4 replies to this topic

[rahul yadav]

i am preparing tank cool down procedure, my client asked, why product purging required after N2 interting. 

I told that to stop sub-cooling inside the tank, when product % more than 95% vol. after that we start cool-down process.
Again my client is asking, why you required more than 95%?

I did not get any valid basis if you have any guideline.

[fallah]

rahul yadav,

 

Please submit the whole story about the tank, its content,...to get a proper response...

[rahul yadav]

Sir,

 

I have new construct Propylene storage tank (Temp. -45*C), am preparing pre-commissioning procedure for TANK COOL DOWN.   

[Napo]

Dear Rahul Yadav,

 

Propylene is extremely flammable (danger R12). With nitrogen, over 11,5% Oxygen can be ignition therefore, 9% of oxygen is the porcentage recommended (Storch de Gracia J.M., Industrial Security Manual in Chemical and Oil Plants, Vol. 2, McGraw-Hill, 1998, in Spanish).

 

You can review in Perry Chemical Engineer Handbook, 7th ed., section 26, p.77, the following recommendation:

"Inert Gas Generation.- Nitrogen is often the preferred gas for providing an inert atmosphere. In general, most organic combustible compounds will not propagate flame if oxygen in the mixtures of the organic vapor, inert gas, and air is below about 10 percent and 13 percent, with nitrogen and carbon dioxide, respectively, as the inert gases."

 

Your specification (procedure) exceeds the recommendations. I think if you can reach 95% you can be sure.

 

I hope help you.

 

Regards,

 

Napo.

[rahul yadav]

Dear Napo sir,

 

Thanks for your reply, 

 

I need guideline for product purging,