A process increases the concentration of normal paraffins in a feed stream comprising separating a naphtha feed stream into a normal paraffin rich stream and a non-normal paraffin rich stream. The non-normal paraffin rich stream is isomerized over a first isomerization catalyst to convert non-normal paraffins to normal paraffins and produce a first isomerization effluent stream. An iso-C4 stream is separated from the first isomerization effluent stream and isomerized over a second isomerization catalyst to convert iso-C4 hydrocarbons to normal C4 hydrocarbons and produce a second isomerization effluent stream. The normal paraffin rich stream, the normal paraffins in the first isomerization effluent stream and/or the second isomerization effluent stream may be fed to a steam cracker.