BOULEGANE YassminaDAOUDI IkramAZZOUZ Salaheddine (Encadrant)2025-11-182025-11-182025http://dspace.ensti-annaba.dz:4000/handle/123456789/949This work investigates the cryogenic air separation process at the Bellara industrial site and it’s based on Number of theoretical stages' estimation of the high pressure (HP) and low pressure (LP) distillation columns. The separation is treated as a binary system consisting of nitrogen and oxygen. With insufficient detailed process data, the McCabe–Thiele graphical method was employed under the simplifying assumptions based on a steady-state Aspen hysys simulation. It was found that 28 and 41 theoretical stages are necessary in the HP and LP columns, respectively, amounting to a total of 69 theoretical stages in the distillation system. Using theoretical column efficiencies of 80% for the HP column and 60% for the LP column, the estimated numbers of real stages are about 35 for the HP column and 68 for the LP column which is consistent with the expected range. This result provides a realistic approximation of the number of stages of this double system distillation column. Therefore, for preliminary work, the study shows that graphical methods, combined with software simulation techniques today is widely reliable. Future work will aim to develop algorithms to better reflect real operating conditions.enThesis