Drying peanuts in a modified hopper-bottom trailer: Evaluating drying performance

Authors: TEDDY, BRENNAN - Clemson University; TURNER, AARON - Clemson University; KIRK, KENDALL - Clemson University; FOGLE, BENJAMIN - Clemson University; McIntyre, Joseph; Butts, Christopher - Chris

Submitted to: Proceedings of the American Society of Agricultural and Biological Engineers International (ASABE)
Publication Type: Proceedings
Publication Acceptance Date: 3/29/2021
Publication Date: N/A
Citation: N/A

Interpretive Summary: Computer software to simulate airflow in confined spaces was used to design modifications to hopper-bottom trailers so that peanuts could be dried prior to marketing. A 42-ft hopper-bottom trailer was modified based on the simulated designs. A conventional peanut drying fan was connected to the front of the trailer using a round flexible duct and transition. The heated air was forced into the space formed by the front and sidewalls of the trailer and the front hopper. Air moves from the front pressure chamber through an opening in the bulkhead for the front hopper and into the space below the tarp used to cover the trailer. Air traveled the length of the trailer between the tarp and the top surface of the peanuts and then down through the peanuts. Humid air exhausted through vents installed in the front and rear-facing panels of the hopper tubs. After drying, there was a moisture gradient from the top surface to the peanuts in the bottom of the tubs. Moisture was higher in the bottom of the tubs and lower at the top surface of the peanuts. Moisture was approximately the same in the front and rear hoppers. The design process is documented in a separate paper, ASABE Paper No. 2100527.

Technical Abstract: Hopper-bottom trailers retrofitted for peanut drying could provide several advantages to producers and peanut buying point operations. Producers who utilize hopper-bottom trailers for transporting grain would have an additional use for the trailer and would be less prone to harvest delays during peak times when trailer availability from the buying point is limited. Additionally, smaller buying points would benefit from reduced handling steps and dependency on trailer lifts. Thus, the objective of this study was to evaluate the potential of drying peanuts directly on a modified hopper-bottom trailer. Multiple test loads of peanuts were dried on the hopper bottom trailer during the 2020 season, and hand samples were collected from multiple locations throughout the peanut mass at intervals throughout the drying process to assess drying uniformity. Additionally, instrumentation was installed at several locations in the peanut mass, at the air inlet, and outlets to monitor temperature and relative humidity throughout the drying process. Preliminary results of a sample load indicated a moisture content decrease from 12.9% w.b. to 12.0% w.b. after 8.5 hours of drying time. Average moisture content was reduced further to 11.1% w.b. following an additional 8.6 hours after the dryer was shut off. The official grade sample moisture was 9.1% w.b. and was consistent with the observed moisture gradient existing from the top to bottom of the trailer. Trailer modification and CFD modeling is presented in another companion paper (McIntyre, et al. Drying Peanuts in a Modified Hopper-Bottom Trailer: CFD Modeling and Design, ASABE Paper No. 2100527).