Storing peanuts in grain bags

Authors: Butts, Christopher - Chris; WARD, JASON - Agco Corporation

Submitted to: Applied Engineering in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/15/2021
Publication Date: 2/1/2022
Publication URL: https://handle.nal.usda.gov/10113/7709309
Citation: Butts, C.L., Ward, J. 2022. Storing peanuts in grain bags. Applied Engineering in Agriculture. 38(1):93-102. https://doi.org/10.13031/aea.14475.
DOI: https://doi.org/10.13031/aea.14475

Interpretive Summary: Farmers’ stock peanuts and shelled oil stock peanuts were loaded into grain bags typically used for short term storage of small grains such as wheat, corn, and soy beans. The objectives of this study were to evaluate the suitability of existing equipment for loading and unloading peanuts into/from the bags; determine the capacity of the bags, and how well peanuts can be stored in the bags. In May 2015, dry farmers’ stock peanuts from the 2014 crop were used to fill two 9-ft diameter grain bags. It required 2.8 ft per ton of farmers’ stock peanuts. The first bag was unloaded using a pneumatic vacuum system to unload the first bag after being stored for 30 days. The second bag was unloaded using a skid steer loader after 60 d storage. Moisture migration and subsequent condensation caused a layer of high moisture peanuts to form in the top of both bags making all the peanuts in the bags unsuitable for human consumption. The value decreased from $342/ton to $125/ton, a reduction of 63%. The gravity flow equipment used to load the farmers’ stock peanuts and the vacuum extractor performed satisfactorily. When unloading the second bag with the vacuum extractor, operator error caused a severe clog, and the remainder of the bag was unloaded using a skid steer loader. In the second part of the test, shelled oil stock peanuts were loaded into grain bags for storage. The gravity feed bag filling equipment loaded the bags satisfactorily. The bags required 1.6 ft per ton of oil stock peanuts. The oil stock peanuts were stored for 60 d. Peanut quality was satisfactory at the end of the 60 day trial with no moisture migration observed. However, due to the inability of the oil stock peanuts to flow freely, the conventional bag extractor did not work and a skid steer loader was used to unload both oil stock bags. Based on these studies, storing farmers’ stock or shelled oil stock peanuts in grain bags is not recommended.

Technical Abstract: Edible grade farmers’ stock peanuts and shelled oil stock peanuts were stored in hermetically sealed silo or grain bags to determine their suitability for short-term storage. The objectives of the study were to evaluate equipment for loading and unloading the grain bags, the capacity of the grain bags, and the changes in quality. In May 2015, approximately 90 Mg of farmers’ stock (in-shell) peanuts from the 2014 crop were unloaded from a commercial warehouse, transported to Dawson, Georgia, and loaded into two 2.7 m diameter grain bags. Similarly, 85 Mg of shelled oil stock peanuts were loaded into two 2.7 m diameter grain bags. Farmers’ stock bags were unloaded after 30 and 60-d storage. A vacuum extractor and a skid steer loader were used due to wet peanuts in the top of the bag. Both oil stock bags were unloaded after 60-d storage. A skid steer loader was used to unload the oil stock bags because shelled oil stock peanuts did not flow adequately to use the conventional bag extraction equipment. Oxygen content in the farmers’ stock peanuts decreased from ambient levels (21%) to an average of 8.6% after 15-d storage. After 20-d storage, the oxygen content in the oil stock had decreased to 14%. A layer of high moisture peanuts due to moisture migration and subsequent condensation in the top of both of the farmers’ stock bags resulted in the peanuts being unsuitable for human consumption and reduced the value from $342/Mg to approximately $125/Mg for oil stock, a 63% reduction in value. No moisture problems were observed in the oil stock bags when they were unloaded. Based on these studies, sealed grain bags would be unsuitable for temporarily storing farmers’ stock peanuts under typical Georgia conditions. Sealed grain bags could possibly be used to store oil stock peanuts for 60 d, but suitable unloading equipment would have to be found or developed.