#  > Petroleum Industry Zone >  > Safety And Environment >  >  >  Q;Nitrogen Calculation Formula

## nael

Dear friends 
 I need the calculation  formula to calculate the(flow rate value and the volume  of nitrogen required to purge 
1-Storage tanks 
2- Pipelines 



thanks for you helpSee More: Q;Nitrogen Calculation Formula

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## aseptman

yes, pl enlight anyone

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## ARMOFI

Just get into WELD SPECIALTY SUPPLY CORP. You will see their xlspread sheet there. Send me mail address if you do not get it. I send the file. I am unable to attach here.

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## ARMOFI

You will find it here.

**[link Point to another website Only the registered members can access]
*link*




<![CDATA[[Only Registered And Activated Users Can See Links] 

Just cut & paste, you will have the spreadsheet .

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## tsrc8204

Downloaded. :Distracted:

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## jpl860iq

> Just get into WELD SPECIALTY SUPPLY CORP. You will see their xlspread sheet there. Send me mail address if you do not get it. I send the file. I am unable to attach here.



Hi Mr ARMOFI

Thank you very much for you sheet for the Nitrogen calculation.

I'm a student and I would like to know what kind of the book or reference you generally use to determinate elemental composition of oil trought correlation. (%C, %H, %S, %O2, %N2, %Metals (Ni, V, Fe)
Generallay I used several correlation of Riazi.
(Riazi, M. R. (2005). Characterization and Properties of Petroleum Fractions. West Conshohocken, Panjeshahi, M. H.). 
However this one have several errors and the critical thing I don't found well correlation to N2, O2 and Metals.
So for this reason I need you help. Could you bring me some kind of information about the determination of this elemental composition. You sheet it's already program and I could see the correlation employed for the case of N2.

Another addiotal question that I will like to know it is the table of regulation of elemetal composition to be transport a oil. 
What kind of request or law it is necessary to supply for trasport a oil (e.x. %S, %N2, etc)

Finally my mail is: jpl860@gmail.com

Thank so much

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## ARMOFI

Hi,

As far as using of Nitrogen for purging concerned, it depends on the removable of flammable gases inside the pipeline/tank/conduits etc (confined vessel). Particularly , this means Oxygen to a level of 10-12% desirable, the LFL of the content. The level of purging by N2 is dictated by the Client here.(what % oxygen removal required).

Other question I am unable to understand & I think I am not an expert in it. If it is regarding selection of material for oil/liquid transportation, we follow the regulation list 49  CFR Part 192, AppxB. or the selection of materials as per ASME 31.4 / 31.8 or AISI/SAE Classification of metal. Obviously these are API 5L pipes of different schedule & grades.

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## josefreitas

thanks for this spreadsheet very useful

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## Afridi

Thanks for info.

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## Roderick

The file can not be found. Please upload again. Thanks.

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## mazharshaikh

thanx 
very uselful

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## mazharshaikh

thanx 
very uselful

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## arielezuanshah

> You will find it here.
> 
> **[link Point to another website Only the registered members can access]
> *link*
> 
> 
> 
> 
> <![CDATA[[Only Registered And Activated Users Can See Links] 
> ...



Sorry, 



How to get the spreadsheet..thanks..See More: Q;Nitrogen Calculation Formula

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## sushantchaturvedi

the nitrogen formula depends on what type of purging you are opting for. There are 4 techniques: Displacement, dilution, pressure cycle purging and evacuation replacement purging. 
The simplest is displacement where the amount of nitrogen required is equal to volume of the equipment. For safety purpose, a margin of 20 % extra is being used.

For Dilution purging, an inert gas preferably nitrogen is used for sweeping out the contents. This is used for tank vapour spaces. However this is not preferred for equipments having dead legs or pockets. The formula is Vn= ln (Ci/Cf); where Vn is number of vessel volumes of inert gas required; Ci is initial concentration of oxygen in vapour space (eg. 21% in air) and Cf is the final concentration of oxygen in vapour space

For pressure cycle purging, the alternative pressurizing and depressurizing is done with inert gas to displace the contents. This helps in removing the contents from the remotest point.

The formula is Cf/Ci= (Pf/Pi)^n; where Cf is the final concentration of oxygen in the vapour space; Ci initial concentration in the vapour space; Pi is the pressure of inert gas cycle; Pf is the pressure of the outlet of the inert pressure cycle which is generally atmosphere hence 1 bar.The volume of inert gas required is Vn=n(P-1)

Evacuation replacement purging is similar to the pressure-cycle method, but uses a vacuum source to first evacuate the vessel and then break the
vacuum using the inert gas. The equipment must be designed to withstand the vacuum. This method is very effective
for equipment that contains many deadlegs and pockets.

The formula is same as pressure swing except (Pi/Pf) is used.

The method to be used depends on the geometry and the nitrogen availability.

Hope this helps

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