US 5,170,630 A · Process and apparatus for producing nitrogen of ultra-high purity

Abstract

The present invention provides an apparatus and method for producing ultra-high purity nitrogen. In accordance with the method and apparatus, air is rectified to produce a tower overhead comprising high purity nitrogen rich in light elements, such as neon, helium and hydrogen. The tower overhead is then partially condensed within a condenser and separated into liquid and vapor phases within a phase separator. The liquid phase is lean in the light elements and the vapor phase is rich in the light elements. The liquid phase is removed from the bottom of the phase separator and is introduced into the column as reflux. As the reflux drops from tray to tray it is stripped of the light elements. A product stream containing ultra-high purity nitrogen is withdrawn as a liquid from the column after suitable stripping of the reflux. The product stream can be further purified by stripping the product stream within a stripper column.

Claims21

Dependent claims

A process of producing ultra-high purity nitrogen comprising:

rectifying air within a rectification column by a low temperature rectification process to produce a tower overhead containing a high purity nitrogen vapor rich in light elements;
partially condensing a stream of the tower overhead so that the stream contains a liquid phase lean in the light elements and a gaseous phase rich in the light elements;
separating the gaseous phase from the stream of the tower overhead;
returning the stream of the tower overhead, after separation of the gaseous phase therefrom, to the rectification column as reflux and stripping the light elements from the reflux within the rectification column to produce the ultra-high purity nitrogen as liquid;
and
extracting a product stream from the rectification column composed of ultra-high purity nitrogen liquid.

3 more elements

An apparatus for producing ultra high purity nitrogen comprising:

low temperature rectification means having a rectification column for rectifying air within the rectification column so that nitrogen and light elements concentrate as tower overhead in the form of a high purity nitrogen as vapor rich in the light elements;
condensing means connected to the top of the rectification column for partially condensing a stream of the tower overhead so that the stream contains a gaseous phase rich in the light elements and a liquid phase lean in the light elements;
phase separation means receiving the stream of the tower overhead from the condensing means for separating the gaseous phase from the stream of the tower overhead;
the phase separation means connected to the top of the rectification column so that the stream of the tower overhead, after separation of the gaseous phase therefrom, returns to the top of the rectification column as reflux;
the column sized such that the reflux is stripped of the light element to form the ultra high purity nitrogen as liquid below the top of the column;
and
delivery means for extracting a product stream composed of ultra-high purity nitrogen liquid from the rectification column and for delivering the ultra-high purity nitrogen from the apparatus.

4 more elements

Dependencies are inferred from the claim text.

Process and apparatus for producing nitrogen of ultra-high purity

Life of this patent

Process and apparatus for producing nitrogen of ultra-high purity

Life of this patent

Abstract

Claims21