Milk of lime pumping

[Choco2000]

I´m about to design a milk of lime pump system, here´s what I propouse:

Slurry: 5% of lime 95% water (costumer data)
Flow: 150 gpm
Speed on pipes: above 7 fps
slope on pipes: above 2%
Closed circuit
Centrifugal pump
12 users in the system, all together consume 100 gpm of the milk (costumer data)

Main concern:
If we sudenly draw 100 gpm from the system the velocity will drop from 7 fps causing inlay and caking.

Should I increase the velocity moving more slurry in the loop?
Are my considerations ok?

Thanks for your help.

Adolfo Gómez
Ingeniero de proceso
AIL de la Laguna
Torreón, México

 

[rutherford703]

If this is a new system, you can reduce the piping size downstream of the 100 gpm take-off to increase the velocity inside the pipe. If this is an old system, you have to do whatever to maintain the slurry velocity above the deposit velocity including the circulation rate.

 

[Choco2000]

Thanks rutherford, is a new system, I ran some calculatios and I think I need a 400 gpm flow on a 4" pipe, so wen we pull out the 100 gpm the velocity in the pipe loop will drop from 11 fps to 8.31 fps, avoiding settling. I'm not very sure about the viscosity, I'm using 1 Cp on this mix, I can't find data on this, can you help me with it?

Regards

Adolfo Gómez
Ingeniero de proceso
AIL de la Laguna
Torreón, México

 

[bimr]

Viscosity is normally not a major concern. milk of lime has a low velocity, maybe 1- 10 cps.

The fluid velocity should be a minimum of 5 fps and should generally be in the 5-8 fps range. The velocity of 11 fps is too fast.

 

[Choco2000]

Thank you bimr, I'm going to run with 8 fps to see how much HP on the pumps I can cut.

Regards.



Adolfo Gómez
Ingeniero de proceso
AIL de la Laguna
Torreón, México