The paper presents the results of model studies on the hydrodynamics of the world's first supercritical circulating fluidized bed boiler Lagisza 460 MWe, carried out on a scale model built in a scale of 1/20 while preserving the full geometrical similarity. To reflect the macroscopic pattern of flow in the boiler's combustion chamber, tests were carried out based on two dimensionless flow dynamic similarity criteria, while maintaining a constant Froude number value between the commercial and the scaled-down units. A mix of polydispersion solids with its fractional composition determined by scaling down the particle size distribution of the boiler's inert material was utilised for the tests using a special scaling function. The obtained results show very good agreement with the results of measurements taken on the Lagisza 460 MWe supercritical CFB boiler.
The article reports the results of measurements of the acoustic pressure of acoustic waves generated by acoustic dust cleaners mounted in the convection pass of the 670MWth Circulating Fluidised Bed boiler. Based on measurements carried out and the spectral analysis of recorded signals it was found that the level of acoustic pressure generated by acoustic cleaners for the frequency of 100 Hz was too low for the efficient cleaning of the heated surfaces of the reheater RH2 and superheater SH3.
The interrelation between fuzzy logic and cluster renewal approaches for heat transfer modeling in a circulating fluidized bed (CFB) has been established based on a local furnace data. The furnace data have been measured in a 1296 t/h CFB boiler with low level of flue gas recirculation. In the present study, the bed temperature and suspension density were treated as experimental variables along the furnace height. The measured bed temperature and suspension density were varied in the range of 1131–1156 K and 1.93–6.32 kg/m3, respectively. Using the heat transfer coefficient for commercial CFB combustor, two empirical heat transfer correlation were developed in terms of important operating parameters including bed temperature and also suspension density. The fuzzy logic results were found to be in good agreement with the corresponding experimental heat transfer data obtained based on cluster renewal approach. The predicted bed-to-wall heat transfer coefficient covered a range of 109–241 W/(m2K) and 111–240 W/(m2), for fuzzy logic and cluster renewal approach respectively. The divergence in calculated heat flux recovery along the furnace height between fuzzy logic and cluster renewal approach did not exceeded ±2%.