📋 Case Study

Smart Control Valve Monitoring in LNG Liquefaction Train

Valve stiction causing oscillatory control and process instability; no visibility into actuator health or packing wear

🏗️ Project Overview

Deployment of smart positioners with valve diagnostics on critical J-T valves in Qatar LNG facility

🎯 Challenge

Valve stiction causing oscillatory control and process instability; no visibility into actuator health or packing wear

🔧 Design Approach

Installed digital positioners with friction, travel time, and step response analytics; integrated with Emerson DeltaV AMS for automated health reporting

📐 Design Diagram

AI-generated project design illustration

📐 Key Calculations

Stiction Index

ΔI / Δx × 100%

Result: 2.8%

Indicates acceptable friction (<3%)

Step Response Time

t_95% = 3·τ

Result: 1.8 s

Within spec for cascade control loop stability

📊 Results

Improved temperature control stability by ±0.3°C; avoided $2.1M/year in energy waste; achieved SIL 2 compliance via diagnostic coverage proof

💡 Lessons Learned

• •Step response must be validated under actual process pressure
• •Positioner firmware updates require full functional safety revalidation

✅ Key Takeaways

• 1Step response must be validated under actual process pressure
• 2Positioner firmware updates require full functional safety revalidation