises from about 0 to about 2 liquid volume percent olefins according to ASTM D-1319; alternatively, less than or equal to about 1 liquid volume percent olefins; alternatively, less than or equal to about 0.05 liquid volume percent olefins. In yet other embodiments, the fourth hydrocarbon stream further comprises from about 0 to about 0.5 liquid volume percent benzene according to ASTM D-3606, D-4420, or other available chromatography method; alternatively, less than or equal to about 0.1 liquid volume percent benzene; alternatively, less than or equal to about 0.05 liquid volume percent benzene.
In some embodiments, a fifth hydrocarbon stream is employed in formulating the green fuel. In embodiments, the fifth hydrocarbon stream comprises at least about 99 weight percent isoparaffins having from about 11 to about 13 carbon atoms. In an embodiment, a fifth hydrocarbon stream has a hydrocarbon distribution equal or similar to that shown in Table 16, alternatively ±5 weight percent, alternatively ±3 weight percent, alternatively ±1 weight percent.
With the teachings provided in the present application one of skill in the art will recognize that many combinations of various hydrocarbon streams may be mixed to achieve the characteristics of the disclosed green fuel. Further, the source or sources of the hydrocarbon streams, and the sequence and timing with which the hydrocarbon streams are combined, may be selected to obtain a desired quality of the fuel (e.g., physical properties, composition, combustion characteristics, or combinations thereof). The particular combination, source(s), sequence, and timing employed in formulating the fuel may be driven by practical and/or cost considerations, such as feedstock availability, plant layout/design, and the like. Thus, the invention disclosed in the present application is not limited to the specific embodiments and examples of formulations, blendstocks, and blending sequences described. In various embodiments, the green fuel is formulated by combining one or more hydrocarbon streams comprising fully saturated hydrocarbons having from about 4 to about 13 carbon atoms with one or more hydrocarbon streams comprising naphthenes having from about 4 to about 11 carbon atoms. Examples of such hydrocarbon streams introduced herein are the first hydrocarbon stream, second hydrocarbon stream, third hydrocarbon stream, fourth hydrocarbon stream, heptane stream, isopentane stream, isohexane stream, and n-butane stream.
In some embodiments, a method is disclosed comprising selecting a first hydrocarbon stream comprising equal to or greater than about 99 liquid volume percent hydrocarbons having from about 4 to about 9 carbon atoms; combining from about 5 liquid volume percent to about 85 liquid volume percent of the first hydrocarbon stream with from about 2 liquid volume percent to about 10 liquid volume percent of a second hydrocarbon stream comprising at least about 50 weight percent naphthenes; and formulating the off-road engine fuel from a mixture comprising the first hydrocarbon stream and second hydrocarbon stream.
In embodiments, the fuel is further combined with from about 0 to about 25 liquid volume percent oxygenate; alternatively, from about 8 to about 17 liquid volume percent oxygenate; alternatively, from about 10 to about 14 liquid volume percent oxygenate. In an embodiment, the fuel is further combined with ETOH, ETBE, or combinations thereof.
In some embodiments, from about 5 to about 85 liquid volume percent of a third hydrocarbon stream is added to a green fuel formulation; alternatively, from about 25 to about 50 liquid volume percent of a third hydrocarbon stream is added; alternatively, from about 30 to about 40 liquid volume percent of a third hydrocarbon stream is added. In an embodiment, the third hydrocarbon stream comprises equal to or greater than about 99.5 liquid volume percent saturated hydrocarbons having from about 6 to about 8 carbon atoms.
In embodiments, from about 0 to about 10 liquid volume percent of a n-butane stream is added to a green fuel formulation; alternatively, from about 0.75 to about 5 liquid volume percent of a n-butane stream is added; alternatively, from about 1 to about 3 liquid volume percent of a n-butane stream is added.
In other embodiments, from about 0 to about 10 liquid volume percent of an isopentane stream is added to a green fuel formulation; alternatively, from about 1 to about 5 liquid volume percent of an isopentane stream is added; alternatively, from about 2 to about 4 liquid volume percent of an isopentane stream is added.
In still other embodiments, from about 0 to about 20 liquid volume percent of an isohexane stream is added to a green fuel formulation; alternatively, from about 3 to about 16 liquid volume percent of an isohexane stream is added; alternatively, from about 7 to about 12 liquid volume percent of an isohexane stream is added.
In yet other embodiments, from about 0 to about 25 liquid volume percent of a heptane stream is added to a green fuel formulation; alternatively, from about 3 to about 18 liquid volume percent of a heptane stream is added; alternatively, from about 7 to about 12 liquid volume percent of a heptane stream is added.
In some embodiments, from about 0 to about 25 liquid volume percent of a fourth hydrocarbon stream is added to a green fuel formulation; alternatively, from about 4 to about 20 liquid volume percent of a fourth hydrocarbon stream is added; alternatively, from about 8 to about 14 liquid volume percent of a fourth hydrocarbon stream is added. In an embodiment, the fourth hydrocarbon stream comprises equal to or greater than about 99 weight percent isoparaffins having from about 9 to about 11 carbon atoms.
In some embodiments, from about 0 to about 5 liquid volume percent of a fifth hydrocarbon stream is added to a green fuel formulation. In an embodiment, the fifth hydrocarbon stream comprises equal to or greater than about 99 weight percent isoparaffins having from about 11 to about 13 carbon atoms.
In certain embodiments, the first hydrocarbon stream may be further combined with oil for use of the green fuel in 2-cycle engines. In an embodiment, the type of oil and ratio of green fuel combined with oil is according to engine manufacturer specifications. In another embodiment, the ratio of green fuel to oil is about 40:1. An example of a suitable oil for mixing with the green fuel is the Synjex® 2-Cycle Motor Oil manufactured by ConocoPhillips Company. Table 17 presents typical physical properties of a suitable 2-cycle oil.
Further embodiments of methods may comprise selecting a first hydrocarbon stream comprising equal to or greater than about 99 liquid volume percent saturated hydrocarbons having from about 4 to about 9 carbon atoms; combining the first hydrocarbon stream with a second hydrocarbon stream comprising at least about 50 weight percent naphthenes; and formulating a fuel from a mixture comprising the first hydrocarbon stream and second hydrocarbon stream, wherein the fuel comprises a specific gravity according to ASTM D-4052 effective for use in 2-cycle and 4-cycle off-road engines.
The methods of combining the hydrocarbon streams and ingredients described above may be carried out in any number of sequences. Further, any number of combinations of the methods, hydrocarbon streams, and ingredients may be employed to achieve the desired characteristics of the green fuels.
Embodiments disclosed herein also include a method comprising packaging the fuel described herein in units of less than or equal to about 10 gallons, alternatively less than or equal to about 5 gallons, and selling the fuel for use in off-road engines. Such engines may comprise any 2-cycle or 4-cycle off-road engine, such as engines employed in snowmobiles, jet skis, watercraft, portable generators, 2-wheel all-terrain vehicles, 3-wheel all-terrain vehicles, 4-wheel all-terrain vehicles, dirt bikes, outboard boat motors, chain saws, wood chippers, mower tractors, push mowers, weed trimmers, blowers, power washers, brush shredders, line trimmers, chain saws, tillers, and the like. In an embodiment, the off-road engines are small off-road engines having a displacement of equal to or less than about 1 liter, alternatively equal to or less than about 0.75 liter, alternatively equal to or less than about 0.5 liter, or alternatively equal to or less than about 0.25 liter. Such engines are filled with the green fuel as disclosed herein and operated according to manufacturer's instructions. In an embodiment, the prepackaged fuel further comprises 2-cycle engine oil co-packaged therewith or pre-mixed with the fuel in one or more green ratios (e.g., prepackaged 32:1, prepackaged 40:1, etc.). In an embodiment, the method of packaging and selling comprises selling the fuel in retail stores, for example in racks or cages placed in a safe location.
The invention having been generally described, the following examples are given as particular embodiments of the invention and to demonstrate the practice and advantages thereof. It is understood that the examples are given by way of illustration and are not intended to limit the specification or the claims that follow in any manner. Particular data for the following examples were derived from the Developmental Fuels Emissions Evaluation, Final Report, performed by Southwest Research Institute; SwRI Project No. 03.10434; 28 May 2004.
The following examples, 1-2, compare various characteristics of an exemplary green fuel, oxygenated green fuel, and standard reference fuel. Table 18a shows the distributions of various constituents and compounds in an exemplary green fuel, oxygenated green fuel, and reference fuel, as were employed in examples 1-2. Table 18b shows various identifying properties for an exemplary green fuel, oxygenated green fuel, and reference fuel, as were employed in examples 1-2. Table 18c shows manufacturer specifications for each engine. The 4-stroke engines were operated with SAE 30W oil. A synthetic oil was blended with the fuels at the engine manufacturer's recommended 40:1 ratio for the 2-stroke engine.
Tables 19a through 19c compare emissions of selected toxic compounds from a green fuel, oxygenated green fuel, and reference standard fuel during operation of the tree off-road engines identified in Table 18c. Data were colledcted in accordance with 6 Mode California Air Resources Board Small Off-Road Engine test. Table 19a shows emissions data when operating the side-valve, 4-stroke engine, Table 19b shows emissions data when operating the overhead valve, 4-stroke engine, and Table 19c shows emissions data when operating the 2-stroke engine. The data in Tables 19a, 19b, and 19c show that emissions of certain compounds from the green fuel and oxygenated green fuel were generally lower compared to the reference standard fuel for all three engine types. In particular, the data show the green fuels will reduce aromatic hydrocarbon emissions by no less than 80 percent.
Table 20 expresses the emissions data for selected compounds in terms of the percent change in emissions compared to the reference fuel. The columns of emissions data under each fuel represent emissions from different engine types, plus the average emissions for each fuel across all engine types. The engine types were ‘side-valve, 4-stroke’ (SV4S), ‘overhead-valve, 4-stroke’ (OHV4S), and ‘2-stroke’ (2S). Particulate matter emissions data was not available for 4-stroke engines. Across fuels and engine types, the reduction in emissions of benzene ranged from 82.0 to 92.7 percent; the reduction in emissions of 1,3-butadiene ranged from 0.8 to 41.7.
While preferred embodiments of the invention have been shown and described, modifications thereof can be made by one skilled in the art without departing from the spirit and teachings of the invention. The embodiments and examples described herein are exemplary only, and are not intended to be limiting. Many variations and modifications of the invention disclosed herein are possible and are within the scope of the invention. Use of the term “optionally” with respect to any element of a claim is intended to mean that the subject element is required, or alternatively, is not required. Both alternatives are intended to be within the scope of the claim. Use of broader terms such as comprises, includes, having, etc. should be understood to provide support for narrower terms such as consisting of, consisting essentially of, comprised substantially of, etc.
Accordingly, the scope of protection is not limited by the description set out above but is only limited by the claims which follow, that scope including all equivalents of the subject matter of the claims. Each and every claim is incorporated into the specification as an embodiment of the present invention. Thus, the claims are a further description and are an addition to the preferred embodiments of the present invention. The discussion of a reference in the Description of Related Art is not an admission that it is prior art to the present invention, especially any reference that may have a publication date after the priority date of this application. The disclosures of all patents, patent applications, and publications cited herein are hereby incorporated by reference, to the extent that they provide exemplary, procedural or other details supplementary to those set forth herein.
