Vertical VS6 versus Horizontal - Lean Amine application Experience

[planck121]

Hello,
I am in the process of overseeing selection of a pump for a lean amine application in our plant. The vendor is proposing the use of VS6 type pump for this application due to issues with NPSH requirements on the Horizontal type pumps for simliar service. I am particular not comfortable with Vertical type pumps due to issues with maintenence and reliabilty that arise as as result of the vertical configuration (i.e shaft support on vertical pumps, shaft seals wear etc) which are not as common on horizontal pump configurations.

Would appreciate thoughts if anyone has had experience with VS6 types in amine service.

Thank You

 

[Pumpsonly]

If you have NPSH problem, what choices do you have..?

1) Raise the level in the suction tank..
2) Dig a pitch into the ground to lower your pump center line for the horizontal pump.
3) Use VS^6 pump.

VS6 pump may be slightly more trouble some in maintenance than horizontal in terms of access. A correctly sized and
installed vertical pump is as good as any horizontal pump in operation reliability.

 

[DubMac]

As Pumpsonly said; if you get a properly designed "canned vertical pump", this is the preferred method for lean amine and other low NPSH services. Make sure your pump vendors have plenty of API vertical canned pump experience; i.e. Sulzer, Flowserve, Afton, Goulds, etc....

With an enclosed lineshaft and properly sized discharge head (with possibly what is called a thrust-pot to support all axial thrust); this is a much, much easier design than horizontal from a Maintenance standpoint; especially the smaller your NPSHA gets. Horizontal will have to spin much slower to accomodate low NPSH (slower means larger & more expensive). Some will try to sell you the inducer configuration on horizontal. It can work, but there are many disaster stories over the years from improperly designed inducers.

 

[ApplicationENG]

Plank, how much npsh do you have - also what is the flow and head? I can tell you off hand if a pump vendor will be able to handle it.Pump vendors, i.e. goulds can create custom pumps for the application - this may be overkill. they can also supply an inducer to lower the NPSHr of the pump. Lastly, alot of vendors goulds also make low npsh impellers specifically for these applications.

i would seriously consider this because it allows you to stick with a horizontal configuration and avoid the burden of VS6 maintenance.