Technology

Second generation renewable fuels such as HEFA, HEFA-SPK (Sustainable Aviation Fuel or SAF), renewable diesel and bionaphtha are produced by hydroprocessing Used Cooking Oils (UCOs) or/and different vegetable oils like Canola Oil, Corn Oil, Camelina Oil, Rapeseed Oil, Sunflower Oil, Soybean Oil, Palm Oil, Tallow & Jatropha. The bio-based feeds have a higher content especially of phosphorous and oxygen but lower metal contents such as Na, Ca, K & Mg compared with fossil-based feedstock.

The operating pressure depends on Nitrogen content of the feed. The Hydrogen (H₂) consumption depends on the type of feed since palm oil has 0.5-0.6 double bond per chain while sunflower oil has 1.6 double bond per chain:

• Palm oil: 40-45 Nm³/m³
• Sunflower oil: 100-110 Nm³/m³ only for double bonds saturation

Hydrogen requirements for hydroprocessing triglycerides are typically:

• Cracking: 65 Nm³/m³
• Decarbonylation: 65-70 Nm³/m³ f
• Hydrodeoxygenation: 200-210 Nm³/m³
• Decarbonylation + Methanation: around 270 Nm³/m³
  If methanation occurs then the advantage of decarbonylation + decarboxylation over hydrodeoxygenation in terms oh H₂ consumption shall disappear.