Introduction
In chemical processing plants, butterfly valves are widely used for regulating and isolating fluid flow due to their compact design, quick operation, and cost efficiency. However, selecting the right butterfly valve for chemical service and installing it correctly are critical to ensuring safe and reliable operation. This guide outlines the selection criteria and installation steps tailored for chemical plant applications.
Part 1 – Butterfly Valve Selection in Chemical Plants
Identify the Medium
Determine the type of chemical (acid, alkali, solvent, slurry, etc.).
Check for corrosive, abrasive, or toxic properties that influence material selection.
Select the Valve Body Material
Cast Iron / Ductile Iron – Suitable for water-based, non-aggressive chemicals.
Stainless Steel (304/316) – Corrosion resistance for acidic or alkaline media.
PTFE-lined or FRP – For highly corrosive chemicals such as hydrochloric acid or sulfuric acid.
Choose the Disc and Seat Material
Stainless Steel Disc + EPDM Seat – For general chemical service.
PTFE Seat – For strong acids and solvents.
NBR Seat – For hydrocarbon or oil-based media.
Determine the Pressure and Temperature Rating
Verify the valve’s pressure class (PN10, PN16, Class 150, etc.).
Ensure the materials and seals can handle the operating temperature range.
Select the Operation Method
Manual Lever – For small sizes (≤ DN200).
Gear Operated – For larger sizes or higher torque requirements.
Pneumatic / Electric Actuator – For automated chemical process control.
Part 2 – Butterfly Valve Installation Process
Pre-Installation Checks
Inspect the valve for any damage, deformation, or foreign particles.
Verify nameplate data matches the pipeline specifications.
Pipeline Preparation
Ensure pipe ends are clean, smooth, and properly aligned.
Remove debris and flush the pipeline before installation.
Valve Positioning
Install the valve with the disc in the slightly open position to prevent seat damage.
For lined valves, avoid scratching the liner during installation.
Bolt Tightening
Tighten flange bolts evenly in a crisscross pattern.
Use the manufacturer’s recommended torque to avoid distortion.
Function Testing
Operate the valve fully open and closed to check for smooth movement.
Conduct a pressure/leak test before starting the system.
Commissioning
If using actuated valves, check limit switches, solenoid valves, and control wiring.
Confirm proper response to open/close signals in the chemical process control system.