Drying of sugarcubes is traditionally performed with long-wave ceramic infrared heating elements. These drying units including a cooling section have a length of about 50 m, a drying/cooling time of 12 minutes with a throughput of 1600 kg/h. Required final moisture content is 0.4% (wet basis) and water evaporation required is 10 – 15 kg/h. The infrared drying unit has a low rate of heating up (max. 6°C/min) and a low thermal efficiency (38%). A feasibility study has been carried out applying microwave heating at a frequency of 2450 MHz and radio-frequency heating at a frequency of 27.15 MHz. These techniques together with infrared drying are evaluated with respect to drying performance and quality characteristics. The newly developed microwave drying process has been patented and several units are implemented on an industrial scale. In the paper the entire sequence from feasibility study to commercialisation is described. H.M. TORRINGA1, H.P.M NEIJNENS2 1. Agrotechnological Research Institute, P.O. Box 17, 6700 AA, Wageningen, The Netherlands 2. Aquarius Machinefabriek BV, P.O. Box 296, 6000 AG, Weert, The Netherlands

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Auteur : H.M. TORRINGA H.P.M NEIJNENS