Boreskov Institute of Catalysis of the Siberian Branch of Russian ...

PP-III-13through one layer of ACC with different pore sizes were used to calculate opening diameters(d o ) and correlations for dimensionless friction factors (f). Liquid-solid mass transfercoefficients k m for Pd-Cu/ACC catalysts with different pore sizes were determined undermass-transfer-limited operation according to a simple one-dimensional model of the testreactor.For beds of spheres and monoliths with square cells classical literature expressions havebeen adopted and relevant variables were expressed in dimensionless form by calculating theSherwood (Sh), Schmidt (Sc), and Reynolds (Re) numbers, using pore diameter as thecharacteristic length, specific for each support (d p for pellets, d h for monolith). (Table 1).characteristicdimensionrelationship betweenS v and bed porosity emass-transferSh=aRe b Sc 1/3coefficientfriction factor 2f=(1- ε)/ ε 3 [1.75+150((1-ε)/Re)]Table 1.pellet monolith woven clothd p d h d od p S v =6(1- e) d h S v =4 e d o S v = e (1- e)Sh=2.977[1+0.095(Re/ Sh=0.24Re 0.56 Sc 1/3ε)Sc(d/L)] 0.45f=14.23/ ε Ref=2.66+0.75/Re100ceramic monolith (e=0.7, d/L=0.000001)ACC (e=0.85)104* (d SV Sh)/(2f Re Sc)10spheres (e=0.4)11 10 100 1000ReFigure 2. Conversion–pressure drop tradeoff index for different catalysts.The obtained results of tradeoff index calculations (Figure 2) demonstrate that reactorwith woven cloths perform much better than those with packed beds of spheres, whose indexis strongly penalized by the high pressure drop across the bed. On the other hand, theadvantage of cloth over monolith increases at lower liquid velocities (lower Re).References1. U. Matatov-Meytal, M. Sheintuch, Appl. Cat. A. 231(2002) 1.2. U. Matatov-Meytal, Ind. Eng. Chem. Res., 44 (2005) 9575.328