Question

Acetylene (C2H2), a gas used for welding, is converted into ethanol (C2H6O) and butanol C4H10O). A fresh feed of acetylene, H2, and O2 is combined with a recycle stream and is fed to a reactor where the following fractional conversions are achieved: acetylene conversion = 0.750, hydrogen conversion =0.900, and oxygen conversion =1.00. The reactor effluent contains the two products, unreacted components, and CO2 While the reactor effluent contains 1.10 moles CO2 per 1.00 moles ethanol, the stoichiometry of the reactions is unknown. The reactor effluent is sent to a separator where all of the CO2 leaves as a gas. The remaining components are sent to a second separation unit. The bottoms stre am of this unit contains all of the ethanol and butanol products. The process produces 140 mol/min of ethanol and 60.0 mol/min of butanol.

a. Draw and label a process flow diagram. Clearly number each stream.
b. Calculate the molar flow rates (mol/min) of each component exiting the reactor.
c. Calculate the molar flow rates (mol/min) of each component in the fresh feed.

Answer 1

Answer:

A) molar flow rates (mol/min) of each component exiting the reactor

E = 140 mol/min

B= 60 mol/min

A = 153.3 mol/min (.25 * 613.3)

H2 = 28.9 mol/min (0.1 * 288.9)

CO2 = 154 mol/min

B) the molar flow rates (mol/min) of each component in the fresh feed:

A in fresh feed = A in reactor + A in recycle

= 613.3 + 153.3 mol/min = 766.6 mol/min

H2 in fresh feed = H2 in reactor + H2 in recycle

288.9 + 28.9= 317.8 mol/min

CO2 = 154 mol/min (as 100% has been converted)

C) effect of purge stream on the overall conversion of acetylene

The purge stream will vent out a portion of H2 and C2H2 from the recycle stream, decreasing the total feed of H2 and C2H2 in the reactor. So the conversion will definitely decrease.

Explanation:

See attached pictures too.