{HEAD ~ A reactant header} 18 is provided at the inlet side 14 of {TAIL ~ the tube bundle} and a product header 20 is provided at the outlet side 16 of the tube bundle 
{ HEAD ~ A reactant header } 18 is provided at the inlet side 14 of { TAIL ~ the tube bundle } and a product header 20 is provided at the outlet side 16 of the tube bundle
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH