Page 358 - Analysis, Synthesis and Design of Chemical Processes, Third Edition

submitting your report. Consider two possible responses to this report.

1. Your boss accepts the report and notes that the report appears to be excellent and he or she
looks forward to reading it.
2. Your boss expresses concern and returns the report as before. In this case, you have a
reasoned response available. You show that your solution is consistent with the heuristic you
used to check your work. With this supporting evidence your boss would have to rethink his or
her response and provide you with an explanation regarding his or her concern.

In either case, your work will have made a good impression.

Guidelines and heuristics are frequently used to make quick estimates during meetings and conferences
and are valuable in refreshing one’s memory with important information.

11.1.2 Maximizing the Benefits Obtained from Experience

No printed article, lecture, or text is a substitute for the perceptions resulting from experience. An
engineer must be capable of transferring knowledge gained from one or more experiences to resolve
future problems successfully.

To benefit fully from experience, it is important to make a conscious effort to use each new experience to
build a foundation upon which to increase your ability to handle and to solve new problems.

An experienced engineer retains a body of information, made up largely of heuristics and
shortcut calculation methods, that is available to help solve new problems.

The process by which an engineer uses information and creates new heuristics consists of three steps.
These three steps are predict, authenticate, and reevaluate, and they form the basis of the PAR process.

The elements of this process are presented in Table 11.1, which illustrates the steps used in the PAR
process.

Table 11.1 PAR Process to Maximize Benefits of Experience: Predict, Authenticate, Reevaluate

1. Predict: This is a precondition of the PAR process. It represents your best prediction of the
solution. It often involves making assumptions and applying heuristics based on experience.
Calculations should be limited to back-of-the-envelope or shortcut techniques.
2. Authenticate/Analyze: In this step, you seek out equations and relationships, do research
relative to the problem, and perform the calculations that lead toward a solution. The ability to
carry out this activity provides a necessary but not sufficient condition to be an engineer. When
possible, information from actual operations is included in order to achieve the best possible
solution.
3. Reevaluate/Rethink: The best possible solution from Step 2 is compared with the predicted
solution in Step 1. When the prediction is not acceptable, it is necessary to correct the
reasoning that led to the poor prediction. It becomes necessary to remove, revise, and replace