Inventor(s)
Assignee
Application
No. 11018170 filed on 2004-12-21
Examiners
Attorney, Agent or Firm
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Abstract
A methods of the present invention for
inhibiting silica scale formation and corrosion
in aqueous systems where soluble silica
residuals (SiO2) are maintained in excess of 200
mg/L, and source water silica deposition is
inhibited with silica accumulations as high as
4000 mg/L (cycled accumulation) from evaporation
and concentration of source water. The methods
of the present invention also provides
inhibition of corrosion for carbon steel at
corrosion rates of less than 0.3 mpy (mils per
year), and less than 0.1 mpy for copper, copper
alloy, and stainless steel alloys in highly
concentrated (high dissolved solids) waters. 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.
Other References
- 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.
30-31.
- Rozenfeld, I.L.; Corrosion Inhibitors;
1981; McGraw Hill; 171-174.
- Strumm, et al.; Formation of
Polysilicates as Determined by Coagulation
Effects Environmental Science and
Technology; 1967; Vo. 1, 221-227.
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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 environment
US Patent References
5277823
Silica scale inhibition
Issued on: January 11, 1994
Inventor: Hann, et al.
5403521
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
Inventor: Takahashi
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