Cleaning of Cooling Water System

STANDARD PROCEDURE

FOR FLUSHING, CHEMICAL CLEANING & PASSIVATION

OF COOLING WATER CIRCUIT

PURPOSE:

This document describes the complete procedure of the flushing, chemical cleaning and passivation of cooling water circuit

CHEMICALS REQUIRED:

1) Sulfuric Acid required = Kg

2) Rodin required = liter

3) Aquatreat 102 = Kg

4) NaOH = Liter

5) Aquatreat-401 biocide = Liter

Safety Precautions:

1) Wear Chemical suit during chemical handling

2) Use required PPE (safety shoes, goggles, chemical mask, face shield etc)

3) Unauthorized entry is not allowed.

4) During sampling safety gadgets must be used.

5) No work should be allowed with out work permit.

1.0 INITIAL PREPARATION

1. Steam header pressurization as per SOP.

2. All the maintenance jobs are completed at cooling tower.

3. Ensure Cooling water circulation pumps are ready for operation.

4. Ensure all the cooling water exchangers of Ammonia and urea plant must be boxed up properly.

5. Ensure the availability of required chemicals mentioned above.

2.0 CHEMICAL CLEANING PROCEDURE

0. Flushing

2.1.1 Ensure that the water circulation should be through the whole cooling water circuit.

2.1.2 It is necessary that the water velocity is as high as possible. Minimum and positively 6,500 to 7,000 M3/hr. flow is required till the completion of flushing and cleaning job.

pH for this stage:    7.5 to 8.0

Duration:                4 to 6 hours.

1. Surfactant Cleaning.

1. Start adding caustic, NaOH (as surfactant) to the basin of cooling tower until achieve the pH of the circulated water about 12.0.

2. Continue circulation for 2 to 3 hrs without blow down.

3. pH value should be observed and retained the pH by adding caustic, if required.

4. During this activity log the Ca+ and turbidity.

5. After 2 or 3 hrs Start the heavy blow down till the circulation water...