Development and Demonstration of a New Generation High-Efficiency 1-10 kW Stationary PEM Fuel Cell Power System
Durai Swamy, Ph.D.
Intelligent Energy
June 12th, 2008
This presentation does not contain any proprietary, confidential, or otherwise restricted information
Project FC39
OverviewTimeline
−Start: July 2007−End: July 2010−25% complete by 4/08
Budget−$4.4 million budget−50% DOE cost share
−$322K received FY07−$450K projected for FY08
Barriers
Partners−Intelligent Energy, Inc. (lead)−Intelligent Energy, Ltd.−University of South Carolina−California State Polytechnic
University, Pomona−Sandia National Labs
Targets Project DOE 2011
Electrical Eff. 40% 40%
Overall Eff. > 70% 80%
Durability 40,000 hrs 40,000 hrs
Capital Cost $400 / kW $750 / kW
ObjectivesDevelop and demonstrate a PEM fuel cell based stationary power system that provides foundation for commercial, mass produced units that address identified technical barriers
• Technical objectives−40% electrical efficiency (fuel to electric energy
conversion)−70% overall efficiency (fuel to electric energy + usable
waste heat energy conversion)−Potential for 40,000 hour life−Potential for $450/kW
• Topic 7A – International Partnership for a Hydrogen Economy (IPHE)−Engage international partners−Demonstration phase in an IPHE country other than USA
Milestones
Milestone: Evaluation of adsorbent materials for use in adsorption enhanced reformer completed; initial tests with high pressure membrane reformer completed
Go/No-Go Decision: Validation of hydrogen generation and fuel cell performance improvements demonstrating the viability of achieving a 40% electrical efficiency for the system will be complete. A Go decision will be followed by proceeding to development and testing of a prototype PEMFC power system.
July 2008
January 2008
Contract signed and project launchedJuly 2007
Milestone or Go/No-Go DecisionMonth/Year
ApproachOpen architecture – high purity hydrogen interface between fuel cell, fuel processor
−Increase cell voltages−Increase
hydrogen generation thermal efficiency−Decrease
parasitic loads0.60
0.65
0.70
0.75
0.80
0.85
0.90
60% 65% 70% 75% 80% 85% 90%H2 Generation Eff, %
Ave
rage
Fue
l Cel
l Vol
tage
, V/c
ell
15% Parasatic Power10% Parasatic Power5% Parasatic Power
CHP A
CHP B
CHP C
Design points above line
exceed 40% efficiency
Design points below the linedo not achieve 40% efficiency
Note: H2 generation efficiency is for high purity hydrogen not reformate. A typical 85% efficient reformate and 75% anode fuel utilization would imply a 64% H2 generation efficiency.
ApproachFuel cell stack and system
−Improved flow field design−Fluid flow modeling−Advanced MEA design−Diffuser optimized for water
management−Advanced bipolar plate
materials −Reduced air pressure
requirements−Pressed plate architecture to
address cost−Optimized air delivery design−Optimized power management
design & configuration
Hydrogen generationEthanol reforming - Two platforms in development−MesoFuel advanced membrane
reactor (< 2 kWe)− Increase reactor pressure− Thermal integration
improvements
−Hestia with rapid cycle PSA (> 2 kWe)−With 100mV fuel cell voltage
improvement, efficiency target can be reached with optimization of current Hestia design
−With 20mV fuel cell voltage improvement, efficiency target can be reached with integration of CO2 adsorption (AER) into Hestia process
0.0
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1.0
0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 1.10
Current Density/A cm-2
Cell
Voltage/V
0
14
28
42
56
70
84
98
112
126
140
Cell
Pow
er/
W
Combined technology developmentsBenchmark
Technical AccomplishmentsPEMFC – single cell performance improvements
Improvements show cumulative effects of new MEA, cooling architecture and diffuser material
Technical AccomplishmentsPEMFC – reduced system parasitic loads
High efficiency DC/DC converter development• High voltage converter for compressor operation• Low voltage converter for battery charging and
auxiliaries• Data indicate efficiencies of 95+% may be possibleCurrent work and next steps• Test the converter in a system• Test self-start operation
0%
10%
20%
30%
40%
50%
60%
70%
0 2 4 6 8 10 12net output power/kW
effic
iency
LH
V H
2
Baseline SystemBaseline StackJan 08 SystemJan 08 StackApril 08 SystemApril 08 Stack
Net Electrical Efficiency
Gross Electrical Efficiency
Technical AccomplishmentsPEMFC – forecast fuel cell system performance improvement
Data show potential system efficiencies based on:•Improved fuel cell performance •Reduced compressor power•Unregulated DC voltage output
57.4% efficient at 6kWe (baseline = 50%)
Technical AccomplishmentsHestia reformer - new reactor design
• Designed for ease of manufacture, assembly• Reduced pressure drop across combustor/flue gas path• Enhanced thermal integration• Streamlined balance of plant• Increased operating pressure / H2 recovery• Status−Fabrication, assembly completed fall 2007−Testing initiated December 2007−Initial ethanol tests performed January 2008−Preparing for next phases of tests April 2008
Technical AccomplishmentsHestia reformer – initial results
−New reformer reactor has been tested as standalone system, using simulated PSA off-gas as heat source−Results to left show expected H2
generation efficiency b d f based on reformer test results + potential PSA recoveriesrecoveries
Technical AccomplishmentsMeso reformer – performance mapping of single module completed
T = 575 – 640 CPfeed = 70 – 175 psigPprod = 5 psig – 500 mbarS/C = 4.5
Metric TargetStatus(4/15/08)
H2 purity > 99.9% > 99.9%
Thermal efficiency > 70% 65 - 67%
H2 production, slpm
5-6(10 module)
0.6 @ 65 -67% efficiency(single module)
H2 flux, sscm/cm2 15-20 15-17
Technical AccomplishmentsMeso reformer – summary of flux and efficiency
•Purity > 99.99%•Also demonstrated methane reforming•Stable operation achieved
Technical AccomplishmentsAER – dynamic model for AER process steps (U South Carolina)
PSA model adapted to PSA model adapted to include reforming reactions
Model has informed experimental apparatus designs
• Bed sizing• Cycle times• Temperatures• CO2 breakthrough• Purge gas requirements
Status: Calibrating model with experimental results. Model breakthrough times are similar to test data
– include reforming reactions– Model has informed experimental apparatus
designs• Bed sizing• Cycle times• Temperatures• CO2 breakthrough• Purge gas requirements
– Status: Calibrating model with experimental results. Model breakthrough times are similar to test data
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0 30 60 90 120 150 180 210 240
TOS [min]
Volu
me
frac
tion
CH4N2H2COCO2
All gases but CO2 get instantly purged out of the bed
Methanation with H2 and sorbed CO2
AER
N2
Pur
ge
H2+
Ste
am
TOS, min
Technical AccomplishmentsAER –experimental proof of concept
The above chart demonstrates four consecutive AER cycles successfully demonstrated on small reactor with ethanol‐water mixture (S/C=6, 70 psig)
Reformate Composition of 33 wt.% SR-1 / Pural MG70 with 20% K2CO3
0
20
40
60
80
100
0 30 60 90 120 150 180 210 240TOS [min]
Con
cent
ratio
n [v
ol.%
]
H2CH4COCO2
N2
H2+H2O EtOH+H2O
N2 N2 N2
EtOH+H2O EtOH+H2OH2+H2O H2+H2O H2+H2O
− Chart shows consecutive cycles with Ethanol on larger reactor (S:C =4.5)
− Table below is total cycles on larger reactor through May 2008
− e
Technical AccomplishmentsAER – full scale experimental results with integrated combustor
−Currently evaluating cycle timing, temperature profiles, heat balance
−Reactor and test stand specifications:−Natural gas or ethanol−1 to 5 kWe−Regenerate with nitrogen,
steam or other−All heat provided by
combustion−Measure H2 production
enhancement as well as CO2
breakthrough in bed
Technical AccomplishmentsAER – novel adsorbent materials (Cal Poly Pomona)
−Amorphous magnesium oxide (MgO) ambigel and xerogel materials
−Significant potential for increased adsorption capacity
−Status:−Several batches synthesized and
currently being analyzed by IE−Further batches planned
SEM of monolithic MgO aerogel(left) and xerogel (right)
Technical AccomplishmentsSystem level performance assessment (Sandia)
• Collaboration with Sandia National Labs to assess potential performance of possible system architectures
• Part of Sandia’s contribution to IEA-HIA Task 18
e-Load
ReformerSeparation
(PSA)
Batt
PowerManage
FCHeatRecovery
H2 Storage
Heat Load
Retentate
SyngasFuelH2OAir
AirQ
H2
H2
We
We Flue
KO water
Flue
• Status (4/15/08):• Collaboration launched in March 2008• System model adapted to capture IE’s
approach• Initial results show 35% fuel-to-
electric efficiency based on historical Hestia reformer data, new fuel cell data and parasitic power losses
• Next steps• Consider other system architectures• Continue to update models with
experimental data• Form basis for go/no-go in July 2008
Future WorkFY08
• Go/No-Go (July 2008): Determine system architecture leading to reaching technical objectives• Go decision will be followed by proceeding to development
and testing of a prototype PEMFC power system
FY09• Milestone (January 2009): Complete engineering
design of integrated power system• Milestone followed by in-house system testing
• Go/No-Go (July 2009): Validation of the prototype power system’s ability to meet performance targets will be complete• Go decision will be followed with continuing to the field
demonstration of this system
Summary −Approach: Develop portfolio of technologies in Project Year 1 (Jul-07 – Jul-08) to determine best architecture for meeting DOE objectives for stationary fuel cell power
−Partners−IE in US (lead) & UK−U of South Carolina−Cal Poly Pomona−Sandia Nationa Labs
−Future work: Down-select technologies then engineer, test and demonstrate new generation PEMFC power system
System BaselineStatus(4/15/08)
Fuel cell system efficiency
50% 57%
Hestia hydrogen generator
Sophisticated mechanical design
Design for manufacture and assembly
Mesohydrogen generator efficiency
50% 65 – 67%
Adsorption enhanced reformer
Concept on paper
Experimental proof of concept
Summary of technical progress highlights
