Abstract for:Effects of leakage on air heater thermal performance

This paper outlines the approach that was used to develop a system dynamics model to evaluate the impact of air heater leakage on thermal performance of the secondary air heaters used at Eskom’s coal fired power stations. The simulator calculates oxygen leakage from the air side to the gas side of the air heater under normal boiler operating conditions.  In the absence of flue gas oxygen percentage at the air heater outlet, a different methodology was used to calculate leakage using temperatures and flow rates for air and gas. The leakage and thermal performance was compared to design specifications and the results show that the leakage at the current operations has increased by an average of 14.2% compared to design. The simulator was constructed based on generating unit 3 at the Majuba power station and ran at an hourly resolution for a time frame of one week. Although the research was incomplete at the time of the submission, the paper includes the model structure and interim results obtained using temperatures to calculate leakage.