SECA Solid Oxide Fuel Cell Program · Prereformer Air Fuel Feed Fuel Processing NOTES: 1. Optional liquid fuel feed for non-stationary applications Note 1 SOFC Core Anode Fuel Gas

SECASolid Oxide Fuel Cell Program

Nguyen Minh

3rd Annual SECA WorkshopWashington, DCMarch 21-22, 2002

3rd SECA WorkshopMarch, 2002

Program ObjectiveProgram Objective

• Approach– System approach– Development focus

�High performance� Low cost�Reliability�Modularity�Fuel flexibility

• Overall objective– Demonstrate a fuel-flexible, modular 3-to-10-kW solid oxide

fuel cell (SOFC) system that can be configured to create highlyefficient, cost-competitive, and reliable power plants tailored tospecific markets


SOFC System ConceptSOFC System Concept

36 IN.

15 IN.

20 IN.


Key System FeaturesKey System Features

• SOFC– High-performance reduced-temperature cells– Operation on light hydrocarbons– Tape calendering manufacturing process

• Fuel processor– Low-cost, fuel-flexible fuel processor design– Catalytic process– Pre-reforming function

• Other subsystems– Integrated thermal management– Flexible control subsystem


Program FeaturesProgram FeaturesDEM O NSTRATIO NO F FUEL FLEXIBLE

PROTO TYPESYSTEM

PROTO TYPEDEM O NSTRATIO N

TECH NO LO G Y IM PRO VEM ENTAND CO ST REDUCTION

PACK AG ED SYSTEMDEM O NSTRATIO N

TECH NO LO G Y ADVANCEM ENTAND CO ST REDUCTION

FIELD TEST O FPACK AG ED SYSTEM

SELECTEDAPPLICATIONFOR PHASES

II, III

DEM O NSTRATIO NO F PACK AG ED SYSTEM

FO R SELECTEDAPPLICATIO N

FIELD TEST O FPACK AG ED SYSTEMFO R SELECTEDAPPLICATIO N

• IMPROVED PERFORMANCE, YIELDS,EFFICIENCY

• ENABLE INCREASED MANUF.AUTOMATION

• DESIGN PACKAGING

PH ASE I PH ASE II PH ASE III

DESIGN, STACK DEVELOPMENT,FUEL PROCESSING, THERMAL MANAGEMENT,CONTROLS/SENSORS, POWER ELECTRONICS

K EY TECH NO LO GY DEVELO PM ENT

• ADVANCED MATERIALS/ PROCESSES• ENABLE FULL MANUF. AUTOMATION• OPTIMIZE PACKAGING

MARKETANALYSISAND COSTESTIMATES

MARKETANALYSISAND COSTESTIMATES

COSTESTIMATES


Phase I Work ElementsPhase I Work Elements

• System analysis

• Cost estimate

• Stack technology development

• Fuel processing

• Thermal management

• Control and sensor development

• Power electronics

• System prototype demonstration


Schematic of Method for Cost EstimationSchematic of Method for Cost Estimation

Define SystemIdentify Components

Establish Performance Specifications

Size Components

Identify BOP Suppliers/Manufacturers

Calculate Costs

Solicit Cost Information

Perform System Cost Estimation

Map Manufacturing Process

Design Stack, Fuel processor

Stack and Fuel ProcessorBOP Components

Determine Production Rates

Raw Materials CostEquipment CostLabor CostFacilities/Utilities Cost

VendorsHoneywell Businesses

Engineering Judgement

Assembly Costs


Key AssumptionsKey Assumptions

• Main system design assumptions– 5 kW stationary system operating on natural gas– Fuel processor as pre-reformer

• Key manufacturing assumptions– Production rate of 250 MW/year– Single plant located in Southwest


Cost EstimatesCost Estimates

• Projected system cost when fully developed:$388/kW

• Stack Costs

Equipment (18.7%)

Labor (12.1%)

Materials (50.5%)

Land & Building (0.9%)

Utilities (17.8%)


System ConceptSystem Concept

Air Feed

PWater Feed

Natural Gas Feed

System Exhaust

Water Filtration

Hot Exhaust Gas

P

C

Fuel Mix Preheater/VaporizerLiquid Fuel

Inverter

C

Fuel Cell Air

Prereformer Air

Fuel Feed

FuelProcessing

NOTES:1. Optional liquid fuel feed for non-stationary applications

Note 1

SOFCCore

Anode Fuel Gas

Stack with Air Preheating

DCPower

ACPower


System Design and Analysis ApproachSystem Design and Analysis Approach

• Propose Conceptual Design• Steady-state Model• Assume Components &Performances• Detailed Thermal/TransientSystem Model

• DesignComponents• System Analysis• Trade Studies

• Compare to Requirements• Identify Gaps

ConceptualSystem Definition

TechnologyGaps

System Definition

TechnologyDevelopment

System RequirementsTechnology Base


Performance EstimatesPerformance Estimates

Stationary Mobile Military

Fuel Natural Gas Gasoline Diesel

StackVoltage, VUtilization

0.750.80

0.750.80

0.750.80

PowerFuel cell, kWNet, kW

5.75.0

5.95.0

6.15.0

EfficiencyNet, % 40 33 30


Low Cost Manufacturing ProcessLow Cost Manufacturing Process

• Fabricationprocess withtape calendering

• Multilayer electronicsfabrication process


Fracture SurfaceLaMnO3Cathode

ZrO2Electrolyte

NiO/ZrO2Anode

Thin Electrolyte CellThin Electrolyte Cell


Stack ConfigurationsStack Configurations

• Thin film electrolytes• Thin foil metallic interconnects• Gas manifold options• Gas flow configuration flexibility

• Thin film electrolytes• Thin foil metallic interconnects• Gas manifold options• Gas flow configuration flexibility

Crossflow Design Radial Flow Design Unitized Cell Design


SOFC PerformanceSOFC Performance

0

0.2

0.4

0.6

0.8

1

1.2

1.4

0 0.5 1 1.5 2 2.5

Current Density (A/cm²)

Vo

ltag

e (V

)

0

0.2

0.4

0.6

0.8

1

1.2

1.4

Po

wer

Den

sity

(W

/cm

²)

Voltage in Syngas

Power Density in Syngas19% H2, 24% CO, 1% CO2, Bal N2

Power Density in H2

Voltage in H2

• 800°C operation• Open circuit voltages

in agreement withtheoretical values

• Peak power density:– 1.3 W/cm² in hydrogen– 0.85 W/cm² in JP-8

syngas

• 800°C operation• Open circuit voltages

in agreement withtheoretical values

• Peak power density:– 1.3 W/cm² in hydrogen– 0.85 W/cm² in JP-8

syngas


SOFC Cell Performance at Reduced TemperaturesSOFC Cell Performance at Reduced Temperatures

0

0 .2

0 .4

0 .6

0 .8

1

1 .2

1 .4

0 0 .5 1 1 .5 2 2 .5 3

C ur rent D ens ity , A/c m 2

Cel

l Vol

tage

, V

0

0 .2

0 .4

0 .6

0 .8

1

1 .2

1 .4

Pow

er D

ensi

ty, W

/cm

2

800C

750C

700C

650C

600C

Hydrogen fuel

Air oxidant

High power densities (e.g., 0.9 W/cm² at 650°C) achieved at reducedtemperatures (<800°C) with anode-supported thin-electrolyte cells

High power densities (e.g., 0.9 W/cm² at 650°C) achieved at reducedtemperatures (<800°C) with anode-supported thin-electrolyte cells


0.4

0.5

0.6

0.7

0.8

0.9

1

1.1

1.2

0 20 40 60 80 100 120

Time, H

Cel

l Vo

ltag

e, V

780

785

790

795

800

805

810

815

820

Cel

l Te

mp,

C

V C

75% Fuel Utilization, J=1.72A/cm2

Power Density = 1.1 W/cm2 80%

85%Fuel: Hydrogen

Oxidant: Air

Cell Fuel UtilizationCell Fuel Utilization


Other Cell/Stack AccomplishmentsOther Cell/Stack Accomplishments

• Demonstration of high cell performance (1.8 W/cm2

at 800°C) with high utilization (50%)• Operation of a stack module for more than 3000

hours– Identification and modeling of degradation rate

• Fabrication scaleup and improvement


Reforming OptionsReforming Options

STEAMREFORMING

PARTIAL OXIDATION

AUTOTHERMALREFORMING

Fuel ReformerFuelSteam

H2, CO2

AirFuel Fuel Reformer H2, CO, CO2, H2O, N2

Fuel ReformerFuelSteamAir

H2, CO, CO2, H2O, N2


Fuel Processing ApproachFuel Processing Approach

• Fuel processor as a pre-reformer for hydrocarbonfuels

• Approach: Catalytic partial oxidation (CPOX) asbaseline and process modifications as required fordifferent types of fuels


CPOX for Processing Hydrocarbon FuelsCPOX for Processing Hydrocarbon Fuels

• Fuels: propane, butane,octane, JP-8, and diesel

• Duration: 700 hours to date

• Thermal cycles: 10

• Sulfur tolerance: 1000 ppmdibenzothiophene in JP-8

• Yield: 70-80% of LHV in JP-8

• Fuels: propane, butane,octane, JP-8, and diesel

• Duration: 700 hours to date

• Thermal cycles: 10

• Sulfur tolerance: 1000 ppmdibenzothiophene in JP-8

• Yield: 70-80% of LHV in JP-8

0%

20%

40%

60%

80%

100%

0 40 80 120 160 200 240 280 320

Time (Hours)

Per

cen

t Y

ield

%

H2

COThermal Cycle


Control System FunctionsControl System Functions

– Control system functionality drives integration– Coordinate subsystems for shared resources

and efficient operation– Efficiently regulate over a wide operating range

� Flow / Composition� Temperature� Pressure� Power

– Provide safe system operation through built-intest

– Perform process and component healthmonitoring for improved life cycle

– Provides user interface and automated systemoperation� Startup/ Shutdown� Scheduled operation� Status indicators/alarms� Emergency Shutdown

Operational ModeInputs

Com

man

d fl

ow

System-level control

Subsystem

Subsystem

Subsystem


Control & Sensing ApproachControl & Sensing Approach

– Honeywell’s proprietary Fuel Cell DynamicComponent Library allows for rapiddevelopment of dynamic system models andprototyping of control systems throughsimulation.

– Rapid prototyping capabilities allow fordirect transfer of controls designed insimulation to control of fuel cell system.

– Advanced control and sensing techniquescan investigated through simulation tradestudies and then the most promisingapproaches easily implemented in hardwaresystem.

PlantSensors

Feedback

Feedforward

Estimation

Controls

Rapid Prototyping


Controls Analysis and Design ProcessControls Analysis and Design Process

Control Requirements Definition•Model Development•Subsystem Analysis•Control Loop Analysis•Cell Monitoring

Preliminary Control Design•Simulation Based Design•Assume Component Performance•Controllability of System Addressed

Control Evaluation and Development•Control Design Trade Studies•Focus Control Design for Application•Built-In Test and Health Monitoring•Final Control Design for Phase I•Develop Sensor Requirements•Develop Actuator Requirements

Sensor and Actuator Evaluation•Sensor Trade Studies•Sensor Testing•Actuator Trade Studies•Actuator Testing

Sensor and Actuator Development•Sensor Development•Actuator Development

Control System Integration•Rapid Prototyping System Implementation of Control Strategy•Hardware Selection and Procurement•Software Development•Hardware/Software Implementation

SystemDesign

-FMEA -Event Ledger . . .

“Design for Control”

Current Effort


Concluding RemarksConcluding Remarks

• SECA SOFC system concept• System features

– High performance– Low cost– Flexibility

• Various activities to support system development

Documents

SECA Solid Oxide Fuel Cell Program · Prereformer Air Fuel Feed Fuel Processing NOTES: 1. Optional liquid fuel feed for non-stationary applications Note 1 SOFC Core Anode Fuel Gas