Studies on the mechanism of binderless granulation of TiO ₂ in a spouted fluidized bed

The TiO ₂ fluid catalyst particles to be used in a spouted fluidized bed for de-NO _x were prepared by binderless granulation in a tapered fluidized bed. The effects of the gas velocity and the operating time on the growing of the granules, size distribution, and the yield were studied through a series of experiments and modeling simulations. Both granulating action and breaking action occurred during the binderless granulation process, since a bimodal distribution of the granule size was developed with the operating time, especially under higher gas velocities. These two actions strongly controlled the growing and the shaping of granules. A numerical model for simulating the granule growing was simulated. The simulation result was quite agreeable with the experimental data. The photocatalytic de-NO _x effect of the granulation product was tested in a spouted fluidized bed with 110 mm ID and 1200 mm height. This is an abstract of a paper presented at the 7th World Congress of Chemical Engineering (Glasgow, Scotland 7/10-14/2005).