Electronic Thesis and Dissertation Repository


Master of Engineering Science


Chemical and Biochemical Engineering


Dr. Cedric Briens

2nd Supervisor

Dr. Franco Berruti

Joint Supervisor


Bubbles in gas-solid fluidized beds are generally beneficial as they promote solids mixing, heat transfer and mass transfer. In most fluidized beds, the local bubble gas flux varies greatly over the cross-section. A novel triboelectric method is developed to measure the bubble gas distribution in a fluidized bed. A correlation relates the local bubble gas flux to the triboelectric signal generated by the impact of the gas bubbles on a triboprobe. Several signal analysis tools, such as power spectrum, cycle analysis and signal moments, were used to determine the best experimental fit for the profile of the bubble gas flux. The triboelectric method is used to study the impact of baffle and fluxtube on the distribution of the gas bubbles.

Efficient and uniform liquid feed distribution in Fluid CokersTM enhances the yield of valuable products and the coker operability by reducing the formation of wet agglomerates. A promising method to improve liquid distribution could be the modification of bed hydrodynamics and mixing characteristics using ring baffles with and without fluxtubes. In small scaled-down bed, such a baffle changed the fluidized bed hydrodynamics by redirecting gas bubbles above the baffle region, directed towards the jet spray, which improved liquid distribution by reducing agglomerate formation. The experimental results show that the best liquid distribution is obtained when the tip of the liquid injection nozzle is aligned just above the baffle tip. As long as the baffle angle with the vertical is less than 45o, this will also prevent the formation of any deposit on the baffle.

Stable jet spray.mp4 (1678 kB)
Stable Jet Spray