Final Exam ReviewThis 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 • Example of previous Final Exam in HW section of course website • No solution is given • 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 • 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) • Bare model costs, Table 22.11 • Total depreciable capital • Total permanent investment • Total capital investment • Estimation of Total Capital Investment • 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) • 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 pre-tax 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: • P = A*{(1.08)^20 – 1}/(0.08*(1.08)^20) • = $883,633 • You pay for 35 years; use Eq. 17.28: • A = 883,633 * 0.08/{0.08*(1.08^35)} • = $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.
