Areas of competencePhoto: Manuel Gutjahr
The drying group investigates and develops innovative processes for drying of agricultural products from fundamental research up to industrial implementation. The aim is to develop energy efficient and product gentle processes to be part of innovative bio-economic production systems.
Drying is one of the most important processes for a fast and safe preservation of farm-fresh agricultural products and for quality assurance along the value-added chains. However, drying is one of the most energy intensive processes in industrial engineering at the same time. Energy demand and product quality are closely interconnected: the more homogeneous and gentle the drying proceeds, the higher are energy efficiency and product quality. Over- and under-drying are minimized, and post-harvest losses are considerably reduced. Important criteria for process evaluation are, therefore, the homogeneity of drying (as possible consistent distribution of product moisture and valuable ingredients) and energy consumption.
Drying is a very complex physical process, which is characterized by heterogeneous gas-solids interactions. In the drying of agricultural products, also biochemical processes play an important role besides the physical compartment processes like particle flow, airflow and heat and mass transfer. In contrast to industrial drying goods, these products are of biogenic origin meaning that they are still biologically active after harvest. Maturity and respiration still occur in the post-harvest period. Mostly, the mechanical and thermal properties of agricultural products are non-uniformly distributed, and even single particles (e.g. grains) have a complex biological structure, which complicates the calculation of the drying process.
Comprehension of these processes is an essential precondition for a knowledge-based development and design of innovative drying processes and bio-economic production chains. For this purpose, single compartment processes are investigated and mathematically modeled. Based on these insights, process models for drying are developed and validated by experiments.
For process development in drying of agricultural products, a well-equipped drying lab with an associated analytical laboratory is available. Our research comprises the laboratory and semi-technical scale up to practice. For that matter, we closely co-operate with partners from research, agriculture and industry.