Urea UTI reactor is corroding

Letter 10046

Dear sir:

Our urea reactor bottom liner and baffles corroded after 22 months (UTI Plywell) 50% is whitish and 50% is Black from the bottom.

Suresh
- South India

What is the material of construction?

Tom Pullizzi platronica.com Falls Township, PA

Generally this is because of passivation layer loss by operating one of the feed with out passivation air Presence of iron in feed also causes stress corrosion Construction material may be defective partially say at the bottom Please furnish material of construction.

Stefen Edward
- Edingburg, Scotland

Normally uneven corrosion occurs due to poor feed rate and quality, N/C ratio; high inert; chloride and sulphides and also iron precipitated water.

1. Increase liquid ammonia rate
2. Maintain volumetric flow rates
3. Complete primary reaction at the shell level
4. Keep mole ration above 4.4
5. Prevent iron precipitated water
6. Check CO₂ purity - 99.3%

Mike Rowdsger
- Tampezeal, Austria

Normally high corrosion speeds in urea synthesis equipment occur due to lack of passivation.
316 L Urea Grade needs a continuous oxygen suppletion to assure a passive layer builds up.
What are the temperatures in the reactor bottom ?

Mark Brouwer
- Maastricht, The Netherlands