The Degesch Phosphine Generator

The newly developed Degesch America, Inc.  Phosphine Generator is a device for manufacturing hydrogen phosphide (phosphine) from outside of a fumigated structure.  Its phosphine producing capabilities are limited only by the certified operator.

Magnesium Granules are applied into a sealed chamber inside the machine and hydrolyzed with water to produce phosphine gas under controlled atmospheres.  During the process the PH₃ being produced is mixed with an air-carbon dioxide hydrogen phosphide mixture that is exchanged with air inside the sealed structure via an internal recirculation fan.  By taking air out of the structure being fumigated and exchanging it with the air-gas mixture, pressure changes inside the structure are negligible.  This process of exchanging the air aids in the rapid distribution of high concentrations of phosphine.

The generation of the PH₃ gas mixture can be regulated from 0.0% to 2.5% v/v.  When the concentrations are below 1.8%v/v the mixture cannot self-ignite.  The process of applying carbon dioxide during the generation of PH₃ with the DAI Phosphine Generator ensures the gas mixture cannot self ignite above the 1.8% v/v level.  The DAI Generator will produce a PH₃ gas mixture equivalent to that produced by 3,700 tablets of ALP per hour.

The Generator is operated by a touch screen computer board.  Once programmed, the machine is designed to operate automatically (with the exception of reloading the magnesium granules) until the desired results have been achieved.  Although the machine is fully automated, the certified operator can manually control several functions.  For example, production of PH₃ can be paused, stopped completely or started again at any desired moment by the certified operator.  Numerous valves and controls can be manually checked for operational status via the control board at any time during the process.

Several items are needed to make the DAI Generator functional.  They are a 110 volt electrical supply, a continuous water flow, a cylinder of carbon dioxide (one 90kg cylinder will be sufficient enough to produce 40kg of magnesium granules), an air supply (whether it be a recirculation supply line from the fumigated structure or ambient supply), and magnesium granules.

Although the new DAI Generator was developed to operate automatically, it cannot be operated without the presence of at least two trained, certified operators.  The machine has many built in safety features that will automatically stop production of the PH3 gas mixture in the event that the controlling parameters become insufficient. The machine will automatically stop production if there is insufficient or excess air, water or carbon dioxide supply.  The Generator will also stop production if there is a malfunction in the power supply, flow of hydrogen phosphide or the temperature inside the machine becomes too high.  In any of these scenarios, an audible alarm will sound and the machine will stop production immediately until the problem is solved.  For this reason, it is important that the machine not be left unattended by the certified operator.  In the event the machine incurs a critical alarm, the machine automatically closes several production valves inside and opens others to flush the entire Generator with CO₂.  This additional safety feature prevents any damage from occurring to the machine during a critical alarm period.

What are some of the advantages of the DAI Phosphine Generator?

1. Hydrogen phosphide does not need to be physically applied or removed from the structure by trained personnel.

2. Quick production of high concentrations of PH₃ may result in shorter fumigation periods. 

3. PH₃ concentrations can be increased during the fumigation period. 

4. Fewer certified applicators and less safety equipment are required to apply the fumigant using the DAI  Generator . 

5. It is no longer necessary to enter a fumigated structure to add back fumigant. 

6. Ambient temperatures and relative humidity no longer have an effect on how PH₃ is generated. 

7. It is safer for the operator in the fact that he/she will never touch the fumigant.  The fumigant is introduced into the    machine via a sealed flask similar to the tablet flask.

8. Wet or dry deactivation of the fumigant is no longer needed.

9. Phytotoxicity is no longer a concern. 

10. Fire hazards are no longer a concern.  The air-carbon dioxide-hydrogen phosphide gas mixture is non- flammable when regulated to less than 1.8% v/v.

11. The end product (magnesium carbonate) generated by the production process contains less than .001% un-reacted material and therefore may be put into sanitary drain.
12. Environmental hazards are no longer a concern because the PH₃ being produced is readily deactivated by sunlight when exposed to the atmosphere.
13. Multiple silo fumigations can be conducted from one central location using a gas distribution manifold system.
14. Pressure increases within a fumigated structure are no longer a concern because the air is exchanged within the machine via a recirculation pump.
15. Only two kilograms of magnesium granules are needed to produce 1 kilogram of PH₃.