Experience in using Discflo pumps for multiphase fluids 1

[hianbotech]

We would like to know the experience in using disc pump technologies for multiphase application.

We want to use this kind of pumps in upstream application in our facilities, in order to send Oil, Gas and Water from the Wellheads to the production facilities. Several pumps will be connected to a common pipeline.

According with the theory this kind of pumps are good for viscous and abrasives fluids. However we do not know the behavior of the pump when a batch of gas suddenly flows through the pump. In that moment a drastic change of viscous occurs.

I would appreciate your collaboration in this issue.

Sincerely
Hianbo

 

[unclesyd]

We use them in pumping multiphase flows of many types with great success. We used them in immiscible materials where we didn't want to make an emulsion, a salt solution that would start to polymerizing if any heat was added, and a solution of organic acids that didn’t like centrifugal pumps .

I know of quite a few other installations that have worked out very well.

I would run your application by the people at:

http://www.discflo.com/

 

[KernOily]

My experience is the opposite. I have two - 75 hp 3600 rpm Discflo pumps in just this very service. On paper they appear to be a good fit for this application. However, reality is a different story, as is so often the case.

In my application, which is just like yours, the fluid is 80% w/c 13° API crude at 175° F and the pumps take suction out of a horizontal vessel and discharge into a pipeline for transfer to another plant about two miles away. We do this due to custody transfer and metering requirements and we pump through a wet LACT. We experience frequent seal failures and cavitation damage due to the gas slugs. Also, the controls in the vessel are iffy for several reasons beyond the scope of this discussion, so this causes the pumps to get hit with gas slugs from the vessel dome gas, unfortunately. These pumps are not cheap to repair either, especially in stainless, which mine are. We selected Discflo for this application to prevent shearing and further emulsification of the fluid.

I suggest you remove the gas in a separator or knockout of some type and deal with the gas separately prior to shipping the oil-water liquid phase. Then you can use regular centrifugal pumps (if you can tolerate the shear) or maybe a progressing cavity or a large slow-speed recip pump.

I realize that sometimes it is not possible to remove the gas ahead of time though - if that is your case then I would look at some other type of pump that is more tolerant of dry running and gas slugs - maybe a recip pump or one of those $$$ European multiphase pumps designed especially for the purpose. - Pete

Thanks!
Pete

 

[Karlando]

We tried to use Discflo pump in our slurry plant. If the viscosity, solids, flow and pressure were the same all the time => no problemos, but if changes in some parameters => no can do.
So we said adios to Discflo after 8 hours testing.

Best slurry in town

http://www.chemec.fi/

 

[hianbotech]

Thanks 74elsinore for your comments.

Actually we have already install several positive displacement pumps in our wellhead for multiphase fluids which have operated for several years. However we want to test with a disc pump in one of our wellheads in order to compare the operational cost and the performance of the new pump in the application.

The pump vendor told us that disc pumps will not compress gas, then when a gas pocket pass throught the pump the delta p through it will be lost and a backpressure in the discharge occurs, because this pumps will be connnected to a pipeline network. However the vendor assure that the seal will be protected with a api plan 5411 for this case.

In normal operation the rpm of the pumps will be adjusted in order to keep the suction pressure.

Additionally in the moment of the gas pocket pass in to the pump. The rpm will be reduce automatically until a fix value while the pump recovery the discharge pressure. However we do not have a reference of this protections and controls in other real aplications.

Thanks, Hianbo