Hydrogen Energy&Production

1Hilde Venvik, Institutt for kjemisk prosessteknologi.

Norges teknisk-naturvitenskapelige universitet

TKP4515 KEM Fall 2012Katalyse i energi og miljsammenhengHydrogen energy & production

2Why hydrogen?H2 + O2 = H2O H = - 285 kJ/mol

1. ENVIRONMENT: Emission = water Local, i.e. no NOx/SOx (but NOx in HT (flame) hydrogen combustion!) Global (but CO2 emissions depend on source and technology!)

2. Energy supply a possible energy carrier along with electricity

when fossil energy runs out flexible production from renewable and fossil energy sources flexible use can be converted into (electrical) energy i

In fuel cells ( not limited by the Carnot cycle) high efficiency By combustion (engines, turbines, catalytic)

easier storage than electricity (but)

Hilde Venvik, Institutt for kjemisk prosessteknologi.

3What is a fuel cell?E < 1.23 V

Helge Weydahl: Unitised regenerative fuel cells - opportunities and obstacles

Pleaseconsult fuelcell lecturefor details!

4Hydrogen is an energy carriernot an energy source!H2 can not be found in nature (on earth)

and must be produced from a hydrogen containing compound using energy

Water using external energy

Fossil hydrocarbons (natural gas, oil, coal) Biomass and waste

Hilde Venvik, Institutt for kjemisk prosessteknologi.

5Use of hydrogen today? Ammonia production

(NH3) fertilizer Methanol production

(in 2:1 mixture with CO, i.e. synthesis gas)

Oil refineries,e.g. sulfur removal

Industrial chemicals production

Space fuelStatoils methanol production facility at Tjeldbergodden among the worlds largest (www.statoil.com)

6Some important propertiesAtomic mass (hydrogen): 1.008 Density, gas at STP: 0.0899 kg/m3

Density, gas at 200 bar: 18 kg/m3

Density, liquid at 20.3 K: 70.8 kg/m3

Boiling point: 20.28 KMolar mass: 0.002 kg/molLower heating value: 120 MJ/kg = 10.8 MJ/Nm3 = 241 kJ/molHigher heating value : 142 MJ/kg = 12.7 MJ/Nm3 = 285 kJ/mol

=> The hydrogen molecule (H2) is LIGHTWEIGHT, SMALL and COMBUSTIBLE

7Hydrogen and safety

The start of the fire which destroyed the dirigible LZ 129 "Hindenburg" in Lakehurst 1937 had nothing to do with the hydrogen gas of which great amounts were on board to provide buoyancy. The reasons were the chemical and electrical properties of the paint of the outer shell in connection with the particular meteorological conditions prevailing in Lakehurst on the day of the accident

Hindenburg accident 1937

Examined carefully by the Deutsche Wasserstoff Verband, who reached the following conclusion:

(http://www.dwv-info.de/pm/pe00hb.htm)

8Some relevant key numbers for hydrogen, natural gas and gasoline

Property Hydrogen Natural gas Gasoline

Lower heating value (MJ/kg) 120 50 44,5

Self ignition temperature (oC) 585 540 228-501

Flame temperature (oC) 2045 1875 2200

Ignition limit in air (vol %) 4-75 5.3-15 1.0-7.6

Minimum ignition energy (uJ) 20 290 240

Explosion limit in air (vol %) 18-59 6.3-13.5 1.1-3.3

Theoretical explosion energy (kg TNT/Nm3 gas) 2.02 7.03 44.22

Diffusion coefficient in air (cm2/s) 0.61 0.16 0.05

In addition: Invisible flame, high flame velocity, leakage and hydrogen brittleness of some (metallic) materials

Hydrogen and safety - 2

9 Hydrogen ascends limited explosion danger in open air Precautions have to be made in closed spaces (+ detectors) A comparison: Heavier gases such as propane and gasoline vapour will

accumulate by the ground with danger of explosion in open air

Industry og space programs have long used hydrogen Students handle hydrogen Everybody handles gasoline...

Hydrogen cannot be claimed to be more or less dangerous than other fuels, but the risks are different!

Hydrogen and safety - 3

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Consequences of the properties storage and distribution challenges

Options for the fuel/storage tank: Compressed hydrogen Liquid hydrogen (20 K) Chemically bound in a (liquid) energy-

containing compound Absorbed or adsorbed in a solid Choice depends on whether the

application is Stationary Mobile (as in car) Portable (as cell phone)

LH2 tank in hydrogen-fueled BMW (engine)

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Consequences of the properties storage and distribution options

Compressed gas Cost of compression Leakage Weight, size and solidity of

cylinder

Liquid hydrogen (20 K) Cost of cooling! Leakage and evaporation Insulation

Chemically bound Synthesis, e.g. methanol,

NaBH4, LiH Extraction/conversion to

hydrogen By-products, e.g. CO2 Regeneration, e.g. NaBO2

Solid storage materials Weight Kinetics Stability

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Metal hydrides

M + x/2 H2 MHx + Q

M: A2B, AB, AB2, AB5 (crystalline)Examples: Ti, Mg2Ni, FeTi

Typical energy densities: 3 kW/l 0.3 kW/kg

Critical issues Hydriding and dehydriding temperatures Hydriding and dehydriding kinetics

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Implikasjoner av egenskapeneLagring og distribusjon av hydrogen er en betydelig vitenskapelig og teknologisk utfordring!

Muligheter for bensintanken: Gass ved hyt trykk

kompresjonskostnader lekkasjer sylinderens vekt og soliditet

Flytende hydrogen (20 K) kjlekostnader! lekkasjer sylinderens isolasjon

Bundet i en (flytende) energiholdig forbindelse, f.eks. alkohol

Absorbert eller adsorbert i et fast stoff stoffets tyngde og stabilitet, samt responstid

Valget er avhengig av hvorvidt applikasjonen er stasjonr eller mobil/brbar, samt teknologisk utvikling

Lagertank for LH2 i hydrogendrevet BMW.

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Other solid storage materials

Different carbon structures are claimed to have high potential (up to 16 kW/kg during at one point)

Remains to be verified!

Carbon cones produced at IFE

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Consequences of the properties storage and distribution 3

A storage solution for H2 in automobiles and other mobile applications is the challenging scientific and technological issue

Methanol works as a hydrogen carrier, but is nolong-term solution because of the CO2 problem (unless derived from biomass)

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Consequences of the properties storage and distribution 4

Use of H2 as a fuel for automobiles requires a completely new distribution system,i.e. rebuild or replacement of todays petrol stations.

Hen-and-egg problem? Who is going to carry that cost?

Examples of early Norwegian contributors to follow

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The first hydrogen filling station in Norway at Forus, Stavanger

It is now possible to fill up with hydrogen at Statoil's service station at Forus near Stavanger. Chief executive Helge Lund and transport minister Liv Signe Navarsete were present at the inauguration today, 23 August 2006

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HYNOR Norwegian

hydrogen road www.hynor.no Stations at

Oslo Lier (Drammen) Porsgrunn Stavanger

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Map is not completelyupdated!

See website.

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Norwegian H2 stations 2012 Stavanger, opened 2006 (Statoil): Bottles.

Shut down ~2011 Porsgrunn, opened 2007 (Hydro/Ineos):

H2 as byproduct from prod. of Cl Drammen, opened 2009 (Lindum): Bottles

to be produced from biogas (2012) Oslo kern opened 2009 (HYNOR Oslo partners:

Bottles (from Porsgrunn) Oslo Forskningsparken (H2movesEU), opened 2011:

Electrolysis Lillestrm, opened 2012 (IFE): Under construction

Demonstration of Sun + electrolysis AND biogas (sorption enhanced SMR) AND metal hydride kompression

!Find hydrogen filling stations worldwide: http://www.netinform.net/H2/H2Stations/Default.aspx

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Vehicles in Norway 2012 Cars available:

> 10 Mercedes-Benz F-Cell B-Class ready in Oslo Think (Norwegian) hydrogen Fall 2011, a few Hyundai ix35 FCEV. 5 Van Hool A330 Fuel Cell buses for Oslo & Akershus spring 2012. Line 81A,

Vestbanen Greverud. Some problems with keeping the buses in operation repoted

A few other cars

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Hydrogen production

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Hydrogen from natural gas

Steam reforming (SR) of natural gas at T>600C:CH4 + H2O CO + 3 H2 H = 206 kJ/mol

+ followed by the water-gas shift reaction at 200-500C:CO + H2O CO2 + H2 H = - 41 kJ/mol

The most common and most economic method of hydrogen production (95% world wide)!

Other energy dense compounds containing C og H (og O), e.g. propane, gasoline og methanol may be used(NB! Methanol is synthesized from 2H2 + CO made by SR)

= synthesis gas/

ammonia technology!

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Synthesis gas - general schemes

Any C-containing feed can be used (also biomass, close to coal)

Reforming routes require desulfurization

WGS and/or CO2-removal used for adjustment of composition

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Syngas adjustment and purification (NH3) Depending on the process

receiving the syngas the composition is adjusted.

Water gas shift (WGS)CO + H2O = CO2 + H2

Fig 5.18

Equilibrium, slightly exothermic, can run both ways, different catalysts for high and low temperature

High T shift: 650 - 700 K, Fe/Cr, kinetics Low T shift: 470 -520 K, more active catalyst (Cu/Zn),

to equilibrium

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Hydrogen production from natural gas some alternative reactions

(Catalytic) partial oxidation of hydrocarbons/carbohydrates (here: methane)

CH4 + 1/2 O2 CO + 2 H2 (H = - 36 kJ/mol) O/C ratio must balance to avoid complete oxidation (combustion) and carbon formation

Fast reactions high throughput potential Calls for oxygen plant or N2 dilution of process and product

Not commercially implemented; safety issues, catalyst stability, ...

Autothermal reforming/oxidative steam reforming of hydrocarbons/carbohydrates (here: methane)

CH4 + x (O2 + 3.76 N2) + 2 (1-x) H2O CO2 + (4-2x)H2 + 3.76 x N2 Balanced mixture of input fuel, air and steam

(catalytic) partial oxidation/combustion reaction supplies heat to drive steam reforming reaction

Temperatures in the range 700-1000 C No external heat supply needed, internal temperature gradients

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Hydrogen fromsome suggestions

Steam reforming (ethanol example)C2H5OH + H2O 2 CO + 4 H2 (H = X kJ/mol)

(Catalytic) partial oxidation (propane example)C3H8 + 3/2 O2 3 CO + 4 H2 (H = - 226 kJ/mol)

Autothermal reforming/oxidative steam reformingCnHm + xO2 (+ 3.76 N2) + yH2O nCO2 + (m/2+y)H2 (+ 3.76 x N2) (+H2O)

Water gas shift (WGS), CO to H2CO + H2O CO2 + H2 (H = - 41 kJ/mol)

CrackingC3H8 3 C + 4 H2 (H = 105 kJ/mol)2 NH3 N2 + 3 H2 (H = 46 kJ/mol)

28Fuel Pro Con Natural gas/ Methane CH4

readily available single component

gaseous CO2 emissions high temperature conversion

Lower hydrocarbons, C3-C5

liquid at moderate pressure simple production easy distribution and storage uniform composition

CO2 emissions high temperature conversion

Gasoline liquid infrastructure exists

CO2 emissions high temperature conversion trace sulphur challenging catalysis reformulation coking

Diesel liquid infrastructure exists

CO2 emissions high temperature conversion sulphur low H/C ratio problems in evaporation process

Fischer-Tropsch fuels CnH2n+2

no sulphur uniform composition infrastructure exists

energy wasted in production high temperature conversion

Ammonia NH3 no CO2 available at some remote places

unreacted NH3 will poison the fuel cellcorrosive and poisonous distribution

Methanol CH3OH Ethanol C2H5OH

liquid low temperature conversion single component no NOx or sulphur can be made from biomass

CO2 emissions energy wasted in production problems in evaporation process corrosive and poisonous (MeOH) infrastructure modifications

Pros and cons of energy containing hydrogen carriersfossil, synthetic, bio-derived - onboard/local conversion

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And noble

Process Catalyst System Conditions Comments Steam Reforming Ni/Al2O3, Ru

(hydrotalcite, MgO) 600-1000 C

1 30 bar Catalytic POX Pt, Rh/Al2O3,

gauze or monolith 1000 C

More complex if to be used on heavy hydrocarbons to avoid carbon deposition.

Autothermal Reforming

As steam reforming (Ru/TiO2suggested)

> 1200 C 1000 C

Combustion Reforming reaction wall temperature gas temperature

WGS, HTS LTS

Fe3O4-Cr2O3 Cu/ZnO/Al2O3

300-500 C 180-250 C

Not sensitive to pressure. Cu-catalyst is temperature sensitive.

CH3OH + H2O/O2 CuO/ZnO/Al2O3 CuO/Cr2O3/Al2O3

150-300 C Low pressure H2O:MeOH 1.5

Exxon claim to reach 100% yield with a Zn-Ca/silica-alumina catalyst at 480 C.

C2H5OH + H2O/O2 Rh,Ni,Co/Al2O3,MgO, ZnO CeOx addition

400-800 C

NH3 Cracking Fe, Ir, W 1000 C CH4 Decomposition Ni,Fe,Pd,Rh,Ru,Co

Carbon > 500 C Metal gauze or supported on Al2O3 or SiO2.

CO Oxidation Pt/Al2O3 (PdOx/MnO2)

> 200 C 50-150 C

100% convertion of CO 20% H2 loss. MnOx-support gives higher activity at low temperatures.

CO Methanation Ni, Ru 250 C

Hydrogen production from hydrocarbons/oksygenatesMost common catalyst systems + conditionsRed circles = most important

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Primary and secondary hydrogen-containing fuels Primary = fossil or biomass.

Contains energy as derived. Secondary = synthesized.

For example methanol or ammonia, that were made from synthesis gas (CO+H2) or hydrogen in the first place

Biomass subjected to treatment, for example fermentation (and distillation) to ethanol may be viewed as somewhere in between

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CO cleanup

CO limitations given by conventional (Nafion) PEM fuel cells is < 10-20 ppm (advantages of this fuel cell is low T and high current density)

HT+LT WGS not sufficient (will reach ~1% CO)

Selective oxidation of CO to CO2:CO + O2 CO2 - consumes H2 (unselective oxidation)

Methanation (used for NH3 after CO2 separation)

CO + 3H2 CH4 + H2O - consumes H2 by CO2 methanation H2-selective membranes

difference in H2 partial pressure must be significant, or need for sweep (=inert dilution) on permeate side (?)

H2 retentate (=membrane feed side) loss

Use a different fuel cell (->fuel cell lecture)

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Biomass/biofuels are (in principle) CO2-neutral Conversion to H2 instead of direct use is not necessarily the choice In practice, production and transport of biofuels sometimes imply

CO2 emissions

Hydrogen represents a way to utilize fossil fuels with minimized CO2 emissions CO2 capture and storage consumes energy and increases costs Implies that hydrogen is produced and distributed from large

facilities

The CO2 issue

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Hydrogen from fossil fuels

Sleipner CO2-injection:CO2-injection in the Sleipner st oil fields is part of Statoils program to reduce and avoid CO2 emissions. (www.statoil.com)CO2-capture and storage is possible, but requires energy and investments Separation Compression TransportLarge capacity, safe storage

The CO2 issue

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According to the experts there is plenty of storage capacity for CO2 sequestration in a long-term perspective. Predictions are positive with respect to the stability of the storage,

i.e. that we can trust that the CO2 stays where we put it, but more research is needed to verify this.

See recent developments for new approaches to CO2 capture

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Hydrogen from biomass In principle CO2 neutral Biomass = more or less

uniform and treated agricultural or naturally grown feedstocks,.

Hydrogen production by Gasification Steam reforming/partial oxidation of

agricultural (by-) products Nature 418, 964 - 967 (29 August 2002); Hydrogen from catalytic reforming of biomass-derived hydrocarbons in liquid waterR. D. CORTRIGHT, R. R. DAVDA & J. A. DUMESIC

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Gasification

Reaction with oxygen/air and or water at high temperature (1000 C) to form syngas

Non-catalytic, thermal process Applies also to coal and waste Limited air feed to limit complete oxidation reactions

Formation of ash and tar

SOx, NOx, NH3, H2S by-products, depending of feedstock and process conditions Downstream clean-up (filtration, catalytic) may be required

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TKP4150 repetition 1:

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TKP4150 repetition 2:

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TKP4150 repetition 3: Chemistry: Brief overview

Cellulose example:, but similar reactions for other types of biomass

Overall thermochemistry depends on use of air/oxygen Aromatic structure in lignin maintained to some extent, as

phenolic type compounds (tar) Low severity: More pyrolysis type products High severity: More gas

Source: Huber et al., Chem.Rev 106(9), 4044 (2006)

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TKP4150 repetition 4: 3 principal gasifier designs:

Design determined by (solid) biomass feed options Differences in ease of upscaling, thermal efficiency, tar yield etc. Tar yield: Downdraft < Fluid bed < Updraft Downdraft has lower thermal efficiency A wide range of other designs possible

Source: Huber et al., Chem.Rev 106(9), 4044 (2006)

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Hydrogen from biomass

Figure 1 Reaction pathways for production of H2 by reactions of oxygenated hydrocarbons (e.g. glucose) with water. (Asterisk represents a surface metal site.)R. D. Cortright, R. R. Davda & J. A. Dumesic Nature 418, 964 - 967 (29 August 2002)

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Production of hydrogen from water?

Straight-forward - just supply energy! Not competitive with steam reforming on basis ofcost nor energy consumption.

Elektrolysis is the common way. Hydro (Norsk Hydro Electrolyzers) has been world leading and is (Since 2011 NEL Hydrogen Notodden) still a global player.

Important in conjunction with new renewables (wind, solar), as a buffer technology. Hydrogen storage may be preferable to batteries

Produces very pure hydrogen (and O2)

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H2O -> H2 + O2 H=285 kJ mol-1

Electrolysis powered by Photovoltaics Windmills Hydropower Nuclear power

Or energy from Sunlight direct (photoelectrolysis, algae) Thermal sources - 3000K

(also in combination with electricity) Thermochemical cycles

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Hydrogen electrolysis of water

Alkaline (KOH) elektrolysis- traditional technology

- Norsk Hydro basis

PEM elektrolysis- hi- tech electrocatalysis

- world record at NTNU ~2003

PEM = proton exchange membrane

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Alkaline elektrolysis (KOH aquous solution)

A typical electrolyser system

25 % KOH, 80 oC High pH reduces the anodic (oxygen-evolution)

overpotential 1,7 1,9 V, 1 kA/m2, > 4.3 kWh/Nm3 H2 Ni-based catalysts (sulfur-activated) (+Mo, PM)

Porous electrode structures Electrodes will have to be replaced/reactivated after

2-3 years Significant ohmic losses in the diaphragma

(previously asbestos, nowsynthetic polymers)

Produced by Brown Boveri, NEL Hydrogen (NorskHydro)Lurgi, DeNora, Electrolyser Corp.Krebskosmo

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PEM Water electrolysisE > 1.23 V


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PEM Electrolysis reactions


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PEM Electrocatalysts for

O2 evolution reaction IrO2 [1] IrO2 w/ SnO2 [2, 3] IrO2 w/ Ta2O5 and RuO2 [3]

rate determining

[1] E. Rasten, G. Hagen, R. Tunold, Electrochim. Acta 48 (2003) 3945-3952

[2] A. Marshall, B. Brresen, G. Hagen, M. Tsypkin, R. Tunold, Electrochim. Acta 51 (2006) 3161-3167

[3] A. Marshall, B. Brresen, G. Hagen, M. Tsypkin, R. Tunold, Energy, In Press


H2 evolution reaction Pt

straight forward

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PEM Electrocatalysis IrO2

[1] E. Rasten, G. Hagen, R. Tunold, Electrochim. Acta 48 (2003) 3945-3952


Cell voltage as a function of current density, measured at 80 C

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PEM Electrocatalysis IrxSn1xO2



Voltage of PEM water electrolysis cell at 80 C.

Sn addition: Proposed to increase catalyst

stability. Reduces performance

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PEM Electrocatalysis Ir-Ru-Ta-O2



Polarisation curve of PEM water electrolysis cell at 80 C

The best result was obtained with an Ir0.6Ru0.4O2 anode and 20 wt% Pt/C cathode, with a cell voltage of 1.567 V at 1 A cm2 and 80 C when using Nafion 115 as the electrolyte membrane. This equates to a cell efficiency of 94.4% (H) and an energy consumption of 3.75 kW h Nm3H2 at 1 A cm2.

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(Photo: Pl Otto Eide)

2004: The Utsira Wind hydrogen demo project

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2010:Project

stopped

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Hydrogen production by photocatalysis The holy grail of hydrogen production:

Direct photocatalytic splitting of water to H2 and O2by visible light.

Photocatalysis (IUPAC): catalytic reaction involving the absorption of light.

Semi-conducting materials,such as TiO2

Challenges Wavelengths/bandgap separation and compression efficiency and cost Area

A-

A

D

D+

h Eg

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+

cb

vb

SC

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Importance of catalysis in fuel -> H2 -> electricity

Catalyticburner Reformer

Gascleanup

Water tank

Fueltank

Converter

Electricengine

Air H2

+

-

H2, CO, CO2 ,(H2O) H2, H2O

Air

Anode

PEMFC

Cathode

AC

Evap2Evap1

H H

Watercondensation

CO2, N2,(H2O)

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Catalytic combustion of H2- and its related exhaust

Heat generation for evaporation and endothermic reactions.

Anode exhaust clean-up (unconverted CO or H2 after FC anode).

H2 + O2 H2OCO + O2 CO2 fuel + O2 CO2 + H2O

Emissions will be H2 and CO2

Pd-, Pt-based catalysts

(high temperatures, stability issues)

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Some recent concepts- see extracurricular material Hydrogen production w/CO2 capture: Sorption

enhanced steam reforming Microstructured/short contact time reactors for partial

oxidation (high throughput/small scale) Membranes for hydrogen (CO2) separation

(catalytic membrane reactors) Membranes for oxygen (CO2) separation

(catalytic membrane reactors)

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Hydrogen energy & production summary H2 storage/distribution is the largest challenge H2 can be produced from a wide variety of

sources/carriers in large or smaller scale From natural gas is the cheapest and most efficient in large scale From fossil fuels w/CO2 capture (in large scale) From biomass through gasification or organic-catalytic routes High throughput/compact concepts for small scale From water using electricity of light

Electrolysis has seen significant advancement Photocatalysis is the holy grail

H2 use: Importance of fuel cell technology development High efficiency, low emission potential Cost and durability challenges

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Only the future can tellbut access to H2 enables

Good luck!

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Jacob A. Moulijn, Michiel Makkee, Annelies van Diepen, Chemical Process Technology, Wiley 2001 (ISBN: 978-0-471-63062-3)

Chapters 5.1, 5.2, (5.3), 5.4

I. Chorkendorff, J. W. Niemantsverdriet Concepts of Modern Catalysis and Kinetics, 2nd, Completely Revised and Enlarged Edition, Wiley 2007 (ISBN: 978-3-527-31672-4)

Chapters 8.2, 8.4 and 8.7

George W. Huber, Sara Iborra, and Avelino Corma, Synthesis of Transportation Fuels from Biomass: Chemistry, Catalysts, and Engineering, Chem. Rev. 2006, 106, 4044-4098

Lecture by Prof Svein Sunde, Dept. of Materials Technology, NTNU on electrolysis

+ ppt on some recent concepts

Suggested literature

Hydrogen Energy&Production

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