Real-time Monitoring of Drying Parameters in Semi-Trailers during Peanut Drying

Abstract

Abstract. The efficient control of drying parameters is essential to ensure that peanuts are dried at the optimal rate, preserving quality and desired flavor. The present peanut drying process has limitations in means for measuring parameters such as temperature and relative humidity of the air being blown into and exhausted from the peanuts in real-time or in a discrete manner. A sensor network, with an embedded microcontroller, consisting of relative humidity and temperature sensors and a microwave moisture sensor was developed to monitor such drying parameters in real-time. A previous version of the sensor network was field tested during the 2013 peanut harvest season, and positive results were observed. Drying parameters were measured and stored on a CompactFlash card every 12 seconds. In-shell kernel moisture content was determined with a standard error of prediction of 0.55% moisture when compared to the reference oven-drying method. After the addition of more sensors, two sensor networks were deployed during the 2014 peanut harvest season at a peanut buying station in central Georgia. They were placed in the 45-ft drying semi-trailers with one near the front of the trailer and the other near the back of the trailer. At both locations, pod and kernel moisture content, temperature of the drying peanuts, temperature and relative humidity of the air exhausted from the peanuts, and temperature and relative humidity of the air being blown into the peanuts were measured in real-time. Data from measurements at the two locations within each semi-trailer were time-stamped and used to assess the uniformity of peanut drying. Results show promise for the development of a system to monitor and control drying parameters in the field in real-time. Such a system has the potential for saving a buying station on average $22,000/year in propane and electric energy costs.