Heterogeneous catalysts for the production of hydrotreated cracked vegetable oil

ABSTRACT

A high-pressure/high-temperature reactor was used in batch and continuous mode to obtain hydrotreated cracked vegetable oil (HCVO). The effect of six catalysts such as Pt and Pd on active carbon, CoMo, NiMo and Pt+Pd on Al₂O₃ and ZSM-5 were investigated in batch experiments for cracked vegetable oil (CVO) upgrading. CVO was produced in-house from rapeseed oil. Reaction conditions were 300–380 °C at 50–150 bar hydrogen. The stripped and condensed product was gathered continuously in intervals of 30–60 min. Both, batch and continuous products were separated into an oil phase and a water phase. Physical properties were determined, including higher heating value (HHV), acid/iodine number, viscosity, density and elemental composition. HCVO showed HHV up to 46.6 MJ/kg (CVO: 43.5 MJ/kg), acid number of 2.8 mg_KOH/g (CVO: 80.5 mg_KOH/g) and oxygen content of 0.32 wt% (CVO: 5.27 wt%). HHV of HCVO is in the range of fossil diesel fuel. Pt/C is the most suitable catalyst for the production of HCVO under the used experimental conditions. HCVO may be used as a fossil fuel substitute based on renewable raw material. GCMS-FID was used for the quantitative analysis of composition. Up to 73 wt% of the samples were quantifiable.

KEYWORDS:

• Deoxygenation
• hydrotreating
• hydrotreated cracked vegetable oil
• catalyst
• biofuel

Acknowledgements

The present work is supported by a scholarship of the Hanns-Seidel-Stiftung by funds from the Federal Ministry of Education and Research, Germany. GCMS-FID analyses were performed at the Thünen Institute of Wood Technology and Wood Biology, Hamburg, Germany.

Conflict of interest

The authors declare that they have no conflict of interest.