ValveSizing 2134 ValveSizing 2134 ValveSizing 2134.pptx

ValveSizing 2134ValveSizing 2134ValveSizing 2134ValveSizing 2134ValveSizing 2134ValveSizing 2134ValveSizing 2134ValveSizing 2134ValveSizing 2134ValveSizing 2134

1. Presentation on Control Valve Sizing and Selection Course: Process Control Control valve receives a signal from controller (PLC/DCS) in order to operate The controller compares actual flow rate and desired flow rate Controller produce analog value to move the valve to maintain the set value

2. Contents Introduction Inherent and Installed Characteristics of Valve Valve sizing of control valves Selection of control valve 12 October 2024 2

3. Introduction Control valve receives a signal from controller (PLC/DCS) in order to operate The controller compares actual flow rate and desired flow rate Controller produce analog value to move the valve to maintain the set value 12 October 2024 3

4. 10/12/2024 Cross section of Control Valve

5. Characteristics 10/12/2024

6. Characteristics 10/12/2024

7. 12-Oct-24 Flow coefficient CV Flow rate in US gallons of water per minute at 60-degree F with pressure drop of psi across valve. Flow coefficient KV Flow rate in meter c ube per hour with pressure drop of 1 bar across the valve

8. 12-Oct-24 Calculation of FP factor

9. 12-Oct-24 Calculation of FP factor

10. 10/12/2024 Control valve sizing Calculation

11. 10/12/2024 Typical data sheet for valve sizing Calculation

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14. 10/12/2024 Selection of control valves Control valve is also known as final control element in process control Helps to control manipulated variable in PID loop Helps to make attain manipulated variable to its set value Ideal control valve Ideally Control valve must follow the PID output. Without lead or lag error Opening ranges: 100% to 100% or 0% to 0% Selection of control valve: Synchronizing the need of control loop with CV is called selection of control valve

15. 10/12/2024 Selection of control valve: Synchronizing the need of control loop with CV is called selection of control valve Under sized: Cannot provide sufficient flow margin to control sudden disturbances as it is already at 80% Rightly sized: Operating control valve setting is at 50% Upper and lower margin is 20% to 80% Over sized: As valve setting at 20% flow increases rapidly even for small disturbances. So, process goes to unstable.

16. 10/12/2024 Criteria for Selection of control valve: Criteria 1: Know the normal flow when the plant runs at its capacity This gives control valve capacity(CV) in gallon/min

17. 10/12/2024 Criteria for Selection of control valve: Criteria 2: Valve characteristics decides the pattern of flow rate with valve trim. Criteria 3: Selection of plug seat material as per the fluid media. Criteria 4: Selection of actuator compatible with valve.

18. Thank you 12 October 2024 18