Abstract
Distillation is a unit operation of separating the components from a liquid mixture by selective evaporation and condensation. To obtain a pure liquid by distillation of a mixture must be applied in this process, numerous consecutive. Multistage distillation usually preferred instead of a single stage distillation. Fractional distillation is an example of a multistage distillation. Industrial-scale productions in all multistage or multitray distillation are applied. The composition of crude varies with its origin or geographical location. The contents of crude oil can be separated into different fractions with a series of fractional distillation processes.