How not to explode a storage tank for dummies (or process engineers)

There are many ways to explode tanks, but since our time is finite, I'm gonna teach you only one way of how not to do so (as a process engineer). I have to confess, I'm sick of seeing images of tanks imploding and exploding. Of course it can happen for a lot of reasons, so I picked one to explain to you how to avoid it.

Biology lesson 1: Tanks breaths

That's true, tanks breathe all the time, they need to, and when they don't...

Lesson 2: Mass balance

There are many types of storage tanks. Some of them are opened (vented), and others are closed, and the primary thing they have in common is you! The folk who brought it alive (or inherited it).

But for simplification, let's work with the atmospheric.

When filling in a tank we are injecting volume at a fixed rate, if you don't want to increase pressure you must fill out something at the same rate.

But what should I fill out? How?

AIR!!! WITH A VENT.

If you noticed it says "vent with cage". I don't know if this is story for kids but my teachers said they have seen birds making nests in those pipes. Well, then you must account for the BIRD NEST AS WELL!

After you have your tank in operation, every time you fill in and out, air will be added or released by the vent. Not only that, but the hot sun on the walls of the tank and the cold desert night can significantly affect one's density and vaporization/condensation.

Lesson 3: Sizing a vent

If your vent is too big, big things (or more) can go inside, if your vent is too little, the tank won't breathe. The best option is to size it accordingly + safety margin.

If you didn't know, there is plenty of self-explanatory documentation to size these things, in our example the one I would recommend is:

• API 2000 for atmospheric and low-pressure tanks.

The API states the conditions you should consider and how much air your vent should be able to handle. After that, simple math or process simulation can easily manage it.

Let me know what you think.

Thanks for reading it!

For my next post, I intend to show how to calculate it using a free source process simulator (DWSIM).