ANALYSIS OF AGGLOMERATES MOTION THROUGH A FLUIDIZED BED AND FACTORS AFFECTING IT
Canada has the largest bitumen reserves in the world which are extracted from oil sands. Fluid CokersTM are utilized in oil refineries to crack the bitumen to produce feedstock for petroleum products. Agglomerates formation in Fluid CokersTM cause operating problems such as stripper sheds fouling. Better understanding of how agglomerates move through a fluidized bed can lead to improved design of Fluid CokerTM by minimizing the risk of agglomerates reaching regions where they cause problems.
The aim of this research is to study the motion of agglomerates and to analyse the impact of important factors that may affect it. The proposed research includes the following sections,
1. Effects of Bed Hydrodynamics on Agglomerates Motion:
A large scale fluidized bed with a rectangular cross section and an expansion zone is being used for experiments. Agglomerates are generated by operating at a bed temperature of 130 °C and injecting for a few seconds, an aqueous solution of gum arabic, a binder, to which a dye has been added. The bed is kept fluidized for a set time, and, then, defluidized. The bed is then sectioned horizontally and vertically, and agglomerates are recovered from each section by screening. The agglomerates are sieved and their concentration of gum arabic is measured to provide the size distribution and initial liquid concentration of the agglomerates recovered from each section. Initial results show that large agglomerates tend to segregate at the bottom of the bed. Further experiments are being conducted to verify the segregation of agglomerates as well as to study the effects of bed hydrodynamics on agglomerates motion in the vertical and lateral directions. Experiments shall be conducted in both bubbling and turbulent fluidization regimes to check whether agglomerates motion is affected by the fluidization regime.
2. Impact of Multiple Liquid Injections on Agglomerates Motional Behaviour
In industrial reactors, the liquid is injected through multiple injection nozzles. Hence, it is vital to know if multiple or successive sprays affect the agglomerates motion. Therefore, future experiments shall be conducted with nozzles spraying simultaneously from opposite sides (crossover from one side to the other) and with nozzles spraying successively. The sequence of injection sprays can be changed to check whether it has any impact on agglomerates. Each spray will use liquid with a different dye so that the origin of each agglomerate can be easily identified.
3. Simulation of Agglomerates Motion Using RFIDs or Radioactive Particle Tracking
RFID tags can be installed in simulated agglomerates manufactured in the laboratory to track their motion through the fluidized bed. Agglomerates can also be set up to break along predefined planes when subjected to a shear of predetermined force (breakage can be detected by inserting an RFID tag in each agglomerate half): this will provide the location and time of the breakage. Multiplane agglomerates can be developed to take in consideration the shear forces acting in different directions. Radioactive particle tracking can also be used instead of RFID tags.
4. Estimation of Liquid Lost to Burner
For this purpose, experiments shall be conducted with a circular fluidized bed through which a top to bottom solids circulation can be imposed. These experiments will help estimate how much liquid is lost to burner at different gas velocities and liquid solid ratios.
Fluid CokerTM, Agglomeration, Fluidized Bed, Thermal Cracking, Fluidized Bed Reactor, Injection Spray Nozzle
I have 4 years of versatile experience in various aspects of engineering design and execution of oil and gas processing from wellhead surface facilities to central processing facilities. Strong expertise in major aspects of basic and detail engineering design from process selection and FEED study to freeze of detail engineering design. Proficiency extends to execution, pre-commissioning, commissioning and start-up activities as well
I have also been a part of visiting faculty at University of Karachi for the final year course "Process Design and Simulation".
I currently hold 6 certifications in various areas of process engineering