The Internal floating roof tank flash point

[fe2386]

Dear all,
I am informed that a internal floating roof tank containing kerosene should be operated with the flash-point higher than ambient temperature otherwise it should be interted.
Is there anyone who knows about that point, please teach me the standards/regulations regarding that issue.
Thanks.

 

[IFRs]

Kerosene does not have a vapor pressure high enough to warrant other than a standard floating cover inside a fixed-roof storage tank. As far as operating it with a higher flash point - how are you going to change the physical properties of kerosene and why would you want to? In the USA, see 40 CFR part 60 subpart kb and API 650 Annex H and API 2000. Inerting is typically only required if the internal floating roof tank does not have circulation vents, for kerosene there is no reason to not have circulation vents but the owner could specify such an arrangement. The flash point of kerosene is somewhere between 100 and 150 F and its vapor pressure is typically less than 1 psi

 

[fe2386]

Dear IFRs,
Thanks for your reply. Kerosene product has the specification of flash point minimum at 100oF (38oC), but this is a specific case that the kerosene is not sold as a product, but blended in diesel therefore the refinery economist asks to reduce the flash-point as low as diesel is still on-spec in maximizing diesel production.
The refinery is in asean region therefore the ambient is quite hot in the summer, the tank temperature is sometimes reached nearly 38oC.
Therefore,I am not sure that wheather or not we can reduce the flash-point of Kerosene below 38oC as the economist's request or the tank need to be inerted or modified before starting to reduce the flash-point.
I hope that you can give a proper recommendation, after receiving more information.
Thanks!

 

[IFRs]

Sir -
I always thought that the flash point of diesel was higher than that of kerosene - between 126 and 205 F. In any case, your question was if your fixed-roof tank could be operated with a floating roof without inerting. By USA EPA rule the tank may have a floating roof if the true vapor pressure is less than 11.1 psia, which yours does. By API 650 rule the internal floating roof tank needs to be interted if the tank does not have circulation vents per Annex H. The flash point does not enter into these conversations. As long as you have circulation vents you do not need inerting. If you do not install circulation vents then you need to inert the vapor space, or otherwise render it not flammable and of course provide pressure-vacuum vents. For example, gasoline has a flash point of -45 F and it is stored in huge numbers of fixed roof tanks with internal floating roofs with circulation vents and no inerting.