Process Calculations GATE-1997

Q 1: Pure carbon is completely burnt in oxygen. The flue gas analysis is 70 % CO₂, 20 % CO, and 10 % O₂. The percent excess oxygen used is

A) 20
B) 12.5
C) 0
D) 10

Show Answer

Q 2: The flowsheet is given below:

If the single pass conversion of A to B is 20 %, then the rate of recycle R (mol/h) is

A) 300
B) 400
C) 500
D) 600

Show Answer

Q 3: A feed at 1298 K, consisting of flue gas (CO₂, O_2, and N₂) and air, is passed through a bed of pure carbon. The reactions that occur both go to completion.

CO_2(g)+C(s)\rightarrow2CO(g),\;\triangle H_R^0\;at\;298\;K=170\frac{kJ}{mol}

O_2(g)+2C(s)\rightarrow2CO(g),\;\triangle H_R^0\;at\;298\;K=-220.4\frac{kJ}{mol}

The combustor is adiabatic and the product gases exit at 1298 K. Calculate the required moles of CO₂ per mole of O₂ in the feed stream, so that the net heat generated is zero and the bed temperature remains constant at 1298 K. Data: Mean molar heat capacities, C_Pm

Substance	C	O2	CO	CO2
CPm (kJ/mol.K)	0.02	0.03	0.03	0.05

Show Answer

Q 4: Sea water is desalinated by reverse osmosis as shown in the figure:

All compositions are on a mass basis. Calculate R/E.

Show Answer