Vacuum generation plays a key role in refinery operations. The most common application of multi steam ejectors is in the distillation column of an oil refinery.Vacuum distillation is used in oil refineries if long-chain hydrocarbons require Separation. By applying a vacuum column, the boiling point of the substances to be distilled is lowered, making separation of the hydrocarbons easier. Also in gas refineries vapor recovery proccessing can accomplish using ejector cycle with lower price and more efficiency results. In a petrol refineries particulary high demands are placed on vacuum systems used in this industrial area.