{TAIL ~ A co processing} combining a first selective catalytic bed consisting of only one metal element selected from group VIB metals and of {HEAD ~ at least one conventional hydrotreating bimetallic catalytic bed} 
{ TAIL ~ A co processing } combining a first selective catalytic bed consisting of only one metal element selected from group VIB metals and of { HEAD ~ at least one conventional hydrotreating bimetallic catalytic bed }
TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD