Alternative to Steam-out?

[Ashereng]

To my mechanical colleagues:

I have read many posts in many fora that highlight the problems encountered with steam-out of a tank - primarily, sucking/imploding the tank in on pressure loss due to rapid cooling combined with insufficient vent capacity.

Is the alternative a pressure wash?

What benefit of steam-outs is there that people still use it even though it has collapsed many tanks?

"Do not worry about your problems with mathematics, I assure you mine are far greater."
Albert Einstein
Have you read FAQ731-376 to make the best use of Eng-Tips Forums?

 

[codeeng]

Steam-out typically applies only to vessels and piping which are good for at least half vacuum at about 150C. I've never seen steam-out applied to low pressure or atmospheric tanks.

 

[unclesyd]

Our problem with sucking in tanks has been when trying to empty one and the transfer pump pulls in the tank.

We steam out atmospheric storage tanks on a routine basis for either clean out and or lowering the explosibility numbers. The majority of these tanks have a conservation vent that maintains a couple of inches of H2O pressure on the tank with nitrogen and is left online during steaming. We always open other vents as well.
Due to production demands rotary tank washers have taken over for a lot of the steaming.

We have several products that generate a slime on the tank walls, very flammable and products that freeze at 40°F and 80°F.

The worst incident I've seen on steaming out a tank is when a technician took it upon himself to to steam out a 2000 gal stank about half full of an Isocyanate. Turned the steam on and went to lunch.