corrosion

Anhydrous ammonia is not normally considered corrosive either to carbon steel or to the stainless steels or aluminum. It is a bad match with most copper alloys, except for silicon bronze, which might be used in seals or bearings.

I don't know the total picture in a urea plant, but your corrosion problem may be coming from some other source. What else could be splashing on your tanks to create the droplet appearance you mention?

You'll have to be more specific about which SS you're using, and what sort of urea production. It varies greatly.

For example, I found that 304 has a 0.078 inch per year corrosion rate in 12% ammonia, 7% CO_2, remainder water, half immersed, while 316 has only 0.019 inch per year. If you lower the CO₂ concentration, the corrosion rate improves.

Now, of course, I don't know if you have any CO₂. I'm just using that as an example of why you have to say more.

is your plant located near the sea? it could be also atmospheric corrosion..

S

corrosion prevention & control

yes what you said is correct. My Plant safco(SABIC)is located very nearer , 0.5 km away from sea.it could be reason.

Thanks and Regards,

Raju Mendu suvarna

Hello Raju,

What kind of corrosion you see ?

If it are cracks from outside, it indeed could be chloride stress corrosion cracking.

Temperature should be higher than 50 degC and moisture should be present.

Best regards

Mark Brouwer

www.ureaknowhow.com