Search

EP-4569052-B1 - IMPROVEMENTS IN FUELS

EP4569052B1EP 4569052 B1EP4569052 B1EP 4569052B1EP-4569052-B1

Inventors

  • LENNON, JASON ALLEN
  • GOLISZ, SUZANNE

Dates

Publication Date
20260506
Application Date
20230809

Claims (7)

  1. A fuel composition comprising renewable diesel obtained by the hydrodeoxygenation of fats and oils and from 70 to 1000 ppm of one or more low temperature enhancing additives selected from: (a) a copolymer comprising units of formula (I): and units of formula (II): wherein R is an alkyl group and each of R 1 and R 2 is an alkyl or alkenyl group having 10 to 14 carbon atoms, preferably 12 to 14 carbon atoms and which copolymer has a number average molecular weight of 4000 to 25000, preferably 5000 to 20000, more preferably 6000 to 15000.
  2. A method of improving the low temperature properties of a fuel composition comprising renewable diesel obtained by the hydrodeoxygenation of fats and oils, the method comprising admixing into the composition one or more low temperature enhancing additives selected from: (a) a copolymer comprising units of formula (I): and units of formula (II): wherein R is an alkyl group and each of R 1 and R 2 is an alkyl or alkenyl group having 6 to 22 carbon atoms; wherein the method depresses the cloud point of the fuel composition by at least 1 °C
  3. The use of one or more low temperature enhancing additives selected from: (a) a copolymer comprising units of formula (I): and units of formula (II): wherein R is an alkyl group and each of R 1 and R 2 is an alkyl or alkenyl group having 6 to 22 carbon atoms; to improve the low temperature properties of a fuel composition comprising renewable diesel obtained by the hydrodeoxygenation of fats and oils; wherein the use depresses the cloud point of the fuel composition by at least 1 °C.
  4. A method or use according to claim 2 or claim 3 wherein the one or more low temperature enhancing additives comprises a copolymer comprising units of formula (I): and units of formula (II): wherein R is an alkyl group each of R 1 and R 2 is an alkyl group having 10 to 14 carbon atoms, preferably 12 to 14 carbon atoms and which copolymer has a number average molecular weight of 4000 to 25000, preferably 5000 to 20000, more preferably 6000 to 15000.
  5. A composition, method or use according to any preceding claim wherein the copolymer comprises from 40 to 60 mol % of units of formula (I) and from 60 to 40 mol % of units of formula (II).
  6. A composition, method or use according to any preceding claim wherein the fuel comprises a blend of renewable diesel and a further diesel fuel.
  7. A composition, method or use according to claim 6 wherein the further diesel fuel is selected from biodiesel, mineral diesel and mixtures thereof.

Description

The present invention relates to improvements in fuel compositions comprising renewable diesel and in particular to improving the properties of fuel compositions comprising renewable diesel at low temperatures. As fuels cool crystals begin to form within the fuels. These can cause problems during storage, transportation and combustion of the fuel. Three measurements are commonly taken to assess the low temperature performance of diesel fuel. Standardised tests have been devised to measure the temperature at which the fuel hazes (the cloud point - CP), the lowest temperature at which a fuel can flow (the pour point - PP) and the lowest temperature at which fuel flows through a filter (the cold filter plugging point - CFPP); and the changes thereto caused by additives (ΔCP, ΔPP, ΔCFPP). The standardised tests for measuring PP and, especially, CP and CFPP are among the common working tools for persons skilled in the art. A standard test used to measure the pour point of diesel fuels is ASTM D5949. The cloud point (CP) of a fuel is the temperature at which a cloud of wax crystals first appears in a liquid when it is cooled under conditions prescribed in the test method as defined in ASTM D2500 or ASTM D5773. At temperatures below the cloud point but above the pour point, the wax crystals can reach a size and shape capable of plugging fuel lines, screens, and filters even though the fuel will physically flow. These problems are well recognized in the art and have a number of recognised test methods such as the CFPP value (cold filter plugging point, determined in accordance with DIN EN116 or ASTM D6371). Tests such as these were introduced to give an indication of low temperature operability as the cloud point test was considered to be too pessimistic. Cold flow improvers (CFls) and wax anti-settling additives (WASAs) have been developed to ameliorate the problems of wax precipitation below the cloud point in fuels, and their effect can be studied by the test methods described above, comparing the results between unadditised fuels and additised fuels. Some such additives may assist in keeping the so-called "waxes" in solution in the fuel; others may alter their crystal morphology or size, so that filterability and pourability are maintained in spite of precipitation. WO2020/008182 describes the use of additives which counteract negative interactions between other additives in the fuel at low temperatures. The present invention relates in particular to improving the low temperature properties of fuel compositions comprising renewable diesel. In recent years environmental pressures have meant that greener alternatives to fossil fuels have been increasingly used. It is now common to replace some or all of diesel obtained from petroleum sources with diesel obtained from natural or renewable sources. However inclusion of a renewable diesel component can have a significant impact on the properties of a fuel at low temperatures. The chemical nature of renewable diesel is quite different to that of mineral diesel. Mineral diesel is derived from petroleum and comprises a mixture of alkanes comprising a high degree of branching, along with aromatic and olefinic compounds. Renewable diesel is prepared by the hydrodeoxygenation of fats and oils and comprises primarily straight chain alkanes. These have a different chemical composition to mineral diesel. Because the chemical nature of renewable diesel differs to that of mineral diesel, different waxes and precipitates form as these fuels cool. For blended fuels the wax crystals which form in one component may be less soluble in other components of the fuel. This can lead to increased problems, for example with filterability of the fuel, at low temperatures. Due to the different compositions of these fuels, additives which improve the low temperature properties of mineral diesel fuels do not necessarily improve the low temperature properties of fuel compositions comprising renewable diesel. The present inventors have found that certain additives are especially effective at improving the low temperature properties of fuel compositions comprising renewable diesel. In particular the inventors have found that certain additives depress the cloud point of said fuel compositions. According to a first aspect of the present invention there is provided a fuel composition comprising renewable diesel and one or more low temperature enhancing additives selected from: (a) a copolymer comprising units of formula (I): and units of formula (II): wherein R is an alkyl group and each of R1 and R2 is an alkyl or alkenyl group having 6 to 22 carbon atoms; Additive (a) may be prepared by copolymerising vinyl ester monomers and fumaric acid monomers and then esterifying the acid residues. Preferably additive (a) is prepared by copolymerising vinyl ester monomers and dialkyl fumarate monomers. Additive (a) is preferably a copolymer prepared by reacting monomers of vinyl ester of formula (III): a