1. Classification & Types of Boilers
Rajan Bhandari
Singapore Maritime Academy
5/9/2019

2. Introduction Know the need for steam on a motor vessel.
Know the principles involved in heat transfer and in generating steam in a boiler.
Know the various ways the boilers can be classified.
Know the basic constructional features of some of the popular boilers used.
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3. Overview This is a introductory lecture and explains
the use of steam and
application of various types of boilers for use on a motor vessel.
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4. Vocabulary Smoke tube, Fire tube, Tank Type, Drum Type
Carnot efficiency
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5. Use of Steam
Heating duties: ME Fuel oil heater, Purifier heater, Oil tank heating, Cargo heating, Air conditioning & heating plant, Calorifier, Galley supply, sea‑chests, tracer lines for pipeline heating etc.
Run Turbine Generators
Run Cargo pump turbines in Tankers
Drive steam driven deck machinery like winches etc.
Operate bilge, stripping and other steam driven pumps
Drive boiler feed pump turbines
Evaporator/Fresh water generator heating media
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6. Use of Steam Tank washing in tanker ships and general cleaning
For boiler Soot blowing and for the steam atomised burners
Fire fighting as used in steam smothering system
Main engine Jacket F.W. preheater and Lub oil sump and drain tanks
Use in the waste oil, incinerator, slop tanks
Use as a steam ejector media for ejector pumps and
vacuum deviceswater generator heating media
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7. Types of boilers Main Boiler- Propulsion of the vessel
Auxiliary Boiler-Heating of heavy fuel oil using a steam heater, necessary for propulsion would qualify the supplying boiler to be referred to as an auxiliary boiler.
Tank Boiler-A boiler with large water carrying capacity where the shell is being used as the pressure vessel. Most low pressure auxiliary boilers will come into this category.
Exhaust Gas Boiler- Boiler operated by hot gas from engine or other exhaust gas sources.
Drum Type Boiler-Water tube boilers employing steam and water drums. They are also known as bent tube type boilers.
Package Boiler -Fully automatic, low capacity boilers packaged inside a box type casing, capable of quick steam production and flexible in being positioned anywhere; could be coil type or fire tube type.
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8. Smoke tube & Water tube boilers
Fire tube concept
Shell with fire tubes inside
Tank type boiler
Water tube concept
Drum with fire tubes
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9. Tank type & Drum type boilers
Fire tube concept
Shell with fire tubes inside
Tank type boiler
Water tube concept
Drum with fire tubes
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10. Principle of heat transfer in boilers
Radiation
Conduction
Convection
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11. Limiting the stress Longitudinal stress = Pressure x diameter
4 x thickness of wall
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12. Limiting the stress Circumferential stress = Pressure x diameter
2 x thickness of wall
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13. Maximum working pressure
Max working press. = Max stress x 2 x wall thickness
diameter
Therefore Tank type boiler max press limited to 17.5 bar
Fire tube concept
Shell with fire tubes inside
Tank type boiler
Water tube concept
Drum with fire tubes
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14. Compensating pads
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15. Position of manholes
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16. Compensating ring
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17. Supporting flat surface
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18. Supporting flat surface
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19. Sunrod CHS
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20. MIURA Z - Boiler
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21. Water tube Boiler
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22. Water and steam flow diagram
Blue: the downcomers lead the water from the steam drum to the water drum and the waterwalls headers.
Red and blue: the evaporation tubes and the water walls lead the water and steam emulsion back to the steam drum.
Red: the steam passes through the superheater before it leaves the boiler for the consumers.
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23. Boiler with integral super heater
Keep superheater vent open and maintain flow to prevent overheating
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24. Carnot efficiency Carnot's Eff iciency % = (T1 ‑ T2 ) x 100 (T1)
Turbo alternator
T2 at condenser T1 T2
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25. Efficient heat exchange
Thickness of the tube material reduces its conductivity but it is an important factor in limiting stresses in the material
Heat conducted =
Difference in temp x area x time thickness of material T1 T2
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26. Summary Need for steam on a motor vessel.
Principles involved in heat transfer and in generating steam in a boiler.
Various ways the boilers can be classified.
Basic constructional features of some of the popular boilers used.
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27. Where to Get More Information
Morton, Thomas D, Steam Engineering Knowledge for Marine Engineers (1994), Thomas Reed Publications
Flanagan, G T H, Marine Boilers Question & Answers (1995)
Operation Manuals, Aalborg Boilers
Operation Manuals, Miura Boilers
Milton, J H and Leach, Roy M, Marine Steam Boilers (1995)
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