DOWEX Ion Exchange Resins WATER CONDITIONING MANUAL

The UPCORE Counter-Current Regeneration System
8 THE UPCORE COUNTER-CURRENT REGENERATION SYSTEM
The UPCORE system from Dow Liquid Separations is a modern downflow service, UPflow COuntercurrent
REgeneration packed bed technology for ion exchange demineralizers, water softeners, and other
applications. The technology is self-cleaning and can be applied to new plant designs and also to
rebuilding and upgrading existing installations. Dow has developed a range of uniform DOWEX UPCORE
Mono ion exchange resins for this system.
8.1 Process Description
The vessel is almost completely filled with ion exchange resin, and there is a small freeboard above the
resin bed to allow for resin movement and swelling. The top collector/distributor system in the vessel is
surrounded by a shallow layer of floating inert material that allows free passage of spent regenerants and
rinse water as well as resin fines and other suspended solids, while retaining the normal-size resin beads
in the vessel. Vessels designed for the UPCORE system are therefore straightforward and inexpensive. If
existing co-current resin beds are converted to this counter-current technology, system modifications are
minimal and plant capacity can be nearly doubled.
With the UPCORE system, the service (loading) cycle operates downflow, so the settled resin bed is
insensitive to fluctuations in feed flow because the bed stays fixed against the bottom distribution system.
If feed flow is interrupted, there is no danger that ionic stratification will be disturbed. The highly
regenerated polishing zone at the bottom of the bed remains intact and uncontaminated by exhausted
beads higher up in the bed.
During upflow regeneration, the resin bed is first lifted as a fixed bed and compacted against the floating
inert resin layer with dilution water. Once compacted, the regenerant then passes upflow at a rate
sufficient to maintain the resin in the packed state. So the upflow compaction and regeneration steps
serve two purposes: cleaning the vessel of resin fines and other particulates and reactivating the ion
exchange sites on the resin. No separate backwash step is needed. Suspended solids and resin fines are
automatically removed during the compaction step of each regeneration cycle. Figure 18 illustrates
service and regeneration cycles with the UPCORE system.
Figure 18. Service and regeneration cycles with UPCORE system.
PRODUCTION CYCLE REGENERATION CYCLE
Feed water Effluent waste
Floating inert
Freeboard
DOWEX UPCORE
Resin
Freeboard
Product water Regenerant
DOWEX Ion Exchange Resins 41 Water Conditioning Manual