Gas-Gas Heat Pipe Heat Exchanger for Boiler Waste Heat Recovery

Gas-Gas Heat Pipe Heat Exchanger for Boiler Waste Heat Recovery

Gas-to-Gas Heat Pipe Heat Exchanger Within the heat pipe heat exchanger, the heat pipes operate under vacuum conditions. The working fluid absorbs heat from high-temperature flue gas in the evaporation section and vaporizes into steam. Driven by pressure differential, the steam flows toward the condensation section. Upon encountering cooling in the condensation section, the steam condenses back into liquid while releasing heat, thereby heating the low-temperature air. The condensed liquid then returns to the evaporation section via gravity or a wick structure. This cycle repeats continuously, enabling heat transfer from flue gas to air.

Structural Features: Typically composed of a peripheral tube bundle and central partition, the partition separates the two-sided channels. Heat pipes are fully finned tubes, with individual pipes replaceable. This design allows flue gas and air to flow countercurrently within their respective channels, achieving highly efficient heat exchange.

High Heat Transfer Efficiency: The heat transfer efficiency of air-to-air heat pipe exchangers is 5-8 times that of conventional air preheaters, effectively recovering residual heat from boiler flue gases.

Facilitates Ash Removal: Flue gas heat exchange occurs outside the tubes, simplifying ash removal via methods like soot blowing and reducing the impact of ash buildup on heat transfer efficiency.

Easy Maintenance: Each heat pipe functions as an independent heat transfer element. Damage to a single pipe due to wear or corrosion has minimal impact on overall heat exchanger operation. Components are easily removable for maintenance and replacement.

Prevents Dew Point Corrosion: Through optimized design, the wall temperature of heat pipes can be adjusted to avoid the dew point temperature of flue gases. This effectively prevents dew point corrosion and extends equipment lifespan.

Application Results: For every 100°C increase in combustion air temperature, boiler thermal efficiency improves by 5%-8%. For example, preheating cold air from 20°C to 250°C can boost gas boiler efficiency from 90% to over 96%, yielding annual fuel savings of 10%-15%. Simultaneously, high-temperature combustion air promotes complete fuel combustion, reducing emissions of incomplete combustion byproducts like CO and hydrocarbons while lowering nitrogen oxide emissions by 15%-20%.