(3) Chemical Equilibrium (30 pts)

1 mol/s of a species A is fed into a continuous gas phase reactor. The following two fast

equilibrium reactions take place in the reactor, which operates at 298 K and a pressure P:

A

B + C + D

Ka,R1 = 0.375 atm²

A+B= E + C

Ka, R2 = 3

The output of the reactor is assumed to be at equilibrium. The selectivity of the desired product

D with respect to the undesired product E (SD/E) is 2:1.

Organize

(a)

(b)

Analyze

(c)

Solve

R1:

(d)

(e)

R2:

Draw a process flow diagram and label all stream and system variables. (4 pts)

Write down three auxiliary equations in terms of the variables you wrote down in

your process flow diagram only. (6 pts)

Perform DOF analysis using the table on the right (3 pts)

Reactor

IstrV

"

IsysV

#Vars

SF+SC

Specified

System

vars.

AUX

MB

DOF

Write down all material balances, including the total material balance. (12 pts)

Solve to determine the fractional selectivity for the formation of D from A (3 pts)

(f) Determine the reactor pressure P (2 pts)