Temperature control of an exothermic chemical reaction taking place in a CSTR is done with the help of cooling water flowing in a jacket around the reactor. The types of valve and controller action to be recommended are________________?

Related Mcqs:

1. An ideal PID controller has the transfer function [1 + (1/0.55) + 0.25]. The frequency at which the magnitude ratio of the controller is 1, is________________?

   A. 0.5/0.2
   B. 0.2/0.5
   C. 0.2 × 0.5
   D. 1/√(0.2 × 0.5)

2. In a closed loop system, the process to be controlled is an integrating process with transfer function 1/2s. The controller proposed to be used in an integral controller with transfer function 1/T1s. When a step change in set point is applied to such a closed loop system, the controlled variable will exhibit__________________?

   A. Overdamped response
   B. Underdamped response
   C. Undamped response
   D. Unstable response

3. In an exothermic chemical reactor, the manipulated variable is the flow rate of_______________?

   A. Coolant
   B. Reactants
   C. Product
   D. None of these

4. Water is flowing through a series of four tanks and getting heated as shown in figure. It is desired to design a cascade control scheme for controlling the temperature of water leaving the tank 4 as there is a disturbance in the temperature of a second stream entering the tank 2. Select the best place to take the secondary measurement for the second loop?

   A. Tank 1
   B. Tank 2
   C. Tank 3
   D. Tank 4

5. Suppose that the gain, time constant and dead time of a process with the following transfer function: Gc(s) = 10 exp( – 0.1s)/(0.5s + 1) are known with a possible error of ± 20% of their values. The largest permissible gain Kc of a proportional controller needs to be calculated below taking the values of process gain, time constant and dead time as________________?

   A. 8, 0.6, 0.08
   B. 12, 0.6, 0.12
   C. 8, 0.6, 0.12
   D. 12, 0.4, 0.08

6. Water is entering a storage tank at a temperature T0 and flow rate Q0 and leaving at a flow rate Q and temperature T. There are negligible heat losses in the tank. The area of cross-section of the tank is A0. The model that describes the dynamic variation of temperature of water in the tank with time is given as________________?

   A. Q0(T0 – T) = Ac . h (dT/dt)
   B. Q0T0 – QT = Ac . h (dT/dt)
   C. Q(T0 – T) = Ac . h (dT/dt)
   D. Q(T0 – T) = Ac . (dTH/dt)

7. Temperature of molten pig iron (1450°C) and molten slag (1500°C) flowing out of a blast furnace is measured by a/an_______________?

   A. Chromel-alumel thermocouple
   B. Optical pyrometer
   C. Radiation pyrometer
   D. Either B. or C.

8. The offset introduced by proportional controller with gain Kc in response of first order system can be reduced by ____________________?

   A. Reducing value of Kc
   B. Introducing integral control
   C. Introducing derivative control
   D. None of the above

9. ______________ controller has the maximum stabilising time?

   A. P
   B. PD
   C. PI
   D. PID

10. The transfer function for a PID controller is (where, η i is the integral (reset) time and ηD is the derivative time.) ?

    A. Kc(1 + ηis + ηD ). s
    B. Kc[1 + (1/ηis) + ηD . s)
    C. Kc(1 + ηis + (1/ηD . s)
    D. None of these