Gas mixt. contg. hydrogen and nitrogen for ammonia synthesis - where hydrogen is purified in adsorbers which are desorbed by nitrogen, and some nitrogen is left in adsorbers

摘要

A first gas mixt. contg. hydrogen and adsorbable impurities is fed through at least one adsorption bed to remove the impurities and obtain a gas rich in H2, which is fed through a second bed at a lower pressure. Nitrogen gas is then fed in the reverse direction through the first bed to remove the impurities by desorption. Some N2 is intentionally left in the first bed, and is compressed together with more gas. After further adsorption of the impurities, a prod. gas mixt. of H2 and N2 is obtd. The pref. plant uses a row of adsorber beds and alternating gas pressures; and the N2 required is pref. obtd. by the cryogenic treatment of air. The O2 obtd. from the air is pref. used in mfg. gas. Increased yield of H2, and lower energy consumption is provided.