1. Carbon monoxide and hydrogen react to form methanol. A fresh feed containing the reactants joins a
recycle stream and the combined stream flows to the reactor. The reactor outlet stream is 350 mol/min
with wt %’s of 10.6 H2, 64 CO and 25.4 CH3OH. This stream enters a condenser where most of the
methanol is condensed and withdrawn as a product stream. The gas stream leaving the condenser,
which contains CO, H2 and 0.40 mole % methanol vapor, makes up the recycle stream. (30 pts)
Find the following USING ATOMIC SPECIES BALANCES:
a) molar flow rates of CO and H2 in the fresh feed
b) production rate of liquid methanol
c) single-pass and overall conversion of CO
n6 (CH3OH), n5 (CO), n4 (H2)
350 mol/min
n1(CO), n2 (H2)
.095 CH3OH np (CH3OH)
.274 CO
.631 H2
Find mole %’s : 6 pts
DOF analysis:
Overall: 3 unknowns, only 2 independent atomic balances
Condenser: 4 unknowns, 3 species, 1 piece of info (mole fraction of CH3OH)
Around condenser:
n4 = .631* 350 = 222 (2 pts)
n5 = .274 * 350 = 94.5 (2 pts)
.004 = n6/(222 + 94.5 + n6) n6 = 1.28 (3 pts)
np = 350 – 222 – 94.5 – 1.28 = 32.2 moles (2 pts)
Overall atomic species balance to find n1 and n2:
C: n1 = np = 32.2 (2 pts)
H: 2n2 = 4nPn2 = 64.4 (2 pts)
Mixing point balance to find CO to reactor: n1 + n5 = 126.7 (3 pts)
