Fermeglia_H2Age

Transcript

Fermeglia_H2Age

Tomorrow’s Energy
Sexten, venerdì 29 giugno 2012
The end of the oil age?
A Transition to Hydrogen?
Maurizio Fermeglia – University of Trieste
Department of Engineering and Architecture
[email protected]
www.mose.units.it
Agenda
Hydrogen Era



Motivation: reduce emissions
Efficiency of energy transformation
Why Hydrogen?
Production and distribution of hydrogen



Sources
Production processes
Distribution
Hydrogen utilization



Fuel cells: fundamentals
Fuel cells for vehicles
Fuel cells for power generation
Conclusions
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Sexten, Friday, June 29, 2012- slide 2
1
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Does history repeat? transportation development
Colonel Edwin Drake drilled the first successful oil well in
Pennsylvania in 1859
In 1900 there were 8000 registered vehicles – mainly electric
vehicles
Steam and gasoline also competed for man’s quest for mobility
With the construction of a fuel network, which took a decade to
cross the US, gasoline had won and by 1920 there were
23,000,000 vehicles in the world!
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"The Stone Age didn't end
because they ran out of stones;
the Oil Age won't end because we
run out of oil.“
Don Huberts, Shell Hydrogen
2
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The green house effect…
2010: 380ppm
1900: 280ppm
CO2
CH4
N2O
CO2
CH4
N2O
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3
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Energy utilization
in 2009
Cars production in the
world (by year)
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Significant progress has been made in reducing local emissions
and the focus is now shifting to Greenhouse Gases
Emissions, % of 1995 level
140
120
CO
100
NOx
PM-diesel
80
VOC
60
Benzene
40
SO2
20
CO2
0
1985
1990
1995
2000
2005
2010
2015
Source : European Commission
Future challenge: Reduce CO2 while
maintaining low regulated emissions
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Changes to transport fuels are required to
meet sustainability challenges
Need to balance the requirements of affordable mobility while
reducing local and global environmental impacts



Cleaner Hydrocarbon Fuels enable more fuel efficient/low emission engine
technology.
Renewable Biofuels - e.g. ethanol and vegetable oil esters
Radical new technologies - e.g. Fuel cells & Hydrogen
Alternatives need to meet economic and social sustainability
criteria as well as contributing to environmental objectives.
Need to understand the challenge of consumer acceptance.
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Well-to-Wheel Greenhouse Gases - US Study
g CO2/mile
800
Petroleum
Natural Gas
Renewable/
Electricity
700
600
500
Better
400
300
200
100
G
Fu
D
as
o
lin
e
G
as
o
lin
e
IC
ie
se E
l
el
IC
C
N
el E
ap Die
l
s
H
ht
ha el IC EV
Fu
E
H
el
EV
C
FT ell
H
Di
EV
es
el
FT
IC
Na
E
C
N
ph
G
IC
Li tha
M
FC E
et qui
d
ha
H
E
no H2
FC V
lF
G
u
H
as
e
EV
eo l C
us ell
H2 HE
El
FC V
ec
ro
HE
ly
si
V
EEt
s
85
G
ha
H
I
C
no
2
FC E
lF
ue
H
l C EV
el
lH
EV
0
ICE: internal combustion engine
FT: Fisher Tropsch diesel
HEV: hybrid electric vehicle
GTL: gas to liquid fuel
CNG: compressed natural gas
E-85: 85% ethanol and 15% gasoline
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Hydrogen Economy........ a compelling vision
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The Hydrogen age:
the transition is uncertain...
THE TRANSITION IS
UNCERTAIN
THE PAST
Internal Combustion Engine
THE FUTURE
Product Performance
led to the Oil Age
The Fuel Cell can lead to
the Hydrogen Age
Time
Coal
1.5 : 1
Oil
1 :
2
Gas
1:
Hydrogen
4
0:
1
Underlying Decarbonisation
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Hydrogen is not prohibitively
expensive to get started today.
Relative Costs of Energy
(Hydrogen from Natural Gas)
Hydrogen Production Method
Cost ($/GJ)
$9,00
Central Production
$8,00
5-8
Coal
9-12
Electrolysis of Water
20
Gasified Biomass
8-13
$7,00
US Dollar per GJ
Natural Gas
Distributed Production
Onsite
$6,00
$5,00
$4,00
$3,00
$2,00
Natural Gas
8-15
Electrolysis (hydroelectric)
10-20
Electrolysis (wind)
20-40
Electrolysis (solar/thermal)
40-60
Electrolysis (photovoltaic)
50-100
$1,00
$0,00
Coal
Oil
Gas
(Sources: British Petroleum, Hoffmann, Ogden, and
Bossel/Eliasson.)
Hydrogen
With Gas priced at $3/MBTU
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Technology efficiencies
Biomass
1
Geothermal
8
Photovoltaic
10
Wind
25
Nuclear
33
Gas turbine
38
Coal
43
Fuel cell
50*
Gas combined cycle
58*
Hybrid fuel cell
66*
Hydro
80
0
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(*) DER
efficiencies
improve with
heat recovery
20
40
60
80
100
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The next 10 years will see a wider range of technologies
and fuel types, especially in the developed world
% of New cars
LPG/CNG
100
90
Diesel (inc Bio-diesel/GTL)
80
Compression
ignition engines
70
60
50
40
Hybrid
Gasoline (inc Ethanol)
30
20
10
Spark
ignition
Naphtha/Methanol
Hydrogen
Fuel cell
0
2000
2010
2020
One possible view of the future - not a forecast
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Timeline for Hydrogen Economy
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The Power of Innovation
Heavier-than-air flying machines are impossible,...

Lord Kelvin, President Royal Society, 1895
I think that there is a world market for maybe five computers

Thomas Watson, chairman of IBM, 1943
Computers in the future may weigh no more than 1.5 tons

Popular mechanics, 1949
There is no reason anyone would want a computer in their
home

Ken Olson, President, Chairman, and founder of Digital Equipment Corp.,
1977
64K ought to be enough for anybody

Bill Gates, 1981
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Time Taken to achieve 25% access in the US
The Original Gasoline Automobile
Electricity
The Microwave
The PC
The Web
Facebook …….
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> 55 years
c. 40 years
18 to 20 years
15 years
7 years
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Congressional Record 1875
A new source of power…called gasoline has been produced by a Boston
engineer. Instead of burning the fuel under a boiler, it is exploded inside of
the cylinder of an engine….
The dangers are obvious. Stores of gasoline in the hands of people interested
primarily in profit would constitute a fire and explosive hazard of the first
rank. Horseless carriages propelled by gasoline might attain speeds of 14, or
even 20 miles per hour. The menace to our people of this type hurdling through
our streets and along our roads and poisoning the atmosphere would call for
prompt legislative action even if the military and economic implications were not
so overwhelming ….
The cost of producing [gasoline] is far beyond the capacity of private
industry…
In addition the development of this new power may displace the use of horses,
which would wreck our agriculture.
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So Why Hydrogen?
Hydrogen Combustion:

H2 + ½ O2  H2O H= -57.8 kcal/mole
H2 is an energy carrier, is converted to water which has
minimal environmental impact.
H2 is a non-polluting fuel for transportation vehicles and power
production
Currently road vehicles emit about the same quantity of CO2 as
power production in developed economies.
H2 can be produced from fossil fuels with CO2 capture and
storage or from renewables
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In the long run, hydrogen has the potential to be
the ultimate fuel
Hydrogen
120
110
Higher Energy content
100
90
Low Heating
Value in MJ/kg
80
“Real Useable
Heat in the
Engine”
60
70
Propane
C2H6
Butane
50
CH4
40
30
RME
Gasoline / Diesel
Cleaner combustion
Coal
DME
Ethanol
Methanol
20
10
0
[H] in %w
0
10
20
30
40
50
60
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70
80
90 100
Agenda
Hydrogen Era



Why Hydrogen?



Sources
Distribution



Conclusions
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CO2 Capture and Storage:
Hydrogen Production from Fossil Fuels
H2 production from fossil fuels will predominate
H2 for transportation fuel only makes sense if CO2 is captured
and stored
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Production of Hydrogen
Options
Method
Photolysis
Characteristics
catalytic-water splitting
Electrolysis
Power for electrolyser
water
ambient  high temperature
ambient  high pressure
Thermal splitting
water
high temperature
Fossil fuel Conversion
Heat, water, oxygen, catalytic
Far Future
Non fossil fuel alternatives based on
sunlight, renewables and nuclear
Present
Fossil fuels
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Renewable Hydrogen Production via
Electrolysis
Typical 2 MW Turbine
gives 100 tonnes/year
Hydrogen
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Production of Hydrogen: Reactions
Reforming With Steam - Catalytic
Natural gas and light hydrocarbons
Partial Oxidation - Non Catalytic
Any hydrocarbon or carbonaceous
feedstock
Thermal Decomposition
Only limited application as co-product in
carbon black manufacture
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CH4 + H2O  CO + 3H2
CO + H2O  H2 + CO2
C + ½O2  CO
CO + H2O  CO2 + H2
CH4  2H2 + C
+ H
- H
- H
- H
+H
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Production of Hydrogen: Process Characteristics
50,000 Nm3/hr
Steam Natural
Gas Reformer
Open Systems


External heating of a
catalytic reactor
Combustion products
vented to atmosphere
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Production of Hydrogen: Process Characteristics
Closed Systems


Pressurised reactors with heat supplied by direct oxidation with oxygen
No venting of combustion products
Natural Gas
Natural Gas
Oxygen
Partial Oxidation
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Oxygen
POX
Steam
Catalyst
Autothermal Reformer
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Worldwide Market Scenario in 2020
Transit Buses*

130,000-150,000 buses in service
Light Duty Vehicles*

17- 80 million vehicles in service
Hydrogen Required†

2.5 - 9 million tonnes per year
Current Largest Merchant H2 Plant

100,000 tonne/year
HUGE INFRASTRUCTURE TO BE BUILT
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Timeline for Hydrogen: Production Technologies
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Agenda
Hydrogen Era



Why Hydrogen?



Sources
Distribution



Conclusions
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Fuel cells: Power station & Automotive
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A fuel cell system
For top efficiency, you must use the heat!
Ultimately, hydrogen is needed!
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Electricity
Electrical current is the flow of electrons.
Need a source of electrons, a medium in which they can flow,
and a driving force.
Electrons Produced
Anode (-)
low E (V)
ee-
e-
E (V)
e-
conductor
Source of Electrons
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Electrons consumed
Cathode (+)
high E (V)
Sink for Electrons
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Oxidation and Reduction
Electrons are produced and consumed in oxidation and
reduction reactions.
Oxidation is loss (OIL)of electrons:



Fe  Fe2+ + 2eCa  Ca2+ + 2eNa  Na+ + e-
Fe  Fe3+ + 3eMg  Mg2+ + 2eH2  2H+ + 2e-
Reduction is gain (RIG) of electrons:



Cl2 + 2e-  2ClAg+ + e-  Ag
Ni3+ + e-  Ni2+
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Br2 + 2e-  2BrMn5+ + 3e-  Mn2+
O2 + 4e-  2 O2-
Half Reactions
Individual oxidation and reduction reactions are half reactions.
Must occur together to make an overall oxidation-reduction
reaction.
EX.
Mg (s)  Mg2+ + 2 e+ Cl2 (g) + 2 e-  2 ClMg (s) + Cl2 (g)  MgCl2 (s)
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OXIDATION
REDUCTION
OVERALL
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Reduction Potential
Each half-reaction has a characteristic reduction potential (E).

E is a relative measure of energy released by adding electrons.
EXAMPLE.
2H+ + 2e-  H2 (g)
E = 0.000 V
+
4H + O2 (g) + 4e  2H2O
E = +1.23 V
Positive E indicates that energy is obtained by adding electrons.


G = - n F E°
F= Faraday’s constant; n= n. of electrons
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Overall Reaction
For hydrogen and oxygen:
OX: 2H2 (g)  4H+ + 4e-
E = 0.00 V
RED: O2 (g) + 4H+ + 4e-  2H2O(g)
E = 1.23 V
TOTAL:
2H2 + O2  2H2O
E = +1.23 V
Large, positive E  more energy
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Fuel Cells
Fuel and oxidant react to produce electricity directly without combustion.



Oxidation: 2 H2 (g)  4 H+ + 4 eReduction: O2 (g) + 4 H+ + 4 e-  2 H2O
Overall: 2 H2 + O2  2 H2O, E = +1.23 V
How does this happen without combustion occurring or H2 and O2 coming
into contact with each other?
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Combustion vs. Electron Transfer
Chemical reactions are the same!
Reaction rate and types of energy produced are different.
Reaction
Chemical
Products
Energy Produced
Rate
Combustion
CO2, H2O
Noise, heat, light
Fast
Electron Transfer
CO2, H2O
Electrical, some
heat
Slow
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Basic Operation of Fuel Cells
Fuel and oxidant are
separated.
Ions conducted through
electrolyte, electrons carried
through external circuit
Electrodes are catalysts that
facilitate the reactions
Anode : H 2 
 2H   2e 
Cathode : O 2  4H   4e  
 2H 2 O
Overall : 2H 2  O 2 
 2H 2 O
H2 and O2 never come into contact, only H+ and O2-!!
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Fuel Cell
Anode
Cathode
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Basic Electrochemistry for Fuel Cell
Basic Electrochemistry for Fuel Cell



Chemical Energy = Electrical Energy – Energy losses
Grxn = Current*Voltage*time – Energy losses
Grxn = V*(charge passed) – Energy losses
 As current  0 the energy losses 0



Grxn = V*(charge passed)
= V*(moles reacted)*(electrons transferred per molecule)*(coulombs per mole)
= V*n*F
For H2+O2 H20 G=240 kJ/mol H2, n=2 electrons/H2
V=240 kJ/mol / (2*96485 coulomb/mol) = 1.23 Volt
Advantages of Fuel cells

Fuel cells can be made very tiny.

Power the product of current (I) and potential difference (V)
 m, nm instead of mm, cm.
 P = I*V so  I and/or  V means  P.
 Higher fuel and oxidant flows increase I.
 Stacking of fuel cells increases V.
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Ideal (Nernst) potential as a function of T
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Basic Principles
Thermodynamics
G = - n F V
1.4
Activation Polarization
1.2
Voltage (V)
1
Theoretical Efficiency
 = G/ H ~ 0.83
0.8
0.6
0.4
Actual Efficiency (best
conditions) ~ 0.5
0.2
Mass
Transport
Limited
Ohmic Polarization
0
0
1
2
3
4
5
6
Current Density (A/cm2)
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Energy Losses
Activation Polarization
eA node
Cathode

P olymer
Electrolyte
H
2
7
1
4
11
H+
5
6
H+
porous
carbon
5
O2
H O
Ohmic Polarization
2

7
C arbon Fiber
Sheet
5
Pt
H
8
2H
O2
a
2
a
2Oa
9
3
H
2e- + O a
e- + H+
2H+ +O=
electro-migrat ion
10
O
Resistive losses of proton
transport through the
electrolyte
Mass Transfer Polarization

2
Energy barrier associated
with catalytic reactions at the
electrodes
Limit of getting the reactants
to the active catalyst surface
=
H O
2
H O
2
dif f usion
H O
2
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Voltage – current relationships
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Fuel Cell Types & Efficiencies
Fuel Cell Type
Operating
Temp. (°C)
Projected
Efficiency
Suitable
Applications
Alkaline (AFC)
80-100
60%
Space, Automotive
Molten Carbonate (MCFC)
600-650
45-60%
Large Stationary
Phosphoric Acid
200-220
40-45%
Large Stationary
Proton Exchange
Membrane (PEMFC)
70-80
35-45%
Small Stationary,
Automotive, Portable
Solid Oxide (SOFC)
800-1000
50-65%
Stationary, Automotive
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Alkaline Fuel Cell
Electrolyte:
85%wt KOH @ ~250°C
35 to 50%wt KOH @ <120°C
Catalyst: Ni, Ag, metal oxides,
spinels, and noble metals
Advantages:


Excellent Performance on H2 and O2
compared to other due to its active
O2 electrode kinetics
flexibility to use wide range of
electro-catalyst
Disadvantages:



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Sensitive to CO2 and CO
Needs pure H2
CO2 must be removed if ambient air
is used
Molten Carbonate Fuel Cell
Electrolyte: combination of alkali
carbonates retained in a ceramic matrix
of LiAlO2
Electrodes: Nickel & nickel oxide
Advantages:
 No expensive electro-catalysts needed
 both CO & certain hydrocarbon can be
use as fuel
 High temperature waste heat allows
use of bottoming cycle to increase
system efficiency
Disadvantages:
 Very corrosive electrolyte
 Material problems, affecting
mechanical stability and stack life.
 Large size & weight and slow start-up
times
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Phosphoric Acid Fuel Cell
Electrolyte: 100% Phosphoric Acid
retained by silicon carbide
Catalyst: Platinum
Electrodes: Porous Carbon
Advantages:
 Less Sensitive to CO, ~1% tolerance
 Relatively low temperature to use
common construction materials
 Waste heat can be used in
cogeneration/bottoming cycle
application
Disadvantages:
 Cathode-side oxygen reduction is
slower than AFC
 Use of expensive materials in the stack
(especially the graphite separator
plates) due to corrosive phosphoric
acid.
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Proton Exchange Membrane
Electrolyte: Ion Exchange Membrane
(fluorinated sulfonic acid polymer or similar)
Electrodes: Porous Carbon
Catalyst: Platinum
Advantages:
 Solid electrolyte resistant to gas crossover
 Rapid start-up
 Absence of corrosive constituents, exotic
materials are not required.
 High current densities of over 2kW/l & 2
W/cm2
Disadvantages:
 Difficult to use rejected heat.
 Must balance sufficient hydration of
electrolyte against flooding
 Higher catalyst loading (platinum)
 Anode is easily poisoned by CO
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Solid Oxide Fuel Cell
Electrolyte: Solid, non porous metal oxide
Y2O3-stabilized ZrO2.
Advantage:
 Solid electrolyte enable casting of the cell
in various shapes, such as tubular, planar,
or monolithic
 Solid ceramic construction alleviates any
corrosion problems
 Fast kinetics and CO is directly usable as
fuel
 No requirement for CO2 at the cathode
and resistant to sulfur.
 Modest cost materials
 High temperature allows use of waste
heat for cogeneration or bottoming cycle
and internal reforming of fuel.
Disadvantage:
 Thermal expansion mismatches among
materials and sealing between cells is
difficult in the flat plate configurations.
 Slow startup
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Types of fuel cells
Fuel used



Hydrogen:
Methanol:
Propane:
2 H2 (g) + O2 (g)
 2 H2O (g)
CH3OH (g) + O2 (g)
 CO2 (g) + H2O (g)
C3H8 (g) + 5 O2 (g)
 3 CO2 (g) + 4 H2O (g)
Configuration
Planar Configuration
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Tubular Configuration
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The Process
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Process: simplified version
(external reformer)
Natural
Gas
H2
Cleanup
Burner
Water
Anode
Reformer
Air
Cleanup
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Exhaust
Gas
Cathode
Internal reforming
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Energy from waste (Ansaldo)
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Biomass gassification and MCFC
Biomass
Pre treatment
Gasification
Gas
Clean-up
Reforming
Burner
Water
Evaporator
An.
Cath.
Air/Oxygen
Pre heating
Co generation
Turbine
Compr
Air
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Il processo nuovo
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Agenda
Hydrogen Era



Why Hydrogen?



Sources
Distribution



Conclusions
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The Alternative to a Hydrogen Future
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Modeling fuel cells
Steady state and dynamic modeling of fuel cells:
Molten carbonate Fuel Cell MCFC
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Modeling MCFC
Goals

Develop a dynamic model for the MCFC





Bi dimensional geometry cross-flow
Density and chemical reaction distributed
Considers conduction and convention
Solids are considered with their physical properties
Anode and Cathode are independent

Check steady state and dynamic cell behavior

Develop a steady state simulation of the process
 Sensitivity analysis
 Simplified model for the cell (based on the rigorous model)
 Sensitivity analysis
Topics covered



The cell model
The Results of the cell steady state and dynamic simulation
The plant model and the sensitivity analysis
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MCFC simulation:
model equations development
The cell: a Molten carbonate Fuel Cell – second generation
Assumptions of the model
Flow and reaction scheme
Equations of change
Electrochemical equations
Balances and boundary conditions at cathode
Balances and boundary conditions at anode
Balances and boundary conditions at electrolyte
Physical properties


From Aspentech™ Data base (except for Nu)
From Literature correlations (electrolytic properties)
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Assumptions and Input data (1)
Anode feed: vectors of stoichiometric coefficients for the
electrochemical and water gas shift reaction
Cathode feed: vector of stoichiometric coefficients
Electrolyte composition: potassium, sodium and lithium
carbonates are considered.
Ideal gases: mixture effects on densities are ignored; the ideal
gas law is assumed and the activities are assumed to be equal
to partial pressures.
Adiabatic system: no heat exchanged perpendicularly to the
overall flow; electrolytes do not exchange heat with the
borders.
Reaction rate: full Butler-Volmer equation is applied (quasi
equilibrium reaction and negligible ion conduction resistance of
the electrolyte)
Cudicio A., Fermeglia M., Pricl S., J. Power Sources, submitted (2005)
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Flow and reaction scheme
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Assumptions (2)
Thick channel distribution on the cell plane
Plug flow: parabolic profiles on different
channels are approximated by a velocity
on a single direction
(vx for cathode and vy for anode).
Perfect mixing: negligible diffusion flow.
Bi dimensional model:


velocities and their derivatives along the z-axis are neglected
characteristic dimension for calculating the fluxes along the z-axis is the geometric mean of
the bi-dimensional extensions
Equal current distribution at the electrodes, due their negligible thickness.
Nitrogen effects: nitrogen oxides at the cathode and ammonia at the anode
are ignored.
Nusselt number is function of Prandtl number, Reynolds number and
geometrical factor: Brinkman and Grashof numbers are neglected.
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Equations of change: application to anode
Example: anode
D
     v   r
Dt
Dv

     P
Dt
 cv
DT
 P 
    q   T 
    v    : v   S
Dt
 T  V
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35
Tomorrow’s Energy
Electrochemistry equations
Nerst equation
Polarization equation
  Re   A  C
RT a a
V0  E0 
ln
nF a a
Butler – Volmer equation

i0  i0 i00 , PO2 , PCO2
C



V  V0  i
1   nF i 

  nFi RT
RT
i  i0  e
e



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Degrees of freedom analysis
• Method Of LINES
• Variable Step Implicit EULER
• Fast NEWTON
Fermeglia M., Cudicio A., Desimon G., Longo G, Pricl S. Chem. Eng. Trans. 4: 391 (2004)
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36
Tomorrow’s Energy
Aspen Custom Modeler™
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Base Case and Sensitivity analysis
BASE CASE
v(0.27,1.7)
0.33
1.52
870.0
860.0
3.500
3.500
1.500
0.27
1.70
T(840,830)
P(2.5,3.5)
840.0
830.0
3.380
3.378
2.500
3.500
i(1.7)
Input variables
v(x,0) – m/s
v(0,Y) – m/s
T(x,0) - K
T(0,y) - K
P(x,0) - bar
P(0,y) - bar
i
- kA/m2
1.700
Output Variables
U H2 - %
75.000
82.279
75.132
89.450
80.746
U O2 - %
30.000
28.041
30.955
30.812
34.780
Ta out - K
930.3
930.2
909.5
936.1
946.3
Tc out - K
952.9
954.1
932.4
963.6
974.4
Te av. - K
938.9
940.8
919.7
948.5
957.8
i00
- kA/m2
0.024
0.025
0.015
0.029
0.027
V av. - V
1.092
1.081
1.069
1.083
1.076
W av. - kW/m2 1.636
1.620
1.599
1.625
1.827
Fermeglia M, Cudicio A., DeSimon G., Longo G., Pricl S., Fuel cells, 5:66-79 (2005)
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37
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Base case distributions
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Results of dynamic open-loop simulation
Input: Pressure perturbation


Anode pressure perturbation
Step input (1 bar)
Output: Temperature profile at
anode



Inverse response
Fast phenomena (P prop T)
Slow response (heat of reaction)
Output: Voltage distribution



Inverse response
Fast phenomena:
potential rises as V ~ ln(PA-1) ~
PA-1
Slow phenomena:
decrease of E0 with decreasing T
dominates
Tomorrow’s Energy
38
Tomorrow’s Energy
Dynamic Results: temperature effect
Temperature perturbation


Anode and Cathode
Semi - sinusoidal ramp (different time)
Fermeglia M, Cudicio A., DeSimon G., Longo G., Pricl S., Fuel cells, 5:66-79 (2005)
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The power generation process
Based on simplified model of MCFC
39
Tomorrow’s Energy
The Process
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Process: simplified version
(external reformer)
Natural
Gas
H2
Cleanup
Burner
Water
Anode
Reformer
Air
Cleanup
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Exhaust
Gas
Cathode
40
Tomorrow’s Energy
Internal reforming
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A conceptual diagram of 50 MW
MCFC power generation plant
Tomorrow’s Energy
41
Tomorrow’s Energy
Steady state process simulation
De Simon G., Parodi F., Fermeglia M., Taccani R., J. Power Sources, 115, 210, (2003)
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Steady State Process Simualtion: details
Electrochemical model
Modular Integrated Reformer
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42
Tomorrow’s Energy
Steady State process simulation
Fuel cells efficiency defined as the
ratio of electric power produced by
the stack and chemical power of
the fuel actually consumed
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Base Case & Sensitivity analysis
Base Case:
In accordance
with 500 kW
MCFC from
ANSALDO
Sensitivity
analysis on
H2O / CH4
Tomorrow’s Energy
43
Tomorrow’s Energy
Fuel cell module sensitivity analysis
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Process simulation sensitivity analysis
Air flow rate
sensitivity analysis
Pressure sensitivity
analysis
Tomorrow’s Energy
44
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Energy from biomass
MCFC based process
Energy from waste (Ansaldo)
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45
Tomorrow’s Energy
Biomass gassification and MCFC
Biomass
Pre treatment
Gasification
Gas
Clean-up
Reforming
Burner
Water
Evaporator
An.
Cath.
Air/Oxygen
Pre heating
Co generation
Turbine
Compr
Air
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Il processo nuovo
Tomorrow’s Energy
46
Tomorrow’s Energy
Biomass gassification
Literature
Gas
Steam
Oxidant
ULTIMATE
ANALYSIS
• Mole fraction
Gassification
• Temperature
Biomass
• Pressure
PROXIMATE
ANALYSIS
DATA FITTING
Model
Gas
Steam
Oxidant
Mole fraction
Gassification
Temperature
Model
Pressure
Biomass
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Simulation strategy
FLow rate of biomass
under investigation
Number of cells in the stack
Model Input
modified
Gassification
Model
•I
• Fule conversion
(CO + H2 75%)
• boundary conditions
• ...
original
•I
• n. of cells
• boundary
conditions
•...
N of cells
(different for different
biomasses)
Felxibility of the tool
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Tomorrow’s Energy
Different biomass investigated
Sugarcane bagasse (BG) : residue from sugar cane treatment
Switchgrass (SW)
Nut shells (NT): mix 20% nut shell, 40% hazel nut shell, 40%
wood
Proximate
analysis
bg
sw
nt
Ash
6,99
5,24
2,38
Volatile
Subst.
C residual
HHV (MJ/kg)
Ultimate
analysis
80,06
80,09
76,28
12,95
14,67
21,34
17,77
18,62
19,80
bg
sw
nt
C
46,46
47,73
48,51
H
5,4
5,56
5,65
N
0,18
0,67
0,77
S
0,06
0,01
0,01
Ash
8,5
5,24
3,07
O
39,36
40,68
41,98
Cl
0,04
0,11
0,01
Source: Gas Technology Institute, 2002
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Comparison of biomass feeds
for constant conversion in the cell
R =
( kg H 2 +kg co )
( kg biomassa )
out
biomass
bg
sw
nt
R
0,24
0,34
0,38
biomass
bg
sw
nt
Humidity
20 %
12 %
12,5 %
in
Type of
Biomass
Electrical
Efficiency
(%)
Cogeneration
Efficiency (%)
Biomass
Flow rate
Kg/h
Total
Electrical
Power kW
Gasifier
efficiency
%
Conversion
at anode
Bg
36.5
68.4
1900
2739
76.5
75%
Sw
40.3
69.1
1550
2841
82.2
75%
nt
40.2
69.9
1450
2802
84.5
75%
Tomorrow’s Energy
48
Tomorrow’s Energy
Summary - Conclusions
Environmental legislation will continue to tighten.
The next 3 decades will see a multitude of fuels and
technologies employed on a regional basis.
Automotive development will improve the efficiency of use
of remaining fossil fuels
The necessary technology for a viable H2 infrastructure of
production, distribution and storage already exists.
Hydrogen production from fossil fuels with CO2 capture and
storage is likely to provide the bulk of hydrogen required in
the next 30-50 years
R&D should concentrate on cost reduction for production,
transport and storage alternatives, and demonstration projects
Tomorrow’s Energy
The Alternative to a Hydrogen Future
Tomorrow’s Energy
49

Fermeglia_H2Age

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