High Pressure/Flow Acidic Slurry
High Pressure/Flow Acidic Slurry
(OP)
I need to pump a 3.5% sulfuric acid / 20% wood pulp slurry. Flow needs to be variable from 1 GPM to 800 GPM and will be injected into a reactor at 400 PSI. Temperature of the slurry is 140 degrees F.
We are currently using a Seepex progressive cavity pump for 1 GPM injection but we need to increase flow and I have concerns about the reliability of these types of pumps.
Anyone have any suggestions?
We are currently using a Seepex progressive cavity pump for 1 GPM injection but we need to increase flow and I have concerns about the reliability of these types of pumps.
Anyone have any suggestions?





RE: High Pressure/Flow Acidic Slurry
Are you currently pumping this 20% slurry at 400PSI?
RE: High Pressure/Flow Acidic Slurry
There are patented and proprietary/trade secret devices to do this job. And they're not simple progressive cavity pumps...
Why are you mixing the acid with the pulp before feeding it?
RE: High Pressure/Flow Acidic Slurry
Artisi, we used a progressive cavity pump with a suction feed hopper, bridge breaker and screw conveyor to force the pumpage into the suction.
RE: High Pressure/Flow Acidic Slurry
RE: High Pressure/Flow Acidic Slurry
Have you had any problems with the small pump you are using now?
Are you planning on using 1 pump or multiple for the 800 gpm?
RE: High Pressure/Flow Acidic Slurry
We are pretty sure it will have to be a multipump system due to the turndown.
RE: High Pressure/Flow Acidic Slurry
Explain what you mean by "the flow has to be variable between 1 and 800 gpm". If you mean "the same single pump has to be capable of discharging this stuff at 1 gpm or 800 gpm", you're tilting at windmills. That's an unrealistic expectation of turn-down capacity for a water pump, much less one pumping pulp.
RE: High Pressure/Flow Acidic Slurry
Initially I was thinking of a four or five pump system, with an additional "jockey pump". However this brings me back to my original question, is there a better way to do it than with a pc pump? Multiple 100-200 GPM pc pumps with teflon stators is not my ideal installation.
RE: High Pressure/Flow Acidic Slurry
Real PD pumps are limited to about 10-20:1 on speed and about 10:1 on stroke, even when pumping clean fluids. Your progressive cavity unit has no stroke control, hence its practical turn-down limit is about 10-20:1 on speed- even if back-leakage isn't an issue.
And it will be...especially if teflon is your only stator option.
You need to get real about your capacity range. Realistically you're not talking about five pumps: even at 100:1, you're looking at eight pumps...
As to alternatives to your Seepex unit, aside from calling one of the people who have (apparently) already patented feeders for this purpose, unfortunately I'm short on suggestions! I have absolutely no idea how well (or poorly, or how long) these units work. But you're right to ask, as it never hurts.
With respect, I suggest you may be thinking about this the wrong way: you're thinking this is a pump selection exercise when it's really a process development exercise. I do wish you the best of luck with it.
RE: High Pressure/Flow Acidic Slurry
To be honest I haven't run through the numbers on the number of pumps in the multipump system. It's a non issue. We can add as many as needed. I am more concerned about the pump design at this point.
And the people that have patented this type of pump that I should contact, I guess that completely answers my original question (almost!). Thanks to you I now know they exist. On to the next step, who are these people and how do I contact them? :)
RE: High Pressure/Flow Acidic Slurry
RE: High Pressure/Flow Acidic Slurry
RE: High Pressure/Flow Acidic Slurry
A couple of hots in the dark for you to consider - concrete placement pump - well drillers mud pump.
RE: High Pressure/Flow Acidic Slurry
I was also thinking about contacting some oil & gas gurus.
RE: High Pressure/Flow Acidic Slurry
Mark Hutton
RE: High Pressure/Flow Acidic Slurry
I'm not in that business, but either
http://www.sunopta.com/bioprocess/index.aspx
or
http://www.iogen.ca/
might be worth a try.
Again, best of luck to you.
RE: High Pressure/Flow Acidic Slurry
I just realized that I misled you earlier. This is not a cellulostic ethanol application. The nail on the head comment referred to the "There are patented and proprietary/trade secret devices to do this job. And they're not simple progressive cavity pumps...", as in, that is exactly what I am looking for.
What we are trying to do, referring to the process, has never been done before. I was hoping however, that the pump application, or something similar to it, had been done before.
RE: High Pressure/Flow Acidic Slurry
It'd be a tough job to make a concrete pump suitable for dilute acid at 140 F. But that might be a good option. 800 gpm's a fairly large flow, though, and against 400 psig- you're doing a LOT of mechanical work. Is energy efficiency a secondary consideration at this point?
Can you feed the pulp separately from the dilute acid using a lock-hopper arrangement, then mix them under pressure?
RE: High Pressure/Flow Acidic Slurry
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RE: High Pressure/Flow Acidic Slurry
Check out Halliburtons HT400 recip, Dowell schlumberger and Calder. All used in the oilfield to pump a variety of slurries ,cement,acid fracturing slurries etc. Use a VFD drive for best control.
Offshore Engineering&Design
RE: High Pressure/Flow Acidic Slurry
RE: High Pressure/Flow Acidic Slurry
The Munsch centrifugal pump of solid HDPE casing would be right at its maximum temperature limit and could withstand the corrosion of the weak acid.
The Wirth diaphragm pumps have some very large sizes in mining slurry applications and could deliver the 400 psig. You would need to explore what materials they could offer for the weak acid service.