Large Commercial-scale Grain Bulk Fumigation with Cylinderized Pure Phosphine Coupled with the Nitrogen Generator System

Phosphine is a major fumigant for insects control in stored products. However, the current fumigation with aluminum phosphide to generate phosphine is facing many challenges, such as require manual operation, fumigation produce can’t be automatically performed, and management of residue contaminants. To address these issues, the study utilizes a combination of pure phosphine gas from cylinders and nitrogen from a membrane separation nitrogen generator. Phosphine and nitrogen are mixed at predetermined ratios, and the resulting gas mixture is delivered directly into sealed grain storage facilities via a controlled release device and circulated within the grain piles to ensure fumigant evenly distribution. This maintains effective phosphine concentrations within the storage facility. The exposure duration lasted for 13 days, during which phosphine concentrations were monitored, and the total mortality rate of adult insects within the grain piles was recorded. Within 9 hours of treatment initiation, gas concentrations reached 736 mL/m3, peaking at 1 160 mL/m3, with an effective average concentration above 200 mL/m3 sustained for 10 days. The gas circulated and distributed uniformly within the treated space, enabling effective control of major stored commodity pests within a relatively short exposure period.