Liquid holdup was measured as function of gas and liquid mass flow in the t
hree-levels-of-porosity (TLP) reactor. Packing material and bed height were
varied. Because a TLP reactor contains layers of catalyst there is an addi
tional bed holdup compared to conventional trickle-bed reactors. Liquid bed
holdup is composed of two parts: below the capillary fill height the inter
particle pores are completely filled with liquid, above this height the liq
uid holdup is well described by literature relations for single-phase trick
le-now. Using residence time measurements it was shown that no stagnant zon
es for liquid flow existed in the tested TLP packings. (C) 1999 Elsevier Sc
ience Ltd. All rights reserved.