Pressure Drop and Liquid
Holdup in Trickle Flow Reactors:
Improved
Ergun Constants and Slip Correlations for the Slit Model
Industrial
&Engineering Chemistry Research 37 (12) pp. 4542-4550 (1998).
Ion
ILIUTA§, Faïçal. LARACHI* and Bernard Grandjean
Department
of Chemical Engineering & CERPIC,
Laval
University, Québec, Canada G1K 7P4
§On
leave from Department of Chemical Engineering
Faculty
of Industrial Chemistry
University
Politehnica of Bucharest, Polizu 1, 78126 Bucharest, Romania.
ABSTRACT
The original and extended
Holub phenomenological models for pressure drop and liquid holdup in trickle
flow regime systematically
under-predicted frictional pressure drops at elevated pressure and at high gas
throughputs. Based on an extensive historic trickle flow regime data
base and Ergun bed constants (over 4,000 measurements from 34 references
between 1959-1998), state-of-the-art correlations for shear and velocity
slip factors, and Ergun single-phase flow bed constants (Blake-Kozeny-Carman
and Burke-Plummer bed parameters) were developed. The
correlations involved combination of feed-forward neural networks and
dimensional analysis. The shear and velocity slip factors were expressed
as a function of the six most expressive dimensionless groups (ReL,
ReG, FrL, WeL, XL, StL),
whereas Blake-Kozeny-Carman and Burke-Plummer bed
parameters were correlated to particle equivalent diameter, sphericity factor,
bed porosity and column diameter. These correlations fed into the Holub's
phenomenological model improved noticeably the prediction of frictional
pressure drop and liquid holdup in trickle flow reactors.
_
You can get
the exholub.zip file to compute the liquid
velocity at the trickle-pulse flow transition.
The Fortran source codes
allow the prediction of:
- Ergun
parameters, E1 and E2
- shear slip
factor, fs
- velocity slip
factor, fv
You can get also an Excel worksheet for simulating these
parameters and more !