Cathodic Protection Impressed Current
14 DES 2011
PT PERTAMINA (PERSERO)
Cathodic Protection
Impressed Current
Pelatihan Basic Electrical
Agustus 2013
CONFIDENTIAL AND PROPRIETARY
Any use of this material without specific permission of PT. Pertamina (Persero) RU.V Balikpapan
is strictly prohibited
CATHODIC PROTECTION
Cathodic Protection adalah salah satu teknik yang
digunakan untuk mengontrol korosi pada
permukaan
k
l
logam.
PERTAMINA
APA ITU KOROSI ???
• Korosi = karat = Kerusakan material dikarenakan reaksi
dengan lingkungannya.
• Karat = Zat berwarna merah kecoklatan pada
permukaan besi / baja.
• Akibat : Adanya proses elektrokimia atau fenomena
elektrikal.
Kriteria terjadinya peristiwa
korosi akibat pengaruh
elektrikal :
1. Anoda dan Katoda
2. Berada dalam media elektrolit
yang sama
3. Hubungan listrik antara anoda
dan katoda
4 Adanya O2
4.
PERTAMINA
PENDAPAT LAIN :
Korosi :
- Akibat reaksi elektrokimia
Sebab :
- Perbedaan potential pada permukaan besi/baja
KOMBINASI REAKSI “OKSIDASI” DAN “REDUKSI” =
REAKSI ‘REDOKS’
OKSIDASI :
Fe Fe2+ + 2e
x2
REDUKSI :
2H2O + O2 + 4e 4OH¯
X1
2Fe + 2H2O + O2 ----> 2Fe + 4OH¯
2Fe + 2H2O + O2 ----> 2Fe(OH)2
2Fe(OH)2 + H2O + ½ O2 ----> 2Fe(OH)3
dengan produk akhir yang disebut RUST atau KARAT
Reaksi korosi lain yang terjadi adalah terbentuknya Fe2O3
(hematit) :
3Fe(OH)2 + 2OH¯ ----> Fe3O4 + 4 H2O
2Fe3O4 + 2OH¯ ----> 3Fe2O3 + H2O
PERTAMINA
KERUGIAN AKIBAT KOROSI
Kerugian karena korosi pada banyak
instalasi besi baja yang “rusak”
PERTAMINA
• Akibat Langsung
Kerugian di USA pada tahun 1975
adalah US$ 70 billion atau 3 – 5%
d i GNP karena
dari
k
k
kerusakan
k
material.
Dikutip dari “National Bureau of Standard & Battele
Columbus Laboratorium in 1975”.
• Akibat Tidak Langsung
* Kematian dan kecelakaan.
kecelakaan
* Produksi yang berkurang.
* Plant shut down.
* Over design
design.
* Kontaminasi produk.
* Kerusakan lingkungan.
METODA PENCEGAHAN
KOROSI
Penyelidikan pencegahan korosi diantaranya oleh :
National Association of Corrosion Engineers (NACE)
Federation of Societies for Paint Technology
Steel Structure Painting Council (SSPC)
Dll.
Metoda antara lain :
a Protective Coating
a.
b. Cathodic Protection
APA ITU CATHODIC PROTECTION ?
CATHODIC PROTECTION adalah :
Proses pencegahan karat / korosi yang
memanfaatkan proses / peristiwa korosi
itu sendiri.
sendiri
CATHODIC PROTECTION didapat dengan 2 cara :
1. SACRIFICIAL ANODE SYSTEM
2 IMPRESSED CURRENT SYSTEM
2.
CATHODIC PROTECTION
SISTEM PERLINDUNGAN KATODIK
Cara bekerja :
Mengubah potensial permukaan besi / baja menjadi katoda
Arus proteksi luar yang menekan / menahan arus keluar
D
Daerah
h katoda
k t d
Korosi stop
Mg -1.50
SACRIFICIAL SYSTEM
PERTAMINA
PRINCIPLES OF
CORROSION
Dimana 2 atau lebih metal yang terhubung
electrically, salah satu metal akan
cenderung terkorosi terhadap metal
lainnya.
Metal yang terletak di atas akan cenderung
terkorosi dan akan melindungi metal di
bawahnya.
Contoh:
Cooper dan Zinc terhubung satu sama lain,
Zinc akan terkorosi sehingga akan
memproteksi Copper.
Corrosion rate tergantung
g
gp
pada relative area
antara anode dan cathode.
PERTAMINA
TABEL DERET VOLTA
CONTOH PEMASANGAN SACRIFICIAL ANODE SYSTEM
PERTAMINA
IMPRESSED CURRENT SYSTEM
Impressed Current Anodes
a)
Impressed current anodes must be able to pass d.c. current with
negligible metal loss
b)
Steel will lose 9kg per amp year.
c)
Impressed current anodes cause electrolysis of water and only a
few materials are suitable for this application.
2H2O 4H+ + ½O2 + 4e
d)
In sea water chlorine evolution will also take place
2Cl- ½ Cl2 + 2e
Anodes
• Platinised Titanium
a)
Inert Titanium substrate coated with 2.5, 5 or even 7.5 microns
of platinum.
b)
Can operate at high current densities in the range 100 to 5000
Am-2.
c)
Low consumption rate of 10 mg per amp per year.
d) Long Life if left energised, if not energised for 3 to 6 months
failure of the anode can occur.
e) Limited operating voltages in seawater (12V)
f) Need to be of robust construction when used on jetties
Other Anode Materials
• Silicon Iron Chrome
▫ These are extremely brittle materials
▫ Operate at low current densities 10 to 40 Am
Am-2
2
▫ Consumption rate 0.2 to 0.5 kg A-1y-1
▫ Cheap and proven track record
• Magnetite
▫ These are light and brittle
▫ Quite expensive
▫ Low consumption rate
▫ Relatively new anode material
• L
Lead
d Sil
Silver
▫ Only used in seawater
▫ Used for ships cathodic protection systems only
TYPES OF REFERENCE ELECTRODE
• Copper/Copper Sulphate (Cu/CuSO4 ) (For onshore
cathodic protection systems only)
• Zinc
• Silver/Silver Chloride/Seawater (Ag/AgCl)
• Specialist electrodes for cathodic protection in concrete
laboratory
y testing
g e.g.
g calomel and hydrogen
y g electrode
GROUNDBED
TRANSFORMER
RECTIFIER
+
M28 TEST
POST
C.P.
TEST
CABLE
FIGURE 3
PROTECTED PIPE
POWER IMPRESSED CATHODIC PROTECTION
SYSTEM ELECTRICAL CIRCUIT.
Effectivitas Cathodic Protection
Menurut NACE Standard :
Most commonly accepted criteria if
a negative potential of at least
0.85 volt ( or More negative )
as measured between structure
surface and saturated copper /
copper sulfate reference
electrode in contact with
electrolyte
PERTAMINA
Effectivitas Cathodic Protection
Menurut BS 7361 Part 1 : Minimum protection criteria for Cathodic Protection.
•
If the structure to seawater p
potential is more negative
g
than -850mV vs a Cu/CuSO4
electrode (or -800mV vs an Ag/AgCl) then full levels of cathodic protection are
achieved in an aerobic environment.
•
If the structure to seawater p
potential is more negative
g
than -950mV vs a Cu/CuSO4
electrode (-900 mV vs an Ag/AgCl electrode) then full levels of cathodic protection
are achieved in an anaerobic environment.
•
The maximum level of potential is determined by the structure coating Cathodic
Disbondment of the coating can occur if a high negative potential is applied.
•
The maximum negative potential is -1.10 to -1,15V vs Ag/AgCl. There is also the
possibility of hydrogen embrittlement.
embrittlement
POT
TENTIAL
vs C
Cu/CuSO4
POT
TENTIAL
vs A
Ag/AgCl
POT
TENTIAL
vs Z
ZINC IN
SEA
AWATER
-0.5
-0.45 + 0.6
-0.6
06
-0.7
-0.8
-0.9
-1.0
-1.1
INTENSE CORROSION
FREELY CORRODING
SOME PROTECTION
ZONE OF CATHODIC PROTECTION
SOME OVERPROTECTION
INCREASED OVERPROTECTION
-1.2
-1.3
-1.4
-0.55
0 55 + 0.5
05
-0.65 + 0.4
-0.75 + 0.3
-0.85 + 0.2
-0.95 + 0.1
-1.05 + 0.0
-1.15 -0.1
PRODUCING BLISTERING OF PAINTS
AND SPALLING
INCREASING DANGER OF
EMBRITTLEMENT
-1.25 -0.2
-1.35 -0.3
THE RELATIONSHIP BETWEEN THE
CORROSION/CATHIODIC PROTECTION
BEHAVIOUR OF A STEEL STRUCTURE
AND ITS POTENTIAL
Stray Current
TYPICAL STRAY CURRENT
SYSTEM.
Summary of Typical Maintenance Requirements Extracted
from BS 7361: Impressed Current CP Systems
Test Frequency:
Test Description
Every 3 Months
1.
At maximum intervals of 3 months check
satisfactory operation of transformers rectifiers.
the
Rectifier output voltages and currents should be
recorded and pipe to soil potential recorded at the
extremities of the pipeline and at test facilities midway
between the transformer
f
rectifier
f
locations.
Test Frequency:
Test Description
Every 12 Months
1.
At maximum intervals of 12 months the pipe to soil
potential should be recorded at all measuring locations
and at other locations where a low potential has been
recorded.
2.
Potentials on secondary structures bonded into the CP
system or with sacrificial anodes fitted should be
recorded.
3
3.
All transformer rectifiers and test facilities should be
checked for serviceability and repair.
PERTAMINA
Summary of Typical Maintenance Requirements Extracted
from BS 7361: Impressed Current CP Systems
Test Frequency:
Test Description
Every 5 to 10 years
1.
Close interval potential surveys should be conducted.
These tests are primarily concerned with impressed
current systems but should also be considered for
sacrificial anode systems.
2.
Repeat interference testing.
3
3.
B di
Bonding
checks.
h k
Annual
▪ Carryy out tests normallyy carried out at monthlyy and six monthlyy intervals.
▪ Carry out Electrical Performance Tests on Transformer Rectifiers to comply with
BS 7671.
Specialist Checks Inspection Frequency to be agreed
▪ Check condition of all reference electrode, anode and bonding cable connections
from surface.
▪ Check underwater condition of anodes/reference electrodes.
▪ Carry
C
outt potential
t ti l survey off allll piles
il tto confirm
fi iinter-pile
t
il b
bonding.
di
PERTAMINA
Aplication
p
and Design
g :
• Pipelines and Plants
• Heat Exchangers
• Tanks
• Water Screens
• Marine Structures
• Shipping
• Petro Chemical Plant
PERTAMINA
CONTOH APLIKASI CATHODIC PROTECTION
PERTAMINA
IMPRESSED CURRENT SYSTEM FOR PIPELINE
System
: Impressed current using shallow ground bed
Material
: Ferro Silicon Chromium (Fe/Si/Cr) Anode
PERTAMINA
IMPRESSED CURRENT SYSTEM FOR PIPELINE
System
: Impressed current semi deep well ground bed
Material
: Mixed Metal Oxide (MMO) Anode
PERTAMINA
SACRIFICIAL SYSTEM FOR PIPELINE
System
: Sacrificial
Material
: Magnesium Anode
PERTAMINA
IMPRESSED CURRENT SYSTEM FOR JETTY
System
: Impressed current
M t i l
Material
: Platinised
Pl ti i d Titanium
Tit i
(Pt/Ti) Anode
A d
PERTAMINA
IMPRESSED CURRENT SYSTEM FOR JETTY
System
: Impressed current
Material
: Platinised Titanium (Pt/Ti) Anode
PERTAMINA
SACRIFICIAL SYSTEM FOR JETTY
System
Material
: Sacrificial
: Aluminium Anode
PERTAMINA
Rusted Structure : Jetty Splash Zone, Pipeline
PERTAMINA
Rusted Structure
: Jetty
y Splash
p
Zone
SPLASH GUARD WRAPPING SYSTEM FOR JETTY
PERTAMINA
PERTAMINA
PT PERTAMINA (PERSERO)
Cathodic Protection
Impressed Current
Pelatihan Basic Electrical
Agustus 2013
CONFIDENTIAL AND PROPRIETARY
Any use of this material without specific permission of PT. Pertamina (Persero) RU.V Balikpapan
is strictly prohibited
CATHODIC PROTECTION
Cathodic Protection adalah salah satu teknik yang
digunakan untuk mengontrol korosi pada
permukaan
k
l
logam.
PERTAMINA
APA ITU KOROSI ???
• Korosi = karat = Kerusakan material dikarenakan reaksi
dengan lingkungannya.
• Karat = Zat berwarna merah kecoklatan pada
permukaan besi / baja.
• Akibat : Adanya proses elektrokimia atau fenomena
elektrikal.
Kriteria terjadinya peristiwa
korosi akibat pengaruh
elektrikal :
1. Anoda dan Katoda
2. Berada dalam media elektrolit
yang sama
3. Hubungan listrik antara anoda
dan katoda
4 Adanya O2
4.
PERTAMINA
PENDAPAT LAIN :
Korosi :
- Akibat reaksi elektrokimia
Sebab :
- Perbedaan potential pada permukaan besi/baja
KOMBINASI REAKSI “OKSIDASI” DAN “REDUKSI” =
REAKSI ‘REDOKS’
OKSIDASI :
Fe Fe2+ + 2e
x2
REDUKSI :
2H2O + O2 + 4e 4OH¯
X1
2Fe + 2H2O + O2 ----> 2Fe + 4OH¯
2Fe + 2H2O + O2 ----> 2Fe(OH)2
2Fe(OH)2 + H2O + ½ O2 ----> 2Fe(OH)3
dengan produk akhir yang disebut RUST atau KARAT
Reaksi korosi lain yang terjadi adalah terbentuknya Fe2O3
(hematit) :
3Fe(OH)2 + 2OH¯ ----> Fe3O4 + 4 H2O
2Fe3O4 + 2OH¯ ----> 3Fe2O3 + H2O
PERTAMINA
KERUGIAN AKIBAT KOROSI
Kerugian karena korosi pada banyak
instalasi besi baja yang “rusak”
PERTAMINA
• Akibat Langsung
Kerugian di USA pada tahun 1975
adalah US$ 70 billion atau 3 – 5%
d i GNP karena
dari
k
k
kerusakan
k
material.
Dikutip dari “National Bureau of Standard & Battele
Columbus Laboratorium in 1975”.
• Akibat Tidak Langsung
* Kematian dan kecelakaan.
kecelakaan
* Produksi yang berkurang.
* Plant shut down.
* Over design
design.
* Kontaminasi produk.
* Kerusakan lingkungan.
METODA PENCEGAHAN
KOROSI
Penyelidikan pencegahan korosi diantaranya oleh :
National Association of Corrosion Engineers (NACE)
Federation of Societies for Paint Technology
Steel Structure Painting Council (SSPC)
Dll.
Metoda antara lain :
a Protective Coating
a.
b. Cathodic Protection
APA ITU CATHODIC PROTECTION ?
CATHODIC PROTECTION adalah :
Proses pencegahan karat / korosi yang
memanfaatkan proses / peristiwa korosi
itu sendiri.
sendiri
CATHODIC PROTECTION didapat dengan 2 cara :
1. SACRIFICIAL ANODE SYSTEM
2 IMPRESSED CURRENT SYSTEM
2.
CATHODIC PROTECTION
SISTEM PERLINDUNGAN KATODIK
Cara bekerja :
Mengubah potensial permukaan besi / baja menjadi katoda
Arus proteksi luar yang menekan / menahan arus keluar
D
Daerah
h katoda
k t d
Korosi stop
Mg -1.50
SACRIFICIAL SYSTEM
PERTAMINA
PRINCIPLES OF
CORROSION
Dimana 2 atau lebih metal yang terhubung
electrically, salah satu metal akan
cenderung terkorosi terhadap metal
lainnya.
Metal yang terletak di atas akan cenderung
terkorosi dan akan melindungi metal di
bawahnya.
Contoh:
Cooper dan Zinc terhubung satu sama lain,
Zinc akan terkorosi sehingga akan
memproteksi Copper.
Corrosion rate tergantung
g
gp
pada relative area
antara anode dan cathode.
PERTAMINA
TABEL DERET VOLTA
CONTOH PEMASANGAN SACRIFICIAL ANODE SYSTEM
PERTAMINA
IMPRESSED CURRENT SYSTEM
Impressed Current Anodes
a)
Impressed current anodes must be able to pass d.c. current with
negligible metal loss
b)
Steel will lose 9kg per amp year.
c)
Impressed current anodes cause electrolysis of water and only a
few materials are suitable for this application.
2H2O 4H+ + ½O2 + 4e
d)
In sea water chlorine evolution will also take place
2Cl- ½ Cl2 + 2e
Anodes
• Platinised Titanium
a)
Inert Titanium substrate coated with 2.5, 5 or even 7.5 microns
of platinum.
b)
Can operate at high current densities in the range 100 to 5000
Am-2.
c)
Low consumption rate of 10 mg per amp per year.
d) Long Life if left energised, if not energised for 3 to 6 months
failure of the anode can occur.
e) Limited operating voltages in seawater (12V)
f) Need to be of robust construction when used on jetties
Other Anode Materials
• Silicon Iron Chrome
▫ These are extremely brittle materials
▫ Operate at low current densities 10 to 40 Am
Am-2
2
▫ Consumption rate 0.2 to 0.5 kg A-1y-1
▫ Cheap and proven track record
• Magnetite
▫ These are light and brittle
▫ Quite expensive
▫ Low consumption rate
▫ Relatively new anode material
• L
Lead
d Sil
Silver
▫ Only used in seawater
▫ Used for ships cathodic protection systems only
TYPES OF REFERENCE ELECTRODE
• Copper/Copper Sulphate (Cu/CuSO4 ) (For onshore
cathodic protection systems only)
• Zinc
• Silver/Silver Chloride/Seawater (Ag/AgCl)
• Specialist electrodes for cathodic protection in concrete
laboratory
y testing
g e.g.
g calomel and hydrogen
y g electrode
GROUNDBED
TRANSFORMER
RECTIFIER
+
M28 TEST
POST
C.P.
TEST
CABLE
FIGURE 3
PROTECTED PIPE
POWER IMPRESSED CATHODIC PROTECTION
SYSTEM ELECTRICAL CIRCUIT.
Effectivitas Cathodic Protection
Menurut NACE Standard :
Most commonly accepted criteria if
a negative potential of at least
0.85 volt ( or More negative )
as measured between structure
surface and saturated copper /
copper sulfate reference
electrode in contact with
electrolyte
PERTAMINA
Effectivitas Cathodic Protection
Menurut BS 7361 Part 1 : Minimum protection criteria for Cathodic Protection.
•
If the structure to seawater p
potential is more negative
g
than -850mV vs a Cu/CuSO4
electrode (or -800mV vs an Ag/AgCl) then full levels of cathodic protection are
achieved in an aerobic environment.
•
If the structure to seawater p
potential is more negative
g
than -950mV vs a Cu/CuSO4
electrode (-900 mV vs an Ag/AgCl electrode) then full levels of cathodic protection
are achieved in an anaerobic environment.
•
The maximum level of potential is determined by the structure coating Cathodic
Disbondment of the coating can occur if a high negative potential is applied.
•
The maximum negative potential is -1.10 to -1,15V vs Ag/AgCl. There is also the
possibility of hydrogen embrittlement.
embrittlement
POT
TENTIAL
vs C
Cu/CuSO4
POT
TENTIAL
vs A
Ag/AgCl
POT
TENTIAL
vs Z
ZINC IN
SEA
AWATER
-0.5
-0.45 + 0.6
-0.6
06
-0.7
-0.8
-0.9
-1.0
-1.1
INTENSE CORROSION
FREELY CORRODING
SOME PROTECTION
ZONE OF CATHODIC PROTECTION
SOME OVERPROTECTION
INCREASED OVERPROTECTION
-1.2
-1.3
-1.4
-0.55
0 55 + 0.5
05
-0.65 + 0.4
-0.75 + 0.3
-0.85 + 0.2
-0.95 + 0.1
-1.05 + 0.0
-1.15 -0.1
PRODUCING BLISTERING OF PAINTS
AND SPALLING
INCREASING DANGER OF
EMBRITTLEMENT
-1.25 -0.2
-1.35 -0.3
THE RELATIONSHIP BETWEEN THE
CORROSION/CATHIODIC PROTECTION
BEHAVIOUR OF A STEEL STRUCTURE
AND ITS POTENTIAL
Stray Current
TYPICAL STRAY CURRENT
SYSTEM.
Summary of Typical Maintenance Requirements Extracted
from BS 7361: Impressed Current CP Systems
Test Frequency:
Test Description
Every 3 Months
1.
At maximum intervals of 3 months check
satisfactory operation of transformers rectifiers.
the
Rectifier output voltages and currents should be
recorded and pipe to soil potential recorded at the
extremities of the pipeline and at test facilities midway
between the transformer
f
rectifier
f
locations.
Test Frequency:
Test Description
Every 12 Months
1.
At maximum intervals of 12 months the pipe to soil
potential should be recorded at all measuring locations
and at other locations where a low potential has been
recorded.
2.
Potentials on secondary structures bonded into the CP
system or with sacrificial anodes fitted should be
recorded.
3
3.
All transformer rectifiers and test facilities should be
checked for serviceability and repair.
PERTAMINA
Summary of Typical Maintenance Requirements Extracted
from BS 7361: Impressed Current CP Systems
Test Frequency:
Test Description
Every 5 to 10 years
1.
Close interval potential surveys should be conducted.
These tests are primarily concerned with impressed
current systems but should also be considered for
sacrificial anode systems.
2.
Repeat interference testing.
3
3.
B di
Bonding
checks.
h k
Annual
▪ Carryy out tests normallyy carried out at monthlyy and six monthlyy intervals.
▪ Carry out Electrical Performance Tests on Transformer Rectifiers to comply with
BS 7671.
Specialist Checks Inspection Frequency to be agreed
▪ Check condition of all reference electrode, anode and bonding cable connections
from surface.
▪ Check underwater condition of anodes/reference electrodes.
▪ Carry
C
outt potential
t ti l survey off allll piles
il tto confirm
fi iinter-pile
t
il b
bonding.
di
PERTAMINA
Aplication
p
and Design
g :
• Pipelines and Plants
• Heat Exchangers
• Tanks
• Water Screens
• Marine Structures
• Shipping
• Petro Chemical Plant
PERTAMINA
CONTOH APLIKASI CATHODIC PROTECTION
PERTAMINA
IMPRESSED CURRENT SYSTEM FOR PIPELINE
System
: Impressed current using shallow ground bed
Material
: Ferro Silicon Chromium (Fe/Si/Cr) Anode
PERTAMINA
IMPRESSED CURRENT SYSTEM FOR PIPELINE
System
: Impressed current semi deep well ground bed
Material
: Mixed Metal Oxide (MMO) Anode
PERTAMINA
SACRIFICIAL SYSTEM FOR PIPELINE
System
: Sacrificial
Material
: Magnesium Anode
PERTAMINA
IMPRESSED CURRENT SYSTEM FOR JETTY
System
: Impressed current
M t i l
Material
: Platinised
Pl ti i d Titanium
Tit i
(Pt/Ti) Anode
A d
PERTAMINA
IMPRESSED CURRENT SYSTEM FOR JETTY
System
: Impressed current
Material
: Platinised Titanium (Pt/Ti) Anode
PERTAMINA
SACRIFICIAL SYSTEM FOR JETTY
System
Material
: Sacrificial
: Aluminium Anode
PERTAMINA
Rusted Structure : Jetty Splash Zone, Pipeline
PERTAMINA
Rusted Structure
: Jetty
y Splash
p
Zone
SPLASH GUARD WRAPPING SYSTEM FOR JETTY
PERTAMINA
PERTAMINA