Closed Loop Fumigation of a Small Rural Concrete Elevatorin a Growing Urban Setting2008 C. A. F. Conference, Chengdu, ChinaSept. 21 - 28Dr. Carol JonesDepartment of Biosystems and Agricultural EngineeringOklahoma State UniversityEdmond Bonjour, Dr. Tom Phillips and Randy BeebyStored Products Research and Education CenterDepartment of Entomology and Plant PathologyOklahoma State UniversityMark FultzHansen Mueller Co.Dr. Ron NoyesGrain Storage Engineering, LLCGeography2008 C. A. F. Conference, Chengdu, ChinaSept. 21 - 28OklahomaBroken ArrowUrbanization around Rural Elevator2008 C. A. F. Conference, Chengdu, ChinaSept. 21 - 28Challenges• Urbanization makes elevator managers more aware of safety measures• Fumigation safety is a concern to neighbors and to employees• Conventional methods of phosphine fumigation put workers and people in close proximity in danger2008 C. A. F. Conference, Chengdu, ChinaSept. 21 - 28Goals 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 bins2008 C. A. F. Conference, Chengdu, ChinaSept. 21 - 28Common 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 goEach method offers increased risk of exposure during insertion of fumigant into the grain. 2008 C. A. F. Conference, Chengdu, ChinaSept. 21 - 28Proposed Method for Study• 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 silos2008 C. A. F. Conference, Chengdu, ChinaSept. 21 - 28Proposed Method for StudyPressured base ducts force gas mixture upward through grain bulk providing better gas distribution through grain.2008 C. A. F. Conference, Chengdu, ChinaSept. 21 - 28Grain BulkHeadspaceBlowerProposed Method for StudyBin Diagram of Elevator Facility2008 C. A. F. Conference, Chengdu, ChinaSept. 21 - 28A closed loop system was installed in one half of the elevator while the other half remained unchanged for a conventional method fumigant application2008 C. A. F. Conference, Chengdu, ChinaSept. 21 - 28CLFConventional8660 MT capacity(120,000 bu)Proposed Method for Study• First Step: Seal silos as completely as possible…inner vents2008 C. A. F. Conference, Chengdu, ChinaSept. 21 - 28Proposed Method for Study• First Step: Seal silos as completely as possible…outer vents2008 C. A. F. Conference, Chengdu, ChinaSept. 21 - 28Proposed Method for Study• First Step: Seal silos as completely as possible...access openings2008 C. A. F. Conference, Chengdu, ChinaSept. 21 - 28Proposed Method for Study• Blower mounted outside on top of one bin adjacent to the head house.• 249 W (1/3 HP) supplying 0.15 m3/s (320 cfm)2008 C. A. F. Conference, Chengdu, ChinaSept. 21 - 28Proposed Method for Study• Installing pipes from fan to blower and back into silos2008 C. A. F. Conference, Chengdu, ChinaSept. 21 - 28Proposed Method for Study• Installing pipes from fan to blower and back into silos2008 C. A. F. Conference, Chengdu, ChinaSept. 21 - 28Proposed Method for Study• Monitoring fumigation: top, bottom, and middle of bin2008 C. A. F. Conference, Chengdu, ChinaSept. 21 - 28Proposed Method for Study• Dosage: Manager chose his normal dosage rate of 17 pellets/m3which 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 bin2008 C. A. F. Conference, Chengdu, ChinaSept. 21 - 28Proposed Method for Study• 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.2008 C. A. F. Conference, Chengdu, ChinaSept. 21 - 28Results2008 C. A. F. Conference, Chengdu, ChinaSept. 21 - 28CLF versus Conventional Fumigation050010001500200025000 1020304050607080Hour from TreatmentppmCLF BINCONVENTIONAL BIN200 PPMAfter 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 35 meters above ground level reducing danger2008 C. A. F. Conference, Chengdu, ChinaSept. 21 - 28Economic Comparison• Closed Loop 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 rates2008 C. A. F. Conference, Chengdu, ChinaSept. 21 - 28Economic Comparison ($4/bu wheat)2008 C. A. F. Conference, Chengdu, ChinaSept. 21 - 28Economic Comparison ($8/bu wheat)2008 C. A. F. Conference, Chengdu, ChinaSept. 21 - 28Conclusion• 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 properly2008 C. A. F. Conference, Chengdu, ChinaSept. 21 - 28Closed Loop Fumigation of a Small Rural Concrete Elevatorin a Growing Urban Setting2008 C. A. F. Conference, Chengdu, ChinaSept. 21 - 28Dr. Carol JonesDepartment of Biosystems and Agricultural EngineeringOklahoma State UniversityEdmond Bonjour, Dr. Tom Phillips and Randy BeebyStored Products Research and Education CenterDepartment of Entomology and Plant PathologyOklahoma State UniversityDr. Ron NoyesGrain Storage Engineering,
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