GB2412665A

GB2412665A - Fuel composition comprising rapeseed oil methyl ester

Info

Publication number: GB2412665A
Application number: GB0506402A
Authority: GB
Inventors: Charles Fraser
Original assignee: DOVE INTERNAT
Current assignee: DOVE INTERNAT
Priority date: 2004-03-30
Filing date: 2005-03-30
Publication date: 2005-10-05
Anticipated expiration: 2025-03-30
Also published as: GB2412665B; GB0506402D0; GB0407138D0

Abstract

A fuel composition comprising: (i) a first fuel component consisting of a fuel which is within Swedish Environmental Class 1; (ii) a second fuel component consisting of a gasoil having a sulphur content of less than 50 pads per million; and (iii) a third fuel component consisting of methyl ester which is derived from rapeseed oil.

Description

24 1 2665

FUEL COMPOSITION

The present invention relates to a fuel composition and a method for the production thereof. More particularly, the present invention relates to a diesel fuel composition.

Diesel is a fuel that is commonly used by heavy-duty engines, tractors, trucks and other heavy duty road vehicles. Diesel fuel contains a broad mixture of hydrocarbons produced as distillates, residual materials or as blends of the two during the refining of crude petroleum. Diesel fuels contain approximately 60-80% paraffinic materials and 20-40% aromatic naphthenic materials. The operational quality of a diesel fuel is indicated by the cetane number. The cetane number of a diesel fuel usually falls into the range of 30-60.

Approximately 30% of all vehicle fuel sold in the UK is diesel fuel. Gasoline or petrol fuel makes up the bulk of the remainder of vehicle fuel sold in the UK. The cost of running a vehicle on diesel tends to be less than that for a vehicle running on petrol, since diesel is 25-30% more efficient than petrol. Diesel is also perceived to have a number of environmental and health benefits over petrol. In particular, diesel contains no lead and produces virtually no carbon monoxide.

Nevertheless, emissions from vehicles operating on diesel do contribute significantly to atmospheric pollution in built up areas. Exhaust emissions have increased rapidly in recent years despite emission controls which have been introduced. This is largely due to the rise in the number of vehicles in use on the roads.

Companies involved in oil refinery and fuel production continue to look for ways to reduce emissions from vehicles operating on their fuels. Pollutants in the emission spectrum of fuels including petrol and diesel which are sought to be reduced include nitrogen oxides, carbon monoxide, aromatics and particulates. However, in addition, it has been increasingly recognised that compounds known as polycyclic aromatic hydrocarbons (PAHs) in fuel emissions are hazardous to human health.

PAHs result from incomplete combustion of fuel in vehicles. A large number of PAHs have been the subject of studies which have found that these compounds are mutagenic carcinogens. Accordingly, it is desirable to reduce the levels of PAH as well as other emissions from fuels such as diesel fuel.

In some countries such as Sweden, incentives in the form of reduced taxes exist for fuels having low levels of harmful emissions. However, fuels having the properties required to be entitled to reduced tax levels have been expensive to produce. On the other hand, cheaper fuels are of poorer quality and have not had such low emission levels.

It is an aim of the present invention to provide a fuel composition which has comparable or reduced levels of emissions compared with known low emission fuel compositions, whilst utilising a relatively low quality fuel component.

According to the present invention there is provided a fuel composition comprising: (i) a first fuel component consisting of a fuel which is within Swedish Environmental Class 1; (ii) a second fuel component consisting of a gasoil having a sulphur content of less than 50 parts per million; (iii) a third fuel component consisting of methyl esterwhich is derived from rapeseed oil.

Swedish environmental class 1 fuel is a class of fuel defined by Swedish energy legislation for the purposes of diesel fuel tax differentiation. This fuel preferably has the properties set out in the following table.

TABLE 1

Parameter Class 1 Sulphur (mass content), max. (%) 0.001 Aromatics (volume content), max. (%) 5 q PAH'' (volume content), max. (%) <0.02 l Cetane index, min. 50 Density (kg/m3) 800 - 820 Distillation: l - Initial boiling point, min. ( C) 180 - Temp. at 95% recovery, max. ( C) 285 l

_

1) triaromatics and higher PAN The first fuel component is preferably a petroleum/mineral based or derived fuel.

The second fuel component is suitably a type of diesel fuel known in the art. The second fuel component is preferably an automotive diesel. The second fuel component suitably has the properties of UK-specification ultra-low-sulphur diesel. The second fuel component is preferably an ultra-low sulphur diesel.

This fuel (ii) is suitably of a comparatively poor quality compared to component (i). The second fuel component preferably has one or more of the following properties: Cetane index of 49 or higher Density greater than 817kg/m3 at 15 C Total aromatics content greater than 5% v/v Preferably, the second fuel component is automotive diesel fuel or gasoil within British Standard EN 590-1997. The properties of such a fuel are set out below in Table 2.

TABLE 2

| Property Level Test method.

| Flash point ( C) above 55 ISO 2719.

| Carbon residue (% m/m) <0.30 ISO 10370 | (on 10% distillation residue) | Ash content (% m/m) <0.01 EN 26245 l Water content (mg/kg) <200 ASTM D1744 | Particulate matter (mg/kg) <24 DIN 51 419.

Copper strip corrosion rating class 1 ISO 2160 (3 h at 50 C) Oxidation stability (g/m3) <25 ASTM D2274 Sulphur content (% m/m) <0.20 EN 24260/lSO 8754 CFPP C EN 116 CFPP grade A <+5 CFPP grade B <o CFPP grade C <-5 CFPP grade D <-10 CFPP grade E <-15 CFPP grade F <- 20 Density at 15 C (kg/m3) min 820 max 860 ISO 3675/ASTM D4052 Viscosity at 40 C (mm2/S) min 2.00 max 4.50 ISO 3104 Cetane number >49 ISO 5165 Cetane index >46 ISO 4264 Total aromatics content (% VN) 20 Distillation ISO 3405 % VN recovered at not less than 285 C % VN 95 A preferred feature of the second fuel component is that under distillation according to ISO 3405 less than 63% v/v is recovered at 250 C.

Examples of biodiesel standards are given in Table 2A.

TABLE 2A

Parameter French Standard German Standard (DIN V51606) Ash 0.03% (m/m) Aspect Clear Colour <12 Density at 15 C 870-900 kg/m3 0.875-0.90 g/ml Viscosity at 40 C 3.5-5.0 mm2/s 3.5-5.0 mm2/s Flash point > = 100 C > = 110 C Distillation min. 95% at 360 C min. 95% at 360 C Water content < = 200 mg/kg < = 300 mg/kg.

Cetane > = 49 > = 49 (DIN 51773) . 1.

Carbon residue max. 0.30% (m/m) 0.5% (ISO 10370) Total acidity < = 0.5 mgKOH/g < = 0.5 mgKOH/g Dl N 51558-1 CFPP < = -10 C 01/10 to 14/04 < = 10 C 16/10 to 28/02 < = -20 C Methylester %wt. > = 96.5 > = 98.5 l Methanol < = 0.1% (m/m) < = 0.3% (m/m) l Phosphorus < = 10 mg/kg < = 10 mg/kg l Teneur en metaux alcalins < = 0.5 mg/kg Na + K< = 0.5 mg/kg l Na or K 1 iodine value (WIJS) < = 115 < = 115 DIN 53241 -1 l Free glycerine < = 0. 02% (m/m) < = 0.02% (m/m) l Monoglycerides < = 0.8% (m/m) < = 0.8% (m/m) l Diglycerides < = 0.2% (m/m) < = 0.4% (m/m) l Triglycerides < = 0.2% (m/m) < = 0.4% (m/m) l Total glycerol < = 0.25% (m/m) < = 0.25% (m/m) Copper strip corrosion Class 1 It has been surprisingly found by the applicant that a fuel comprising Swedish Environmental class 1 fuel, together with the relatively low-quality fuel component (ii) and rapeseed methyl ester delivers the improved emission spectrum normally associated with conventional petroleum-based Swedish Environment class 1 fuels, whilst delivering lower nitrogen oxide emissions and better fuel economy than the sum of the parts would appear to dictate. Furthermore, such a fuel can be made available in significantly larger quantities than conventional Swedish Environment class 1 fuel.

Accordingly, it is apparent that lower quality fuels can be utilised in a way that maximises the available benefits that can be derived from using an oxygenate, such as the rapeseed methyl ester, in a fuel composition.

It has been surprisingly found by the applicant that a fuel composition comprising these three fuel components has low levels of PAH. The improvements in emission of hydrocarbons, PAHs and 1-nitropyrene for this fuel are substantial not only over commonly available mineral diesel blends, but also other fuels. In fact, it has been found by the applicant that the level of PAH emissions forthe complete fuel composition of the present invention is lower than that which might be deduced from adding together the PAH levels for each component individually. Accordingly, it is believed by the applicant that there is a synergy in the combination of these three fuel components together which leads to a catalytic reduction in the PAH output of the fuel.

It has also been found by the applicant that the fuel composition of the present invention also has reduced emissions of nitrogen oxides, carbon dioxide and particulates.

Preferably, the third fuel component is present at a level sufficient to reduce polycyclic aromatic hydrocarbon output of the fuel compared with the same fuel without the third fuel component.

Preferably, the third fuel component is present at a level of from 0.3 v/v% to 7.8 v/v%, and more preferably, from 4 v/v% to 5 v/v%.

Preferably, the first fuel component constitutes from 5 to 80 v/v % of the fuel composition. Preferably, when the third fuel component constitutes from 4 to 7.8 v/v % of the fuel composition, the first fuel component is present at a level of from 40 to 80 v/v %. When the third fuel component constitutes 0.3 to 4 % of the fuel composition, the first fuel component usually is present at a level of from 5 to 50 v/v %.

Preferably, the second fuel component constitutes from 20 to 95 v/v % of the fuel composition. When the third fuel component constitutes from 4 to 7.8 v/v %, the second fuel component is usually present at a level of from 20 to 95 v/v %. When the third fuel component constitutes from 0.3 to 4 v/v %, the second fuel component is usually present at a level of from 50 to 95 v/v % of the fuel composition.

Preferably the second component should have a high cetane number to aid an efficient burn. Quantities of GTL (gas-to-liquids) product can be sourced to boost cetane content of this component.

Preferably, the first fuel component has a cetane index of at least 50.4 or 50.0.

Preferably the first fuel component constitutes from 50 to 70 v/v %, the second fuel component constitutes from 20 to 40 v/v % and the third fuel component comprises from 4 to 5 v/v % of the fuel composition.

Preferably the level of polycyclic aromatic hydrocarbon in the fuel composition is less than 0.95 and more preferably less than 0.02 volume %.

Preferably the fuel composition has the following characteristics:

TABLE 3

Test Method Limits Water content mg/kg ASTM D1744 <200 Particulate contaminant mg/kg DIN 51419 <24 Oxidation Stability g/m3 ASTM D2274 <25 Density at 15 C kg/l ASTM D4052 min 0.800 max 0.860 Distillation % v/v recovered at 250 C <65 Distillation % v/v recovered at 345 C >95 Distillation % v/v recovered at 370 C >95 Ash content % m/m EN 26245 <0. 01 Flash point C ISO 2719 >55 Copper Corrosion (3 h at 50 C) ISO 2160 class 1 Kinematic Viscosity at 40 C mm2/s ISO 3104 min 2.0 max 3.5 Cetane Index ISO 4264 >46 Cetane Number ASTM D613 >49 Sulphur content % m/m IP 373 <0.2 Microcarbon residue on 10% residue % ISO 10370 <0.3 (mum) Aromatics vol % IP 391 <20 Polycyclic aromatic hydrocarbons vol % IP 391 <0.95 According to a second aspect of the present invention there is provided a method for producing a fuel composition comprising blending a first fuel component consisting of a fuel which is within Swedish Environmental Class 1, with a second fuel component consisting of a lowsulphur diesel fuel and a third fuel component consisting of a methyl ester which is derived from rapeseed oil.

The details of the components of a composition produced by a method according to the second aspect of the invention are preferably as described above in relation to the first aspect of the invention. In particular, the second fuel component is preferably a gasoil and preferably has a sulphur content of less than 50 parts per million.

It is postulated that the combination of three components, approximating to the specifications detailed in the attached schedule, gives an end product that delivers the improved emissions spectrum normally associated with Swedish Class 1 diesel fuels; whilst delivering lower NOx emissions and better fuel economy than the sum of the parts would appear to dictate. It is suggested that the majority of the improvement over what would be expected from the individual source components (in areas such as NOx and other emissions parameters) is arrived at directly as a result of improvement in fuel economy. The addition of the second component, an environmentally less benign fuel than Swedish Class 1 diesel, togetherwith rapeseed methyl esterofsufficientquality, is believed to result in an end product that has materially better fuel economy than many Swedish Class 1 diesel fuels whilst delivering comparable - or better - emissions performance in regulated emissions and demonstrating a potentially clear catalytic effect reducing emissions of PAM compounds from the fuels. It is believed that this catalytic effect is present over a range. The presence of the biodiesel, as an oxygenate, may serve to make combustion more efficient; however additional oxygen availability may make itself useful in catalytic as well as combustion processes - and these catalytic effects are different for different fuels and types of fuel, in combination.

In fuels according to the present invention it appears that apparently lower quality fuels can be utilised in a way that may maximise the available benefits that are possible to derive from the combination of different fuels in the presence of an oxygenate.

A fuel according to the present invention is believed to be in many ways superior to some very high quality Swedish Class 1 diesel fuels of conventional type. Forthe most part, in legislative terms, Sweden has represented the state of the art in development of reformulated diesel fuels. This invention represents a diversion away from the accepted theory on clean diesel fuels.

The present invention will now be described in further detail with reference to the

following examples.

Example 1

A fuel composition was prepared by blending together the three components listed in Table 4 below under the codes 001-00, 002-00 and 003-00. The blend, Blend 4, comprises 62.95% component 1 (code 001 -00) 33.0% component 2 (code 002-00) and 4.05% component 3 (code 003-00).

Component 1 (001-00) is a diesel fuel within Swedish Environmental Class 1.

Component 2 (002-00) is an ultra-low sulphur diesel fuel within British Standard EN 590:1997 (see above).

Component 3 (003-00) is a methyl ester derived from rapeseed oil.

TABLE 4

Test Method 001 -00 002-00 003-00 Flash Point, C ISO 2719* 74 72 140 Micro Carbon Residue on 10% ISO 10370* <0.1 <0.1 0.3 Residue, % (m/m) Ash Content, % (m/m) EN 26245* <0.010 <0.010 <0.010 Water, mg/kg ASTM <50 115 238 D 1744 Particulate Contaminant, mg/kg DIN 51419 1 2 3 Copper Corrosion 3 h at 100 C ISO 2160 1 1 1 Oxidation Stability, g/m3 ASTM 2.0 2.0 2.0 D2274 Sulphur Content, % (m/m) IP 373 <0 001 <0.001 <0.001 Cold Filter Plugging Point, C EN 116* <-30 -24 -12 Density at 15 C, kg/L ASTM 0.8184 0.8215 0.8833 D4052 Kinematic Viscosity at 40 C, mm2/s ISO 3104* 2.048 2.116 4.522 Cetane Number ISO 5165* 50. 4 54.8 Cetane Index ISO 4264* 51.4 53.1 56.9 Distillation ASTM D86 I.B.P, C 188.0 187.0 320.5 5% v rec. at, C 206.0 208.0 331.5 10% v rec. at, C 212.0 214.0 333.0 20% v rec. at, C 219.0 223.02 334.0 30% v rec. at, C 224.0 230.0 335.0 40% v rec. at, C 229.0 237.0 335.5 50% v rec. at, C 235.0 245.0 336.0 60% v rec. at, C 241.0 252.0 336.5 70% v rec. at, C 247.0 262.0 338.0 80% v rec. at, C 255.0 271.0 339.5 90% v rec. at, C 269.0 286.0 346.5 95% v rec. at, C 273.0 296.0 346.5 F.B.P, C 297.0 309.0 346.5 % v rec. at 250 C, % (v/v) 69.5 57.0 0.0 % v rec. at 350 C, % (v/v) >99.5 >99.0 >99.0 % v rec. at 370 C, % (v/v) >99.5 >99.0 >99.0 Recovery, % (v/v) 99.5 99. 0 99.0 Residue, % (v/v) 0.5 1.0 1.0 Loss, % (v/v) 0.0 0.0 0.0 Carbon, % (m/m) ASTM 85.5 85.8 76.8 D5291 Cross Calorific Value, MJ/kg IP 12 44. 38 44.80 44.65 Calculated r Net Calorific Value, MJ/kg from IP 12 41. 34 41.86 42.08 Hydrogen, % (m/m) ASTM 14.38 13.90 12.12 D5291 Blend 4 had the properties set out below in Table 5.

TABLE 5 - BLEND 4

Test Method Result | Appearance Visual* Clear & Bright l Colour Visual* Yellow Water and Sediment, % (v/v) Visual* Nil Water, mg/kg ASTM D1744 84 Particulate Contaminant, mg/kg DIN 51419 2.00 Oxidation Stability, g/m3 ASTM D2274 3. 0 Density at 15 C, kg/J ASTM D4052 0.8219 Distillation ASTM D86 10% v rec. at, C 210.0 50% v rec. at, C 240.0 90% v rec. at, C 286.0 95% v rec. at, C 302.0 F.B.P, C 321.0 % v rec. at 250 C, % (v/v) 63.0 % v rec. at 350 C, % (v/v) >99.0 % v rec. at 370 C, % (v/v) >99.0 Recovery, % (v/v) 99.0 Residue, % (v/v) 1.0 Loss, % (v/v) 0.0 Carbon, % (m/m) ASTM D5291 85.82 Hydrogen, % (m/m) ASTM D5291 14.02 l Cross Calorific Value, MJ/kg IP 12 46.24 Net Calorific Value, MJ/kg Calculated from IP 12 43.36.

Ash Content, % (m/m) EN 26245* <0.005.

Flash Point, C ISO 2719* 69.0 Copper Corrosion 3 h. at 50 C ISO 2160 1 Kinematic Viscosity at 40 C, mm2/s ISO 3104* 2.12 Cetane Index ISO 4264* 51.5 Cold Filter Plugging Point, C IP 309.29 Cetane Number ASTM D613* 51.1.

Sulphur Content, mg/L IP 373 1.1 icro Carbon Residue on 10% ISO 10370 <0. 1.

Residue, % (m/m) Test results conducted on the blended product indicated that the blended product had surprisingly low levels of emissions including polycyclic aromatic hydrocarbon emissions. The results of test are set out in Figures 1-14, which illustrate in graph form the levels of emissions of particulates (Figures 1 and 2), polycyclic aromatic hydrocarbons (Figures 3 and 4), sulphur dioxide (Figures 5 and 6), nitrogen oxides (Figures 7 and 8), hydrocarbons (Figures 9 and 10), carbon monoxide (Figures 11 and 12) and carbon dioxide (Figures 13 and 14).

Example 2

Blend 5 consists of a mixture of 11.1 % component 1, 88.6% component 2 and 0.3% component 3. The properties of Blend 5 are set out below in Table 6.

TABLE 6

Limit Typical | Flash Point min 56 C 72.5 1.

l Carbon Residue max 0.3 0.09 l Ash Content max 0.01 0.001 | Water Content max 0.02 % m/m < 0.01 % | Particulate Matter (mg/kg) max 24 < 2 Copper Strip Corrosion class 1 class 1 Oxidation Stability (g/m3) max 25 2.0 Sulphur Content (% m/m) max 0.005 < 0.003 % Cold Filter Plugging Point ( C) max -20 All Year < - 30 Density at 15 C min 820 < 828 Viscosity at 40 C min 2.0 < 2.40 Cetane Number min 49 54 Cetane Index min 49 53 Distillation % v/v rec. at 250 C max <65% 58% % v/v rec. at 350 C min 85% >99% % v/v rec. at 370 C min 95% >99% % v/v rec. at 345 C min 95% >99% Aromatics Content (total) max 20% <19% lC In general, many "cleaner" diesel fuel types contain a higher mole count of Hydrogen; through selecting more of such fractions of base material that have high Hydrogen content partly in order to reduce - relatively - Carbon emissions. This, in itself, will lead to additional uptake of Oxygen from wherever it is available; leading to reductions in NOx formation - but increases in nitration of other materials, such as Polycyclic Aromatic Hydrocarbons (PAM) due to the presence of surplus Nitrogen in the pre-exhaust phase that would otherwise normally form additional NOx production. Therefore any NOx saving is likely to be offset to some extent by a tendency for levels of some different emissions to be higher than might otherwise be the case with alternative formulations such as those detailed in the claims in this application.

Conversely, we believe that we can demonstrate the ability to selectively offset nitration of PAH through the inclusion of a "true oxygenate" in pre-determined proportions; with a view to maximising this effect.

Further, we believe this can demonstrate that availability of active PAH in the pre- exhaust phase that would otherwise become nitrated to N-PAH is instead available to react with other PAH or other atmospheric compounds to produce - primarily - larger compounds in the soot fraction. This, further, may also provide the basis for overall reductions in CO emissions that we expect to see from this scenario.

In this scenario achieving surplus Oxygen, without addition of certain additives designed to strip Oxygen from the air-mix, enables further oxidation of the active PAH fraction (possibly facilitated to some extent by trace levels of Pottassium Hydroxide present in the rapeseed methylester (RME); and may create additional energy through Hydrogen atoms being split from these PAH and combining with other elements or compounds. Beyond a certain level of RME content in the blend it appears that this effect is countered by intrinsic availability of Nitrogen in the RME itself leading to progressively greater levels of nitration of PAH and overall NOx formation.

In this way we believe it is possible to take a medium-quality ultra-lowsulphur diesel feedstock and effect disproportionately greater reductions in PAH and N-PAH formation through having increased Hydrogen availability from an additional high- hydrogen content component; with reduced availability of free Nitrogen present (after accounting for NOx formation), as NOx formation is allowed to occur normally whilst Oxygen availability for further oxidisation remains abundant - due to the presence of RME as a "true oxygenate".

Any use of some types of cetane improver as an additive could be likely to create higher Carbon Monoxide, whilst requiring high levels of Oxygen from the air-mix.

This would leave little Oxygen available in the combustion mix (pre and post- exhaust) to otherwise combine with ambient Nitrogen for normal production of NOx.

As such the use of some types of additives, whilst reducing NOx formation, might actually be increasing availability of Nitrogen in the pre-exhaust phase; where temperatures are high - aswell as pressure.

Most fuels contain a broad spectrum of components that may combine and react with one another in different ways, depending on the exact combustion conditions; l} producing a variety of different emissions components. Increased availability of Nitrogen in the pre-exhaust phase is likely to lead to a higher level of nitration of other compounds within the emissions. As such, we feel that the use of additives designed to strip excess levels of Oxygen from the air-mix may in some cases be counter-productive.

A "true oxygenate" such as rapeseed methylester holds within it a relatively pre- determined level of Oxygen that is generally at a higher level than that of standard diesel fuel feedstocks. Therefore RME as a blendstock allows combustion to take place without stripping excessive levels of Oxygen from the air-mix; allowing N02 and N03 production as normal. As such, we feel that it should be preferable to seek to slightly increase NOx formation, without specific addition of Nitrogen-based additives, in order to maximise the capability to limit the nitration of compounds; such as PAH into N-PAH (nitrated polycyclic polyaromatic hydrocarbons), for

example.

It is this that we believe can demonstrate a clear synergistic effect through the use of high-quality components in specific blend ratios to derive disproportionately greater benefit in overall reductions of PAH and N-PAH emissions whilst seeking to maximise combustion efficiency.

We further believe that feedstocks in proportions and qualities as filed in the claims depict a series of blends leading to our definition as to the likely optimum blend configuration at which these synergistic effects are likely to be observed. In particular, increases in Nitrogen availability from any source - including the percentage content of RME in the blend - will likely eradicate some of this beneficial effect.

Increased production of water vapour may, in part, stem from Hydrogen atoms breaking away from some PAH molecules, assisted by high Oxygen availability. This may also lead to a Hydroxide presence during combustion, possibly triggering additional reactions to break-down PAH compounds.

We might postulate that seeking slight increases in NOx formation and a disproportionate increase in of water vapour production during combustion could be an indicator for maximum reductions in both PAH and N-PAH emissions, whilst maximising available energy production from the Mel.

It is further suggested that so long as a relatively high Hydrogen content is kept, yet- lower-quality feedstock can be incorporated as the second component and that this will probably allow for slightly-greater levels of RME content; whilst retaining the synergistic benefits described. This is likely to be so because a greater quantity of PAH will exist in the exhaust from a lower-quality blend; needing greater levels of Oxygen to break them down and sustaining a slightly-higher availability of ffielNitrogen from the RME.

As such, we believe that the above can be shown to demonstrate the concept by which these specific blends that we are claiming can promote the breaking down of PAH compounds and limit production of N-PAH compounds to an extent greater than that which would be expected from use of those constituent feedstocks in isolation, or in other blend ratios.

The theories detailed are base on observations made from a review of published research materials from various sources; and provisionallysupported by reported test results on a trial blend that we have created that has demonstrated significantly-better fuel economy benefits.

The applicant draws attention to the fact that the present invention may include any feature of combination of features disclosed herein either implicitly or explicitly or any generalization thereof, without limitation to the scope of any of the present claims. In view of the foregoing description it will be evident to a person skilled in the art that various modifications may be made within the scope of the invention. Iq

Claims

CLAIMS: 1. A fuel composition comprising: (i) a first fuel component

consisting of a fuel which is within Swedish Environmental Class 1; (ii) a second fuel component consisting of a gasoil having a sulphur content of less than parts per million; (iii) a third fuel component consisting of methylesterwhich is derived from rapeseed oil.
2. A fuel composition as claimed in claim 1, wherein the third fuel component is present at a level sufficient to reduce polycyclic aromatic hydrocarbon output of the fuel compared with the same fuel without the third fuel component.
3. A fuel composition as claimed in claim 1 or claim 2, wherein the third fuel component is present at a level of from 0.3 v/v % to 7.8 v/v %.
4. A fuel composition as claimed in claim 3, wherein the third fuel component is present at a level of from 4 v/v % to 5 v/v %.
5. A fuel composition as claimed in any one of claims 1 to 4, wherein the first fuel component constitutes from 5 to 80 v/v % of the fuel composition.
6. A fuel composition as claimed in claim 5, wherein the first fuel component constitutes from 40 to 80 v/v % and the third fuel component constitutes 4 to 7.8 v/v % of the fuel composition.
7. A fuel composition as claimed in claim 5, wherein the first fuel component constitutes from 5 to 50 v/v % and the third fuel component constitutes 0.3 to 4 % of the fuel composition.
8. A fuel composition as claimed in any one of claims 1 to 4, wherein the second fuel component constitutes from 20 to 95 v/v % of the fuel composition. no
9. A fuel composition as claimed in claim 8, wherein the second fuel component constitutes from 20 to 95 v/v % and the third fuel component constitutes from 4 to 7.8 v/v % of the fuel composition.
10.A fuel composition as claimed in claim 8, wherein the second fuel component constitutes from 20 to 95 v/v % and third fuel component constitutes from 0.3 to 4 v/v % of the fuel composition.
11. A fuel composition as claimed in any one of claims 1 to 10, wherein the first fuel component has a cetane index of at least 50.0.
12.A fuel composition as claimed in any one of claims 1 to 11, wherein the first fuel component constitutes from 50 to 70 v/v % the second fuel component constitutes from to 40 % and the third fuel component comprises from 4 to 5 % of the fuel composition.
13.A fuel composition as claimed in any one of claims 1 to 12, wherein the level of polycyclic aromatic hydrocarbons is less than 0.95 vol %.
14.A fuel composition as claimed in any one of the preceding claims and having the following characteristics: Test Method Limits Water content mg/kg ASTM D1744 <200 Particulate contaminant mg/kg DIN 51419 <24 Oxidation Stability g/m3 ASTM D2274 <25 Density at
15 C kg/l ASTM D4052 min 0.800 max 0.860 Distillation % v/v recovered at 250 C <65 Distillation % v/v recovered at 345 C >95 l Distillation % v/v recovered at 370 C >95 Ash content % m/m EN 26245 <0.01 Flash point C ISO 2719 >55 Copper Corrosion (3 h at 50 C) ISO 2160 class 1 Kinematic Viscosity at 40 C mm2/s ISO 3104 min 2.0 max 4.5 Cetane Index ISO 4264 >46 Cetane Number ASTM D613 >49 Sulphur content % m/m IP 373 <0.2 Microcarbon residue on 10% residue % ISO 10370 <0.3 (mom) Aromatics vol % IP 391 <20 Polycyclic aromatic hydrocarbons vol % IP 391 <0.95 15. A fuel composition as claimed in any one of the preceding claims, and wherein the second fuel component is automotive diesel fuel within British Standard EN 590:1997.
16. A fuel composition as claimed in any one of the preceding claims, and wherein the second fuel component is a low sulphur diesel. In
17. A method of producing a fuel composition comprising blending a first fuel component consisting of a fuel which is within Swedish Environmental Class 1 with a second fuel component consisting of a gasoil having a sulphur content of less than 50 parts per million and a third fuel component consisting of a methyl ester which is derived from rapeseed oil.