Use of physical adsorption to facilitate the production of high purity oxygen

Abstract

An experimental study, related to the adsorption of carbon dioxide impurities (in oxygen) on a Linde type 5A molecular sieve, has been described. The adsorption process was studied dynamically using laboratory scale apparatus. Operating parameters were selected to simulate, as nearly as possible, the conditions normally employed during the operation of a large scale adsorption type purifier. These conditions were ca. 7.8 atm (total carbon dioxide and oxygen gas pressure) and 20°C throughout all experimental trials. Although carbon dioxide impurity levels were nearly constant throughout each adsorption run, the overall range in carbon dioxide impurity levels (in oxygen) varied between ca. 10 and 50 ppm from trial to trial. Therefore, the carbon dioxide adsorption capacity of the 5A molecular sieve was determined as a function of varying and very low carbon dioxide concentrations in the presence of relatively high concentrations of oxygen. Employing the techniques described in this paper, carbon dioxide impurity concentrations in oxygen were reduced from levels exceeding 50 ppm in the original source of oxygen to less than 25 ppb in the purified gaseous oxygen.