Patent ID: 7964762

Claim:
A process for the selective production of olefins from light hydrocarbons comprising: fractionating a butane fraction in a de-isobutanizer to obtain an enriched iso-butane fraction and an enriched normal-butane fraction; cracking the enriched normal-butane fraction and optionally a second fraction selected from an ethane fraction, a propane fraction and combinations thereof in a non-catalytic cracking zone to produce an olefin rich stream; treating the olefin rich stream in a separating section, wherein the treating comprises: removing hydrogen and methane from the olefin rich stream; recovering a first ethylene stream, a first propylene stream, a propane stream, a first C 4 stream and an ethane stream; recycling the ethane stream and optionally the propane stream to the non-catalytic cracking zone; removing heavies from the olefin rich stream; selectively hydrogenating dienes and alkynes in the first C 4 stream into their corresponding olefins to form a hydrogenated C 4 stream; reacting by metathesis in a metathesis section the hydrogenated C 4 stream and at least a portion of the first ethylene stream to form an effluent comprising propylene; and treating the effluent to recover a second ethylene stream, a second propylene stream, a second C 4 stream and a heavies stream.