Global Climate and Energy Project (GCEP)Stanford University, April 15-16, 2008y, p ,

Workshop on Carbon Management in Manufacturing Industries

C P d ti f SCo-Production of Syngas and Metals or Lime

Martin M. Halmann

Dept. Environmental Sciences & Energy Research,Weizmann Institute of Science, Rehovot, Israel

Outline

Several high-temperature endothermic chemical reactions are major contributors to the anthropogenic CO2are major contributors to the anthropogenic CO2

emissions:1. The reforming of natural gas to syngas and various g g y g

chemicals and fuel.2. The calcination of limestone to produce lime and

cement, CaCO3 = CaO + CO2.3. The production of metals from their ores,

a) Fe2O3 + 3C = 2Fe + 3COb) Al2O3 + 3C = 2Al + 3CO2 3

c) 2MgO-CaO + FeSi = 2Mg + Ca2SiO4 + Fe

Causes of CO2 EmissionsCauses of CO2 Emissions

CO2 emissions from these processes are due:2 p

1. Partly from the chemical reactions themselves.y2. Partly from fossil fuel combustion for process heat.

Considerable fuel savings and CO2 emission avoidance are expected by modifying these reactions.

The sequestration of CO2 is usually very expensive –unless its cost is offset by a profitable process – such as enhanced oil recovery.

Reforming by Combining -Tri) 1E d th i d E th i R tiEndothermic and Exothermic Reactions

The combination of heat releasing and heat absorbing reactions had been applieds ccessf ll to the catal tic reforming of nat ral gas to s ngassuccessfully to the catalytic reforming of natural gas to syngas

By simultaneously reacting natural gas with steam and with carbon dioxide,

CH4 + H2O = CO + 3H2 ΔH = 206 kJ/mol (1)

CH4 +CO2 = 2CO + 2H2 ΔH = 247 kJ/mol (2)

which are both strongly heat consuming reactions and also with oxygen by a heatwhich are both strongly heat consuming reactions, and also with oxygen by a heat releasing reaction,

CH4 + 1/2O2 = CO + 2H2 ΔH = -38 kJ/mol (3)

an overall thermo-neutral process of tri-reforming could be achieved, which (once started) does not require an input of external heat by combustion of fossil fuel.

Ashcroft et al, Nature, 352, 225,1991

Reforming for Rapid -TriH d P d iHydrogen Production

A mixture of CH4 – CO2 – H2O – O2

(60 : 10 : 10 : 20%)

Passed at 700oC over the 4-component catalyst

Ni Ce O Pt Rh (6 6 : 3 9 : 2 2 : 0 2 wt%)Ni – Ce2O3 – Pt – Rh (6.6 : 3.9 : 2.2 : 0.2 wt%)

supported on ceramic fibers,

resulted in 90% methane conversion

with a contact time of 5 ms and a

space-time yield of 12.2 kmol H2 L-1 h-1

The inclusion of O2 in the gas feed provided the heat

required for the reforming reactionsrequired for the reforming reactions

Inui, Appl. Organometal. Chem. 15, 87, 2001

reforming of power station -Triflue gases

Tri-reforming has been proposed for the utilization of the

t ti fl f d tipower station flue gases for syngas production

Using specific catalysts, the high-temperature reaction of the

flue gases with natural gas results in the combined

steam/CO reforming and partial oxidation of methanesteam/CO2 reforming and partial oxidation of methane.

Song and Pan, Catal. Today, 98, 463, 2004

Major Components of Flue GasesChunshan Song Chemical Innovation 31 21 2001Chunshan Song, Chemical Innovation, 31, 21, 2001

Gas-Fired Coal-Fired BoilersBoilers

8-10%12-14%CO2 %%2

18 20%8 10%H O 18-20%8-10%H2O

2-3%3-5%O2

67-72%72-77%N2

Tri-Reforming of Flue-Gas from Coal-or Gas-fired burnersor Gas fired burners

How to produce syngas suitable forHow to produce syngas suitable formethanol synthesis?

(1) Added air is necessary to achieve an( ) yoverall thermoneutral process.

(2) An excess of methane is necessary to(2) An excess of methane is necessary toobtain syngas useful for both hydrogenand ammonia synthesis.and ammonia synthesis.

Halmann and Steinfeld, Energy, 31, 3171, 2006

Conclusions on Trireforming of Flue Gases

(a) CO2 Consumed for Production of Syngas;(a) CO2 Consumed for Production of Syngas;(b) N2 Consumed for Production of Ammonia;(c) Decreased CO2 Emission by Tri-Reforming;(c) Decreased CO2 Emission by Tri-Reforming;(d) Increased CO2 Emission by Coal Gasification;(e) Fuel Saving particularly by Coal Gasification;(e) Fuel Saving, particularly by Coal Gasification;(f) Favorable Economics;But: For Significant CO Emission Mitigation by TriBut: For Significant CO2 Emission Mitigation by Tri-

Reforming - the World Proved Reserves of Natural Gas would be Insufficientwould be Insufficient.

Halmann and Steinfeld, Catal. Today, 115, 170, 2006

-Neutral Co-) Proposed Thermo2P d ti f Li d SProduction of Lime and Syngas

To Combine the Endothermal Decomposition of Limestone to Lime,p

CaCO3 -> CaO + CO2 ΔH298 = +178 kJ/mol

and the Endothermal CH4/CO2 Reforming,

CH4 + CO2 -> 2H2 + CO ΔH298 +247 kJ/mol

with the Exothermal Partial Oxidation of CH4

CH + 1/2O = CO + 2H ΔH 38 kJ/molCH4 + 1/2O2 = CO + 2H2 ΔH298 -38 kJ/mol

to achieve an Overall Thermo-neutral Reaction

Halmann, Steinfeld, Energy & Fuels, 17, 774 (2003)H l St i f ld E 31 1533 (2006)Halmann, Steinfeld, Energy, 31, 1533 (2006)

Equilibrium Composition vs. Temperature for Initial bar of1 K and 300 Mixture at

CaCO3 + 4CH4 + 2H2O + 8.7N2 + 2.3 O2

0 35

0 25

0.3

0.35

CH4

H2

0.2

0.25

Frac

tions CO2

COH2CO

0.1

0.15

Mol

e F

H2OCaCO3CaO

H2O

CaOCO2

0

0.05

700 900 1100 1300

CaO

CaCO3

700 900 1100 1300

Temperature, K

Emission Avoidance by 2Fuel Economy and COP d ti f Li d M th lC Production of Lime and Methanol-Co

Assume Thermochemical Equilibrium at 1100 K andAssume Thermochemical Equilibrium at 1100 K and 1 bar:

CaCO3 + 4CH4 + 2H2O + 8.68N2 + 2.32O2 = 3 4 2 2 2

CaO + 7.56H2 + 3.79CO + 2.44H2O + 1.21CO2 + 8.68N22

By Proposed Co-Production followed by Methanol Synthesis:

Fuel Saving by Co-Production = 29%CO E i i A id b C P d i 88%CO2 Emission Avoidance by Co-Production = 88%

-Emission Avoidance by Co2Calculated COP d i f Li d A i UProduction of Lime and Ammonia or Urea

Assume Thermochemical Equilibrium at 1100 K and 1 bar

CaCO3 + 4CH4 + 2H2O + 2.3O2 + 8.7N2 = CaO + 7.6H2 + 3.8CO + 2.4H2O + 1.2CO2 + 8.7N2

By Proposed Lime and Syngas Co-Production followed by W G Shif d A i S h iWater-Gas Shift and Ammonia Synthesis:

CO2 Emission Avoidance by NH3 Co-Production = 23%

If Ammonia is Converted to Urea: 2NH3 + CO2 = H2NCONH2 + H2O

CO2 Emission Avoidance by Urea Co-Production = 47%

Why Choose Ammonia as Preferred Product from Syngas?

Ammonia and urea essential as fertilizers in agriculture.Expected world demand exceeds world capacityExpected world demand exceeds world capacity.Ammonia production uses 3% of world energy

consumptionconsumption.Ammonia production would consume part of flue-gas

nitrogen.nitrogen.Ammonia could become important as a hydrogen

carrier for ammonia fuel cells.

Urea production consumes over 70% of CO2

generated from ammonia productiongenerated from ammonia production.

Production -Conclusions on Cof Li d Sof Lime and Syngas

1 S d C O P d ti i Si l R t1. Syngas and CaO Production in Single Reactor

2. Much Decreased CO2 Emission2

3. Fuel Saving by Thermo-Neutral Process

4. Attractive Economics

5 But: Requires further Experiments5. But: Requires further Experiments,

Particularly on the Reaction Kinetics

Reduction by 4O3) Solar Furnace Fe3MethaneMethane

At 1300 K and 1 atm, Fe3O4, fluidized in CH4, was 300 d , e3O4, u d ed C 4, w sconverted into Fe and syngas

Fe3O4 + 4CH4 = 3Fe + 8H2 + 4COFe3O4 + 4CH4 3Fe + 8H2 + 4CO ΔH = 978 kJ/mol

Steinfeld, Kuhn, and Karni, Energy, 18, 239 (1993)

Advantage: Process heat supplied by solar energy.

Drawback: For continuous processing requires a hybrid solar–fossil fuel energy supply.

Produced -Metals and Syngas CoReactions by Combining the Thermoneutralin

b CHR d i f M l idE d h i 4by CHReduction of Metal oxidesEndothermic2by O4of CHPartial OxidationExothermicwith the

ZnO + CH4 = Zn +CO+ 2H2 ΔH 298K = 315 kJ/mol

F O + 4CH 3F +4CO + 8H ΔH 976kJ/ lFe3O4 + 4CH4 = 3Fe +4CO + 8H2 ΔH 298K = 976kJ/mol

Fe2O3 + 3CH4 = 2Fe +3CO + 6H2 ΔH 298K = 717 kJ/mole2O3 3C 4 e 3CO 6 2 298K 7 7 J/ o

CH4 + 1/2O2 = CO + 2H2 ΔH 298K = - 36 kJ/mol

2002, 1069, 27Halmann, Frei, Steinfeld, Energy,

Thermoneutral Carbothermic Reduction of Fe OThermoneutral Carbothermic Reduction of Fe2O3

Thermochemical Equilibrium Composition vs. Temperature for the System:

Fe2O3+6.5C+2.55O2

5

6CO

2

3

4

Mol

es

FE(cryst)FeO(s)COFe

C(gr)

0

1

2M CO2C(gr)

Fe

CO2

FeO

-1900 1100 1300 1500

Temperature, K

Equilibrium Composition for the System )5.3: 9 .4: 1 (molar ratio 2O-4CH-3O2Fe )(2432

7.0

8.0

7

8

H2(g))

H2OH2O(g)on

H2

4 0

5.0

6.0

4

5

6 CO(g)

C CH4(g)FeCO( )um

Com

posi

tiokm

ol H2O

2.0

3.0

4.0

2

3

4 CO(g)2

FeO Fe3O4

Fe2O3

Equ

ilibr

iu k

Fe

CO

FeO

0.0

1.0

0

1

400 600 800 1000 1200 1400 1600 1800 2000

Temp. K

Thermogravimetric experiments with ~100 mg Fe2O3 under 3.6% O2 in Argon. After equilibration at 1400oK, 5.1% CH4 was introduced.

Halmann, Frei and Steinfeld, Energy, 27, 1069, 2002120

4

4.5

100

3.5

MassCH4O2H2

H2

60

80

Mas

s %

2.5

3

Volume %

CO2CO

Mass

CO

40

Ma

1.5

2

Vo

CH4

20

0 5

1

CO2

O

00 10 20 30 40 50 60 70

Time / min

0

0.5O2

Emission Avoidance and Fuel Saving by 2COProduction of Iron and Methanol-Co Production of Iron and MethanolCo

Thermochemical Equilibrium at 1400K, 1 bar:

Fe2O3 + 6.5C + 2.6O2 = 2Fe + 4.9CO + 1.6CO2

followed by partial water gas shift of CO to Hfollowed by partial water-gas shift of CO to H2,

and methanol synthesis.

By Proposed Co-Production:

CO2 Emission Avoidance by Co-production: 50%p

Fuel Saving by Co-Production: 27%

Thermogravimetric Experiment100 mg ZnO / 5.5% CH4 / 3.9% O2 / 1400 K

120

4

4.5

H2

80

100

3

3.5

4

60

80

Mas

s %

2

2.5

3

olum

e %

MassCH4O2H2CO2

CO

Mass

CO

40

M

1

1.5

2

Vo CO2

COCO2

CH4

0

20

0

0.5

1

O2

00 5 10 15 20 25

Time / min

0

Production of Syngas and -Conclusions on CoI ZiIron or Zinc

1. Co-Production of Syngas and Metal in Single Reactor;1. Co Production of Syngas and Metal in Single Reactor;

2. Thermo-Neutral Reaction Achieved by Presence of O2;

3 Added Catalyst Possibly not Needed;3. Added Catalyst Possibly not Needed;

4. Coking Avoidance by Presence of O2;

5 Syngas Quality Improved by H O Addition (in situ water-gas5. Syngas Quality Improved by H2O Addition (in situ water-gas

shift);

6 But: Much Further Work Required Particularly on the6. But: Much Further Work Required, Particularly on the

Reaction Kinetics.

Efforts on Carbothermic Reduction of Al O t Al M t lAl2O3 to Al Metal

The current electrochemical Hall-Héroult process suffers from high p genergy requirement and large greenhouse gas emissions.

With carbon or CH4 as reducing agents, the overall desired reactionsWith carbon or CH4 as reducing agents, the overall desired reactions are:

Al2O3 + 3C = 2Al + 3CO ΔHo298K = 1344.1 kJ mol-1

Al2O3 + 3CH4 = 2Al + 3CO + 6H2 ΔHo298K = 1568.7 kJ mol-1

Halmann, Frei, Steinfeld, Energy, 32, 2420, 2007

Equilibrium Distribution vs. Temperature for the bar1C at3+OSystem Al bar1 C at 3+ 3O2System Al

2007, 2420, 32Halmann, Frei, Steinfeld, Energy,

3

3.5COC(gr)

2

2.5

ts, m

oles

CO(g)Al(g)

Al(g)

1

1.5

Prod

uct Al(g)

Al2O(g)C(gr)Al4C3(s)

Al2O3

Al2O

0

0.5

2000 2500 3000

Al4C3(s)Al2O3(s)

2

2000 2500 3000

Temperature, K

Induction Furnace Carbothermic Reduction of Alumina

The production of Al and CO, as well as the aluminum carboxides Al2OC, Al4O4C, and the carbide Al4C3 was achieved by heat pulses from an induction furnace on mixtures of Al2O3 and pu ses o a duct o u ace o tu es o 2O3 a dactivated carbon in an Ar stream.

The formation of these species was proven by gas chromatography for the CO, and by XRD analysis for the solid products on the cold reactor wall, as shown in the next slide:p ,

160 C

140

160

Al2

OC

120

ts

Al4

C3

Al2

OC A

l

80

100

Cou

nt

Al4

C3

C3

Al

60

80

Al4

C A

4035 40 45 50 55 60

Position (°2 Theta)

Production -Conclusions on Carbothermic Cof Al d COof Al and CO

1. The Carbothermic Al Production is Complicated by Co-Production p yof Al-Carbide and Al-Oxy-Carbides.

2. Further Work Required to Obtain Al without these Carbides.

3. The Conversion of the CO Product to Syngas should Improve the Economics of the Process.

4. The Carbothermic Production of Al would avoid the Environmental4. The Carbothermic Production of Al would avoid the Environmental Problems and High Energy Consumption of the Electrolytic Hall-Héroult Process.

5. A Successful Solar Carbothermic Process for Al and Methanol Co-Production could potentially achieve up to ~52% decrease in CO2

Emissions and up to ~ 81% Fuel Savings.p g

Industrial Production of Magnesium:

1. Silicothermic Reduction of Calcined Dolomite, CaMg(CO3)2, Pioneered by Loyd M. Pidgeon in g( 3)2, y y gCanada during World War II.

Afterwards replaced by the

2. Electrochemical Reduction of Fused Magnesium Chloride, derived from Brine Lakes, such as the D d S f S t i l i thDead Sea, or from Seawater – mainly in the U.S.A., Russia, Canada, and Israel.

–World Primary Magnesium Production )2006T / (i000726b )2006Ton/year (in 000 ,726about

Of these produced in:Of these produced in:China: 526,000 TonC d 50 000 TCanada: 50,000 TonRussia: 50,000 TonU.S.A. 43,000 TonIsrael: 28,000 TonKazakhstan: 20,000 Ton

U.S.Geological Survey, 2007U.S.Geological Survey, 2007www.intlmag.org

The Three Steps of the Pidgeon ProcessThe Three Steps of the Pidgeon Process

1. Calcination of Dolomite,

CaMg(CO3)2 = CaO + MgO + 2CO2

2 Ferrosilicon Alloy Production2. Ferrosilicon Alloy Production ,

Fe2O3 + 4SiO2 + 11C = 2(Fe)Si2 + 11CO

3. Silicothermic Reduction of MgO by Ferrosilicon,

2MgO + 2CaO + (Fe)Si = 2Mg(g) + Ca2SiO4(s) + Feg ( ) g(g) 2 4( )

Toguri and Pidgeon, Can. J. Chem., 40, 1769 (1962)

Energy Consumption and Greenhouse Gas Emissions in the Industrial Pidgeon Process

From Ramakrishnan, Koltun, 2004, 49, 42Resources, Conservation & Recycling,

Global Warming Impact

kg CO /kg Mg

Energy Consumption

MJ/kg Mg Ingot

Reaction Steps

kg CO2eq/kg Mg Ingot

MJ/kg Mg Ingot

10.152.1Dolomite Calcination

14 7113 5Ferrosilicon 14.7113.5Ferrosilicon Production

15.9181.4MgO Reduction by Ferrosilicon

st Step of the Pidgeon Process1The p g

Calcination of Dolomite,Calcination of Dolomite,at ~1300o C,

CaMg(CO3)2 = CaO + MgO + 2CO2

Highly Endothermic Reaction, g y ,CO2 Released both from the Reaction, and from Fuel Burned for Process Heat.and from Fuel Burned for Process Heat.

Equilibrium Composition vs. Temperature for the Calcination of CaMg(CO3)2

initially at 300 K and 1 barHalmann, Frei, Steinfeld, Ind. Eng. Chem. Res., 47 , 2146, 2008, , f , g , , ,

2

2.5

es

CO2

1

1.5

2

cts,

mol

e

DolomiteMgOCO2

MgOCaMg(CO3)2

0

0.5

1

Prod

u CO2CaOCaO

0600 800 1000 1200

Temperature, KTemperature, K

nd Step of the Pidgeon Process2The nd Step of the Pidgeon Process2The Ferrosilicon Alloy Production

by Electric Arc through Mixture of y gHematite, Quartz Sand, and Coal. Extremely Endothermic Reaction;Extremely Endothermic Reaction;

Emits Toxic CO.

Literature Reported Reaction:

Fe2O3 + 4SiO2 + 11C = 2(Fe)Si2 + 11CO

Equilibrium Composition vs. Temperature for the System

Fe2O3 + 4SiO2 + 11C at 1 bar12

10

12

les

FeSi

CO

C(gr)

6

8

cts,

mol

FeSiSiCCO

C(gr)

2

4

Prod

uc SiO2C(gr)FeSi

SiO2

0

2

1500 2000

SiO

1500 2000

Temperature, K

Thermogravimetric ExperimentThermogravimetric ExperimentPurpose of experiment:

To test if for Ferrosilicon Production, the Customary Internal Heating by an Electric Arc could be Replaced by External Heating, Potentially with Concentrated Solar Energy.

Expected Reaction from Literature:Expected Reaction from Literature:

Fe2O3 + 4SiO2 + 11C = 2(Fe)Si2 + 11CO

A mixture of hematite, quartz sand and active carbon, q

was heated under constant Ar flow in a high-temperature thermogravimeter.

Observed Reaction in Present work:

Fe2O3 + 4SiO2 + 11C = 2FeSi+10CO+SiC+SiO

Evolved gases measured by gas chromatography. g y g g p ySolid products analyzed by X-ray diffraction.

2008, 2146, 47Halmann, Frei, Steinfeld, Industrial Eng. Chem. Res.,

XRD of the Solid Product of the Reaction Fe2O3 + 4SiO2 + 11C = 2FeSi + SiC + 10CO + SiOe2O3 S O2 C eS S C 0CO S O

Identified FeSi and SiC

I lIm p ulse

C

Fe S

i 7 0 0 1 _ 1 .rd

4 0 0 0

e Si i

Si C

Fe S

i

2 0 0 0

Fe

Fe S

Fe S

i

Si C Si

C

e Si

Fe

P o s itio n [°2 The ta ]

3 0 4 0 5 0 6 0 7 0 8 0

0

rd Step of the Pidgeon Process3The rd Step of the Pidgeon Process3The

Silicothermic Reduction of MgO by Ferrosilicon,,

at ~1200-1500oC under Vacuum. Highly Endothermic Reaction,Highly Endothermic Reaction,

2MgO + 2CaO + (Fe)Si =2MgO + 2CaO + (Fe)Si = 2Mg(g) + Ca2SiO4(s) + Fe

P d t G M dProducts: Gaseous Mg and Slag of Dicalcium Silicate.

Equilibrium Composition vs. Temperature at 10-5 bar for the System

Si + 2MgO + 2CaO

22.5

s

1.52

s , m

oles Mg(g)

Ca2SiO4

0.51

Prod

ucts MgO(s)

01000 1500 2000

Temperature, K

Potential Fuel Savings and CO2 Emission Avoidance in a Solar Pidgeon Process Combined with Conversion of Syngas (if formed) to Methanol –

vs. Conventional Processes.

CO2 Emission Avoidance, %

Fuel Savings, %Process Steps

D l it C l i tiDolomite Calcination

44.0100CaMg(CO2)3 = CaO+MgO+2CO2

22.355.4CaMg(CO2)3+20C +40H2O= CaO+MgO+26.3H2+13.5CO+13.6H2O+8.4CO2

99.738.6CaMg(CO2)3 + 4CH4 =CaO+MgO+7.8H2+3.9CO+ 2C(gr)g 2 (g )

Ferrosilicon Production

94.790.7Fe2O3+4SiO2+11C = 94.790.72 3 22FeSi+10CO+SiC+SiO

Reduction of Calcined Dolomite

10099 2Si + 2MgO + 2CaO = 10099.2Si + 2MgO + 2CaO 2Mg(g) + Ca2SiO4(s)

Conclusions on Modifications to Pid PPidgeon Process

1. Considerable Fuel Savings and CO2 Emission Avoidance g 2Predicted in all Three Steps of the Pidgeon Process by using Concentrated Solar Energy for Process Heat.

2. For Dolomite Calcination, and for Ferrosilicon Production, Additional Fuel Saving and CO2 Emission Avoidance Possible by using CH or C + H O as Reductant resulting in Coby using CH4 or C + H2O as Reductant, resulting in Co-Production of Syngas.

3. Half-Calcined Dolomite, CaCO3-MgO, is useful forReversible Moderate-Temperature (~800K) Capture of CO2and SO2.and SO2.

Ammonia Production by a Cyclic Process via Al i d Al i Nit idAlumina and Aluminum Nitride

The production of NH3 by a two-step cyclic process was tested as an alternative to itscurrent industrial production by the Haber-Bosch process.

The first, endothermic step, is the production of AlN by the reduction of Al2O3 withcarbon in a N2 atmosphere above 1300°C:

Al2O3 + 3C + N2 = 2AlN + 3CO2 3 2The CO may be “water-gas” shifted to syngas.The second, exothermic step, is the steam-hydrolysis of AlN to produce NH3 and reform

Al2O3 below 375°C; the latter is recycled to the first step:2AlN + 3H2O = Al2O3 + 2NH3Advantages:1) No need for high pressure; 2) No need for expensive catalysts;2) No need for expensive catalysts; 3) Petcoke or charcoal as feedstock instead of hydrogen; But:Pure N2 required as feedstock.Pure N2 required as feedstock.

Gálvez, Halmann, Steinfeld, Ind. Eng. Chem. Res. 46, 2042, 2007

Gálvez et al, Ind. Eng. Chem. Res. 47, 2231,2008

Conclusions: Principles of Process Improvements

1. Combining heat absorbing and heat releasing g g gchemical reactions.

2 Combining CO emitting and CO consuming2. Combining CO2 emitting and CO2 consuming reactions.

3. Lowering the temperature required for gas-releasing reactions by decreased gas pressure.

4. Substituting concentrated solar energy instead of fuel combustion for process heat.p

Scope for Collaboration of Different I d i C b MIndustries on Carbon Management

1. Between the Petrochemical and Metallurgical Industries1. Between the Petrochemical and Metallurgical Industries on the Co-Production of Metals and Syngas;

2. Between the Petrochemical and Lime (and Cement) Industries on the Co-Production of Lime and Syngas;y g ;

3. Between the Automobile and Electrochemical Industries3. Between the Automobile and Electrochemical Industries on the Development of Ammonia Fuel Cells for Carbon-Free Emissions.