HOGEN Hydrogen Generator
HOGENs are rugged gas generators with a robust (PEM) cell stack and palladium membrane purification designed to run uninterrupted 24/7/365. Purge air monitoring and leak detection systems provide safe operation.
Adjustable 200 PSIG maximum delivery pressure is suitable for fuel gas and carrier gas for Fast GC. Automatic level control, water purity monitoring, and production control come standard for worry-free monitoring.
No caustic solutions or costly desiccant replacement necessary. The only maintenance required is to change the DI Water Resin Bag twice/year.
HOGEN Description of Operation
Deionized water flows into the anode where water electrolysis reaction 2H2O -> 4H- + 4e- + O2 occurs [1].
The oxygen is carried away by the water flow. The positively charged protons are attracted to the cathode using sulphonic acid ion groups embedded within the membrane as the path to travel through the solid material [2].
Simultaneously, the electrons flow through the power supply to the cathode [3] where it recombines with the emerging protons to form molecules of pure hydrogen gas [4].
Safe Operation with the HOGEN Hydrogen Generator
As an Environmental, Health and Safety professional, I am committed to providing our customers with products that are proven to be protective of human health and environmentally sound. Given that hydrogen is a flammable gas, safety is certainly a concern. Hydrogen generators are a safe way to utilize hydrogen in the laboratory. They are in fact safer than bottle hydrogen since hydrogen is generated upon demand. Below are some data points for EHS professionals to consider when buying a HOGEN gas generator.
–Jennifer Triplett, CHMM, Managing Director, Texol US LLC
Hydrogen Safety Design Standards for the HOGEN
Our safety certified HOGEN GC300 and GC600 hydrogen generators are the answer to reducing H2 inventory in the laboratory; see our brochure for specifications and certifications. Our HOGEN GC600 only has a maximum internal inventory of 0.25 grams of hydrogen at full operating pressure and can only produce hydrogen at its maximum generation rate when powered and not in a safe alarm mode.
The HOGEN is designed to preclude any issues with hydrogen when it is properly installed in a ventilated, non-classified area. It needs clean air for dilution and ventilation. It is not EX rated, so it should not be placed inside a classified fume hood or area. An open lab bench in a typical lab space is the appropriate location.
The following two points, with elaboration, describe our safety design for the HOGEN GC product:
1. The HOGEN box is ventilated with a fan at a rate that will dilute any leaked hydrogen to a safe level
A ventilation fan draws air from the bench top level and forces air to exit the top of the GC enclosure. This ventilation fan is rated at 35 CFM (Sunon KD1208PTB1) = 991089.6 cc Air/min.
Assume all the produced H2 leaks into the box. The HOGEN 600 gross hydrogen production is 4 cells * 28 amps * 7.52cc/cell-amp-min = 842 cc H2/min (The HOGEN 600 is rated to deliver 600 cc/minute pure hydrogen, and the balance is vented away with water vapor to regenerate the hydrogen purifier system inside the HOGEN).
The best case dilution of gross H2 production by maximum air ventilation is 842/991089.6 = 0.0849% H2 in air exiting the box.
Hydrogen design guidelines and hydrogen standards mandate no H2 concentration above the lower flammability limit of 4% H2 in air. This ventilation rate is 47 times what is needed to achieve this requirement.
H2 valves, fittings and vessels in the unit will all leak well before there is any risk of burst; all are proof pressure tested at 1.5x maximum allowable pressure. A relief valve release vents outside the box through the vent port in the event of any unintentional over-pressurization above 290 psig.
2. The ventilation air flow from the fan is constantly monitored and interlocked with H2 production:
Please refer to US Patents 6652732 B2 and 6524464 B2, fan flow sensor for proton exchange membrane electrolysis cell. An air flow sensing switch is configured in the GC product such that when insufficient air ventilation is sensed, the switch opens and causes the power to the electrolysis cell stack to stop; this event immediately causes the cell stack to cease H2 production. The fan switch will switch at below 20 CFM air, still well above the ventilation rate required according to the calculation above.
Certification: The HOGEN product is certified to UL/IEC 61010-1, a robust general standard that covers both electrical safety and associated hazards specific to our equipment, specifically combustible gases and the protective measures that we employ to mitigate potential hazards.