high temperature fuel cell tri-generation of power, … temperature fuel cell tri-generation of...

© National Fuel Cell Research Center, 2012 1/22

High Temperature Fuel Cell Tri-Generation of Power, Heat & H2 from Biogas

Jack Brouwer, Ph.D. June 19, 2012

DOE/ NREL Biogas Workshop – Golden, CO


Outline

• Introduction and Background

• Tri-Generation/Poly-Generation Analyses

• OCSD Project Introduction


Introduction and Background • Hydrogen fuel cell vehicle performance is outstanding

• Energy density of H2 is much greater than batteries • Rapid fueling, long range ZEV

• H2 must be produced • energy intensive, may have emissions, fossil fuels, economies of scale

• Low volumetric energy density of H2 compared to current infrastructure fuels (@ STP) • H2 handling (storage, transport and dispensing) can be energy and

emissions intensive

An emerging strategy is poly-generation of hydrogen, heat and power from a

high-temperature fuel cell (HTFC)

There is a need for a distributed, high-efficiency, low emissions hydrogen

production method able to use a variety of feedstocks


Tri-Generation Energy Station Concept 1, 2, 3

Locally available

feedstock: Natural Gas,

ADG, Landfill Gas, ….

Electricity Heat

Hydrogen

Energy Station Concept Introduction and Background

1 Brouwer et al., 2001; 2 CHHN Blueprint Plan, 2005; 3 Leal and Brouwer, 2006


Introduction and Background Poly-generation of Power, Heat and H2

• Advantages: 4, 5, 6

• H2 production is at the point of use averting emissions and energy impacts of hydrogen and electricity transport

• Fuel cell produces sufficient heat and steam as the primary inputs for the endothermic reforming process

• Synergistic impacts of lower fuel utilization increase overall efficiency (i.e., higher Nernst Voltage, lower polarization losses, lower cooling requirement and associated air blower parasitic load)

• Potential Disadvantage: • Distributed production may not be compatible with carbon

sequestration

4 Leal and Brouwer, 2006; 5 O’Hayre, R., 2009; 6 Margalef et. al, 2008


High Temperature Fuel Cell (HTFC) Stack • Solid Oxide Fuel Cell Example

Introduction and Background

CH4+H2O 3H2+CO 2H2+O2- 2H2O + 4e-

O2 + 4e- 2O2-

Electrolyte

Reformation rxn

Fuel cell rxn

AN

C

ATH

load

Stack Operating Temperature Range = 650oC to 950oC

HE

AT

{CH4, H2O}

O2 Depleted Air

O2(Air)

{H2, CO, CO2}

{H2}

HE

AT

• Fuel Utilization Factor (Uf) = ~ 85%

• Air Utilization Factor = ~ 15 %

~ 60%

~ 30%

O2-


Outline





Recall: High Temperature Fuel Cell (HTFC) Stack • Molten Carbonate Fuel Cell Example

Analyses of Synergies

CH4+H2O → 3H2+CO 2H2+2CO3

2- → 2H2O + 2CO2 + 4e-

O2 + 2CO2 + 4e- → 2CO3

2-

Electrolyte

Reformation

Electrochemistry

AN

C

ATH

load

Stack Operating Temperature Range = 550oC to 650oC

CH4, H2O

O2 Depleted Air

O2, CO2

H2, CO, CO2

HE

AT

2CO32-

Air Flow and parasitic blower power can be reduced

Endothermic

Exothermic


~

C.C.

CH4 Air

Exhaust gases

1

Water

S O F C

2

3

4

7 8

9

6

5 CH4

H2 H2O

Reformer

(1)

CH4

H2 H2O

Reformer

(2)

CH4

H2 H2O

Reformer

(3)

CH4

H2 H2O

Reformer

(4)

~

C.C.

Exhaust gases

1

S O F C

2

3

4

7 8

9

6

5 CH4

H2 H2O

Reformer

(1)

CH4

H2 H2O

Reformer

(2)

CH4

H2 H2O

Reformer

(3)

CH4

H2 H2O

Reformer

(4)

Placement of a reformer in different locations: Configuration 1 reformer after the air preheater, Configuration 2 reformer after the water preheater, Configuration 3 reformer after the natural gas preheater, Configuration 4 reformer after the combustion chamber.

Cycle Configurations Air Water Natural Gas


Configuration 5: External reforming with combustion chamber after the air preheater.

15

~

S O F C

H2 H2O

C.C.

Water Air

7

10

CH4

CH4

8

3

2

9

4 6

REF

11 12 Exhaust gases

13

14 16 5

1

Configuration 6: Internal reforming

1

C.C.

~

S O F C

H2

8 7

13 9

H2O CH4 Air

Exhaust gases 11

12

2 6 4

5 3

10

Cycle Configurations


Thermodynamic Analyses • Energy performance analysis


0

1000

2000

3000

4000

5000

6000

7000

8000

00.10.20.30.40.50.60.70.80.9

11.11.21.3

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000

Pow

er D

ensi

ty [W

/m2]

Cel

l vol

tage

[Vol

ts]

Current Density [A/m2]

Electrochemical heat at different utilization factors (P=5000 A/m2)

0.4 0.6 0.8 EMF 0.4 0.6 0.8

Poly-Generation Analyses

Electrochemical Heat

]kW[hΔnV

)VV(Heat fHmax

cellmax2

−

=

• Synergy #1: Electrochemical heat & voltage

Fuel Utilization Values


• Electrochemistry & Reformation Synergy #2 – Air Flow

30

40

50

60

70

80

90

100

0.4 0.5 0.6 0.7 0.8

Air f

low

in [k

mol

/hr]

Fuel Utilization Factor

Factor #1 electrochem.

heat


Factor#2 reformation

cooling


• EXAMPLE: Efficiency of a Poly-Generating Hydrogen Energy Station (H2ES) without valuing heat


Electricity production with state-of-the-art

natural gas combined cycle

Centralized SMR Plant

(H2 production)

(Case: H2ES) Poly-generating

HTFC

Fuel

Fuel

Fuel

Electricity

Hydrogen

η el,1 = 61.2%η el,2 = 51.7%η el,3 = 58.4%

η H2,1 = 80.9%η H2,2 = 54.9%η H2,3 = 83.5%

η el,pp = 60%

η H2,SMR = 79%

ηtot = 69.5%


Poly-Generation Dynamic Analyses

0 0.2 0.4 0.6 0.8 10

250

500

750

1000

Pow

er [k

W]

0 0.2 0.4 0.6 0.8 10

20

40

H2 in

Tan

k [k

g]

12:00 AM 6:00 AM 12:00 PM 6:00 PM 12:00 AM0.5

• Diurnal dynamic operation of SOFC • Hydrogen tank fills forcing end of tri-generation • Control of system temperatures during transient is possible

12:00 AM 6:00 AM 12:00 PM 6:00 PM 12:00 AM950

1000

1050

1100

1150

1200

1250

1300

Tem

p [K

]

Tan,in Tca,in Tca,out Tan,out


Outline





STORAGE TANK

ADG

HOT WATER

HEAT EXCHANGER ANAEROBIC

DIGESTION GAS HOLDER

SLUDGE

DIGESTER

BOILER

HYDROGEN HYDROGEN STORAGE

HYDROGEN DISPENSER

FUEL TREATMENT

AC POWER

HIGH-T FUEL CELL

World’s First Demonstration • Orange County Sanitation District

• Euclid Exit, I405, Fountain Valley

• Support: DOE, ARB, AQMD

Renewable Tri-Generation of Power, Heat & H2

Sponsors/Participants:


OCSD Project – World’s First • Installation complete, Operation on natural gas (6 months),

ADG operation underway for ~1 year

Renewable H2 Filling Station

ADG fueled DFC-H2 ® Production Unit


FCE Equipment

Air Products Equipment

Anode Exhaust

Skid

DFC (Direct

Fuel Cell)

ADG Clean-up Skid

Syngas Compressor

Skid PSA Skid (pressure swing

absorption)

Compressor Skid

Hydrogen Storage Tubes

Inverter &

Electrical BoP

Mechanical BoP


OCSD Project – Status Update As of December 31, 2011: • Operation on natural gas from January 1, 2011 • Installation completed in June, 2011 (including ADG skid) • Operation on ADG: 3,522,591 SCF processed & used • Electricity produced: 605,512 kWh • Hydrogen produced: 6,400 lbs (2,902 kg) • Steady-State performance demonstrated

• Significant challenges with grid interconnection, power quality, inverter trips that adversely affect performance

Method Efficiency

Total Efficiency (Elec. + H2) 53.2%

Eq. Hydrogen Efficiency 87.0%

Eq. Electrical Efficiency 37.4%

The UC Irvine Team

Credit: Steve Zylius/UC Irvine Communications

high temperature fuel cell tri-generation of power, … temperature fuel cell tri-generation of...

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