Technology Unit

Low Temperature Section

The C₂^- fraction is cooled in several stages until all ethylene, ethane, and methane is condensed. The remaining gas consists of 81 mol % hydrogen.

Gas stream:

•  H₂ fraction (81 mol% H2) fed to PSA
• CH₄ fraction (96 mol% CH4), mixed as a fuel gas

Liquid stream fed to Demethanizer.

C₁/C₂ Separation

Operating pressure: 31 barg.
Methane, hydrogen and carbon monoxide are recovered overhead.
Bottom C₂ fraction is fed to C₂ Splitter.
Methane recycle is expanded to 7 barg corresponding to a temperature of -129°C for C₂ recovery.

Reference

Source: Y.A. Sastry & Uday Krishna Dy, DUAL FEED CRACKER UNIT & ASSOCIATED UNIT, ONGC Petro additions Limited (OPaL), Uploaded on 28^th Jan 2018 on SCRIBD.