Thermal Process Engineering Laboratory

Process engineering is concerned with the technical implementation of processes that specifically change substances according to their type, properties and composition. Thermal process engineering is about processes that involve heat, especially heat transfer. How can heat be applied to a product and thus, for example, components can be separated from a mixture? Thematically, the focus is on thermal separation processes such as drying, distillation / rectification, absorption, adsorption, extraction and crystallization.

The students complete their practical courses in the high-quality equipped facilities of the Thermal Process Engineering - a laboratory and a pilot plant. Thus, a wide range of drying apparatus is available for the training, with which (almost) any foodstuff can be dried. Spray dryers, which are very widely used in the food industry and are mainly used in the dairy industry for the production of milk powder, are available here on a smaller scale for teaching purposes. Two fluid bed granulation systems enable, among other things, the granulation and coating of originally powdery products. To evaluate the raw materials used and the products produced, the pilot plant has modern analytical equipment, such as a digital microscope or a laser diffractometer for determining particle size distributions in powders or granules. The laboratory equipment can also be used for project work and research activities.

The topics of the practical courses from the compulsory as well as the elective area, with which the students apply and deepen their acquired knowledge from the lectures, are "Thermal Process Engineering", "Drying Technology", "Heating and Refrigeration Technology" and "Food Process Engineering". One focus is on drying technology. In this subject area, students determine the characteristic drying behavior (drying curve) of various products. In addition, they learn how to produce milk powder, in particular how to influence the production process so that certain properties such as solubility or particle size - the powder must not dust, for example - are guaranteed. The students also gain an insight into the freeze-drying process. This form of drying is used for temperature-sensitive products or products whose outer shape is to be retained during drying, for example pieces of fruit. In addition, aroma- and alcohol-containing red wine granules are produced in regular student project work.

A large area is taken up by research activities. This includes research work in the context of doctoral theses as well as final theses (Bachelor and Master). Special apparatus such as a levitator can be used for this purpose. With it, single droplets can be kept in levitation to observe their drying behavior under different conditions. Another research topic is the encapsulation of microorganisms, which should make it possible to stabilize probiotic bacteria in such a way that they can reach their site of action, the human intestine, in sufficient numbers alive.

The equipment of the laboratory and the pilot plant is of high quality and extensive:

• Digital microscope to evaluate e.g. granules (structure, surface, particle size).
• Fluid bed granulation apparatus: This device can be used to produce granulates or encapsulate probiotic bacteria, for example.
• Test station for heat exchangers: This experimental setup can be used to experimentally teach the fundamentals of heat transfer in different heat exchanger designs (e.g. plate, shell-and-tube or tubular heat exchangers).
• Spray dryer to produce e.g. milk powder
• Freeze-dryer: This device can be used to dry products that need to be dried gently because they cannot tolerate temperature.
• Levitator for preliminary tests for spray drying by examining single drops
• Hardness tester (analyzer) for testing the hardness of small particles - measures the point - force and path - at which a particle breaks
• Laser diffractometer / Mastersizer 2000 (analyzer): This equipment can be used to measure particle size distributions in powders or granules, such as from a spray-dried product.
• device for differential scanning calorimetry (DSC): This device can be used to determine material properties of substances, e.g. the melting or crystallization behavior of foodstuffs or the raw materials used.
• Magnetic levitation balance for measuring sorption equilibrium - how much moisture does a product absorb depending on the ambient humidity?
• Density meter: This device can be used to measure the density or specific gravity of liquid substances.
• Rotary evaporator: This device can be used to remove water from a liquid in a vacuum. For example, milk can be concentrated before it is fed into the spray dryer.