Authors: H. Yin, D. Jin, J. Yan, X. Liu, M. Li, H. Wang
Year: 2025
Industry: Fossil Fuel Power Generation
Keywords: Use FSE, Dynamic, Boiler
ABSTRACT
Prediction of boiler tube temperature is of great significance for preventing tube overheating and ensuring safe operation of coal-fired boilers. Boiler tube temperature is affected by the highly uneven gas flow distribution in the furnace and steam flow distribution in boiler heat exchanger tubes. Additionally, the ash deposits on the outer surface and the oxide scale formed on the inner surface of tubes also strongly affect the tube temperature of boiler heat exchangers. However, so far there are few models that could consider all these key factors in the prediction of boiler tube temperature. This is primarily because there exists significant scale difference between the sizes of furnace and boiler tubes so that it is difficult to simulate the gas and steam flows in the same model framework. The present study overcomes this challenge and presents a comprehensive model incorporating all the above key factors in the prediction of boiler tube temperature. This model integrates a three-dimensional (3D) CFD model describing the gas flow and combustion processes in the furnace with a one-dimensional (1D) hydrodynamic model describing the steam flow in the tubes. The effects of ash deposits and oxide scale are incorporated into the 3D CFD model and 1D hydrodynamic model, respectively. This model is used to predict the tube temperature distribution of the platen superheater (PLSH) of a coal-fired boiler. The results demonstrate that tube overheating takes place at the tube areas where either the heat flux or the steam temperature is higher. Ash deposits reduce the heat flux and tube temperature of the PLSH at the heavily-deposited areas. Oxide scale growth due to tube overheating reduces the steam flow rate in the tubes, and thus, further increases the tube temperature. As a result, tube overheating and the resultant accelerated oxide scale growth form a mutually promoted cycle which greatly increases the tube overheating risk.