Boiler General Arrangement

ECONOMIZER   Purpose: Preheat the boiler feed water and recover some of the heat from the flue gases.  Location: Rear gas pass below the rear  horizontal SH.  Staggered arrangement.  Continuous finned tube.

ECONOMIZER   Tube size: OD 44.5 mm X 4.5 mm (thick). Material ± SA 210 Gr A1.  Probable failure causes. WJF Erosion

DRUM  FUNCTION: To separate steam and water from the mixture generated from water walls. Reduce the dissolved solid contents into acceptable limits.  Size: ID ± 1676 mm; Thickness ± 133 mm Length ± 15700 mm; hemisphere ± 940 mm Material SA 299

DRUM  Steam drum internals: Feed pipe. Separating chamber. Turbo separators. Screen dryers Chemical dosing. Blow down.

Welded Wall Construction  Water cooled furnace. Combustion and heat transfer takes place. Construction: Furnace walls Membrane type. Radiant roof is of pegfin welded construction. Rear pass roof, and rear, front and side steam cooled wall are of fin welded construction.

WATER WALL  Bottom construction: Depends on fuel and ash condition. Mostly open hopper type, often referred as dry  bottom. Leakage of air between furnace and hopper is prevented by either a water  impounded or a mechanical seal expansion  joints.

WATER WALL  Corner/tangential fired.  Tube Dia -63.5 mm Thickness ± 5.2 mm Material ± SA 210 Gr A1.  Probable failure causes. Blistering Erosion Corrosion AWF/WJF.

SUPERHEATERS  Composed of four basic stages: Pendant section, Platen section, Rear  horizontal section, and the steam cooled wall and roof sections. Location: Platen Section is located just above the furnace in front of the furnace arch. Heat absorbs mainly by radiation.

SUPERHEATERS  Pendant section is located behind the screen tubes. Predominant mode of HT is convection.  LTSH is located in the rear vertical gas pass above economizer. This is the primary SH of the convective, counter flow type.  SCW sections form the side, front and rear  walls and roof of the vertical gas flow path.

REHEATER   Reheater is composed of two sections namely front pendant and rear pendant vertical spaced section.  Location: Rear pendant is located above the furnace arch  between water cooled screen and rear water wall hangers. Front pendant is located between water wall hangers and platen section.