Surface fractality of wood charcoals through small-angle X-ray scattering
- Kansas State Univ., Manhattan, KS (United States). Dept. of Chemical Engineering
Geometrical properties of the pore-solid interfaces of devolatilized charcoals from the pyrolysis of fuel woods in a bench-scale fluidized-bed reactor were investigated through small-angle X-ray scattering. Specifically, surface morphological features of the interfaces were characterized by a single parameter indicative of the degree of surface roughness, that is, the surface fractal dimension, d{sub SF}, at various retention times. The surface fractal dimensions of the original wood samples prior to devolatilization were approximately identical for all species within the range between 2.00 and 2.15, over a length scale from 55 to 600 {angstrom}, and those for the respective charcoals from these wood samples were influenced to different degrees by the retention time, {tau}, in the reactor. The d{sub SF}`s of the mesopores of charcoals of all the species attained maxima at a value of {tau} equal to 35 s and decreased subsequently with an increase in {tau}. The analysis of this unexpected trend was facilitated by the values of the mean radii of gyration of the pores, estimated through the Guinier plots. The results imply that when the retention time of the charcoals in the reactor is prolonged, the mechanism of pore enlargement and smoothening of the interfaces can play a dominant role in altering the surface morphology and thereby influence significantly the kinetics of chemical reactions in heterogeneous porous systems.
- OSTI ID:
- 367805
- Journal Information:
- AIChE Journal, Journal Name: AIChE Journal Journal Issue: 7 Vol. 42; ISSN 0001-1541; ISSN AICEAC
- Country of Publication:
- United States
- Language:
- English
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