Hydrogen generators are now becoming an essential component in many laboratories with greater gas consumption levels. Generators are considered to be preferable to cylinders, particularly because of the safety concerns about having high pressure hydrogen in the laboratory working environment. Hydrogen generator systems typically produce Hydrogen with a two-phase system. Hydrogen is first separated from water before being purified. Many Hydrogen generators utilize proton exchange membranes (PEM) coupled with a hydrogen purification systems such as Palladium-diffusion or Pressure Swing Adsorption (PSA).
Here we present four methods of hydrogen purification typically employed in Hydrogen generator systems. The first is a Combined Palladium Electrolyser/Purification System which produces high purity hydrogen through catalysed water electrolysis. The second method is the use of palladium-silver alloy diffusion membranes for Hydrogen purification. The last two methods of Hydrogen purification both involve Hydrogen separation using PEMs coupled with different drying systems. The first purification method involves coupling the PEM with use of PSA. The second involves PEM coupled with a silica desiccant system. This system simply involves passing the Hydrogen produced by the PEM through a silica gel column to remove moisture.
The relative merits of the four Hydrogen purification systems are discussed in terms of performance (purity of Hydrogen produced), durability, ease of use and cost.