WO2019002679A1

WO2019002679A1 - Low aromatic fuel composition comprising renewable diesel

Info

Publication number: WO2019002679A1
Application number: PCT/FI2018/050494
Authority: WO
Inventors: Seppo Mikkonen; Jukka Nuottimäki
Original assignee: Neste Oyj
Priority date: 2017-06-29
Filing date: 2018-06-26
Publication date: 2019-01-03
Also published as: FI20175619A; FI12194U1; FI20175619A1

Abstract

A low aromatic fuel composition is disclosed comprising from 33 to 80 vol % renewable paraffinic diesel component and from 5 to 60 vol % fossil paraffinic diesel component and/or from 5 to 60 vol % GTL based diesel component, wherein, the low aromatic fuel composition comprises more than 60 wt % paraffins, less than 40 wt % naphthenes and less than 0,5 wt % aromatics.

Description

LOW AROMATIC FUEL COMPOSITION COMPRISING RENEWABLE DIESEL

FIELD OF THE INVENTION

The present disclosure relates to a low aromatic fuel composition having enhanced properties, a method for producing a low aromatic fuel composition and to use of a renewable paraffinic diesel component.

BACKGROUND

There are different standards for physical properties of fuels which need to be fulfilled depending on the area where the fuel is to be sold. EN 15940 is a standard published by the European Committee for Standardization describing the physical properties that paraffinic diesel fuel from synthesis or hydrotreatment must meet if it is to be sold in the European Union and several other European countries.

Low temperature properties of a fuel composition are an important property for fuels which are used in low temperature environments. The most important properties of fuels relating to their cold temperature operability are cloud point, pour point, and cold filter plugging point. As a middle distillate fuel is cooled, it will reach its cloud point. This is the temperature at which paraffin wax falls out of solution and starts to form wax crystals in the fuel. The storage temperature of a fuel is recommended to be higher than its cloud point. Another important property of a middle distillate fuel is its cold filter plugging point, which is the lowest temperature where the fuel is filterable and can be used in vehicles without problems.

Cetane number of a fuel composition needs to be on a sufficient level to allow the proper functioning of a diesel motor.

US2008216390A discloses a biodiesel fuel mixture having a cetane number of >40, comprising a) from 1 to 100 percent by weight of biodiesel, b) from 0 to 98.9 percent by weight of diesel oil of fossil origin, c) from 0.1 to 20 percent by weight of polyoxyalkylene dialkyl ether of the formula RO(CH₂0)nR in which R is an alkyl group having from 1 to 10 carbon atoms and n=from 2 to 10, and d) from 0 to 5 percent by weight of further additives. Biodiesel consists generally of fatty acid esters of the general formula R1-COOR2 in which Ri is a substantially linear saturated or unsaturated aliphatic radical having from 5 to 23 carbon atoms and R₂ is a linear or branched, saturated or unsaturated aliphatic radical having from 1 to 12 carbon atoms. SUMMARY OF THE INVENTION

An object on the present invention is to provide a low aromatic fuel composition comprising at least two of the following components: 33 to 80 vol % renewable paraffinic diesel component, from 5 to 60 vol % fossil paraffinic diesel component and/or from 5 to 60 vol % GTL based diesel component, wherein the low aromatic fuel composition comprises more than 60 wt % paraffins, less than 40 wt % naphthenes and less than 0,5 wt % aromatics based on the total amount of the low aromatic fuel composition.

Another object of the present invention is to provide a method for producing a low aromatic fuel composition, the method comprising mixing at least two of the following components: renewable paraffinic diesel component, fossil paraffinic diesel component and/or GTL based diesel component wherein the amount of renewable paraffinic diesel component is 33 to 80 vol %, the amount of fossil paraffinic diesel component is from 5 to 60 vol % and/or the amount of GTL based diesel component is from 5 to 60 vol % and the total aromatics content of the low aromatic fuel composition is less than 0,5 wt-% to provide a low aromatic diesel component. Yet another object of the present invention is the use of a renewable paraffinic diesel component for improving the properties of a low aromatic fuel composition comprising fossil paraffinic diesel component and/or GTL based diesel component wherein the amount of fossil paraffinic diesel component is from 5 to 60 vol % and the amount of GTL based diesel component is from 5 to 60 vol %, based on the total amount of the low aromatic fuel composition.

The objects are achieved by a low aromatic fuel composition and a method for producing thereof as well as the use of a renewable paraffinic diesel component, which are characterized by what is stated in the independent claims. Preferred embodiments of the invention are disclosed in the dependent claims.

DETAILED DESCRIPTION OF EMBODIMENTS

The following embodiments are exemplary. Although the specification may refer to "an", "one", or "some" embodiment(s) in several locations, this does not necessarily mean that each such reference is to the same embodiment(s), or that the feature only applies to a single embodiment. Single features of different embodiments may also be combined to provide other embodiments. Furthermore, words "comprising", "containing" and "including" should be understood as not limiting the described embodiments to consist of only those features that have been mentioned and such embodiments may contain also features/structures that have not been specifically mentioned.

The present invention provides a low aromatic fuel composition comprising at least two of the following components: from 33 to 80 vol % renewable paraffinic diesel component and from 5 to 60 vol % fossil paraffinic diesel component and/or from 5 to 60 vol % GTL based diesel component. The low aromatic fuel composition according to the present invention comprises more than 60 wt % paraffins, less than 40 wt % naphthenes and less than 0,5 wt % aromatics based on the total amount of the low aromatic fuel composition. Throughout the present disclosure, "vol %" refers to percentage based on the total volume of the low aromatic fuel composition and "wt %" refers to percentage based on the total weight of the low aromatic fuel composition. The low aromatic fuel composition of the present invention fulfills the requirements of EN 15940.

The present invention also provides a method for producing a fuel composition, the method comprising mixing the components: renewable paraffinic diesel component with fossil paraffinic diesel component and/or GTL based diesel component wherein the amount of renewable paraffinic diesel component is 33 to 80 vol %, fossil paraffinic diesel component is from 5 to 60 vol % and/or GTL based diesel component is from 5 to 60 vol % and the total aromatics content of the low aromatic fuel composition is less than 0,5 wt-%. The present invention also discloses use of a renewable paraffinic diesel component for improving the properties of a low aromatic fuel composition comprising renewable paraffinic diesel component, fossil paraffinic diesel component and/or GTL based diesel component. Usually when fuel components are blended it is not possible to obtain wanted good properties without deteriorating other properties. It has now been noticed that properties of a low aromatic fuel composition deteriorate less when there is renewable paraffinic diesel component present. Thus, it is possible to provide a low aromatic fuel composition with good low temperature properties and sufficient cetane number. The different properties of the low aromatic fuel composition can be varied by the amounts of different components in the low aromatic fuel composition.

The low aromatic fuel composition of the present invention comprises a renewable paraffinic diesel component having narrow carbon chain length (C_n) distribution as well as a fossil paraffinic diesel component including cycloparaffins (naphthenes) and/or a GTL (gas to liquid) based diesel component which is paraffinic diesel component having wide carbon chain length (C_n) distribution.

The renewable paraffinic diesel component herein refers to a diesel fuel component produced typically from vegetable oil and/or animal fats. Palm oil, rapeseed oil and/or waste fat from the food industry may be used as a raw material for the production of the renewable paraffinic component. Other examples of possible raw materials include waste fats from the food industry, biogas, algae oil, jatropha oil, soybean oil and/or microbial oil. Examples of possible waste fats from the food industry include cooking oil, animal fat and/or fish fat.

In an embodiment, the renewable paraffinic diesel component is produced by means of a hydrotreatment process. Hydrotreatment involves various reactions where molecular hydrogen reacts with other components, or the components undergo molecular conversions in the presence of molecular hydrogen and a solid catalyst. The reactions include, but are not limited to, hydrogenation, hydrodeoxygenation, hydrodesulfurization, hydrodenitrification, hydrodemetallization, hydrocracking, and isomerization. The renewable paraffinic diesel component may have different distillation ranges which provide the desired properties to the component, depending on the intended use.

Renewable paraffinic diesel component having narrow carbon chain length distribution typically has majority of the paraffins in the carbon chain lengths between C14 and C18. The amount of from C14 to C18 paraffins in the component is typically more than 85 wt % or more than 90 wt %. The amount of C13 paraffins or smaller is typically than 15 wt %, less than 10 wt % or less than 7 wt % and the amount of C19 paraffins or larger is typically less than 10 wt %, less than 5 wt %, less than 3 wt %. The amount of aromatics is typically less than 0,1 wt %. The amount of naphthenes is typically less than 2 wt %. As used herein the "fossil paraffinic diesel component" refers to middle distillate component comprising mainly non-aromatic hydrocarbons obtainable from fossil sources. Fossil paraffinic diesel component typically includes n-paraffins, i-paraffins and cycloparaffins (also called naphthenes), and it may be obtained from conventional refinery by dearomatization of middle distillates. Cycloparaffins are cyclic saturated hydrocarbons whereas aromatics are cyclic hydrocarbons which comprise conjugated double bonds (or one or more benzene rings). Fossil paraffinic diesel component may comprise cycloparaffins for example up to 70 wt % of the component. Cycloparaffins have typically 5 or 6 carbons in their ring structure. The paraffinic hydrocarbons in a fossil paraffinic diesel component comprise typically for example from C8 to C21 or from Cll to C19 chain length hydrocarbons. The amount of aromatics is typically less than 0,5 %.

GTL (gas to liquid) based diesel component may be obtained by a GTL process. A gas to liquids (GTL) process is a refinery process that enables converting natural gas or other gaseous hydrocarbons into longer-chain, typically paraffinic hydrocarbons, such as gasoline or diesel fuel. Methane-rich gases may be converted into liquid synthetic fuels either via direct conversion or via syngas as an intermediate. GTL based diesel component has typically wide carbon chain length distribution, such as from C9 to CI 7, or from C8 to C21, or from C12 to C20. The amount of aromatics in GTL based diesel component is typically less than 0,5 wt %, or less than 0,1 wt %. Since all the fuel components used in the present invention contain only small amounts of aromatics, the present invention provides a low aromatic fuel composition which fulfills standard EN 15940. EN15940 defines that the amount of aromatics is less than 1,1 wt %. In an embodiment the present invention provides a low aromatic fuel composition comprising less than 0,3 wt % aromatics, preferably less than wt 0,2 % aromatics, more preferably less than 0,1 wt % aromatics. The present invention also provides a method for producing such fuel.

The amount of paraffins and naphthenes in the low aromatic fuel composition depend on the fuel components used. In an embodiment the low aromatic fuel composition according to the present invention comprises more than 75 wt % paraffins, or more than 85 wt % paraffins, or more than 90 wt % paraffins, or more than 95 wt % paraffins. A low aromatic fuel composition according to the present invention comprises less than 25 wt % naphthenes, less than 15 wt % naphthenes, less than 10 wt % naphthenes, less than 5 wt % naphthenes.

In another embodiment a low aromatic fuel composition according to the present invention comprises more than 85 wt % from C14 to C18 hydrocarbons and less than 15 wt % C13 or smaller hydrocarbons and C19 or larger hydrocarbons combined. Therefore the low aromatic fuel composition of the present invention comprises more C14 to C18 hydrocarbons than either fossil paraffinic diesel component or GTL based diesel component alone, or a mixture thereof. In an embodiment the low aromatic fuel composition according to the present invention comprises at least 10 vol % fossil paraffinic diesel component. In another embodiment the low aromatic fuel composition according to the present invention comprises less than 20 vol % GTL based diesel component.

In an embodiment the low aromatic fuel composition according to the present invention comprises 70 vol % to 80 vol % renewable paraffinic diesel component, 5 vol % to 15 vol % fossil paraffinic diesel component and 5 vol % to 15 vol % GTL based diesel component. In another embodiment the low aromatic fuel composition comprises 80 vol % renewable paraffinic diesel component, 10 vol % fossil paraffinic diesel component and 10 vol % GTL based diesel component. Surprisingly such fuel composition provided improved cetane number, CFPP and oxidation stability, which all were notably better than could be expected based on calculations.

In an embodiment the low aromatic fuel composition comprises from 40 vol % to 60 vol % renewable paraffinic diesel component and from 60 vol % to 40 % vol fossil paraffinic diesel component. The fuel composition according to this embodiment provided remarkable improvement of cold properties, exemplified by significant reduction of CFPP value, while cetane number and oxidation stability followed calculated trends. Hence, use of renewable paraffinic diesel component improved cold properties of the fossil paraffinic diesel component.

Cold filter plugging point (CFPP) is the lowest temperature, expressed in degrees Celsius (°C), at which a given volume of diesel type of fuel still passes through a standardized filtration device in a specified time when cooled under certain conditions. CFPP of a fuel is suitable for estimating the lowest temperature at which a fuel will give a trouble-free flow in certain fuel systems. In an embodiment the low aromatic fuel composition according to the present invention has CFPP less than -20 °C, preferably less than -25 °C, more preferably less than -30 °C.

Cetane number (CN) is an inverse function of a fuel's ignition delay, and the time period between the start of injection and the first identifiable pressure increase during combustion of the fuel. In a particular diesel engine, higher cetane fuels will have shorter ignition delay periods than lower cetane fuels. In an embodiment the low aromatic fuel composition according to the present invention has cetane number more than 58, preferably more than 65, preferably more than 70.

Oxidation stability measurement is used for estimation of the long term storage stability of diesel fuels. In an embodiment the low aromatic fuel composition according to the present invention has oxidation stability more than 60 min, preferably more than 65 min, preferably more than 70 min.

EXAMPLES Example 1. Fuel compositions

Six low aromatic fuel compositions containing different amounts of renewable paraffinic diesel component, fossil paraffinic diesel component and/or GTL based diesel component were prepared by mixing the diesel components. The contents of the low aromatic fuel compositions thus prepared are presented in Table 1.

Table 1. Fuel compositions tested

The amounts of different hydrocarbons in the blended fuel compositions were determined using GC X GC. Table 2 presents the amounts of aromatics, naphthenes and i- and n-paraffins in the fuel compositions.

Table 2. The amount of different hydrocarbons in the low aromatic fuel compositions.

Example 2. Properties of the low aromatic fuel compositions

The effect of the different components to the properties of blended fuel compositions tested. CFPP (Cold filter plugging point, EN116), cetane number (ASTMD6890) and oxidation stability (EN16091) were measured for pure diesel components as well as for the blended fuel compositions. Table 3 presents the properties of each diesel component as such.

Table 3. Properties of the pure diesel components

Table 4 shows the properties of the low aromatic fuel compositions comprising different amounts of each diesel component. Table 4 shows both the measured values as well as calculated values for different fuel compositions.

Table 4. Properties of the low aromatic fuel compositions.

The results show that all the measured values were poorer than calculated average values when there was 0 vol % renewable paraffinic diesel component in the low aromatic fuel composition (blend 6). When there was renewable paraffinic diesel component in the low aromatic fuel composition, the properties were less deteriorated or even improved. This shows that a renewable paraffinic diesel component is needed in the low aromatic fuel composition if good quality fuel composition is wanted (i.e. not all the properties are deteriorated.)

The results show that the present invention provides a low aromatic fuel composition with low aromatic content but still good low temperature properties. The low aromatic fuel composition of the present invention fulfils the requirements of EN 15940.

It will be obvious to a person skilled in the art that, as the technology advances, the inventive concept can be implemented in various ways. The invention and its embodiments are not limited to the examples described above but may vary within the scope of the claims.

Claims

1. A low aromatic fuel composition comprising at least two of the following components: 33 to 80 vol % renewable paraffinic diesel component, from 5 to 60 vol % fossil paraffinic diesel component and/or from 5 to 60 vol % GTL based diesel component, wherein the low aromatic fuel composition comprises more than 60 wt % paraffins, less than 40 wt % naphthenes and less than 0,5 wt % aromatics based on the total amount of the low aromatic fuel composition.

2. A low aromatic fuel composition according to claim 1 comprising less than 0,3 wt % aromatics, less than 0,2 wt % aromatics, less than 0,1 wt % aromatics.

3. A low aromatic fuel composition according to claim 1 which comprises more than 75 wt % paraffins, more than 85 wt % paraffins, more than 90 wt % paraffins, more than 95 wt % paraffins.

4. A low aromatic fuel composition according to claim 1 which comprises less than 25 wt % naphthenes, less than 15 wt % naphthenes, less than 10 wt % naphthenes, less than 5 wt % naphthenes.

5. A low aromatic fuel composition according to claim 1 wherein the low aromatic fuel composition fulfills the requirements of EN 15940.

6. A low aromatic fuel composition according to claim 1 wherein the low aromatic fuel composition comprises more than 85 wt % C14 to C18 hydrocarbons and less than 15 wt % C13 or smaller hydrocarbons and C19 or larger hydrocarbons combined.

7. A low aromatic fuel composition according to claim 1 comprising at least 10 vol % fossil paraffinic diesel component.

8. A low aromatic fuel composition according to claim 1 comprising less than 20 vol % GTL based diesel component.

9. A low aromatic fuel composition according to claim 1 comprising from 70 vol % to 80 vol % renewable paraffinic diesel component, 5 vol % to 15 vol % fossil paraffinic diesel component and 5 vol % to 15 vol % GTL based diesel component.

10. A low aromatic fuel composition according to claim 9 comprising 80 vol % renewable paraffinic diesel component, 10 vol % fossil paraffinic diesel component and 10 vol % GTL based diesel component.

11. A low aromatic fuel composition according to claim 1 comprising from 40 vol % to 60 wt % renewable paraffinic diesel component and from 60 vol % to 40 vol % fossil paraffinic diesel component.

12. A low aromatic fuel composition according to claim 1 wherein CFPP is less than -20 °C, preferably less than -25 °C, more preferably less than -30 °C.

13. A low aromatic fuel composition according to claim 1 wherein cetane number is more than 58, preferably more than 65, preferably more than 70.

14. A low aromatic fuel composition according to claim 1 wherein oxidation stability is more than 60 min, preferably more than 65 min, preferably more than 70 min.

15. A method for producing a fuel composition, the method comprising mixing at least two of the following components: renewable paraffinic diesel component, fossil paraffinic diesel component and/or GTL based diesel component wherein the amount of renewable paraffinic diesel component is 33 to 80 vol %, fossil paraffinic diesel component is from 5 to 60 vol % and/or GTL based diesel component is from 5 to 60 vol % and the total aromatics content of the low aromatic fuel composition is less than 0,5 wt-%.

16. Use of a renewable paraffinic diesel component for improving the properties of a low aromatic fuel composition comprising fossil paraffinic diesel component and/or GTL based diesel component wherein the amount of fossil paraffinic diesel component is from 0 to 60 vol % and the amount of GTL based diesel component is from 0 to 60 vol %, based on the total amount of the low aromatic fuel composition.