Modeling of solid/liquid expression for cellular materials

Abstract

A general theory is developed for the mechanical expression of agrofood, cellular materials. The so-called, Liquid-containing biporous particles expression model considers liquid transfer within a network of three different volumes: extraparticle, extracellular and intracellular volumes. The system of partial differential equations i s solved for the expression under constant pressure, allowing calculation of the total layer settlement, as well as the deformation of extraparticle, extracellular and intracellular volumes. The model is able to predict the behavior of four different steps in the consolidation stage: the primary deformation and the creep deformation of extraparticle volume, and the deformation and deliquoring of both extracellular and intracellular volumes. The model is applied to the hydraulic pressing of rapeseeds. The theoretical model agrees well with experimental data for the overall range of pressing time.pression of clay cakes. This is conceptually close to Terzaghi's theory, but it accounts for two periods of consolidation: the primary and the creep (or secondary) consolidations (Gibson and Lo, 1961;Florin, 1959). Shirato et al. (1974, 1978, 1986), and Rebouillat et al. (1985 have used creep consolidation models for both constant pressure and rate, and varying pressure and rate.The mechanisms for expression of mineral cakes and cellular materials are basically different. With mineral cakes, the cake is initially saturated by the liquid, and cake deformation depends only on the reorientation of individual, incompressible particles within the cake. With biological and cellular materials, the expression mechanism is much more complex. The liquid is stored mainly in cells; some gas may al:jo be present in the cellular structure. During expression the air dissipation and the cell rupture significantly modify the cake compressibility. Also, intraparticle and extraparticle volumes are compressible. Thus, the reorientation of the liquid-contaking particles and the evolution of the particle microstructure affect the local stress gradients, and consequently the expression performances. Although the mechanical expression of biological and cellular materials obeys a very complex mechanism, the authors have used the aforementioned theory and models, under constant pressure (Austmeyer, 1987;Sivala et al.

Continuous pulsed electric field treatment of French cider apple and juice expression on the pilot scale belt press

“…Juice extraction from biological materials depends on intrinsic characteristics of the tissues, such as the size of the slices, the temperature, the pre-treatment procedure and other factors (Lanoiselle, Vorobyov, Bouvier, & Pair, 1996). On the laboratory scale, the treatment of mash by PEF caused noticeable improvement in juice yield (Bazhal, Lebovka, & Vorobiev, 2001;Praporscic et al, 2007;Schilling et al, 2007;Vorobiev & Lebovka, 2009).…”

Adjustment of milling, mash electroporation and pressing for the development of a PEF assisted juice production in industrial scale

“…Material properties of the mash and processing parameters affect the kinetic of juice expression from biological tissue and attempts for the description and modeling of related phenomena have been made (Lanoisellé et al, 1996;Schwartzberg, 1997). Since the PEF treatment is affecting the mash particles in terms of the disintegration of cells and related tissue softening a change of material properties will result and could have an impact on the kinetic of juice release which may require the adjustment of processing parameters.…”

Analysis of juice colour and dry matter content during pulsed electric field enhanced expression of soft plant tissues

“…The kinetics of juice expression from soft biological tissues depends on the type of material, size of slices, temperature, pre-treatment procedure, and other factors (Lanoiselle, Vorobiev, Bouvier, & Piar, 1996;Schwartzberg, 1997). The time dependence of the relative mass losses Y is rather complex and includes different consolidation stages; so, a multi-exponential approximation is commonly used for its description …”