Effect of successive sprays on liquid distribution in fluidized beds

Abstract

In processes such as Fluid Coking™, agglomerate formation should be minimized since it reduces the yield of valuable products, and degrades operability because of the fouling of internals. An experimental model, consisting of an aqueous solution of gum arabic with a dye, has been successfully developed to simulate the formation of agglomerates in the Fluid Coking™ process, where bitumen is sprayed into a fluidized bed of coke particles The particles wetted by a spray could be predicted by assuming that all the particles in the wake of bubbles formed from the tip of the spray jet have been wetted by the injected liquid. The transfer of liquid from particles wetted with the spray to dry bed particles was relatively ineffective, as the number of wet particles increased by only 50%. With successive liquid injections, the proportion of the liquid trapped in agglomerates increases in latter injections: large agglomerates from earlier injections accumulate above the grid and are carried by gas bubbles into the spray jet cavity, where they seed fresh agglomerates.