Abstract: The drying principle of the droplet in the spray forming process of FCC catalyst was studied, and the reason for the formation of irregular particles and fine powder with diameter less than 40 μm were analyzed. A new structure spray nozzle was designed to control the formation of irregular particles and reduce the formation of fine powder. The new structure spray nozzle could introduce cold air around the material-liquid conical atomization layer (fog cone) in the spray drying column, and cut off the direct contact between the slurry atomization droplets and the high-temperature atmosphere entering the column. A relatively mild drying environment was established for atomizing droplets. Compared with the conventional operation, the number of irregular particles was obviously reduced and the sphericity of the catalyst particles was obviously improved with the highest value of 0.941 ( raised by 0.013). At the same time the yield of the catalyst under the spray drying column was increased by 5.2 percentage points, and the production of fine powder was reduced by about 1 percentage point.

Key words: fluid catalytic cracking, catalyst, sphericity, fine powder, drying condition