CE 407 Separations

Registration number: 11618

Prerequisites: CE 304 (Chemical Engineering Thermodynamics), CE 318 (Transport Processes II)

Credits: 3

Instructor: Dr. David Courtemanche, 203A Furnas Hall, 645-3316, djcourte@buffalo.edu

Class Time: Lectures Online, links below.

Office hours: Mondays and Wednesdays at 11:00 am--12:00 pm EDT, Zoom Meeting Link: https://buffalo.zoom.us/j/4543279676?pwd=M0JHOUc4cW9kVWRKSS91ckduZ3VSdz09
or by arrangement (send email to arrange a meeting time), in 203A Furnas.

OPEN DOOR POLICY - djc will be happy to answer questions at ANY time; students should feel free email anytime with questions or to request a Zoom meeting

Course description: Staged operations of distillation, absorption, leaching, and extraction. Phase equilibria and application of equilibrium data to calculational methods provide knowledge of solution methods and limitations for binary and multicomponent systems.

Required textbook: McCabe WL, Smith JC, Harriott P. 2005. Unit Operations of Chemical Engineering, 7th ed. McGraw-Hill, New York. Denoted by "MSH" below.

Supplementary textbooks:
Treybal RE. 1981. Mass Transfer Operations, 3rd ed. McGraw-Hill, New York. Denoted by "T" below.
Dohert MF, Malone MF. 2001. Conceptual Design of Distillation Systems. McGraw-Hill, New York. Denoted by "DM" below.

Summaries of lectures, and materials pertaining to each, are posted here.

Lect. Date Description References
Text Notes
L01 7/11
Introduction to course. Introduction to textbook. Introduction to gas absorption. Rigorous calculation allowing for evaporation of liquid. Simplified calculation neglecting evaporation of liquid ("the usual approximations").
MSH pp. 521-525 Lecture 00
Lecture 01
Single-stage absorption
L02 7/12
Improving a gas absorption operating by adding stages; why countercurrent contact is best. Operating line, equilibrium curve, McCabe-Thiele diagram, counting of stages.
MSH pp. 643-653 Lecture 02
Countercurrent contact
Absorption tower example (everything except minimum liquid flow rate)
L03 7/13
Absorption factor method (Kremser equation). Absorption operations, including minimum liquid flow rate. Stripping operations, including minimum gas flow rate.
MSH pp. 653-660 Lecture 03
Absorption tower example (calculation of minimum liquid flow rate)
Stripping tower example
L04 7/14
Saturated vapor pressure and relative volatility. Binary vapor-liquid equilibria and phase diagrams.
MSH pp. 663-666, 737-742 Lecture 04
L05 7/15
Graphical method for binary flash distillation. Analytical method for binary and multicomponent flash distillation. Why a column improves product purities relative to flash distillation. Column mass balances. Percent recovery.
MSH pp. 666-681 Lecture 05
Binary distillation introduction
Binary distillation column flows exampleFlash distillation example
L06 7/18
McCabe-Thiele diagram: rectifying section operating line, feed line, stripping section operating line, counting of stages, feed stage location.
MSH pp. 681-694 Lecture 06
Binary distillation McCabe-Thiele method
Binary distillation tray efficiency (pp. 1-11)
Binary distillation McCabe-Thiele examples
Binary distillation McCabe Thiele 1925
Binary distillation Murphree 1925
Binary distillation further calcs and design (p. 1)
L07 7/19
Partial versus total condensers. Minimum number of stages, Fenske equation. Minimum and optimum reflux ratio. Use of overall and Murphree tray efficiency.
MSH pp. 674-675, 687-691,712-722 Lecture 07
Binary distillation McCabe-Thiele method (p. 6)
Binary distillation tray efficiency (p. 4)
Binary distillation further calcs and design (pp. 2-3, 5-6)
Binary distillation nearly pure products examples
Binary distillation enthalpy balance examples
L08 7/20
Nearly pure products: use of the Kremser equation for distillation. Enthalpy balance calculations: liquid and vapor mixture enthalpies.
MSH pp. 694-701 Lecture 08
Binary distillation McCabe-Thiele method (p. 6)
Binary distillation tray efficiency (p. 4)
Binary distillation further calcs and design (pp. 2-3, 5-6)
Binary distillation nearly pure products examples
Binary distillation enthalpy balance examples
L09 7/21
Enthalpy balance calculations: Condenser and reboiler duties. Design of columns: vapor pressure drop, downcomer level and tray spacing; flooding velocity and column diameter.
MSH pp. 701-712, 718-724 Lecture 09
Binary distillation tray efficiency (pp. 12-13)
Binary distillation further calcs and design (pp. 4-5, 7-11)
Binary distillation enthalpy balance examples
L10 7/22
Batch distillation.
MSH pp. 724-727 Lecture 10
Binary batch distillation theory
Binary batch distillation examples
L11 7/25
Introduction to multicomponent distillation: light and heavy keys, splits, non-distributed and distributed components, column sequencing. Short-cut methods: Fenske equation for minimum number of stages, Underwood's method for minimum reflux ratio, Gilliland correlation for number of ideal stages at operating reflux ratio.
MSH pp. 742-752, 757-759
DM pp. 144-145, 290-291
Lecture 11
L11 Example Problems
Multicomponent distillation column sequencing example
Multicomponent distillation short-cut examples
L12 7/26
Degrees of Freedom in a distillation process. Tray-to-tray calculations. Design versus performance models. Collection of VLE and LLE data!
MSH pp. 752-756
DM pp. 115-124, 144-145, 147
Lecture 12
Multicomponent distillation tray-to-tray examples
Multicomponent distillation performance models
VLE and LLE data DECHEMA series
L13 7/27
Definition of leaching, everyday example (making tea), theory for countercurrent contact. Problem-solving procedure, solved example problem.
MSH pp. 764-772 Lecture 13
Leaching example
Leaching example
Leaching more examples
Leaching shanks process
L14 7/28
Introduction to liquid extraction: basic process and uses, liquid-liquid equilibria, ternary phase diagrams, mass balances for a mixing step. Single-stage liquid extraction.
MSH pp. 772-783
T pp. 433-446
Lecture 14
Liquid extraction introduction
Liquid extraction single-stage examples
Video of Liquid extraction single-stage examples
L15 7/29
Multistage crosscurrent extraction. Multistage countercurrent extraction: overall mass balances.
MSH pp. 772-783
T pp. 446-448, 450-451
Lecture 15
Liquid extraction countercurrent examples (problems 1 and 2)
Video of Liquid Extraction Countercurrent Example
L16 8/01
Multistage countercurrent extraction: Hunter-Nash and McCabe-Thiele methods for counting stages.
MSH pp. 772-783
T pp. 450-453
Lecture 16
Liquid extraction countercurrent examples (problems 3(b), 4, 5(b) and 6)
Video of LLE Countercurrent Example 3b
L17 8/02
Multistage countercurrent extraction: minimum entering solvent flow rate. Liquid extraction equipment.
MSH pp. 783-789
T pp. 450-453
Lecture 17
Liquid extraction countercurrent examples (problems 3(a) and 5(a))
L18 8/03
Introduction to mass transfer: where mass transfer is "hidden" in tray towers. Estimation of liquid- and gas-phase diffusion coefficients. Solute flux: definition
MSH pp. 527-540, 542-543 Lecture 18
Appendix 19
L19 8/04
Solute flux through 1D slab for cases of equimolar counterdiffusion and one-component mass transfer (A diffusing through non-diffusing B). Film theory and mass transfer coefficients. Two Film theory introduction
MSH pp. 547-548, 555-556 Lecture 19
Exam 1 8/05
Covers Lectures 1-15, Homework 1-3
L20 8/08
Two-film theory: interfacial mole fractions yi and xi, overall mass transfer coefficients Ky and Kx. Correlations for mass transfer coefficients: dimensionless groups (Sherwood number Sh, Stanton number St, Colburn j factor for mass transfer jM), correlation equations for various flow situations. Theory of Murphree tray efficiency.
MSH pp. 576-585 Lecture 20
Mass transfer two-film theory examples
Mass transfer correlations
Mass transfer theory of Murphree tray efficiency
L21 8/09
Introduction to gas absorption with packed towers. Four alternate expressions for per-volume rate of mass transfer, integration of differential mass balance, height of transfer unit, number of transfer units.
MSH pp. 576-585 Lecture 21
Absorption packed towers introduction
Absorption packed towers example
Packed towers HTU (pp. 1-2, 5)
L22 8/10
Mass transfer correlations for heights of a transfer unit (HTU's) Hy and Hx (equations and example).
MSH pp. 576-585 Lecture 22
Packed towers HTU (pp. 3-4)
Packed towers mass transfer correlations
Table 18.1
Packed towers HTU example
L23 8/11
Types of packing. Hydraulics of packed towers: loading and flooding, correlations for pressure drop and flooding velocity. Determination of tower diameter based on operation at a fraction (typically 50-60%) of the flooding velocity, or at an appropriate specified pressure drop.
MSH pp. 565-575 Lecture 23
Packed towers pressure drop and flooding example
L24 8/12
Introduction to adsorption. Adsorption isotherms. Fixed beds: concentration profiles, mass transfer zone, break point and break-point time, breakthrough curve, length of unused bed.
MSH pp. 836-851 Lecture 24
Adsorption example
L25 8/15
More detailed look at adsorption: fundamental mass transfer equations. Adsorbent regeneration.
MSH pp. 836-851 Lecture 25
Adsorption example 2
L26 8/16
More advanced topics for packed towers: temperature effects, absorption from rich gases.
MSH pp. 586-589, 593-599 Lecture 26
Packed towers temperature effects example
Packed towers rich gases example
L27 8/17
Study Day
Exam 2 8/18
Covers Lectures 16-25, Homework 4-6

Learning outcomes: Click here for statement of learning outcomes

Composition of grade:
Homework 20%
Exam 01 40%
Exam 02 40%

Assignment of grade: Final grades for all students will be determined by establishing an optimal correlation between total points earned over the course (computed according to the preceding table and scaled from 0 to 1000; essentially continuously distributed data) and grade points (4.00 for A, 3.67 for A-, 3.33 for B+, ..., 1.33 for D+, 1.00 for D; quantized results). The highest reasonably achievable score (considered "perfect") and the lowest passing score will be set according to the instructor's judgment and experience maintaining consistency with past offerings of the course, and will typically be ~900 (90%) and ~300 (30%) respectively. An effort will be made to position grade lines at gaps in the distribution of course totals. Click here to see a hypothetical example of this procedure.

Professionalism: Students are expected to turn in homework that is neat, clear and well organized. Significant point penalties will be imposed for messy, disorganized, confusing or otherwise unclear work. Although allowances will be made for the effects of time pressure on exams, points will also be deducted for messy, disorganized, confusing or otherwise unclear solutions of exam problems.

Academic integrity: All students must fully familiarize themselves with University policy on academic integrity. Acceptable and unacceptable conduct will be reviewed on the first day of class. Acts of academic dishonesty, such as plagiarism or other infractions, will not be tolerated. As discussed on the first day of class, the concept of plagiarism applies not only to text per se, but also to mathematical derivations and computer programs. Students will be required to take responsibility for acts of academic dishonesty by bearing penalties resulting from these acts. Suspected instants of academic dishonesty will be investigated thoroughly in accordance with Steps 1-3 of the University’s Consultative Resolution process. If an act of academic dishonesty is substantiated, then a point penalty will be imposed at the first instance, and failure in the course will be imposed at any subsequent instance. Being allowed to continue the course with a point penalty is contingent on offering a reasonable explanation of the infraction. The instructor will be happy to answer questions about what does and does not constitute allowed behavior at any time. The instructors will cooperate fully with any investigation resulting from an appeal of a finding of academic dishonesty. Click here for examples of academically honest and dishonest behavior.

Reproduction of course material is prohibited without the author’s consent. Any student that posts any course materials without permission is violating the copyright.

Conduct: Students are required to treat all UB faculty, staff, visitors and fellow students with professionalism and respect. All students are expected to abide by the Obstruction or Disruption in the Classroom Policy. Any instance of disruptive, disrespectful or aggressive conduct in this course will result in the instructor following the steps outlined in this policy. Instructors will consult with the Department, the School, and the Office of Student Conduct and Advocacy as needed. The instructor will cooperate fully with any investigation or disciplinary process resulting from a violation of this policy or the campus Code of Conduct. Disrespectful, unprofessional or otherwise inappropriate conduct toward the instructor or a TA can result in a suspension of office hour privileges.

Accommodations for physical and learning disabilities: Students are encouraged to request reasonable accommodations for equal access to this course because of a physical or learning disability. To do so they must register with UB's Accessibility Resources Office (60 Capen Hall, 645-2608, http://www.buffalo.edu/studentlife/who-we-are/departments/accessibility.html). The instructors will fully support students in receiving approved accommodations, e.g., by bringing exams in advance to Accessibility Resources for students entitled to take exams there with extra time, or taking other actions requested the Office.

Support for victims of sexual violence: UB is committed to providing an environment free of all forms of discrimination and sexual harassment, including sexual assault, domestic and dating violence and stalking. If you have experienced gender-based violence (intimate partner violence, attempted or completed sexual assault, harassment, coercion, stalking, etc.), UB has resources to help. This includes academic accommodations, health and counseling services, housing accommodations, helping with legal protective orders, and assistance with reporting the incident to police or other UB officials if you so choose. Please be aware that in some situations, UB employees may be required reporters. This means that if you tell me about a situation, the information may need to be reported to the Office of Equity, Diversity and Inclusion. Regardless of whether the information must be reported, you will still have options about how the situation will be handled, including whether or not you wish to pursue a formal complaint. Please know that if you do not wish to have UB proceed with an investigation, your request will be honored unless UB's failure to act does not adequately mitigate the risk of harm to you or other members of the University community. You also have the option of speaking with trained counselors who can maintain complete confidentiality. UB’s Options for Confidentially Disclosing Sexual Violence provides a full explanation of the resources available, as well as contact information. You may call UB’s Office of Equity, Diversity and Inclusion at (716) 645-2266 for more information, and you have the option of calling that office anonymously if you would prefer not to disclose your identity. The instructors will fully support victims of sexual violence, e.g., by allowing extra time to turn in assignments, or making other accommodations in consultation with the Office of Equity, Diversity and Inclusion, and Counseling Services, in the interest of providing the best possible support and outcome for the student.

Grateful thanks to Johannes M. Nitsche for use of website and other course materials