Pump Selection: low flow, high head, and highly abrasive 6

[brs766]

I currently work with a 30% (wt) Alumina (Al2O3) slurry that has a relative hardness of 9 (mohs). This application is shear sensitive (and non-newtonian, shear thinning to be precise) and because of that we are using a DiscFlo pump. Unfortunately our system design leads to an unsustainable operating point for our DiscFlo pump.

The process conditions are as follows: 200-250 ft of head and 20-25 GPM. This produces an operating point on the far left hand side of the curve which causes a lot of internal re-circulation (greatly accelerating the wear mechanism). In fact, our pump discpack (DiscFlo equivalent to an impeller) lasts 2-3 months.

I am trying to determine what type of pump would be best for this application. I have some general ideas in mind (piston/ plunger pump, triplex piston pump - to eliminate dampening, and flexible membrane pumps - piston diaphragm). I am staying away from anything that isn't a positive displacement pump (because imparting velocity on shear sensitive fluid does not seem like the best route and the flow conditions provide a very challenging hurdle for a centrifugal pumps). I had considered using two Centrifugal or DiscFlo pumps in series but I figured that would cost a lot of money and give me two failure points.

The vendors I have reached out to are CAT Pumps, Hydra-Cell, and Abel. My question is, do you think these are the proper pumps for this application?

Please let me know if I left out any pertinent information, I will be looking forward to your responses.

Thank you so much!

Ben

 

[gempump]

Hi Ben, may I ask what type of pumps did you select?

Heavy-Duty Centrifugal Slurry Pump Manufacturer

http://www.gempump.com

 

[Artisi]

Hopefully not something from a pirate pump supplier.

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.)

 

[gempump]

Artisi,
I am a service support engineer,hopefully I came to the right place.

Heavy-Duty Centrifugal Slurry Pump Manufacturer

http://www.gempump.com

 

[Artisi]

Gempump- yes, the right place to give good technical advise only.


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.)

 

[brs766]

I am very sorry for the late response but we decided on trying this pump (

http://www.vogelsangusa.com/products/rotary-lobe-pumps/?L=8)

(hopefully I didn't violate any terms by posting the website, I assure you I am not close with Vogelsang, they offer the trial to anyone willing to accept it). We did a lot of research and found some case studies from them that aligned with our product. They also offered a 90 day trial to see if the pump lives up to our standards. We are awaiting delivery on this trial but I will let you all know how it turns out!

Again, thank you all for the great amount of help.

Regards,
Ben

 

[itdepends]

I'd lay money on the pump failing very quickly. I've used that style of pumps on low flow/high head, abrasive slurries and they suffer from excessive wear between the lobes and the front face plate and the tips of the lobes themselves. As they are low rpm positive displacement pump they rely on close tolerances to avoid internal recirculation.

I hope you're using rubber or hardened lobes- you might get a week out of a set if you're lucky. We lost pump performance in a matter of days.

Best of luck.

Daniel


As a chem eng/metallurgist the first part of any answer I give starts with "It Depends"

 

[georgeverghese]

Energy efficiency is not good, but a blowcase might also be worth a try if you feel like throwing the towel in on this, if you've got compressed air to spare?

 

[SNORGY]

But for the fact it's a slurry service, I could readily accept the blow case idea. However, all those solids might chew up the associated valves in no time. So, if one was to go down that path, I suggest (1) no modulating valves and (2) get all of them as close to full port as you can get. If the push gas is plant air like instrument air, and you wash out the blow case dump valve, be prepared for the potential of an unwanted plant ESD.

 

[moltenmetal]

Nonsettling slurry is good in a blow case, with something like pinch or diaphragm valves (all rubber wetted parts) as the switch-over valves- but in most cases you'd be better off with an air double diaphragm pump. You know the check valves are going to fail, eventually, but it's a PM deal.

I'm not hopeful for the lobe pump- hope you'll keep us apprised.

 

[georgeverghese]

Something like a sparger pipe in the blowcase liquid section may help to keep this slurry from settling during the fill-pressurisation routine. May be run the sparger for a 30seconds or so before the dump valve opens(just before the end of the pressurisation step)?