25 May 2005
d) Fill the system with makeup water and circulate for 30 minutes.
e) Take a sample of system water while it is circulating. The sample should
match the makeup water supply for clarity and SS; conductivity 10%; and
pH 0.3 pH units from 7.5 to 8.5.
If necessary, repeat steps a) through e) until the system water matches this
description. The system should now be clean and passivated.
Chemical Cleaning and Passivation Formulation. Apply this chemical
cleaning and passivation formulation when the water system pH is 7.5 to 8.5; adjust pH
as required. Formulation limitations may require adding separate components to keep
things in solution. Other formulations may be used.
Orthophosphate (or) hexametaphosphate (as PO4): 60 ppm
Polyacrylate (active): 20 ppm
Tolyltriazole (active): 10 ppm
Sodium gluconate: 50 ppm
Pluronic L-61 (active) (non-ionic surfactant with antifoam): 400 ppm
Phosphate scale inhibitor: 50 ppm
Passivation of the System. Supplemental corrosion inhibitors may be
used in conjunction with the phosphate but are not required. Maintain and circulate the
levels for the time required. After passivation, proceed to operational readiness or layup
as required. Tables 4-14 and 4-15 show chemical technology used for passivation.
Operational Readiness. If system operation is not required for a period of
a week or more, proceed to layup. For normal operation, allow corrosion inhibitor levels
to subside to maintenance levels through normal blowdown. Proceed to maintenance
water treatment program.
Table 4-14. Required Chemical Technology
40-60 ppm as PO4
20-30 days as PO4
10-20 days as TTA