Master of Engineering Science
Chemical and Biochemical Engineering
Dr. Cedric Briens and Dr. Franco Berruti
During the Fluid Coking Process™ bitumen is sprayed into a fluidized bed of hot coke particles. The bitumen undergoes thermal cracking and is converted into gasses, condensable vapors, and solid coke, which deposits on the coke particles. These vapors rise through the vessel and result in entrainment of coke particles. Wet fine coke particles from the freeboard region enter the cyclone and contribute to the fouling of the Coker cyclones which can lead to the premature shut-down of Fluid Cokers.
The primary objective of this research is to determine how bed wetness affects entrainment.
First, a new fluidized bed was constructed, and a novel pseudo-isokinetic sampling was developed and tested to collect entrained solids. Then the entrainment from the dry bed in the bubbling and the turbulent regime was investigated. The cluster analysis was performed and showed an improvement in predicting the flux of solids ejected from bed surface, above the TDH, and across the freeboard.
In the next chapter, the effect of the different levels of bed wetness on flux and size distribution of the entrained particles was studied, and the results were compared to the ones obtained for the dry bed. It was observed that in the bubbling regime, the presence of liquid can change the bubble properties in the bed which will affect the entrainment. However, the effect of low liquid loading on entrainment in turbulent regime was found to be negligible.
In the final chapter, RPT was employed and it was found that the motion of ejected clusters in the freeboard could not be tracked as the clusters move too fast for the strength of radioactive that was used. Moreover, a new model to measure the entrainment of clusters in the freeboard using a modified radioactive tracer technique in which the detectors are collimated was proposed. It was found that this method only provides the decay coefficient of the clusters flux decay.
Ayatollahi, Saber, "Particle Entrainment Studies From Dry and Wet Bed" (2016). Electronic Thesis and Dissertation Repository. 3771.