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.
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.
Type:
Grant
Filed:
January 9, 2004
Date of Patent:
August 16, 2005
Assignee:
Water & Enviro Tech Company, Inc.
Inventors:
Dan A. Duke, John L. Kubis, John P. Wetherell