Relief Valve Calculation on Vessel Jacket
Relief Valve Calculation on Vessel Jacket
(OP)
I'm calculating the relief valve requirement of a fire case for a water-filled jacket on a vessel. I'm planning to calculate the heat from the fire, calculate the vapor generation, and then convert it to the same volume of liquid (at relief pressure) since liquid will be pushed out the relief valve first, and should be the worst case. So the actual orifice calculation would be based on the liquid flow. The relief valve is on the piping coming out of the top of the jacket.
Are these fair assumptions? I've never done calculations on just the liquid filled jacket before. Any recommendations would be appreciated.
Thanks,
Tony
Are these fair assumptions? I've never done calculations on just the liquid filled jacket before. Any recommendations would be appreciated.
Thanks,
Tony





RE: Relief Valve Calculation on Vessel Jacket
RE: Relief Valve Calculation on Vessel Jacket
RE: Relief Valve Calculation on Vessel Jacket
J. Alton Cox
www.delucatest.com
RE: Relief Valve Calculation on Vessel Jacket
RE: Relief Valve Calculation on Vessel Jacket
This handbook may be of some help.
www.tyc
RE: Relief Valve Calculation on Vessel Jacket
In the pre-DIERS days one would calculate the relief area required for vapor relief (vapors calculated by heat input from fire). Then one would assume (or calculate) the liquid entrainment and calculate the area required for that flow. The two areas would be added and a generous factor multiplied in to account for choking by the two flows.
You might want to google DIERS to see whether you get any formulas for this case. I have not looked into the API RP 521 for a long time, but does DIERS not get a mention there?
RE: Relief Valve Calculation on Vessel Jacket
http://www.digitalsolutions.org/
J. Alton Cox
www.delucatest.com
RE: Relief Valve Calculation on Vessel Jacket
helps :)
1. Heat Absorbed From The fire
qin = 34,500 F(A^0.82) <------NFPA 58
2. Vapor Flow Rate
Qrv = qin / hfg
where;
qin = is the total heat absorbed (Btu/hr.),
F= (insulation factor)
A is the total surface area (ft^2)
Qrv is the gas discharge rate (kg/s)
qin is the total heat absorbed (kJ/s)
hfg is the latent heat of vaporization at release Temp.
Let me know if you need sizing calculations and for what type of flow.
Cheers