CTH260S Tutorial 6
Question 1
The system acetone(1), acetonitrile(2), and nitromethane(3) at 80°C and 110 kPa has the
overall composition z1 = 0.45, z2 = 0.35, z3 = 0.20. Assuming that Raoult’s law is
appropriate to this system, determine, 𝐿𝐿, 𝑉𝑉 , 𝑥𝑥𝑖𝑖, and 𝑦𝑦𝑖𝑖
The vapor pressures of the pure species at 80°C are:
𝑃𝑃
1
𝑠𝑠𝑎𝑎𝑡𝑡 = 195.75, 𝑃𝑃2
𝑠𝑠𝑎𝑎𝑡𝑡 = 97.84 and 𝑃𝑃3
𝑠𝑠𝑎𝑎𝑡𝑡 = 50.32 kPa
Question 2
A compressed liquid feed stream containing an equimolar mixture of n-butane and
isobutane flows into a flash unit at flow rate F. At steady state, 40% of the feed stream is
vaporized and leaves the drum as a vapor stream with flow rate V. The rest leaves as
liquid with flow rate L. If the flash pressure is 1 bar, what is the temperature required?
What are the composition of the liquid and vapor exit streams?