CHE 4198 Lecture : Lecture 12
Document Summary
This lecture: gain insight into the dynamic behavior of, first-order processes, second-order processes, higher-order processes, time-delay processes, processes with inverse response. The process behavior depends on the selection of the input (of course! A number of standard types of input changes are widely used for two reasons: They are representative of the types of changes that occur in plants. Step input: example: reactor feedstock is suddenly switched from one supply to another, causing sudden changes in feed concentration, flow, etc. Ramp input: examples: gradual change in feed composition, heat exchanger fouling, catalyst activity, ambient temperature. Sinusoidal input: examples: 24 hour variations in cooling water temperature; Impulse input: examples: electrical noise spike in a thermo-couple reading; injection of a tracer dye. Input types: other types of input signals are also used, e. g. rectangular pulse, in process industries, the use of step-type input signals is most common, next: analysis of output responses to step- type inputs.
