Power Division Retrofit Primer

Rob Schmitz

Western Regional Sales Manager

Goals for Today

Industry History

Key definitions

Information required to assess a retrofit opportunity

Retrofit considerations

Retrofit examples

Special Cases

Rules of Thumb

Why Retrofit a Boiler?

NOx reduction

Fuel conversion and/or addition

Capacity change (de-rate)

Improve efficiency

General upgrade

Equipment is failing

Correct sins of the past

Retrofit cost less than buying a new boiler

Industry History

1950’s First package boiler systems manufactured

1970 Clean Air Act passed

1980’s Package boiler emissions regulated requiringimproved technology

1990’s Low NOx technology w/FGR standardized

2000-2010 Ultra Low NOx technology standardized

2010-Pres Emission and Efficiency gains

Definitions

Flue Gas Recirculation (FGR)

FLUE GAS is the products of combustion that

leave the boiler via the stack

FLUE GAS RECIRCULATION (FGR) is the

blending of a portion of the flue gas with

fresh air prior to entering the burner

FGR is a standard NOx reduction method

Induced and forced (dedicated fan) systems

Flue Gas Recirculation (FGR)

FGR NOx Reduction

Low NOx Burners

Technology capable of 30ppm NOx w/FGR

firing natural gas

Utilizes air/fuel staging techniques to

reduce flame temperature and the

formation of thermal NOx

Flame envelope must be evaluated

Ultra Low NOx Burners

Technology capable of

Combustion Control Systems

Metering▪ Measuring air and fuel flow▪ Cross limiting (air leads fuel)▪ Oxygen trim

Parallel Positioning (PP)▪ Separate air and fuel actuators▪ Position feedback linked to BMS▪ Oxygen trim

Single Point Positioning (SPP)▪ Air and fuel control rigidly linked to a single

actuator▪ Rental boilers and older systems

Draft Systems

Forced Draft (FD Fan)

▪ Package & Field Erected Boilers

Induced Draft (ID Fan)

▪ Field Erected Boilers

Balanced Draft (FD & ID Fan)

▪ Field Erected Boilers

▪ Common Stacks

Natural Draft (No Fans)

▪ Process Heaters

Sales & Engineering

Information Required for a Burner Proposal

Operation requirements

Emission requirements

Boiler performance datasheets

Boiler furnace drawings

Fuel types

Fan curves

System P&ID’s

Equipment arrangement drawings

Information on existing equipment

Site requirements

Retrofit Considerations

New vs. Original operating conditions

Evaluate auxiliary equipment

Evaluate burner selection vs. furnace details

Evaluate draft system

Fuel conversion

Boiler impact study

Equipment arrangement

Environment

Plant historian

Package Boiler Furnace

Field Erected Furnace

Evaluating Draft Systems

System draft losses (Burner, Furnace, Ducting, Eco/APH, etc.)

Controlling combustion air flow (VFD and dampers)

FD Fan overages (10% flow & 21% static @ max ambient)

Addition of FGR/OFA

Turndown

Ducting

Stack height

Flow modeling

Boiler Impact Study

3rd Party

Field erected boilers

Develop a baseline of current boiler operation

Develop a baseline with new conditions such as a fuel change

Determine if specified boiler design or operating parameters areexceeded and address accordingly

Evaluate pressure parts

Evaluate superheater

Evaluate auxiliary equipment for new conditions

Vibration analysis

Retrofit Examples

Hospital

Three (3) Nebraska D type Boilers

Steam Capacity: 30,000 pph

Natural Gas or #2 Oil firing

1990’s Burner System Existing

Single Point Positioning Control

Designed for 30ppm NOx w/20-25% FGR firing gas

Need to meet 9ppm NOx firing gas

Hospital

Zeeco FreeJet ULN Burner

PLC Based BMS

Metering Combustion Controls

New FCV’s, flowmeters and actuators

Reuse windbox and FD fan

Reuse safety valve trains

Hospital

Power Plant

Two (2) Field Erected Boilers

Steam Capacity: 150,000 pph

Primary Fuel: Coal via a stoker

Aux Warm-up: Natural Gas/#2 Oil

Convert to 100% NG or #2 Oil firing

Abandon coal firing capability

Power Plant

Power Plant

Power Plant

Power Plant

(2) Zeeco GB Gas/Oil Burners

Common Windbox

Valve Trains

Airflow Modeling

2 Fired as 1

NOx (NG): 80 ppm (0.1 lb/MM Btu)

New FD fan, BMS & CC by others

Power Plant

Bonus Material

Combustion Air Pre-heater existing?

Old method of heat recovery

Field erected and larger watertube boilers

Boiler exhaust heats combustion air

Retrofit with an economizer heating boiler feedwater

Economizer more efficient

Firing with ambient air lowers baseline NOx

Part of overall NOx reduction strategy

Combustion Air Pre-heater existing?

Are you considering an SCR?

Selective Catalytic Reduction (SCR)

Designed for

Do I need a new burner?

Z-jet fuel carriage retrofit

Reuse air register

Fuel conversions

No throat modifications

Low NOx upgrade

Improved turndown

Do you need Draft Controls?

NFPA 85 Boiler and Combustion Systems Hazards Code

Boiler/Burner Industry Design Guideline

Definitions

Outlines how to safely start-up and shutdown a boiler

Types of combustion controls

Types of ignition systems

System P&ID’s

Addresses different types of boilers

Zeeco Power Brochure

Available at www.zeeco.com

http://www.zeeco.com/

Slide 1 Power Division Retrofit PrimerGoals for TodayWhy Retrofit a Boiler?Industry HistoryDefinitionsFlue Gas Recirculation (FGR)Flue Gas Recirculation (FGR)Low NOx BurnersUltra Low NOx BurnersCombustion Control SystemsDraft SystemsSales & Engineering Information Required for a Burner ProposalRetrofit ConsiderationsPackage Boiler FurnaceField Erected FurnaceEvaluating Draft SystemsBoiler Impact StudyRetrofit ExamplesHospitalHospitalHospitalPower PlantPower PlantPower PlantPower PlantPower PlantPower Plant Bonus MaterialCombustion Air Pre-heater existing?Combustion Air Pre-heater existing?Are you considering an SCR?Do I need a new burner?Do you need Draft Controls?NFPA 85 Boiler and Combustion Systems Hazards CodeZeeco Power BrochureSlide 38