Air acceleration classification for the enhancement of spent catalyst activity classification

The consumption of industrial catalysts is up to nearly one million tons/year, resulting in a large amount of spent catalysts. Classifying and recycling highly active catalysts from spent catalysts reduces not only hazardous waste emissions, but also fresh catalyst consumption. In this study, a novel air acceleration classification was developed for the enhancement of spent catalyst activity classification. A theoretical equation for catalyst classification was built in accordance with the relationship between the catalyst activity and density. The optimal operating regions for the classification of different active catalysts (with catalytic activities of 0%, 25%, 50%, 75% and 100%) were obtained by theoretical calculations and experimental verification. The movement regular of different active catalysts in an air acceleration classifier was studied in detail for the enhancement of the classification. The influence of the particle shape and size on the classification was also studied, and the maximum classification efficiency reached 85.6%, thus verifying the feasibility of air acceleration classification for the enhancement of spent catalyst activity classification. This study not only benefits the activity classification of discharged catalyst in refinery industries but also serve as a useful guide for the classification enhancement of fine particles in other fields.