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Recommendations
for case study reports for chemical engineering design courses
Final report: (See an example checklist
such as your instructor might use.)
·
Transmittal memo: Name
of company centered at top. On left
side: To (your imaginary boss, not the instructor), From
(you), Date, Subject. Indicate what
report is attached. Give conclusions and recommendations, with key information
such as annual production rates (in tonne or metric ton per year) of products
that meet specifications, fraction of primary feed component converted to
sellable products (overall conversion), total capital investment in $ million
(FCIL + L + WC), net present value in $ million, discounted rate of
return, discounted payback period, annual cost of manufacturing, critical
assumptions, concerns about potential safety or environmental problems, and
your recommendations on whether to build, not build, or improve the design of
the plant. Use 3 significant figures for
data. One page only. If the NPV is negative with the current
selling price of the product, instead of DCFRR give the minimum required
selling price, i.e. that which would give 0 NPV, and do not give DCFRR or
NPV. This is not the place to
tell all the things you tried; your boss wants to know your conclusions, not
what you did.
·
Summary: Title of report. “Summary” centered. Key information, probably close to what’s in the
transmittal memo.
The reason for duplicating the key information is that the transmittal
memo is likely to be separated from the report. Two pages max.
·
Contents: Use appropriate section headings with page numbers. (This requires that all pages be
numbered.) A separate page should be
used for figures and tables, with both numbers and titles of each given.
·
Body:
·
Appendices:
The appendices should enable
the reader to tell exactly how you arrived at the results summarized in the
body of the report, including the simulator’s pfd and stream table for your
optimal design, all calculations, and the sources of all data (see
References below). Provide sufficient information that the professor can
understand everything you’ve done.
A.
The pfd and
stream table from your simulator for your optimal design (only). Each stream should have both a name and a
number, and be arranged in ascending order.
B.
For each
piece of equipment in your optimal design, describe what it’s supposed to do,
its feed and product streams, and how you designed it in words, equations and
calculations (with numbers and units).
Include sizing, utility usage, costs, pressure drop, etc. Define symbols used in equations. Appropriate units must accompany all numbers
and conversion
factors must include units. If you
used a simulator for the calculations, list the specifications used for each
piece of equipment.
C.
For heat exchangers,
print out the temperature versus heat flow plots and the worksheets with T, P,
fraction vapor for each stream entering and leaving. Give your hand calculations of area,
including references for all sources of data.
D.
For reactors,
print out the results from your simulator.
For plug-flow and fluidized-bed reactors, print out the plots of
temperature, pressure, and the molar flow rate or mole fraction of each
component versus distance down the reactor.
Cite references by number for the sources of all data and computational
methods. Show your hand calculations for
the volume of the reactor, its heat transfer surface area, the pressure drop,
the amount of catalyst, the kinetics, etc.
E.
For strippers,
absorbers, distillation columns print out a plot of the mole fraction
of each component through the column.
Show your calculations for sizing and pressure drop, along with a
printout of the key sizing pages from your simulator.
F.
For pumps,
compressors and vessels show how each was sized and its utility requirement
determined. For motor size for a compressor, tell what efficiency you used and
cite the reference for the source of this efficiency. (The motor MUST have a larger power
requirement than the compressor.)
G.
Give
calculations for the following that are shown in CAPCOST: initial amount and
cost of an expensive material such as catalyst or extraction agent; annual makeup of this material; liquid and gas
waste disposal costs; credit for a waste stream burned as fuel.
H.
CAPCOST. Print each page except that giving the
constants for equipment costing.
·
References: Wherever information is given,
data are shown or a calculation method is used, cite a reference for the source
by number. That is, where did you get it? Examples would be reasons for choices of
materials of construction, U values for heat exchangers, and costs of
chemicals, utilities, and equipment.
These references should be listed by number on a page titled
“References” and not “Bibliography.”
Note that it is not sufficient to merely list these – they must be cited
in the text and in the appendices as they are used. For an article, include the authors' names,
article’s title, name of the magazine or journal, volume number, date, and
pages. For a book, include the author's
name, title, publisher, publisher’s city, date of publication, page numbers
used. Reference to a web site should
include the URL (address), title, and as much other information as you can
determine, such as the authors, the company or university, and the date it was
posted or updated.
·
Computer files:
Include a CD with all your computer files (e.g., Aspen Plus, HYSYS,
Excel, CAPCOST and Word) for your optimal design. Alternately, you can email these to the
instructor prior to submitting the final printed report.
·
Figures and tables: Each figure and table must be numbered
consecutively, have a caption telling what’s in it, and be referred to by
number and described in the text. This includes
stream tables and pfd's. Each should
appear immediately following the point where it is first referred to in the
text. Numbers and captions should be
above tables and below figures. The
general rule is that figures and tables should be understandable without
reading the text, and vice versa.
·
Presentation of
calculations Take care to define
all symbols and to explain each step of your calculations. If you wish to print out computations from
software such as MathCAD, MATLAB or Excel insert sufficient comments for each
step to be clear. If the same symbols
are used in more than one place, it may be more convenient to have a Table of
Nomenclature at the beginning of the report.
Some general rules are:
·
Significant figures: Use
the appropriate number of significant figures in the results in the body,
generally 3 and never more than 4. That includes tables. If you do not use CAPCOST, the Excel
spreadsheets for economics calculations should show numbers as $million. That is, for example, $1,523,489.56 should be
shown as $1.52 million. You can show
more significant figures in the appendices, but don’t be ridiculous. Plot results where possible, e.g. single-pass
conversion versus reactor P.
·
Process flow diagram and stream tables: The pfd and
stream table in the body of the report should be similar to those in the
appendices of Turton et al. Show the actual units and process streams,
not the artificial ones used in your computer modeling (such as mixers,
splitters, the bypass stream used to model a fluidized-bed
reactor, or the extra heat
exchanger used to model the situation when both phase change and
temperature change occur). This is most
easily done by using Microsoft Visio. Feed streams should enter at the left and
product streams exit at the right, and be clearly designated by names. Use both names and numbers for the feed
streams, the product streams, the waste streams, and the equipment. These should be in numerical order. The process stream and equipment designations
(names and numbers) should correspond to the tables summarizing the
details. The one table for the process
streams should give for each stream its temperature, pressure, fraction vapor,
total mass flow rate, total molar flow rate, molar flow rate of each component
present, and mass fractions in SI units.
The reader should not have to look at more than one table to get this
information for a process stream. The
streams should be in a logical order so that it is easy to locate a particular
stream. Use a reasonable number of
significant figures in decimal (not E) format.
·
Writing: The most important thing is that the reader
should have no doubt about what you mean, i.e. your writing must be clear and
understandable. Use precise and professional
technical language. Remember, to
be regarded as a professional engineer you must communicate in speaking and
writing as an educated engineer. Use Word’s spelling and grammar checker, but
don’t trust the spell checker for technical words – it may suggest a
non-technical word with a totally different meaning. Don’t use long and convoluted sentences. Take care using “which”; it always
refers to the immediately preceding word.
Take care in using “this” or “these” as it may leave the reader wondering
what you’re referring to. Use the past
tense only in describing what you’ve done, present in describing your results,
and future in talking about the plant to be built. Common spelling problems include the use of
"seperate" rather than
"separate," "it's" as a possessive, and “this data” or
“data is” rather than “these data” and “data are.” Remember, there is no "per" in
"separate" and that “data” is the plural form of the Latin noun
“datum.”
Oral report or exam:
·
Be
prepared to explain how you obtained all results; how all of the equipment
works; why you tried your various modifications to the base case; how your
process simulator and CAPCOST performed their calculations; the definitions of
all terminology (e.g., “discounted cash flow rate of return”); and safety,
health and environmental aspects of your design. When asked why you did something nutty, it is not acceptable to respond,
“the computer let me do it.” It is not acceptable to reply that "the
calculations wouldn't converge" when asked why you didn't make some rather
obvious improvement.
Remember, the objective is to impress your professor with
the quality, quantity, and creativity of your work.
___________________________________________________
Please email W. R. Wilcox with comments, suggestions, questions.. Last updated November 16, 2008.