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Conclusions
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This article is not finished yet. It will be completed soon.
We will discuss:
- what you do with these curves,
- how you design the SX-pumpers,
- how you can zoom in on the actual full-scale design without worrying about
scale-up rules using CFD,
- how to troubleshoot existing SX-circuits,
- how to know if the upper auxiliary impeller is doing its job,
- how to determine flow restrictions,
- how to optimize the design of the pumper's blades,
- how to know if your vendor met its guarantee obligations,
- how to know if you specified the right parameters for the design,
- how to measure your system head,
- how to make simple changes that will decrease the head requirements of
your system and make your system hydraulically efficient,
- how to reduce the power needed and increase flow rate (production).
Conclusions
- Scale-up of pumper mixers has been demonstrated
using dimensionless numbers
- You need to determine H, Q, P on any scale to create
your own head-flow-power curves
- This approach takes the guess work out of sizing the
pumper mixers
- Operating conditions are a function of solvent,
temperature, concentrations, residence time and liquid
depth and can be studied with the right physical description
- Confidence that the CFD will predict actual performance
- If our CFDs don't do what we say they will, there is
no charge. Our confidence is backed by this guarantee!
- Allow
Post Mixing to test or audit current conditions
of your existing SX-plant
- See if a CFD-model also predicts your actual flow
rate
- Solicit and test ideas on the computer without
plant shutdown and loss of production to see what is
wrong
- Design a new pumper impeller
- to provide the head and flow your site was originally
designed to operate at (if you are having troubles
achieving them)
- to provide the head and flow your site would like
to have (if you are planning plant production increases)
- Of course you know that the blade curvature makes
a difference!
- Did you know that blade height makes a difference?
- Did you know that the length of these blades make
a difference?
- Did you know that curved bladed pumpers still pump
and provide flow if you spin them backwards? Do you
know how it affects your plant performance?
- Did you know how sensitive the head and flow is to
the clearance between the bottom of the blades and
the false bottom?
- Did you know that what you do to a pumper
directly above the orifice makes a difference?
- Did you know that no pumper design is ideal under
every circumstance?
- Help with other design concepts, such as:
- Optimize baffles
- Optimize orifice size for the intended flow
(did you know it makes a difference?)
- Optimize the size of inlet and outlet pipes
- Optimize what's under the false bottom
- Optimize the overflow - underflow connections or
weirs
- Have
Post Mixing write the specs for the mechanical solution
and optimize your SX operation
- Often we can prescribe just replacing the
pumper impellers and leave the same or reduce the
speed and motor power. A production increase can't
get any cheaper: No change gears, no new motors,
no new gearboxes.
- We are aware of bad operational conditions
and we will steer you away from them.
- We are cognizant that over powering your pump
boxes will induce air from the head space, increase
crud formation, increase entrainment levels by
creating droplets that are too fine in size, increase
the level in the pump boxes, and reduce the efficiency
of your settlers.
- We are cognizant that under powering your pump
boxes will cause premature phase separation, can
cause water-lock, dramatically increase the levels
in your pump-boxes, unnecessarily increase the head
demand on your pumpers, reduce overall
hydraulic efficiency, and reduce mass transfer
efficiency.
- We are very aware that the effects of over powering
and under powering are dependent on the pumper design
and increasing power as a brut force method of achieving
a design condition is no substitute for a well
designed pumper and pump tank.
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