This set of Mass Transfer Question Bank focuses on “Fractionation Column-Ponchon & Savarit Method”
1. The Ponchon Savorit method is applicable for determining negligible heat loss.
Explanation: As this method includes enthalpy concentration data it helps to determine the negligible heat loss.
2. External reflux ratio is used for Ponchon Savorit method.
Explanation: Here the reflux ratio is based on the flow rates of the final plates of the enriching section or stripping section; so internal reflux ratio comes to the part.
3. Find the heat removed by the condenser if the net heat out of the condenser is 25000 J and the total moles are 25.
a) 1000 J
b) 10000 J
c) 5000 J
d) 2000 J
Explanation: Heat removed by the condenser = net heat out/ net moles out
= 25000 J/ 25
Explanation: X is the heat removed by the condenser where the net heat removed by the net moles out can be determined.
Explanation: Internal reflux ratio = 50/40 = 1.25.
Explanation: Heat removed by the condenser = Qc/D + Hd = 50/25 + 20 = 20 KJ/Kg.
Explanation: We have to calculate from n th tray
L*HL + G* Hg = DQ
Q=(50*20 + 40*10)/20 = 30 KJ.
8. The fictitious stream is the difference in the flow rates of the nth tray.
Explanation: Fictitious stream = Gn+1 – Ln (Represented by delta).
9. Ponchon Savorit method do not include enthalpy concentration diagram.
Explanation: The heat losses or heat used by the condenser or reboiler determined only by enthalpy concentration data.
10. Find the flow rate of liquid entering into the enriching section if the internal reflux ratio is 1.5 times min. Given minimum reflux ratio is 0.95 and the gas flow rate is 35 mol/hr.
a) 49.87 mol/hr
b) 22.167 mol/hr
c) 55.26 mol/hr
d) None of the mentioned
Explanation: Internal reflux ratio = Liquid flow rate/ gas flow rate ( in nth plate of section)
1.5 *0.95 = L/35
L= 49.87 mol/hr.
Sanfoundry Global Education & Learning Series – Mass Transfer.
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