Reference no: EM132329961

Assignment - Process control

PART A -

1. List any four objectives of process control.

2. Distinguish between continuous process and batch process.

3. Sketch the input - output characteristic of a single - speed floating controller.

4. Why derivative mode of control is not recommended for a noisy process?

5. Why is it necessary to choose controller settings that satisfy both gain margin and phase margin?

6. What is tuning a controller based on quarter - decay ratio?

7. Why are fuel and air sent at a specified ratio into a combustion chamber?

8. When is inferential control used?

9. What is meant by cavitations in a control valve?

10. What is "equal percentage" in the equal percentage valve?

PART B -

11 A process has two time-constants of 10 sec and 25 sec and a steady - state gain of 1.3. Find the gain of the proportional controller required to give a damping ratio of 0.5 in the closed loop response.

12. A) What are the situations under which an ON/OFF controller would provide satisfactory response?

B) A 5m diameter cylindrical tank is emptied by a constant outflow of 1.0m3/min. A two-position controller is used to open and close a fill valve with an open flow of 2.0m3/min. For level control the neutral zone is 1.0m [or hysteresis ±0.5m] and the set point is 12.0m. Sketch the level versus time and calculate the cycling period.

13. a) Explain the working of a pneumatic P+I controller.

b) A PI controller is reverse acting with PB = 20% and repeats per minute = 12 and derivative time 0.2 minutes. Determine the time at which the controller output reaches zero percent if the input error e_p to the controller varies e_p = 0.9t%, t ≥ 0 the controller output at t = 0 was72%.

14. a) i) Explain feed forward control with an example from distillation column.

ii) Describe split range control. Under what circumstances is it recommended?

14. b) i) Explain cascade control with a block diagram and example.

ii) Discuss the problems to be encountered while designing a controller for a multivariable control system.

15. a) i) Explain with a sketch the working of a pneumatic actuator with positioner.

ii) Discuss the factors to be considered before the selection of control valve for a given application.

15. b) i) Write down the flow equation of an equal percentage valve and sketch its inherent valve characteristic.

ii) Explain how you will practically determine the installed valve characteristic of a control valve in an installation and also the reasons for determining the installed characteristic.

iii) An equal percentage valve has a rangeability of 32. If the maximum flow rate is 100m3/hour, find the flow at 2/3 open setting.

Note - Need elaboratively as per the questionnaire and also, need the reference book from which they have taken these. Need the answers not from the web from the reference books with good clarification but with reference books names.