{HEAD ~ An inlet} 26 is provided for {TAIL ~ the reactant header} which introduces reactant thereto which in turn flows within the tubes of the tube bundle 12 
is provided for
{ HEAD ~ An inlet } 26 is provided for { TAIL ~ the reactant header } which introduces reactant thereto which in turn flows within the tubes of the tube bundle 12
HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH