Modeling and Scaling Up of Industrial Spray Dryers: A Review

Abstract

The paper presents a review of research works, experiments and simulations on spray drying in the industrial scale. The research area in the industrial spray drying process covers control of powder properties (bulk density, morphology), particles agglomeration ( nal PSD), residence time, wall deposition and safety of the process and the product. Limited number of literature references on spray drying in the industrial scale is due to high costs of running experiments and validation of theoretical models. Recent works on hydrodynamics in spray towers showed transient, oscillating, 3D ow of dispersed and gas phase which results from construction of inlet and exhaust ducts and swirl decay due to wall roughness (deposits). Applications of the most advanced and accurate empirical methods to calculate spray drying kinetics in industrial scale; the Characteristic Drying Curves (CDC) and the Reaction Engineering Approach (REA) were presented. The main obstacles denying con dent scaling up of the spray drying process; lack of dynamic similarity between small and large units, gas turbulence modelling, determination of drying kinetics and neglecting of agglomeration process are highlighted. Methods of modelling of the agglomeration process in spray drying (transition functions, full scale agglomeration) are described. Examples of modelling and measurements of hydrodynamics, wall deposition, agglomeration process and drying kinetics in the industrial towers are presented and discussed.

Screening of Twelve Pea (Pisum sativum L.) Cultivars and Their Isolates Focusing on the Protein Characterization, Functionality, and Sensory Profiles

“…The protein contents were in the same range as in other studies [ 17 , 18 ]; however, other studies obtained higher protein yields (62–89%), probably attributed to the drying technique, as high losses are common during spray drying [ 38 ]. It is worth mentioning that protein isolation at industrial scale might result in higher yields when the drying kinetics are correctly determined [ 39 , 40 ]. The highest protein yield was 62.2 g protein kg −1 seed −1 obtained from the Orchestra cultivar, followed by Florida with 59.2 g kg −1 .…”

Modeling of a spray-drying process for the encapsulation of high-added value extracts from food by-products

“…For sure, there are limitations in applying this model, such as the inability to predict potential hot or cold spots that may form inside the spray dryer that can further degrade the phenolic compounds thus reducing the quality of the encapsulated product. The prediction of hot and cold spots can be made through the use of computational fluid dynamics (CFD) models (Zbicinski et al, 2017). These models give in-deep information and are very useful for the design of the equipment, but, on the contrary, are not very suitable for optimization of operating conditions due to the high computational effort required.…”

Effect of Spray Dryer Scale Size on the Properties of Dried Beetroot Juice

“…This is largely due to the fact that spray drying involves a combination of complex physical transformations that include the mixing of the main dried component and excipients in a suitable solvent, liquid atomization, solvent evaporation (drying), gas-particle separation, and often secondary drying, which may take place in a fluidized bed dryer [16]. Scale-up studies of spray dryers (particularly in the field of pharmaceutical drying) can be found in the literature and include specific process scalingup design procedures [15][16][17][18][19][20][21]. However, the limited number of literature reports on industrial scale spray drying is due to the high cost of conducting such experiments and validating theoretical models [21].…”

“…Scale-up studies of spray dryers (particularly in the field of pharmaceutical drying) can be found in the literature and include specific process scalingup design procedures [15][16][17][18][19][20][21]. However, the limited number of literature reports on industrial scale spray drying is due to the high cost of conducting such experiments and validating theoretical models [21].…”