Advice on a peak blowdown rate required
Advice on a peak blowdown rate required
(OP)
Hi guys,
I need some advice.
I am doing some work with flarenet so I require some peak blowdown rates for my system. My blowdown valve is a globe valve (CV = 77). I am going to use hysys, but I am not sure about the vapour flow equation in Hysys, so I wonder if anyone knows a way to convert my CV into an equivalent area? Based on my values below, what are others getting as the peak blowdown rate?
These are my initial conditions:
100% vapour
system volume - 39.6 m3
pressure - 66.11 bara
temperature - 6.206 C
MW - 19.12
Z - 0.7764
Cp/CV - 1.184
viscosity - 0.01304
density - 70.12 kg/m3
I need some advice.
I am doing some work with flarenet so I require some peak blowdown rates for my system. My blowdown valve is a globe valve (CV = 77). I am going to use hysys, but I am not sure about the vapour flow equation in Hysys, so I wonder if anyone knows a way to convert my CV into an equivalent area? Based on my values below, what are others getting as the peak blowdown rate?
These are my initial conditions:
100% vapour
system volume - 39.6 m3
pressure - 66.11 bara
temperature - 6.206 C
MW - 19.12
Z - 0.7764
Cp/CV - 1.184
viscosity - 0.01304
density - 70.12 kg/m3





RE: Advice on a peak blowdown rate required
Good luck,
Latexman
Need help writing a question or understanding a reply? forum1529: Translation Assistance for Engineers
RE: Advice on a peak blowdown rate required
If instead you wish (as I would recommend) to take in account the heat exchanged then you need to simulate the blowdown process,
generally the procedures available in simulators (I use Prode Properties but I guess your software applies a similar code) consider a RO (instead of a CV) to control the flow, then you need to convert your CV to an equivalent area, this is not simple as for a control valve there are different parameters to consider,
I would suggest to calculate the critical flow (through your CV) at initial condition and find the RO area which produces an equivalent result.
RE: Advice on a peak blowdown rate required
RE: Advice on a peak blowdown rate required
K = 891d4/(CV)2
On page A-20 for sharp edge orifice an approximation is:
K ≅ (1 - B2)/(C2B4)
d = ID, inches
CV = gpm with 1 psi dP
B = orifice Beta
C = flow coefficient
These will get you started to "convert my CV into an equivalent area".
Good luck,
Latexman
Need help writing a question or understanding a reply? forum1529: Translation Assistance for Engineers