Energy-saving drying of corn seeds

In the process of post-harvest processing of corn seeds, the thermal drying of wet cob is the most energy-efficient operation. It depends on the value of the produce ‒ the seeds and its competitiveness on the market. Today, the problem of energy saving becomes more relevant in connection with a significant increase in prices for energy materials, the cost of which is about 90% of all costs for the drying process. Different technical and technological methods of energy saving during drying of corn seeds, such as two-stage drying of cobs with pre-drying in grain, return of exhaust coolant to the drying zone (recirculation), application of the maximum allowable heating temperatures of the cavities (intensive drying) are investigated. The most practical value is the reversing and recycling of coolants, which reduce fuel consumption by 20‒26%, fully preserve the quality of the seeds, do not require significant technical re-equipment of chamber corn dryers. The new method of energy saving based on the use of TPG heat generators working from corn cobs burning is determined and investigated. The technical and technological indicators of the operation of chamber corn dryer in the complex with the new heat generator TPG are investigated. The temperature regime corresponded to normative parameters and fluctuated within 38‒43 °C. The ventilation regime under which the drying took place depended on the mode of access of air to the fuel and ventilation compartment. Full air access provided a specific airflow at the level of 1393 m3/h per 1 tonne of boilers satisfying the norm of 800‒1000 m3/h. Relative humidity of the working hot air during the entire drying process was 10‒12%. In experiments, the drying rate fluctuated within the range from 0.16‒0.39%/h, the performance of one chamber ‒ 1.2‒6.0 t-%/h, depending on the weight of the cobs, their humidity and exposure of drying. Drying on the energy-saving complex did not have a negative impact on the quality of corn seeds. Laboratory similarity of the studied hybrids was 95‒98%, which corresponds to normative indexes. The yield of seeds dried in the energy-saving complex was at the control level, and in some cases exceeded it. Control was provided by seeds dried in a laboratory dryer at 39 °C with forced circulation of air and in premises at 20‒25 °C. The economic efficiency of the new drying method is determined. The total cost of drying maize cobs with different types of fuel is diesel 1145 UAH/t, gaseous ‒ 665 UAH/t, corn cobs ‒ 250 UAH/t. In general, the use of new heat generators does not have any negative effect on the technological process of drying ‒ its duration, dynamics and uniformity of drying of the cobs