Patent Description:
The freeze point of a jet fuel composition is an important factor in determining whether it is suitable for operation under low temperature conditions.

<CIT> discloses a diesel fuel blend having enhanced cold properties. The diesel fuel blend comprises a blend of a renewable fuel component and a mineral middle distillate fuel component in which the renewable fuel component and mineral middle distillate fuel component are present in a ratio of amounts by volume of from <NUM>:<NUM> to <NUM>:<NUM> and the diesel fuel blend contains <NUM>-<NUM> wt% n-paraffins in the C14-C20 range and an amount of iso-paraffins in the C14-C20 range such that the ratio of the sum of wt% amounts of iso-paraffins in the C14-C20 range to the sum of wt% amounts of n-paraffins in the C14- C20 range is less than <NUM>. This document does not disclose jet fuel compositions.

<CIT> discloses a fuel composition prepared by blending petroleum derived kerosene base fuels and Fischer-Tropsch derived kerosene base fuels. The Fischer-Tropsch derived kerosene base fuel has boiling points within the range <NUM> to <NUM>, a density from <NUM> to <NUM>/m<NUM> at <NUM> and consists of 90wt% or more of paraffinic components. It contains normal and iso-paraffins in a weight ratio of greater than <NUM>:<NUM>. The purpose of addition of this Fischer-Tropsch derived kerosene base fuel, in an amount of <NUM> to 81vol% in the fuel composition, is to reduce the freeze point of the fuel composition below that of the petroleum derived kerosene fuel.

<CIT> discloses a fuel composition comprising a petroleum derived jet fuel component and a renewable jet fuel component, wherein the fuel composition has a freezing point of -<NUM> or below and a cetane number more than <NUM>. The renewable jet fuel component is a hydrotreated middle distillate having a distillation range from <NUM> to <NUM>. The petroleum derived jet fuel component has a freezing point between -<NUM> and -<NUM> and the difference between the freezing point of the renewable jet fuel component and the freezing point of the petroleum derived jet fuel component is less than <NUM>. The renewable jet fuel component has an iso-paraffin content of more than 70wt%, more than 70wt% of C15 to C18 paraffins, less than 20wt% of paraffins smaller than C15 paraffins, less than 10wt% of paraffins larger than C18 paraffins.

<CIT> describes a method of making a jet fuel composition comprising a mineral-based kero/jet-type distillate component having an initial boiling point of at least <NUM>° C and a deoxygenated and dewaxed renewable component derived from triglycerides and/or fatty acids having an iso-paraffin to normal paraffin ratio from <NUM>:<NUM> to <NUM>:<NUM> and an aromatics content less than about <NUM> vol %. The jet fuel composition comprises from 3vol% to 25vol% of the renewable component.

<CIT> discloses compositions that include at least <NUM> wt% n-paraffins which may be suitable for use as a diesel fuel, aviation fuel, jet fuel blendstock, a blendstock to reduce the cloud point of a diesel fuel. The composition includes at least 98wt% C7-C12 n-paraffins, where at least 10wt% of the composition includes n-decane, at least 20wt% of the composition includes n-dodecane, and at least 75wt% of the composition includes even carbon number paraffins.

<CIT> discloses another blend of a petroleum-derived jet fuel and a renewable jet fuel.

However, cold properties of a jet fuel composition comprising a petroleum derived jet fuel component and more particularly the freezing point is not improved by addition of a renewable component for any petroleum derived jet fuel component with respect to the calculated freezing point obtained by a linear relation.

The present invention relates to jet fuel compositions, in particular jet fuel compositions having improved cold properties, and more particularly improved freezing point with respect to theoretical linear behavior, which are mixtures of jet fuel from petroleum origin and renewable component.

An improvement of cold properties and more specifically of the freezing point of the fuel composition of the invention, is obtained by mixing a jet fuel from petroleum origin with a particular normal paraffins content to <NUM> to 50vol% of a renewable component consisting of hydroprocessed esters and fatty acids.

A petroleum derived jet fuel component consists predominantly of refined hydrocarbons and trace levels of materials that are not hydrocarbons including oxygenates, organosulfur and nitrogenous compound. The refined hydrocarbons are derived from conventional sources including crude oil, natural gas liquid condensates, heavy oil, shale oil and oil sands.

Hydroprocessed esters and fatty acids consist predominantly of mono-, di- and triglycerides, free fatty acids and fatty acid esters, which have been hydroprocessed to remove essentially oxygen.

The invention relates to a jet fuel according to claim <NUM>.

The jet fuel composition of the invention has a freezing point below a theoretical freezing point calculated from a linear relation, and optionally below the freezing point of each component. This theoretical freezing point is obtained in a usual way by pondering the freezing point of each compound by its content and addition of the results.

In particular, the petroleum derived jet fuel component may have a content of paraffins lower than C9 less than 10wt%, preferably less than 5wt% and a content of paraffins higher than C12 less than 20wt% preferably less than <NUM>%wt. The content of paraffins lower than C9 may be from <NUM> to <NUM> or 10wt%, or from <NUM> to <NUM> or 10wt%. The content of paraffins higher than C12 may be from <NUM> to <NUM> or <NUM> wt% or from <NUM> to <NUM> or 20wt% or within any of these limits.

In general, the petroleum derived jet fuel component may have a total content of paraffins from <NUM> to 55wt %, preferably from <NUM> to 50wt%.

In general, the petroleum derived jet fuel component may preferably be a petroleum derived jet fuel that complies with the requirements for jet fuels as specified in the following standards : DefStan <NUM>-<NUM> Issue <NUM>, ASTM D1655 January <NUM>. In particular, this petroleum derived jet fuel component may comply with the requirements for a Jet A1 or a Jet A.

In general, the petroleum derived jet fuel component may have a freezing point of -<NUM> or below.

In one embodiment, the content of renewable component in the jet fuel composition may be from <NUM> to 50vol% or from <NUM> to 50vol% or within any of these limits.

In general, the renewable component may include, or consist of, hydroprocessed synthesized paraffinic kerosine wholly derived from paraffins derived from hydrogenation and deoxygenation of fatty acid esters and free fatty acids and subsequent processing of the product including hydrocracking, or hydroisomerization, or isomerization, or fraction, or a combination thereof, and may include other conventional refinery processes. In other words, the renewable component is produced from hydroprocessed esters and fatty acids. Advantageously, the renewable component may comply with the requirements of synthesized paraffinic kerosine specified in Annex <NUM> of ASTM D7566 March <NUM>.

The renewable component may be produced from natural occurring oil(s), in particular from the above mentioned treatments of such natural occurring oil(s).

A natural occurring oil is defined as an oil of biomass origin, and do not contain or consist of any mineral oil. In the description "natural occurring oil(s)" designates indifferently oil, fat and their mixtures.

Said natural occurring oil(s) may contain one or several oils chosen among vegetable oil, animal fat, preferentially inedible highly saturated oils, waste oils, by-products of the refining of vegetable oil(s) or of animal oil(s) containing free fatty acids, tall oils, and oil produced by bacteria, yeast, algae, prokaryotes or eukaryotes.

Suitable vegetable oils are for example palm oil, palm kernels oil, soy oils, soybean oil, rapeseed (colza or canola) oil, sunflower oil, linseed oil, rice bran oil, maize (corn) oil, olive oil, castor oil, sesame oil, pine oil, peanut oil, castor oil, mustard oil, carinata oil, palm kernel oil, hempseed oil, coconut oil, babasu oil, cottonseed oil, linola oil, jatropha oil.

Animal fats include tallow, lard, grease (yellow and brown grease), fish oil/fat, butterfat, milk fats.

By-products of the refining of vegetable oils or animal oils are by-products containing free fatty acids that are removed from the crude fats and oils by neutralisation or vacuum or steam distillation. Typical example is PFAD (palm free acid distillate).

Waste oils include waste cooking oils (waste food oil) and oils recovered from residual water, such as trap and drain greases/oils, gutter oils, sewage oils, for example from water purification plants, and waste fat from the food industry.

Tall oils, including crude tall oils, distillate tall oils (DTO) and tall oil fatty acids (TOFA), preferably DTO and TOFA, can also be used in the present invention.

Tall oil, or otherwise known as tallol, is a liquid by-product of the Kraft process for processing wood, for isolating on the one hand the wood pulp useful in the papermaking industry, and on the other hand tall oil. Tall oil is essentially obtained when conifers are used in the Kraft process. After treating wood chips with sodium sulfide in aqueous solution, the tall oil isolated is alkaline. The latter is then acidified with sulfuric acid to produce crude tall oil.

The natural occurring oil(s) used in the present invention also include oils produced by microorganisms, either natural or genetically modified microorganisms, such as bacteria, yeast, algae, prokaryotes or eukaryotes. In particular such oils can be recovered by mechanical or chemical extraction well known methods. The renewable jet fuel component may have one or more of the following features :.

In combination or not with any of one or several of the above physical properties, the renewable component may have one or more of the following features :.

The jet fuel composition of the invention has a normal paraffins content of C9-C12 paraffins from <NUM> to 20wt% and a total normal paraffins content from <NUM> to 30wt%.

Advantageously, the jet fuel composition of the invention may comply with Jet A or Jet A1 requirements as defined in ASTM D7566 March <NUM> or into DefStan <NUM>-<NUM> Issue <NUM> which refers to ASTM D7566. In particular, the content of renewable component in the jet fuel composition may be chosen such that the jet fuel composition complies with these requirements.

According to a second aspect, the invention claims a method for producing a jet fuel composition, wherein the method is as defined in claim <NUM>.

The petroleum derived jet fuel component may be as previously described with respect to the jet fuel composition.

The renewable component may be as previously described with respect to the jet fuel composition.

Outside of the scope of the invention is the use of a petroleum derived jet fuel component having a content of C9-C12 normal paraffins from 17wt% to 30wt% for preparing a jet fuel composition from a mixture of a petroleum derived jet fuel component and a renewable component consisting of hydroprocessed esters and fatty acids, such jet fuel composition having a freezing point of -<NUM> or below, preferably of -<NUM> or below, said freezing point being lower than a theoretical freezing point calculated from a linear relation.

Outside of the scope of the invention is a method for obtaining a jet fuel composition from a mixture of a petroleum derived jet fuel component and a renewable component consisting of hydroprocessed esters and fatty acids, such jet fuel composition having a freezing point of -<NUM> or below, preferably of -<NUM> or below, said freezing point being lower than a theoretical freezing point calculated from a linear relation, wherein the renewable component is mixed in a content from <NUM> to 50vo% with a petroleum derived jet fuel component having a content of C9-C12 normal paraffins from 17wt% to 30wt%. The petroleum derived jet fuel component and the renewable component may each be as previously described with respect to the jet fuel composition.

The invention will be better understood with reference to the figures, which show exemplary embodiments of the invention.

Several petroleum jet fuel components have been mixed with different renewable components.

Table <NUM> resumes the physical properties and composition of the petroleum jet fuel components and table <NUM> resumes the physical properties and composition of the renewable components.

The compositions were determined by a GCxGC method.

Petroleum jet fuel components A and B have n-C9-C12 contents according to the invention. This is not the case of jet fuel components C, D which are used to prepare comparative examples.

The freezing points have been measured using two standard methods.

The first method is a manual one which is the usual reference method and corresponds to ASTM D2386-<NUM>.

The second method is an automatic one and corresponds to ASTM D7153-15e1. It has been implemented with a PAC ISL apparatus.

The reproducibility "R" of these freezing point measurement methods are the following :.

All the jet fuel compositions comprising the petroleum jet component A show significantly improved cold properties with respect to the calculated freezing point, as also shown for some renewable component on <FIG>. By "significantly improved" we mean that the difference between the measured freezing point and the calculated freezing point is equal or higher than the reproducibility of the freezing point measurement method.

From <FIG>, we can expect an improvement of cold properties with respect to the linear calculations, with incorporation of <NUM> to <NUM> vol% of renewable jet component. Similar or better cold properties as the petroleum jet fuel component will be obtained.

The results show that improvement of cold properties is obtained even with renewable component having a high freezing point (-<NUM>). For some renewable jet components, the freezing point of the jet fuel composition is better than the freezing point of the petroleum jet component, or similar, but always within the specifications of jet fuels.

Similar results are obtained with jet fuel compositions comprising the petroleum jet component B, as more clearly seen on <FIG>.

Without wishing to be bound by a theory, the observed improvements may be due to the content of nC9-C12 of the jet fuel component.

Jet fuel compositions comprising a petroleum jet component which do not have from 17wt% to 30wt% of n-C9-C12 all have a freezing point which is not significantly better that the freezing point calculated from the linear relation. By "not significantly better" we mean that the difference between the measured freezing point and the calculated freezing point is less than the reproducibility of the freezing point measurement method. This can be clearly seen on the graph of <FIG>, which shows the measured (with ASTM D2386-<NUM>) and calculated freezing point of compositions comprising jet component C.

Only the fuel compositions including a renewable component with a very low freezing point (-<NUM>) have a freezing point below the one of the petroleum jet component, but always not significantly better that the calculated freezing point.

These results show that the cold properties of jet fuel composition comprising such petroleum jet component are not significantly improved despite the high iso-paraffins content of the renewable component.

Claim 1:
Jet fuel composition consisting of a petroleum derived jet fuel component and a renewable component consisting of hydroprocessed esters and fatty acids, wherein
- the jet fuel composition contains <NUM> to 50vol% of the renewable component and has a freezing point of -<NUM> or below, preferably of -<NUM> and below,
- the renewable component has a freezing point below - <NUM>, and
- the petroleum derived jet fuel component has a freezing point of -<NUM> or below and a content of C9-C12 normal paraffins from 17wt% to 25wt%,
and wherein
- the freezing point of the jet fuel composition is lower than a theoretical freezing point calculated from a linear relation, this theoretical freezing point being obtained by pondering the freezing point of each component by its volume content and addition of the results,
- the jet fuel composition has a normal paraffins content of C9-C12 paraffins from <NUM> to 20wt% and a total normal paraffins content from <NUM> to 30wt%,
the above-mentioned freezing points of the jet fuel composition and of its components being determined using a single and same method chosen from ASTM D2386-<NUM> or ASTM D7153-15e1.