Doctor of Philosophy
Chemical and Biochemical Engineering
Dr. Franco Berruti and Dr. Cedric Briens
In Fluid CokingTM or Fluid Catalytic Cracking liquid feedstocks are injected into a bed of fluidized particles. Uniform distribution of liquid feed on fluidized particles increases the yield of valuable products and improves operability in these processes. Contact between the injected liquid and the bed particles can be greatly affected by the liquid properties and local bed hydrodynamics.
The impact of parameters such as liquid properties, fluidization velocity, nozzle atomization gas flowrate, nozzle location and inclination were investigated on the distribution of liquid sprayed into a fluidized bed with a reliable and fast response capacitance meter. This method was also extended to monitor the agglomerate breakup kinetics.
The research showed that a liquid whose viscosity and contact angle on the surface of solid particles are similar to the liquid used in the high temperature commercial reactors provides a good simulation of liquid distribution into a fluidized bed with room temperature experiments. VarsolTM was selected for a cold simulation of Fluid Cokers.
The research also presents an innovative design of a cold model fluidized bed to investigate the impact of the velocity of particles, relative to the spray nozzle, on solid-liquid contact since it varies greatly with location in actual Fluid Cokers. This design provided an inexpensive and accessible means to study the effect of the relative velocity between the spray jet and particles independently of other bed hydrodynamic characteristics.
The investigation found that distribution of the injected liquid in the bed can be improved by either increasing the atomization gas flowrate or, preferably, the fluidization velocity. Study of nozzles at different locations and inclinations identified the dominant effects of bed hydrodynamics at the nozzle and jet tips on the distribution of liquid on solid particles.
A model for the interactions between sprayed liquid and fluidized particles was developed for two cases: a) a stationary spray nozzle and no net motion of the fluidized solids and b) a moving nozzle with a relative velocity between spray nozzle and particles. The model results were compared with experimental results and were found to provide consistent information on the liquid concentration of the agglomerates.
Mohagheghi Dar Ranji, Maryam, "Impact of Local Bed Hydrodynamics on Jet-Bed Interaction" (2014). Electronic Thesis and Dissertation Repository. 2656.