Air separation
AssigneeThe BOC Group, Inc.
InventorPaul Higginbotham
Life of this patent
Estimating the term…
Abstract
Air is separated in a double rectification column comprising a higher pressure rectification column, a lower pressure rectification column, and a condenser-reboiler placing the column in indirect heat exchange relationship with the column. A stream of pressurized liquid, comprising oxygen and nitrogen, typically taken from the bottom of the higher pressure rectification column, is expanded through a valve and is typically partially vaporized in a vaporizer-condenser which is separate from a second vaporizer-condenser in which argon is condensed. The vaporized liquid is expanded with the performance of external work in an expansion turbine and is introduced into the lower pressure rectification column. An oxygen product is withdrawn from the column through an outlet.
Claims15
A method of separating air in a double rectification column comprising a higher pressure rectification column, a lower pressure rectification column, and a condenser-reboiler placing the higher pressure rectification column in heat exchange relationship with the lower pressure rectification column, comprising:
- introducing at least one stream of air is introduced into the double rectification column;
- reducing pressure of a stream of pressurized liquid comprising oxygen and nitrogen and at least partially partially vaporizing said stream in a vaporizer-condenser separate from any condenser in which argon-rich vapor containing at least 90 mole percent of argon is condensed;
- expanding with the performance of external work a vapor stream produced from vaporization of said stream of pressurized liquid and introducing said vapor stream into the lower pressure rectification column;
- and
- withdrawing an oxygen product is withdrawn from the lower pressure rectification column.
An apparatus for separating air, comprising:
- a double rectification column comprising a higher pressure rectification column, a lower pressure rectification column, and a condenser-reboiler placing the higher pressure rectification column in indirect heat exchange relationship with the lower pressure rectification column;
- at least one inlet to the double rectification column for at least one stream of air to be separated;
- a vaporizer-condenser having vaporizing passages in communication via expansion partially or totally vaporized, the vaporizer-condenser being separate from any condenser in means with a source of pressurized liquid comprising oxygen and nitrogen to be which argon-rich vapor containing at least 90 mole percent of argon is condensable and being operable to effect the partial or total vaporization;
- an expansion turbine having a turbine inlet communicating with a vapor outlet for vapor from the vaporizer-condenser and a turbine outlet communicating with the lower pressure rectification column;
- and
- a lower pressure rectification column outlet from the lower pressure rectification column for an oxygen product.
Dependencies are inferred from the claim text.