It really depends on the overall process. I assumed that as he is controlling upstream pressure, that it is controlling a vessel pressure (HP separator, free water KO, amine or glycol contactor, etc).
Daniel
Process Engineer
Rio de Janeiro - Brazil
Guys,
The capacity control IS the throttle valve. There is no variable speed here.
JustSomeRoark,
Do you already have the compressor selected? If so then it is easier because you already know what suction pressure the compressor must have to develop the discharge pressure that I assume is...
CO2 and N2 are not the exact same as design but have not varied wildly. They are the same for all machines though and this over-performance is only observed for this particular one. Don't think this is it!
Daniel
Process Engineer
Rio de Janeiro - Brazil
Im calculating the flow rigorously through the orifice plate dP. Everything is corrected, yes.
It is around 4% of the total poly head...a small number, yes. Still, the difference in potential flow (at same suction and discharge pressure) is pretty much an additional oil well, if looking this in...
"You mean 5kg/kgmole heavier."
Yes, sorry for the brainfart.
"Presume you're observing the derived polytropic head actually developed on this 2nd stage at this speed and flow is greater than that predicted on the poly. head - flow curve ?"
Exactly. For this particular stage I'm computing...
Hi everyone,
I’ve been comparing my compressors with the expected performance curves supplied by the OEM (I have multiple MW curves) and things are going well, where I often see a degradation on the compressor both on a polytropic head basis as well as on a polytropic efficiency, as expected...
The HEX are heaters, so the fluid will open a vapor phase nevertheless and now the valve has to handle two phase flow anyway.
Daniel
Process Engineer
Rio de Janeiro - Brazil
Guys, come on..
For this scenario, Option A is the most common. All my 3 FPSO's have this configuration for the first separator going into the second. No problem whatsoever, just design the entire system (valve, HEX) accordingly.
We often put the level control kinda like option B when we are...
Latexman,
I'm getting the blank page from your link too. Try uploading it again.
Kevin,
Not enough info to answer this question. Is the upstream conditions held constant or is this a depressuring problem?
Daniel
Process Engineer
Rio de Janeiro - Brazil
As a brazilian, I have not seen U-Stamp requirements on any pressure vessel sold here in Brazil. NR-13 would be applicable though.
Best regards,
Daniel
Process Engineer
Rio de Janeiro - Brazil
Just think of the equation:
Stagnation pressure = Static Pressure + Dynamic Pressure
When you lose pressure/energy due to friction, you are decreasing the overall stagnation pressure. Stagnation Pressure After = Stagnation Pressure Before - Friction Loss.
If you slow down the fluid in a...
I can't say why the software is not calculating the pressure drop through the tee. But, a straight flow through a tee is pretty much a straight pipe.
I'll refrain from trying to explain what the software is doing because I don't work for AFT. Maybe they can assist you through their support...
To each their own, I guess.
You can find Petrobras public standards here:
https://canalfornecedor.petrobras.com.br/en/regras-de-contratacao/standardization-catalog/
N-76 is their specs.
Daniel
Process Engineer
Rio de Janeiro - Brazil
Pavan,
B31.1 is for power piping, so usually applicable to thermo power plants.
Nothing in your process suggests that this is not a process piping - therefore B31.3.
If there is no pipe spec in your company, then suggest you employ a piping engineer to develop one for your. Or, use an...
Is your system really designed per B31.1 instead of B31.3?
Don't your company have an existing pipe spec where you can see the thickness for the 3" pipe in this service? I'd suggest sticking to that.
Daniel
Process Engineer
Rio de Janeiro - Brazil
Heat loss through a pipe is an effect of convection inside the pipe, conduction through insulation and convection through air. I've in the past compared Arrow's results to other software and found that in overall it is a good calculation.
I have never used a polytropic approximation for...
Keith, just to add to my previous post, *I* usually prefer a control valve controlled through a control loop with a PIT, but that obviously require more instrumentation which I don't know if it is really necessary to your system.
I'd set up the pressure on the header to be whichever the...
I'm sure the other guys will suggest something better, but you can maybe just employ a simple auto-operated pressure control valve with its pressure control on the intake.
Spirax, Emerson, Masoneilan and all the other control valve suppliers will probably have something that can work in this...
