1. Acid problems in Ammonia Refrigeration Systems
Presented at:
IIAR 2003 Ammonia Refrigeration Conference & Exhibition, Albuquerque, New Mexico
Copyright WMI/L. F. 'TEX' Hildebrand 02/2003

2. Acid problems in Ammonia Refrigeration Systems
Presented by:
L. F. “Tex” Hildebrand
Copyright WMI/L. F. 'TEX' Hildebrand 02/2003

3. Acid problems in Ammonia Refrigeration Systems
IIAR Bulletin 108
Water in Ammonia causes
loss of capacity
Increase of horsepower
“Chemical changes to compressor oil. . .’
Organic acids
Sludges
etc.
Copyright WMI/L. F. 'TEX' Hildebrand 02/2003

4. Acid problems in Ammonia Refrigeration Systems
Water, if left unchecked, in an ammonia refrigeration plant will result in:
Contamination,
Sludge, and
Corrosion damage to components
Copyright WMI/L. F. 'TEX' Hildebrand 02/2003

5. Acid problems in Ammonia Refrigeration Systems
Symptoms of contamination
Strainers clogging.
Corrosion failure to float valve cartridges, solenoid valves, thermal expansion valves, check valves, etc. (wherever liquid is throttled).
Sight glasses coated from inside with a brown emulsion (gooey stuff!).
Problems maintaining evaporating temperatures.
Copyright WMI/L. F. 'TEX' Hildebrand 02/2003

6. Acid problems in Ammonia Refrigeration Systems
Causes of contamination - Let us look at The Players and their roles:
AMMONIA
COMPRESSOR
OIL
AIR
WATER
CO2
DISSOCIATION BY-PRODUCTS
SLUDGE (BECOMES THE “MAALOX”)
ANAEROBIC BACTERIA
ORGANIC ACID(S)
Copyright WMI/L. F. 'TEX' Hildebrand 02/2003

7. Acid problems in Ammonia Refrigeration Systems
Remedies
The actual remedy applied will vary with the extent of contamination found in the system. Generally the following class conditions will apply:
1. When contamination is discovered at an early stage
2. When contamination has progressed to a more serious state
3. A very seriously contaminated system
Copyright WMI/L. F. 'TEX' Hildebrand 02/2003

8. Acid problems in Ammonia Refrigeration Systems
Remedies (Class Condition-1). NOTE: This remedy should be used in conjunction to all others.
Install an ammonia still to remove the water and stop the contamination from progressing.
Liquid filters in pumped liquid lines will help clean up the contamination. (However, if water is not removed, contamination will continue to grow).
Copyright WMI/L. F. 'TEX' Hildebrand 02/2003

9. Acid problems in Ammonia Refrigeration Systems
Remedies (Class Condition-2).
Shut down system and remove all ammonia charge.
De-hydrate entire system with appropriate evacuation
Re-charge system with refrigeration grade ammonia.
Insure proper ventilation if CO2 is in use in plant processes.
Copyright WMI/L. F. 'TEX' Hildebrand 02/2003

10. Acid problems in Ammonia Refrigeration Systems
Remedies (Class Condition-3).
Shut down system and remove all ammonia charge.
Using an appropriate mixture of solvents, clean all vessels, and piping, if possible.
Clean or replace all sight glasses, strainers, throttling device kits.
Repair or replace all check valves.
Copyright WMI/L. F. 'TEX' Hildebrand 02/2003

11. Acid problems in Ammonia Refrigeration Systems
Remedies (Class Condition-3 Cont’d).
Change oil and filters on all compressors.
Dehydrate entire system with appropriate evacuation.
Re-charge system with REFRIGERATION GRADE AMMONIA.
Copyright WMI/L. F. 'TEX' Hildebrand 02/2003

12. Copyright WMI/L. F. 'TEX' Hildebrand 02/2003
PHILLIPS 701 Pilot Valve Parts (1)
New Parts
Damaged Parts       
Copyright WMI/L. F. 'TEX' Hildebrand 02/2003

13. Copyright WMI/L. F. 'TEX' Hildebrand 02/2003
PHILLIPS 701 Pilot Valve Parts (1)
Copyright WMI/L. F. 'TEX' Hildebrand 02/2003

14. Copyright WMI/L. F. 'TEX' Hildebrand 02/2003
PHILLIPS 701 Pilot Valve Parts (2)
Copyright WMI/L. F. 'TEX' Hildebrand 02/2003

15. Copyright WMI/L. F. 'TEX' Hildebrand 02/2003
Strainer basket
New
for comparison
Old
From -40 Deg. F. Liquid Makeup from Controlled Pressure Receiver 
Copyright WMI/L. F. 'TEX' Hildebrand 02/2003

16. Copyright WMI/L. F. 'TEX' Hildebrand 02/2003
TXV Cage Assembly 
New 
Used (1)
Copyright WMI/L. F. 'TEX' Hildebrand 02/2003

17. Copyright WMI/L. F. 'TEX' Hildebrand 02/2003
Damaged TXV Cage Assembly   
Used (1) Example of brown emulsion (gooey stuff!)  
Used (2)
Copyright WMI/L. F. 'TEX' Hildebrand 02/2003

18.   Damaged TXV Cage Assembly Used (1) Used (1)
Copyright WMI/L. F. 'TEX' Hildebrand 02/2003

19. Damaged TXV Cage Assembly
Used (2)
Used (2)
Copyright WMI/L. F. 'TEX' Hildebrand 02/2003

20.   Damaged Phillips Pilot Float Valve Cartridge Used
Copyright WMI/L. F. 'TEX' Hildebrand 02/2003

21.      Damage on In-Line Check Valve Parts
Copyright WMI/L. F. 'TEX' Hildebrand 02/2003

22. Acid problems in Ammonia Refrigeration Systems
Preventative Maintenance
Insure that ammonia still is installed and is functioning properly.
System Opening Policy (Line Breaking Permit Procedure).
Periodic inspections for negative pressure leaks (shaft seals, valve stems, etc.)
Copyright WMI/L. F. 'TEX' Hildebrand 02/2003

23. Acid problems in Ammonia Refrigeration Systems
Preventative Maintenance (Cont’d).
In plants where CO2 is used in the process, special care should be placed on proper ventilation systems to preclude the CO2 concentration from entering the Refrigeration System, through possible vacuum leaks or during service/maintenance operations.
Copyright WMI/L. F. 'TEX' Hildebrand 02/2003

24. Acid problems in Ammonia Refrigeration Systems
Preventative Maintenance (Cont’d).
Regular oil samples from all compressors should be analyzed for water, particle count, wear debris, Total Acid Number (TAN), and properties of the lubricant, i.e. viscosity, additive depletion, etc. Trend charts for monitoring change are useful.
Copyright WMI/L. F. 'TEX' Hildebrand 02/2003

25. Acid problems in Ammonia Refrigeration Systems
Preventative Maintenance (Cont’d).
Oil sample from new oil (to establish baseline) should be included with compressor oil samples.
Periodic samples from oil in oil pots should be sent to lab for analysis to determine Total Acid Number (TAN), water, and particle count.
Copyright WMI/L. F. 'TEX' Hildebrand 02/2003

26. Acid problems in Ammonia Refrigeration Systems
Preventative Maintenance (Cont’d).
Oil samples should always be collected adhering to a written oil sample procedure to insure accuracy and repeatability.
Periodic tests should be performed according to IIAR Bulletin 108.
Install filter in liquid ammonia lines.
Copyright WMI/L. F. 'TEX' Hildebrand 02/2003

27. Acid problems in Ammonia Refrigeration Systems
Summary
Water seriously damages the lubricating properties of oil and promotes component corrosion. Increased water concentrations indicate possible condensation, coolant leaks, or process leaks around the seals. Improper maintenance procedures may also contribute to this problem.
Copyright WMI/L. F. 'TEX' Hildebrand 02/2003

28. Acid problems in Ammonia Refrigeration Systems
Summary (Cont’d)
Organic acids, a by-product of oil oxidation, degrade oil properties and lead to corrosion of the internal components.
The Total Acid Number (TAN) is lowest as a virgin oil and can gradually increase with use.
Copyright WMI/L. F. 'TEX' Hildebrand 02/2003

29. Acid problems in Ammonia Refrigeration Systems
Summary (Cont’d)
A steady rise in the Total Acid Number (TAN) is an alarm for an oil change.
Increase in acid levels is typically caused by oil oxidation over time. However, acids generated due to contamination by-products will send the Total Acid Number (TAN) soaring in a relatively short time span.
Copyright WMI/L. F. 'TEX' Hildebrand 02/2003

30. Acid problems in Ammonia Refrigeration Systems
Summary (Cont’d)
The invasion of contaminants from the surrounding environment in the form of dirt, water, and process contamination are the leading cause of machine degradation and failure. Monitoring increased contamination should be the trigger to take action in order to save the oil and avoid unnecessary machine wear.
Copyright WMI/L. F. 'TEX' Hildebrand 02/2003

31. Acid problems in Ammonia Refrigeration Systems
Summary (Cont’d)
By identifying potential sources of contamination, it is possible to more effectively monitor the level of contaminants in the lubricating oils. Potential contaminants and sources of ingression will be identified. This will allow for proper monitoring, and specific corrective action when contamination is found.
Copyright WMI/L. F. 'TEX' Hildebrand 02/2003

32. Identification of elements in particulate matter
Copyright WMI/L. F. 'TEX' Hildebrand 02/2003

33. Acid problems in Ammonia Refrigeration Systems
Questions?
Copyright WMI/L. F. 'TEX' Hildebrand 02/2003

34. Copyright WMI/L. F. 'TEX' Hildebrand 02/2003
Thank You!
“Tex”
Copyright WMI/L. F. 'TEX' Hildebrand 02/2003