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