1. Closed Loop Fumigation of a Concrete Elevator Broken Arrow, Oklahoma
Dr. Carol Jones
Department of Biosystems and Agricultural Engineering
Oklahoma State University
Edmond Bonjour and Randy Beeby
Stored Products Research and Education Center
Department of Entomology and Plant Pathology
Mark Fultz, Manager
Hansen Mueller Grain Co., Broken Arrow, Oklahoma

2. Urbanization around Rural Elevator

3. Challenges
Fumigation safety is a concern to neighbors and to employees
Conventional methods of phosphine fumigation put workers and people in close proximity in danger
Improper fumigation leads to insect resistance

4. Goals of this Project
Seek a method to improve safety of fumigating with phosphine
Seek a method to decrease the amount of fumigant required
Seek a method to increase the concentration distribution throughout the grain bins

5. Common Fumigation Methods and Negative Effects
Probe and Tarp: exposure during tarping
Automatic Dispenser: pellets spill from buckets and release gas in unwanted areas, shrinkage caused from turning and moving grain
Gravity Fumigation: little control of where gas may go
Each method offers increased risk of exposure during insertion of fumigant into the grain.

6. Proposed Method Closed Loop Fumigation System in a concrete silo
Example of a J-System patented by James Cook in 1980.
Consists of:
Sealing air leaks in storage structure
Installing low pressure low volume centrifugal blower re-circulating air-gas mixture from headspace of grain into base of silo
Installing pipes from fan to blower and back into silos

7. Closed Loop Basic Idea
Pressured base ducts force gas mixture upward through grain bulk providing better gas distribution through grain.
Headspace
Grain Bulk
Blower

8. Bin Diagram of Elevator Facility

9. Closed loop system installed in one half of the elevator while the other half remained unchanged for a conventional method fumigant application
Conventional
CLF
8660 MT capacity
(120,000 bu)

10. Dosage: Phosphine Pellets
Manager chose his normal dosage rate of 500 pellets/1000 ft3 which is his normal dosage rate. Both sides of the elevator were treated the same.
CLF side: pellets distributed on top of the grain.
Conventional side: pellets were inserted into the grain as it was loaded into the bin

11. Monitoring
Monitoring fumigation: top, bottom, and middle of bin

12. Monitoring
Electronic gas meters were used to measure phosphine concentration every 4 hours for the first 32 hours and every 10 hours for the next 88 hours.

13. Results
CLF BIN
CONVENTIONAL BIN
200 PPM

14. A closed loop system was installed in one half of the elevator while the other half remained unchanged for a conventional method fumigant application
Conventional
CLF
8660 MT capacity
(120,000 bu)

15. Installation of CLF
Bin Diagram of Elevator Facility
Seal Inner Vents

16. Installation of CLF
Seal silos as completely as possible…inner vents to silos not included in loop

17. Installation of CLF
Bin Diagram of Elevator Facility
Seal Outer Vents

18. Installation of CLF
Seal silos as completely as possible…outer vents

19. Installation of CLF
Seal silos as completely as possible...access openings

20. Proposed Method for Study
Bin Diagram of Elevator Facility
Headhouse
Install Fan on top of Bin 6 (outside of head house)

21. Proposed Method for Study
Blower mounted outside on top of one bin adjacent to the head house.
1/3 HP supplying 320 cfm

22. Proposed Method for Study
Installing pipes from fan to blower and back into silos
Down man lift shaft to ground level using 3 inch PVC sewage pipe
Flexible hose from fan through window to man lift shaft

23. Proposed Method for Study
Installing pipes from fan to blower and back into silos

24. After Fumigation
Blower discharge piping was disconnected and the blower was used to evacuate the fumigant from the CLF system and bins.
Evacuation can be accomplished when the danger to workers or to residents around the elevator is the least.
Gas can be discharged 120 ft. above ground level reducing danger

25. Closed Loop Fumigation Conventional Fumigation
Installation costs
Less fumigant
Less labor
Less worker exposure and health costs
Conventional Fumigation
Turning costs and product shrinkage
More fumigant
More labor
More bin entry required of workers causing health risk and higher insurance rates

26. Economic Comparison ($4/bu wheat)

27. Economic Comparison ($8/bu wheat)

28. Conclusion
Closed loop fumigation was more successful since it reached the desired 200 ppm for 100 hours. Conventional fumigation did not reach this level.
¾ of the fumigant could have been saved in this elevator
Closed loop fumigation is ultimately cheaper
Closed loop fumigation is safer than conventional fumigation when carried out properly

29. Closed Loop Fumigation of a Concrete Elevator Broken Arrow, Oklahoma
Dr. Carol Jones
Department of Biosystems and Agricultural Engineering
Oklahoma State University
Edmond Bonjour and Randy Beeby
Stored Products Research and Education Center
Department of Entomology and Plant Pathology
Mark Fultz, Manager
Hansen MuellerGrain Co., Broken Arrow, Oklahoma