CHEMICAL ENGINEERING TRANSACTIONS
VOL. 70, 2018
A publication of
The Italian Association
of Chemical Engineering
Online at www.aidic.it/cet
Guest Editors: Timothy G. Walmsley, Petar S. Varbanov, Rongxin Su, Jiří J. Klemeš
Copyright © 2018, AIDIC Servizi S.r.l.
ISBN 978-88-95608-67-9; ISSN 2283-9216
Adjustment of the Minimum Spouting Velocity in a Conical
Spouted Bed from Artificial Neural Networks
Juan F. Saldarriaga
a,
*, Fabio Freire
b
, Jose Freire
b
a
Dept.Civil and Environmental Engineering, Universida de los Andes, Carrera 1Este#19A-40, 111711 Bogotá, Colombia
b
Dept. Chemical Engineering, Universidade Federal de São Carlos, Washington Luís km 235, São Carlos, Brasil
jf.saldarriaga@uniandes.edu.co
The minimum spouting velocity is one of the fundamental parameters in the application of the conical spouted
bed pyrolysis, gasification and combustion, therefore it is necessary the adequate calculation and the use of a
correlation with good adjustment, for this an artificial neural network has been applied, in order to improve the
correlations of the literature. Six variables that involve different geometrical parameters and operation of the bed
have been used. With the purpose to compare the results of the model with the experimental data and those
predicted by the empirical equations, the quadratic error has been used. Although there is a complex relationship
between the input variables and the output variables, and despite numerous of available data, the training and
test steps of the network show a good adjustment with respect to the experimental values. This shows that an
artificial neural network is an agile method to predict the minimum velocity of the bed at the pump, especially
when the relationship between geometric parameters, operating parameters and minimum speed is complex
and difficult to define.
1. Introduction
The spouted bed reactor can achieve an intensive gas-solid contact, an important factor for the valorisation of
biomass from thermochemical processes. Likewise, it operates stably in a wide range of gas flow due to the
properties of mass and heat transfer. In this, you can process materials of different types of particle diameter
and geometry. The most recent applications of the spouted bed reactor are many and varied, standing out in
the industrial physical processes: drying of seeds, pharmaceutical powders and biomaterials (Konopka et al.,
2008), granulated (Borini et al., 2009), materials coating (Rocha et al., 1995), and solid mixture (Hao et al.,
2008). Applications in industrial chemical processes include gasification (Spiegl et al., 2010), combustion (Rasul,
2001) and pyrolysis (Olazar et al., 2001).
Different modifications of spouted bed reactor in the original have been proposed in the literature with the aim
of improving its performance. These are mainly the geometry of the contactor and the gas input to the bed, this
in order to increase the handling capacity of the coarse particles, decrease the pressure drop, improve the cyclic
movement of the particles and keep the operation stable in a wide range of gas flow velocities (Olazar et al.,
1992). In the same way, the operation can be carried out in a spouted bed reactor with very short gas residence
times (as low as milliseconds) (Olazar et al., 1992).
According to Altzibar et al. (2013a), a crucial parameter that limits the scaling of the spouted bed is the
relationship between the inlet diameter and the particle diameter, likewise, they argue that the inlet diameter
should not be 20 or 30 times larger than the average particles diameter in order to reach the condition of spouted
bed. The usual solution for this drawback is the use of a suction tube. Different configurations of the aspiration
tube have been developed: solid, porous and open (Altzibar et al., 2013b) and are especially suitable for
vigorous contact.
The minimum spouting velocity is an essential variable in the operation of a conical spouted bed and is one of
the parameters required for design and scaling. Saldarriaga et al. (2016) calculated the minimum spouting
velocity for different types of biomasses and configurations of both the contactor and internal devices, generating
new correlations for irregular particles (biomass) because those provided in the literature did not have
DOI: 10.3303/CET1870208
Please cite this article as: Saldarriaga J.F., Freire F., Freire J., 2018, Adjustment of the minimum spouting velocity in a conical spouted bed
from artificial neural networks , Chemical Engineering Transactions, 70, 1243-1248 DOI:10.3303/CET1870208
1243