Solketal as a renewable fuel component in ternary blends with biodiesel and diesel fuel or HVO and the impact on physical and chemical properties

The need for new bio based drop-in components for combustion engine fuels and the availability of sustainable glycerol from biodiesel production has focused attention on isopropylidene glycerol (solketal). The present study investigates the physical and chemical behavior of solketal in ternary blends with diesel fuel/biodiesel. Hydrotreated vegetable oil (HVO) was used as renewable non-polar aliphatic diesel fuel substitute in biodiesel/solketal blends. HVO can be considered a prototype for other non-polar fuel components such as paraffinic fuel streams from Fischer-Tropsch or BtL processes. Surface tension, permittivity and aging behavior were analyzed. Furthermore, the cetane number (CN) and the viscosity was determined. Permittivity reflects the polarity of blends and their components with its change being an indicator of loss of physical and chemical stability. The antioxidant triphenyl phosphorothioate (TPPT) was also tested in some blends. The biodiesel blends B20, B30 and B40 enables single phased diesel fuel or HVO with varied solketal content (2 and 10%) at a constant biodiesel amount. No effect of solketal on fuel aging was observed. However, HVO-containing blends tend to lower the thermo-chemical stability relative to diesel fuel.