Using a Microwave Sensor to Monitor Shrinkage Within an Eighth-scale Grain Drying System in Real-time

Authors: Lewis, Micah; Trabelsi, Samir

Submitted to: ASABE Annual International Meeting
Publication Type: Proceedings
Publication Acceptance Date: 6/1/2023
Publication Date: 7/10/2023
Citation: Lewis, M.A., Trabelsi, S. 2023. Using a microwave sensor to monitor shrinkage within an eighth-scale grain drying system in real-time. ASABE Annual International Meeting. https://doi.org/10.13031/aim.202300929.
DOI: https://doi.org/10.13031/aim.202300929

Interpretive Summary:

Technical Abstract: Drying of agricultural commodities is a necessary, post-harvest task performed to avoid degradation of quality and ensure safe storage for prolonged periods of time. During drying, heat and mass transfer phenomena occur simultaneously as moisture is removed from the product. As moisture is removed, the mass and volume of the product decrease as well, affecting the density of the bed of drying material. The decrease in volume of the product during drying is known as shrinkage. Shrinkage can affect the product’s test weight and other parameters that help assess its value. It is normally determined at the end of drying once a final moisture content is known or estimated at the beginning of drying based on the target final moisture content. However, real-time determination of shrinkage would be helpful in monitoring the product’s quality and providing a mechanism to minimize overdrying. Knowledge of the product’s moisture content in real-time would provide a way to determine shrinkage in real-time. Therefore, a microwave sensor was used to determine the moisture content of wheat in real-time as it dried within an eighth-scale grain drying system. The microwave sensor has a standard error of performance (SEP) = 0.55%. A 60-cm high, 153,106-cm3 bed of wheat was dried to different final moisture contents to assess the determination of shrinkage under various conditions. Moisture content as well as other parameters were determined with 12-s resolution throughout the drying process. For the different drying trials, shrinkage was observed as it reached final values from 7 to 10.1% of the original volume. Such shrinkage values equate to losses in mass of 7.3 to 10.5 kg, respectively from the 104-kg bed of wheat. The expected correlation between shrinkage and moisture content was also observed by using the microwave sensor to determine each in real-time.