Thermo-chemical energy storage using ammonia
When N2 and H2 combine to form ammonia NH3, the reaction gives off heat.
Heat can be stored by breaking NH3 apart, and then recovered by allowing them to combine again.
The nitrogen, hydrogen, and ammonia is all stored in one tank. Under moderate pressure, the ammonia is liquid so can be drawn off separately Commercial catalysts are used to convert the reactants each way.
There are several advantages:
It is just a matter of whether it is as cheap as other options.
1kW chem solar ammonia dissociation closed loop operated for the first time – a world first!
|Ammonia as an Electrofuel|
Ammonia as a way of storing hydrogen
Ammonia is one way to store hydrogen and has several advantages. It is non-flammable and non-explosive, it can be liquefied under mild conditions, and it has a large weight fraction of hydrogen 17.65% of the mass of ammonia. It has a volumetric hydrogen density about 45% higher than liquid hydrogen.Using a catalyst it can be cracked to produce Hydrogen.
Ammonia can be stored as metal ammine complexes of the form M(NH3)nXm,where M is a metal cation like Mg, Ca, Cr, Ni, and Zn, and X is an anion like Cl or SO4. For example: Mg(NH3)6Cl2 .
It has the same volume density as liquid ammonia, but it is can be stored at room temperature and pressure.
Ammonia can power cars. More
2 NH3 ----> 3 H2+ N2 H° = 46 kJ/mol
Only 16% of the energy stored in ammonia is needed
Ammonia is produced by six producers in Australia; Incitec, Orica, Wesfarmers, BHP-Billiton,
Ammonia is manufactured by the catalytic steam reforming of natural gas. Hydrogen from the reformed natural gas and nitrogen from air are compressed at reduced temperatures to form ammonia:
Some of the CO2 is recovered to make urea and for use in food and drink.
If methane is used to make ammonia then about 1.5 t of CO2 is made per tonne of ammonia produced.