Eduardo Alberto Borges da Silva – eduardo@labsin.ufsc.br
Selene M. A. Guelli Ulson de Souza – selene@labsin.ufsc.br
Universidade Federal de Santa Catarina, Departamento de Engenharia Química e Engenharia
de Alimentos, LABSIN - Laboratório de Simulação Numérica de Sistemas Químicos
88.040-900, Florianópolis, SC, Brasil

The transient mathematical model of a simulated moving bed unit is presented. The model considers the switching of the inlet and outlet points of the fluid streams of the unit at each switching time. It is considered the plug flow with axial dispersion to fluid phase. It is used the linear driving force approximation to related the mass transfer between the fluid and solid phases. It is simulated the chromatography separation of bi-naphtol enantiomers and analyzed the transient behavior of a simulated moving bed unit with different subsections numbers in this separation. In order to resolve the differential equations of the model it is utilized the finite volume method with the WUDS scheme. It is analyzed the influence of the overall mass transfer coefficient on performance of the simulated moving bed in the separation process.

Keywords: Simulated moving bed, Modeling, Transient
 
 

ISABEL C. TESSARO
KEIKO WADA
EDUARDO G.F. FERREIRA
Department of Chemical Engineering, Federal University of Rio Grande do Sul 90040-040, Porto Alegre-RS-Brazil

Acid whey is a liquid byproduct of cottage cheese manufacturing and it is considered an important source of proteins that could be used for human consumption. The effective utilization of the large volumes of whey produced represents a significant challenge to the dairy industry. The most promising process to recover whey proteins is ultrafiltration. The main advantage of using ultrafiltration as a method to increase the aggregate value of cheese whey is that this process allows a variation in the concentration relationship among its several components. This work presents a study of the concentration characteristics of acid whey by means of ultrafiltration. The influence of several parameters, such as molecular weight cut off, spacer geometry, feed composition on the retention and permeate flux behavior have been investigated. In order to chose a membrane configuration with a proper retention and good operating conditions the following parameters have been analyzed during the UF experiments: hydraulic permeability, permeate flux, the total concentration of solids and protein concentrations. The experiments were performed in a UF pilot equipment, using three commercially spiral wound modules with two different molecular weight cut-of and two different spacer geometry. The present study gives a good insight on the interactions within membrane filtration in the concentration of acid whey, and a  real evaluation of the possibility of using UF to concentrate acid whey in the local dairy industries.