Cooling tower Pretreatment Chemical

Cooling tower Pretreatment Chemical

Cooling towers Chemical Pretreatment necessary considering the construction of a building, take a long time, from the start of civil works, construction, electrical, cooling system and work other jobs, up to the stage of finishing work.

During the construction process takes a long time, cooling tower water systems already installed will be contaminated by mud, dust, garbage construction work, the rest of the welding, cement, the growth of algae, slime, bacteria, fungi, the process of the formation of rust / corrosion, which if not pre-treatment process is carried out will greatly disrupt the performance of the system.

Another Kontaminant is oil, grease, oil, which is used by the manufacturer / supplier of metal to prevent rust during the process of production and storage in the warehouse. If oil, oil, grease, not cleaned, it will hinder the process of passivation / protective coating films (corrosion inhibitor).

Before the handover from the contractor to the owner of the building, Cooling Tower Water System already installed should do the Pre-Treatment beforehand, so that at the time of start-up and commissioning of the cooling tower is already ready to use, clean and coated with a layer of corrosion inhibitor or protective films.

Equipment life and performance Cooling Tower Water System will be largely determined by the pre-treatment applied prior to Start-Up. The coating process protective film on the entire surface of the metal will protect Cooling Tower Water system from the onset of rust, so that the life of the equipment can be longer.

System performance will be optimized, the process of heat exchange in the heat changer as condensor will be maximized because the surface clean of scale, rust, slime, mud, dirt, garbage and others.

Pre-Treatment is a technical effort that must be done prior to cooling tower water system is operated by means of cleaning and passivation of the surface of the metal in the cooling tower water system.

There are two pre-treatment stages, namely:

  1. Cleaning the entire surface of the metal in the cooling tower water system.
  2. The process of passivation or coating of protective film on the metal surface.


In working on projects in the Pre-Cooling Tower Water Treatment System there are steps that must be done in order to get good results and maximum. The steps outlined in the Standard Operation Procedure Pretreatment.

The SOP we recommend is as follows:

  1. Pre-Treatment Inspection

Before the pre-treatment carried out must first be inspected all equipment is in the cooling system. If it is found that excessive corrosion products, deposits or foulant, then it must be cleaned with appropriate cleaning procedures.

  1. Flushing
    Basin and sump cooling tower must be drained and cleaned of dirt, mud, corrosion products, scale, microbiological debris, algae, slime, scum, and other kontaminant. Cooling tower systems must diflushing thoroughly, including playing horizontal headers.
    After that then close Valve blow down, fill the system with clean water sources, and circulate.
    Then open the valve blow down, do flushing using water source for 24 hours or until the system really clean.
    Stop blow down, adjust the pH of the water circulating in figures 6 to 6.2 by the addition of acid pH adjuster, keep the pH range for 3 days without blow down.
    After the circulation for three days, did blow down and continue until the Total Suspended Solids (TSS) below 30 ppm.
    Stop blow down, reduce the addition of acid pH adjuster, increase the pH of the water circulating in the numbers from 7.5 to 8.0, keep the pH ranges in these figures during the passivation process.

    1. Add Formax 200 slowly with the help of gravity to achieve the level of 80-100 mg / liter as PO4. If necessary add Alkaline pH adjuster into the cooling tower water system to maintain the pH in number from 7.5 to 8.0.
    2. Add Formax 201 to reach the level of 40-50 mg / liter as PO4. Stop adding Formax Formax 201 after the addition of 200 was perfect and the pH has stabilized.
    3. Add Formax 20-30 mg / liter and add it again with the same dose after 24 hours. Do this slowly because it will produce foam.
    1. Do a shock chlorination every day to achieve the free residual chlorine at the level of 68.05 mg / liter in the cooling water return line for 30 minutes. Stop adding acid pH adjuster temporarily, during the chlorination process.
    2. Continue circulation under these conditions for 7 days.
    3. Keep the chemical concentration at the level as follows:
      1. Formax 201 sebagai PO4 40 – 50 mg/ liter
      2. Formax 200 sebagai PO4 80 – 100 mg/ liter
      3. pH 7,5 – 8,0
  • After the circulation for 7 days, the total system must curl down. Measure the content of TSS to levels below 30 mg / liter.
  • pH, Formax 200, 201 Formax levels should be monitored regularly during operation and maintained in order to be at the recommended level. The frequency analysis is as follows
    • During the process Cleaning with low pH water
      • pH per 2 Hours
      • TSS/ Turbidity per 4 Hours
    • During the passivation process
      • pH per 2 Hours
      • In organic phosphate per 2 Hours
      • Organic phosphate per 4 Hours
  • To ensure that the process of Pre-cleaning and Pre-movie work, do a test with testing standard coupon.
    1. Alat
      1. TSS/ Turbidity tester
      2. pH tester
      3. Inorganic phosphate tester
      4. Organic phosphate tester
      5. Chlorine tester
      6. Coupon tester
      7. Termometer
    2. Materials
      1. Formax 200
      2. Formax 201
      3. Formax 203
      4. Formax 051 B
      5. Alkaline pH adjuster
      6. Acid pH adjuster

Factor of safety, occupational safety and accident prevention must be observed when handling the chemicals used. Protective clothing and safety items should be worn to prevent injury during pre-treatment process.

  1. NOTE
    1. Pretreatment program must be done first before the regular treatment.
    2. Doses are calculated based on the volume of chemical systems and the addition of chemical dose is calculated based on lab test results.
    3. If the water temperature over 40 C system, the dosage Formax 201 on passivation step should be reduced. Attain PO4 content at 20 -25 mg / liter



For New Cooling Tower

Before Start-Up or Commissioning

Arranged by

Ece Suratma


Office : Ruko Griya Suradita Indah Blok A3 No. 6

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