Hydrogen recovery from purge gas

Pressure swing adsorption (PSA) on zeolite molecular sieves (see Section 4.3.2.6) may be also used for hydrogen recovery from purge gas [761]. The process, originally developed by Union Carbide under the name HYSIV, is now marketed as Polybed PSA by UOP [970], [973], [974], PSA technology is also offered by Linde and other companies. If required, the process also offers the possibility to supply pure hydrogen from... 

The material efficiency of modern synthesis loops is very high hydrogen efficiencies of 98% can be achieved when hydrogen recovery from purge gas is included in the process. The remaining 2% of the feed hydrogen which is not converted to ammonia is utilized as fuel. 

---