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How to Clean Heat Exchanger Plates

5 Most Common Plate Heat Exchanger Cleaning Methods

  1. Mechanical Cleaning
  2. Chemical Cleaning
  3. Clean-in-Place (CIP)
  4. Back Flushing
  5. Disassembled Cleaning

1. Mechanical Cleaning Process for Plate Heat Exchangers

Mechanical cleaning involves opening up the heat exchanger unit and using synthetic bristle brushes, high-pressure water spray, and other specialized tools to mechanically wash the plates.

The following steps outline a typical procedure for mechanical cleaning of plate heat exchanger units:

    1. Loosen the plate pack and remove the tie rods to open the heat exchanger unit. Slide the plates and space them apart to allow enough room for cleaning by brush or pressurized spray water.
    2. Mechanical cleaning can be done with a soft brush with synthetic bristles, not steel bristles, and running water, with care to not damage the gaskets.
    3. High-pressure water is used to clean each plate individually, while hanging in the unit or removed.
    4. The gaskets must be wiped with a dry cloth to remove any solid particles which might be adhering to gasket surfaces that can cause leakage when the unit is re-assembled.
    5. After inspection of each plate, the unit is closed and tightened to specifications from the assembly drawings and tightening instructions.

2. Chemical Cleaning Process for Plate Heat Exchangers

Chemical Cleaning solution concentrations should be limited to 4% in strength, with temperatures not exceeding 140°F unless otherwise specified.

Common Plate Heat Exchanger cleaning chemicals include:

    1. Nitric acid
    2. Sulfamic acid
    3. Citric acid
    4. Phosphoric acid
    5. Complexing agents (EDTA, NTA)
    6. Sodium Polyphosphates

3. Clean-in-Place (CIP) Process for Plate Heat Exchangers

CIP is recommended for high fouling applications where frequent cleaning is required. It is especially beneficial for prolonging plate life in highly corrosive applications.

The following steps outline a typical procedure for clean-in-place of plate heat exchanger units:

    1. Close all of the isolating valves and drain the heat exchanger through the CIP system or force liquids out of the unit with flush water.
    2. Flush both sides of the unit with warm water ( 100-120 Deg F ) until the effluent water is clear and free of process fluids.
    3. Completely drain the rinse/flush water from the CIP system.
    4. Refill the CIP system with water and add the appropriate cleaning solution.
    5. Circulate the cleaning solution at 140-180 Deg F for 3-6 hours.
    6. When cleaning multiple pass units, reverse the flow for ½ of the cleaning time to ensure that cleaning solution contacts all internal surfaces.
    7. For optimum cleaning, use the maximum flow rate of water, rinse, or CIP solution that the CIP nozzle size will allow (2 in. @ 260 gpm, 1 in. @ 67 gpm.)
    8. and before the unit is completely fouled.
    9. Drain the cleaning solution from the CIP system and flush the unit again with warm water following steps two and three.
    10. Close the valves to the CIP system and reopen the main isolating valves to the heat exchanger.
    11. Start-up the heat exchanger.

A CIP operation will be most effective if performed on a regularly scheduled basis before the unit is completely fouled.

4. Backflushing Process for Plate Heat Exchangers

Backflushing is recommended method for keeping a heat exchanger in service that is prone to clogging from solids, fibers, and/or sediment.

The following steps outline a typical procedure for backflushing plate heat exchanger units:

    1. Make provisions in the piping to allow for the reverse flow of the problem fluid. This is backflushing.
    2. The backflushing should be done with water at 1.5 times the normal flow.
    3. Problem fluids should normally enter at the bottom of the exchanger and exit at the top so particulate is trapped at the lower portion of the unit and does not make its way in between the heat transfer plates.
    4. An alternative backflushing method is to have the ability to reverse both fluid’s flow direction and to do this periodically.
    5. The use of strainers is recommended in supply lines ahead of the exchanger when the streams contain significant solids or fibers. This will reduce the requirements for backflushing.

5. Disassembled Cleaning Process for Plate Heat Exchangers

In some situations, CIP will not be effective and the plate heat exchanger must be dismantled to be cleaned.

The following steps outline a typical cleaning procedure for disassembled plate heat exchanger units:

    1. Open the heat exchanger.
    2. Slide the plates apart to allow for cleaning by a soft brush or water rinsing while the plates remain in the frame.
    3. When using a water jet to clean the plates they must be placed on a flat surface and the jet spray directed away from the gaskets to avoid damaging them.
    4. Do not use a steel brush or steel wool for cleaning the plates as damage to them can occur.
    5. Be careful not to scratch the gasket surfaces.
    6. Use the appropriate cleaning solution for the type of fouling.
    7. Apply the cleaning solution to the plates and let stand as necessary. Brush and rinse. If necessary, repeat the process.
    8. After final brushing, rinse well with water and then wipe dry.
    9. Inspect all parts before reassembly.

5 Common Reasons Plate Heat Exchangers Need Regular Cleaning

Note: Fouling can be minimized by increasing the velocity of fluids through the heat exchanger to increase turbulence which removes deposits from heat transfer surfaces.

  1. Scaling
  2. Sediment Fouling
  3. Gross Fouling
  4. Biological Fouling
  5. Residual Fouling

1. Scaling

Scaling is a common type of fouling that is caused by high concentrations of carbonates in the heat exchanger’s cooling water and is removed either by manual or chemical cleaning is usually comprised of:

    1. Calcium Carbonate
    2. Calcium Sulphate
    3. Silicates

2. Sediment Fouling

Sediments that collect within heat exchangers are usually comprised of:

    1. Products of Corrosion
    2. Metal Oxides
    3. Silt
    4. Alumina
    5. Diatomic organisms and their excrement

3. Gross Fouling

Gross fouling is typically caused by:

    1. Seaweed
    2. Wood chips and wood fibers
    3. Mussels
    4. Barnacles

4. Biological Fouling

Biological fouling describes the growth of slime and organic matter that results from:

    1. Bacteria
    2. Nematodes
    3. Protozoa

5. Residual Fouling

Residual fouling is caused by is hydrocarbon-based deposits from:

    1. Oils
    2. Asphalt
    3. Fats

Important Heat Exchanger Cleaning Guidelines & Notes

  • Never use Hydrochloric Acid (Muriatic acid) with Stainless Steel Heat Exchanger Plates.
  • Never use Hydrofluoric Acid with Titanium Heat Exchanger Plates.
  • Never use water with chloride concentrations greater than 300 ppm to clean Stainless Steel, Hastelloy, 254SMO plates. Chlorine is commonly used to inhibit bacteria growth in cooling water systems. However, chlorine reduces the corrosion resistance of stainless steel, Hastelloy, Incoloy, Inconel, and 254SMO. Chlorine does not present the same corrosion risk for Titanium heat exchanger plates.
  • Never open the unit when it is hot, under pressure, holding a liquid, or while it is operating.
  • Always use clean water (free from salt, sulfur, chlorine, or high iron concentrations) for flushing and rinsing operations.
  • If steam is used as a sterilizing medium, do not exceed 270°F steam temperature with nitrile gaskets and 350°F with EPDM gaskets.
  • Always add concentrated cleaning solutions to water before circulating through the unit. Never inject these solutions while the water is circulating.
  • Cleaning solutions should always be circulated with a centrifugal pump.
  • Thoroughly rinse the plates with clean water following any type of chemical cleaning.
  • When using high-pressure water, the heat exchanger plates must be laid flat to avoid damage.

Heat Exchanger Cleaning Tools

  • Mobile CIP (Clean-in-Place Unit)
  • High-Pressure Water Spraying Wand
  • Synthetic Fiber Brushes

Frequently Asked Questions include:

Q: How often does a heat exchanger need to be cleaned?
Q: What is the best heat exchanger preventive maintenance procedure?
Q: Where can I find a professional heat exchanger cleaning service near me?
Q: How do you clean a clogged heat exchanger?
Q: How do I know if my heat exchanger is blocked?