π Case Study
Induction-Based Ethylene Cracker Tube Electrification (US Gulf Coast)
Thermal cycling fatigue limiting tube life to <2 years; flame impingement causing hot spots
ποΈ Project Overview
Replacement of fired tube bundles with high-frequency induction-heated alloy tubes in steam cracker convection section
π― Challenge
Thermal cycling fatigue limiting tube life to <2 years; flame impingement causing hot spots
π§ Design Approach
3-phase, 10 kHz induction coils wrapped around Incoloy 800H tubes with distributed fiber-optic temperature monitoring
π Design Diagram
AI-generated project design illustration
π Key Calculations
Skin Depth at 10 kHz
Ξ΄ = β(Ο/(Ο Γ f Γ ΞΌ))
Result: 2.1 mm
Validates coil placement for uniform heating
Tube Wall Temp Gradient
dT/dr = q'' / k
Result: 185 K/mm
Guided insulation thickness selection to limit outer wall temp to <450Β°C
π Results
Tube life extended to 5.3 years; cracking selectivity improved 3.2%; 100% elimination of combustion NOxπ‘ Lessons Learned
- β’High-frequency induction requires custom RF shielding to prevent interference with DCS radios
- β’Fiber-optic sensors must be installed pre-coil wrapping to avoid signal attenuation
β Key Takeaways
- 1High-frequency induction requires custom RF shielding to prevent interference with DCS radios
- 2Fiber-optic sensors must be installed pre-coil wrapping to avoid signal attenuation