COOLING WATER SCALE AND CORROSION INHIBITION
First Claim
1. A method for controlling silica or silicate scale formation in an aqueous water system with silica contributed by source water, the methods of the present invention comprising the steps:
- a) removing hardness ions from said source water, b) controlling the conductivity of said aqueous system water such that said aqueous system water possesses a measurable conductivity of at least 1 μ
mhos; and
c) elevating and maintaining the pH of said aqueous system water such that said aqueous system water possesses a pH of approximately 9.0 or greater.
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Accused Products
Abstract
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.
14 Citations
32 Claims
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1. A method for controlling silica or silicate scale formation in an aqueous water system with silica contributed by source water, the methods of the present invention comprising the steps:
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a) removing hardness ions from said source water, b) controlling the conductivity of said aqueous system water such that said aqueous system water possesses a measurable conductivity of at least 1 μ
mhos; and
c) elevating and maintaining the pH of said aqueous system water such that said aqueous system water possesses a pH of approximately 9.0 or greater. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 27, 29, 31)
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14. A method for inhibiting corrosion of a metallic substance in an aqueous system containing soluble SiO1 of greater than 10 mg/L wherein said aqueous system derives water from make-up source water, comprising the steps:
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a) removing hardness ions from said source water;
b) controlling the ionic strength of the aqueous system water such that said aqueous system water possesses a measurable conductivity of at least 1 μ
mhos;
c) elevating and maintaining the pH of said aqueous system water such that said aqueous system water possesses a pH of approximately 9.0 or greater; and
d) cyclically contacting said aqueous system water with said metallic substance, wherein said pH and ionic strength increases the amount of soluble silica in the multimeric form present in said aqueous system water and inhibits corrosion of said metallic substance. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 28, 30, 32)
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Specification