Engineering Commons^™

Use Of A Baffle To Enhance Distribution Of A Liquid Sprayed Into A Gas-Solid Fluidized Bed, Majid Jahanmiri

Electronic Thesis and Dissertation Repository

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. …

Particle Agglomeration In A Slurry Bubble Column Due To Interparticle Liquid Bridging, Shona Macintyre

Electronic Thesis and Dissertation Repository

Particle agglomeration in heavy oil upgrading may occur due to the formation of a secondary liquid phase, known as carbonaceous mesophase. This secondary liquid phase is denser and more viscous compared to the continuous phase and may cause operational challenges. The experimental system in this work consisted of biodiesel (continuous liquid), aqueous glycerol (secondary liquid), glass beads, and nitrogen in a cold-flow, non-reacting slurry bubble column. The effects of the secondary liquid loading, secondary liquid viscosity, and particle diameter on the fluid dynamic behaviour are examined. Overall the addition of a denser and more viscous secondary liquid phase was found …

Bed Agglomeration Behavior In A Bubbling Fluidized-Bed Combustor, Ehsan Ghiasi

Electronic Thesis and Dissertation Repository

Agglomeration is a major operational problem during the combustion of biomass containing a high amount of alkali compounds. The agglomerate formation is mainly due to the presence of alkali elements in biomass ashes that form low-melting compounds in the combustion.

In the first part of this project, the critical amount of liquid that would lead to a severe agglomeration/de-fluidization was studied and determined in a lab scale bubbling fluidized bed (BFB) heated at elevated temperatures. To simulate the biomass ashes, various percentages of KCl and KCl-K₂SO₄ compounds at eutectic composition were mixed with silica sand as the …

Effect Of Temperature And Successive Sprays On Liquid Distribution In Fluidized Beds, Liliana Andrea Pardo Reyes

Electronic Thesis and Dissertation Repository

Liquid injection in gas-solid fluidized beds is used in several industrial processes including food additive production, manufacturing of fertilizers, intermediate processing of pharmaceutical capsules and oil refining (i.e., Fluid Coking^TM and Fluid Catalytic Cracking (FCC)). Good quality in the liquid distribution on the fluidized particles is fundamental in these processes either to ensure uniformity in the formation of desirable agglomerates, or to minimize their formation when undesirable. In the Fluid Coking process, for example, improving the liquid distribution and minimizing agglomerate formation will result in increasing the overall yield of the process and avoid operability problems.

A new experimental …

Effects Of Mixing And Vapor Residence Time On The Thermal Cracking Performance Of Fluidized Beds, Clayton Stanlick

Electronic Thesis and Dissertation Repository

The objective of this thesis is to investigate the effects of applied bed mixing and vapor phase residence time on the thermal cracking of agglomerating and non-agglomerating feedstock. Bitumen thermal cracking was investigated using a novel Mechanically Fluidized Reactor system and a pilot-scale Fluid Coking Reactor. Bed mixing and vapor residence time were studied to determine their impacts on agglomerate distributions, yields, and the quality of liquid product. Birchwood pyrolysis was investigated using a fluidized bed reactor to determine the impacts of particle-bed mixing on the pyrolysis of a non-agglomerating feedstock, to provide contrast to the agglomerating bitumen-coke system. It …

Factors Affecting Bed Agglomeration In Bubbling Fluidized Bed Biomass Boilers, Alejandro Montes

Electronic Thesis and Dissertation Repository

Agglomeration of bed materials at high temperature is one of the most important and challenging problems for fluidized-bed biomass boilers for thermal/power generation. Inorganic alkali components from the fuel can be problematic as they form low-melting alkali compounds. In the present study, the critical amount of liquid (molten ash in real biomass boiler operations) that would result in severe bed agglomeration and defluidization was studied in two small pilot-scales bubbling fluidized bed (BFB) rigs, one operated at room temperature using glycerol-water to simulate molten ash and the other operated at elevated temperatures using low melting-point salt (KOH) to simulate molten …

Effect Of Nozzle Geometry On Jet Bed Interaction: Experiments With Commercial Scale Nozzles And Eroded Nozzles, Nicholas A. Prociw

Electronic Thesis and Dissertation Repository

Liquid injection into fluidized bed reactors has several industrial applications, such as Fluid Catalytic Cracking, Gas Phase Polyethylene production, and Fluid Coking. High quality liquid distribution is essential to maximize the yield of desirable products, and minimize agglomeration.

The objectives of this thesis are: to develop a method that measures the rate of liquid released from agglomerates formed as a result of liquid injection into a fluidized bed; to use this method to determine the effect of internal erosion on nozzle performance; and to compare the performance of current commercial spray nozzles to nozzles with altered geometries. To achieve these …

Simultaneous Particle Agglomeration And Attrition In A High Temperature Fluidized Bed, Mithun Saha

Electronic Thesis and Dissertation Repository

Fluid Coking^TM is a major refining process to upgrade heavy crude oil or bitumen from oil sands. In Fluid Coking^TM bitumen is atomized with steam and sprayed inside a high temperature fluidized bed of coke particles where it thermally cracks into smaller molecules. Fluid Coking^TM is a carbon rejection process as solid carbon residues are formed during fragmentation into lighter hydrocarbon vapors. New coke deposits over existing coke particles and, consequently, the particle size increases. In addition, particles agglomeration occurs when the injected liquid does not disperse uniformly on individual hot coke particles but reaches, instead, local …