Design and construction of a helium purification system using cryogenic adsorption process

One of the most appropriate methods for elimination of trace impurities in helium is cryogenic adsorption process. Therefore, in this study, design and construction of cryogenic adsorption helium purification system (3 Nm^3.h^-1, 80 bar) was carried out using activated carbon as an adsorbent at 77 K. For evaluation of adsorption dynamics and effect of pressure on elimination of trace impurities, helium purification was performed from 10 to 70 bar. Results showed that helium can be purified from 99.95 % to 99.99999 % at pressure of 60 bar using a cryogenic adsorption process. Effect of regeneration condition on helium purity and recovery was investigated by three different regeneration methods: regeneration by helium at 40 °C and at 180 °C as purge gas, countercurrent to feed direction, and regeneration via vacuum. Results showed that regeneration of bed by vacuum could be proposed as the most appropriate method because of maximum helium purity and high recovery of helium (98 %).