To decrease the impurity levels of nitrogen oxides and low molecular weight hydrocarbons by purifying air supplied to a cryogenic air separation apparatus.
The nitrogen oxides and the low molecular weight hydrocarbons are removed from air by a temperature swing adsorption process using a combined zeolite adsorbent containing both zeolite-A and zeolite X as an adsorbent. This combined zeolite product is manufactured by forming a mixture of an agglomerate formed between silica and sodium zeolite having the Si/Al atomic ratio ranging ≥0.9 to <1.2 with water soluble sodium aluminate, keeping the mixture at a temperature ranging 25-100°C for a time enough to convert at least 50% of silica to zeolite A and ion-exchanging the resultant zeolite A- containing product at least partially with a 2-valent cation.
FITCH FRANK R
BULOW MARTIN
