Superheated steam drying and processing of biological materials.

传统热风干燥耗能大，约占大多数工业国家工业能耗的15%。减少能源消耗和与之相关的二氧化碳排放的途径将取决于突破性技术。过热蒸汽是在一定压力下温度高于饱和点时产生的干蒸汽。SS干燥是传统热风干燥的一种新的替代方法，因为它提供了更高的效率、更高的干燥速度、更少的排放和更好的安全性。由于该技术符合能源效率和低环境影响的新趋势，因此对于从颗粒(例如木材颗粒、燕麦格子、褐煤)到泥浆(例如生物质、废谷物、鱼粉)的干燥材料来说，它正成为一种越来越有吸引力的替代方案。干燥泥浆具有挑战性，可以通过回收干产品作为惰性材料并将其与湿材料混合来解决。这需要对干燥过程中不断变化的材料特性进行系统的探索。因此，了解被干燥材料和干燥SS介质之间的动态相互作用是至关重要的。本研究项目将建立一个数学模型，描述再生干料惰性芯上的浆料在固相中的干燥，并将确定固相参数对材料在静态和动态条件下物理完整性的影响。 从当地酿酒厂获得的蒸馏液将被分成可溶部分和粗略部分。粗料将被压实成各种形状(圆柱体和圆盘)，并在SS中烘干。然后，它将作为惰性的干燥材料。浆料(由粗组分和可溶物组成)将被沉积在致密的惰性材料上，然后在不同的温度和SS的速度下干燥。所记录的压坯和沉积浆料的水分和温度变化将是建立双层材料在SS中干燥的数学模型的基础。数值技术将被用来开发一个数学模型，解决颗粒大小对水分扩散率的影响。压坯在SS中干燥过程中的物理性能变化将通过实验确定并以数学形式描述。 SS已成功地用于食品和非食品的干燥，与传统的干燥机相比，大大减少了干燥时间和干燥机的尺寸。对惰性回收材料上的SS干燥进行建模，并将该信息与材料的性质联系起来，将提供关于干燥过程的深入知识，这对加工者和设计工程师来说是非常重要的。

Conventional hot-air drying is energy intensive and accounts for about 15% of the industrial energy consumption in most industrial countries. The path to reduced energy consumption and associated with it CO2 emissions will depend on breakthrough technologies. Superheated steam (SS) is dry steam which is produced when its temperature is above the saturation point at a given pressure. SS drying is a novel alternative to conventional hot-air drying as it provides increased efficiency, higher drying rates, reduced emissions and improved safety. Since the technique complies with the new trend toward energy efficiency and low environmental impact, it is becoming an increasingly attractive alternative for drying materials that range from granules (e.g., wood granules, oat groats, brown coal) to slurry (e.g., biomass, spent grain, fish meal). Drying slurries is challenging and can be solved by recycling dry product as inert material and mixing it with wet material. This requires systematic exploration of material properties that continuously change during drying. Therefore, an understanding of the dynamic interaction between the material being dried and the drying SS medium is critical. This research program will develop a mathematical model describing drying in SS of slurry on an inert core of recycled dry material, and will determine the effect of SS parameters on material’s physical integrity in static and dynamic conditions. Stillage obtained from a local distillery will be separated into soluble and coarse fraction. The coarse fraction will be compacted to various shapes (cylinders, and disks) and dried in SS. It will then serve as the inert dry material. The slurry (a composition of the coarse fraction and solubles) will be deposited on the compact inert material and then dried in various temperatures and velocities of SS. The recorded moisture and temperature changes of the compact and the deposited slurry will be the basis for developing mathematical models of drying in SS of the two-layer material. A numerical technique will be used to develop a mathematical model addressing the effect of particle size on moisture diffusivity. Changes in physical properties of the compacts over the course of drying in SS will be determined experimentally and described mathematically. SS has been successfully used in drying of food and non-food products substantially reducing the drying time and size of driers when compared to conventional dryers. Modelling of SS drying on an inert- recycled material and linking that information to materials’ properties will provide in-depth knowledge on the drying process that will be essential to processors and design engineers.