9 replies to this topic

[Dmitry]

Hello all,
I have a choke valve on wellhead, then pipeline from well to EPF. I need to calculate:

1. pressure drop on choke
2. pressure drop in pipe
3. diameter of this choke valve
I have pressure, flow, temperature upstream choke I know the pressure downstream this choke (in end point). I use Hysys steady state V 7.3 for it.

Pressure upstream choke valve 150 barg
Pressure on EPF (stream OUT) should be 35 barg.
Temperature upstream choke valve +40 C
Flow - 100 000 sm3/day
Pipeline - shc 80, 4" pipe, new pipe, without any isolation
Lenght - 1200 m. with out elevation change
Belowground - 1.2 m. Temperature ambient 0 C.


Components: mol fractions
Methane - 0.8
Ethane - 0.1
Propane - 0.02
Butane - 0.03
H2O- 0.05

Total - 1

My sketch in attaced file. Please help

Attached Files

•  Choke valve.jpg   30.31KB   110 downloads

[mohds23]

Dear Dmitry,

Required pressure at choke valve outlet will be = pressure drop in well flow line between choke valve and EPF at 0.1 MMScmd + Required pressure at inlet of EPF.

Understanding the problem is very important before you proceed to simulate.

Regards,
Mohd

[Dmitry]

Dear Mohn,

Yes, you are rigth!
Required pressure at inlet of EPF - 30 bar.
I can calciulate pressure drop in well flow line between choke valve and EPF at 0.1 MMScm
Then 30 bar plus calculated value = pressure downstream my choke. Then I need to find size of my choke. How cam I do it with Hysys?

Regards,
Dmitry

[mohds23]

I understand you want to size this valve for datasheet preparation.

Since choke valves are specially designed valves with multi openings, the best way to get required size of these valves is to contact supplier.

Of course, you cannot size these valves in HYSYS.

Regards,
Mohd

[Dmitry]

Hello Mohn,

Double click at valve - rating, and there is a button in Size valve. It's for valve sizing? or no? Why I ca not size the valve size in Hysys?

Regards,
Dmitry

[marchem]

a) you do not need a process simulator to size a control valve, in many cases the utilize of vendor's software (Masoneilan, Fisher etc.) is preferable since it keeps in account the correct valve parameters as fd,fl etc. which are important for both sizing and noise prediction (see Isa 75.01 ISO etc.)
you may use a process simulator to simulate the behaviour of a control valve (usually as adiabatic flash operation) and calculate properties of fluid at inlet and outlet of valve, of course any tool able to solve a flash operation can do this work, for example I prefer to use Excel with a specific library (Prode Properties) which sizes also the valve, but if you use HYSYS to model the plant that is automatic.
c) A choke valve (usually) works at critical flow, in a common design a piston moving in a cage opens several holes and the gas flows at critical condition, to size that valve you need experience, tools as CFD and specific tests, better to ask the manufacturer

Edited by marchem, 20 March 2012 - 02:33 AM.

[Dmitry]

Ok, and if I want to calculate RO, how can I do it with Hysys?

[karthik-process]

You can simulate the effects of an orifice by adding a fitting to a Pipe Segment. One option is to first add a Pipe as a Segment in the Pipe Segment Unit Operation (Pipe Segment Property View, Rating tab, Sizing page), then to add a fitting (e.g. Diaphragm Valve Open). You can then change the VHFactor (View Segment) to a K value representing your orifice. The most important part is then to provide HYSYS a proper value for K - the pipe fitting factor.

Good reference is "Flow of Fluids Through Valves, Fittings and Pipe" from CRANE.

[Shivshankar]

Dmitry,

I hope this following PDF will help you surely.I have one small request to you, whenever you put your question please uplaod all adequate information in the form of calculation worked copy attached, so that members on forum can guide you in proper way.

FInd attachment.

Regards
Shivshankar

Attached Files

•  Choke sizing.pdf   179.35KB   669 downloads

[Dmitry]

Thanks for information and advices,

Regards,
Dmitry