Pour Point Depressent & Wax Inhibition

Virtually all paraffinic mineral oil base stocks contain small amounts of waxy materials. As the temperature of the oil is decreased, some of the waxy components come out of solution as tiny crystals, and the solution begins to appear hazy to the naked eye. The temperature at which this occurs is called the cloud point. As additional wax precipitates, the crystals grow into plates and, finally, if the temperature is decreased far enough, the plates will grow together to form a three-dimensional network that totally immobilizes the oil. This solidification process is sometimes referred to as gelation. The lowest temperature at which the oil is fluidis called the pour point.

When wax crystals form, pour point depressants co-crystallize along with the wax species present in the oil and modify the growing pattern of wax crystal structures. Additionally, the wax crystals are kept apart from each other by the PPD backbone, and as a result of this steric hindrance, the wax crystals are no longer able to form three-dimensional structures that inhibit flow.