Two significant advances in the development of on-line tomographic imaging methods for visualization and quantification of powder flow are illustrated based on pilot-plant studies of pneumatic conveying and fluidization. The dynamic behaviour of a circulating fluidized bed is described, in which the thickness of the downflowing solids along the wall is measured. The data enables a more realistic (non axi-symmetric) model or heat transfer to the wall to be formulated. The application of electrical capacitance images to derive, in real time, visualization of moving stratified powder beds and slugs and subsequent analysis of image data for identification of the prevailing flow structure for control purposes is described.