The purpose of this refinery process is to remove long chain hydrocarbons that solidify at a relatively high freezing point. Their removal lowers the pour point of the product (lubricating base stock). The overall goal would be to lower the pour point without lowering the viscosity.
The process overview is illustrated below:
Additional notes to the dewaxing process:
1. I-alkanes are preferred in the lube oil base stock due to their lower freezing point.
2. Straight chain alkanes are preferred due to their lower viscosity.
3. Additional important properties of lube oil base stocks include volatility and thermal stability
4. All the above properties are controlled by changing the molecular composition of the hydrocarbons and by the use of an additive package.
5. The two types of dewaxing methods include sovent (physical process, separation by solubility) and catalytic (chemical process, breaking bonds) dewaxing.
Insert references from text either
process diagrams or description