On-Site Hydrogen Generation through water electrolysis is a great way of transforming low cost electricity into hydrogen gas that can be used in a variety of applications. Hydrogen fueling and many industrial applications have high storage and process pressures that require compressed hydrogen gas. The main reason why compression is necessary when using hydrogen as an energy carrier is because hydrogen is the lightest gas in the universe and when hydrogen gas is at atmospheric pressure the molecules are far apart making it harder to fit many hydrogen molecules in a small container. This is important because hydrogen storage tanks in fuel cell cars require pressures up to 10,000 psi when full.
Conventional methods of compression involve specialty mechanical piston driven hydrogen compressors. These hydrogen compressors can be expensive and energy intensive because they need to be built with extremely low tolerances, and work harder to compress hydrogen gas because of hydrogen’s extremely small molecular size and weight. Mechanical compressors also require lubrication that could potentially contaminate the hydrogen gas downstream. The downstream filtration of hydrogen gas can lead to further costs.
Electrochemical compression an alternative to conventional hydrogen compressors uses a Proton Exchange Membrane PEM surrounded by membrane electrode assemblies to draw low pressure hydrogen through the PEM membranes to compress hydrogen gas without the use of mechanical compression methods. Trade studies of electrochemical compression have shown that the technology is competitive in cost and efficiency with mechanical compressors, and could potentially be a more efficient means of compressing hydrogen in the future. Today electrochemical hydrogen compressors can compress hydrogen gas up to 5,000 PSI, and with further research and development efforts the technology has the potential to compress hydrogen beyond 10,000 PSI. This technology will enable hydrogen generators to generate and compress hydrogen for fueling applications without an external compressor thus improving the energy conversion rate and cost of compressed hydrogen.
The commercial PEM hydrogen generators offered by Proton utilize electrochemical compression to generate hydrogen at pressures up to 435 PSI. Many applications that require light compression will benefit from using Proton PEM hydrogen generators because if the pressure requirement does not exceed 435 PSI, the process will not require external compressors. This saves customers money, and improves process energy efficiency. To learn more about Proton PEM technology visit http://www.protononsite.com/our-technology.