A new drying process engineered by researchers in Germany has the potential to significantly cut industrial energy consumption while aiding companies in transitioning from fossil fuels to renewable energy sources.
Drying plays a crucial role in manufacturing many everyday items. Industries rely on it to eliminate moisture from materials, ensuring safe storage, further processing, or maintaining product quality. From minerals and cement to food, detergents, paper, straw, lime, couscous, and even insect larvae, many products require drying during production.
Currently, most industrial drying systems use hot air heated by burning natural gas. Although effective, this method consumes large amounts of energy and produces considerable carbon emissions. It also results in heat wastage, as much of the warm air escapes into the atmosphere after serving its purpose.
Researchers at the Fraunhofer Institute for Interfacial Engineering and Biotechnology (Fraunhofer IGB) are exploring a cleaner solution through the LowCarbDry project. In collaboration with Evonik Operations GmbH and the Pergande Group, they’ve developed a system that replaces hot air with superheated steam, powered by electricity rather than fossil fuels.
Superheated steam is steam heated beyond its boiling point, so it contains no liquid water. In this innovative system, the steam circulates within a closed loop rather than being vented into the air, which helps preserve heat inside the system and drastically reduces energy loss. The team claims this method could cut energy requirements for drying by two to four times, depending on the material and drying temperature.
An additional benefit appears after the drying process. As moisture escapes from the product, the residual steam can be condensed back into water. During condensation, heat is released at temperatures roughly between 90 and 100 degrees Celsius. Instead of letting this heat go to waste, it can be reused for ongoing drying, other industrial processes, or directed into local district heating networks.
The system also incorporates heat pump technology, which captures low-temperature heat generated during drying and elevates it to higher temperatures for reuse, thus reducing energy demands further and lowering operating costs. Mechanical vapor recompression is another technique used; compressors increase the pressure of excess steam, then condense and recycle it to generate the heat needed for continued drying, boosting efficiency.
An intelligent control system optimizes the process by scheduling energy-intensive drying phases during periods when renewable electricity generation is high and prices are low. This strategy helps factories maximize green electricity use while minimizing operational expenses.
Combined, superheated steam, heat pumps, and smart controls could cut energy consumption by up to 80%, presenting a significant opportunity to reduce carbon emissions in industry.
The researchers have tested this technology across various materials, including mineral raw materials, construction products, organic waste, food, and animal feed. In every case, they observed that product quality was maintained while achieving high energy efficiency. Pilot systems utilizing superheated-steam spray drying are already in operation, bringing this promising technology closer to widespread industrial adoption.