Jet Turbine Fuel Compositions and Methods of Making and Using the Same

Abstract

Formulated jet turbine fuels and methods of forming the same are described herein including a method of manufacturing a jet turbine fuel that includes hydrocarbon fluids.

Description

FIELD

The present disclosure generally relates to jet turbine fuel formulations. Specifically, the present disclosure relates to the combination of hydrocarbon streams and hydrotreating certain hydrocarbon streams to manufacture jet turbine fuels having specific characteristics.

BACKGROUND

Typically, jet turbine fuels are refined using traditional methods to meet certain specifications. These traditional refining methods produce jet turbine fuels that may not optimize the performance of the jets and other vehicles powered by those fuels.

SUMMARY

[We will fill this in once we get claims]

BRIEF DESCRIPTION OF DRAWINGS

These need to be revised.

FIG. 1 illustrates distillation curves for blend stocks.

FIG. 2 illustrates distillation curve data of formulated jet turbine fuels.

FIG. 3 illustrates density data for formulated jet turbine fuels.

FIG. 4 illustrates distillation curve data of blend stocks.

FIG. 5 illustrates distillation curves of jet turbine fuels.

FIG. 6 illustrates density data for formulated jet turbine fuels.

FIG. 7 illustrates hydrogen content for formulated jet turbine fuels.

FIG. 8 illustrates the net heat of combustion for formulated jet turbine fuels.

FIG. 9 illustrates distillation curve data of formulated jet turbine fuels.

DETAILED DESCRIPTION

Introduction and Definitions

A detailed description will now be provided. Each of the appended claims defines a separate invention, which for infringement purposes is recognized as including equivalents to the various elements or limitations specified in the claims. The disclosure that follows includes specific embodiments, versions and examples, but the disclosure is not limited to these embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the methods and compositions of matter disclosed when the information in this disclosure is combined with available information and technology.

Various terms as used herein are shown below. To the extent a term used in a claim is not defined below, it should be given the broadest definition skilled persons in the pertinent art have given that term as reflected in printed publications and issued patents at the time of filing. Further, unless otherwise specified, all compounds described herein may be substituted or unsubstituted and the listing of compounds includes derivatives thereof.

Further, various ranges and/or numerical limitations may be expressly stated below. It should be recognized that any ranges include iterative ranges of like magnitude falling within the expressly stated ranges or limitations.

Certain embodiments of the present invention relate to formulated jet fuel or jet turbine fuel. These terms are used interchangeably and refer to fuel used to power jet turbines, such as are used on airplanes, helicopters, and tanks.

Many of the current users of jet fuel use a jet fuel that meets the JP-4, JP-5, JP-8, Jet-A1, or Jet-A specification. Certain relevant chemical and physical property specifications for certain jet fuels are shown in Table 1 below.

TABLE 1
Property	JP-4 Limit	JP-5 Limit	JET-A	ASTM Method
Fuel Evaporated	—	205	max	205	max	D-86
10% (° C.)
Fuel Evaporated	100	max	—	—	D-86
20% (° C.)
End Point (° C.)	270	max	300	max	300	max	D-86
Density at 15° C.	0.751-.802	0.788-0.845	0.775-.840	D-1298
g/ml
Sulfur (ppm)	4000	max	4000	max	3000	max	D-4294
Mercaptan Sulfur	20	max	20	max	30	max	D-3227
(ppm)
Freezing Point	−58	max	−−46	max	−40	max	D-2386
(° C.)
Net Heat of	18,400	min	18,300	min	18,400		D-3338
Combustion
(BTU/lb)
Aromatics (vol %)	25	max	25	max	25	max	D-1319
Hydrogen content	13.5	min	13.4	min	—	D-3343
(wt %)
Flash Point (° F.)	140	min	140	min	100	min	D-93
	(60°	C.)	(60°	C.)	(38°	C.)
Smoke Point mm	20	19	25	D-1322

Traditionally, jet fuels and turbine fuels are derived from refined kerosene. Kerosene is generally obtained from the fractional distillation of petroleum between 140° C. and 275° C., resulting in a mixture of molecules with carbon chains lengths between 10 and 25 carbon atoms. Unlike traditional methods of manufacturing jet fuels, the fuels of the certain embodiments of the present disclosure are formulated by blending one or more hydrocarbon fluids to form formulated fuel.

As used herein, the term “hydrocarbon fluids” is used in a generic sense to describe a wide range of materials used in an equally wide range of applications. The hydrocarbon fluids generally utilized for the formulated jet fuels described herein may be produced by a number of processes. For example, hydrocarbon fluids can be produced from severe hydrotreating, deep hydrotreatment or hydrocracking to remove sulfur and other heteroatoms or polymerization or oligomerization process, such processes being followed by distillation to separate them into narrow boiling ranges. In some cases there may be additional steps, such as chemical or physical separation in order to concentrate a stream into isoparaffins or paraffins. Further, isoparaffins derived from oligomerization may constitute hydrocarbon fluids.

Certain hydrocarbon fluids are described in U.S. Pat. No. 7,311,814 and U.S. Pat. No. 7,056,869, which are incorporated by reference herein. Unlike fuels, hydrocarbon fluids tend to have a narrow boiling point range, e.g., less than 500° F. (260° C.), or 300° F. (148° C.) or 100° F. (37° C.), for example. Such narrow cuts provide a more narrow flash point range and provide for tighter viscosity, improved viscosity stability and defined evaporation specifications, as shown by the distillation curve, for example.

In certain embodiments, the hydrocarbon fluids may be produced by hydrocracking a vacuum gas oil distillate followed by fractionating and/or hydrogenating the hydrocracked vacuum gas oil. Such fluids may have an ASTM D86 boiling point range of from 212° F. (100° C.) to 752° F. (400° C.), wherein the individual hydrocarbon fluids may have the narrower boiling ranges described herein. The fluids may further have a naphthenic content of at least 40 wt. %, or 60 wt. % or 70 wt. %, for example. The fluids may further have an aromatics content of less than 2 wt. %, or 1.5 wt. % or 1.0 wt. %, as examples. The fluids may further have an aniline point below 212° F. (100° C.), or 205° F. (96° C.) or 200° F. (93° C.), for example.

In certain embodiments, the hydrocarbon fluids have low sulfur concentrations e.g., less than 30 ppm, or less than 15 ppm or less than 3 ppm, aromatics contents that are below 1.0 vol. %, or 0.5 vol. % or 0.1 vol. %, for example, relatively high net heats of combustion, and narrow distillation ranges. Further, depending on how the hydrocarbon fluid is processed and produced, the hydrocarbon fluid may be further characterized as predominantly paraffinic, isoparaffinic, or naphthenic (e.g., greater than 40 wt. %, or 50 wt. % or 60 wt. % or 80%). While such characterization may be helpful in blending to achieve desired densities and/or high net heats of combustion, such characterization is not a necessary condition for formulation of jet fuels.

Some illustrative, non-limiting chemical and physical property ranges characterizing various hydrocarbon fluids are shown in Table 2 below.

TABLE 2
Property	Range	ASTM Method
End Point (° F.)	250-600 or <525	D-86
	(121-315° C. or <273° C.)
Specific Gravity (60° F.)	0.760-0.825 or 0.79-0.81	D-1298
Sulfur (ppm)	0.1-5.0 or <3	D-5623
Mercaptan Sulfur (ppm)	<1 or <0.5	D-3227
Freezing Point (° F.)	−120 to −40 (−84 to −40° C.)	D-2386
Net Heat of Combustion	>18,250, >18,600, >18,750	D-240
(BTU/lb)
Aromatics (vol %)	0-1.0	D-1319
Olefins (vol %)	0-0.1	D-1319
Hydrogen content (wt %)	13.0-15.3	D-3343
Flash Point (° F.)	130-225, >140 (54-107° C.,	D-93
	>60° C.)

The hydrocarbon fluids can be derived from any suitable starting material that can result in materials that meet the final use requirements. It is to be noted that starting materials need not fall into final product boiling range, as in the gas oil case stated above. Thus, starting materials for production of hydrocarbon fluids can be gas oils or other high molecular weight material (that are further hydrocracked to lower molecular weight materials or deep hydrotreated to decrease sulfur content, materials that are normally classified as distillates, such as kerosene, straight run diesel, ultralow sulfur diesel, coker diesel (with sufficient hydroprocessing), or light cycle oil from FCC units, for example. Starting materials can be kerosene or gas oils from Gas to Liquid process or from biomass conversion processes. Additionally, the starting materials may be olefins to produce the hydrocarbon fluids, olefins being polymerized or oligomerized. In one or more embodiments, the starting materials may include propene, butene or combinations thereof, for example. In certain embodiments, hydrocarbon fluids can include gas oil, kerosene, straight run diesel, ultralow sulfur diesel, coker diesel, light cycle oil, hydrodewaxed gasoil or kerosene cuts, ethylene, propene, butene or combinations thereof.

In one or more embodiments, the hydrocarbon fluids are generally components selected from C₉-C₁₈ or narrower distillation cuts. Specific, non-limiting, examples of distillation cuts characterizing hydrocarbon fluids that may be blended to form the formulated fuels include SPIRDANE® (e.g., D-40 having a density of about 0.790 g/mL, a boiling range of 356° F.-419° F. (180-215° C.), flash point of 107.6° F. (42° C.) and D-60 having a density of about 0.770 g/mL, a boiling range of 311° F.-392° F. (155-200° C.), flash point of 145° F. (62° C.)), KETRUL® (e.g., D-70 having a density of about 0.817 g/mL, a boiling range of 381° F.-462° F. (193-238° C.), flash point of 160° F. (71° C.) and D-80 having a density of about 0.817 g/mL, a boiling range of 397° F.-465° F. (202-240° C.), flash point of 170.6° F. (77° C.)), HYDROSEAL® (e.g., G 232 H) and ISANE IP® fluids, commercially available from TOTAL FLUIDES, S.A., ISOPAR™ fluids, commercially available from ExxonMobil Chemical Corp. and IP2835, commercially available from Idemitsu Corp.

With the information and methods provided in this disclosure, it is possible to formulate a jet fuel with particular desired characteristics by blending hydrocarbon streams. In one or more embodiments, the formulated fuels include two or more hydrocarbon fluids. For example, in some embodiments, the formulated fuels include two hydrocarbon fluids. In other embodiments, the formulated fuel includes three hydrocarbon fluids. In still other embodiments, the formulated fuel includes four hydrocarbon fluids. Individual hydrocarbon fluids are chosen for formulation into fuels depending on how each contributes to the final properties of a jet fuel blend.

In one or more embodiments, the formulated fuel is formulated to exhibit a particular distillation curve or aspects of a particular distillation curve. For instance, in certain embodiments, the formulated fuel may be designed to have a front end within the fuel evaporated limits designated in Table 1 and an endpoint at or below the temperature of the endpoint specified in Table 1. In such an instance, a plurality of hydrocarbon fluids may be blended to create a formulated fuel that meets the jet fuel specifications for “fuel evaporated” and “end point.”

It is not necessary for the individual hydrocarbon fluids that are to be blended to each have particular fluid characteristics, such as end point or fuel evaporated, within the specification desired. That is, the formulated fuel may be formulated from a broad spectrum of hydrocarbon fluids that in and of themselves do not meet the desired specification. Further, known jet fuel formulations may be incorporated with the hydrocarbon fluid. By utilizing such combinations, a broader tailored property distribution is achievable. For example, a specific, non-limiting formulated fuel may be formed of a first hydrocarbon fluid having an end point higher than the desired specification while a second hydrocarbon fluid may have an end point below that of the desired specification to achieve a blend that has an end point that falls within the desired specification. Further, by selecting the individual hydrocarbon fluids, it may be possible to replicate a desired distillation curve within an acceptable margin.

While in certain circumstances a single hydrocarbon fluid may be used as a fuel, such as one that falls within or overlaps the distillation range for a particular fuel specification, the combination of two or more fluids results in greater flexibility in how closely it is possible to match the entirety of the desired distillation curve and property range. For instance, when matching two points within the specification for a given fuel grade distillation curve, for example the 10% and final point, it may not be necessary to match the entire JP-5, JP-4, JP-8, Jet-A1, or Jet-A fuel curve to be within the specification. However, by combining two or more hydrocarbon fluids, it is possible to achieve a formulated fuel that more closely matches the desired distillation curve, thereby improving performance or standardizing performance, for instance.

In addition to blending hydrocarbon fluids to reach certain points on a distillation curve, such as the fuel evaporated 10% and endpoint, hydrocarbon fluids may be blended to achieve numerous other characteristics. For instance, hydrocarbon fluids may be blended to achieve formulated fuels with certain cold flow properties such as pour point, cloud point, freeze point and viscosity. In other embodiments, hydrocarbon fluids may be blended to achieve certain fuel performance characteristics, such as density, hydrogen content, and net heat of combustion.

As an example, in some embodiments, hydrocarbon fluids that have a flash point below the JP-5 specification of 140° F. (60° C.) may be used in the formulation, but only in amounts that do not reduce the flash point of the final blend below the specification. Similarly, fluids with freeze points above the (−46° C.) maximum specification, such as those with a minor amount of aromatics, may be included in the blend as long as the final freeze point is below the JP-5 fuel specification value.

The use of hydrocarbon fluids from which aromatics have been reduced/removed yields another benefit to the fuel. In certain embodiments, the reduced amount of aromatics in the hydrocarbon fluid components leads to a higher net heat of combustion for the hydrocarbon fluids components used as blend stock. In certain embodiments, the combination of these high net heat of combustion hydrocarbon fluids results in a product that exceeds the 18,300 BTU/pound minimum specification of JP-5 fuel. In certain embodiments of the present disclosure, the net heat of combustion is greater than 18,300 BTU/lb or from 18,500 BTU/pound to 19,000 BTU per pound as measured by ASTM D-240. In other embodiments of the present disclosure, the net heat of combustion is between 18,700 BTU/pound to 18,900 BTU/pound as measured by ASTM D-240. Further, the use of hydrocarbon fluids from which aromatics have been removed or reduced may also increase hydrogen content of the formulated fuel.

In addition, isoparaffinic blend stocks may help to raise the gravimetric net heat of combustion when included in the blend, as such blend stocks' net heat of combustion is greater than aromatics or naphthenics that are characterized by the same carbon number. Normal paraffin blend stock may also raise the net heat of combustion.

Density is an important parameter of the fuel as it affects the weight of the fuel that can be lifted by the vehicle and the sortie range. Within the framework of the desired distillation curve, hydrocarbon fluids may be chosen to alter the density of the final blend. For example, naphthenic based fluids will tend to raise the final density while isoparaffinic fluids tend to reduce the density of the final product. Materials that contain a significant amount of naphthenes and are at the high end of the distillation curve relative to a fuel specification such as JP-5, such as HYDROSEALS®, can be used to increase the density of the blended product. In certain embodiments of the present disclosure, the density at 15° C. is between 0.77 and 0.82, between 0.799-0.815, between 0.81 to 0.850, and between 0.77 to 0.80, as measured by D-1298.

Accordingly, one or more embodiments utilize isoparaffin hydrocarbon fluids as at least one of the two or more hydrocarbon fluids. In one or more embodiments, the fuel may include a first hydrocarbon fluid having a density greater than 0.8 g/ml and a second hydrocarbon fluid having a density less than 0.8 g/ml, for example. The formulated fuels may have a weight that is about 5%, or 7% or 9% less than the weight of the JP-5 fuel, for example.

Hydrogen content of the fuel has a significant effect on the performance of the fuel. Generally, the higher the hydrogen content, the lower the molecular weight of the combustion products and the higher the exhaust velocity. The motion impulse of a jet engine is equal to the fluid mass multiplied by the velocity of the exhaust gas. However, as the vehicle moves forward, the fluid moves toward it creating an opposing ram drag. Thus, the net thrust is proportional to the difference between the vehicle velocity and the exhaust velocity. This implies that the vehicle cannot accelerate past its exhaust velocity. One way of maximizing this velocity difference is to reduce the molecular weight of the exhaust gases. Theoretically, this additional exhaust velocity would facilitate a greater top speed for the aircraft.

In certain embodiments of the present disclosure, the hydrogen content of the formulated fuel is controlled by increasing the ratio of hydrogen to carbon atoms of the molecules of the hydrocarbon fluid blend stocks. For instance, reducing rings and branching and increasing the degree of hydrogen saturation of hydrocarbon molecules increases the hydrogen:carbon atom ratio, thereby increasing hydrogen content of the fuel. Removing or reducing aromatics in the hydrocarbon fluid blend stocks may result in a significant increase in hydrogen content. Hydrogen content in certain embodiments of jet fuel of the present disclosure are greater than 13 wt %, from 14.25-15.5 wt %, from 14-14.8 wt %, less than 15.3 wt %, and between 14.8 and 15.5 wt % as measured by ASTM D-3343, compared to the JP-5 specification of 13.4%.

Typically, the hydrocarbon fluids used in the blended formulated fuel have very low sulfur concentration. Sulfur adversely affects fuel performance in a number of ways, including reducing the net heat of combustion and increasing fouling. Therefore in some embodiments, the formulated fuels include significantly reduced sulfur contents compared to conventional jet fuels. For example, the formulated fuels may include less than 30 ppm or less than 5 ppm sulfur. In other embodiments, the formulated fuels contain less than 3 ppm sulfur or less than 1 ppm sulfur.

Due to the significant absence of olefins and aromatics from the formulated fuel, the formulated fuels exhibit improved thermal stability over a traditionally manufactured jet fuel. Engines utilized in the vehicles described herein may utilize jet fuel in order to cool engine parts. These parts periodically foul, in large part due to aromatics and/or olefins present in the fuel. Accordingly, the formulated fuels provide a fuel that may allow a reduced maintenance schedule to be realized without any loss in performance.

Further, the absence of olefins and aromatics will result in improved smoke point performance of the fuels. In ASTM D-1322, a reference fuel containing 25% (volume) toluene and 75% (volume) isooctane is expected to have a smoke point of 20.2 mm. In certain embodiments of the present disclosure, the smoke point of the formulated fuel exceeds 25 mm and in other formulations is 30 mm or more. As formulated, the jet fuels described herein are characterized by no measurable aromatics by ASTM D-1319. Thus, use of these fuels is expected to result in cleaner engine operation, elimination of soot and particulate emissions, and the elimination of a telltale trail behind military jets.

The formulated fuels of the present disclosure overcome problems of certain traditional jet fuels' performance by blending existing hydrocarbon fluids to produce a fuel at least equal in properties, if not superior to, traditionally manufactured jet fuels. Further, the formulated fuels of the present disclosure can be tailored to provide properties such as density, hydrogen content, and heat of combustion.

In other embodiments of the present disclosure, jet turbine fuels are formed from a single hydrocarbon fluid. In these embodiments, the single hydrocarbon fluid is hydrotreated to remove sulfur and mercaptans, as well as to saturate aromatics that are present in the hydrocarbon fluid.

It is further contemplated that the formulated fuel may contain various additives, such as dyes, antioxidants, metal deactivators, and combinations thereof, for example.

Examples

Samples of various formulated fuels were analyzed by D-86, density, aniline point, cloud point, sulfur content, and aromatics content by FIA. The distillation curve and density were used to calculate hydrogen content by ASTM D-3343. The distillation curve, density, aniline point, sulfur content, and aromatics content were used to calculate the net heat of combustion by ASTM D-4529. The density was measured at 15° C., as required by ASTM D-4529, which is an estimation of the net heat of combustion. Subsequent density measurements made on formulated fuels were done on the same basis. The latter was used to calculate the net heat of combustion.

The materials analyzed for use in the formulated fuels were SPIRDANE® D-40, SPIRDANE® D-60, KETRUL® D-70, KETRUL® D-80, HYDROSEAL® G 232 H, ISANE IP®175, and ISANE IP®185. The distillation curves for these components are shown in FIG. 1. None of the individual components exhibit a full range distillation curve and could not be used “as is,” i.e. without formulation. The components were either high boiling, as was the G 232H, low boiling, like the D-60, or characterized by a narrower boiling range, like the D-80. However, this combination of attributes for the blend components allows flexibility in blending as the front, middle, and back end of the distillation curve for the fuel can be tailored to match a desired specification. Alternatively, various characteristics of the fuel relating to the distillation curve or other properties can be optimized through the appropriate selection of components for blending.

The density measurements for all components excluding the ISANE IP® materials were close to that of the traditionally manufactured jet fuel. ISANE IP® materials were characterized by a lower density than that of the traditionally manufactured jet fuel. The net heats of combustion and hydrogen content for those components, including ISANE IP® materials, were comparable to the traditionally manufactured jet fuel.

Once component data was compiled, the formulated fuels were made. A number of prototype blends were made to gauge how the components affected each other in combination. Three prototypes were made and designated proto-6, proto-7, and proto-8. Proto-6 was designed to have a traditional kerosene distillation curve. Proto-7 and proto-8 were designed to be lower boiling and higher boiling than standard fuel, on average, respectively. The latter two were made to determine what range of density and other properties would be achievable with the current blend components, such as SPIRDANE®, KETRUL®, and HYDROSEAL® based materials if the limits of the distillation curve were pushed. Blend formulations for the prototypes are shown in Table 3.

TABLE 3
Blend
Formulation	D-60 (vol %)	D-70 (vol %)	D-80 (vol %)	G232H (vol %)
Proto-6	70	5	0	25
Proto-7	90	5	0	5
Proto-8	45	0	10	45

The distillation curve data for proto-6, proto-7, and proto-8 is shown in FIG. 2. With specifications only at the 10% and the endpoint, there is wide latitude in the distillation curve that will meet the JP-5 specification. All three prototypes met this specification. Proto-8, designed to be high boiling on average, had a 10% point at 410° F. All three had end points below the (300° C.) JP-5 maximum. Proto-7 was significantly below it at 465° F. (240° C.), by design.

A high concentration of the light D-60 component reflected in the position of the proto-7 distillation curve below all others tested. Similarly, the high concentration of the heavy component G232H raised the proto-8 distillation curve above all the others.

Cloud point data for all formulations was below the freeze specification of (−46° C.) JP-5 and −58° C. JP-4 indicating that all have an acceptable freeze point. The sulfur content was measured by wavelength dispersive x-ray fluorescence, as noted earlier. Prototype formulations were at the limit of detection for that method with measurements at 0.5-0.6 ppm. The density measurements were within the JP-4 and JP-5 specifications. The density measurements are compared in FIG. 3.

ISANE IP® 175 and 185 are characterized by densities significantly lower than the traditionally manufactured jet fuel, but have flash points that are at or above that of the JP-5 specification. The density of each of these was below 0.77 g/ml, a significant reduction relative to other blend components and the traditionally manufactured jet fuel. Additionally, the hydrogen content was measured between 15.1 and 15.2. This is in agreement with the theoretical value of 14.9-15.3% for a fully saturated sample with no naphthenic rings in the C₁₂ to C₁₈ range and as reflected by typical values reported on the certificate of analysis for these materials.

The distillation curve data is shown in FIG. 4 for certain hydrocarbon fluids. The new materials are very narrow cuts with end points below 400° F. (204° C.). This necessitates the use of a middle and heavy cut in order to create jet fuel formulation. Additionally, the front end of the distillation curve was very clean indicating that few very light, low flash point compounds were present making these ideal blend components for the light portion of the formulation. The prototype blends formulated with the new components were designated proto-9 through proto-12. The composition of these blends is shown in Table 4.

TABLE 4
					ISANE	ISANE
Blend	D-60	D-70	D-80	G232H	IP 175	IP 185
Formulation	(vol %)	(vol %)	(vol %)	(vol %)	(vol %)	(vol %)
Proto-6	70	5	0	25	0	0
Proto-7	90	5	0	5	0	0
Proto-8	45	0	10	45	0	0
Proto-9	0	10	0	30	0	60
Proto-10	0	0	15	20	0	65
Proto-11	0	12.5	0	12.5	75	0
Proto-12	0	15	0	20	0	65

The distillation curves corresponding to the new formulations are shown in FIG. 5. Proto-9 matched the Proto-6 distillation curve closely. Proto-11 was designed to be a low density fuel, as shown by the rather high concentration of ISANE IP®175 in its formulation. Proto-10 and Proto-12 were formulated to contain a greater proportion of middle boiling compounds and examine the difference between the contributions of D-70 versus D-80 to the distillation curve. As shown, the difference was minimal for the quantities used.

The immediate effect of the presence of replacing the lower boiling components with isoparaffins can be seen on the density measurement in FIG. 6. The low-density blend proto-11 was measured at 0.7744 g/ml. This formulation saves about 800 pounds on the internal fuel load of an F/A-18E fighter. Alternatively, the density can be maximized if desired as in Proto-8.

The hydrogen content for the prototypes is shown in FIG. 7. Replacing some of the compounds that are naphthenic in nature with the fully saturated isoparaffins resulted in a net increase in hydrogen content to nearly 14.9 for proto-9 and to 15 for the low-density formulation, proto-11. This was a significant increase over the 13.4% JP-5 specification.

The net heat of combustion for the prototypes is shown in FIG. 8.

In addition to the above proto-formulations, proto-20 was formulated. Proto-20, like proto-6 and proto-9 was designed to match within reasonable limits a normal distillation curve. FIG. 9 illustrates the distillation curves for all four formulations. However, proto-20 was also designed to provide an intermediate density, hydrogen content, and net heat of combustion between proto-6 and proto-9. Hence, Proto-20 has a density at 15° C. of 0.8001, a hydrogen content of 14.51 wt %, and a net heat of combustion of 18,736 BTU/lb.

Samples of proto-6 and proto-20 were measured according to ASTM-D1322 to determine the smoke point. The smoke point of proto-6 was 30 mm and that of proto-20 was 31 mm.

In another example, jet fuel was hydrotreated. Conditions of the hydrotreater were:

TABLE 4
Start of run inlet pressure      550 psig
Hydrogen circulation             1800 SCF per barrel
Liquid hourly space velocity     0.82 per hour
Hydrogen purity                  95%
Inlet temperature (start of run) 640° F.
Inlet temperature (end of run)   700° F.

The resulting jet turbine fuel had the following characteristics:

	TABLE 5
	Aromatics Vol. %	ASTM D 1319	17.2
	Smoke Point	ASTM D 1322	21.0
	Net Heat of Combustion (BTU/lb)	ASTM D 3338	18541
	API Gravity	ASTM D 4052	41.1
	Freeze Point (° C.)	ASTM D 56	−53
	Sulfur (wt %)	ASTM D 7039	<0.2 ppm
	Mercaptan (wt %)	UOP 163	<1 ppm
	Distillation 10%	D 86	382
	End Point (° F.)	D 86	490

While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof and the scope thereof is determined by the claims that follow.

Claims

1. A method of manufacturing a jet turbine fuel comprising combining at least two hydrocarbon fluids.

2. The method of claim 1 wherein the jet turbine fuel meets JP-5, JP-4, JP-8, Jet-A1, or Jet-A specifications.

3. The method of claim 1 wherein the hydrocarbon fluids have a specific gravity at 60° C. of between 0.760 and 0.850, as measured by ASTM D-1298.

4. The method of claim 3, wherein the hydrocarbon fluids have a specific gravity at 60° C. of between 0.790 and 0.81, as measured by ASTM D-1298.

5. The method of claim 1, wherein the hydrocarbon fluids have a sulfur concentration of less than 3 ppm as measured by ASTM D-5623.

6. The method of claim 1, wherein the hydrocarbon fluids have an aromatics content of less than 1% by volume, as measured by ASTM D-1319.

7. The method of claim 6, wherein the hydrocarbon fluids have an aromatics content of less than 0.1% by volume, as measured by ASTM D-1319.

8. The method of claim 1, wherein the hydrocarbon fluids have an olefins content of less than 0.1% by volume, as measured by ASTM D-1319.

9. The method of claim 1, wherein the hydrocarbon fluids have a hydrogen content of from of greater than 13 wt. %, as measured by ASTM D-3343.

10. The method of claim 1, wherein the hydrocarbon fluids have a flash point of between 90 and 225° F., as measured by ASTM D-93.

11. The method of claim 1, wherein the jet turbine fuel has a hydrogen content of from between 14.25 to 15.5 wt. %, as measured by ASTM D-3343.

12. The method of claim 11, wherein the jet turbine fuel has a hydrogen content of from between 14.8 to 15.5 wt. %, as measured by ASTM D-3343.

13. The method of claim 1, wherein the jet turbine fuel has a net heat of combustion greater than 18,300 BTU/pound, as measured by ASTM D-240.

14. The method of claim 13, wherein the jet turbine fuel has a net heat of combustion between 18,500 and 19,000 BTU/pound, as measured by ASTM D-240.

15. The method of claim 1, wherein the density of the jet turbine fuel at 15° C. is from 0.750-0.850, as measured by ASTM D-1298.

16. The method of claim 15, wherein the density of the jet turbine fuel at 15° C. is from 0.750-0.850, as measured by ASTM D-1298.

17. The method of claim 1, wherein at least one of the hydrocarbon fluids comprises an isoparrafin.

18. The method of claim 1, wherein at least one of the hydrocarbon fluids comprises a normal paraffin.

19. The method of claim 1, wherein the jet fuel has an aromatics content of less than 0.1% by volume, as measured by ASTM D1319.

20. The method of claim 1, wherein none of the hydrocarbon fluids meet the JP-5 specification.

21. A jet turbine fuel comprising a hydrocarbon fluid, wherein the jet turbine fuel has a sulfur content of less than 1 ppm as measured by ASTM D-7039.

22. The jet turbine fuel of claim 21, wherein the jet turbine fuel has a sulfur content of less than 0.5 ppm as measured by ASTM D-7039.

23. The jet turbine fuel of claim 21, wherein the jet turbine fuel has a smoke point of greater than 20 mm as measured by ASTM D-1322.

24. The jet turbine fuel of claim 23, wherein the jet turbine fuel has a smoke point of greater than 30 ppm as measured by ASTM D-1322.