Patent ID: 11136278

Abstract:
Processes and systems for the conversion of propylene to ethylene may include introducing a propylene feed stream to a C3 metathesis reactor, converting the propylene to ethylene and 2-butene. The metathesis reactor effluent may be recovered and separated in a fractionation system to recover an ethylene product, a C3 fraction, a C4 fraction, and a C5+ fraction. All or a portion of the C3 fraction may be fed to the C3 metathesis reactor to produce additional ethylene. The C4 fraction may be converted in a C4 isomerization/metathesis reaction zone by: (i) isomerization of 2-butenes to 1-butene, (ii) metathesis of the 1-butene and 2-butene to produce propylene and 2-pentene, and/or (iii) autometathesis of the 1-butene to produce ethylene and 3-hexene. An effluent from the C4 isomerization/metathesis reaction zone may then be recovered and fed from the C4 isomerization/metathesis reaction zone to the fractionation system.