1. Lecture 2: Process flows, problem- solving
Chemical engineering 170

2. We’re doing two things today!
Chemical Process Flows
Problem-Solving

3. Chemical processing
Chemical Process: a combination of steps in which starting materials are converted into desired products using equipment and conditions that facilitate that conversion.

4. Unit operations (Unit ops)
A unit operation is a basic piece of a chemical process.
When you chop a process into numbered steps, you are analyzing it as a series of unit ops.

5. Unit operations (Unit ops)
A unit operation is a basic piece of a chemical process.
When you chop a process into numbered steps, you are analyzing it as a series of unit ops.
series of unit ops.

6. Unit operations (Unit ops)
A unit operation is a basic piece of a chemical process.
When you chop a process into numbered steps, you are analyzing it as a series of unit ops.
Examples of unit operations:
Heating
Cooling
Mixing
Separation
Reactions

7. Block diagrams vs. process flow diagrams (PFDs)
Digestive System
Cardio-Pulmonary Bypass

8. Process Flow Diagram (PFD)

9. Process Flow Diagram (PFD)

10. Process Flow Diagram (PFD)

11. Process Flow Diagram (PFD)

12. Process Flow Diagram (PFD)

13. Example: Diagramming a process
Dioctyl phthalate (DOP) is a plasticizer, mixed into polymers to make them more flexible (think PVC-plastic raincoats). It is synthesized by mixing phthalic anhydride with an alcohol such as octanol.
DOP
phthalic anhydride
octanol

14. Example: Diagramming a process
Draw a block diagram describing the following process:
Pthalic anhydride and octanol are fed into a reactor. DOP flows out but is still mixed with leftover alcohol. This mixture flows into a distillation column to be separated by evaporating the alcohol. Pure DOP is released as the final product while the octanol is channeled into a cooler-condenser to be cooled back into a liquid. The liquid octanol is then fed back into the initial alcohol stream. Draw a block diagram describing this process.

15. Problem-Solving
“Problem-solving skills” can mean the skills needed to solve regular textbook problems.
Consider a simple physics problem:
A bouncing ball leaves the ground with a velocity of 4.36 m/s at an angle of 81 degrees above the horizontal. How long did it take the ball to land?
How would you go about solving this?

16. Problem-Solving
More complex “back-of-the-book” problems can be approached in similar ways:
Determine what information you have.
Determine which information you want in the end.
Figure out how to get from here to there, using the equations and relationships you have been taught.
These types of problems are important for teaching you science, how to do calculations and figure things out with math.
But most problems you will encounter as an engineer are:
Poorly defined
Open-ended.
What problem-solving skills help with this kind of problem?

17. Problem-solving Method
Define problem
List possible solutions
Evaluate and rank
Develop plan
Re-evaluate plan
Implement plan
Check Results

18. What’s the point of a “problem-solving method” anyway?

19. Metacognition Learn to think about your thinking!
“Studies confirm the role of metacognitive skills in facilitating problem solving in planning, monitoring, regulating, and orchestrating the processes to foster the resolution of the problem. Individuals with high metacognition are better problem solvers, regardless of age or aptitude. Research suggests that individuals’ problem solving benefits from instruction in metacognitive techniques.” – Improving Student Information Search: A Metacognitive Approach, Chapter 4, Blummer and Kenton, (2014) pp

20. Example: Defining the problem
What is problematic about this defintion?
What would you look at to better define the problem?
Your grandmother: “The Internet is broken.”

21. Example: Brainstorming
As an engineer working for a company that produces food products, you discover a byproduct from one of the company processes. The byproduct is mostly protein (it could be edible) and has the unusual ability to absorb large amounts of water so that it can swell up to 20 times its original volume. As a brainstorming exercise, list possible uses for this product that might become a basis for producing and marketing it.

22. Engineering design cycle
Another sort of “problem-solving method” focused on engineering design.

23. Failure! Failure is part of the engineering design cycle!
If we respond in the right way, it is a necessary and useful step in getting to success.
Possibly authentic quote

24. Failing Well
Final question for today: What can we do to make our failures useful?