boiler classification by, engr rehan khan salarzai

Boiler Classification With Animation

By, Engr Rehan Zeb Khan Bajaur Agency

Boiler And its Classification

Boiler, Boiler is an apparatus to produce steam. Thermal energy released by combustion of fuel is used to make steam at the desired temperature and pressure.

Engr, Rehan Zeb Khan PMAS-Arid University Rawalpindi

Types of Boilers1.Fire Tube Boiler2.Water Tube Boiler3.Packaged Boiler4.Stoker Fired Boiler5.Pulverized Fuel Boiler6.Waste Heat Boiler7.Fluidized Bed (FBC) Boiler


Boiler Classification

Fire Tube boiler

Water Tube boiler

Packaged boiler

Stoker Fired

Pulverized

Horizontal straight tube boilers

Bent tube boilers

Cyclone fired boilers


1. Fire Tube BoilerIn fire-tube boilers, combustion gases pass through the inside of the tubes with water surrounding the outside of the tubes.

Advantage of Fire Tube Boiler(i) Low cost(ii) Fluctuations of steam demand can be met easily(iii) It is compact in size. Disadvantage of Fire Tube Boiler

The disadvantages are the excessive weight-per-pound of steam generated, excessive time required to raise steam pressure because of the relatively large volume of water, and inability to respond quickly to load changes, again, due to the large water volume. Engr, Rehan Zeb Khan PMAS-Arid University Rawalpindi

2. Water Tube BoilerIn a water-tube boiler the water is inside the tubes and combustion gases pass around the outside of the tubes.


Heat in

Heat out

Water


Advantage of Water Tube Boiler (1),More efficient combustion space allowed,,

(2),In water tube boilers roof and floor tubes are sloped at 15' to ensure circulation,,

(3),Saving in space for same steaming rate,,

(4),Thin tubes are easier to bend, expand and bell mouth


Disadvantage of Water Tube Boiler

1,Lower reserve of water means a more efficient water level control is required.2,High quality feed required.3,little allowance to corrosion.


(BIB Cochran, 2003)

3. Packaged Boiler

Oil Burner

To Chimney

• Comes in complete package

• Features• High heat transfer• Faster evaporation • Good convective

heat transfer• Good combustion

efficiency• High thermal

efficiency


4. Stoke Fired Boilers

Uses both suspension and grate burning

Coal fed continuously over burning coal bed

Coal fines burn in suspension and larger coal pieces burn on grate

Good flexibility to meet changing load requirements

Preferred over other type of stokers in industrial application

5. Pulverized Fuel Boiler

• Pulverized coal powder blown with combustion air into boiler through burner nozzles

• Combustion temperature at 1300 -1700 °C

• Benefits: varying coal quality coal, quick response to load changes and high pre-heat air temperatures

Coal is pulverized to a fine powder, so that less than 2% is +300 microns, and 70-75% is below 75 microns.Coal is blown with part of the combustion air into the boiler plant through a series of burner nozzles.


6. Waste Heat Boiler

• Used when waste heat available at medium/high temp

• Auxiliary fuel burners used if steam demand is more than the waste heat can generate

• Used in heat recovery from exhaust gases from gas turbines and diesel engines


The End


boiler classification by, engr rehan khan salarzai

Engineering