Comparative analysis of P/PI/PID controllers for pH neutralization process
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This document compares P, PI, and PID controllers for pH neutralization in a continuous stirred tank reactor (CSTR) system. It describes the pH system and different controller types. Simulations were conducted in MATLAB to analyze the response of each controller tuned using various methods. The PID controller tuned with the Tyreus-Luyben method performed best with minimum error indices and good stability and robustness in attaining the desired pH value without oscillations. The document concludes the PID controller is most suitable for controlling the pH neutralization process.
![Controllers
• P Controller
1. P controller produce an output signal proportional to the error.
2. P controller gives higher overshoot.
3. P controller shows higher settling time.
• PI Controller
1. PI controller consist proportional action and integral action of error.
2. PI Controller gives lower overshoot compare to P controller.
3. PI controller shows lower settling time compare to P controller.
• PID Controller
1. PID controller consist proportional, integral and derivative action of error.
2. PID controller gives lower overshoot.
3. PID controller shows lower settling time.
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Comparative analysis of P/PI/PID controllers for pH neutralization process
- 1. COMPARATIVE ANALYSIS OF P/PI/PID CONTROLLERS FOR pH NEUTRALIZATION PROCESS Paper I.D.-1027 Presented By, Chandra Shekhar (M.Tech Scholar) Supervised By, Mr. S.K. Sharma Asst. Professor Chemical Engineering Department Deenbandhu Chhotu Ram University of Science and Technology Murthal (Haryana) India
- 2. Content • pH systems • Controllers • Simulation • Response of P Controller • Response of PI Controller • Response of PID Controller • Conclusion • References
- 3. pH System • pH(Potential of Hydrogen) is a numeric scale used to specify the acidity and basicity of an aqueous solution. • It is approximately the negative of the base 10 logarithm of the molar concentration, measured in units of moles per liter, of hydrogen ions. • pH play an important role in waste water treatment plant of chemical, Pharmatutical industries etc. for discharging waste water in environment. • pH of waste water neutralize in system. • pH neutralization process in CSTR. • Digital pH measuring probe used to measure pH of the system. • HCL used to neutralize Alkaline water. • NaOH used to neutralize Acidic water. • Controllers designed in Neutral Region. • FOSPDT
- 4. Controllers • P Controller 1. P controller produce an output signal proportional to the error. 2. P controller gives higher overshoot. 3. P controller shows higher settling time. • PI Controller 1. PI controller consist proportional action and integral action of error. 2. PI Controller gives lower overshoot compare to P controller. 3. PI controller shows lower settling time compare to P controller. • PID Controller 1. PID controller consist proportional, integral and derivative action of error. 2. PID controller gives lower overshoot. 3. PID controller shows lower settling time. ( ) CG s K 1 ( ) [1 ]C I G s K s 1 ( ) [1 ]C D I G s K s s
- 5. Simulation • All simulations performed on MATLAB 4.0(control system design and simulation software) • Transfer function of CSTR neutralization process. • All simulation run at t=20, 100 sec. • Robustness Analysis. • Time domain Analysis. 0.5005 0.276 ( ) 3.2 1 s e G s s
- 6. Response of P Controller S.No. Method KC Robustness Analysis Time Domain Analysis IAE ISE ITAE Tr TS 1 Zeigler-Nichols 20.5 56.95 88.95 1316 2.27 9.25 2 Cohen-Coan 24.37 24.37 77.94 1136 1.9 11.25
- 7. Response of PI Controller S.No. Method KC Robustness Analysis Time Domain analysis IAE ISE ITAE Tr TS 1. Ziegler-Nichols 18.636 1.667 16.16 39.81 133.8 2.32 50 2. Cohen-Coan 21.15 1.2574 20.65 42.82 239.3 2.2 74.75 3. Tayrus-Luyben 12.8125 4.4 8.401 42.19 8.148 2.65 14.25 I
- 8. Response of PID Controller S.No. Method Robustness Analysis Time Domain Analysis IAE ISE ITAE Tr TS 1. Ziegler – Nichols 24.1176 1 0.25 27.32 44.87 539.1 2.06 84.75 2. Cohen-Coan 34.1018 1.1567 0.17697 33.7 75.33 557.4 1.85 83.75 3. Tayrus-Luyben 18.6364 4.4 0.3174 8.058 36.59 11.17 2.231 19.75 4. Marlin 2.355 1.38 1.1786 26.15 107.4 96.54 8 29.74 5. Smith et al. 2.316 1.3831 1.707 26.79 101.3 117.7 8 38.25 6. Branica et al. 2.66 1.8621 2.912 27.16 110.1 106.8 6.46 34.25 CK
- 9. Conclusion • P/PI/PID controllers are designed for pH neutralization system by different controller tuning methods. • All methods are worked in direction of settling the process variable to a desired set value. • In P controller IAE, ISE and ITAE are very minimum by Cohen and Coan method as compared to other controller tuning methods, this controller shows stability but not attained proper desired value. • In PI controller IAE, ISE and ITAE are very minimum by Tayrus and Luyben method as compared to other controller tuning methods, this controller shows stability but more oscillation in response to attain desired value. • In PID controller IAE, ISE and ITAE are very minimum by Tayrus and Luyben method as compared to other controller tuning methods. This controller shows good stability and robustness for the process without taking more oscillation to attain desired value.
- 10. References • Tyreus, B. D.; Luyben, W. L. Tuning PI controllers for integrator/dead time processes. Ind. Eng. Chem. Res. 1992, 2625−2628 • S.Sakthiya Ram, D. Dinesh Kumar and B.Meenakshipriya, Designing of PID controllers for pH Neutralization process, Indian Journal of Science and Technology, 2016;vol. 9(12). • Thomas E. Marlin, Designing Processes and Control System for Dynamic Performance; 2015; Edition 2nd, McGraw-Hill Inc. • Seborg, Edgar, Mellichap, Doyle, Process Dynamics and control; 2011; Edition 3rd page no. 223-225. • Donald R. Coughanour, Process System Analysis and Control; 1991; Edition 2nd page no. 54. • McAvoy TJ, Hsu E, Lowenthals S. Dynamics of pH in controlled stirred tank reactor. Industrial Engineering Chemistry Process Design and Development. 1972; 11(1):68–70. • O’Dwyer A. Handbook of PI and PID Controller Tuning Rules. 2006; 2nd edition, World Scientific Singapore.