Solvent Dewaxing – continued.

Dewaxed oil is collected from the center of the filter, made to go through a heat exchanger (to absorb some heat) and then routed to a furnace. In the furnace the temperature of the dewaxed oil (and the solvent) is increased and introduced into an evaporator. In the evaporator, the solvent rises to the top and the dewaxed oil is collected at the bottom.

Usually two solvents are used: toluene, which dissolves the oil and maintains fluidity at low temperatures, and methyl ethyl ketone (MEK), which dissolves wax at low temperatures and acts as a wax precipitating agent.