Problem on Slurry Pump Caused by Flocculated issue? 1

[imanstarr]

Hi everyone,

I am so happy to found this forum, i am very confusing with the problem that is happen currently.

I have slurry pump case, driven by electric motor. Pumping Slurry from Settling Pond to final Sump.

Can flocculated in Slurry (in the Settling Pond) effect to higher load in the slurry pump operation?

What effect to the slurry pump from flocculated fluid condition?

If it is Yes, how can be? I will very appreciate if anyone can explain it to me.



Thankyou guys

 

[bimr]

Have you measured the % dry solids contents of the fluid that you are pumping?

 

[LittleInch]

Higher flowrate?

We need a bit more data here such as:

Pump data / curve,

Fluid data,

Higher load? - Measured by? Readings?

What can you measure? volts, amps, pressure? Flow?



Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[imanstarr]

Guys thanks for replying my thread. I really appreciate it.

Pump curve.

https://files.engineering.com/getfi...4031-81f1-8b1bd4725108&file=curve_EL1204B.PNG

Pump Specs

https://files.engineering.com/getfi...9316-d2c4baccbb22&file=Pump_Specs_EL1204B.PNG

Requirement:
Flow Rate = 300 m3/hr - 400 m3/hr
SG = 1.2 - 1.3
TDH = 30-37 m

Slurry Test:
Particle Size = 55,27 nm
Viscosity = 135,6 cP
Specific Gravity = 1,15 g/ml
PH = 4,75
Solid Content = 146.672 ppm

The point of my question is, how can flocculated condition can make the pump load is higher.(please find above for slurry test viscosity)
how to calculate it?

 

[Artisi]

The data only tells the pump capability and the estimated slurry condition, it does not tell what the actually thru'put of the pump in terms of flow and developed head.
Assuming the slurry is as described and you are saying the power absorbed is higher than anticipated, it seems that the flow rate is higher than expected.
Or, the slurry solids content is much higher meaning a higher density and SG.

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.)

 

[LittleInch]

Is your slurry test to a ridiculous level of decimal places the actual slurry or what the pump was designed for?

You haven't said what this "higher load" refers to.

Is this a change of slurry?

From what i can find flocculated slurry will settle out more solid material and will therefore be denser if you're pumping form the bottom of the pond.

Give us something to work with here and not drip feeding information

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[bimr]

What is causing the viscosity? What is the mineral in the solids?

 

[imanstarr]

Back again guys,

FYI this is application in mining project.

LittleInch
Is your slurry test to a ridiculous level of decimal places the actual slurry or what the pump was designed for?
--> it is actual slurry
You haven't said what this "higher load" refers to.
--> our dealer told it to us, and they recommend that pump for the requirement that i mention it above.
and then, several problem arise, so they said the problem caused by Flocculant.
that is why i need relationship between flocculation and pump performance.
If there is calculation to explain it will be good.

Artisi
SG requirement = 1.3, and the dealer has agreed at the beginning.
When there is some problem happen, and pump durability proved to be not good, so they are concerned about flocculant
And i still don't get the relationship between pump performance with flocculant.
please info what data you need so that it can help me.

bimr
What is causing the viscosity? What is the mineral in the solids?
--> i don't know actually, but they (dealer) say it is caused by flocculant.

 

[Artisi]

Seems you have an application problem which won't be sorted out by back and forth chit chat, you need someone who understands pumps and their application at the installation for a proper analysis of the operation.

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.)

 

[Artisi]

Pump brand and some detail might also help.

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.)

 

[LittleInch]

imanstarr,

You're not helping us here.

So can you describe:
What is the condition of the Slurry in the settling pond? Is it after the flocculation is added or during? As you should know flocculation will "flocculate" the slurry into a more dense material and a watery layer on top.
Given than flocculants help bind the slurry together then increased viscosity would seem likely to occur versus the untreated slurry.

So is your slurry analysis above before or after flocculation?

"and then, several problem arise," - What exactly are these problems that you refer to? You haven't told us anything about what the "higher load" or "problems" actually are.

That viscosity looks really quite high, but your pump data has no mention of viscosity.
What viscosity was assumed or used in the design / put into the pump data sheet given to the vendor?
Density is important for pumps and power, but viscosity will impact the head required to flow a certain flow.

What is your downstream system and what is your system curve? i.e. what head do you need to generate a certain flowrate??

What keeps the slurry material in suspension in your pond?

Remember we only know what you tell us or describe or draw. We can't see your system or data.


Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[moltenmetal]

Why do you add a flocculant? You add it to increase the % solids of the underflow of a clarifier or thickener to make it more effective at its job, which fundamentally is separating solids from liquids, producing a slurry of solid in the (hopefully) minimum amount of liquid necessary for transport.

If you start without a flocculant, or if you were previously using a poor flocculant, the clarifier/thickener will work less well, and fewer solids will settle to the bottom and more will leave from the top with what is supposed to be clear liquid.

If you then change to a proper, better flocculant, properly mixed etc., you will end up with very clear effluent from the top- a nice solution free of solids, and all the solids falling to the bottom where they have to be pumped out. But the whole idea there is that if you do a better job of settling the solids, you can remove the solids at a lower volumetric flowrate, i.e. at a higher % solids.

If you are achieving such a high % solids that your pump can't pump them any more, you have two choices:

1) A different design of pump, say an air diaphragm or peristaltic or perhaps progressive cavity (often a poor choice) pump which can handle your more viscous slurry better than what you have, or

2) You need to pump at a higher flowrate, so the % solids of the bottom stream drops and you take more liquid with your underflow.

If you are operating the pump based on a "sludge level" at the bottom of the clarifier, you may need to change your strategy if you want to keep the same pump.

 

[TenPenny]

With a viscosity in that range, your correction factors will be somewhere around .98 for head, .97 for flow, and about .85 for efficiency, so your power draw will be significantly higher than expected, if that was not factored in.

My recommendation is to get your vendor to supply you with corrected curves based on the SG and viscosity that you actually have.

 

[Nutzman]

Good day iamastarr,

As per the many posts above, you mention "higher load"?
Looking at the available data I make the following calculations:

Q = 300 m^3/h
H = 37m
SG = 1.3 (worst case scenario)
Pump eff = 51%
Power absorbed = 77.09 kW

Second duty:
Q = 400 m^3/h
H = 30m
SG = 1.3 (worst case scenario)
Pump eff = 55%
Power absorbed = 77.28 kW

Looking at the power curve (supplied), the curve is based on CLEAR WATER performance and NOT slurry. It's not possible (it is but very expensive)to publish a curve for every change of SG.

Flocculation of product, in my experience has never contributed to "higher load" in terms of power consumption. But SG on the other hand contributes.