Winter waxing
High Melt Point Esters are Fatty Acid Methyl Esters with melt points above ambient - typically between 10°C to 40°C.
HMPEs are usually seen in winter as either suspended flakes in the biodiesel, or white/yellow cream at the bottom of drums. Adding petrol to a warm, melted mix does not prevent the HMPEs re-solidifying on cooling.
Treatment is by filtering out the solids at the ambient temperature the fuel will be used at, or Water Washing with cold water. The initial level of HMPEs in the produced fuel may also be reduced by doing a cold Water Prewash.
The presence of HMPEs in biodiesel is feedstock related, with processing method playing only a very minor part. Please note, there is some speculation that the Whole Batch Demeth method may produce more HMPEs than other methods although this is unconfirmed and needs further research before a final conclusion is reached.
- High Melt Point Esters
HMPEs at bottom of barrel
A closer look at the ball formation
HMPE balls on the side of a barrel
HMPEs after bio is filtered off
HMPEs forming around the coil of a beer chiller
A closer look
Severe HMPEs. Source Bionoob
Severe HMPEs. Source Bionoob
Severe HMPEs. Source Bionoob
