7 replies to this topic

[hamadzzz]

Dear professional s,

I Would like to know more about the standard of ISO tank Container unloding process ,If the container is used to carrying out 98% Sulphuric Acid
the suppler informed us that N2 must be used to pressurized the tanker during unloading other wise this will cause damage for their ISO-TANKER ,but at the main time we don’t have N2 facility to do this process .
i give them proposal to use N2 cylinder do the same job .
my question here , is the proposal will work to do the N2 purging .
Thank for all
Your feedback is highly appreciated
Best Regard
HGA
hgazzz@hotmail.com

Edited by hamadzzz, 08 February 2010 - 07:30 AM.

[Art Montemayor]

hamadzzz:

Your inquiry doesn't seem to make good sense. You seem to be trying to unload an Iso Container of Sulfuric Acid by using nitrogen to pressurize the Iso container and transfer the acid to a tanker -- or another vessel. Is that a correct interpretation of what you wrote? If so, then why do you further state: "the suppler informed us that N2 must be used to pressurized the tanker during unloading other wise this will cause damage for their ISO-TANKER ,but at the main time we don’t have N2 facility to do this process"? This seems contradictory and therefore hard to understand.

You can pressurize an Iso container, but you must respect the MAWP (maximum allowable working pressure) assigned to that vessel when you inject nitrogen into it. You must design the nitrogen pressurization system correctly and safely. If you don't know how to do this or haven't the experience, then you should not attempt it.

If you want details, you must first furnish us with all the technical details and a schematic, detailed sketch of the the operation.

I hope this helps you out.

[ponnusj]

hamadzzz,

If I understand your question correctly, supplier has asked you to use N2 for unloading isotanker, but as you do not have the facilities, you have proposed to use N2 cylinders.

My suggestion is do not use N2 cylinders as you may need a considerable number to unload an isotanker load. Ask the supplier if it is OK to use dry air instead of N2. Dry air is required because moisture in wet air can cause corrosion of isotanker internals. Instrument air with a dew point of <-40 degC would be a good choice.

[Dazzler]

The N2 is most likely needed to prevent air and accompanying moisture entering the tanker. Moisture from the air dilutes the SA residue on the walls and so making it more dilute. Some cheaper material tanks (carbon or mild steel) will then be attacked (corroded) by the dilute SA, but would have been fine to standup against concentrated SA. Stainless steel tankers may not have such a problem.

Bottle supply may be ok, but regulator capacity will need to be able to deliver more N2 volumetric flow than the unloading pumps volumetric flow, otherwise air will also be sucked in.

Be sure to have a downstream pressure regulator so that flow of N2 stops rather than over pressure the tanker if its vent cap is mistakenly not opened.

Good tanker logistics companies may offer the service of handling the N2 purging for you, perhaps for additional deliver fee.

Dazzler

[hamadzzz]

Thanks for feedback Mr ponnusj ,

100% you understand the issue with PA ,

it was in my mind what you already recommended ,actually there two proposal
1-by N2 cylinder
2- with dry air as you agreed with me

so in this case will ask the supplier to do it with dry air
and will come back to you once they reply to both proposal

best regards’
HGA

[hamadzzz]

Thanks too much for your reply Mr Art Montemayor,

The main concern here we don't have at the site N2 provision.
That is why I am trying to find other way to unload PA if you refer to Mr. Dazzler& Mr. Ponnusj feedback you will get the clear picture.

Let assume that the PA supplier agreed to use dry air what are the requirement that should be available in dry air system ?

Thanks all for your support relay it is great experience

HGA

[ponnusj]

A good source of dry air would be instrument air used in industrial facilities. Do you have this available?

Instrument air is compressed air which is dried by passing it through silica gel or alumina bed adsorbers.

[Technocrat]

But you should check the dry air quality (moisture content) regularly to avoid moisture ingress in the tanker.