1 reply to this topic

[vishal3992]

Hi All,
I have to design sulfuric acid storage tank, as per API 650. I heard that, vent line on the tank is very important due to hygroscopic nature of acid. As per the documents, vent is connected to other tank.

I want to know, how to model vent? Do I have to worry about relief valve or breathing valve?

The tank is 40X 40 ft, and will be 90% max filled.

Your help on this will be really appreciated.

Regards
GE

[Art Montemayor]

Vishal:

I moved this thread to the Student Forum where I believe it belongs. You are a student and any thorough discussion of the matter and the professional engineering terms involving storage tank relief will be beyond your learnings to date or your current knowledge. In short, you won't understand what we are talking about.

1) What are you designing? Is it a Process Design? Or is it a Mechanical Design? Please be specific.

2) Have you thoroughly read the CSB Report on the Motiva tragedy that I recommended to you?

3) You obviously lack a complete understanding of what you have been assigned to "design" and the hazards involved. Professional engineers do not generate designs based on what they HEAR. You have stated: "I heard that, vent line on the tank is very important". That is hearsay. Don't you have any proof, logic or personal awareness of how important – or unimportant – a vent line is on a sulfuric storage tank? You have to have a complete understanding and domination of all the factors that will enter into the design of this tank. The correct, SAFE design depends entirely on this.

4) What, specific quality of sulfuric acid are you proposing to store? Again, read the CSB Report as I recommended. Is it Spent Acid or Fresh makeup acid? It makes a big difference.

5) You state: "As per the documents, vent is connected to other tank". What documents? What are you referring to, specifically?

6) You state: "I want to know, how to model vent". What do you mean by "model"? I thought you were to design the system.

7) You ask: "Do I have to worry about relief valve or breathing valve?" Of course you do! Haven't you read the CSB Report? Obviously you don't know or understand the principles of tank blanketing or the properties of sulfuric acid.

8) Your state: "The tank is 40X 40 ft, and will be 90% max filled". How is it possible that you already know the size if you haven't mechanically designed the tank? Are you positive that the wind loads and anchoring requirements are sufficient to support the 40 foot height? Do you believe that you can arbitrarily pick just any tank height?

By the litany of questions I have raised and the importance that they play in the process/mechanical design of a storage tank, you can easily see that your knowledge is not up to the requirements for resolving the design of this tank – whether process or mechanical.

Please explain in full detail what you, as a student, are supposed to do on this assignment and detail out all the work, calculations, and research that you have done on this assignment to date. Perhaps we can be of some help to explain some things to you, but we certainly are not going to do your assignment for you NOR are we going to substitute for your professors and teach you how to design a storage tank. That is THEIR job. Your job is to pay attention and learn all the information that they presumably have already taught you. Good luck.