Lime slurrying and pumping 1

[PeterAB]

I am making up to a 40 wt% lime solution in water by auger feeding 5 tph hydrated lime into a simple mixing tank. The pumps that move the slurry are don't reach their design capacity because of lumps and air entrained in the solution. Can anyone advice me on the most cost-effective means of alleviating this problem (introduce lime subsurface into mixing tank, install delumper, install trap and vent for air, use different type of pump)?

thanks,

PeterAB

 

[cub3bead]

Have you considered buying the 40% lime slurry directly from your supplier? Yes, you will be paying more for the freight but you will eliminate your mixing problem.

Many of the lime users along the Texas Gulf Coast have shifted to this because of the problems you describe and problems with getting the hydrated lime out of the storage bins due to our high humidity.

5 tph is an impressive amount of lime use. What are your doing with it?

 

[hacksaw]

how are you getting "air" in your pump suction?

could this be cavitation, formation of suction vortices in the tank, etc.?

Lime slakers/mixers require special designs in order to be successful. It is not usually just a matter of a screw feeder and a mixing tank...

 

[unclesyd]

I think you need to check this website out. We have pumped some pretty rough materials through these pumps.

http://www.discflo.com/index.html

 

[smckennz]

Hi Peter
you need a decent agitator in the tank which should be baffled, and shroud the pump suctions.
Our normal practice is to have an auger fed batch mixing tank (with agitator) and an agitated recirculion tank which feeds the users via a ring main. Feeding the lime in slowly prevents lumps.
The most important thing is to keep everything moving - stop anything and you are dead.

Cheers

Steve

 

[PeterAB]

Thanks to everyone who replied to my question about lime slurrying. Allow me to elaborate a little bit, in response to some of your questions. The lime is used in a flue gas desulfurization application. We're using hydrated lime - it has already been slaked. My understanding is that auger-feeding this into a mixing tank is standard practice for slurrying hydrated lime, which is easy to wet and should therefore not be a particularly difficult dispersion/ slurrying application. The problem arises from the fact that we want a 40wt% concentration. Dry lime floats on top of such a dense slurry, and when the mixer pulls it down it pulls air down with it. I don't know where I can buy such a high concentration as a slurry. Does anyone have experience with slurrying lime at this concentration?

PeterAB

 

[mariodupuis]

We make 40% lime slurry, to decrease viscosity of the slurry, we add a dispersant like naphthalenesulfonate polymer.

It should help you at a resonable cost.

 

[PeterAB]

mariodupuis:

Thanks for providing a fresh solution to the problem.

Could you advise who supplies the dispersant, and how much you need to add?

regards,

Peter AB.