Modeling and simulation of milk emulsion drying in spray dryers

Abstract

-This work aims at modeling and simulating the drying of whole milk emulsion in spray dryers. Drops and particles make up the discrete phase and are distributed into temporal compartments following their residence time in the dryer. Air is the continuous and well-mixed phase. Mass and energy balances are developed for each phase, taking into account their interactions. Constitutive equations for describing the drop swelling and drying mechanisms as well as the heat and mass transfer between particles and hot air are proposed and analyzed. A set of algebraic-differential equations is obtained and solved by specific numerical codes. Results from experiments carried out in a pilot spray dryer are used to validate the model developed and the numerical algorithm. Comparing the simulated and experimental data, it is shown that the model predicts well the individual drop-particle history inside the dryer as well as the overall outlet air-particle temperature and humidity.

Size distribution of agglomerates of milk powder in wet granulation process in a vibro-fluidized bed

“…Although, the list of the papers dealing with the influence of certain technological parameters on the properties and/or quality of the granules formed by layering in a fluidized bed is quite long, the number of those dealing with granules formed by agglomeration in the same bed is smaller and the number of analyses on agglomeration process of particles in a vibrofluidized bed is even smaller (Cruz et al, 2005;Birchal and Passos, 2005;Erdesz and Ormos, 1986;Erdesz, 1984). The aim of this paper is to make one more step in the explanation of the influence of the energetic action of vibrations, temperature of vibrofluidized bed, and granulation liquid feed on the kinetics of growth as well as size distribution of milk granules obtained in a wet granulation process in a vibro-fluidized bed.…”

Final Drying of Whole Milk Powder in Vibrated-Fluidized Beds

“…In the second drying period, the solid crust thickens increasing its resistance to the vapor diffusion. [3] As a consequence, the drying rate decreases and spray dryer becomes less efficient in proceeding water removal. Below 7% of moisture content, milk powder should be dried in another type of dryer that can well adjust heat transfer and water evaporation rates to minimize energy consumption, to avoid excessive increase in the particle temperature, and to improve the instant powder quality.…”

“…Simulation of the temperature and moisture content of a single milk particle as a function of its residence time in the spray dryer and the drying mechanism. [3] Final Drying of Whole Milk Powder 2023 the spray dryer. Moreover, exit air carries out fine particles, which are not agglomerated, to cyclones (see Figure 1) or sintered bag filters, [4] where they are separated from air and recycled to the spray chamber.…”

Modeling a production scale milk drying process: parameter estimation, uncertainty and sensitivity analysis

“…The drying plant normally presents three sequential stages: 1) spray chamber, in which drying occurs within a few seconds; 2) internal stationary fluid bed, added at the conical base of the spray chamber to better control particle agglomeration and drying (Birchal and Passos, 2005); and 3) external fluid bed to fine tune the powder moisture and to cool the outfeed product stream. Fig.…”