Gel point (petroleum)

Gel point is the temperature at which diesels or biodiesels freezes solid and can no longer flow by gravity or be pumped through fuel lines. This phenomenon happens when a fuel reaches a low enough temperature whereby enough wax crystals have formed to prevent any movement in the oil.

For the fuel to become pumpable again, it needs to be brought above the gel point temperature to the Ungel point, which is typically near its pour point. However, most of the waxes will still remain in solid form and the fuel as to be warmed up further till its Remix temperature in order to completely remelt and redissolve the waxes.

Anti-gel additives are therefore commonly added to diesel or biodiesels where cold temperature is expected. They act to reduce the formation of wax crystals in the fuel, thereby lowering the pour point and the gel point of the fuel. Anti-gel additives may not necessarily affect the cloud point.

ee also

*Pour point
*Cloud point
*Cold filter plugging point
*Petroleum

References