Praxair Technology, Inc.

Edward Paul Eardley

Minish Mahendra Shah

Bart Antonie Van Hassel

Vijayaraghavan Srinivasan

Eric Hunter Shreiber

A method of separating oxygen using a ceramic membrane unit having one or more ceramic membranes, preferably formed of a mixed conducting ceramic, for instance, a perovskite, capable of conducting both oxygen ions and electrons. Oxygen is separated within the ceramic membrane unit under impetus of compressing an incoming oxygen containing feed. The compressor used in the compression is powered by the work of expansion produced by expanding a process stream composed of at least a portion of the retentate produced in the ceramic membrane unit. Prior to expansion, the process stream is cooled to allow the use of less expensive materials in expanders used in the expansion. As a result, expansion of the process stream alone is insufficient to meet the power requirements involved in the compression. Interstage expansion with reheating is used to make up for the power deficit.

Oxygen separation method using a ceramic membrane unit

A method for improving the capability of a body to withstand stress during rotation of the body by inducing at a selected location in the body a residual compressive stress which opposes the steady tensile stress produced by rotation. The method comprises rotating the body at a succession of increasing peak speeds in excess of the design speed to induce tolerable yielding and residual compressive stress at each location experiencing higher steady tensile stress than the selected location. The succession proceeds from the location experiencing the highest steady tensile stress above that at the selected location to the location experiencing the lowest steady tensile stress above that at the selected location. Then the body is rotated to a still higher peak speed to induce tolerable yielding and residual compressive stress at the selected location.

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Lockport, NY, United States of America

Edward Paul Eardley