Ammonia Storage Tank Re-commissioning

[kjnpanikker]

We have decommissioned a 30 year old 20,000MT capacity double walled Atmospheric storage tank and inspection and reinsulation work is in progress. For recommissinoning we have seen some recomendation for puting some water to cover the tank botom plate before starting ammonia purge to avoid SCC. Earliear we commissioned similar tanks with out adding any water. We are planing to reduce the Oxygen percentage to less than 0.5%. My question is whether we can avoid water filling if the oxygen percentage is less than 0.5%.