Atlas Copco ZR 200, Инструкция

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Ryznar Stability Index (RSI)
The Ryznar Stability Index (RSI) is a parameter for predicting whether water will tend to dissolve
or precipitate calcium carbonate. The adhesion of scaling deposits and their effect are different
on different materials, but the equilibrium of the water (scaling or corrosive) is only determined by
its actual pH value and by the saturation pH value (pH
s
).
The saturation pH value is determined by the relationship between the calcium hardness, the
total alkalinity, the total solids concentration and the temperature.
The Ryznar Stability Index is calculated as follows :
RSI = 2*pH
s
- pH
Symbol Explanation
pH Measured pH (at room temperature) of water sample
pH
s
pH at saturation
The pH
s
is calculated by using :
pH
s
= (9.3 + A + B) - (C + D)
Symbol Calculation
A
(
10
log(TDS) - 1) / 10
B
13.12 x
10
log(°C+273) + 34.55
C 10
log(Ca
2+
) - 0.4 (Ca
2+
expressed as ppm CaCO
3
)
D
10
log(M-Alkalinity) (M-Alkalinity expressed as ppm CaCO
3
)
RSI and chloride limitation
Single Pass system
RSI Chloride
limit Water condition Maximum 65°C /
149°F Maximum 95°C / 203
°F
RSI<3.9 200 ppm Very high scale formation Water cannot be used. Not applicable.
4.0<RSI<5.5 200 ppm High scale formation Regular control and
descaling operation
necessary.
Not recommended for
plate heat exchangers Not applicable.
5.6<RSI<6.2 350 ppm Slight scale formation Water treatment not
necessary.
Occasional inspection
recommended. Not applicable.
6.3<RSI<6.8 500 ppm Neutral water Water treatment not
necessary.
Occasional inspection
recommended. Water treatment not
necessary.
Occasional inspection
recommended.
Instruction book
68 AIF999999