Flare piping design 2

[Petroleo]

Hello All,

Please do you know how to calculate the mean metal temperature? I need it to determine the design temperature of the flare piping dowstream of the BDV/RO in case of depressurisation.

Thanks in advance,
Petroleo

 

[Latexman]

This thread, thread124-202829 , is on topic. I'm sure if you use Google or the Google search function on this web site, you can find much more good adviced.

Good luck,
Latexman

 

[Petroleo]

Latexman,

I have read the posts and I confirmed this is a complex system. You mentioned that "the latent heat in the metal will transfer from metal to fluid". Is that involved in the calculation of the metal mean temperature? Because I am calculating the internal wall temperature (gas inside, air outside)from:
Tw= T + DTi = -51C (free convection) or -18C (forced convection)in which T is the av fluid temp
DTi = (1/hi)/(1/hi+Di/Doho)*DT
hi using Colburn = 72.4 W/m2K ho (free convection) = 6.21 W/m2K gives an Upipe = 6 W/m2K
ho (forced convection) = 135.7 W/m2K gives an Upipe = 40 W/m2K

And external wall temperature by:
Tfilm = 1/2( Tw + Tam )= -7.5C

As you see these eq give a DTw = 43C (free convection) or 10C (forced convection). How can I check if these results are reasonable?

Thanks in advance,
Petroleo

 

[MortenA]

You should try to get a copy of the article "Material selection for low temperature application" from hydracarbon processing july 2004.

This article also describes amethode for determing metal temperature and a material selection route chart.

Best regards

Morten