EXPERIMENTAL STUDY ON HEAT TRANSFER IN A ROLLING ASH COOLER USED IN THE CFB BOILER

摘要

From the view of the reliability and the techno-economy, the rolling ash cooler is feasible for the large-scale CFB boilers. However, existing studies on heat transfer in rolling ash cooler mainly focused on heat balance calculation and cold, hot test on the ash cooler outputs. In the heat balance calculation, the value of the overall heat transfer coefficient (α) is usually estimated by the experience, lacking of the support of experimental data. In this paper, a dynamic experimental system was built to measure the overall αin the rolling ash cooler and the influencing factors, including ash size, ash amount and rotational speed, using the orthogonal design. The results showed that the ash size has the greatest effect on α, and rotating speed has the least. The heat transfer in rolling ash cooler could be enhanced by increasing the rotating speed and decreasing the ash size. The αincreased with ash amount when the ash amount is small, but keep nearly constant when ash amount exceeds a certain value.