US 4,732,596 AGranted

Gas separation process

AssigneeAir Products and Chemicals, Inc.

InventorsDavid M. Nicholas, Jeffrey A. Hopkins, Thomas M. Roden, Joseph P. Bushinsky

Life of this patent

Estimating the term…

Loading patent…

Abstract

Hydrogen and carbon monoxide are each separately recovered in high yield from a multicomponent gas stream containing these compounds together with carbon dioxide and a zero to minor amount of one or more gaseous components from the group consisting of nitrogen, methane, water vapor and C.sub.2 -C.sub.6 hydrocarbons, by a process wherein the multicomponent gas stream, such as that obtained by steam methane reforming, is initially treated in a pressure swing adsorption unit to remove water and CO.sub.2, and the obtained effluent freed of CO.sub.2 and water is then further subjected to (1) cryogenic fractionation to condense CO and to (2) hydrogen purification by selective adsorption (in either order) to recover high purity carbon monoxide and essentially pure hydrogen. The CO.sub.2 -laden adsorbent is regenerated by purging with a H.sub.2 O and CO.sub.2 -free waste gas stream from the hydrogen purification adsorbent bed or from the cryogenic fractionation or from both of these.

Claims22

Dependent claims

The method for production of high purity hydrogen and high purity carbon monoxide from a mixed gas stream comprising these components together with carbon dioxide and a zero to a minor amount of one or more other gaseous contaminants which method comprises the steps of:

(a) passing said mixed gas stream into and through a first bed of solid adsorbent capable of selectively adsorbing carbon dioxide and water while discharging from said bed a dry CO.sub.2 -freed effluent;
(b) introducing said dry CO.sub.2 -freed effluent into a cryogenic environment for cooling the same therein under conditions effective for condensation of at least the major part of the carbon monoxide present in said dry CO.sub.2 -freed effluent;
(c) withdrawing from said cryogenic environment carbon monoxide of high purity;
(d) separately withdrawing from said cryogenic environment an uncondensed first gas stream product comprised of crude hydrogen and subjecting said first gas stream product to selective adsorption of non-hydrogen components therefrom in a second bed of solid absorbent, while recovering from said second bed the non-sorbed fraction as a product stream of essentially pure hydrogen;
(e) purging said second solid adsorbent bed to desorb non-hydrogen components sorbed therein in step (d), and withdrawing from said bed a gas stream comprising the desorbed non-hydrogen components.

2 more elements

The method for production of hydrogen and carbon monoxide, each in essentially pure form, from a mixed gas stream obtained by steam hydrocarbon reforming of a methane-rich charge, said mixed gas stream containing in addition to hydrogen and carbon monoxide together with carbon dioxide as a major component a zero to minor amount of one or more gaseous components from the group consisting of nitrogen, methane, water vapor and C.sub.2 to C.sub.6 hydrocarbons, which method comprises the steps of initially removing carbon dioxide and water from said mixed gas stream by adsorption in a first bed of solid adsorbent selective in retention of carbon dioxide and water and further treating the obtained carbon dioxide/water-freed effluent from said first adsorbent bed by (1) cryogenic fractionation and (2) further selective adsorption, in either order, under conditions effecting removal from said carbon dioxide/water-freed effluent of contained minor components, thereby recovering the hydrogen and carbon monoxide, each in essentially pure form.

Dependencies are inferred from the claim text.