Heat Exchanger Tubes: 316Ti vs. 254 SMO Performance

 

Why 316Ti for cooling tower service?
Titanium stabilization prevents chloride stress cracking in 100 ppm Cl- water. Handles 70°C inlet temperature at 2.5 m/s flow velocity. Costs 40% less than super austenitics with 10-year service life.

 

When 254 SMO solves scaling problems?
For geothermal brine with 50,000 ppm TDS. 6.1% Mo content prevents under-deposit corrosion. Resists silica scaling adhesion better than standard grades. Maintains heat transfer coefficient >90% after 1 year.

 

Critical velocity limits?
Minimum: 1.2 m/s to prevent particulate settlement
Maximum: 3.0 m/s for 316Ti, 3.8 m/s for 254 SMO
Cavitation risk exceeds 6 m/s in any alloy

 

Tube-to-tubesheet joining methods?
Hydraulic expansion + seal welding for 316Ti
Explosive expansion only for 254 SMO (prevents work hardening cracks)
Avoid roller expansion in chloride service

 

Fouling monitoring techniques?
Thermal resistance calculation from ΔT/ΔP data. Ultrasonic thickness mapping under deposits. Infrared thermography identifying flow maldistribution.