Ball Valves Comparison with Triple Offset Butterfly Valves for Crude Oil Tank farm Area 2

[SabirPakistani]

Can i use triple offset butterfly valves in place of ball valves. Line sizes range 24" to 56". Pressure rating 150# to 600#. Service is crude oil maximum operating temperature 120DegC. Please guide me i need experts opinions.

 

[gerhardl]

Crude oil is not in itself an exact description of what could possibly gothrough the valves. Crude oil is often rests, residues and an end-product-mix from refineries. You could well face vastly different fluids, gases and additives/residues at pressures and temperatures given.

I believe, as it is very often, that here is no clear yes/no answer to your question. Requirements from different sources will have to be taken into consideration: (end-user, authorities, local and branch standards and requirements, fire-safe requirements, cleaning and closing down requirements (pigging? blocking? venting?), economy, replacement availabillity, company standards, safety standards, cost/time considerations, actuator cost and operation etc, etc). It is easy to oversee requirement and be stuck with responsibillity for this.

Also, most times, this kind of questions stems from considering only one of the many aspects. Most often because 'somone' wants to earn or save some money.

The control question you should ask yourself: is this the best solution for all parties involved?

 

[SabirPakistani]

gerhardl,
Thanks for your nice guidance for me, you are right we can not immediately say butterfly valves can replace ball valves unless we have strong justification and proven records for similar kind of service.
I will collect more data then i will raise further querries.
Sabir

 

[TransMech]

I agree with Gerhardl, for isolation(no DBB requirement), throttling and sacrificial purpose, maybe TOV is good choice.

 

[NGiLuzzu]

I agree with gerhardl me too: the service conditions (in particular the fluid nature and relevant concerns) should be better detailed in order to allow giving good advice.

However, in general terms, I would guess that if ball valves are suitable for that, triple offset metal (torque) seated valves may work as well (or even better…?).

Of course You should start asking the most specialized and well known Manufacturers.
See, for instance:

- thread408-183795;
- thread408-126483;
- thread408-135872;
- thread408-190488;
- thread408-145006;
- thread408-141966;​

within this Forum.


Hope this helps,
’NGL

 

[viki100]

Hello,

http://solentpratt.cwfc.com/products/PDFs/Double-Block_Bleed-TOSV.pdf

Viki

 

[Ripz]

Ball valves throttle, butterfly valves don't.

Once you can find a suitably designed butterfly valve for the application, just ask your operators if they can operate without the ability to throttle.

 

[NGiLuzzu]

Ripz,
I guess Your statement about butterfly (and ball) valves must not be intended in general and absolute terms; it depends on how accurate and in which range the flow control is required…: do I understand right?
As far as I know, for example, many triple offset valves have a flow characteristic in the middle between the “equal percentage” and the “linear” types, hence a good rangeability as long as they’re far enough from the completely closed (0°) and completely open (90°) positions; moreover I believe You’ll meet less inertia, friction losses and risks of jamming when You try to rotate a disc in respect to a ball...! ;-)

In any case, well-established Manufacturers may provide calculation software enabling You to predict the opening angle or the flow rate (as well as the noise level) for any given set of service conditions, so that You can understand, case by case, when a certain valve may be suitable or not…


SabirPakistani,
of course well-established Manufacturers may provide “proven records for similar kind of service” (i.e. reference lists) as well, including flow control cases, if applicable.