パイロット試験で採取されたセラミックフィルター集塵灰の物性評価

抄録

To understand agglomeration phenomena of ash particles in a hot gas ceramic filter system, actual tests were carried out on candle filters with a 4MWth pressurized internally circulating fluidized bed boiler (PICFB) pilot plant. Coal ashes build up on the ceramic filters were analyzed by computer controlled scanning electron microscopy (CCSEM) and thermo- mechanical analyzer (TMA). The dust cake taken at 800°C did not show any sign of bridging or cleaning difficulty, while those at 950°C showed some difficulty in cleaning because of ash bridging between the adjacent ceramic filters. The initial deformation temperatures of the non-bridge dust were about 800°C. The index of R₂O/ (Al₂O₃+SiO₂) (R₂O=Na₂O or K₂O) for the non-bridge dust cake showed in the range of 1 to 25wt%, and the particle size of the potassium rich particles was in the range of 0.5 to 2.2m. However, the index for the bridge cake approached to below 5% and the particle size of the potassium rich particles shifted to the larger range of 2.2 to 10m. It was observed that weak sintering takes place by the reaction of potassium rich particles and the ash particles that adjoins the particles. Ther-modynamic equilibrium has been also examined for this system.