📋 Case Study

Liquefied Natural Gas (LNG) Train Optimization

Excessive compressor power consumption and suboptimal refrigerant blend performance

🏗️ Project Overview

QatarEnergy North Field Expansion – 8 MTPA LNG train

🎯 Challenge

Excessive compressor power consumption and suboptimal refrigerant blend performance

🔧 Design Approach

Replaced propane–ethane–methane cascade with mixed-refrigerant (MR) cycle; re-optimized MR composition using PR-EOS phase envelopes

📐 Key Calculations

Dew/Bubble Point Envelope

PR-EOS with k₁₂ tuning

Result: −162°C @ 10 bar

Defines condensation/evaporation boundaries

Isentropic Compressor Efficiency

ηₛ = (h₂ₛ − h₁)/(h₂ − h₁)

Result: 78.5%

Directly impacts power draw

📊 Results

12% reduction in specific energy consumption, $28M/year OPEX savings, extended cold box life

💡 Lessons Learned

• •k₁₂ parameters must be regressed against experimental VLE data
• •MR composition sensitivity requires Monte Carlo uncertainty analysis

✅ Key Takeaways

• 1k₁₂ parameters must be regressed against experimental VLE data
• 2MR composition sensitivity requires Monte Carlo uncertainty analysis