Air Products and Chemicals, Inc.

Michael Henry Evans

Brian Alfred McNeil

Gregory Khosrov Arslanian

Joseph Anthony Schillinger

Coolant gas recovery and reuse from a heat exchanger is automatically interrupted when the oxygen content of the used gas exceeds a predetermined maximum concentration and is recommenced when the oxygen content falls below a predetermined minimum concentration. The mass flow of coolant gas introduced into the passageway is controlled independently of its composition and, during normal operation, the mass flow ratio of coolant gas withdrawn for recovery to coolant gas introduced into the heat exchanger is maintained constant. This ratio can be ramped up to the constant level in a predetermined manner on start up of fiber cooling and following recovery interruption. The invention provides both methods and apparatus and has particular application to Optical Fiber manufacture.

Method and apparatus for hot continuous fiber cooling with cooling gas recirculation

Nitrogen is removed from a natural gas feed stream by a cryogenic distillation process in which said feed stream is fed to a primary column of a distillation column system having a primary column and a secondary column fed from and operating at substantially the same pressure as the primary column. At least a portion of a primary column methane-rich bottoms liquid is expanded and at least partially vaporized in heat exchange with a condensing primary column nitrogen-enriched vapor. The at least partially condensed primary column nitrogen-enriched vapor is returned to the primary column to provide higher temperature reflux to the distillation column system. A secondary column methane-rich bottoms liquid is at least partially vaporized in heat exchange with a condensing nitrogen-rich overhead vapor to produce a further methane-rich product. At least a portion of the at least partially condensed nitrogen-rich overhead vapor portion is returned to the primary or secondary column to provide lower temperature reflux to the distillation column system.

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Antwerp, Belgium

Michael Henry Evans