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