Crude Oil Control Valves 1

[jmalter]

I'm looking for vendors of control valves for a recirculation line for a crude oil pump station. The line is 4" and is from the pump discharge (1400 psi) to the pump suction (35 psi). Are some manufactures better for crude oil under these conditions? We are looking at the regular suppliers we use in plant (Fisher, Valtec) but I just want to make sure that pipeline is not a special application. Additionally, conpressed air is not available so we are looking at electric or electrohydraulic.

Any advise is most appreciated.

 

[d23]

jmalter:

I think Fisher makes electric controlled valves. If you can't find one there do a look-up on the SLB.com web site. I believe that Kim-ray (not sure of spelling) makes them too. All three companies are oil field suppliers.

Good Luck!

 

[spud1]

I think the valve you are looking for will need to be a multi-stage trimmed valve. Your application will be prone to serious cavitation due to the high pressure drop (1365 psid) - you will have to give the valve manufacturer the vapour pressure for the oil (assuming there is only one).

A multistage trim should reduce/eliminate the cavitation however you may need a "drag" style valve from CCI or Copes Vulcan's "Raven" - all of these are expensive.

Electric actuators are readily available from Auma, Rotork or Schiebel - any good valve manufacturer should be able to fit these and they are available EEx d/Flameproof.

Electro-hydraulic actuators tend to be somewhere in the region of 3 to 4 time more expensive than the electric units and need a resevoir or mains source of hydraulic fluid which can be messy & a pain to maintain - we recently had a fire in a CHP plant which looks as if it was caused by hydraulic fluid leaking from badly maintained hydraulic lines. Electro-hydraulics will give you a faster respons e than an electic actuator which is why they are used in anti-surge applications

 

[jmalter]

Thanks for the detailed reply.

Several vendors responded to our RFQ based on our data sheets and did not seem that concerned with the pressure drop. We stayed with the globe valves that have cavitation control and beleive we have 2 good quotes. The real test will be how they respond in action.

 

[spud1]

Thanks for the star...

Just a reminder - check the vendors used the vapour pressure you supplied in their calculations,assumptions are sometimes made by the sizing software which don't tie in with the data supplied by customers.

If they have they given you the cavitation index for the application (also known as Sigma) you can then check the trim they have offered against their published trim data to confirm its suitability.