G. Open-Ended Problems

The following are summaries for open-ended problems that have been used as term problems at the University of Michigan.

The complete problem statement of the problems can be found on the CRE Web site, Web Appendix G (http://www.umich.edu/~elements/6e/appendix/DVDROM-Appendix-G.pdf ).

G.1 ChemE Car

Each year, the finals of the Chem-E-Car competition is held at the annual meeting of the American Institute of Chemical Engineers (AIChE). To be able to compete in the finals, a student chapter must qualify at a regional competition, which is held in the spring. The competition is to design and build a small car that is powered by a chemical reaction, fits in no more than a very large shoebox, carries a specified amount of water (e.g., 500 dm3), travels a certain distance (e.g., 35 m), and stops. The amount of water to be carried and the distance are specified 1 hour before the competition begins. The complete list of rubrics can be found at https://www.aiche.org/chem-e-car-competitionr-rules.

G.2 Effective Lubricant Design

Lubricants used in car engines are formulated by blending a base oil with additives to yield a mixture with the desirable physical attributes. In this problem, students examine the degradation of lubricants by oxidation and design an improved lubricant system. The design should include the lubricant system’s physical and chemical characteristics, as well as an explanation as to how it is applied to automobiles. Focus: automotive industry, petroleum industry.

G.3 Peach Bottom Nuclear Reactor

The radioactive effluent stream from a newly constructed nuclear power plant must be made to conform with Nuclear Regulatory Commission standards. Students use chemical reaction engineering and creative problem solving to propose solutions for the treatment of the reactor effluent. Focus: problem analysis, safety, ethics.

G.4 Underground Wet Oxidation

You work for a specialty chemicals company that produces large amounts of aqueous waste. Your chief executive officer (CEO) read in a journal about an emerging technology for reducing hazardous waste, and you must evaluate the system and its feasibility. Focus: waste processing, environmental issues, ethics.

G.5 Hydrodesulfurization Reactor Design

Your supervisor at Kleen Petrochemical wishes to use a hydrodesulfurization reaction to produce ethylbenzene from a process waste stream. You have been assigned the task of designing a reactor for the hydrodesulfurization reaction. Focus: reactor design.

G.6 Continuous Bioprocessing

Most commercial bioreactions are carried out in batch reactors. The design of a continuous bioreactor is desired since it may prove to be more economically rewarding than batch processes. Most desirable is a reactor that can sustain cells that are suspended in the reactor while growth medium is fed in, without allowing the cells to exit the reactor. Focus: mixing modeling, separations, bioprocess kinetics, reactor design.

G.7 Methanol Synthesis

Kinetic models based on experimental data are being used increasingly in the chemical industry for the design of catalytic reactors. However, the modeling process itself can influence the final reactor design and its ultimate performance by incorporating different interpretations of experimental design into the basic kinetic models. In this problem, students are asked to develop kinetic modeling methods/approaches and apply them in the development of a model for the production of methanol from experimental data. Focus: kinetic modeling, reactor design.

G.8 Cajun Seafood Gumbo

Most gourmet foods are prepared by batch processes, that is, a batch reactor. In this problem, students are challenged to design a continuous process for the production of gourmet-quality Cajun seafood gumbo from an old family recipe. Some of the most difficult gourmet foods to prepare are Louisiana specialties, owing to the delicate balance between spices (hotness) and subtle flavors that must be achieved. In preparing Creole and Cajun food, certain flavors are released only by cooking some of the ingredients in hot oil for a period of time.

We shall focus on one specialty, Cajun seafood gumbo (http://umich.edu/~elements/6e/appendix/New_Orleans.pdf). Develop a continuous-flow reactor system that would produce 5 gal/h of a gourmet-quality seafood gumbo. Prepare a flow sheet of the entire operation. Outline certain experiments and areas of research that would be needed to ensure the success of your project. Discuss how you would begin to research these problems. Make a plan for any experiments to be carried out (see Chapter 7, R7.5, [http://www.umich.edu/~elements/6e/07chap/prof-7-5.html]).

Following is an old family formula for Cajun seafood gumbo for batch operation (10 quarts, serves 40):

1 cup flour

4 bay leaves, crushed

1½ cups olive oil

½ cup chopped parsley

1 cup chopped celery

3 large Idaho potatoes (diced)

2 large red onions (diced)

1 tablespoon ground pepper

5 qt fish stock

1 tablespoon tomato paste

6 lb fish (combination of cod, red snapper, monk fish, and halibut)

5 cloves garlic (diced)

½ tablespoon Tabasco sauce

12 oz crabmeat

1 bottle dry white wine

1 qt medium oysters

1 lb scallops

1 lb medium to large shrimp

  1. Make a roux (i.e., add 1 cup flour to 1 cup of boiling olive oil). Cook until dark brown. Add roux to fish stock.

  2. Cook chopped celery and onion in boiling olive oil until onion is translucent. Drain and add to fish stock.

  3. Add of the fish (2 lb) and of the crabmeat, liquor from oysters, bay leaves, parsley, potatoes, black pepper, tomato paste, garlic, Tabasco, and cup of the olive oil. Bring to a slow boil and cook 4 h, stirring intermittently.

  4. Add 1 qt cold water, remove from the stove, and refrigerate (at least 12 h) until 2 h before serving.

  5. Remove from refrigerator, add cup of the olive oil, wine, and scallops. Bring to a light boil, then simmer for 2 h. Add remaining fish (cut to bite size), crabmeat, and water to bring total volume to 10 qt. Simmer for 2 h, add shrimp, then 10 minutes later, add oysters and serve immediately.

G.9 Alcohol Metabolism

The purpose of this open-ended problem is for the students to apply their knowledge of reaction kinetics to the problem of modeling the metabolism of alcohol in humans. In addition, the students will present their findings in a poster session. The poster presentations will be designed to bring a greater awareness to the university community of the dangers associated with alcohol consumption.

Students should choose one of the following four major topics to further investigate:

  1. Death caused by acute alcohol overdose

  2. Long-term effects of alcohol

  3. Interactions of alcohol with common medications

  4. Factors affecting metabolism of alcohol

General information regarding each of these topics can be found on the CRE Web site.

The metabolism and model equations are given on the CRE Web site. One can load the Living Example problem for alcohol metabolism directly from the CRE Web site (http://www.umich.edu/~elements/6e/09chap/prof-pharmacokinetics.html).

G.10 Methanol Poisoning

The emergency room treatment for methanol poisoning is to inject ethanol intravenously to tie up the alcohol dehydrogenase enzyme so that methanol will not be converted to formic acid and formate, which cause blindness. The goal of this open-ended problem is to build on the physiological-based model for ethanol metabolism to predict the ethanol injection rate for methanol poisoning. One can find a start on this problem by the Professional Reference Shelf Material (http://www.umich.edu/~elements/6e/09chap/prof-pharmacokinetics.html) on Physiologically Based Pharmacokinetic (PBPK) Models in Chapter 9 that is on the Web.

G.11 Safety

As the chemical engineering profession continues to intensify its efforts on safety, examples of runaway reactions are analyzed in Chapter 13. A companion Web site on safety has been developed and can be found at (http://umich.edu/~safeche/). Each module contains the safety algorithm (shown in the following) that is to be filled out.

Safety Algorithm







Initiating Event:


Preventative Actions and Safeguards:


Contingency Plan/Mitigating Actions:


Lessons Learned:




The process or situation for which risk to people, property or the environment is being evaluated.


A chemical or physical characteristic that has the potential to cause damage to people, property or the environment.


What happened? Description of the event or sum of the events along with the steps that lead to one or more undesirable consequences, such as harm to people, damage to the property, to the environment, or asset/business losses.

Initiating Event:

The event that triggers the incident, (e.g. failure of equipment, instrumentation, human actions, flammable release, etc.). If necessary state precursor events, e.g. valve closed, inadvertent human action, nearby ignition source. The root cause of the sum events in causing the incident.

Preventative Actions and Safeguards:

Steps that can be taken to prevent the initiating event from occurring and becoming an incident that causes damage to people, property or the environment. Brainstorm all problems that could go wrong and then actions that could be taken to prevent them from occurring.

Contingency Plan/Mitigating Actions:

Steps that reduce or mitigate the incident after the preventative action fails and the initiating event occurred.

Lessons Learned:

What we have learned and can pass on to others that can prevent similar incidents from occurring

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