GEA evaporation technologies for optimal production of nutritional powder
GEA is a world leader in providing evaporation systems for a variety of nutritional powder applications. With decades of experience, we understand that the right choice of evaporation and heat treatment technology is critical to achieve optimum product quality and retain the required functional and physical properties for nutritional powders.
Formulation methodology and evaporator design
Where the products are formulated from 100% recombined dry ingredients a smaller finisher evaporator only is required to increase the solids content from 40-42% to 50-55% ready for spray drying.
Typically a full scale evaporator is only needed for nutritional powder manufacture when it is being formulated using fresh milk as a base.
In either case a wide range of feed solids and processing rates means that nutritional evaporator plant designs and configurations require a high degree of flexibility.
During the evaporation all air incorporated during the recombination is evacuated resulting in a powder with lowest possible occluded air content.
Direct contact heating
It is well known that even short residence times at temperatures above 70°C have a major impact on product properties. And, as the use of indirect heaters often involves uncontrolled residence times, GEA’s direct contact systems supply heat instantly by condensing steam directly in the product.
The heating can take place with or without regenerative steps, depending on the energy costs and/or required heating process, and our systems can be designed to meet the exact time and temperature combination requirements of the product.
Direct contact heating is the worldwide standard within the dairy industry and offers the following benefits:
- low concentrate viscosity
- improved quality of instant whole milk powders
- low heat powders, resulting in better bacteriological properties
- tailor-made WPNI values for medium heat powders
- improved heat stability of high heat, heat-stable powders
Steam used for direct heat of nutritional products must generally be of culinary standard. This culinary steam needs to be generated using a steam reboiler.
Often multiple heat treatment systems are required for nutritional evaporators to achieve the range of feed flows and turndown required to match with a full range of nutritional formulations.
Choosing the right evaporation technology
All GEA evaporator systems provide pre-heating and heat treatment to control the microbiological product quality, and are designed to reduce energy consumption.
The low residence time in the evaporator, often as short as 10–12 minutes, provides advantages, including:
- minimum heat load on product
- short start-up and shut-down times
- low product losses
- reduced cleaning time and costs
Both MVR and TVR systems can be used as a solution for nutritional powder applications depending on the relative cost of steam and power and the required payback.
MVR Fans controlled with a variable speed drive can generally provide more flexibility and a greater range of operating conditions compared to TVR.