al water summary r2

8/2/2019 Al Water Summary r2

1/17

SPLITTING ANY KIND OF WATER WITHGLOBAL-SCALE, EARTH-ABUNDANT, LIGHT,

RECYCLABLE METALS TO MAKEHYDROGEN, HEAT AND

POTABLE WATER ON DEMANDJerry M Woodall

National Medal of Technology Laureate

Epstein Distinguished Professor of ECE

Purdue University


2/17

Why isnt there a global scale hydrogen energy economy?

Small volume energy density

High pressure gas and low temperature

liquid storage expensive and dangerous

Hydrogen transport dangerous and expensive

Solution: use a safe, cheap, earth-abundant high energydensity material for storage and transport that can

react with water to make hydrogen on demand

Is there such a material? Yes! Its ALUMINUM!

If aluminum could split water the chemistry would be:

2Al + 6H2O 3H2 + Al2O3:3H2O


3/17

Aluminum has the highest volumetricenergy density ofanything on the chart

and a higher mass energy density than

ethanol, methanol or bituminous coal!


4/17

Mass Energy Densities of Interest

As hydrogen from splitting water:

1 Kg H2: 142 MJ = 39.4 kWh combustible energy 1 Kg Al makes 111 g of H2 from 2 Kg of H2O = 4.4 kWh

1 gal (10 Kg) Al makes 44 kWh as hydrogen

1 gal. diesel: 37 kWh

1 gal. liquid hydrogen: 10 kWh

As heat from splitting water:

1 Kg Al: 4.4 kWh

Total energy, 1 Kg Al: 8.8 kWh (1Kg coal: 6.7 kWh!)Energy to electrolyze alumina to 1 Kg of Al: 12.9 kWh

Total energy efficiency: (8.8/12.9) x 100 = 68%

H2 energy efficiency: (4.4/12.9) x 100 = 34%


5/17

Technology sustainability & large scale use

World Supply:

Al reserve in the planets crust: about 1013 Kg (as Al);

1.2 x 1012 Kg of H2 made by splitting water = 5 x 1013 kWhrs

of H2 energy

Current worldwide annual Al production: 32 billion Kg from

bauxite;

400 billion Kg of scrap impure elemental Al; amount

needed to supply 12% US annual energy consumption of

about 100 quad BTU. Since all Al that is converted to an

oxide can be recycled back to metallic Al via electricity

from any source, Al is a global scale alternative energy

storage material with almost no carbon footprint.


6/17

WHAT CAN WE MAKE? Buy scrap or metallurgical grade, i.e. cheap, Al, melt itwith Ga and Sn, then cool it to make solid, bulk like Al

rich alloys up to 93 wt% solid Al grains, and 6.2 wt% Ga,and 0. 8 wt% Sn liquid in the grain boundaries that splitsany kind of liquid water, e.g. sea water, dirty water andpolluted water, at between 20 C and 100 C and make H2,heat, including superheated steam, on demand and

aluminum hydroxide powder Buy 95% Al, 5% Sn vendor alloy, contact with a liquidmixture of 7 wt% Ga and 1 wt% Sn, and then with water;this splits any kind of liquid water at temperatures

between 20 C and 100 C and make H2, heat, includingsuperheat steam, on demand and aluminum hydroxidepowder

Recover/separate inert Ga and Sn from hydroxidepowder and recycle indefinitely


7/17


8/17

A sample of Al-GalInSn* splitting water

Using scrap Al and

recovering the GaInSncomponent, the cost/kWh of

our hydrogen/compared

to other fuels:

Coal: $0.004Natural Gas: $0.06

Al: $0.10

Gasoline: $0.09 (at $3.00/gallon)

Li ion battery: $4.00

*GaInSn is liquid at room temperature


9/17

2Al(GaInSn) + 6H2O* 3H2 + 2Al(OH)3 + GaInSn

3H2 + 3/2O2 3H2O; we get back half the water when we use the H2;we get rest of the water + the Al back via smelting; the GaInSn is inert

* Including salt water

2 Al(OH)3 + heat Al2O3 + 3 H2O + electricity 2 Al

Bottom line: You get all the water back as potable water!


10/17

Legend:

= Aluminum= Ga-In-Sn

= Hydroxide

= Hydrogen gas

Al-Ga

grain

Alloy Water

At room temperature, the Ga-In-Sn phase is liquid! The solid Al grains are able to dissolve into and move freely through the

liquid phase. Al near the surface contacts the water interface. The ensuing exothermic reaction produces hydrogen as the Al is

oxidized. This reaction proceeds until all the Al grains split the water into hydrogen gas and aluminum hydroxide

How it works!


11/17

Abundance:Al: crustal abundance 8%Ga: crustal abundance 0.002%

Sn: crustal abundance 0.0002%

Sustainability:Al: annual production 32 billion kg

Ga: annual production 184 million kgSn: annual production 165 million kg

Therefore, as long as the Ga and the Sn arerecycled there is no Ga abundance or productionproblem


12/17

Energy Source

(wind, solar, nuclear,

geothermal, etc)

(-12.9 kWh/kg-Al)

Application(fuel cell, combustion

engine)

Water

Aluminum

Alloy

Aluminum

Hydroxide

Heat

(+4.4 kWh/kg-Al)

Energy

Water

Reaction

Hydrogen

(+4.4 kWh/kg-Al)

The Aluminum-Hydrogen Cycle

CO2

Sequestered


13/17

Example applications:

Replace batteries with a Ga-Al-H20/fuel cell

system for high energy density electric power applications:

emergency/stand-by power (AlGalCo)

electric wheel chairs, golf carts, utility vehicles

PDAs, Laptops, etc.

hybrid and fuel cell powered cars

Stirling engines

replace gasoline for HEVs (GM Volt)

liquid fuel multiplier, e.g. diesel enrichment

trains, boats, ships, subs, trucks large boats and other maritime applications

off-grid/remote power + desalinated/potable water!

integrated utilities with solar farms/wind turbines

Other applications:


14/17

Enabling Wind or Solar as Base LoadElectricity Generation Capacity

Target cost: $0.10/kWhr, assuming 40x alloy

recyclingAll required technologies are known

Primarily an Engineering Development Project

Enables Environmentally Sound and Secure

Electricity


15/17

reaction tank,

95-5 alloy, and

controlsH20

H2, 4.4 kWh/Kg-alloy

24/7 or on demand

Fuel Cell or Gas

Turbine/Generator

H20

Electricity

Heat, 4.4 kWh/Kg-alloy

24/7 or on demand

Steam Turbine

alumina,

Ga,In,Sn + H20

component separationH20

Ga,In,Sn recovery

alumina electrolysis

12.9 kW-Hrs/Kg Al

95-5 alloy

regeneration

intermittent

electrical power, e.g.solar or wind

Enabling Wind or Solar as Base Load

Electric Power Model Flow Diagram

CONSUMER


16/17

CAN BE DONE FOR $1/GAL OF WATER AND $0.34/kWh OF ELECTRICITY


17/17

ALUMINUM! A GLOBAL-SCALE, EARTH-ABUNDANT,HIGH ENERGY DENSITY STORAGE

MATERIAL FOR SPLITTING ANY KIND OFWATER TO MAKE HYDROGEN, HEAT ANDPOTABLE WATER ON DEMAND

ONCE YOU BUY IT, IT IS YOURS FOREVER;UNLIKE FOSSIL FUELS IT STAYS IN THE

ENERGY SYSTEM.

THE BOTTOM LINE:

al water summary r2

Documents