Three-phase dispersions contain ßconglomeratesß (C) (drops containing solids) and solid-free drops (D). The conglomerates are larger than the drops. The effect of drop and conglomerate sizes on the coalescence rate is analyzed, and possible mechanisms for homogeneous, C-C or D-D, and heterogeneous, C-D, coalescences are discussed. Overall coalescence rate data are used to calculate the specific ... [Show full abstract] coalescence rates. Solid content, hold-up ratio of the dispersed phase, and mixing intensity affect the size of conglomerates. The latter is the most important parameter affecting coalescence. Depending on operating parameters, C-C coalescence rates are 2 to 13 times higher than D-D coalescence rates. Similarly, C-D coalescence rates are larger than D-D coalescence rates. The former is smaller than C-C coalescence rates when crystals are large and uniform and approach C-C coalescence rates in the presence of small crystals.