Photo: Thomas Steen Sørensen

Major energy savings for food industry: drying with air dehumidifiers

Wednesday 29 Jun 16
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by Lisbeth Lassen

Contact

Brian Elmegaard
Head of Section, Professor
DTU Mechanical Engineering
+45 45 25 41 69
Drying is used in many industrial processes, for example in food production, and drying processes account for a substantial part of energy consumption in the industry. Now, the SteamReg project has developed and tested a new technology for energy recovery from drying air—a solution which can reduce energy costs by 50 per cent.

The project is a partnership between DTU Mechanical Engineering, the Danish Technological Institute, Cotes, and DryingMate, and the project has recently been award the 2016 ELFORSK Prize. The award was presented by HRH Crown Prince Frederik at the Energy Summit of the Danish Energy Association on Thursday, 9 June.

SteamReg—a completely new technology for energy recovery from drying processes
“The technology offers the possibility of energy savings in industrial drying processes requiring dry and hot air. The heat is recovered by generating superheated steam,” says Postdoc Lorenzo Bellemo from DTU Mechanical Engineering. “The system saves a lot of energy in relation to the existing systems, because it is able to exploit the superheated vapour.”

It is a further development of a so-called sorption dehumidifier which has a rotor that absorbs moisture by means of a rotor material of silica gel. In the dehumidification phase of the process, energy is supplied to ensure that the rotor is constantly ready to absorb new moisture. The energy is normally lost because it is led to the surroundings as a waste. But in SteamReg’s new system, this energy is reused in the actual system. It can be done by means of an MVR (Mechanical Vapour Recompression) heat pump which is able to re-use vapour condensation energy in the process.

The project partners expect to produce 20 systems for drying of milk powder over the next four years.

Photo: Casper Helmer
From left to right: Thomas Rønnow, CEO Cotes, Lars Ove Reinholdt, Head of Section at the Danish Technological Institute, Ebbe Nørgaard, Director of DryingMate (in the middle), Rasmus Toftegaard, CTO Cotes, and Postdoc Lorenzo Bellemo from DTU Mechanical Engineering (far right). Photo: Casper Helmer.