Project ForgeMass Transfer
Mass Transfer Operations
GATE 2009
Medium
A flash distillation drum separates a methanol-water mixture. Feed mole fraction of methanol is 0.5, feed flow rate 1000 kmol/hr, distillate/feed ratio is 0.5. The equilibrium relation is y*=4x. The mole fraction of methanol in the distillate is
- A0.2
- B0.7
- 0.8
- D0.9
Explanation
With D/F=0.5, B/F=0.5. Overall balance: zF=0.5y+0.5x ⟹ 0.5=0.5(x+y) ⟹ x+y=1. Combined with equilibrium y=4x: x+4x=1 ⟹ x=0.2, y=4×0.2=0.8.
Source: GATE CH 2009 (2009)
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