Floating roof tank

[HDIMR]

Hi,

I am doing some design of atm. storage tank for Hexene. Part of that is roof type selection? Is there any max vapor pressure limitation of the stored liquid for floating roof case?

Appreciate any help/guidance on this matter.

Regards,

 

[IFRs]

In the USA, the EPA limits the vapor pressure for a floating roof tank to 76.6 Pascals. See 40 CFR 60 subpart KB or WW

 

[HDIMR]

IFRs,

Thanks for your valuable reply.

Do you know what is the basis of such value.Is it max pressure the roof could withstand or is eniviromental/emmission concern?

Thanks in advance.

 

[IFRs]

I don't know the basis for the cutoff but I can guess:

If the liquid is boiling, a floating roof is no good and maybe the EPA figured a factor of safety would be good. Also, the losses through the IFR are vapor pressure dependent, so at higher vapor pressures there would be more losses and mabye at those vapor pressures the EPA judged an IFR to be too inefficient.

As far as maximum pressure an IFR can stand, I have seen aluminum IFRs lifted off their supports by pressure underneath with no damage whatsoever. In fact, I have deliberatly done this several times for maintenance or repairs.