A new drying technology developed by researchers in Germany could dramatically reduce the amount of energy used in industry while helping companies switch from fossil fuels to renewable electricity.
Drying is an essential step in making many everyday products.
Industries use it to remove moisture from materials so they can be stored safely, processed further, or maintain their quality.
Products ranging from minerals and cement to food, detergents, paper, straw, lime, couscous, and even insect larvae all require drying during production.
Today, most industrial drying systems rely on hot air heated by burning natural gas.
While this method is effective, it consumes large amounts of energy and releases significant carbon emissions. It also wastes heat because much of the warm air escapes into the atmosphere after it has done its job.
Researchers at the Fraunhofer Institute for Interfacial Engineering and Biotechnology (Fraunhofer IGB) are working on a cleaner alternative through the LowCarbDry project.
Together with Evonik Operations GmbH and the Pergande Group, they have developed a system that replaces hot air with superheated steam while using electricity instead of fossil fuels to power the drying process.
Unlike ordinary steam, superheated steam is heated beyond its boiling point so it contains no liquid water.
In the new system, the steam circulates inside a closed loop instead of being released into the air. This allows much of the heat to remain inside the system, greatly reducing energy losses.
According to the researchers, this approach could reduce the energy needed for drying by two to four times, depending on the material being processed and the drying temperature.
Another advantage comes after the drying is complete. As moisture leaves the product, the extra steam can be condensed back into water. During condensation, heat is released at temperatures between about 90 and 100 degrees Celsius. Instead of wasting this heat, it can be reused in the drying process itself, in other industrial operations, or even supplied to local district heating systems.
The team has also integrated heat pump technology to make the system even more efficient. The heat pump captures low-temperature heat from the drying process and raises it to a higher temperature so it can be used again. Recycling heat in this way reduces the need for additional energy and lowers operating costs.
The technology can also use a process called mechanical vapor recompression. Compressors increase the pressure of the excess steam generated during drying. The compressed steam is then condensed and recycled to produce the heat needed for continued drying, further improving efficiency.
An intelligent control system makes the process even more economical. The software can automatically schedule energy-intensive drying when renewable electricity is plentiful and electricity prices are low. This allows factories to use more green electricity while reducing operating expenses.
Together, the combination of superheated steam, heat pumps, and smart controls can reduce energy consumption by as much as 80%, offering a major opportunity to cut industrial carbon emissions.
The researchers have already tested the technology on a wide range of materials, including mineral raw materials, construction products, organic waste, food, and animal feed.
In each case, they found that the process maintained product quality while delivering high energy efficiency. Pilot systems using superheated-steam spray drying are already operating, bringing the technology one step closer to widespread industrial use.
