Formation of Hydrogen in Fume Duct

Hi,

you are absolutely right:

any corrosion of iron will produce hydrogen!

From Fe and 2 H2O is generated Fe(OH)2 the dark green coloured iron hydroxide.

This in turn will be oxidised to a mixture of Fe-OOH and Fe(OH)3 if there is enough oxygen available. At higher temperatures Fe2O3 and Fe3O4 are resulting by treatment of iron with hot (500 to 600°C) steam.

Any of these reactions will strip a fraction or all hydrogen from the water molecule and let it go somewhere: sometimes quite dangerous.

There was a near failure of a big suspended bridge (1.6km long) crossing the harbour of Hamburg, Germany because the suspension steel wires were encapsulated good enough to keep some hydrogen inside the encapsulation and not good enough to hold the moisture out completely.

So the small amount of hydrogen caused hydrogen embrittlement to the high strength highly stressed wires. As this was detected half of the wires were broken, some months later the bridge would have shown a spectacular collapse.

For a fast generation of hydrogen its better to use iron and sulfuric acid.

RHABE