Environmental Engineering Reference
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Level 5: Equipment design and engineering, enabling to achieve the established
processing targets, among others, by providing enough actuators for control.
Level 6: Design of safety,
information, and control systems to support plant
operations.
Level 7: Sensitivity analysis and optimization of sections of the process that have a
high impact on performance. This last step aims at correcting for any adverse effects
arising due to hierarchical sequential decision making.
7.5.5 Application of Generic Engineering Design Steps at Each Level
Per design level, the same typical sequence of design activities emerges:
a. Setting the scope of the design at this level by establishing:
￿
Functions and goals to be realized at this level
￿
The boundaries with boundary conditions
to achieve the design goal(s)
b. Collecting and assessing knowledge on existing designs and building blocks by
looking for patent information, empirical data, models, theory, and operational
experiences and identification of gaps in knowledge to be remedied with addi-
tional experimental programs
c. Synthesis of alternative structures by selecting, ordering, and connecting suit-
able building blocks at an appropriate scale to meet the goals targets set in the
scope step
d. Analysis of the physical behavior of the generated alternative structures by
means of model-based simulations, showing the flows of resources in these
structures
e. Evaluation of the performance of the alternative structures using as much as
possible quantitative metrics for SHEET
f. Selection of a few of the better alternatives as candidates for further elaboration
at the next lower design level
g. Documentation of the design decisions, rationales, models, and results in the
form of drawings and numerical data for transfer to the next level of design
￿
Suitable types of
building blocks
It is a current engineering design capability to integrate the activities in synthesis,
analysis, and evaluation steps in a systematic mathematical optimization format, pro-
vided that one has enough confidence in the process models (see Biegler et al., 1997).
The synthesis step gives rise to discrete decision variables, which define alternative
process structures (building blocks and connectivity), while continuous variables
relate to processing conditions, duties, and sizing. In the analysis step, the model equa-
tions can be rigorously set up, extended with inequalities delineating the domain in
which the model equations are valid. In the evaluation step, one can add a proper
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