To remain competitive, today’s refiners must employ all optimization and product control techniques available. The use of online physical property analyzers is one of the key features to reach those objectives because they measure important quality properties in the process directly.

Distillation is a physical method of separating the component substances from a liquid mixture by selective vaporization and re-condensation. Distillation is based on differences in volatilities of the components of the liquid mixture. The distillation curve is one of the most common quality parameters of liquid hydrocarbons such as naphtha, gasoline, kerosene, diesel and gas oil.