Solid contents of palm-based biofuel mixtures with respect to storage and handling

The solid content (SC) of biofuel mixtures obtained from mixing crude palm oil (CPO) with medium fuel oil (MFO), and refined palm oil (RPO) with petroleum diesel (PD), was investigated. The SC of these mixtures will impact on their applications, storage and handling. The concentrations of CPO and RPO in the investigated mixtures ranged from 5 to 90% for the CPO-MFO system and from 0 to 10% for the RPO-PD system. For CPO/MFO mixtures, their SC exhibited eutectic behavior over the temperature range measured (5-20 °C). Eutectic minima were observed in the 80-90% CPO concentration range for all temperatures. These eutectic minima are due to dilution effects and the formation of van der Waals hydrogen bonds between the asphaltenes in MFO and the triacylglycerols. RPO/PD mixtures did not show any eutectic behavior. The SC for the RPO/PD mixtures were observed to be below 4% at 5 °C after 24 h of tempering and 0% at 15 °C over the same tempering period. When semi-solid, ambient PO is used as a biofuel, heating is required to liquify it for ease of handling. When mixed with petroleum-based fuels in the correct proportion, present handling and storage equipment and facilities are adequate for handling these mixtures.