# Top-rated ScreenCasts

Text Section | Link to original post | Rating (out of 100) | Number of votes | Copy of rated post |
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01.6 Summary | Click here. | 100 | 1 |
Keys to the Kingdom of Chemical Engineering (uakron.edu, 11min) Sometimes it helps to reduce a subject to its simplest key elements in order to "see the forest instead of the trees." In this presentation, the entire subject of Chemical Engineering is reduced to three key elements: sizing a reactor (Uakron.edu, 7min), sizing a distillation column (uakron.edu, 9min), and sizing a heat exchanger (uakron.edu, 9min). In principle, these elements involve the independent subjects of kinetics, thermodynamics, and transport phenomena. In reality, each element involves thermodynamics to some extent. Distillation involves thermodynamics in the most obvious way because relative volatility and activity coefficients are rarely discussed in a kinetics or transport course. In kinetics, however, the rate of reaction depends on the partial pressures of the reactants and their nearness to the equilibrium concentrations, which are thermodynamical quantities. In heat exchangers, the heat transfer coefficient is important, but we also need to know the temperatures for the source and sink of the heat transfer; these temperatures are often dictated by thermodynamical constraints like the boiling temperature or boiler temperature required to run a Rankine cycle (cf. Chapter 5). In case you are wondering about the subject of " If you would like a little more practice with reactor mass balances and partial pressure, more screencasts are available from LearnChemE.com, MichiganTech, and popular chemistry websites. |

05.4 - Refrigeration | Click here. | 100 | 2 |
Refrigeration Cycle Introduction (LearnChemE.com, 3min) explains each step in an ordinary vapor compression (OVC) refrigeration cycle and the energy balance for the step. You might also enjoy the more classical introduction (USAF, 11min) representing your tax dollars at work. The musical introduction is quite impressive and several common misconceptions are addressed near the end of the video. |

14.09 - Numerical procedures for binary, ternary LLE | Click here. | 100 | 1 |
LLE flash using Matlab/Chap14/LLEflash.m (5:54) (msu.edu) An overview of the LLE flash routine in Matlab, including an overview of the program logic and then an example of how to run the program. See also - Supplement on Iteration of LLE with Excel and Matlab. |

10.02 - Vapor-Liquid Equilibrium (VLE) Calculations | Click here. | 100 | 2 |
VLE Routines - General Strategies (4:49) (msu.edu) Deciding which routine to use is more challenging than it appears. Also understanding the strategy used to solve the problems is extremely helpful in being able to develop the equations to solve instead of trying to memorize them. |

10.08 - Concepts for Generalized Phase Equilibria | Click here. | 100 | 1 |
Concepts for General Phase Equilibria (12:33) (msu.edu) The calculus used in Chapter 6 needs to be generalized to add composition dependence. Also, we introduce partial molar properties and composition derivatives that are not partial molar properties. We introduce chemical potential These concepts are used to show that the chemical potentials and component fugacities are used as criteria for phase equilibria. |

08.07 - Implementation of Departure Functions | Click here. | 100 | 2 |
Derive the internal energy departure function (uakron.edu, 20min) for the following EOS: Comprehension: Given ( /_{TV}RT = -2ln(1-η) - 16.49_{P}η/[1-_{P}βεβε(1-2η)/(1+2_{P}η)^2 ]_{P}1. Derive the internal energy departure function. 2. Derive the expression for the compressibility factor. 3. Solve the EOS for Zc. |

12.04 - The Flory-Huggins Model | Click here. | 100 | 3 |
The Flory and Flory-Huggins Models (7:05) (msu.edu) Flory recognized the importance of molecular size on entropy, and the Flory equation is an important building block for many equations in Chapter 13. Flory introduced the importance of free volume. The Flory-Huggins model combines the Flory equation with the Scatchard-Hildebrand model using the degree of polymerization and the parameter χ. The Flory-Huggins model is used widely in the polymer industry. Comprehension Questions: Assume δ for polystyrene, where _{S}δ is the solubility parameter for styrene. Also, polystyrene typically has a molecular weight of about 15,000. Room temperature is 25°C._{S}1. Estimate the infinite dilution activity coefficient of styrene in polystyrene. |

05.2 - The Rankine cycle | Click here. | 100 | 1 |
Rankine Cycle Introduction (LearnChemE.com, 4min) The Carnot cycle becomes impractical for common large scale application, primarily because H2O is the most convenient working fluid for such a process. When working with H2O, an isentropic turbine could easily take you from a superheated region to a low quality steam condition, essentially forming large rain drops. To understand how this might be undesirable, imagine yourself riding through a heavy rain storm at 60 mph with your head outside the window. Now imagine doing it 24/7/365 for 10 years; that's how long a high-precision, maximally efficient turbine should operate to recover its price of investment. Next you might ask why not use a different working fluid that does not condense, like air or CO2. The main problem is that the heat transfer coefficients of gases like these are about 40 times smaller that those for boiling and condensing H2O. That means that the heat exchangers would need to be roughly 40 times larger. As it is now, the cooling tower of a nuclear power plant is the main thing that you see on the horizon when approaching from far away. If that heat exchanger was 40 times larger... that would be large. And then we would need a similar one for the nuclear core. Power cycles based on heating gases do exist, but they are for relatively small power generators. |

14.10 Solid-liquid Equilibria | Click here. | 100 | 3 |
Solid-liquid Equilibria using Excel (7:38min, msu) The strategy for solving SLE is discussed and an example generating a couple points from Figure 14.12 of the text are performed. Most of the concepts are not unique to UNIFAC or Excel. This screeencast shows how to use the solver tool to find solubility at at given temperature. |

07.06 Solving The Cubic EOS for Z | Click here. | 100 | 2 |
6. Solving for density (uakron.edu, 9min) An alternative to solving directly for Comprehension Questions: 1. Solve for the liquid density (mol/cm3) of n-pentane at 62C and 2.5 bars using the vdW EOS. |