(388r) Simulation of Flow Behavior of Particles in a Magnetic Liquid-Solid Fluidized Bed

Simulation
of Flow Behavior of Particles in a Magnetic Liquid-Solid Fluidized Bed

with
Uniform Magnetic Field

Shuyan Wang ^{1, 2}, Lixin Wei ², Jinsen Gao ³,Xingying Lan³

1 Department
of Chemical and Biological Engineering, Princeton
University, Princeton, NJ, United States

2
School of Petroleum Engineering, Northeast Petroleum
University, Daqing 163318, China

3 State Key Laboratory of Heavy
Oil Processing, China University of Petroleum, Beijing,
102249, China

ABSTRACT

Magnetic fluidized beds (MFB) of magnetically susceptible
particles are considered as one of the technologies developed to eliminate the
drawbacks of fluidized beds. The MFB results in an improved fluid-solid
contactor that combines the most desirable characteristics of both fluidized
and packed beds. The MFB deals
with two basic magnetization modes: Magnetization FIRST (preliminary magnetization
of fixed bed and consequent fluidization) and Magnetization LAST (magnetization
of preliminarily fluidized beds). In present study, the flow behavior of
solid phases is simulated by means of DEM-CFD in a
liquid-solid fluidized bed with LAST mode along an axial uniform magnetic
field. The magnetic force on the particle due to the nonuniform magnetic
field resulting from the interaction of the external uniform field and
nonuniform fields of the magnetized particles is predicted. By changing the
magnetic field strength, the distribution of particles is studied within the
bed. The distributions of velocity and concentration of ferromagnetic
particles are analyzed at the different magnetic field intensities. The
simulations show a significant effect on the motion of particles with axial
magnetic fields applied. When the magnetic field strength is increased to a
value at which the fluidization of strings starts, the particles are found to
form straight-chain aggregates in the direction of the magnetic field. At very high
magnetic field strengths, the defluidization is observed at which particles are
fixed in the bed. Simulations indicate the granular temperature of particles
increases, reaches a maximum, and then decreases with the increase of
magnetic-flux density. Through the analysis of the motion of particles, it is
concluded that the moderate strength magnetic field gives a high fluctuation of
particles.