Classification Types of Boilers Rajan Bhandari Singapore Maritime

Classification & Types of Boilers Rajan Bhandari Singapore Maritime Academy 1 6/6/2021

Introduction l l 2 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. 6/6/2021

Overview This is a introductory lecture and explains l the use of steam and l application of various types of boilers for use on a motor vessel. 3 6/6/2021

Vocabulary l l l 4 Smoke tube, Fire tube, Tank Type, Drum Type Carnot efficiency 6/6/2021

Use of Steam l l l l 5 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 6/6/2021

Use of Steam l l l l 6 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 6/6/2021

Types of boilers l l l 7 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. 6/6/2021

Smoke tube & Water tube boilers Fire tube concept Shell with fire tubes inside Tank type boiler Water tube concept Drum with fire tubes 8 6/6/2021

Tank type & Drum type boilers Fire tube concept Shell with fire tubes inside Tank type boiler Water tube concept Drum with fire tubes 9 6/6/2021

Principle of heat transfer in boilers l l l 10 Radiation Conduction Convection 6/6/2021

Limiting the stress l 11 Longitudinal stress = 6/6/2021 Pressure x diameter 4 x thickness of wall

Limiting the stress l 12 Circumferential stress = Pressure x diameter 2 x thickness of wall 6/6/2021

Maximum working pressure l l 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 13 Water tube concept Drum with fire tubes 6/6/2021

Compensating pads 14 6/6/2021

Position of manholes 15 6/6/2021

Compensating ring 16 6/6/2021

Supporting flat surface 17 6/6/2021

Supporting flat surface 18 6/6/2021

Sunrod CHS 19 6/6/2021

MIURA Z - Boiler 20 6/6/2021

Water tube Boiler 21 6/6/2021

Water and steam flow diagram 22 l Blue: the downcomers lead the water from the steam drum to the water drum and the waterwalls headers. l Red and blue: the evaporation tubes and the water walls lead the water and steam emulsion back to the steam drum. l Red: the steam passes through the superheater before it leaves the boiler for the consumers. 6/6/2021

Boiler with integral super heater Keep superheater vent open and maintain flow to prevent overheating 23 6/6/2021

Carnot efficiency Carnot's Eff iciency % = (T 1 ‑ T 2 ) x 100 (T 1) l Turbo alternator l T 2 at condenser l T 1 T 2 24 6/6/2021

Efficient heat exchange l l 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 25 6/6/2021 T 2

Summary l l 26 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. 6/6/2021

Where to Get More Information l l l 27 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) 6/6/2021