Trane Cold Generator CG-SVX044F-EN Installation, Operation And Maintenance Manual page 41

Cleaning in Place (CIP) Procedure
Start
1. Shut off relevant pumps
2. Shut off the primary side's valves
3. Shut off the secondary side's valves
4. Empty the BPHE
5. Wash it with water to remove loose contamination
6. Connect the machine via inlet/outlet at front or backside
7. Mix chemical and water according to instructions such as
for Scale 132 Copper
8. Heat the solution to 120-140?F, make use of primary side
heat if possible
9. Pump the solution in the BPHE using the lower opening to
ventilate air. A flow rate corresponding to 1.5 times the
normal flow rate is suitable. Reverse the flow direction
every 30 min if possible. Monitor the pressure differential.
A pressure differential equal to design criteria indicates a
clean BPHE. Alternatively, monitor pH. Constant pH value
for 30 minutes indicates a clean BPHE. For Scale 132
Copper pH of 3 indicates the need to renew the cleaning
solution, then empty the BPHE and restart at point 5. The
cleaning time varies, but is estimated to 4-8 hours.
Stop
10. Flush from the lower opening for 5 minutes before
changing direction. Repeat this operation until no more dirt
is flushed out
11. Empty the BPHE and the machine, handle the used
solution properly
12. Flush the BPHE with water starting from the lower opening
until pH 7
13. To pickle and passivate steel use 2% phosphoric acid at
50°C (120°F) for 4-6 h.
14. Flush the BPHE with water starting from the lower opening
until pH 7
CIP Fluids
Bio Gen Active – Scale 132 Copper
Commercially available Scale 132 Copper removes lime scale
and other carbonates as well as rust and other metal oxides
without the risk of corrosion.
Organic Acids
Organic acids are less hazardous than mineral acids, which
makes them a good choice for BPHE cleaning. Organic acids
include formic, acetic, and citric acids, among others, and are
commonly applied at concentrations between 1 and 5 volume
percent.
Formic Acid
Formic acid alone is unable to remove iron oxide why it's used
as a mixture with citric acid or HCl. Formic acid can be used on
CG-SVX044F-EN
stainless steels, it's relatively inexpensive and can be disposed
by incineration.
Acetic Acid
Dissolves lime scale, but doesn't remove iron oxide deposits.
Since it's weaker than formic acid, it is preferred where long
contact times are necessary.
Citric Acid
Mild iron contamination can be removed by using a mixture of
1% each of citric acid and HNO3. For more persistent
contaminations, stronger solutions must be used.
Bases
Bases have the ability of removing oil, grease and biological
deposits from the heat exchanger surface and may be applied
as a complement during cleaning. They may also be added at
the end of the cleaning procedure, before the last rinse with
water, to neutralize any acid content left in the system. A
solution of 1-2% sodium hydroxide (NaOH) or sodium
bicarbonate (NaHCO3) before the last rinse ensures that all
acid is neutralized.
CIP Pumps
Important features:
• The reservoir should be made in acid- and alkali-resistant
material.
• The hoses should be made in PVC.
• A reverse flow device enables attack of lime scale from
both directions.
• A heating device enables the CIP solution to reach much
better effect.
• The flow rate capacity depends on the size of the BPHE.
COMMERCIALLY AVAILABLE CIP FLUIDS
Bio Gen Active – Scale 132 Copper
Description: Scale 132 effectively removes lime scale and
metal oxides (e.g. rust) without etching the material. It's used
for reconditioning of waterborne systems. The product is mild
to user, material and the environment.
Maintenance
41