Liquid flow distribution and particle–fluid heat transfer in trickle-bed reactors: the influence of periodic operation

Reaktoren für Dreiphasen-Reaktionen: Rieselbettreaktoren

“…l ) angegeben und in Analogie zu k ls (siehe Abschn. "Stofftransport") für die einphasige Durchströmung von Schüttungen entsprechend (Boelhouwer et al 2001a;Huang et al 2004) und Thermistoren (NTC-Widerstand) (Marcandelli et al 1999;Borremans et al 2004).…”

“…Zum Teil wurden signifikante Umsatzsteigerungen bis zum Pilotmaßstab erzielt (Tukač et al 2007;Schubert et al 2006;Lange et al 1994;Castellari und Haure 1995;Khadilkar et al 1999;Stradiotto et al 1999;Liu et al 2005). Ob die periodische Betriebsführung die Phasenverteilung verbessert und Fehlverteilungen reduziert, ist dagegen bisher nicht eindeutig beantwortet (Borremans et al 2004;Liu et al 2009;Schubert et al 2010b). Durch die Modulation bei höheren Frequenzen kann das Pulsregime hin zu kleineren Durchsätzen vergrößert werden.…”

Structure of trickle-to-pulse flow regime transition and pulse dynamics at elevated temperature in slow-mode cyclic operation

“…The rate of decay and duration of tail were found to decrease with increasing superficial liquid base velocity, and to increase with distance from bed top. Borremans et al (2004) investigated the effect of periodic operation on the liquid flow distribution by using a multi-compartment liquid collector located beneath a 0.3 m diameter column packed with 3 mm glass beads up to a height of 1.3 m. They observed only marginal effects of periodic operation on bed cross-wise liquid flow distribution. Giakoumakis et al (2005) quantified the extent of pulse attenuation in fast-mode cyclic operation and reported the effects of liquid and gas flow rates and liquid feed frequency on the pressure drop, the liquid holdup and the pulse intensity and velocity.…”

Modulation of liquid holdup along a trickle bed reactor with periodic operation

“…So far, only a few contributions accounting for the influence of liquid flow modulation on the hydrodynamics of a TBR have been reported. Furthermore, the effect of non-steady state operation on liquid hold up, mass transfer coefficients and wetting efficiency has been scarcely investigated (Boelhouwer, 2001;Borremans et al, 2004;Giakoumakis et al, 2005). Only very recently, Trivizadakis et al (2006) studied the imposed pulse characteristics employing porous spherical and cylindrical extrudates.…”