S1: BO ILERS - Marine Engineering

S1:BOILERS

D.Lambert

INTRO

DUCTIO

N

CLOSEDFEEDSYSTEM

Turbines

UnderLPTurbine

2-stageCentrifugalPumps

LP

RemovalofAir&Non-condensible

Gases

AssistsDe-aeraGonProcessStartedin

AirEjector

HP

Superheater

Economiser

S1:BOILER

S–BOILEREFFICIEN

CIES

(Typical)FuelAnalysis:Carbon88%,Hydrogen10%,Sulphur1,2%&Oxygen0,4%

CombusLonofCarbon,Hydrogen&Sulphurcomponentsrepresentheatlossduetogases.

Hydrogenfromtheprocessrepresentsheatlossduetomoisture.

HeatSupplied43MJ/kg

HeatLoss(Gas)1,27MJ/kg(2,9%)

HeatLoss(Moisture)2,22MJ/kg(5,1%)

ToSteam(BoilerEfficiency)35,91MJ/kg(92%)

S1:BOILERS

SCOTCHBO

ILERSCOTCHBOILER

Scotch Boiler

•  Madeoflowcarbonsteel(UTS430to540MN/m2)

•  Furnaces are corrugated for strength,whichalsoincreases the heaLng surface area. Thickness islessthan22mmforgoodheattransfer.

•  Whenraisingsteam,caremustbetakentoensureeven heat transfer over a long period (up to 24hours). This is so as to avoid ‘straining’ the boiler,therebyminimizingthestressintheplaLng.

•  Safety valves are usually improved high lib type,fidedwith easing gear. Drain lines (no cocks) areprovided.

•  Fided with 2 gauge glasses to determine waterlevel.

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S1:BOILERS

FIRETUBEBOILERFIRETU

BEBOILER

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BEBOILER

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BEBOILER

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BEBOILER

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BEBOILER

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BEBOILER

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WATERTUBEBOILERWATERTU

BEBOILER

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WATERTUBEBOILER

Typicalparameters

Steampressure: 53barEvaporaLon: 90,000kg/hrSteamtemperature: 515degC

•  AllgeneraLngtubesarerisers,withthewaterdrumbeingfedbyexternallargeboredowncomerstoensureposiLvecirculaLon

•  About5downcomerswouldbefoundatfrontandbackoftheboiler

•  SuperheatersaresituatedinthegeneraLngsecLon,beforetheeconomisers.

ESDtypeboiler(Externalsuperheater–DType)

WATERTU

BEBOILER

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WATERTU

BEBOILER

WATERTUBEBOILERSCHEMATIC

Roof-firedOr

Side-fired

Pre-heatsCombusGonAir

SuperheatTemperature

Control

FeedwaterIn

ExhausttoFunnel

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BEBOILER

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BEBOILER

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BEBOILER

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WATERTU

BEBOILER

WATERTUBEBOILER(7/8)

WATERTU

BEBOILER

WATERTUBEBOILER(8/8)

S1:BOILERS

COCHRAN

BOILER

COCHRANBOILER

Cochran Boiler

•  Madeoflowcarbonsteel

•  Workingpressureusuallyintheregionof7bar

•  The single pass composite Cochran boiler has 2uptakes,onefortheexhaustgasandonefortheoilfiredburner

•  The furnace ispressedoutofa singleplate,and isseamless

•  The bodom of the furnace is connected to theboiler shell plaLng by a seamless ‘ogee’ ring. Thisring is pressed out of thicker plaLng than thefurnace, as the circulaLon in this region is not asgood as elsewhere in the boiler. Deposits mayaccumulate in this region due to the poorcirculaLon.

•  Thetubesareusuallyofasinuflodesigninordertoincreasetheheattransferbybafflingthegases.Thewave formaLon lies in a horizontal plane whenfided to eradicate the collecLon of dirt andmoisture.

•  Tell tale holes around the circumference allow forthe detecLon of leakages between the ‘ogee’ ringandtheboilershell.

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S1:BOILERS

PACKAGEBOILER

•  Compact,designedforUMSoperaLon

•  +/- 90% of feed water is evaporated (theremainder carrying sludge/scale to the separatorformanual/automaLcblow-down.

•  With an increase in steam demand, the pressuredrop in the separator sends a signal to the feedcontroller, which increases the feed, fuel and airsupply.

Typicalparameters

Steampressure: 10barEvaporaLon: 3,000kg/hr.Thermalefficiency: 80%Fullsteaminabout3to4minutes

PACKAGEBOILER

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PACKAGEBOILERPACKAGEBO

ILER(2/3)

PACKAGEBOILER(TUBELESS) PACKAGEBOILERPACKAGEBO

ILER(3/3)

S1:BOILERS

STEAM-TO-STEAMGENERATORSTEAM

-TO-STEAM

GENERATO

R(1/2)

STEAM-TO-STEAMGENERATORSTEAM

-TO-STEAM

GENERATO

R(2/2)

S1:BOILERS

DOUBLEEVAPORATIONBOILERDO

UBLEEVAPO

RATIONBO

ILER(1/1)

S1:BOILERS

REFRACTORIESREFRACTORYQUARL REFRACTORYCONSTRUCTION

REFRACTORYCONSTRUCTION

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REFRACTORIESREFRACTORYFAILURE REFRACTORYFAILURE

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S1:BOILERS

TUBES

MONOWALLCONSTRUCTION MONOWALLCONSTRUCTION(1/1)

S1:BOILERS

STEAMDRU

M

STEAMDRUMCONSTRUCTION(1/1)

S1:BOILERS

SUPERHEATCO

NTRO

LSUPERHEATCONTROL(DAMPERS)

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SUPERHEATCO

NTRO

LSUPERHEATCONTROL(INSTEAMDRUM)

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SUPERHEATCO

NTRO

LSUPERHEATER SUPERHEATEREXPANSION

SUPERHEATEREXPANSION

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SUPERHEATCO

NTRO

LDE-SUPERHEATING

SUPERHEATING

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S1:BOILERS

ECONOMISERS

ECONOMISERS ECONOMISERS(1/1)

QuickQuesLons…..

WhatisresponsibleforthenaturalcirculaLoneffectinwatertubeboilers?Theairbubblesthatformwhenheatedreducethedensity.

WhyislowcarbonsteelusedfortheconstrucLonofboilers?ToensureducLlityofthematerial,andthusincreasethesafetymargin.

Whyaretwogaugeglassesfidedtoanyoneboiler?Toincreasethesafetymargin,andensurethelevelcanbereadifthevesselisheeledovertooneside.

Howisthedegreeofsuperheatcontrolled?Withtheuseofanademporator(ordesuperheater)thatactstoreducethedegreeonsuperheat(air–stream,waterofsteamdrumorwiththeaidofdampers).

Whatpurposedoestheeconomiserserve?Toincreasethetemperatureofthefeedwatergoingintotheboilertoreduceimproveefficiencyandreducetheriskofthermallyshockingtheboiler.

STEAMASSIGN

MEN

TSTEAMASSIGNMENT1

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S1:BOILERS

S1: BO ILERS - Marine Engineering

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