a) Flushing: Operate the chemical circulation pump to flush the system with demin water until the effluent is clear and then drained completely. During flushing, all vents and drains must be opened to remove the roots particles, dirt and deposit.
b) Leak-test: Use chemical circulation pump to leak test the system at the maximum discharge pressure.
c) Heating-up: Fill the system with demin water and continue circulate the system with chemical circulation pump and heating up the water to 60 – 80 Maintain the temperature by temporary heat exchanger.
d) Degreasing: Add Surfactant in the continuously circulate system. While circulation, maintain the temperature for approx. 4 hours. (For remove of oil and grease for prepare the surface before acid cleaning)
e) Acid cleaning: Continue circulate. Add Corrosion inhibitor + Citric acid + Ammonium Bi-fluoride and temperature for adjust the pH with Ammonia water to approx. 3-4. Main the temperature at 60 -80 and monitor the cleaning by analyzing the concentration of acid and total iron every half an hour. When the analysis shows equilibrium result then stop heating for cool down.
f) Neutralization: Adjust pH of the solution with Ammonia water for neutralized.
g) Passivation: Slowly add sodium nitrite and continue circulation to complete the passivation step.
h) Draining & Rinsing: Drain the solution to waste storage and rinse the system with demin water. Circulate and grain the rinsing water until the system is empty.
Note: All waste solution from chemical cleaning shall be carried to outside for dispose