Hydrated Lime Slurry Pumping 1

[Pulpboy]

Does anyone have any reference material for pumping of lime slurries. Things like:

1) Line velocities (I've read around 4 to 7ft/s.)

2) Densities for pumping

3) Properties of lime slurries at various densities (viscosity etc)

Does anyone have any actual testing performed that can be referenced?

I'm trying to better our current system which is plagued with downtime / scaling / dosage problems / leaks etc.

I would like to put in a volumetric feeder to control dosing / density better (versus our rotary feeder that sometimes dumps a slug sometimes doesn't and our density meter which scales up so bad readings are tenuous at best between acid washes.) I was looking at the ktron Bulk solids pump.. any experience?

Standardize valving to self cleaning / hardened ball valves and pinch valves.

Make sure slurry tanks/agitators are mixing well.

Install diffent pumps besides our centrifical pumps (discflo / peristaltic... other?)

And last but not least piping may need to be changed since we use sulfamic acid to clean and sometimes Rydlyme. Right now we have 316L and either teflon or polypropylene but I can't remeber.

Any other suggestions?

 

[siretb]

Velocities
0.5 - 2 m/s 0.5 is a bit low
Densities: Well, this depends on what you want to do, processwise: above 19% wt the viscosity increases al lot
I like the 12-15% range (as Ca(OH)2 weight percent)
1.093 specific gravity is about 15%wt, but the slope of the curve is steep 1.105 sg is about 17%wt

Lines should be sloped, and a good idea is to have a service loop, in which you circulate the lime milk at a high enough velocity to avoid settling, and draw from this loop what you need.
Consider HCl for cleaning
Scaling: well this is much related to the water quality and the temperature level tou operate at. At any rate you need sweet enough water.
Hope this helps

 

[cub3bead]

Browse around Chemical Lime Company's web page, you will find much of what you seek there.

 

[Pump2005]

At my plant we run direct from pump to sedimentation tank. We also added a secondary manual flush line to our pumps that had an automatic flush. Main thing we did was upgrade to a peristaltic pump with a vfd. Our slurry(50lbs:100gal/water)is mixed 24/7 regardless if the plant is online or not.

 

[orenda1168]

There are also chemical suspension/dispersion/stabilization mechanisms that will substantially inhibit sedimentation of Ca(OH)2, and with routine pumping and recirculation, provide a more uniform mix.

Orenda