Solids mixing and separation

Thesis/Dissertation · Thu Jan 01 00:00:00 EST 1981

OSTI ID:5313014

Liu, Y

Scaling up of fluidized-bed reactors for converting coal, oil shale, tar sands, and other resources to clean gaseous and liquid fuels is one of the unsolved two-phase flow problems. Solids mixing in fluidized beds has traditionally been treated using empirical transfer or diffusion coefficients. This study presents a new approach. A hyperbolic diffusion equation is derived by linearizing two phase flow equations of motion obtained previously by minimizing the rate of entropy production. Analytical solutions to the hyperbolic diffusion equation for a tracer concentration are obtained using Laplace transforms and the method of images. The solutions involve a propagation velocity, which is determined by two phase mass balances, and a diffusion coefficient which is a ratio of kinetic energy to interphase friction or drag, as in Einstein's diffusion coefficient. Least square curve fits of data to the theory produced reasonable values of the drag coefficients. Most synthetic fuel processes involve removing unwanted mineral solids and sulfur from the raw material. The experimental apparatus of cross-flow electrofiltration was modified to accommodate the measurements of outlet concentration by using a gamma ray density gauge. Experiments were conducted for the ..cap alpha..-Al/sub 2/O/sub 3/ particles and tetralin system. Steady state filtration rates for various operating conditions were obtained. Material balance for the filter unit can be achieved. A description of the flow field in the cross-flow electrofilter was obtained by solving a laminar annulus flow with suction through an outer porous wall. Numerical solutions were obtained by using the Crank-Nicholson finite difference method. Clear boundary layer near the filter wall can be calculated by either the finite difference method or the method of characteristics.

• OSTI ID: 5313014
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
FLUIDIZED BED REACTORS
TWO-PHASE FLOW
SOLIDS
MIXING
SEPARATION PROCESSES
COAL
DIFFUSION
ELECTRODES
ENERGY CONVERSION
ENTROPY
EQUATIONS
FILTRATION
OIL SANDS
OIL SHALES
BITUMINOUS MATERIALS
CARBONACEOUS MATERIALS
CONVERSION
ENERGY SOURCES
FLUID FLOW
FOSSIL FUELS
FUEL DISPERSION REACTORS
FUELS
HOMOGENEOUS REACTORS
MATERIALS
PHYSICAL PROPERTIES
REACTORS
THERMODYNAMIC PROPERTIES
420400* - Engineering- Heat Transfer & Fluid Flow