Effect of interactions between spray jets on liquid distribution in a fluidized bed

Abstract

AbstractIn Fluid Cokers™, banks of spray nozzles are used to inject oil into a bed of hot coke particles. The purpose of this study is to determine whether interactions between spray jets could enhance liquid distribution on hot coke particles, which is crucial to improve the operability and performance of Fluid Cokers. A low temperature experimental model of Fluid Coking was used to measure the liquid distribution. Preliminary screening of nozzle positions employed conductance measurements. A binder solution was utilized to further investigate the most interesting nozzle interactions, by simulating at low temperature the formation of agglomerates during high temperature coking. Adding different dyes to the binder solutions injected by the different nozzles helped determine how nozzles interacted.With two synchronized nozzles of the same size, the liquid distribution is greatly improved when the spray jets slightly merge due to the expansion time being significantly reduced. The merged spray jets result in an unstable single jet, which allows for bubbles to be released faster from the spray jet. Because the volume of the released bubble is about the same for individual and merged jets, the jets do not contract as much upon bubble release: this enhances the jets' ability to capture gas bubbles from the bed, accelerating their expansion. Fewer agglomerates are also produced due to the improved liquid distribution.