Blending of renewable fuels

A method for producing an aviation fuel blend having a measured viscosity of 12 mm2/s or below at −40° C., and 10 mm2/s or below at −30° C., measured in accordance with an EN ISO 3104 (1996) standard, which measured viscosity is at least 0.032 mm2/s lower than a calculated viscosity CsB for the aviation fuel blend, the calculated viscosity CsB being calculated for the aviation fuel blend based on viscosities of the individual fuels thereof at a respective temperature by using a formula (III):

• CsB=EXP([(VBIB)*LN(1000)]/[1−VBIB]) (III),
• where VBIB=ΣViVBIi,
• where Vi is a volume ratio of an individual fuel, and
• VBIi=[LN(Csi)]/[LN(1000*Csi)],
• where VBi is a viscosity index for an individual fuel, and
• Csi is a viscosity of an individual fuel,
• the method comprising:
• mixing individual fuels of petroleum derived jet fuel, and renewable paraffinic middle distillate fuel, together in an amount consisting of 5-40 vol-% of renewable paraffinic middle distillate fuel and up to 95 vol-% of petroleum-derived jet fuel;
• the method also comprising producing the renewable paraffinic middle distillate fuel from vegetable oil, animal fat, fish fat, palm oil, rapeseed oil, cooking oil, biogas, algae oil and/or microbial oil,
• and/or
• the method also comprising producing the renewable paraffinic middle distillate fuel from hydrogenated fatty acid materials and/or hydrogenated triglyceride materials;
• wherein the petroleum-derived jet fuel complies with at least one aviation fuel standard selected from ASTM D1655, DEFSTAN 91-91, JET A, and JET A-1;
• wherein the renewable paraffinic middle distillate fuel is produced via a Fischer-Tropsch process and isomerisation, and/or wherein the renewable paraffinic middle distillate fuel is produced via hydrodeoxygenation and isomerisation;
• and
• wherein the renewable paraffinic middle distillate fuel contains aromatic compounds in an amount of at most 0.5 vol-% and iso-paraffins in an amount of at least 80 vol-%, the rest being other paraffins and the renewable paraffinic middle distillate fuel comprises at least 70 wt-% of C15 to C18 paraffins.