PEREIRA, M. M. F.; http://lattes.cnpq.br/1468627574331513; PEREIRA, Magnus Melo Formiga.
Abstract:
The present work deals with the adsorption of methanol in fixed bed
of zeolite pellets. The dynamics of the column was studied by means of the
breakthrough curves obtained by a response to a step perturbation at the
input. The breakthrough curves were obtained by refractometric analysis of
the concentration of the mcthanol'toluene solutions at the output of a 3 cm
diameter, 16 cm high column. The concentration of the input solution was
varied between 10% and 20% by weight of methanol in toluene with a flow
rate from 0,32 ml/s to 4,4 ml/s. All the experiments were done with input
temperature in turn of 30°C . The breakthrough curves are influenced by
the flow rate as well as by the input concentration. It was observed that the
effect of flow rate is more important at low input concentrations. In these
situations it may be observed that the axial dispersion tends to be negligible
as the flow rate increases. It was also observed that the rate of adsorption
increases with the input concentration. Nevertheless, this effect is only
important for the breakthrough curves obtained at low flow rates. The
Thomas model, for Langmuir equilibrium, and The Adams & Burhart
model, as a limit to rectangular isotherms were used to model the dynamics
of the column. Both models were chosen based in previous results obtained
about equilibrium isotherms of the system. The global transfer coefficients
were estimated by fitting the experimental breakthrough curves. In spite of
the drastic simplifying hypothesis, both models fit well the experimental
data. Nevertheless, the Thomas model predicts the breakthrough curves
with good agreement in all the situations studied in this work but the
Adams & Borhart model is worst, specially at low flow rate. The transfer
parameters obtained in this work are useful for the knowledge of the
dynamics of adsorption of methanol in fixed bed of zeolite 4A pellets.
