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ARS Home » Plains Area » Manhattan, Kansas » Center for Grain and Animal Health Research » Stored Product Insect and Engineering Research » Research » Publications at this Location » Publication #398246
Research Project: Advancing Technologies for Grain Trait Measurement and Storage Preservation

Location: Stored Product Insect and Engineering Research

Title: Numerical simulation of phosphine movement in bulk-stored grain

Author
item ELSAYED, SHERIF - Kansas State University
item CASADA, MARK - US Department Of Agriculture (USDA)
item WEI, MINGJUN - Kansas State University
item MAGHIRANG, RONALDO - University Of Illinois
item MAIER, DIRK - Iowa State University

Submitted to: Journal of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/20/2023
Publication Date: 3/31/2023
Citation: Elsayed, S., Casada, M.E., Wei, M., Maghirang, R., Maier, D. 2023. Numerical simulation of phosphine movement in bulk-stored grain. Journal of the ASABE. https://doi.org/10.13031/ja.15378.
DOI: https://doi.org/10.13031/ja.15378

Interpretive Summary: Fumigation of bulk grain for stored product insect control requires detailed understanding of the behavior and movement of phosphine gas to maintain a lethal dosage everywhere and protect stored grain from subsequent insect damage. Phosphine gas moves slowly through the porous space in the grain mass due to diffusion and when carried by natural convection air currents and it leaves the pore space when adsorbed by the grain or when leaking from the storage container. Predicting the exact movement and subsequent dosage throughout the grain mass requires complex computational fluid dynamics (CFD) methods to simulate the movement of the gas due to all physical mechanisms that occur in the bulk grain. The CFD model developed and validated here accounted for effects of phosphine release locations, storage shape and orientation, leakage, sorption, diurnal fluctuation, and phosphine motion in three dimensions. Recommendations were developed to improve the distribution of phosphine in grain storage bunkers, and it was shown that diffusion and natural convection alone are not sufficient for spreading phosphine adequately within bunkers for maintaining a lethal dosage throughout.

Technical Abstract: Bunker storage is an inexpensive method for medium- and long-term storage of wheat. To control insect infestations in bunker storage, phosphine (PH3) fumigant, released from aluminum phosphide (AlP) tablets, is commonly used. For fumigation to be effective, a lethal concentration of PH3 throughout the bunker must be ensured. Because bunkers are exposed, temperature gradients are created throughout the bunker, resulting in natural convection currents that move PH3 from areas around the fumigation points to the entire bunker. This research used computational fluid dynamics (CFD) simulation to investigate the effect of natural convection on fumigation in bunkers. The model was validated against published benchmarks and a field experiment with a full-scale bin with sorption and leakage. The effects of PH3 release points location, bunker shape, bunker orientation, leakage, sorption, diurnal fluctuation, and PH3 motion in 3D were studied. Results agreed well with the experimental data and provide various recommendation for best management practices for PH3 fumigations in bunkers. Results showed that diffusion and natural convection solely are insufficient in spreading out PH3 within bunkers. Further research is needed on the effects of tarpaulin billowing in relation to PH3 behavior.