ABSTRACT
The commercially available CFD package, FLUENT was utilized to numerically solve the metal surface overheating issues of the reheater pendants that exist in the full-scale No.3 boiler of Dagang Power Station, Tianjing, China. Some factors that may affect the velocity and temperature distributions at the final reheater inlet section (final superheater outlet) had been taken into account when the designated coal was burned, such as the quantity and fashion of counter-flow in the operation, the pressure difference in the air box, and the downward inclination of the secondary air injection. The basic conclusion is that some corresponding measures must be taken to rebuild the flow constructions to effectively avoid the boiler reheater pendant metal overheating. To obtain background detail, eight reformation cases were arranged on the main field, influencing reasons to diagnose this boiler numerically. Compared to the base case, all of the reformation cases had some emendatory effects to the flow and temperature distributions. The most outstanding among the reformations was Case I, where the secondary air (OFA and the upper secondary air of primary air burner D) was operated with counter-flow with a downward angle, and the pressure difference in the air box was increased. It can then be concluded that Case I can more efficiently modify the velocity and temperature deviations in the overheating regions, to ensure the furnace will operate within stable and safe conditions. Undoubtedly, these conclusions are of value to the other units of this power plant, and to other power plant furnaces throughout China that have similar construction and capacity.
