High-Efficiency Finned Heat Exchanger for CO2 & Steam Cooling

This project involves the cooling of a high-temperature process gas mixture of CO₂ and steam, with extreme inlet temperature conditions and strict pressure drop limitations. The application requires a compact, robust, and corrosion-resistant finned heat exchanger capable of stable performance under thermal shock and continuous operation.

Operating Requirements

The finned heat exchanger is designed to meet the following process conditions:

• Gas inlet temperature: 1000°C

• Gas outlet temperature: 30°C

• Gas composition: CO₂ + Steam mixture

• Gas mass flow rate: 3 kg/min

• Cooling duty: 3 kW

• Maximum allowable pressure drop: < 50 mbar

These parameters place high demands on material selection, fin geometry, tube layout, and overall thermal design.

Heat Exchanger Design Concept

Based on thermal calculations and material performance at elevated temperatures, a high-temperature finned tube heat exchanger is selected. The design emphasizes:

• Maximum heat transfer efficiency

• Extremely low gas-side pressure drop

• Long-term resistance to oxidation and thermal fatigue

The exchanger uses 3/4 inch stainless steel tubes with integral stainless steel fins, optimized for gas-side convection while maintaining structural integrity at 1000°C.

Material Selection: SS310 Tubes and Fins

Stainless Steel 310 (SS310) is chosen for both tubes and fins due to its excellent high-temperature properties:

• Continuous oxidation resistance up to ~1100°C

• High chromium and nickel content for superior thermal stability

• Excellent resistance to carburization and steam oxidation

• Proven performance in furnace exhaust and high-temperature gas cooling

Using the same alloy for tubes and fins eliminates differential thermal expansion, improving mechanical reliability and fin bonding strength.

Thermal and Flow Performance

• High heat transfer efficiency: Optimized fin spacing and height enhance heat dissipation from the gas stream

• Low pressure drop: Large flow passages and smooth fin geometry ensure gas pressure drop remains below 50 mbar

• Stable cooling performance: Designed to handle wide temperature gradients without deformation

With a cooling duty of 3 kW, the exchanger efficiently reduces gas temperature from 1000°C to 30°C under the specified flow rate.

Mechanical Design Features

• 3/4 inch SS310 seamless tubes

• High-temperature SS310 fins (plain or serrated type)

• Welded tube-to-header construction for leak-free operation

• Rigid frame designed to accommodate thermal expansion

• Horizontal or vertical gas flow configuration available

Typical Applications

• Furnace exhaust gas cooling

• CO₂ recovery systems

• High-temperature process gas conditioning

• Energy recovery from hot process streams

• Pilot-scale and laboratory thermal systems

Advantages of This Solution

• Safe operation at extremely high inlet temperatures

• Minimal system backpressure

• Long service life under aggressive thermal conditions

• Compact footprint with high thermal efficiency

• Fully customizable for OEM and pilot projects

Conclusion

For applications requiring cooling of CO₂–steam mixtures from 1000°C to near-ambient temperatures with minimal pressure loss, a SS310 finned heat exchanger using 3/4 inch tubes and SS310 fins is a technically sound and reliable solution. The design meets all thermal, mechanical, and flow constraints while ensuring long-term operational stability.