Views: 0 Author: Site Editor Publish Time: 2025-12-18 Origin: Site
In industrial furnaces, boilers, dryers, incinerators, and CHP systems, flue gases leave the combustion chamber at high temperatures. A finned tube heat exchanger—often used as an economizer—transfers that waste heat to process water or boiler feedwater.
The fins significantly increase the heat-transfer surface area, allowing the exchanger to achieve higher thermal performance in a compact design.
System Application: Flue Gas at 280°C to 70–80°C
This heat exchanger is engineered to cool hot flue gas from 280°C down to 70–80°C, transferring up to 35 kWth into water. It is suitable for:
Gas-fired boilers
Biomass combustion
Waste incineration
Industrial ovens and drying systems
Thermal oxidation systems
SO₂ and SO₃ concentrations are considered in the design to avoid cold-end corrosion and ensure long service life.
Case Study: 35 kWth Finned Tube Economizer for Industrial Burner System
Background
A manufacturing plant operating a 500 kW gas-fired combustion system sought to improve energy efficiency by recovering heat from its 280°C flue gas stream. They required a compact economizer capable of delivering hot water for process use.
Challenges
Flue gas contained SO₂ (200 ppm) and SO₃ (8 ppm)
Required outlet flue gas temperature: 70–80°C
Pressure drop must stay within 700 Pa
Water pressure drop <40 kPa
System had limited installation space
Engineering Solution
A customized finned tube heat exchanger was built with:
Stainless steel 304 tubes + aluminum fins for maximum thermal performance
Optimized fin pitch to control fouling and limit pressure drop
Counterflow arrangement to achieve 35 kWth heat transfer
Corrosion-resistant coating on housing to handle acidic condensate
Oversized water channels to maintain <40 kPa pressure loss
Performance Results
Recovered heat: 35–38 kWth
Water temperature increased from 40°C to 60°C
Flue gas outlet: 76°C average
Annual fuel savings: 8–10%
Payback period: under 12 months
Customer Outcome
The plant significantly reduced energy consumption, improved emission performance, and gained stable hot-water output for operational processes without modifying its burner system.
Conclusion
A finned tube heat exchanger designed for flue gas–to–water heat recovery is an excellent solution for increasing energy efficiency in combustion systems. With proper material selection and engineering that respects SO₂/SO₃ corrosion risks and pressure-drop limitations, these exchangers offer long-term reliability, high performance, and rapid return on investment.
