Praxair Technology, Inc.

James Brian Mize

Dante Patrick Bonaquist

John Henri Royal

Harry Cheung

James R Dray

Mark J Roberts

Paul Louis Just

A pressure swing adsorber (PSA) air prepurifier includes at least a first adsorber and a second adsorber and a controller for controlling air feed to the first adsorber and the second adsorber. The invention is a 'realtime' method for controlling cycle times for each adsorber and includes the following steps. During a determined time period, flow is measured to an adsorber that is coupled to an air inlet. An actual totalized flow to the on-line adsorber is accumulated, based upon the measured flow values. During this time, air feed conditions (e.g., temperature, pressure, relative humidity) are monitored and periodically, a maximum totalized flow to the adsorber is calculated, determined, at least in part, based upon the monitored air feed conditions. Periodically, the actual totalized flow value is compared to a current calculated maximum totalized flow value and upon a predetermined relationship therebetween being reached, the on-line adsorber is decoupled from the air inlet and another adsorber is coupled thereto. The method for controlling cycle times for each adsorber also will take into consideration: variations in load demand, purge to feed ratio and upsets which occur on switching of adsorber beds.

Method for operation of an air prepurifier which takes into account

A single column lower pressure cryogenic rectification system wherein nitrogen top vapor is condensed against column bottoms, elevated in pressure, and vaporized against elevated pressure fluid to achieve simultaneously high purity and high pressure nitrogen gas product.

Single column cryogenic rectification system for producing nitrogen gas

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Williamsville, NY, United States of America

James Brian Mize