| 摘要 |
<p>A process is described for separating off a nitrogen-rich fraction from a feed fraction containing essentially nitrogen and hydrocarbons, wherein the feed fraction is separated by rectification into a nitrogen-rich fraction and a methane-rich fraction, the methane-rich fraction, for the purpose of cold generation at a pressure as high as possible, is vaporized against the feed fraction which is to be cooled and superheated and the nitrogen-rich fraction is compressed at least occasionally and/or at least in part and is fed to the rectification as reflux stream. According to the invention at least occasionally at least a substream (16) of the compressed (C) nitrogen-rich fraction (9′) is expanded (f) after condensation (E1) thereof and, for the purpose of cold generation, is at least in part, preferably completely, vaporized (E1).</p> |
