At this point, gas flow is initiated and {HEAD ~ the reactant material} is introduced into {TAIL ~ the inlet} of the reactor as shown by arrow 154 
At this point , gas flow is initiated and { HEAD ~ the reactant material } is introduced into { TAIL ~ the inlet } of the reactor as shown by arrow 154
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH