The C6-C16 or C8-C16 aromatic base according to the invention can have one or more of the following characteristics:

- at least 60% by mass o C8-C16 aromatic compounds, in particular monoaromatic compounds, said aromatic compounds comprising at least 50% by mass o benzene substituted by at least n C2-C5 alkyl, n being an integer from 1 to 3,
- from 8% by mass to 15% by mass of naphthenes,
- from 5% by mass to 15% by mass of isoparaffins,
- less than 5% by mass of n-paraffins,
- a density of 855 to 870 kg/m³measured in accordance with standard ASTM D1298-12b (2017).

It should be noted that said aromatic compounds present in a proportion of at least 60% by mass comprise benzene substituted by at least n C2-C5 alkyl. These aromatic compounds can thus comprise a mixture of benzene molecules substituted by at least n C2-C5 alkyl and optionally benzene molecules substituted by at least n C2-C5 alkyl and by m methyl, m being an integer from 1 to 3.

In particular, the production of the paraffinic and aromatic bases according to the invention can be implemented using different renewable sources, and in particular by separate methods.

Mixture According to the Invention

Advantageously, the jet-fuel composition according to the invention can be in accordance with the Jet A or JET A1 requirements as defined in standard ASTM D7566:2021 of July 2021 corresponding substantially to DefStan 91-091 Issue 12, or in DefStan 91-091 Issue 11, which refers to standard ASTM D7566:21. In particular, the proportions of paraffinic base a) and aromatic base b) in the jet-fuel composition according to the invention can be selected so that the jet-fuel composition according to the invention is in accordance with these requirements.

In an advantageous embodiment, the at least one paraffinic base a) and the at least one aromatic base b) come from separate treatments of renewable feedstocks (from distinct methods), in particular of distinct renewable feedstocks.

In a preferred embodiment, the jet-fuel composition according to the invention consists of paraffinic a) and aromatic b) bases coming from renewable feedstocks. In particular, the jet-fuel composition according to the invention is free from components of petroleum origin.

DESCRIPTION OF FIGURES

FIG. 1: Distribution of the hydrocarbons in the mixture according to example 1.

FIG. 2: curve of change in the smoke point as a function of the aromatic content of cuts 150-230° C.

The following examples illustrate the invention without limiting the scope thereof.

EXAMPLES
Example 1

A mixture according to the invention is prepared. The mixture contains 90% by mass of HEFA conforming to the paraffinic base a) according to the invention and 10% by mass of the C8-C16 aromatic base b).

Other additives can be added to the composition so that the jet-fuel composition according to the invention is in accordance with the requirements of standard ASTM D7566:21.

Adding the aromatic base b) makes it possible to obtain a composition wherein the C8-C12 content is increased, as shown on FIG. 1.

Compared with a fossil jet fuel, the composition according to the invention has a small polycyclic aromatic hydrocarbon content. Thus, the quantity of monoaromatics hydrocarbons with respect to the total quantity of aromatic hydrocarbons is higher for the present composition than for fossil jet fuel. The composition is thus useful for reducing the polyaromatic hydrocarbon content of a fuel and increasing the proportion of monoaromatic hydrocarbons. Advantages are obtained in terms of improving the combustion with an improvement in the smoke point and a reduction in soot emissions.

Example 2—Effect on the Smoke Point

Kerosene cuts (150-230° C.) coming from various crudes of fossil origin were analysed in order to determine their aromatic compound content and the smoke point.

The smoke point was determined in accordance with standard ASTM D1322-19.

The aromatic compound content was determined in accordance with standard ASTM D1319-20A.

FIG. 2 shows the change in the smoke point as a function of the aromatics content of these kerosene cuts.

C1-C4 jet-fuel compositions according to the invention were prepared in the proportions set out in table 1. These compositions are mixtures of an SBK-HEFA (density of 760.9 kg/m³) with an aromatic base A1 (C1 composition) or with an aromatic base A2 (C2-C4 compositions).

The aromatic base A1 corresponds to a 140+° C. cut of a biofuel. The aromatic base A2 corresponds to a 135+° C. cut of a biofuel. These bases contain mainly compounds with a cut point of 150° C. and more.

The characteristics of the aromatic bases A1 and A2 are set out in tables 2 to 4. The density was determined in accordance with standard ASTM D1298-12b (2017).

The smoke point of the C1-C4 compositions was measured and is set out in table 1.

TABLE 1

C1
C2
C3
C4
SPK-HEFA

SPK-HEFA vol %
86.00
85.00
90.00
95.60
100.0

aromatic base vol %
14.00
15.00
10.00
4.40
0.00

% mass SPK-HEFA mass %
84.34
83.34
88.82
95.00
100.00

aromatic base mass %
15.66
16.66
11.18
5.00
0.00

Smoke point (mm)
32.1
33.0
43.0
42.0
51.3

TABLE 2

Aromatic base A1
Aromatic base A2

Density

868 kg/m³
862 kg/m³

Composition

(% m)
(% vol)

(% m)
(% vol)

cuts
140-145°
C.
5.05
5.18
135-150°
C.
21.87
22.50

145-150°
C.
3.03
3.10
150+°
C.
78.13
77.50

150+°
C.
91.92
91.72

TABLE 3

Composition of base A1 by analysis in accordance

with standard NF EN ISO 22854

Aromatic base A1

(% m)
C1-C7
C8
C9
C10
C11
C12+
Total

Naphthenes
0.00
0.06
1.89
1.48
0.21
0.00
3.65

Isoparaffins
0.00
0.00
0.60
0.87
0.37
0.00
1.85

N-paraffins
0.00
0.00
0.07
0.02
0.00
0.00
0.09

Cyclo-olefins
0.00
0.02
0.40
0.44
0.12
0.00
0.98

Olefins
0.00
0.00
0.01
0.00
0.00
0.00
0.01

Aromatics
0.00
9.51
78.10
0.00
0.00
0.00

Compounds with

5.05 ⁽¹⁾

a cut point of

200+° C.

Polynaphthenes

0.76