Air Preheater Performance Analysis: Installation of Soft Seal Material to Improve Air Preheater Leakage

Air preheaters are used in thermal power plants to preheat combustion air before it enters the furnace by recovering and using waste heat from the flue gas that is supposed to be exhausted at the stack to reduce the work needed by the furnace to combust fuel and improve the boiler efficiency. Air preheater leakage is the bypassing of the cooler ambient air into the flue gas side, reducing the temperature needed to heat the heating elements which transfers the heat into the air side. This negatively impacts the heat transfer effectiveness of the air preheater and the overall thermal efficiency of the plant. This paper aims to review the effectiveness of the soft touch seals applied in a Ljungstrom Type Regenerative Air Preheater installed in a 455 MW (net) Coal-Fired Thermal Power Plant situated in Mauban, Quezon Province in the Philippines in reducing the air preheater leakage through calculations and analysis in compliance with the ASME Performance Test Code to ensure accuracy and repeatability.