Question $2$

a$)$ Fig. $2\mathrm{.}0$ shows a single$-$loop feedback control strategy for ine parked bed reactor whose objective is the control of the product composition.

Figure $2\mathrm{.}0$ sing$-$loop feedback control

Various instruments are installed in the streams associated with the reactor to measure variables of interest in the respective streams.

i$)$ Identify, in general, the name of the instruments indicated by A$1,$ F$1,$ and T$1.[3$ marks$]$

ii$)$ Name the actual instruments that would be used as A$1,$ F$1$ and T$1.[3$ marks$]$

b$)$ Assess qualitatively the effectiveness of the control strategy $($Fig$.2\mathrm{.}0)$ in suppressing the effects of the following disturbances

i$)$ Increase or decrease in feed temperature, T$1.[4$ marks$]$

ii$)$ Increase or decrease in feed composition measured by A$2.[4$ marks$]$

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$1357ke.$

$2$

iii$)$ By considering the assessment in $($i$)$ and $($ii$),$ explain why loop enhancement using

feedforward would be used for the parked bed reactor. $[2$ marks$]$

iv$)$ Draw a feedback$/$feedforward strategy that will enhance the single$-$feedback loop in Fig$\mathrm{.}2\mathrm{.}0$ when feed composition fluctuates. $[4$ marks$]$