Used 2137 Sq Ft. U-Tube Heat Exchanger. Mfg by Energy Exchanger, Built 1988. Carbon steel Shell (SA-516) rated 300 PSI @ 650 deg F; Carbon Steel Tubes (SA-214) rated 300 PSI @ 650 deg F. Carbon Steel Heads (SA-516). Shell - 2'7.5" dia. x 19'L ; (328) Tubes - 3/4" dia. Flanged Nozzles: (2) 8", (2) 6", (2) 3/4". Type AEU. S/N: X-2968, NB# 1300.