CHE$-2\mathrm{.}4$: Process Dynamics Control

and: $3$ Hours

Max. Marks: $50$

$.4$ mple five questions in all, selecting atleast two questions from each Section. Assume

if oite data. if any, reasonably. Ask for the $x-x-x$

Section A

Explain the design equations for steady and dynamic feed forward controllers for a stirred tank heater and hence show that design of a feed forward controller arises directly from the model of a process. Also draw the bock diagram for dynamic feed forward temperature control of a stirred tank heater

Define Nyquist stability criterion and sketch the Nyquist plot for the system

$10$

with following transfer function: $G_{0L}(s)=\frac{100}{s+1}(0\mathrm{.}1s+10).$ Also determine

$10$

gain margin and phase margin from the Nyquist plot and comment on the sability of the system.

Design cascade controller using frequency response technique for the system

$10$

given below:

$G_{CS}=K_{CS},G_{PS}=\frac{2e^{-0\mathrm{.}5s}}{s+1},G_{CP}=K_{CP}(1+\frac{1}{{}_{t}s}),G_{PP}=\frac{2\mathrm{.}5e^{-1\mathrm{.}2s}}{4s+1}$

Neglect the dynamics of all other elements. The terms are having their usual meaning

IV Explain the following:

i$.$ Regeneration of catalytic reactor in regard with selective control systems

ii$.$ Feed back control system with large dead time

Section B

$$ A second order process and $($:$K_p=2\mathrm{.}5$