Project Details
Projekt
Investigation on the usage of effervescent atomization for spraying and spray drying of complex rheological food liquids and on the resulting particle and product properties
Applicant
Professorin Dr.-Ing. Heike Karbstein
Subject Area
Mechanical Process Engineering
Term
from 2009 to 2015
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 122387630
Spray drying is the key process step in the production of powdery food. For cost reduction and improved yield, it is favorable to use less water and a higher solid content in the feed. This may be single-phase or multiphase feeds, which often show a complex rheological behavior. If the viscosity of the feed increases due to a higher solid content, atomization is more difficult to achieve with conventional pressure atomizers. At higher viscosities, the use of pneumatic atomizers would be beneficial, however they are often declined due to a high gas consumption. Therefore, this research project focuses on the use of a special internal mixing pneumatic atomizer called effervescent atomizer for spraying and spray drying, which has a particularly low gas consumption. The main goal of this proposal is to investigate the scientific fundamentals of the effervescent atomization. This will enable its usage for complex compounded foods and control of the resulting powder characteristics after the spray drying process. Essential process and property functions will be established in order to allow specific product development and control of the particle characteristics (recursive process design). This requires the definition and exemplary description of the atomization and the drying of the drops. The particle structure and its influence on product properties is also needed to establish the desired process and property functions. Starting from previous results, one focus will be on the process parameters required for narrow drop size distributions and stable sprays. Investigations on the influence of the flow pattern inside the atomizer in addition to ALR (process parameter) on the spray performance will have priority. Therefore, this will be the subject of different experimental work and 2D/3D-simulations (to be conducted by cooperation partners). Concerning this, a mathematical model invented and used by subproject B10 (Weigand) will be applied. It will help to identify relevant geometrical parameters of the atomizer for aligning its design to achieve the desired spraying results.Second focus will be the categorization and rating of the effervescent atomization compared to conventional atomization process. For this purpose, the spray performance, the efficiency of atomization as well as its influence on the inner structure of multiphase feeds (emulsion) will be examined. Furthermore, selected product properties which are of interest for producer and consumer will be studied.
DFG Programme
Priority Programmes
