CHE Problems
CHE656
Computer Applications for Chemical
Engineering Practice
Process Simulation with ASPEN PLUS
Exercise Problems
Version 2012
Prepared by
Dr. Hong-ming Ku
King Mongkut’s University of Technology Thonburi
Chemical Engineering Department
Chemical Engineering Practice School
© May 2004-2012 – Use with Permission of the Author Only
1
Section 1
Elementary Modules, Mass Balances, and Degree of
Freedom Analysis
2
1. Mass Balances and Constraints with Elementary Modules, I
Consider the following process which consists of a pump, a reactor, an absorber, and a distillation column. The feed consists of 2 chemical components, A and B, which are fed into the reactor in which the following reactions take place:
Reaction 1:
Reaction 2:
Reaction 3:
A + B
A
2C
→ C
→ D + 2E
→ D + F
Pure F
Pure E
S4
Components
A and B
S1
S7
S5
S2
Reactor
S6
Pump
S3
S8
Absorber
Distillation column
Pure liquid component E is fed into the absorber, in which all of component F in the absorber vapor feed S3 leaves the overhead while the rest of the components in stream S3 are absorbed (assume 100% absorption). Components A, B, C, D, and E are then separated by distillation (relative volatility is: C, D, A, B, E in decreasing order).
(a) Express the flowsheet above in terms of elementary modules. Note that except for mixers, only 1 inlet stream is allowed in all elementary modules.
(b) The following information is available about the process:
Reactor:
Outlet stream S3 contains 21.6 lbmol/hr of component F
The overall conversion of Reactions 1 and 2 based on A is 80%
Column specifications:
Light key = A
Heavy key = B
Mole-recovery of B in bottom = 98%
Process Feed:
Molar flow rate of A in feed = 100 lbmol/hr
Molar flow rate of B in feed = 150 lbmol/hr
Other information:
Mole fraction of A in column overhead = 24.06%
Total molar flow ratio of stream S5 to S4 = 9.26
3
Molar ratio of component
Computer Applications for Chemical
Engineering Practice
Process Simulation with ASPEN PLUS
Exercise Problems
Version 2012
Prepared by
Dr. Hong-ming Ku
King Mongkut’s University of Technology Thonburi
Chemical Engineering Department
Chemical Engineering Practice School
© May 2004-2012 – Use with Permission of the Author Only
1
Section 1
Elementary Modules, Mass Balances, and Degree of
Freedom Analysis
2
1. Mass Balances and Constraints with Elementary Modules, I
Consider the following process which consists of a pump, a reactor, an absorber, and a distillation column. The feed consists of 2 chemical components, A and B, which are fed into the reactor in which the following reactions take place:
Reaction 1:
Reaction 2:
Reaction 3:
A + B
A
2C
→ C
→ D + 2E
→ D + F
Pure F
Pure E
S4
Components
A and B
S1
S7
S5
S2
Reactor
S6
Pump
S3
S8
Absorber
Distillation column
Pure liquid component E is fed into the absorber, in which all of component F in the absorber vapor feed S3 leaves the overhead while the rest of the components in stream S3 are absorbed (assume 100% absorption). Components A, B, C, D, and E are then separated by distillation (relative volatility is: C, D, A, B, E in decreasing order).
(a) Express the flowsheet above in terms of elementary modules. Note that except for mixers, only 1 inlet stream is allowed in all elementary modules.
(b) The following information is available about the process:
Reactor:
Outlet stream S3 contains 21.6 lbmol/hr of component F
The overall conversion of Reactions 1 and 2 based on A is 80%
Column specifications:
Light key = A
Heavy key = B
Mole-recovery of B in bottom = 98%
Process Feed:
Molar flow rate of A in feed = 100 lbmol/hr
Molar flow rate of B in feed = 150 lbmol/hr
Other information:
Mole fraction of A in column overhead = 24.06%
Total molar flow ratio of stream S5 to S4 = 9.26
3
Molar ratio of component