Microprocessor controlled low-temperature corn drying system
Abstract Hardware, software and control criteria of microcomputer control of low-temperature corn drying are discussed. The ambient temperature and relative humidity were monitored by the microcomputer as a measure of the input conditions. A model of the low-temperature drying process stored in the memory enabled the microcomputer to calculate the grain moisture contents at assigned locations in the bin. Control decisions were then based on predicted moisture levels and on predicted or measured grain temperatures. Simulation results showed that the proposed system can save energy from 5 to 31% compared with high-temperature drying, depending upon the weather conditions.
A THIN-LAYER DRYING MODEL FOR PADDY DRYER
Precision control of drying conditions is very important in conducting thin-layer drying experiment on agricultural products. For control of drying it is necessary to determine drying kinetics, and obtain the moisture change during the drying process. In order to carry out the experiments a generalpurpose fully automated thin-layer dryer was designed and tested. Experiments on the drying kinetics of paddy (Fajr variety) were conducted at five drying air temperatures, ranging from 30 to 70 C o , in four air velocities, ranging from 0.25 to 1.0 m/s. During the drying the mass loss of samples measured continuously with a digital balance. Drying curves obtained from the experimental data were fitted to nine thin layer models. Results showed that two-term model predicts moisture change in drying with higher accuracy than other models.
Peanut Drying Energy Consumption
Abstract Total energy consumption and drying times were determined for drying peanuts with various equipment and procedures commonly used by the peanut industry. Total peanut drying times were significantly shorter with 3.73 kW, single-trailer (ST) dryers than with 7.46 kW, double-trailer (DT) dryers. Total energy consumption was significantly higher per tonne of peanuts dried for drying with ST dryers. Total energy consumption and drying times were not significantly different for drying in side-air-entry or rear-air-entry trailers. Precleaning reduced energy requirements for drying and slightly reduced total drying times. Drying peanuts at 40.56°C decreased drying times but required considerably more energy than drying at 35°C. Type of temperature control, constant (Co) or cycling (Cy), had no effect on drying times or energy consumption.