[0001] This invention is directed to a sustainable fuel and in particular a sustainable diesel.

[0002] It is an important environmental concern to reduce the reliance on fossil fuels. Such fossil fuels are derived from crude petroleum oil and include vehicle fuels such as gasoline and diesel. There is therefore a general need to create sustainable fuels which do not originate from fossil fuels. By far the most significant quantity of diesel fuel is extracted by fractional distillation from petroleum, so therefore attempts have been made to produce alternative diesel fuels which are instead derived from sustainable feedstocks.

[0003] Diesel may now be produced from a range of non-petroleum feedstocks, and when derived from biomass are referred to as biofuels. Diesel may alternatively be produced by a gas-to-liquid process, such as the Fischer- Tropsch process. These alternative, non-petroleum derived diesels may be classified according to their source. First-generation biofuels are directly related to a biomass that is generally edible, and examples of first-generation feedstock include animal and plant fats.

[0004] Second-generation biofuels are defined as fuels produced from a wide array of different waste feedstock, ranging from lignocellulosic feedstocks to municipal solid wastes as well as waste vegetable oils.

[0005] Third-generation biofuels are, at this point, related to algal biomass but could to a certain extent be linked to utilization of CO2 as feedstock.

[0006] Fourth-generation biofuels, which are also referred to as E-fuels utilise renewable energy as a source of electricity, hydrogen (derived from water) and CO2 to produce sustainable fuels.

[0007] To be considered a sustainable diesel, the diesel must be second, third or fourth generation. That is, the diesel is not derived from petroleum or biomass created for human consumption.

[0008] One form of diesel derived from biomass includes biodiesel, which is derived from plant or animal feedstock and consists of long chain fatty acid esters. Biodiesel however is not suitable on its own for use in internal combustion engines, unless the engine has undergone modification. Biodiesel is instead mixed with petroleum-derived diesel to use as a drop-in fuel. Biodiesel is currently restricted in the European Union to 7% by volume with the remainder made from petroleum-derived diesel. Generally, biodiesel feedstock will be first generation and therefore not sustainable.

[0009] Currently, the only biodiesels on the market are hydrotreated vegetable oils (HVO). HVO is a biofuel made by the hydrocracking or hydrogenation of vegetable oil. Such diesels are commonly referred to as “green diesels”, though the feedstocks for biodiesel may not necessarily be entirely first or second generation, and so not necessarily entirely sustainable. A significant problem with existing HVO biodiesel is that it is not compliant with the internationally recognised standards for commercial diesels and therefore cannot be used to completely replace diesel produced from petroleum.

[0010] In particular, HVO does not have the requisite density to meet standards such as EN 590, which is the standard published by the European Committee for Standardisation and which describes the physical properties that all automotive diesel must meet if it is to be sold in the European Union and several other European countries. Furthermore, the gross calorific value of HVO is lower than that of diesels that meet the EN 590 standard.

[0011] The present invention overcomes the issues with biodiesels such as HVO and is directed to the first sustainable diesel to be produced that is compliant with standard EN 590 and equivalent United States standard ASTM D975.

[0012] Whilst greenhouse gasses such as carbon dioxide will be released when sustainable diesel is combusted, relative to fossil fuel-derived diesels, sustainable diesel still results in a reduction in carbon dioxide emissions. This is because across its life cycle carbon dioxide absorbed by plants during their growth is roughly equivalent to the amount of carbon dioxide produced when the fuel is burned in a combustion engine. Therefore, replacement of a diesel derived from fossil fuel with a sustainable diesel reduces the net greenhouse gas emissions, which is calculated relative to emissions from fossil-fuel derived fuels. Entirely sustainable fuel would therefore have a zero net greenhouse gas emission in principle, though in practice it will not be as high as this due to energy costs during production. The ceiling for net greenhouse gas reductions is therefore around 80%.

Summary of the invention

[0013] According to the present invention there is provided a sustainable diesel comprising a hydrocarbon derived from tall oil. Tall oil is a viscous liquid obtained from waste wood pulp. In particular, it is a by-product of the kraft process when pulping mainly coniferous trees. Tall oil is a mixture of saponified fatty acids (30%-60%), resin acids (40%-60%, including mostly abietic and pimaric acids), and unsaponifiables (5%-10%). Refined products from tall oil include soaps, and rosin for sizing paper and textiles. The pulp and paper industry recovers about 450,000 tons of crude tall oil annually, and as such comprises firstly a second- generation feedstock, and also a waste product for which any use made is environmentally advantageous.

[0014] The hydrocarbon derived from tall oil may be defined by the following characteristics: density (at 15 °C): 805-820 kg/m ³ sulphur: max 10 mg/kg flashpoint: > 55 °C cetane number: min. 60 distillation, evaporated: 250 °C < 65 vol%, 350 °C min. 85 vol%.

[0015] The hydrocarbon derived from tall oil may be the fuel defined under EC number 700-916-7, and is available from UPM-Kymmene Oyj, Helsinki, Finland.

[0016] The sustainable diesel may further comprise a bio-aromatic consisting of a mixture which consists essentially of aromatic hydrocarbons having carbon numbers in the range of C9-C16 and boiling in the range of approximately 165°C to 290°C.

[0017] The bio-aromatic, sometimes also referred to as solvent naphtha or heavy aromatic, may be as defined by CAS No: 64742-94-5 and EC No: 265- 198-5 and is available from Ekobenz Sp. z o.o., Kleszczow, Poland. The bio- aromatic is a product derived from an ethanol-to-gasoline conversion process, also known as EtG. The ethanol is a second generation fuel, has not been produced from an edible feedstock, and is therefore sustainable. The gasoline production process produces 1 ) Bio-LPG, 2) Light-Hydrocarbons (used in the gasoline) and 3) heavier bio-aromatics, which was previously considered a waste product. Surprisingly, the bio-aromatics have been found to, when used in a diesel fuel, bring the properties of the diesel in line with standard such as EN 590. Bio-aromatics, such as the present bio-aromatic, would not normally be found in a commercially available diesel fuel.

[0018] The sustainable fuel may further comprise a biodiesel. The biodiesel may be a fatty acid methyl ester (FAME) and in particular may be rapeseed methyl ester (RME), or may be an HVO. FAME and RME are generally first generation, and therefore are not sustainable, however diesel according to the present invention comprises a far higher proportion of sustainable fuels than any commercially available diesel that complies with EN 590.

[0019] The sustainable diesel may consist of the following components in the following ranges: 92.5% v/v +/- 0.5% hydrocarbon derived from tall oil, 6.5% v/v biodiesel and 1 % v/v +/- 0.5% v/v bio-aromatic.

[0020] In a preferred composition, the composition consists of 92.5% v/v hydrocarbon derived from tall oil defined by EC number 700-916-7, 6.5% v/v RME, 1 % v/v bio-aromatic defined by CAS No: 64742-94-5 and EC No: 265-198- 5.

[0021] In an alternative preferred composition, the composition consists of 45% v/v hydrocarbon derived from tall oil defined by EC number 700-916-7, 40% v/v HVO and 15% v/v bio-aromatic defined by CAS No: 64742-94-5 and EC No: 265-198-5.

[0022] Competitions according to the present invention may also comprise tall oil-derived diesel and RME. Such compositions may comprise at least 10% v/v RME with the remainder being tail-oil derived diesel. Compositions may comprise between 10-30% v/v RME with the remainder being tail-oil derived diesel. [0023] Aspects of the present invention will now be discussed by way of example only.

Example 1

A formulation comprising 92.5% Tail-oil derived diesel, defined under EC number 700-916-7 and obtained from UPM-Kymmene Oyj, Helsinki, Finland, 6.5% RME, and 1 % bio-aromatic as defined by CAS No: 64742-94-5 and EC No: 265-198-5 obtained from Ekobenz Sp. z o.o., Kleszczow, Poland was made, and tested in accordance with diesel standards EN5-90 and ASTM D975. Each component was analysed before use. Gained analytical data was added to a blend model which then determines the exact formulation within the given range. A mini blend/pi lot made up out of ca. 5 L and was blended to analyse the key parameters before continuing with the bulk scale. The bulk blend was made at atmospheric pressure and temperature. Each component added was initially weighed precisely by using scales or volumetric meters. The blending tank was stirred 3- 4 time to ensure that the diesel was homogenous. Samples were being taken at the end of the process for analysis. The results of the tests are reproduced in Table 1 below and show that the formulation complies with both standards.

Table 1

Example 2

A series of comparative tests were performed to show that diesel fuel according to the present invention meets the requirements of EN-590 and ASTM D975, whereas other fuels do not. A formulation comprising 92.5% Tail-oil derived diesel, defined under EC number 700-916-7, 6.5% RME, and 1 % bio-aromatic as defined by CAS No: 64742-94-5 and EC No: 265-198-5 was made, and tested in accordance with diesel standards EN 590 and ASTM D975. A further fuel comprising 92.5% Tail-oil derived diesel, defined under EC number 700-916-7 and 6.5% RME was made. HVO fuel G21/1130 was also obtained and the density of the three fuels were tested by oscillating ll-Tube according to EN ISO 12185. The results of the test are reproduced in Table 2 below and show that the formulation comprising the bio-aromatic complies with EN590 (density of between 0.820 and 0.8450 kg/L) whereas the comparative fuel without the bioaromatic and the HVO diesel do not.

Table 2

Example 3

A further series of tests were conducted to compare sustainable diesel according to the present invention with HVO and EN590 compliant petroleum derived diesel.

A formulation (LG21/205) comprising 92.5% Tail-oil derived diesel, defined under EC number 700-916-7, 6.5% RME, and 1 % bio-aromatic as defined by CAS No: 64742-94-5 and EC No: 265-198-5 was made, and tested in accordance with diesel standards EN 590 and ASTM D975. A further formulation (LG21/201 ) comprising 45% Tail-oil derived diesel, defined under EC number 700-916-7, 40% HVO (obtained from Neste Corporation), and 15% bio-aromatic as defined by CAS No: 64742-94-5 and EC No: 265-198-5 was made, and tested in accordance with diesel standards EN 590 and ASTM D975. LG21/205 and LG21/201 were compared with HVOs G21/1130 and G21/1253, and EN590 compliant petroleum-derived diesels G21/1281 and G21/1058. The results are shown in Table 3. As shown, firstly, the HVO diesels G21/1130 and G21/1253 lack the density to comply with EN 590. Secondly, the Gross and Net Calorific Values of the HVO diesels are lower than LG21/205 and LG21/201 as well as the EN590 diesels G21/1281 and G21/1058. Therefore there is less energy available per litre of HVO than for the other diesels. LG21/201 has the highest Gross and Net Calorific Value of any of the diesels tested. Furthermore, LG21/201 has a lower Cold Filter Plugging Point (CFFP) than LG21/205.

Table 3

Example 4

Two further blends were made. LG21/106 comprises 90% Tall oil-derived diesel, defined under EC number 700-916-7, and 10% RME and LG21/163 which comprises 70% Tall oil-derived diesel, defined under EC number 700-916-7, and 30% RME. Both blends were tested in accordance with diesel standards EN 590 and ASTM D975 as shown in Table 4. As shown, both LG21/106 and LG21/163 comply with both EN 590 and ASTM D975 in particular with reference to density. LG21/106 in particular has higher Gross and Net calorific Values as compared to the HVO blends in Table 3.

Table 4