Dermeval Sartori

STUDY OF THE DRYING KINETICS IN THIN LAYER: FIXED AND MOVING BED

Abstract Drying kinetics of soybean seeds were investigated in the fixed bed (which is normally used) and in the moving bed with cross flow, both being run under thin-layer conditions. The analysis of the available data followed the diffusive model approach with re-parameterization. Special attention has been given to the nonlinearity inherent in the database in order to evaluate the statistical properties of the least squares estimator. The results showed that the effective diffusivity of the moving bed is 24 to 44% higher than that of the fixed bed.

Quality of Soybean Seeds Undergoing Moving Bed Drying: Countercurrent and Crosscurrent Flows

The present work describes and analyzes Brazilian research related to the quality of soybean seeds dried in moving bed dryers. The main process variables were drying air temperature, relative humidity and velocity, and solid flow rate. The statistical methodology used allowed the achievement of empirical equations for predicting the quality of soybean seeds (germination, vigor, and fissures) in two classical configurations of the moving bed: countercurrent and crosscurrent. The results show that the increase of the seed coat cracking is associated to conditions that lead to a high drying rate. Germination and vigor reduction is also associated to the overdrying conditions.

Analysis of shrinkage phenomenon in Brachiaria brizantha seeds.

ABSTRACT Picnometry and image analysis were used to measure and analyze the dimensional shrinkage of Brachiaria brizantha seeds due to reduction in the moisture content. The data were statistically treated and an equation to relate the shrinkage phenomenon with the moisture content was obtained.

Drying of seeds and gels

ABSTRACT In an attempt to contribute to the integration of research that deals with the drying of seeds and gels, the aim of the present study is to analyze the drying of porous particles covered with a gel layer, whether natural or artificial. Two case studies are presented. In the first case, the emphasis is to study the combined effect of heat and mass transfer and the shrinkage in the drying of mucilaginous seeds. The focus of the second case study is the development of an experimental methodology for coating seeds with a gel-based polymer.

Fluid Flow Effect and Mechanical Interactions during Drying of a Deformable Food Model

The purpose of this work was to evaluate a mathematical representation for the drying of a spherical food model, including the fluid flow effect and mechanical interactions. Drying kinetics data were obtained under a laminar fluid flow and the mechanical properties were evaluated through compression tests. The drying model considers two-dimensional mass transfer and the mechanical model was formulated from elasticity theory. The solution made possible the understanding of the fluid flow effect on mass transfer and the relationship between drying stresses and physical degradation of the food models.

Drying stresses and strains in a spherical food model

An approach to model the drying mechanical effects occurring in a single sphere, representing a food model, is proposed. The mechanical properties were evaluated through compression tests and drying kinetics data were obtained under a laminar fluid flow. The Fickian model was used to represent the moisture content profiles and the mechanical model was formulated from elasticity theory. Deformations and cracks predicted from numerical solution were in agreement with experimental observations. This work helped to understand the relationship between mass transfer, shrinkage, stresses, strains and physical degradation.

PRODUÇÃO DE MALTE DE NOZES DE MACADÂMIA E MODELAGEM MATEMÁTICA DA SUA SECAGEM POR CONVECÇÃO NATURAL

1* Bolsista PIBIC, Universidade Federal do Espirito Santo, Departamento de Engenharias e Tecnologia Bolsista PIVIC, Universidade Federal do Espirito Santo, Departamento de Engenharias e Tecnologia 3 Professor, Universidade Federal de Sao Carlos, Departamento de Engenharia Quimica 4 Professor, Universidade Federal do Espirito Santo, Departamento de Engenharias e Tecnologia *email: layravalani@gmail.com