R22 polution of R717 refrigeration systems

1
R22 polution of R717 refrigeration systems

• How can it happen?
• How do R22 and R717 react in the system?
• What will be the symptoms on the system?
• How do we solve the problem if R22 gets into a
  R717 system?
• How do we avoid R22 gets into the system?

C
C
ooling M. Sc. Mech. Per
Skærbæk Nielsen, 45 28720673, 45 721990,
skaer_at_mail.dk, ww.coolingconsult.com
onsult Bjødstrupvej 77, 8310
Tranbjerg, Denmark, CVR 28445415
2
How can R22 get into a R717 refrigeration system?

• During service and maintenance
• Using the same hoses, containers, tools and
  pressure vessels when working on both R22 and
  R717 systems
• When second hand components from R22 systems are
  fitted on R717 systems
• Accidents, where the wrong refrigerant is charged
  to the system
• Direct from the supplier of refrigerant
• Supplier can use same charging system for R22 and
  R717
• Pressure vessels used for both R22 and R717
• When changing refrigerant
• Failing to get all oil and R22 out of a system
  which is changed to R717.

C
C
ooling M. Sc. Mech. Per
Skærbæk Nielsen, 45 28720673, 45 721990,
skaer_at_mail.dk, ww.coolingconsult.com
onsult Bjødstrupvej 77, 8310
Tranbjerg, Denmark, CVR 28445415
3
How do R22 and R717 react in a R717 system?
Reactions will take place where R717 is in the
liquid phase
R22 R717 gt AMMONIUM
AMMONIUM
AMMONIUM CYANIDE
CHLORIDE
FLOURIDE CHClF2 5NH3 gt NH4CN
NH4Cl 2NH4F
Will react with iron Dissolves in NH3 liquid
Colorless crystals
Colorless Very corrosive
crystals
Precipitates
C
C
ooling M. Sc. Mech. Per
Skærbæk Nielsen, 45 28720673, 45 721990,
skaer_at_mail.dk, ww.coolingconsult.com
onsult Bjødstrupvej 77, 8310
Tranbjerg, Denmark, CVR 28445415
4
Ammoniacyanide will react with iron in the system
R22 R717 IRON gt
AMMONIUM AMMONIUM
AMMONIUM HYDROGEN
FERROCYANIDE CHLORIDE
FLOURIDE 6CHClF228NH3Fe gt(NH4)4Fe(CN)6
6NH4Cl 12NH4F H2
Dissolves in Dissolves
Colorless Non- NH3
liquid. in NH3 liquid
Crystals conden- Yellow color.
Corrosive Precipitates
sible gas Color change slowly
to grey/blue when ex- posed to
air.
C
C
ooling M. Sc. Mech. Per
Skærbæk Nielsen, 45 28720673, 45 721990,
skaer_at_mail.dk, ww.coolingconsult.com
onsult Bjødstrupvej 77, 8310
Tranbjerg, Denmark, CVR 28445415
5
Ammoniumferrocyanide can react further
R22 R717 IRON gt
IRONBLUE AMMONIUM AMMONIUM
HYDROGEN CHLORIDE
FLOURIDE 18CHCLF272NH37Fe gt Fe4(Fe(CN)6)3
18NH4Cl 36NH4F 9H2
Crystals Dissolves
Colorless Non Strong
blue in NH3 liquid
crystals condens-
Precipitates Corrosive
Precipitates ible gas
C
C
ooling M. Sc. Mech. Per
Skærbæk Nielsen, 45 28720673, 45 721990,
skaer_at_mail.dk, ww.coolingconsult.com
onsult Bjødstrupvej 77, 8310
Tranbjerg, Denmark, CVR 28445415
6
How much is created?
Every kg R22 in a R717 system will create
0,62 kg AMMONIUMCHLORIDE
NH4Cl 0,86 kg AMMONIUMFLOURIDE NH4F 1
kg R22 gt AMMONIUMFERROCYANIDE
(NH4)4Fe(CN)6 IRONBLUE
Fe4Fe(CN)6 0,004-0,012 kg HYDROGEN H2
0,55 kg
C
C
ooling M. Sc. Mech. Per
Skærbæk Nielsen, 45 28720673, 45 721990,
skaer_at_mail.dk, ww.coolingconsult.com
onsult Bjødstrupvej 77, 8310
Tranbjerg, Denmark, CVR 28445415
7
Where do the reaction products settle?
AMMONIUMCHLORIDE Settles as porous crystals
where NH3 NH4Cl liquid evaporates, mainly in
expansion AMMONIUMFERROCYANIDE devices and
evaporators (NH4)4Fe(CN)6

AMMONIUMFLOURIDE Settles as crystals in the
NH3 liquid where NH4F they are created,
mainly in high pressure IRONBLUE
receiver and high pressure
liquid line. Fe4(Fe(CH6))3
HYDROGEN H2 Assembles as non condensible
gas in condenser and / or receiver
C
C
ooling M. Sc. Mech. Per
Skærbæk Nielsen, 45 28720673, 45 721990,
skaer_at_mail.dk, ww.coolingconsult.com
onsult Bjødstrupvej 77, 8310
Tranbjerg, Denmark, CVR 28445415
8
Secondary Effects
In the presense of zinc, Zincammoniumchloride
Zn(NH3)2Cl will be created Zincammoniumchloride
Zn(NH3)2Cl Have a flux effect gt reactive
surfaces on metals Ammoniumchloride Creates a
very corrosive environment NH4Cl Valves,
regulators etc. can get stuck du to excessive
corrosion.
C
C
ooling M. Sc. Mech. Per
Skærbæk Nielsen, 45 28720673, 45 721990,
skaer_at_mail.dk, ww.coolingconsult.com
onsult Bjødstrupvej 77, 8310
Tranbjerg, Denmark, CVR 28445415
9
Excessive Corrosion
Pistons from PM valves exposed in two weeks to
the corrosive environment of a R22 poluted R717
system.
C
C
ooling M. Sc. Mech. Per
Skærbæk Nielsen, 45 28720673, 45 721990,
skaer_at_mail.dk, ww.coolingconsult.com
onsult Bjødstrupvej 77, 8310
Tranbjerg, Denmark, CVR 28445415
10
Practical examples of damage on systems
Blue coloring
Blocked by corrosion
Check valves blocked
Sludge
Compressor bearing break down
Pump damage
Blue coloring
Sludge
Blue coloring
Housing filled with sludge
Blue coloring and corrosion
Big amount of sludge
Pipe blocked
Pipes and valves totally blocked
C
C
ooling M. Sc. Mech. Per
Skærbæk Nielsen, 45 28720673, 45 721990,
skaer_at_mail.dk, ww.coolingconsult.com
onsult Bjødstrupvej 77, 8310
Tranbjerg, Denmark, CVR 28445415
11
How to clean the system?
AMMONIUMCHLORIDE NH4Cl Dissolves in
water AMMONIUMFLOURIDE NH4F Dissolves in
cold water and AMMONIUMFEEROCYANIDE
decompose in hot water (NH4)4Fe(CN)6 IRONBLU
E Fe((Fe(CH6))3 Will not dissolve in
water, mechanical cleaning
necessary Corrosion products Mechanical
cleaning
C
C
ooling M. Sc. Mech. Per
Skærbæk Nielsen, 45 28720673, 45 721990,
skaer_at_mail.dk, ww.coolingconsult.com
onsult Bjødstrupvej 77, 8310
Tranbjerg, Denmark, CVR 28445415
12
Conclusions

• R22 pollution of R717 systems can happen
• The quantity of reaction products is high
• Very corrosive environments can be created in the
  plant
• Valves, filters, controls and pipes can get
  blocked
• Compressors and NH3 pumps can be damaged
• Valves and controls can get stuck in corrosion
• System cleaning difficult and expensive

C
C
ooling M. Sc. Mech. Per
Skærbæk Nielsen, 45 28720673, 45 721990,
skaer_at_mail.dk, ww.coolingconsult.com
onsult Bjødstrupvej 77, 8310
Tranbjerg, Denmark, CVR 28445415