-Direct tube to the flue gas
-Material normally medium carbon steel
-OD size 2~3 inches and thickness 3.2 ~4.5 mm
Downcomer tube
-Not direct to the flue gas
-OD > 6 in
Superheater tube
- To add heat to the steam without raising the pressure of the steam
-Material High Carbon steel
-Generate superheated steam
lDistributing tube/water injection
-to distribute water into drum – below LWL
Economizer tube
-To increase temp feed water before it enters to the boiler drum and reduce flue gas temp
-after the last path of flue gas
