QUESTION $3$

Consider a completely enclosed stirred$-$tank heating process is used to heat an incoming stream with flowrate $(w).$ The tank contents are well agitated and heated by an electrical heater that provides $Q$ watts. The heating rate from the coil and the volume $(V)$ were both constant.

Figure $2$: Continuous stirred tank reactor

$3\mathrm{.}1$ What is the control objective of the CSTR heater in Figure $2?$

$(2)$

$3\mathrm{.}2$ Identify the controlled variable, the manipulated variable and the disturbance.

$(3)$

$3\mathrm{.}3$ Suppose that the inlet temperature $T_i$ changes with time. Suggest and discuss five possible strategies that can be used to ensure that $T$ remains at or near the set point $T_a.$

$(15)$

$[20$ Marks$]$