Air Products and Chemicals, Inc.

David Edward Guro

David M Nicholas

Ravi Kumar

William T Kleinberg

Mark Robert Pillarella

Joseph P Bushinsky

Gary S Roth

A method for operating a pressure swing adsorption process at turndown conditions by adding selected steps to the normal design operation of the process. The selected steps include the extension of a make product/no feed step and the addition of idle steps at specific points in the process cycle during depressurization and repressurization. The average volumetric flow ratio of the pressurized feed gas to the final product gas during design operation and during turndown operation may be essentially equal. The average oxygen concentration in the final product gas during design operation and during turndown operation also may be essentially equal.

Pressure swing adsorption process operation at turndown conditions

The present invention is an integrated process for the adsorptive recovery of a high purity carbon monoxide product from a gas mixture containing hydrogen, carbon monoxide, carbon dioxide, methane, and nitrogen, with the potential additional recovery of a hydrogen-rich stream and the recycle of the resulting gas mixture to a reformation reaction to produce the gas mixture with a more favorable carbon monoxide and hydrogen product slate. Separate carbon dioxide recovery can be performed. Hydrogen recovery can be either by adsorptive or by membrane technology. The process achieves high recoveries at reduced capital cost and at reduced product cost.

Integrated processes for the production of carbon monoxide

Crude ammonia synthesis gas is obtained by primary steam reforming of a hydrocarbon gas mixture rich in methane, such as natural gas, followed by secondary reforming of the primary reformate with added air and shift conversion of the contained CO to CO.sub.2. The shift conversion product is first freed of contained CO.sub.2 by selective absorption in a novel PSA unit having an integrated B section for removal of remaining impurities such as carbon monoxide and methane, thereby providing as product a gas stream comprised of hydrogen and nitrogen in approximate 3:1 molar ratio accompanied by a small amount or argon derived from the air stream used in the secondary reforming step. Alternative embodiments are disclosed for removal of CO from the gas stream, before its entry into the NH.sub.3 conversion operation; any residual CO that might have slipped thorugh the absorbent bed of the B section is converted to CH.sub.4.

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Coopersburg, PA, United States of America

David Edward Guro