Lime slurry Viscosity.

[SlurryS]

I'm working on a design for a separating tank in a lime slaking system and have really hard time finding viscosity data that would make sense. I'm looking at nom 25% by wt lime slurry at 185F. I found a few topics here but most were closed so i had to start a new one. I appreciate all help.

Thanks,

 

[BigInch]

The problem is that there is no fixed viscosity for lime slurry. Viscosity varies with lime content and .... velocity.

Independent events are seldomly independent.

 

[SlurryS]

I was able to find older threads where this issue was brought up, but all are already closed and I don't know if posters still use the forum. One of them mentioned that he did lab test for similar slurry (% by w/t & temp) see thread 407-141690-Slurry pumping problems. Value quoted was 10cPs but ranges i found elsewhere where much highe (40-700 cPs).

 

[Artisi]

SlurryS:
Suggest you contact one of the major slurry pump manufacturers or their agent and ask the question. They have a wealth of experience and data at their finger tips.

OR

Have you tried your friend "google" seems there plenty of reference there for lime slurry viscosity.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[stanier]

I would do a number of analyses using different viscosities. Look at the resuts and see what that impacts on your system. You will probably use a positive displcaement pump such as a progressive cavity pump, in any event, so head is only a concern for motor power.

“The beautiful thing about learning is that no one can take it away from you.”
---B.B. King

http://waterhammer.hopout.com.au/

 

[SlurryS]

Artisi, thank you for the tips, yes I 'googled' this far too many times before posting my question here, and assume most of other users here do the same. I also tried calling some pump mfrs but they don't seem to have anything exact. For now I'm using a ballpark figure of ~100cPs and if the lab tests we are planning to do will give me something different, I'll post the numbers here.

 

[Mech85]

SlurryS,

The viscosity of hydroxide slurry can vary greatly from lime to lime as well as process conditions. Certain changes in the hydration conditions or impurities in the lime will increase the viscosity of the slurry, thus affecting settling time.

Often times, the viscosity increases at slaking temperatures of 80°C (~176 F) and above. The relationship of viscosity, particle size, specific surface and settling rate is not currently completely researched. In general, it is presumed that the higher viscosity means a smaller particle size of hydrate, greater specific surface and slower settling rate. Variations of the viscosity of hydrated lime slurry have been reported between a range of 45-700 centipoise - so lab testing is definitely worthwhile for your specific application.

 

[SlurryS]

Thanks Mech85. I hope lab test planned will help and i'll be able to post something for others to use.

 

[Ktracid]

We simplify it and treat milk of lime as any other slurry. There are some curves that indicate the variations of slurry viscosity with respect to the volumetric solid percentage and size of solid particles. If you let me know your conditions, I can try to get you an estimate. Unfortunately, the curves that we use do not have temperature effects incorporated in it.