Numerical Research of Deposits Formation and Influence on the Heat Transfer Process

Ash deposition on the heat transfer tubes in the heat recovery steam generator (HRSG) can pose a significant influence on the operating efficiency and operational safety. In this paper a numerical deposition model was developed to predict particle deposition/rebounding in the thermal boundary layer as well as the influence of physical properties of deposits on the heat transfer process. In addition, deposition rate, deposits distribution and variations of deposits with the running time were also predicted by numerical simulation method. Compared with the other 4 sub areas, a strong deposition tendency along the running time occurred in the HR3. The predictive results from the ash deposition model showed that the HRSG had a significant increase in average furnace temperature and outlet temperature, and a decline in overall heat transfer efficiency as the deposits initiated, grew and maturated. In general, the predicted results is in good agreement with the field measurements.