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