FUEL COMPOSITION FOR A DIESEL ENGINE

1 - 7 . (canceled)

8 . A method for reducing nitrogen oxide emissions of a diesel engine, comprising:

(a) preparing a diesel fuel of biological origin consisting of at least one component produced by a process comprising:

(1) providing a feed stream of fatty acids, fatty acid esters, or both, derived from at least one biological raw material originating from animals or from animals in combination with plants and/or fish;

(2) hydrodeoxygenating the feed stream to form n-paraffins; and

(3) isomerizing the n-paraffins to form isoparaffins, in which the diesel fuel of biological origin is free of aromatics and has a cetane number higher than 60; and

(b) using the diesel fuel of biological origin in a diesel engine,

in which the nitrogen oxide emissions of the diesel engine are less than the nitrogen oxide emissions of the same engine using a diesel fuel derived from crude oil.

9 . The method of claim 8 , further comprising combining the diesel fuel of biological origin with a diesel fuel derived from crude oil before using the diesel fuel of biological origin in the diesel engine.

10 . The method of claim 8 , in which the biological raw material is selected from animal-based fats, fats contained in milk, recycled fats of the food industry, or mixtures thereof.

11 . The method of claim 8 , in which the fatty acid esters are triglycerides.

12 . The method of claim 8 , in which the diesel fuel of biological origin has a turbidity point lower than −30° C.

13 . A method for reducing nitrogen oxide emissions of a diesel engine, comprising:

(a) selecting a diesel fuel of biological origin consisting of at least one component produced by a process comprising:

(1) providing a feed stream of fatty acids, fatty acid esters, or both, derived from at least one biological raw material originating from animals or from animals in combination with plants and/or fish;

(2) hydrodeoxygenating the feed stream to form n-paraffins; and

(3) isomerizing the n-paraffins to form isoparaffins, in which the diesel fuel of biological origin is free of aromatics and has a cetane number higher than 60; and

(b) using the diesel fuel of biological origin in the diesel engine,

in which the nitrogen oxide emissions of a diesel engine are less than the nitrogen oxide emissions of the same engine using a diesel fuel derived from crude oil.

14 . The method of claim 13 , further comprising combining the diesel fuel of biological origin with a diesel fuel derived from crude oil before using the diesel fuel of biological origin in the diesel engine.

15 . The method of claim 13 , in which the biological raw material is selected from animal-based fats, fats contained in milk, recycled fats of the food industry, or mixtures thereof.

16 . The method of claim 13 , in which the fatty acid esters are triglycerides.

17 . The method of claim 13 , in which the diesel fuel of biological origin has a turbidity point lower than −30° C.

18 . A diesel fuel of biological origin consisting of at least one component produced by a process comprising:

(1) providing a feed stream of fatty acids, fatty acid esters, or both, derived from at least one biological raw material originating from animals or from animals in combination with plants and/or fish;

(2) hydrodeoxygenating the feed stream to form n-paraffins; and

(3) isomerizing the n-paraffins to form isoparaffins,

in which the diesel fuel of biological origin is free of aromatics, has a cetane number higher than 60, and reduces nitrogen oxide emissions of a diesel engine as compared to the same engine using a diesel fuel derived from crude oil.

19 . The diesel fuel of claim 18 , in which the biological raw material is selected from fats, oils, and mixtures thereof.

20 . The diesel fuel of claim 18 , wherein the biological raw material is selected 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.

21 . The diesel fuel of claim 18 , in which the biological raw material originates from a combination of animals and plants.

22 . The diesel fuel of claim 18 , in which the fatty acid esters are triglycerides.

23 . The diesel fuel of claim 18 having a turbidity point lower than −30° C.

24 . A method of producing a diesel fuel of biological origin consisting of at least one component produced by a process comprising:

(1) providing a feed stream of fatty acids, fatty acid esters, or both, derived from at least one biological raw material originating from animals or from animals in combination with plants and/or fish;

(2) hydrodeoxygenating the feed stream to form n-paraffins; and

(3) isomerizing the n-paraffins to form isoparaffins;

in which the diesel fuel of biological origin is free of aromatics and has a cetane number higher than 60.

25 . The method of claim 24 , in which the diesel fuel of biological origin reduces nitrogen oxide emissions of a diesel engine as compared to the same engine using a diesel fuel derived from crude oil.

26 . The method of claim 24 , in which the biological raw material is selected from animal-based fats, fats contained in milk, recycled fats of the food industry, or mixtures thereof.

27 . The method of claim 24 , in which the hydrodeoxygenating process is performed in a countercurrent manner.

28 . The method of claim 24 , in which the isomerizing process is performed in a countercurrent manner.

29 . The method of claim 27 , in which the isomerizing process is performed in a countercurrent manner.

30 . The method of claim 24 , in which the fatty acid esters are triglycerides.

31 . The method of claim 24 , in which the diesel fuel has a turbidity point lower than −30° C.