Dear Shiva

ISO Recycle is not a well defined refining term two possible definitions com quickly to mind but I am sure there are others.  The first is Naphtha Isomerization unit recycle. The purpose of a naphtha Isom unit is to convert N-Paraffins in Naphtha into Iso-Paraffins in order to improve Octane the feed is typically primarily C5/C6 paraffins but there may be some C4s and C7s.  There may be some benzene in the feed the will be saturated to cyclohexane but the feed and product is typically >99% paraffin.  Since the advent of Benzene in the feed which will become cyclohexane in the product.  Unit in this mode of operation usually don't recycle but some probably do.

The term Iso Recycle could also refer to Isocracker bottoms recycle.  Isocracking is a trademark name that Chevron and UOP use for their Hydrocracking units.  Feed to a hydrocracker can be extremely aromatic material like delayed coker of FCCU product or extremely paraffinic material like vacuum gas oil for lubes.  The bottoms recycle sometimes referred to as Isocracking recycle or Isorecycle could vary from 20% Paraffins up to 99%+ paraffin.

I hope this answers your question,  If it doesn't please clarify the question and I will try again.

Best Regards

Rick

what do u mean how much paraffin we have in it?! its a source to produce paraffin wax