Experimental study and CPFD simulation on circumferential flow heterogeneity in a disc-donut catalyst stripper

•Highly circumferential flow heterogeneity identified in FCC disc-donut strippers.•CPFD model successfully predicted the observed circumferential flow heterogeneity.•Distributions of unfluidized zones in disc-donut strippers predicted successfully.•Full spectrum of particle size distribution – a possible key to CPFD model’s success.