Final Exam Review
This Powerpoint is a list of what we
covered in Design I.
Anything from this coverage may be
on your final exam.
(Obviously, I will emphasize the
material after the mid-term exam in the
final exam.)
Exam Format
• Open Book
• Open Notes
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– Example of previous Final Exam in HW section of course website
• No solution is given
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Reminder of Course Grading and Final Schedule
Weekly Homework:
20%
Minor Design Reports
30%
Mid-Term Exam
20%
Final Exam
30%
– (Monday, December 12, 2011
8:00 – 10:00 am, in classroom)
Chapters 1, 2, and 3
• Chpt. 1&2 - The Design Process
– Ethics in Chemical Engineering
– Product design
• Chpt. 3 – Molecular Structure Design
– Property estimation
• Chpt. 4 – Process Creation
– Gross Profitability Analysis
– Process Synthesis
• Start with the reactor (differences in molecular type)
• Separation (differences in composition)
• Heat transfer, pumping, compression, flash tanks
(differences in temperature, pressure, and phase)
• Integraton
Chapters 4 and 5
• Chapter 5 – Simulation to Assist in
Process Creation
– Steady-state flow sheet simulation
• Table 5.1 – Unit Subroutines
• Recycle (tear streams)
– Recycle convergence
• Chapter 6 – Heuristics for Process
Synthesis
– Summary on page 174, Table 6.2
– Using these as a start in design/simulation
Chapter 7 – Reactor Design
• Reactor models
– PFR, CSTR, Equilibrium, Stoichiometric
– Custom made models
• CSTR & PFR
– Kinetics used to size the reactors
– Catalytic reactors
• Equilibrium reactors
– Temperature effects
• Heat effects
• Reactor Design for selective product
distribution
Chapter 8 - Separation
• Common separation methods
– Table 8.1 – p. 211
• Criteria for selection of a separation method
– Separation Factor (SF)
– Energy separation agent (ESA)
• Distillation
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Types: Tray vs. Packed towers
Reflux ratio
Equil. Trays
Column design
Design issues
Heuristics – page 161
Separation train synthesis - p. 219
– Mass separation agent (MSA)
• Needs a recycle loop
Chapter 18 – Heat Exchangers
• Heat duty
• Temperature driving force
• Type of equipment
– Shell and Tube
• Temperature driving force
– Correction factors (Figs. 18.14-16)
• Heat transfer coefficients and pressure drop
– Table 18.5 – Typical overall heat transfer coeff.
– Boiling HT ΔT = 45F for Nucleate Boiling, Fig 18.5
• Tube sheet layouts – Table 18.6, Figure 18.9
Chapter 19 – Separation Tower Design
• Distillation
– FUG method
– Plate efficiency
– Tower Diameter
– Pressure drop
• Absorption/Stripping
– Kremser method
– HETP values
– Tower Diameter
– Pressure drop
Chapter 20 – Pumps, Compressors, &
Expanders
• Pumps
– Various Types
• Compressors and Expanders
– Various Types
Chapter 22 - Costing
• Accounting
– Debits/credits; annual report; balance sheet
• Cost Indexes
• Capital investment costs (Table 22.32,pg. 591)
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Bare model costs, Table 22.11
Total depreciable capital
Total permanent investment
Total capital investment
• Estimation of Total Capital Investment
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Order-of-magnitude
Study estimate
Preliminary estimate
Definitive estimate
Chapter 22 - Costing
• Estimation of total capital
– Order-of-magnitude (method of Hill)
• See page 553, six tenths rule
• +/- 50%
– Study estimate (Method of Lang)
• See page 555
• +/- 35%
– Preliminary estimate (method of Guthrie)
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See page 557
+/- 20%
Most likely used for decisions
Need fob equipment purchase cost
Chapter 22 - Costing
• Purchase cost
– Pumps and Motors – Figs. 22.3-6
– Fans, Blowers, Compressors – Figs. 22.7-9
– Heat exchangers, Fired Heaters – Figs.
22.10-12
– Pressure vessels and Towers – Fig. 22.13
and equations for trays, etc.
– Other equipment
• See equations and Table 22.32, pg. 591-5
Chapter 23 – Profitability Analysis
• Total Production Cost – Table 23.1, p. 604
– C = COM + general expenses
– COM is sum of direct manufacturing costs plus
operating overhead plus fixed costs
– General expenses are selling, research, admin
cost, incentive pay Profit (gross earnings) or pretax earnings = S – C where S is annual sales
revenue
• Profit (gross earnings) or pre-tax earnings =
S – C where S is annual sales revenue
• Net earnings or profit = (1-t) gross earnings
where t = ~37%
Chapter 23 – Profitability Analysis
• Profitability Measures
– Return on Investment (ROI)
• Definition, pg. 602 Eq. 23.1 & pg. 616 Eq. 23.7
• ROI should be greater than commercial interest rate, I
• Moderate risk: ROI = 25%
– Payback Period (PBP)
• Time required for the annual earning to equal the original
investment, pg. 616 Eq. 23.8
• Low risk should be less than 2 yr.
• Simple replacement should be less than one year
– Venture Profit (VP)
• Annual earnings in excess of minimum acceptable return
on investment, pg. 617 Eq. 23.9
– Annualized Cost
• Sum of production cost and a reasonable return on the
capital investment, pg. 617 Eq. 23.10
Chapter 17 – Profitability Analysis
• Time value of money
– Table 23.6 – Single Payments
– Table 23.8 – Annuity Factors – Uniform
Series Payments
– Equal payments p times per year, interest
compounded m times per year, Eq. 23.29
p.623
– Equal payments p times per year,
continuous compounding interest, Eq.
23.31 p. 623
Chapter 23 – Profitability Analysis
• Time value of money
– Comparing equipment purchases
• Present worth, p 620
• Capitalized costs and perpetuities, p. 626-627
• Depreciation
– Straight line
– ACRS and MACRS
Chapter 23 - Profitability
• Rigorous methods
– Net Present Value (NPV)
• Cash flows are computed for each year of
projected life of the plant
– Investor’s rate of return (IRR)
• Interest rate where NPV is zero
The last 2 weeks
• Trouble Shooting
– Several Articles
Typical Economics Problem
• Problem 1
• You have determined that you will retired at 60 (assume you are
now 25!) and you want $90,000 a year until you are 80. How
much money must you invest with an effective interest rate of
8% per year? (HINT: First calculate the present worth of the
money needed and then calculate the annuity amount).
• Solution
• Funds needed from 60-80 years of age with annuity (A) of
$90K/yr (20 years). Use Eq. 17.32 with I = 0.08, n=20:
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P = A*{(1.08)^20 – 1}/(0.08*(1.08)^20)
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= $883,633
• You pay for 35 years; use Eq. 17.28:
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A = 883,633 * 0.08/{0.08*(1.08^35)}
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= $5130 per year
The End
• Have a Great Semester Break!
• Design II
– The challenges of putting a whole
chemical plant together and making it
operated efficiently.