A methods for inhibiting silica scale formation
and corrosion in aqueous systems where soluble
silica (SiO2) can be maintained at residuals
below 200 mg/L, but more preferably maintained
at greater than 200 mg/L as SiO2, without silica
scale and with control of deposition of source
water silica accumulations as high as 4000 mg/L
(cycled accumulation) from evaporation and
concentration of source water. The methods of
the present invention also provide highly
effective inhibition of corrosion for carbon
steel, copper, copper alloy, and stainless steel
alloys. The methods of the present invention
comprise pretreatment removal of hardness ions
from the makeup source water, maintenance of
electrical conductivity, and elevating the pH
level of the aqueous environment. Thereafter,
specified water chemistry residual ranges are
maintained in the aqueous system to achieve
inhibition of scale and corrosion.
- The NALCO Water Handbook; 1979; Chapter
3, p. 14 and 16.
- Drew; Principles of Industrial Water
Treatment; Sixth Edition; 1983; Chapter 3,
pp. 43 and 64.
- Boffardi, Bennett P., PhD; Calgon
Internal Publication; 1988; Chapter 4; pp.
- Strumm, et al.; ‚??Formation of
Polysilicates as Determined by Coagulation
Effects‚?Ě; Environmental Science and
Technology; 1967; vol. 1, 221-227.
- Rozenfeld, I.L.; ‚??Corrosion
Inhibitors‚?Ě; 1981; McGraw Hill; 171-174.
Current US Class
422/3 , Process control in
response to analysis
159/47.1 , PROCESSES
203/10 , WATER PURIFICATION ONLY
210/652 , Hyperfiltration (e.g.,
reverse osmosis, etc.)
210/687 , Calcium or magnesium
(e.g., hardness, water softening, etc.)
210/696 , Preventing, decreasing,
or delaying precipitation, coagulation or flocculation
422/13 , Aqueous alkali
environment (i.e., pH £ 4.1)
422/14 Essentially pure water
US Patent References
Silica scale inhibition
Issued on: January 11, 1994
Inventor: Hann, et al.
Blow system and a method of use
therefor in controlling the quality of recycle cooling water in
a cooling tower
Issued on: April 4, 1995