II International Symposium on Carbon for Catalysis ABSTRACTS

PP-<strong>II</strong>-10
Evolution of instability in a top area of FB and localization of FB in an area of the cone -
cylinder transition gives the reason to believe that FB stability depends directly on scale of
turbulence in a catalytic FB reactor. This assumption has been experimentally proved by
experiments on glass tubes with and without additional turbulators. Additional turbulence has
been provided with four vertical grooves on the internal surface of a tube. Each groove had
the shape of an equilateral triangle in cross-section with 2 mm side.
It was found experimentally that FB stability in standard tubes is realized in a range of
particles weight of 9-12 g, and in tubes with turbulators - in a range of 5 – 50 g. At the same
time the ratio of FB height to the channel diameter was 1.0-1.3 in the first case and 4.5 in the
second case (particles weight 50 g). It is important to note that tenfold change of particles
weight in the latter case is realized at constant rate of argon about 60 cm/s). This effect is
explained by compensation of viscous friction loss increasing with particles weight increase
by reduction of kinetic energy of turbulent pulsations, first of all’ due to reduction of
pulsations frequency. E.g., if the weight of particles in FB is in a level of 40 – 50, g the
amplitude of catalyst particles fluctuations in top area of FB falls up to 3 mm, and frequency
up to 0.5 Hz.
Thus, the dependence of FB stability in a catalytic reactor on a level of turbulent
pulsations was found and experimentally proved and recommendations how to increase FB
stability with increase of a bed height are given.
References
1 I.O. Protodyakonov, Yu.G. Chesnokov. Hydromechanics of a fluidized-bed. Leningrad,
Chemistry, 1982, 264 p.
2 D. Joseph. Stability of a liquid movement. М., Mir, 1981, 640 p.
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