| 摘要 |
<p>1530603 Pressure swing air separation process UNION CARBIDE CORP 29 Oct 1975 [30 Oct 1974] 44494/75 Heading B1L A pressure swing process for air separation by selective adsorption of at least nitrogen alternately in at least two crystalline zeolite beds of at least 4‹A apparent pore size and in which each bed cyclically undergoes the steps of, (a) introduction of feed air at ambient temperature of less than 90‹F at a high pressure with discharge of a gas containing at least 60% vol O 2 ; (b) release of additional oxygen by co-current depressurisation of the bed to a lower pressure, with return of part of the additional oxygen for repressurisation of another bed; (c) release of waste gas by counter current depressurisation of the bed to a lowest pressure with countercurrent purge of the bed with oxygencontaining gas from another bed; and (d) repressurisation with oxygen-containing gas from another bed; wherein the gas flows are such that the coldest gas temperature within the first bed inlet end (the first 30% of the bed) is no higher than 35‹F and the temperature difference within the first bed inlet end is at least 15‹F, is modified by heating the inlet end only of the bed by an external source sufficiently to maintain a maximum temperature of the gas flowing therethrough of at least 20‹F warmer than such gas without such heating, but less than 175‹F. Embodiments are described using two (Fig. 7 not shown), three (Fig. 6 not shown) or four (Fig. 4 not shown) adsorbent beds.</p> |
