Technological basics of integrated grain drying and storage systems

The paper reviews objectives of integrated drying and storage of agricultural seeds. Among the topics discussed are: decreasing moisture content of seeds to safe levels; cooling dried grain to ambient conditions; cleaning seeds before and after drying. The study presents comparative analysis of natural air drying, low-temperature drying, drayage and combined drying. It also demonstrates reasonability of using of grain mass stirring devices and biomass energy in plants for integrated seed drying and storage. The design and technological classification of seed convective drying methods is presented. The process of seed convective drying in thick layer is rationalized. The study determines seed layer-by-layer moisture content during convective seed drying in a thick layer. The main criteria to be considered are grain quality, energy efficiency, capacity, operating costs, and farmer expertise. Integrated seed drying and storage systems lead to improved grain quality compared to high temperature drying. Natural air drying produces the best quality (if properly operated), and needs the least amount of energy. However, its capacity is low and it requires the most attention and expertise of farmers. The strategies for controlling fans and heaters for bulk or aerated seed drying are presented.