Installing a Spill Back Flow

[cilacap]

I will install several new pumps as crude transfer pumps from storage tank to mixing tank. The pump will be operated in large various of capacity. The plant operating mode and availability of specified crude are reasons. Choosing pump specification to be difficult due to much different of capacity between maximum and minimum flow required. In planning I put maximum operating flow as pump rated capacity, but I am not sure that minimum operating flow able be fulfilled by pump as minimum continuous flow.

I make a plan to install spill back flow from discharge line back to storage tank or suction line in purpose to keep in order to pump work at least at minimum continuous flow when capacity required is lower and remain flow send back to storage tank or suction line.

Look at mention my planning; I need advices for some questions below;

1. Whatever does matter I have to consider for installing a spill back flow?
2. To install pipe line from discharge line to storage pump will spend many material, what effect to pump and fluid flow when back flow from spill back line entrance to suction line?

Thank you for your attention.

Ari Dwikoranto- Mechanical Engineering

 

[BigInch]

Extended periods of recirculation into the suction line at low flows may cause excessive heating, in which case you should consider recirculating back to the storage tank to provide cooling, primarily by mixing with cooler product in the tank.

Over-pressure control for the recycle line and upstream piping, as you could have full pump pressure potentially reaching to the suction line or to the storage tank. Check your pump's inlet pressure rating and other pressure limited components on the upstream side.

Method of controlling the recirculation flow, could be via an orifice plate or control valve (perhaps a Yarway valve). Disadvantage of an orifice plate for multiple crudes or products is it may be difficult to get a one-size-fits-all orifice diameter for all products and a relatively large and variable differential pressure as you start flow in a line, esp. with heavier crudes, and gradually build up flow, probably with associated reduction in discharge pressure. A control valve may be a better choice in that case.



BigInch-born in the trenches.

http://virtualpipeline.spaces.msn.com

 

[25362]

Ari, what is the reason for selecting all the parallel pumps with the maximum size ? Have you considered some of the pumps to be of a reduced capacity ? What about energy consumption ?