Performance Evaluation of a Commercially Available Desiccant-Based Seed Drying System

HighlightsDesiccant-based convective drying systems can remove moisture from agricultural commodities.More than 85% of FlexiDry system’s energy consumption was used for desiccant regeneration.Desiccant regeneration provides an opportunity to switch from natural gas or propane combustion to electricity.Greenhouse gas emissions can be reduced in desiccant drying systems by the increased use of renewable electricity.Abstract. FlexiDry® is a commercially available desiccant-based drying system designed to reduce seed moisture content and promote seed preservation. The purpose of this study was to evaluate FlexiDry in drying 130 kg of whole yellow corn kernels (Zea mays) for large-scale human and animal consumption. FlexiDry was tested in two treatments, using heated (HA) and unheated (UA) air, and compared to conventional heated-air (CHA) drying. The desiccant (Drying Beads) was regenerated (moisture removed) at 250°C using a furnace within the FlexiDry system. All treatments properly dried the corn below the target value of 15% dry basis moisture content (MD). The CHA and HA treatments yielded an average moisture extraction rate (MER) of 1.42 kg h-1, compared to 0.58 kg h-1 for the UA treatment. In terms of energy consumption, the specific moisture extraction rate (SMER) was 0.20, 0.44, and 1.11 kg kWh-1 for the UA, HA, and CHA treatments, respectively. The coefficient of performance (COP), i.e., the ratio between the theoretical heat delivered and the total energy consumed, was 0.14, 0.30, and 0.75 for the UA, HA, and CHA treatments, respectively. The FlexiDry treatments (HA and UA) consumed more energy than the CHA treatment, with more than 85% of the energy consumption used to regenerate the Drying Beads. The system yielded a global warming potential (GWP) of 0.931 and 0.425 kg CO2-eq kg-1 of water removed for the UA and HA treatments, respectively. These values are higher than the GWP of the U.S. corn industry drying standard, which is reported as 0.383 kg CO2-eq kg-1 water. Thus, if the regeneration process can be optimized, there is potential for reductions in energy intensity and GWP with large-scale, desiccant-based drying of agricultural commodities. Keywords: ,Dehydration, Energy, Food safety, Moisture, Regeneration.