Three Main Flow System In Boiler Steam
Some boiler models belongs to dual-drum, longitudinal layout, and traveling grate boiler. Its traveling grate and superheater will be assembled at site, but the front and rear furnaces, convection heating surface, economizer and air preheater are assembled in the factory.
Each part will be set up together as a unit, then the furnace will be constructed, the steam-water connecting piping, flue and air duct, instruments and valves will be installed, and after that water and electricity will be connected, at last the boiler can be put into running.
In this Boiler model, the main flow system as follow :
1. Flow of the boiler steam and water system:
Soften water > Water tank > Water pump > Economizer > Steam drum > Convection tube bundle > Water drum > downcomer > Furnace lower header > Heating surface of water cooled wall > Furnace upper header > Steam drum > Main steam pipe > Superheater inlet header > Attemperator > Superheater outlet header
2. Flow of the flue gas system
Air is sent into the general air duct by the forced draft fan, and passes through the air preheater (being preheated here), the bottom air chamber, the two sides air ducts of grate, the eight air grid plates of independent air chamber, the coal layer on the traveling grate surface (fired and burnt here) step by step. Then the generated gas after combustion enters into the slag-proof tube bundle from the furnace, next passes through the superheater, the convection tube, the economizer, the airpreheater to the dust collector, finally is drawn out by the induced draft fan and dispelled to the atmosphere via the stack.
3. Flow of the ash system
The ash generated after fuel combustion rushes and streams with the flue gas. One part of the ash subsides into the combustion chamber, runs across the guiding port of the furnace radiation arc, and falls on the traveling grate; the other part of the ash collides with the slag-proof and convection tube bundles and periodically is discharged on the travelling grate through the ash hopper.
At last the ash with the combustion slag is exhausted into the hopper of slag extractor at the end of the traveling grate, and then is vented by the slag extractor.
The coal and ash leaked on the traveling grate will run with the traveling grate, be brought into the front ash box and be hollowed out here.
