Download pdf - Sub Critical Utility Boilers

Utility Boilers from Thermax Babcock & WilcoxUtility Boilers from Thermax Babcock & Wilcox

RadiantRadiantUtilityUtility

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UtilityUtilityBoilerBoiler


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Utility Boilers from Thermax Babcock & WilcoxUtility Boilers from Thermax Babcock & WilcoxB&W Boiler B&W Boiler TechnologyTechnology

Then…Then…

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Now…Now…


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Proprietary and Confidential The Babcock & Wilcox Company - Overview.4


»» Developed by Babcock & Wilcox, USADeveloped by Babcock & Wilcox, USA

»» First Radiant Boiler (RB) unit installed in 1936First Radiant Boiler (RB) unit installed in 1936

»» 700+ RB installations worldwide, upto 900 MW 700+ RB installations worldwide, upto 900 MW

BackgroundBackground

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»» 700+ RB installations worldwide, upto 900 MW 700+ RB installations worldwide, upto 900 MW

»» Operating pressure: subcritical rangeOperating pressure: subcritical range

»» Operating temperature: 538 Operating temperature: 538 -- 566566°°CC

»» Carolina type RB designed for pulverised coalCarolina type RB designed for pulverised coal

»» El Paso type RB designed for natural gas and/or oilEl Paso type RB designed for natural gas and/or oil


Key Technical FeaturesKey Technical Features

»» Front wall/opposed wall firing techniqueFront wall/opposed wall firing technique

»» Multiple levels of burners (1 standby)Multiple levels of burners (1 standby)

»» Interlacing of burners at different elevationsInterlacing of burners at different elevations

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»» Single drum construction; topSingle drum construction; top--supported unitsupported unit

»» Balanced draft, natural circulation designBalanced draft, natural circulation design

»» B&W mills of vertical spindle typeB&W mills of vertical spindle type

»» Coal feeders with load cell for coal flow Coal feeders with load cell for coal flow measurementmeasurement

»» CeramicCeramic--lined bends in fuel conveying pipeslined bends in fuel conveying pipes


»» Axial/centrifugal type PA & FD fansAxial/centrifugal type PA & FD fans

»» Centrifugal type ID fanCentrifugal type ID fan

»» B&W design low NOx DRBB&W design low NOx DRB--XCL burnersXCL burners

Key Technical FeaturesKey Technical Features…contd.…contd.

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»» All seamless tubes and headers for pressure partsAll seamless tubes and headers for pressure parts

»» Machine welded membrane wall furnaceMachine welded membrane wall furnace

»» Steam cooled roof tubes and second passSteam cooled roof tubes and second pass

»» Convective & radiant superheater Convective & radiant superheater

»» Regenerative trisector type/bisector type air preheaterRegenerative trisector type/bisector type air preheater


Carolina Carolina Type Type Radiant Radiant BoilerBoiler

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»» Burners on front & rearBurners on front & rear

»» B&W low NOx burnersB&W low NOx burners

»» Arranged by levelArranged by level

»»Uniform heat input Uniform heat input across furnace widthacross furnace width

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across furnace widthacross furnace width

»»Uniform gas Uniform gas temperature temperature

»»Reduced slaggingReduced slagging


Large archLarge arch

»» Prevent hot gas Prevent hot gas byby--passing passing platensplatens

»» Eliminate slag Eliminate slag initiation area at initiation area at lower leading lower leading edge of edge of

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edge of edge of secondary secondary superheatersuperheater

»» Improves Improves cleanliness and cleanliness and run time with run time with difficult coalsdifficult coals


Natural circulationNatural circulation

»» B&W drum internalsB&W drum internals

»»Wide level rangeWide level range

»»Steam separation from Steam separation from waterwater

»»Water separation from Water separation from steamsteam

»» B&W Ribbed TubesB&W Ribbed Tubes

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»»Hopper to roofHopper to roof


Natural circulationNatural circulation

»» B&W drum internalsB&W drum internals

»»Wide level rangeWide level range

»»Steam separation from waterSteam separation from water

»»Water separation from steamWater separation from steam

CycloneCycloneCycloneCycloneSteam Outlet StubSteam Outlet StubSteam Outlet StubSteam Outlet Stub

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DowncomerDowncomerDowncomerDowncomer

Feed Water Feed Water Feed Water Feed Water

PipePipePipePipe

Riser StubRiser StubRiser StubRiser Stub


Gas Tight ConstructionGas Tight Construction

»» Water cooled Water cooled membrane wall furnace membrane wall furnace enclosureenclosure

»» Steam cooled Steam cooled membrane wall membrane wall convection pass convection pass enclosureenclosure

»» All welded tight roof All welded tight roof

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»» All welded tight roof All welded tight roof constructionconstruction


Parallel back passParallel back pass

»» Reheat temperature Reheat temperature control by gas biasingcontrol by gas biasing

14Idler Bearing


Kansas City Power & LightKansas City Power & LightHawthorn, Unit 5Hawthorn, Unit 5

»» 550 MW550 MW

»» Main SteamMain Steam

»»4,000,000 lb/hr4,000,000 lb/hr

»»2600 psi, 1005F2600 psi, 1005F

»» RH SteamRH Steam

»»3,600,000 lb/hr3,600,000 lb/hr

»»547 psi, 1005 F547 psi, 1005 F

»» PRB Coal, 2001 OperationPRB Coal, 2001 Operation

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»» PRB Coal, 2001 OperationPRB Coal, 2001 Operation


Typical Subcritical Boiler and Typical Subcritical Boiler and Environmental Equipment for Environmental Equipment for Pulverized CoalPulverized Coal

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Demonstrated Benefits of B&W’s Demonstrated Benefits of B&W’s WallWall--mounted Burnersmounted Burners

»» Complete combustion near the burnerComplete combustion near the burner

»» Low carbon in ash Low carbon in ash

»» Low NOx & ultra low NOx burners feasibleLow NOx & ultra low NOx burners feasible

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»» Superior turndown ratio (without oil support)Superior turndown ratio (without oil support)

»» Flexibility of individual burner operationFlexibility of individual burner operation

»» Number of burners independent of number of mills Number of burners independent of number of mills

»» No flame impingement on furnace wallsNo flame impingement on furnace walls

»» Furnace width independent of depth (flexibility in Furnace width independent of depth (flexibility in furnace design) furnace design)


PCPC--Fired Low NOX DRBFired Low NOX DRB--XCL® BurnerXCL® Burnerwith Conical Diffuserwith Conical Diffuser

Outer ZoneAdjustable

Vane

Stationary Vane

Conical

Sliding Air Damper

Air MeasuringPitot Grid

Inner ZoneAdjustable

Vane

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Pulverized CoalandPrimary Air Inlet

ConicalDiffuser

Vane


Low NOX DRBLow NOX DRB--XCL™ Burner Combustion ZonesXCL™ Burner Combustion ZonesOuter Zone & Inner Zone Adjustable Spin VanesSliding Air

DamperAir Measuring Device

Inner secondary air zone with recirculation to base of flame

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Pulverized Coal and Primary Air Outer secondary air

zone air mixing

A High temperature, fuel rich devolatizing zone

B Formation of NOx reducing species

C NO decomposition

D Char oxidation (carbon burnout)


SALIENT FEATURES OF THE MILL SALIENT FEATURES OF THE MILL

»» Babcock & Wilcox Babcock & Wilcox technologytechnology

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»» Higher wear lifeHigher wear life

»» Lower power consumptionLower power consumption

»» Lower rejects rateLower rejects rate


»» Requires minimum Requires minimum number of replacement number of replacement of partsof parts

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»» Allows easy Allows easy maintenancemaintenance

»» Capable of grinding Capable of grinding wide variety of coalswide variety of coals


Axial FansAxial Fans

»» Axial fans for higher capacity PA and FD Axial fans for higher capacity PA and FD applicationsapplications

»» Higher efficiencyHigher efficiency

»» Variable Blade Pitch ControlVariable Blade Pitch Control

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»» Variable Blade Pitch ControlVariable Blade Pitch Control

»» Quick and responsive control systemQuick and responsive control system

»» Easier maintenanceEasier maintenance


Air PreAir Pre--HeaterHeater

»» Regenerative Type Rotary APHRegenerative Type Rotary APH

»» NonNon--contact type sealing arrangementcontact type sealing arrangement

»» Double seal arrangement to minimise air to gas Double seal arrangement to minimise air to gas

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»» Double seal arrangement to minimise air to gas Double seal arrangement to minimise air to gas ingressingress

»» Less wear and tear at the sealsLess wear and tear at the seals

»» May be triMay be tri--sector type/bisector type.sector type/bisector type.


Typical TriTypical Tri--sector Type Regenerative Air sector Type Regenerative Air PrePre--HeaterHeater

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Thank You

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Thank You