THERMAL ENGINEERING BOILERS

1. THERMAL ENGINEERINGBOILERS Presented by DR. P. CHANDRA RAO M.Tech, Assistant Professor DEPARTMENT OF MECHANICAL ENGINEERING VISAKHA INSTITUTE OF ENGINEERING & TECHNOLOGY

2. B O I L E R

3. WHAT ISA ?

4. A portable boiler(preserved,Poland) A stationary boiler(UnitedStates)

5. The pressure vessel in a boiler is usually madeof steel (or alloy steel), or historically of wrought iron. Stainless steel is virtually prohibited (by the ASME Boiler Code) for use in wetted parts of modern boilers, but is used often in super heater sections that will not be exposed to liquid boiler water.

6. In live steam models, copper or brass is often used because it is more easily fabricated in smaller sizeboilers. Cast iron may be used for the heating vessel of domestic waterheaters.

7. The source of heat for a boiler is combustionof any of several fuels, such as wood, coal, oil, or naturalgas. Electric steam boilers use resistance- or immersion- type heatingelements. Nuclear fission is also used as a heat source for generatingsteam. Heat recovery steam generators (HRSGs) use the heat rejected from other processes such as gas turbines.

8. Boilers can be classified into the followingconfigurations: "Potboiler"or"Haycockboiler":aprimitive"kettle" where a fire heats a partially-filled water container from below. 18th century Haycock boilers generally produced and stored large volumes of very low-pressure steam, often hardly above that of the atmosphere. These could burn wood or most often, coal. Efficiency was verylow.

9. A fire-tube boiler is a type of boiler in which hot gases from a fire pass through one or more tubes running through a sealed container of water. The heat energy from the gases passes through the sides of the tubes by thermal conduction, heating the water and ultimately creatingsteam.

10. Diagram of a fire-tubeboiler Sectioned fire-tube boiler from a DRB Class50 locomotive.

11. A water tube boiler is a type of boiler in which water circulates in tubes heated externally by the fire. Water tube boilers are used for high-pressure boilers. Fuel is burned inside the furnace, creating hot gas which heats water in the steam- generatingtubes.

12. Schematic diagram of a marine-type water tubeboiler.

13. Diagram of a water-tube boiler.

14. A flash boiler is a type of water-tube boiler, whose tubes are strong and close together with water pumped through the tubes. The tubes are kept very hot so the water feed is quickly flashed into steam and superheated. They have theseadvantages: Less weight andbulk. Less time to raise steam fromcold. A flash boiler is much easier than an ordinary boiler to overheat, as there is no large reservoir of water to keep the tubes from high temperature if the water flow is interrupted orinadequate.

15. Sometimes the two above types have been combined in the following manner: the firebox contains an assembly of water tubes, called thermic syphons. The gases then pass through a conventional fire tube boiler. Water-tube fireboxes were installed in many Hungarian locomotives, but have met with little success in othercountries.

16. Boiler for steamlocomotive.

17. In a cast iron sectional boiler, sometimes called a "pork chop boiler" the water is contained inside cast iron sections. These sections are assembled on site to create the finishedboiler.