Ammonia Production for Renewable Energy Storage Shanwen Tao

University of Strathclyde H2FC Supergen Hydrogen and Fuel Cell Hub meeting 13:35-14:00, Room: Crombie A, All-Energy, AECC, Aberdeen, 21st May 2013

Intermittence of renewable energy sources

http://integrating-renewables.org/grid-impacts/ 2

Volumetric versus gravimetric energy density of the most important energy carriers

A. Zuttel, A. Remhof, A. Borgschulte, O. Friedrichs, Philos Trans R Soc AMath Phys Eng Sci 368 (2010) 3329 - 3342.

Electrochemical Synthesis

CO2

CO CxHy

H2O

H2

N2

NH3

Syngas

Organic compounds /polymers

Chemicals can be synthesised from CO2

Peter Skyring, Carbon capture and utilisation in the green economy, 2012

5

World renewable electricity production

http://en.wikipedia.org/wiki/List_of_countries_by_electricity_production_from_renewable_sources 6

CO2 emission from power generation

http://www.world-nuclear.org/education/comparativeco2.html To convert 1000g CO2 into CO, at 2V, need 2.43 kWh energy 1kWh can convert 411g CO2 (at 100% Faraday efficiency) 7

World hydrogen production and consumption

In 2002 http://www.eoearth.org/article/The_Hydrogen_Economy?topic¼60603.

Comparison of different energy carriers

Rong Lan, John T.S. Irvine, Shanwen Tao*, Inter. J. Hydrogen Energy, 37 (2012) 1482-1494.

Diagram of ‘Ammonia Economy’

Biosynthesis

Natural gas

Coal

Biosynthesis

Haber -Bosch process N 2 (g ) + 3H 2 (g )  2 NH 3 (g )

Artificial Photosynthesis

Wind

CO2 -free e lectricity

Ammonia

Solar

2 N 2 ( g ) + 6H 2O  4 NH 3 ( g ) + 3O2 ( g )

Biomass

Wave

Nuclear H 2

Artificial Photosynthesis Storage

Nuclear Delivery

CO2 scrubbing

Ammo nia fuel cell

Urea fuel cell

Urea

Transportation

Rong Lan, John T.S. Irvine, Shanwen Tao*, Inter. J. Hydrogen Energy, 37 (2012) 1482-1494.

To convert a normal car to NH3 car

Note: cost a couple of thousands US$ to convert; can run either petrol or NH3

http://www.nh3car.com/how.htm

Haber-Bosch NH3 Synthesis

http://www.greener-industry.org.uk/pages/ammonia/6AmmoniaPMHaber.htm

Global NH3 production and CO2 emission

245 million tons of CO2 released World CO2 emission 2012: 35.6 billion tons ~ 0.7% CO2 is from ammonia industry Consuming 1% of world energy generated http://www.fertilizer.org/ifa/HomePage/SUSTAINABILITY/Climatechange/Emissions-from-production.html

Norsk Hydro Rjukan Norsk Hydro Rjukan is an industrial facility operated by Norsk Hydro at Rjukan in Tinn, Norway, from 1911 to 1991. The plant manufactured chemicals related to the production of fertilizer, including ammonia, potassium nitrate, heavy water and hydrogen. The location was chosen for its vicinity to hydroelectric power plants built in the Måna river. 30 million tonnes of products, equivalent of 1.5 million wagon loads, were produced in Rjukan.

http://en.wikipedia.org/wiki/Norsk_Hydro_Rjukan

Hydroelectricity to NH3 synthesis

http://www.hydroworld.com/articles/hr/print/volume-28/issue7/articles/renewable-fuels-manufacturing.html

Wholesale NH3 price in the USA

http://www.hydroworld.com/articles/hr/print/volume-28/issue7/articles/renewable-fuels-manufacturing.html

Price of NH3 using different synthesis methods

Cost of Ammonia Produced Using Haber-Bosch Synthesis Technology

Cost of Ammonia Produced Using Solid State (Electrochemical) Synthesis Technology http://www.hydroworld.com/articles/hr/print/volume-28/issue7/articles/renewable-fuels-manufacturing.html

Electrochemical synthesis of ammonia

http://freedomfertilizer.com/

Principles of electrochemical synthesis of ammonia

I.A. Amar, R. Lan, C. Petit and S.W. Tao, J. Solid State Electrochem. 15 (2011) 2845. 19

Summary of reported ammonia formation rates

20

Nitrogen fixation by legume crops

http://permaculturetokyo.blogspot.co.uk/2009_02_01_archive.html http://www-naweb.iaea.org/nafa/swmn/topic-soil-fertility.html 21

Thermodynamic evaluation of ammonia synthesis process 1.4

(A)

700

(B)

1.2

Minimum required voltage (V)

Gibbs free energy change (kJ mol-1)

800

600 500

N2(g)+3H2(g)=2NH3(g)

400

N2(g)+3H2O(g)=2NH3(g)+3/2O2(g) 300

N2(g)+3H2O(l)=2NH3(g)+3/2O2(g)

200 100 0 -100

1.0 0.8

N2(g)+3H2(g)=2NH3(g) N2(g)+3H2O(g)=2NH3(g)+3/2O2(g)

0.6

N2(g)+3H2O(l)=2NH3(g)+3/2O2(g)

0.4 0.2 0.0 -0.2

0

100

200

300

400

500

600

Temperature (°C)

700

800

900

1000

0

100

200

300

400

500

600

700

800

900

1000

Temperature (°C)

(A) The Gibbs free energy change for electrochemical synthesis of ammonia from N 2 and H2, N2 and H2O (gaseous or liquid) at pressure of 1 bar; (B) The minimum applied voltage required for electrochemical synthesis of ammonia from N2 and H2 at pressure of 1 bar (the negative voltage at a temperature below 200 C means spontaneously generated voltage), N2 and H2O (gaseous or liquid). 22

Synthesis of ammonia from H2 and N2 800

600

3.5

500

1.2 (C)

3.0

1.0

400 300

-5

200 100 0

10

20

30

40

50

60

Time (min.)

4

70 0.8

on air side on H2 side

3

0.6

total Farady efficiency 2

0.4

1

0.2

0 0.0

0.2

0.4

0.6

0.8

Applied voltage (V)

1.0

Farady efficiency (%)

NH3 formation rate (x10-5 mol m-2 s-1)

(B)

2.5 0.8

2.0 0.6

1.5 0.4

1.0

formed NH3 applied voltage

0.5 0.0 0

60

120

180

240

Applied voltage (V)

Formed NH3 (x10 mol)

2

Current density (mA/cm )

applied 0.2V applied 0.4V applied 0.6V applied 0.8V applied 1.0V

(A)

700

0.2

0.0 300

Time (min.)

0.0 1.2

(A) Current density of a N2, Pt  Nafion 211  Pt, H2 cell under different applied voltages. Cathode was supplied with N2, anode was supplied with H2. (B) The ammonia formation rate at N2 and H2 sides, total ammonia formation rate and Faday efficiency. (C) The relationship between formed NH3 and time of a N2, Pt  Nafion 211  Pt, H2 cell under different applied voltages. Cathode was supplied with N2, anode was supplied with H2 23

Synthesis of ammonia from H2 and air 600

applied 0.2V applied 0.4V applied 0.6V applied 0.8V applied 1.0V applied 1.2V

(A)

400

3.0

1.4 (C)

300

1.2

2.5

200

-5

100

1.0

2.0

0 0

10

20

30

40

50

60

Time (min.) 4

2.5

-1

at H2 side

3

2.0

Farady efficiency 1.5

2 1.0

1 0.5

0 0.0

Farady efficiency (%)

Total

-5

NH3 formation rate (x10 mol m s )

at N2 side

-2

(B)

0.8

1.5 0.6

1.0 formed NH3

0.4

Applied voltage (V)

Formed NH3 (x10 mol)

Current density (mA cm-2)

500

applied voltage

0.5

0.2

0.0 0

60

120

180

240

300

0.0 360

Time (min.)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

Applied voltage (V)

(A) Current density of an Air Pt  Nafion 211  Pt, H2 cell under different applied voltages. Cathode was supplied with air, anode was supplied with H2. (B) The ammonia formation rate at air and H2 sides, total ammonia formation rate and Farady efficiency. (C) The relationship between formed NH3 and time of an Air, Pt  Nafion 211  Pt, H2 cell under different applied voltages. Cathode was supplied with air, anode was supplied with H2. 24

Synthesis of ammonia from H2O and air 90 applied 1.2V applied 1.3V applied 1.4V applied 1.5V applied 1.6V

(A) -2

1.5 (C)

-5

50

0

10

20

30

40

50

60

70

Time (min.) 1.2

0.6

(B) 0.5

on air side on H2O side

0.8

0.4

total Farady efficiency

0.6

0.3

0.4

0.2

0.2

0.1

0.0 1.1

1.2

1.3

1.4

1.5

1.6

0.0 1.7

Farady efficiency (%)

1.0

1.5

0.9 1.4

0.6 1.3

0.3

formed NH3 applied voltage

0.0 0

60

120

180

240

Applied voltage (V)

1.6

1.2

60

40

NH3 formation rate (x10-5 mol m-2 s-1)

1.7

70

Formed NH3 (x10 mol)

Current density (mA cm )

80

1.2

1.1 300

Time (min.)

Applied voltage (V)

(A) Current density of an Air, Pt  Nafion 211  Pt, H2O cell under different applied voltages. Cathode was supplied with air, anode was supplied with H2O. (B) The ammonia formation rate at air and H2O sides, total ammonia formation rate and Farady efficiency. (C) The relationship between formed NH3 and time of an Air, Pt  Nafion 211  Pt, H2O cell under different applied voltages. Cathode was supplied with air, anode was supplied with H2O. 25

Synthesis of ammonia from air and water

26

Rong Lan, John T.S. Irvine, Shanwen Tao, Scientific Reports (Nature Publishing Group), 3 (2013) 1145.

NH3 formation rate and Faraday efficiency when low cost catalysts were used 6

3.0 NH3 formation rate Faraday efficiency

2.5

5 4

2.0 3 1.5 2

1.0

1

0.5 0.0 1.2

1.3

1.4

1.5

1.6

Faraday efficiency (%)

NH3 formation rate (x10-4 mol m-2 s-1)

3.5

0 1.7

Applied voltage (V)

Note: NH3 formation rates are over 10 times higher than those when Pt/C was used as catalysts.

Stability of a electrochemical cell using low cost catalysts at both electrodes 250 225 200

Current (mA)

175 150 125 100

Current at 1.3V

75 50 25 0 0

10

20

30

40

Time (hour)

50

60

70

28

Summary • It has been demonstrated that ammonia can be synthesised directly from air and water at ambient temperature and pressure. • Ammonia is an important energy carrier for energy storage. • Ammonia has been produced from renewable electricity. • Price of ammonia produced from renewable electricity depends on the price of electricity, will be competitive. • Unlike extra cost for CO2 capture, storage and transportation for synthesis of hydrocarbons, ammonia can be on site synthesised directly from air and water. 29

Acknowledgements Professor John T.S. Irvine at University of St Andrews Dr Rong Lan Mr Ibrahim Amar Other RAs and students in my group