Engineering Commons^™

Studies On Microscopic Flow Structure Inside A Rectangular Circulating Fluidized Bed Through Image Analysis, Jingsi Yang

Electronic Thesis and Dissertation Repository

The microscopic flow structure is studied systematically and comprehensively through a visualization system in a narrow rectangular circulating fluidized bed (CFB) transparent Plexiglas riser with a height of 7.6 m and a cross section of 19 mm × 114 mm. A visualization system consisting of a high-speed video camera, a light source, and image processing and analyzing programs is designed and developed to enable the flow structure to be visualized directly and studied quantitatively. FCC particles of 67 μm are used as the bed materials under different operating conditions with superficial gas velocity (U_g) and solids circulation rate …

High Density Gas-Solids Circulating Fluidized Bed Riser And Downer Reactors, Chengxiu Wang

Electronic Thesis and Dissertation Repository

A systematic and comprehensive study of hydrodynamics and reactor performance was conducted in a 76 mm i.d., 10 m high riser and a 76 mm i.d., 5.8 m high downer reactor under high density/flux operating conditions using fluid catalytic cracking (FCC) catalyst particles. An optical fiber probe was used to obtain a complete mapping of local solids holdup and particle velocity. Catalytic ozone decomposition reaction was employed to study the characteristics of reactor performance in the CFB riser and downer. The superficial gas velocity (U_g) and the solids circulation rate (G_s) were 3-9 m/s …

Particle Fluidization In Upward And Inverse Liquid-Solid Circulating Fluidized Bed, Long Sang

Electronic Thesis and Dissertation Repository

The fluidization of particles in upwards and inverse Liquid-Solid Circulating Fluidized Bed is carried out to investigate the hydrodynamic characteristics when using “heavy” and “light” particles, whose densities are higher and lower than that of the surrounding liquid respectively. Generally, the solids are fluidized upwards in the former case, whereas, the downwards fluidization is preferred in the latter scenario.

In the Liquid-Solid Circulating Fluidized Bed (LSCFB) riser, where the upwards fluidization takes place, the effects of particle properties on solids holdup are investigated experimentally based on three parameters: superficial liquid velocity, normalized superficial liquid velocity and excess superficial liquid velocity. …