2. What is After Cation
Conductivity(ACC)
• Cation Conductivity also known as
Acid Conductivity and Conductivity
After Cation Exchange (CACE) is
the measure of electrolytic
conductivity of a liquid sample after
that liquid sample has passed
through an ion exchange
resin column containing cation resin
in the hydrogen form.
3. WHY ACC IS MEASURED
The measurement was adopted for
monitoring the power plant steam / water
cycle as it can detect low levels of anion
contaminants such as chlorides, sulphates,
and organic acids (parts per billion) on a
continuous basis, while at the same time the
measurement is very simple and easy to
maintain.
4. Where ACC Measured?
Typically measured on Main Steam or Reheat Steam samples,
Condensate samples, Feed-water samples, and Boiler or Heat
Recovery Steam Generator evaporator drum samples
TYPICAL DIAGRAM OF A POWER PLANT
5. SIGNIFICANCE OF ACC
• In the power plant Steam-water cycle is maintained at a
high purity level to minimize the potential for corrosion
and deposition. This steam and water will typically be
conditioned with an alkaline chemical such as ammonia
to further reduce the potential for corrosion.
6. • In practice, a cooled sample of condensate or high purity water flows
through a cation exchanger in the hydrogen form. The cation resin
replaces contaminating cations such as Ca++, Mg++, Na+, NH4+,
and amines in the sample with hydrogen ions.
HOW ACC MEASURED
NaCl, KCl , CaSO4,MgCl , NH4OH etc
Contaminated Sample with minerals
HCl, H2SO4, H2O etc
+ Na+Cl-
Na+ + HCl
ION-EXCHANGE REACTIONS
(CATION EXCHANGE RESIN)
(MINERAL)
(ACID)
CATION COLUMN
7. HOW ACC MEASURED…
• The hydrogen ions exchanged for the other cations in the
sample increase the conductivity contributed by the
contaminant salts of mineral acid anions listed above by 3
or 4 times. Thus the cation exchange column can be
thought of as a "conductivity amplifier" for mineral and
organic acid contaminants; increasing the sensitivity of
the conductivity analyzer to low levels of contamination. "
IN CASE OF CONTAMINATION
IN CASE OF NORNAL SAMPLE CONDITIONING
