{HEAD ~ A process} for {TAIL ~ demetalation}, desulfurization and dewaxing of residual oil has been discovered using a two stage process 
for
{ HEAD ~ A process } for { TAIL ~ demetalation } , desulfurization and dewaxing of residual oil has been discovered using a two stage process
HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH