The cascade reactor control configuration shown in Fig. 16.3 utilizes a measurement of the cooling water temperature. It has been suggested that the temperature of the reactor wall be measured to deal with temperature gradients in the tank contents, a so-called triple cascade control loop. Draw a block diagram of the triple cascade control system, and discuss how this might provide an improved closed-loop response to a disturbance in cooling water flow rate.

Reactor Feed in temperature set point (master) TT -- TC Water surge tank i Jacket temperature ! set point (slave) LC --LT Reactor TT C Cooling water out Product Cooling water makeup Circulation pump Figure 16.3 Cascade control of an exothermic chemical reactor.