1. for Chemical Engineering Calculations
Use of Spreadsheets
for Chemical Engineering Calculations
David E. Clough
Dept. of Chemical Engineering
University of Colorado
Boulder, CO USA
Gjesteprofessor ved NTNU
K4 – 229B
til

2. Fact: the spreadsheet program, and primarily
Microsoft Excel, is the most common computing
tool used by the practicing chemical engineer.
Other computing tools in common use:
Process simulator
[Aspen+, HYSYS, SimSci, ChemCAD]
Statistics
[SAS/JMP, SPSS, Statgraphics, …]
Programming & numerical methods
[Fortran 90, C/C++, Matlab, ...]

3. Types of ChE calculations carried out using Excel
General, small-scale, day-to-day calculations
formula-based calculations
data manipulation, graphics & statistics
what-if scenarios and case studies
Flowsheet calculations
material & energy balances
vapor-liquid equilibrium
chemical equilibrium & reaction kinetics
detailed design of process equipment
Financial calculations
project economics
profit/cost optimization

4. Problem-solving capabilities of Excel
Evaluation of engineering formulas
Data handling and graphics
Solution of algebraic equations
Solution of differential equations
Optimization calculations
Applied statistics
Advanced techniques
use of Visual Basic for Applications [VBA]
use of add-in products
[What’sBest!, DOEKISS, . . .]
communication with other programs
[HYSYS, LabView, . . .]

5. Spreadsheet Basics
Spreadsheet navigation
Creating formulas, using names
Copying and moving formulas
Using built-in functions
Creating graphs
Printing your work
Tutorial materials: CHAP1.PDF
all example spreadsheet files
and this presentation SPREADSHEETS.PDF
are on FagWeb for this course
Explanatory documents for all example
spreadsheet files available upon request

6. Example Problem: Felder & Rousseau, 4.6-5
Dehydrogenation of Propane
95% overall conversion
of propane
Separator produces 2 streams:
Product: H2, C3H6,
0.555% of C3H8 leaving reactor
Recycle: balance of unreacted C3H8
5% of C3H6 in Product stream
Reactor
Sep-
ara-
tor
Product
Recycle
Feed

7. Example spreadsheet files
FELDEREXAMPLE1.XLS
FELDEREXAMPLE2.XLS
Example from
Felder & Rousseau
SHIFT.XLS
water-gas shift reactor
solves nonlinear algebraic eqn
table-based case study with graphs
FSHT.XLS
flowsheet of process with recycle
automated convergence
cash flow analysis & optimization
TRIPLE.XLS
material & energy balances
interpolation of property tables
solution of linear alg equations
optimization of temperature drops

8. Example spreadsheet files
VLE.XLS
multicomponent VLE calculations
Wilson, NRTL and UNIQUAC models
FLASH.XLS
multicomponent flash calculation
NRTL model
VBA user-defined function
BATCH.XLS
batch reactor simulation
3 reactions, 6 components
compare to experimental data
nonlinear regression of
kinetic parameters

9. Example spreadsheet files
FIN.XLS
solution of PDE, heat conduction
surface plots for different materials
REACT.XLS
chemical equilibrium problem
7 nonlinear alg equations
solution using VBA macro
TANK.XLS
calibration of spherical tank
“live” bisection solution
table-based case study
user-defined function alternative
EVAL.XLS
ACETIC.XLS
project economics template
acetic acid plant example

10. References Walkenbach, Excel 2000 Bible, IDG Books, 99
Walkenbach, Excel 2000 Programming for
Dummies, IDG Books, 99
Walkenbach, Excel 2000 Power Programming
with VBA, IDG Books, 99
Gottfried, Spreadsheet Tools for Engineers,
Excel 97 Version, McGraw-Hill, 98
Jacobson, Excel 2000 Visual Basic for
Applications, Fundamentals, Microsoft Press, 99