As a process engineer, your task is to design a debutanizer column operating at 1 atm, equipped with a partial reboiler and a total condenser. The feed consists of 900 kg/h of propane, 180 kg/h of n-butane, and 210 kg/h of n-pentane, presented as a saturated vapor. The specific requirements from your customer are to achieve a 95% recovery of n-pentane in the bottoms and a 98% recovery of butane and lighter compounds in the distillate. For this process, reflux is returned as a saturated liquid, and it can be assumed that constant molal overflow (CMO) conditions apply. Moreover, equilibrium in the column is best represented by constant relative volatilities.

• Determine
• a) the total number of stages
• b) the feed stage without Aspen simulation.
• To achieve this, follow the steps to find N_min (Fenske equation), R_min (Underwood equation), R (relation between R and R_min), N (Gilliland correlation), and Nfeed (Kirkbride or Fenske equation).
•  Explain and show calculation for each part ?