Evaluation of radial voidage profiles in packed beds of low aspect ratios

N. J. MARIANI; G. D. MAZZA; O. M. MARTÍNEZ; G. F. BARRETO

THE CANADIAN JOURNAL OF CHEMICAL ENGINEERING

Canadian Society for Chemical Engineering

Lugar: Montreal; Año: 2000 vol. 78 p. 1133 - 1137

0008-4034

<!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> The relationship between the radial voidage profile ε(r), and the radial distribution of centres of monosized spherical particles f( r), is revised. A close expression is given for the section S(r, rC), the area of the segment of a cylindrical surface of radius r intersected by a particle centred at  rC . From this expression, ε(r) can be evaluated straightforward from the knowledge of f( r). The range 1£ a £ 2 of aspect ratios (a=dT/dp) is then analysed specifically. For this range, the distribution of spherical particles has been characterized theoretically (Govindarao et al, 1992) and a simple expression allows the evaluation of ε(r). The use of this expression for actual catalyst particles, imperfect spheres showing a distribution of sizes, is finally analyzed.