Steel Finned Tube Heat Exchanger as Boiler Air Preheater

High-frequency welded steel finned tube air preheater is a key waste heat recovery heat exchanger widely installed at boiler tail flue. This finned tube heat exchanger recycles residual heat from high-temperature boiler flue gas to preheat combustion air before entering furnace, cuts coal/gas consumption, improves boiler combustion efficiency and reduces exhaust temperature. Designed with wear-resistant and anti-corrosion finned tube structure, our finned tube air preheater adapts to coal-fired, biomass, waste incineration and industrial gas boilers with dusty, sulfur-containing flue gas, serving energy-saving transformation for thermal power plants and industrial boiler projects worldwide.

Structure & Raw Material

Base Tube: Adopt 20G boiler seamless steel pipe, Q235B or ND anti-dew-point corrosion steel according to working conditions, high pressure & high temperature resistant, resist thermal fatigue from frequent boiler start-stop.

High Frequency Welded Steel Fins: Carbon steel strip fully welded on tube outer wall without gap, low thermal resistance. Heat exchange area is 4–7 times larger than bare pipe, greatly boosting heat transfer efficiency. Windward side installs anti-wear guard ring to avoid abrasion from ash-laden flue gas.

Air Header & Flue Shell: Thickened steel air collecting box ensures even air distribution; reinforced shell and support frame enhance whole-set rigidity against flue vibration.

Modular Layout: Custom single-row, double-row or multi-row tube bundle based on air volume and heat load, convenient for on-site installation inside boiler flue.

Working Principle of Finned Tube Air Preheater

High-temperature waste flue gas flows outside finned tubes and releases residual heat via convection heat transfer. Cold fresh combustion air flows inside base tubes or passes through tube gap in reverse flow, absorbing flue waste heat and turning into preheated hot air. Preheated air feeds into boiler furnace to support full fuel combustion, while cooled flue gas is delivered to dedusting system. Reverse flow design maximizes heat recovery rate and reduces heat loss of exhaust smoke.

Main Product Advantages

1. Outstanding Energy Saving & Higher Combustion Efficiency

Preheated air can raise furnace temperature significantly, promote complete fuel combustion, reduce incomplete combustion loss and cut fuel cost by 5%~12%. Effectively lower boiler exhaust temperature and improve overall thermal efficiency.

2. Wear & Corrosion Resistant for Complex Flue Gas

Integrated welded fins never drop off or loose; optional ND steel for low-temperature area prevents acid corrosion caused by sulfur condensate. Perfect for high-dust flue gas from biomass boiler and waste incinerator with long service life.

3. Compact Structure & Small Floor Space

Compared with traditional tubular air preheater, finned tube type features smaller overall size under identical heat exchange capacity, saving flue space and construction investment.

4. Stable Running & Low Maintenance Cost

Open fin gap design is convenient for regular soot blowing to clear ash accumulation on fin surface, avoid blockage and efficiency attenuation, reduce daily maintenance workload.

5. Wide Medium Compatibility

Fit hot flue gas vs cold air heat exchange, also available for waste gas heat recovery in chemical, metallurgy and cement industries.

Application Scope

Thermal power plant boiler flue gas air preheating system

Biomass boiler, MSW incineration boiler waste heat recovery preheater

Chemical plant, steel factory self-provided industrial boiler energy-saving retrofit

Gas boiler and waste heat boiler combustion air preheating equipment

Daily Maintenance Tips

Carry out regular steam or acoustic soot blowing to remove ash stuck on fin surface and keep stable heat exchange performance.

Periodically check tube welds and windward abrasion parts for air leakage or tube damage.

Monitor inlet & outlet temperature of flue and air to judge heat exchange efficiency in real time.

Keep exhaust temperature higher than acid dew point during low-load operation to slow down low-temperature corrosion.