¤ The Driplex system
The essential feature of this system is the design and operation
of the external regeneration vessels. The use of conical type
units achieves a minimisation of the surface area of the
separation zone - on a typical design for a 500 MW set, this can
be of the order of a factor of 10x, when combined with a
carefully designed flow system (when compared with
conventional sluicing systems which are inherently turbulent) it
can be readily seen that the efficiency of the resin separation is
much higher.
This improvement in the Driplex system has two
major benefits:
1. Very little cation resin is subjected to the very
high sodium levels in the regeneration and similarly, the anion
resin doesn't see the acidic radicals. Consequently, the
leakage of salts during service operation due to inefficient
regeneration is minimised.
2. Minimised / elimination of loss of
the resin capacity, which occurs with conventional systems due
to contamination loss.
For long term boiler system integrity and polishing plant
availability, together with regenerant costs, the Driplex Separation System clearly has major advantages.
¤ Partial Condensate Polishing
In many plants, designed for make up water production,
facilities are provided for condensate polishing as the final
stage of the plant. These plants allow for polishing of the total
feed for the periods, particular coincident with the generating sets.
This facility is becoming a standard inclusion in many deionisation plants provided to produce ultra pure make up water for boiler units operating at high pressures.
Condensate treatment is widely used in coal-fired thermal
power plants with super-critical boilers, where high purity
must be strictly maintained.
¤ Deep-bed Condensate Polishing
Deep-bed externally regenerated condensate polishing
systems use mixed-bed resin to filter out corrosion products
and remove trace dissolved minerals. Driplex offers deep-bed
condensate polishing design to control resin cross
contamination to less than 0.1 percent cation/anion and
anion/cation without chemical treatment.
¤ Powdered Resin Condensate System
Powdered resin condensate treatment is used in a thermal
cycle when the presence of dissolved solids is anticipated to be
moderately low. Powdered resin polishing is a much more
effective and stable means of filtering suspended matter from
the condensate. Although ion exchange performance is
good, powdered resin condensate treatment is not
recommended in cycles where there is a consistently high level
of dissolved solids. Driplex provides state-of-the-art powdered
resin filter elements for use in condensate polishing systems.
¤ Regenerating The Condensate Polishing Resin
When the resin in the condensate polisher is exhausted, it
needs to be regenerated - frequently on site, although off-site
regeneration is sometimes considered for eliminating on-site
waste handling and reducing site personnel requirements.
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