PFI/PFT Boilers: Rugged, Cost-Effective and

Dependable Under Fire

Since 1867, The Babcock &

Wilcox Company (B&W) has

been designing, manufacturing,

installing and commissioning

the world’s most reliable and

efficient steam-generating

systems and environmental

equipment. B&W also services,

repairs, modifies, upgrades

and replaces existing systems

and associated equipment,

regardless of the original

manufacturer. With boiler

installations operating in more

than 85 countries, B&W has

the experience and flexibility

to meet the ever-changing

needs of both the industrial

and utility markets. B&W is

recognized globally for its

unmatched responsiveness

to customers’ needs.

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BURNERSSUPERHEATER

SCREEN TUBESBOILER BANK

STEAM DRUM

FURNACE

LOWER DRUM

B&W PFI Boiler

B&W PFT Boiler

3

GAS OUTLET

SCREEN TUBES

LOWER DRUM

STEAM DRUM

SUPER-HEATER

INTEGRAL AIR PLENUM

BURNERS

STEAM COILAIR HEATER

AIRHEATER

GASOUTLET

FORCED-DRAFTFAN

FURNACE

Proven Design for Dependable Steam Production

Reliable performancein a wide variety ofindustries

B&W’s PFI (Power forIndustry) and PFT (Power for Turbine) integral furnaceboilers continue our traditionof excellence with over 275 units totaling more than78,000,000 lb/hr of steamcapacity worldwide. Ourestablished reputation forreliability and proven performance is continuallyenhanced by incorporatingcustomer feedback in

conjunction with the latesttechnological advancementsin our design. Many 1950vintage PFI/PFT boilers arestill in service today. Theconservative furnace size and burner spacing of thePFI/PFT design has provenitself to be a reliable work-horse across a wide range of heating, process andpower markets such as:• Petroleum and chemical

refineries• Pulp and paper mills• Steel mills• Manufacturing and

processing facilities

PFI PFT

Steam Flow 100,000 to 700,000 lb/h 350,000 to 800,000 lb/h(45 to 317 tm) (159 to 363 tm)

Steam Pressure Up to 1150 psig (79.3 bar) Up to 1800 psig (124.1 bar)

Steam Temperature Up to 960° F (516 C) Up to 1000° F (538 C)

Approx. Superheater Steam40 to 100% (Natural Gas) / 60 to 100% (Oil)

Temperature Control Range

Standard Sizes Available 11 37

Furnace Tube Size / Spacing 2.5 in. OD (6.35 cm) 3.0 in. OD (7.62 cm)on 3.0 in. (7.62 cm) centers on 3.75 in. (9.53 cm) centers

Superheater Tube Side Spacing 6 in. (15.24 cm) 4.5 in. (11.43 cm)

Generating Bank Gas Flow Horizontal Vertical

Fuels Natural Gas, Refinery Gas, Oil, CO, BFG, COG,Various Combustible Byproduct Gases and Liquids

Waterside Design Natural Circulation

Type of Support Bottom Support

Setting Design Pressurized Furnace

Type of Superheater Fully Drainable

Installation Indoor – Outdoor

• Utility power generationplants

• Municipalities• Heating for corporate and

institutional buildings

System componentscomplement operation

Specifically designed tocomplement each other inoperation, all major compo-nents in the PFI/PFT boilersystem can be supplied byB&W depending on yourneeds:• Boiler • Instruments and controls

• Burners, staging ports andburner management system

• Valves• Fans• Motors• Sootblowers• Flues, ducts, dampers

and expansion joints• Platforms and steel• Additional options

(feedwater pumps, fuelpump and heating set,deaerators, chemical feed systems, economizers,air heaters, environmentalequipment, steel stacks)

Pre-engineered B&W PFI/PFT boilers are available in a wide range of sizes and operating conditions:

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Designed and Built From Experience

Features and Benefits: Furnace

Welded membrane wall construction provides the gas-tight setting absolutely necessary for all PFI/PFT boilers. This construction minimizes outages caused by gas leaks. B&W’s membrane wall panels use large diameter tubes and small membrane spacing. This provides a larger volume of water in our furnace walls which results in the best combination of heat transfer efficiency, faster load response and maintenance accessibility.

3-3/4 in.3 in. O.D.Tubes

3/4 in.

3 in.2-1/2 in. O.D.Tubes

1/2 in.

With the advent of the PFIboiler in 1958, B&W’s engineers were the first torecognize that if boilerscould be designed withoutconsideration for solid fuels,they could incorporate manycost-saving features withoutsacrificing quality anddependability. Accordingly,B&W incorporated manyinnovations which had neverbefore been integrated inindustrial boilers. Theseincluded membrane wall setting, maximum shopassembly of components,fully drainable superheaters,minimal use of refractory,complete bottom support and integral air plenums.

In the late 1960s, the B&WPFT was developed in

response to the need for arugged and versatile boilerwhich would provide high-pressure, high-temperaturesteam, yet would fire practi-cally any liquid or gaseousfuel. By pre-engineering allcomponents which combinefor the various sizes andoperating conditionsrequired, B&W design engineers provided substan-tial savings in installed cost, as well as a significantdecrease in the time betweenthe placing of an order for a PFI/PFT and its initialoperation.

B&W’s PFI/PFT boilersoperate on positive furnacepressure from a singleforced draft fan, eliminatingthe need for an induced

B&W maximizes shop assembly of componentsto save time and money.

Furnace membrane walls; front, side, roof and floor

PFI PFT

Seal at furnace corner

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draft fan, motor and auxiliaries, along with the associated operating andmaintenance costs.

Without question, thePFI/PFT boiler design drivesmaintenance to a minimum.

GasFlow

Baffle

Baffle

PFT - SIDE VIEW

Furnace waterwall cooling includes not only the furnace front wall, side walls, roof and floor, but thehigh heat duty screen tubes in front of the superheater as well. This unique boiler feature locates totalwater cooling where it can contribute most to keeping maintenance costs down. Each screen tube is asingle flow path between drums to assure proper circulation and cooling.

When B&W designed the PFI/PFT, every effort was made to minimize furnace refractory, a major maintenance area in boilers. Burners are located together on the furnace front (firing) wall, incorporatingfully water-cooled throats. As a result, there is no troublesome burner tile to point up or replace. The onlybaffle used in a PFI is located at the cool boiler outlet zone. The PFT has no hot refractory baffles, onlywater-cooled refractory, an alloy plate supported in the hot zone and an alloy plate in the cool zone.

For applications requiring extended steaming capacities, low draft loss or high gas flow conditions, thePFI can be arranged as a twin furnace by joining two opposite-hand PFIs side-by-side.

Typical gas flow through available generating bank arrangements

Baffle

Baffle Wall

GasFlowPFI - PLAN VIEW

Baffle

Baffle Wall

GasFlowPFI - TWIN PLAN VIEW

GasFlow

Baffle

A complete boiler bank assembly is moved into place for installation.

B&W takes full advantage of maximum shop assemblyof components. The furnace is shipped to the field in 10 to 15 pieces with all headers shop welded. Even the frontwall is shop assembled, complete with burners and windbox,saving time and money while assuring high quality control.

Features and Benefits: Furnace (Continued)

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PFI – PLAN VIEW GasFlow

GasFlow

GasFlowPFI – TWIN PLAN VIEW

BaffleBaffle

Baffle

Baffle Wall

Baffle Wall

Baffle

Baffle

PFT CROSSFLOW – SIDE VIEW

GasFlow

PFT - SIDE VIEW

Baffle

GasFlow

Baffle

PFT LONGFLOW – SIDE VIEW

GasFlow

Bottom support provides the most economi-cal arrangement and requires less headroom in the plant. Separate supports are located for the drums, superheater headers and furnace.Clearances, seals and supports are designed for known expansions in all directions from thefixed point.

The forces from normal operating positive furnacegas side pressures are contained by a system of buckstays comprised of tie bars and wideflange structural members. This buckstay systemaccommodates the effects of thermal expansion,temperature and pressure stresses, as well aswind and earthquake loading appropriate to the plant location. Because our buckstays are not welded to the furnace walls, weld tearsare eliminated.

Our furnace seal design provides a continuous gas-tight seal between the tube membrane anddrums. Where inner cased construction is used, a10-gauge plate is welded to the tie bars instead ofdirectly to the pressure parts. To maintain casingabove the dew point temperature, the plateis formed around the tie bar to ensure close plate-to-tube contact.

Recognizing the need to avoid departure fromnucleate boiling (DNB), our engineers havedesigned the furnace to achieve conservativeheat flux rates. For the same heat input, the PFI/PFT furnace has a heat flux rate less than half thatof a package-type boiler, making it especially tolerant of boiler water containing high silica and organics.

The PFT’s design allows furnace height to varyindependently of the boiler height. Therefore,a taller boiler bank is not required for a taller furnace.

Tie Bar

StandoffBar

Pin Tie Bar

BuckstaySupport Lug

End ConnectionAssembly Buckstay

Sidewall

RoofTubes

SealWeld

3/8 in. Dia.RND Bar

B&W’s PFI and PFT boilers are bottom supported to provide the most economical arrangement.

Buckstay arrangement

Roof seals provide a continuous gas-tight seal.

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Superheater Header Supports

Clips

Furnace Supports

Drum Saddle

Drum Foundation

Tie BarPin

StandoffBar

Tie Bar

End ConnectionAssembly

BuckstaySupport Lug

Buckstay

Sidewall

SealWeld

RoofTubes

3/8 in. Dia.RND Bar

Features and Benefits: Drums and Circulation

B&W PFI/PFT boilers are designed with extra-large steamdrums fit with the best available steam separating internals for high steam purity and positive circulation. Because theintent is to provide the driest steam possible for process orturbine, as well as the most solid recirculating water head, all PFIs and PFTs are equipped with B&W Cyclone SteamSeparators and two stages of downstream scrubbers.

Water

Steam

Steam andWater fromRisers

Baffle

B&W Cyclone Steam Separators provide the higheststeam purity and ensure positive circulation.

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Features and Benefits: Superheater

The superheater incorporates B&W’s proven multi-pass design for high steam velocities, assuringequalized cooling steam distribution in all circuits.This minimizes the need for high alloy steels, even inareas of highest temperature. Because the super-heater is positioned in a partial radiant heat zone, thesteam temperature characteristic of the PFI/PFTis nearly flat from about half load and higher. This affords close control of process heatingrequirements or turbine operation over a wideload range while minimizing attemperationrequirements.

Fully drainable superheaters, specially designedby B&W for PFI/PFT boilers, do not trap hydrowateror steam condensate. Compared to pendantsuperheaters that must be boiled clear, B&W’sdrainable design saves valuable time during startupwhile minimizing the chances of over-heat duringthe pressure-raising stage.

The PFI/PFT superheater circuits are completelywelded from header to header. All bends are precisely die formed; no cast or forged bends areused. Tube materials and thicknesses may be customized for special applications.

The PFI/PFT superheater also benefits from itspositive bottom support. This allows only minimumdifferential expansion relative to furnace floor tubes.Lateral tube supports maintain gas lane spacingand limit vibration. Headers are located in their ownvestibule, well out of the flue gas stream, and thesuperheater incorporates a convenient outlet con-nection at the operating-floor elevation.

The PFT superheater elements are spaced closertogether (4-1/2 in. center-to-center) compared withthe PFI (6 in. center-to-center). This means that thePFT can accommodate more rows of surface forthe same boiler width, making it a favorite for highsteam temperature requirements.

Dry Steam

Steam andWater from

Risers

Baffle

Steam-Free Water

Even when load changes and transientconditions are wide and frequent, B&W’sPFI/PFT steam drum internals and watercircuit design have been developed toassure positive circulation across theentire load range. The circulation designof the PFI/PFT has been developed so thatall high heat absorbing tubes are carefullyarranged as vertical upflowing circuits,and downcomer circuits are specificallylocated in the low gas temperature regionof the boiler.

Incorporating the use of B&W’s Cyclone Separator steam drum internals comple-ments the circulation design by providingexcellent steam purity and steam-freerecirculated water that assure adequatecirculation flow to satisfy the design conditions at all loads. The design of the boiler’s circulation system with the CycloneSeparator steam drum internals minimizesthe drum water level swings that can occurwith high-capacity boilers. With appropriatecontrols, the ample steam drum volumewith B&W internals can be designed tohandle a wide variation in load change.

When superheaters or special processesare required, steam with less than 1 ppmsolids can be obtained. Turbine blades arekept cleaner and costly superheater tubefailures caused by solids carryover are significantly reduced. The drum internal’sdesign also allows free end flow to minimizeturbulence and end-to-end level fluctuation.

Water tubes entering the drums are rolledinto specially grooved seats to providemore holding power and seal integrity asdemonstrated by over ten million rolledjoints worldwide. Tube joints operatingabove 1500 psig (103.4 bar) are sealwelded for additional seal integrity.

Tube Expandedinto Grooves

GeneratingBank Tube

Drum

Seal Weld(Over 1500 psi

Design Pressure)

Rolled tube joints and grooved tube seats provideexcellent holding power and seal integrity.

Saturated Connections

Steam Sampling

DrypanSecondaryScrubber

PrimaryScrubber

Normal Water Level

CycloneSeparators

1in.

ChemicalFeed

FeedwaterDistribution

PipeContinuousBlowdown

Downcomers Riser Tubes

Specially designed steam drum internalsenable rapid load changes.

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The integral air plenum concept designed into B&W’s PFI assures that installation at the plant is vastly simplified. The “straight-through” arrangement of the PFI/PFT boiler with a regenerativeair heater is the most common because it is the most functional. However, because the plenum (integral duct-flue surrounding the rear, top and front of the PFI) can be internally baffled to accommodate almost any duct inlet or flue outlet, an unlimited number of both air heater and economizer arrangements are possible. The PFT air duct is routed under the furnace floor. Bothplenum arrangements make operation easier and minimize space requirements.

A lower drum heating coil can be supplied to maintain the boiler in a hot standby condition, substantially reducing re-start time from a matter of hours to a matter of minutes. Thermal sleeveconnections, which eliminate stress from differential expansion, are standard.

A lower drum heating coil willreduce re-start time.

Lower Drum

ThermalSleeve

Heating Coil

Coil SupportBrackets

SteamIn

CondensateOut

Features and Benefits: Burners and Environmental Equipment

Designed primarily for natural gas and oil firing,the PFI/PFT is also used for incinerating a widerange of liquid and gaseous waste fuels, and asa heat recovery boiler for gas turbines. With multiple burners and suitable controls, self-sustaining fuels can be fired individually or in combination.

The burner wall is large enough to accommodatea wide range of burner types and configurationsincluding those of B&W’s design or others.

A portion of the combustion air can be introducedthrough sidewall ports located downstream of the burners to promote staged burning for lowerNOx emissions. Recirculated flue gas may beintroduced into the combustion air stream for

additional NOx control. The completely water-cooled firing wall absorbs additional heat fromthe gas, thereby limiting thermal NOx formation.

For the same input, the PFI/PFT furnace hasabout six times the volume of a package-typeboiler which better accommodates long flamelengths typical of today’s low NOx oil and gasburner technology.

B&W is responsive to ever-tightening requirementson airborne emission limits. Given the variety offuels that can be burned in the PFI/PFT, B&W willsupport your air emission requirements with add-on technology for control of acid gas, particulateand other specified compounds.

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Special Features Set the PFI/PFT Apart From Others

Lower Drum

Heating Coil

Steam In

CondensateOut

ThermalSleeve

Coil SupportBrackets

Master hand hole (MHH) fitting

Babcock & Wilcox DesignCompetitor’s Design

Seat Seat

Master Hand Hole (MHH) Fitting

3/8 in.Maximum

Header

Flexible BlockInsulation

Membrane Wall

InsulationSupport Tine

Self-Attaching Speed Nutwith Tine Bent Over

ProtectiveMetal Lagging

Membrane wall with block insulation and laggingenables indoor or outdoor installation.

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Special inspection doors for pressurizedoperation allow observation of both com-bustion conditions and cleanliness of heat-absorbing surfaces. Safety is providedby a special interlock that assures that compressed air is properly aspirating at theaperture before the door is opened.

Economizers and air heaters are available for increased efficiency. Pre-engineeredarrangements of extended surface or bare-tube economizers, as well as regenerative ortubular air heaters are offered to meet varyingfuel, space and economic considerations.

Sootblowers are properly located for effectivecleaning of the superheater and generatingbank heat transfer surfaces. Sootblower bearings, wallboxes and tube openings arestandard on all PFI/PFT boilers, regardless offuels fired.

PFIs firing oil or other ash-containing liquidshave boiler banks arranged for effective laneblowing via rotating-type sootblowers. Moltenoil ash normally will run off superheater tubesmaking sootblowers in this area unnecessary.Where a particular ash makes liquid-to-solidtransition at the entrance to boiler banks,retractable sootblowers can be located at thisarea. The PFT has wide cavities within the boilerbank to accommodate the number of soot-blowers necessary to handle especially toughcleaning requirements.

Wash-water troughs and drains are standardon every new PFI/PFT boiler to facilitate off-line water-washing.

Master hand hole (MHH) fittings are strategi-cally located in water and steam headerswhere access is required. The MHH fittingweld is designed to avoid cracking associatedwith stress build-up in the seat.

Indoor or outdoor operation are both madepossible by the all-metal lagging constructionwhich presents a good appearance, is quitedurable and requires minimal maintenance.

MHH fitting is un-seated whenweld cools and contracts, eliminating stress build-up

in the weld.

MHH fitting is seated tightly to header when weld cools and contracts, leaving weld stressed

and vulnerable to cracking.

Competitor’s Design Babcock & Wilcox Design

Master Hand Hole (MHH) Fitting

Seat Seat

Header3/8 In.

Maximum

Flexible BlockInsulation

InsulationSupport Tine

ProtectiveMetal Lagging

Membrane Wall

Self-Attaching Speed Nutwith Tine Bent Over

Total Scope Supply and Services

B&W’s extensive, worldwideexperience allows us the flexibility to easily meetdiverse project requirements –anything from a knock-downboiler to an entire steamisland. We can package yourboiler system with properlysized, quality auxiliaries tomatch your needs and ourstandards of excellence.

Stringent quality controlstandards

At B&W, quality assurance is integral to our design,engineering and manufac-turing processes. To ensureall codes and specificationsare met, B&W uses stringentquality control proceduresand sophisticated testingapparatus. Rigid standards

B&W’s manufacturing facilities maintainthe highest quality standards.

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have been established for ourmaterial suppliers as well.

B&W’s commitment to quality is evidenced by our:• Advanced technology –

B&W builds quality into its products during everyprocess and stage.

• Strength in size and capacity – facilities,manpower and global presence provide you with a complete range of fabricating processes.

• Outstanding responsive-ness – B&W is equippedand structured to meet your delivery needs and requirements.

Manufacturing and safety excellence

B&W PFI/PFT boilers are designed, engineered and manufactured at ourWest Point, Mississippi,USA facility. This plant isISO-9001 registered, ASMEcode approved and is in compliance with AWS coderequirements. B&W’s WestPoint plant also maintains an outstanding safety record andhas been awarded the OSHAStar Status in the VoluntaryProtection Program.Manufacturing and safetyexcellence are a continuousgoal for B&W.

Worldwide responsiveservice and manufac-turing support

B&W’s network of domesticand international sales repre-sentatives and field serviceengineers assures you of aprompt response – whetherservicing and upgrading yourexisting system or specifyingnew equipment. We canprovide services rangingfrom routine inspection andcontrols tuning to capacity

increase engineering studies,low emissions conversions, ornew digital control systems.

To meet the needs of theglobal market, we alsodesign, engineer and manu-facture PFI/PFT boilers inaccordance with all B&Wstandards through variousinternational operations andlicensees.

Support services

B&W believes that customersatisfaction and trust is builtby maintaining close contactwith the customer after thesale. In addition to equipmentsupply, B&W offers compre-hensive support servicesincluding:• Field service engineering• Inspection and maintenance

services• Engineered upgrades or

custom modifications• Long-term service

alliance programs• Training programs• Operating instructions• Spare parts manuals• Start-up and commissioning

services• Replacement part ordering

by phone or Internet24 hours a day

Reliable single-sourcesupplier

B&W’s proven expertise inboilers, burners and controlsmakes us a reliable andresponsive single source forPFI/PFT boilers and auxiliaryequipment. From engineeringand manufacturing to fieldconstruction, start-up andoperation, B&W knows howto make it all work togetherfor maximum operating efficiency and dependability.

A network of B&W field service engineers is available forcustomer support long after the sale is completed.

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The Babcock & Wilcox Company – we’re the original. We’ve been generating powerful solutions in the design, construction and servicing of steam generating systems since1867. So put our experience and capabilitiesto work for you today. Insist on us by name.

For more information, or a complete listing of our sales and service offices, call 1-800-BABCOCK (222-2625), send an e-mail to info@babcock.com, or access our Web siteat www.babcock.com.

The Babcock & Wilcox Company20 S. Van Buren AvenueBarberton, Ohio, USA 44203Phone: (330) 753-4511Fax: (330) 860-1886

Babcock & Wilcox Canada Ltd.581 Coronation BoulevardCambridge, Ontario, Canada N1R 5V3Phone: (519) 621-2130Fax: (519) 621-9681

The information contained herein is provided for general information purposes only and is not intended or to be construed as a warranty, an offer, or any representation of contractual or other legal responsibility.

Generating Powerful Solutions is a service mark of The Babcock & Wilcox Company.

© 2004 The Babcock & Wilcox Company. All rights reserved.A McDermott company.

E101-3186 3MD4J