Course Materials:

In addition to the design projects and the development of new senior level elective courses, part of this project is the development of short lectures, example problems and assigned problems that are appropriate for a variety of the standard required chemical engineering courses. The idea is that pollution prevention and subjects generally related to environmental concerns should be incorporated in a natural way throughout the curriculum. Presented in that fashion, these topics are seen by students as normal and expected applications of fundamental chemical engineering principles.

Adobe Acrobat (.pdf) files currently available can be viewed and obtained through the links below. Other modules will be added to this site as they are developed. If you do not currently have the capability to view PDF files, Acrobat Reader can be obtained by clicking below:

1. Tracking a pollutant -- an application of material balances

      A pollutant released to the environment works its way locally or globally through the Earth's major subsystems (the atmosphere, the lithosphere, and the hydrosphere). Questions of obvious importance arise. What is the time- and spatially-dependent history of a pollutant's concentration following its release? What steady-state level will it reach? Given certain corrective action, how long will it take to reduce the concentration to a safe level? Many such questions can be answered, at least in the form of useful estimates, by applying material balance concepts for the development of mathematical models of the physical system at hand. This module, which contains background information and four example/homework problems involving steady and unsteady material balances, is drawn from the case of polychlorinated biphenyls (PCBs) in the Great Lakes system -- a case that typifies environmental concerns and problems with persistent organic pollutants. CLICK HERE

 2. Material balances for the global carbon cycle

      Viewed in a global context, the Earth's natural processes are cyclic, embodying the principle of conservation of chemical elements. The study of these processes, termed "biogeochemical cycles", is the study of the transformation and transport of substances within and between the Earth's subsystems. An example of current interest and importance is the transformation and movement of carbon-containing compounds and the impact of human-caused disturbances. A major disturbance in the carbon cycle is the continuous injection of carbon dioxide into the atmosphere by the burning of fossil fuels. How much of this injected carbon ends up in the atmosphere? How much in the oceans? . . . in the land vegetation? What effect does the increase in carbon dioxide in the atmosphere have on the global climate? Insights to the answers to these and related questions can be gained through the use of mathematical models constructed by applying material and energy balance principles. This module contains an introduction to the modeling of biogeochemical cycles, with specific reference to the carbon cycle, including four example/homework problems, three on the application of steady and unsteady material balances and one on a global energy balance. CLICK HERE

3. Importance of mass transfer fluctuations on reaction outcome in multiphase reactors

This Mathematica notebook intended for use in reaction engineering, mass transfer or design classes. It solves the CSTR reaction equations for one, two and three phase reactions and shows how mass transfer rates, and fluctuations in mass transfer rates can change the product distribution for multiphase reactions.

Scale-up is a central issue for chemical engineers. It is discussed in transport, reaction engineering, separations and design classes, but usually in terms of quantitative aspects such as how big a reaction vessel needs to be to accommodate the required flow rates or how much packing is needed in an absorber. However, because of mass and heat transfer limitations with increasing size, the reaction products of multiphase reactions can change as the size of the reactor is increased. If only the conversion changes, there can be an increased need for separation "work" in the process. For consecutive or parallel reactions, different products may result that can be either of lower value or can be truly deleterious leading to a need for further processing to render these undesired products benign. For example, mass transfer limitations for an alcohol partial oxidation reaction to an aldehyde, can lead to formation of carbon dioxide which is worthless and/or formation of undesired organic acids. For any of these cases the result is increased waste and energy use, which have negative environmental impact.

This Mathematica notebook focuses on the effect that mass transfer rates have on reaction outcome. CSTR models are used for single phase, where there are no mass transfer effects, for liquid-solid systems and for gas-liquid-solid reaction systems. For liquid-solid systems mass transfer limitations (e.g., to/from the solid catalyst) can change the reaction outcome. The gas-liquid-solid reaction example is intended to model "trickle bed" (gas-liquid, cocurrent flow with a solid catalyst as a packed bed) reactors which can have strong "pulses" present. These pulses are disturbance waves that travel though the reactor causing periodic large increases in heat and mass transfer rates. Our research (Wu, McCready and Varma, Chemical Engineering Science, 50, pp3333-3334, 1995) has shown that periodic mass transfer fluctuations can lead to changes in selectivity that have a maximum at an intermediate frequency. Thus the possibility of "tuning" the (frequency of the pulses in the) reactor to make the best product distribution exists. The Mathematica notebook shows how to solve the coupled, transient CSTR equations and gives results showing the effect on reaction selectivity of fluctuations at different frequencies.

To view this notebook as an html file CLICK HERE. The html translation of the Mathematica notebook looses a lot, but gives an idea of the content.

To download the Mathematica notebook CLICK HERE.

If you don't have Mathematica you will not be able re-run the problems with different numbers or reaction mechanisms. However, if you want to download Math Reader CLICK HERE. You will be able to look at the examples and their solutions in complete detail.

4. Environmentally-Related Homework Problems for Core Chemical Engineering Courses

This is a collection of homework problems that are related to environmental issues and that involve core chemical engineering topics, including material and energy balances, heat transfer, reactor design, separations, and fluid flow.  A solution key is available.  CLICK HERE.