Fuel composition for a diesel engine

Abstract

The invention is directed to a fuel composition for diesel engines. The fuel composition comprises 0.1-99% by weight of a component or a mixture of components produced from biological raw material originating from plants and/or animals and/or fish. The fuel composition comprises 0-20% of components containing oxygen. Both components are mixed with diesel components based on crude oil and/or fractions from Fischer-Tropsch process.

Claims

1. A method for producing an isomerized biological component comprising: (1) providing a feed stream of fatty acids having saturated or unsaturated hydrocarbon chains having carbon numbers within a range of C6-C24, fatty acid esters having saturated or unsaturated hydrocarbon chains having carbon numbers within a range of C6-C24, or both, derived from at least one biological raw material; (2) hydrodeoxygenating the feed stream to form n-paraffins having carbon numbers within a range of C6-C24; and (3) isomerizing the n-paraffins to form an isomerized biological component comprising isoparaffins, wherein the isomerized biological component is suitable for use as a diesel fuel for a diesel engine and has a cetane number higher than 60 and a turbidity point lower than −30° C.

2. The method according to claim 1, wherein the biological raw material is chosen from animal-based material, plant-based material, fish-based material, and mixtures thereof.

3. The method according to claim 1, wherein the biological raw material is chosen from vegetable oils, animal fats, fish oils, and mixtures thereof.

4. The method according to claim 1, wherein the biological raw material is chosen from animal-based fats; fats contained in milk; recycled fats of the food industry; wood-based fats or oils; non-wood, plant-based fats or oils; fats contained in plants bred by means of gene manipulation; fish oils; and mixtures thereof.

5. The method according to claim 1, wherein the biological raw material is a non-wood plant based oil chosen from rapeseed oil, colza oil, canola oil, tall oil, sunflower oil, soybean oil, hempseed oil, olive oil, linseed oil, mustard oil, palm oil, peanut oil, castor oil, and coconut oil.

6. The method according to claim 1, wherein the biological raw material is an animal-based fat chosen from lard, tallow, and train oil.

7. The method according to claim 1, wherein the n-paraffins have carbon numbers in the range of C12-C24.

8. The method according to claim 1, wherein the isomerized biological component has a density less than a crude oil based conventional diesel fuel.

9. The method according to claim 1, wherein the isomerized biological component has a density less than a rapeseed oil methyl ester-based fuel.

10. The method according to claim 1, wherein the isomerized biological component leaves no impurity residues.

11. The method according to claim 1, wherein the isomerized biological component comprises a measurable amount of .sup.14C.

12. The method according to claim 1, wherein each of the hydrodeoxygenation and isomerization steps is run in a counter-current manner.

13. A method for producing a fuel composition, which comprises at least one isomerized biological component, comprising: (1) providing a feed stream of fatty acids having saturated or unsaturated hydrocarbon chains having carbon numbers within a range of C6-C24, fatty acid esters having saturated or unsaturated hydrocarbon chains having carbon numbers within a range of C6-C24, or both, derived from at least one biological raw material; (2) hydrodeoxygenating the feed stream to form n-paraffins having carbon numbers within a range of C6-C24; and (3) isomerizing the n-paraffins to form an isomerized biological component comprising isoparaffins, wherein the isomerized biological component is suitable for use as a diesel fuel for a diesel engine has a cetane number higher than 60 and a turbidity point lower than −30° C.; and (4) forming the fuel composition with the isomerized biological component.

14. The method of producing a fuel composition of claim 13, wherein forming the fuel composition comprises mixing the isomerized biological component with a diesel component, which is derived from crude oil, fractions from a Fischer-Tropsch process, or combinations thereof.

15. The method of producing a fuel composition of claim 14, wherein the diesel component is derived from crude oil.

16. The method of producing a fuel composition of claim 15, wherein the fuel composition is 0.1 to 60% by volume isomerized biological component.

17. The method of producing a fuel composition of claim 16, wherein the fuel composition has a cetane number higher than 60 and a turbidity point lower than −15° C.

18. The method of producing a fuel composition of claim 13, further comprising a component containing oxygen chosen from aliphatic alcohols, ethers, fatty acid esters, and mixtures containing the same.

19. The method of producing a fuel composition of claim 18, wherein the component containing oxygen is a fatty acid methyl ester.

20. A method for reducing nitrogen oxide emission of an engine comprising using the fuel composition of claim 15.

21. The method according to claim 13, wherein forming the fuel composition comprises combining the isomerized biological component with a crude oil-based conventional diesel fuel.

22. The method according to claim 13, wherein the fuel composition comprises from 30 to 60% by volume isomerized biological component.

23. The method according to claim 13, wherein the fuel composition has a cetane number higher than 60 and a turbidity point less than or equal to −15° C.

24. An isomerized biological component produced by a process comprising: (1) providing a feed stream of fatty acids having saturated or unsaturated hydrocarbon chains having carbon numbers within a range of C6-C24, fatty acid esters having saturated or unsaturated hydrocarbon chains having carbon numbers within a range of C6-C24, or both, derived from at least one biological raw material; (2) hydrodeoxygenating the feed stream to form n-paraffins having carbon numbers within a range of C6-C24; and (3) isomerizing the n-paraffins to form an isomerized biological component comprising isoparaffins, wherein the isomerized biological component is suitable for use as a diesel fuel for a diesel engine and has a cetane number higher than 60 and a turbidity point lower than −30° C.

25. A fuel composition comprising at least one isomerized biological component produced by a process comprising: (1) providing a feed stream of fatty acids having saturated or unsaturated hydrocarbon chains having carbon numbers within a range of C6-C24, fatty acid esters having saturated or unsaturated hydrocarbon chains having carbon numbers within a range of C6-C24, or both, derived from at least one biological raw material; (2) hydrodeoxygenating the feed stream to form n-paraffins having carbon numbers within a range of C6-C24; and (3) isomerizing the n-paraffins to form an isomerized biological component comprising isoparaffins, wherein the isomerized biological component is suitable for use as a diesel fuel for a diesel engine and has a cetane number higher than 60 and a turbidity point lower than −30° C.

26. The fuel composition of claim 25, further comprising a diesel component derived from crude oil, fractions from a Fischer-Tropsch process, or combinations thereof.

27. The fuel composition of claim 26, wherein the diesel component is derived from crude oil.

28. The fuel composition of claim 27, wherein the fuel composition is 0.1 to 60% by volume isomerized biological component.

29. The fuel composition of claim 28, wherein the fuel composition has a cetane number higher than 60 and a turbidity point lower than −15° C.

30. The fuel composition of claim 25, further comprising a component containing oxygen chosen from aliphatic alcohols, ethers, fatty acid esters, and mixtures containing the same.

31. The fuel composition of claim 30, wherein the component containing oxygen is a fatty acid methyl ester.

Description

GENERAL DESCRIPTION OF THE INVENTION

(1) The object of the invention is to provide a more environmentally friendly fuel composition for diesel engines containing components of biological origin, and also meeting the quality requirements for diesel fuels under low temperature conditions.

(2) The fuel composition for diesel engines of the invention, containing components of biological origin, comprises at least one component produced from a biological starting material obtained from plants, animals or fish, diesel components based on crude oil and/or fractions from Fischer-Tropsch process, and optionally components containing oxygen.

(3) The characteristic features of the fuel composition for diesel engines containing components of biological origin are presented in the appended claims.

DETAILED DESCRIPTION A OF THE INVENTION

(4) It was surprisingly found that the diesel fuel composition of the invention, containing components of biological origin, also meets the quality requirements for diesel fuels under low temperature conditions. The composition of the diesel fuel of the invention comprises the following:

(5) a) 0.1 to 99% by volume, preferably 0.1 to 80% by volume of a component or a mixture of components produced from biological raw material originating from plants and/or animals and/or fish;

(6) b) 0 to 20% by volume of components containing oxygen selected from the group consisting of aliphatic alcohols such as methanol and ethanol, ethers, fatty acid esters such as methyl and ethyl esters, water, and mixtures containing the same; both components a) and b) being mixed as an emulsion or dissolved in diesel components based on crude oil and/or fractions from Fischer-Tropsch process.

(7) Component a) produced from biological raw material originating from plants and/or animals and/or fish, referred to as the biological component in the present specification, is obtained by hydrogenating and decomposing fatty acids and/or fatty acid esters to give a hydrocarbon having a carbon number of 6-24, typically n-paraffin as the product having a carbon number of 12-24, and optionally by isomerizing the hydrocarbon, typically n-paraffin, thus obtained to give isoparaffin. The hydrocarbon is preferably isomerized.

(8) The biological raw material originating from plants and/or animals and/or fish is selected from the group consisting of vegetable oils, animal fats, fish oils and mixtures thereof containing fatty acids and/or fatty acid esters. Examples of suitable materials are wood-based and other plant-based fats and oils such as rapeseed oil, colza oil, canola oil, tall oil, sunflower oil, soybean oil, hempseed oil, olive oil, linseed oil, mustard oil, palm oil, peanut oil, castor oil, coconut oil, as well as fats contained in plants bred by means of gene manipulation, animal-based fats such as lard, tallow, train oil, and fats contained in milk, as well as recycled fats of the food industry and mixtures of the above.

(9) The basic component of a typical vegetable or animal fat is triglyceride i.e., a triester of glycerol and three fatty acid molecules having the structure presented in the following formula I:

(10) where RI, R2, and R3 are hydrocarbon chains, and R, R2, and R3 may be saturated or unsaturated C6-C24 alkyl groups. The fatty acid composition may vary considerably in biological raw materials of different origin.

(11) n-paraffin, iso-paraffin or mixtures thereof produced from the biological raw material may be used as a diesel fuel component in accordance with the properties desired for the diesel fuel. Fractions from Fischer-Tropsch-process typically contain high levels of n-paraffin and, optionally, they may be isomerized either simultaneously during the processing of the

(12) ##STR00001##
component of biological origin or separately therefrom, or they may be used as such.

(13) The biological component may be produced, for instance, with a process comprising at least two steps and optionally utilizing the counter-current operation principle. In the first hydrodeoxygenation step of the process, optionally running counter-current, the structure of the biological raw material is broken, compounds containing oxygen, nitrogen, phosphor and sulphur as well as light hydrocarbons as gas are removed, and thereafter, olefinic bonds are hydrogenated. In the second isomerization step of the process, optionally running counter-current, isomerization is carried out to give branched hydrocarbon chains, thus improving the low temperature properties of the paraffin.

(14) Biological raw material originating from plants, animals or fish and containing fatty acids and/or fatty acid esters, selected from vegetable oils, animal fats, fish oils and mixtures thereof, is used as the feed stock.

(15) High quality hydrocarbon component of biological origin, particularly useful as a component of a diesel fuel, as an isoparaffinic solvent and as a lamp oil, is ob¬tained as the product having a high cetane number that may even be higher than 70. Also, with a turbidity point lower than −30° C. a cetane number higher than 60 can still be achieved. The process can be adjusted according to the desired cetane number and turbidity point.

(16) Advantages of the diesel fuel composition of the present invention include superior performance at low temperatures and an excellent cetane number compared to solutions of prior art using FAME-based components like RME. Problems associated with the performance at low temperatures may be avoided by isomerizing waxy n-paraffins having a carbon number comparable with that of fatty acids to give isoparaffins. The properties of the products thus obtained are excellent, especially with respect to diesel applications, the n-paraffins typically have cetane numbers higher than 70, and isoparaffins higher than 60, and thus they have an improving effect on the cetane number of the diesel pool, which clearly makes them more valuable as diesel components. Moreover, the turbidity point of the isomerized product may be adjusted to the desired level, for example below −30° C., whereas the corresponding value is about 0° C. for RME and more than +15° C. for n-paraffins. Table 1 below compares the properties of an isomerized biological component, RME, and a commercial diesel fuel.

(17) TABLE-US-00001 TABLE 1 Density Cetane Turbidity Product (kg/m.sup.3) number point (° C.) Isomerized biological component C 800 >60 −30 RME −880 −50 −0 Diesel fuel EN 590 820-845 >51 0 to −15

(18) Fouling of engines is considerably diminished and the noise level is clearly lower when using the diesel fuel composition of the invention in comparison with similar prior art fuels of biological origin containing FAME components, and further, the density of the composition is lower. The composition does not require any modifications of the automobile technology or logistics. Higher energy content per unit volume may be mentioned as a further advantage compared to RME.

(19) The properties of the diesel fuel composition of biological origin according to the invention correspond to those of a high quality diesel fuel based on crude oil, it is free of aromates and, in contrast to FAME, it leaves no impurity residues.

(20) Nitrogen oxide emissions due to the fuel composition of the invention are lower that those from a similar FAME-based product, and further, the particle emissions are clearly lower, and the carbon portion of the particles is smaller. These significant improvements in the emissions of the fuel composition of biological origin are environmentally very important.

(21) The invention will now be illustrated by means of the following examples without intending to limit the scope thereof.

EXAMPLES

Example 1

(22) The following Table 2 compares the emission characteristics of a conventional diesel fuel used in Europe in summer, EN 590 (DI), to those of a composition containing 60% by volume of hydrogenated and isomerized tall oil (TOFA), and 40% by volume of the European summer diesel fuel EN 590.

(23) TABLE-US-00002 TABLE 2 60% b.v. TOFA + Characteristic Unit 40% b.v. DI DI Turbidity point ° C. −15 −8 Cetane number 61.2 55.9 Aromates % b.w. 8.7 19.2 Total aromates (IP391) % b.v. 9.1 20.0 Polyaromates (1P391) % b.v. 0.8 1.6 n-paraffins % b.w. 14_7 24.5 i-paraffins % b.w. 34.2 26.1 Naphtenes % b.w. 42.4 30.2 b.w. = by weight b.v. = by volume

Example 2

(24) Table 3 below compares the emission characteristics of a high quality reformed crude oil based diesel fuel available on the Finnish market (DITC, produced by Fortum Oyj), to those of compositions containing 30% by volume of hydrogenated and isomerized tall oil (TOFA), and 70% by volume of DITC, or containing 30% by volume of tall oil methyl ester (MME), and 70% by volume of DITC.

(25) TABLE-US-00003 TABLE 3 30% b.v. TOFA 30% b.v. MME Characteristic Unit DITC 70% b.v. DITC 70% b.v. DITC Cetane number 51 57 48 NO, emissions % −1 to −4 +3 (compared to DITC) Particles % −3 +22 carbon % −10 to −30 0 to −10 PAH % ±0 ±0 Combustion noise decreases ±0 b.v. = by volume