external & internal corrosion monitoring

1. inthenameofalmightyAllah,themostmerciful and
beneficent

2. MEMBER
Name: sairalikhan
Course: CPLevel-01

3. PROJECT TITLE
What is corrosion protection and
corrosion control monitoring techniques?

4. PROJECT OVERVIEW
 OBJECTIVE:
The objective of this project is to transfer the
crude oil from extraction point to the use
point via pipeline based CPS.
CC is for supervisory control and monitoring of the internal
side of pipe lines parameters corrosion.

5. BLOCK DIAGRAM
CP
CIPS
PSP PCM
CC
COUPONS
PROBESRA

6. CATHODIC PROTECTION SYSTEM
Cathodic protection (CP) is a method of corrosion control that can
be applied to buried and submerged metallic structures.
In most cases, effective corrosion protection & control
of metals is obtained by combining two or more of
these methods.
Corrosion protection should be considered at the
design stage of a given facility or system.
Cathodic protection in its classical form cannot be
used to protect surfaces exposed to the atmosphere.
The use of anodic metallic coatings such as zinc on
steel (galvanizing).
First method, cathodic protection with galvanic
anodes.

7.  G.A uses the corthe rosion of an active metal, such as magnesium or zinc, to
provide required electrical current.
 This method, called sacrificial or galvanic anode cathodic.
 In the second method, impressed current cathodic protection.
 D.C current used to provide electrical current.
It is normally used in conjunction with coatings and can be
considered as a secondary corrosion control technique.
 The primary corrosion control method on any given structure is
normally a coating system which can be between 50 and 99 %
efficient depending upon age, type, method of installation.

8. Fig.

9. Underground metals

10. Fig.

11. MONITORING OF CPS
Close Interval Potential Survey (CIPS)
PipeTo Soil Potential (PSP)
Pipe Current Mapper (PCM)

12. Close interval survey is a survey method to provide detailed
information on the potential difference between the pipeline and the
soil.
CIPS is external corrosion of buried pipelines is made using pipe-to-
soil potential measurements.
 The Close Interval Potential Survey (CIPS) technique is aimed at
assessing the CP effectiveness over the entire length of the pipeline,
in between the permanent test stations.

13. CIPS are usually measured at fixed test points spaced between 1-5
km along a pipeline.
CIPS spacing depending on client requirement.
CIPS is reliable information about the CP status elsewhere along
the pipeline.
CIPS test points indicate favorable data.
If the distance between the test points is decreased, the survey
will provide more accurate data about CP conditions along the
pipeline.

14. Cathodically protected pipelines are equipped with permanent test
stations where electronic leads are attached to the pipeline to
measure the pipe-to-soil potential.
 The potentials measured at permanent test stations only
originate from a small fraction of the total pipeline length.
 One proposed rule of thumb estimates that the measured
potential is associated with a relatively short length of pipeline -
about 2x the depth of pipeline burial.
 CIPS overcomes such problems by automatically recording,
storing, calculating and displaying measurement data.

15. Fig. 1

16. Fig. 2

17. Advantages Of CIPS
 Simple in principle and widely used.
 Assessment extends along the entire
length of the pipeline.
 Complete pipeline right-of-way can be
inspected as part of the walk along the
pipeline.

18. Pipeline Current Mapper System (PCM)
 The PCM+ Pipeline Current Mapper System by
Radiodection consists of a portable transmitter
and a hand-held receiver.
 The transmitter is connected at the CPS station
and applies a special signal to the pipeline.
 The receiver locates this signal at distances up to
30 km (19 miles) to identify the position and
depth of the pipe.

19.  The PCM and its accessory equipment provide any
pipeline technician with the latest in accurate.
 Fast and reliable pipeline current mapping tools.
 The location and measurement of pipeline corrosion
using electromagnetic detection devices (Locators)
must be linked with GIS (geographic information system)
and GPS (Global Positioning System) to provide an
accurate record of the condition of pipes and the
position and time coordinates for post-mapping
analysis.

20.  This requirement is the basis of the PCM,
which enables the pipeline technician to
identify corrosion at an earlier stage and carry
out preventative maintenance on pipelines to
give them a longer life.

21. Radiodection Fig.

22. Fig.

23. About Radiodection
• PCM+ Receiver features Precision
locator and PCM in one unit
• Unique features to improve data integrity
(ASA, ACD, AGC, Depth of Cover)
• Quicker 3 second ACCA mapping
• Record up to 1000 data records
• Real time upload of mapped data via
Bluetooth to PDA or PC, also Integrates
GPS data
• Downloadable analysis software for PDA
and PC

24. • Integrates with standard GIS
software
• 5key graph mapping modes
including locate depth, current and
phase
• Low power for full day survey
• Backlight / Real sound
• High power 150 Watt
• 19 mile range @ 4Hz

25. Fig.

26. Quickly locate and measure
pipeline coating faults
 The location and measurement of pipeline
corrosion using electromagnetic detection
devices (Locators) are increasingly being linked
with GIS systems and GPS information, to
provide an accurate record of the condition of
pipes and the position and time co-ordinates for
post mapping analysis - this requirement is the
basis of the PCM+.

27. Uses Of PCM
 The PCM+ uses a powerful feature set consisting of Automatic
Signal Attenuation (ASA), Advanced Current Direction (ACD) and
Adaptive Ground Compensation (AGC).
 The Pipeline Current Mapper (PCM) is used to conduct an ACCA
(Alternating Current Coating Attenuation) survey.
 The PCM utilizes a signal current that measures current
attenuation characteristics along with pipeline faults to other
buried metallic structures.
 Typically, a signal current is place on the pipeline at a rectifier.
 Over the length of the pipe the current is measured and charted.

28. Fig.

29.  pipe-to-soil potential
 The pipe-to-soil potential test has been established by corrosion engineers as a
standard measurement technique in the evaluation of corrosion control and the
degree of cathodic protection applied to buried metallic structures.
 The copper sulphate half cell electrode used to contact the soil.
 PSP measured between the pipeline and a reference electrode.
 Unprotected buried steel will vary -0.30 to -0.80 volts.
 The galvanic currents will flow through the soil between the anodic and the
cathodic points.

30.  If pipe-to-soil potentials along a pipeline were of equal values.
 Galvanic currents could not flow.
 No corrosion.
GC:
Galvanic current occurs in the presence of two or more dissimilar
metals in an electrolyte or saltwater environment.
 Galvanic current is also known as electro galvanism.

31. Fig.

32. Fig.

33. PSP Example
 For example, if the open circuit pipe-to-soil potential of
an anodic point is -0.65 volt, then corrosion will be
stopped if the potential of the cathodic point(s) is made
more negative and equal to this value.
 This is a basic criterion for the cathodic protection of a
buried structure.
 However, it would be impractical and almost impossible
to determine the open circuit potential values and points
of potential equalization along a pipeline, so corrosion
engineers have established a second and more practical
criterion for adequate cathodic protection.

34.  It is generally accepted by the corrosion engineers that a
structure will be under complete cathodic protection if
the pipe-to-soil potential at all points on that structure is
maintained at a minimum level of -0.85 volt.
 This value represents over-protection in most instances,
since the points of potential equalization, as pointed out
above, is usually less negative than -0.80 volt.
 This is the most practical and economical criterion to
consider in testing for the existence of corrosion on any
buried and coated pipeline.

35. PSP Testing
 To make a pipe-to-soil test observation.
 Lead wire attached to the copper sulphate.
 Electrode is attached to the positive (+) post of the meter.
 A wire attached to the negative (-) post of the meter is
attached solidly to the pipe at any convenient point.
 This contact can be made by clipping directly to an above-
ground valve, fitting, riser, or even by attaching to a probe
bar pushed into the ground to contact the pipe.

36. PSP Observation
 Pipe-to-soil observations should be made whenever there
is any question or any doubt that the structure may not
be under full cathodic protection.
 It is desirable to practice the of pipe-to-soil potentials at
regular, say, six-month intervals to have assurance that no
physical changes had previously been made that would
upset the balance of the cathodic protection circuit.
 This is for confirmation purposes, and to discover any
changed condition which could result in corrosion
damage to the structure.

37. Corrosion Control
 Corrosion causes damages and loss of property if
they have not controlled properly.
Monitoring of corrosion control:
 Corrosion coupons.
 Probes (electrical probes).
 Residual analysis.

38. Corrosion Coupons
 Corrosion Coupos or Weight Loss technique.
 Coupons are the primary techniques used for monitoring.
 The is the best known and simplest of all corrosion
monitoring techniques.
 The method involves exposing a specimen of material
(the coupon) to a process environment for a given
duration, then removing the specimen for analysis.
 The basic measurement which is determined from
corrosion coupons is weight loss; the weight loss taking
place over the period of exposure being expressed as
corrosion rate.

39.  A specimen of test material to be used in a corrosion
test.
 Usually a metal strip or ring shaped to fit into a
testing cell or between joints of drill pipe.
 Rings, or coupons, are weighed before and after
exposure, and weight loss is measured.
 They are also examined for pits and cracks.
 Corrosion products are analyzed to define the type of
corrosion reaction.

40. Fig.

41. Coupon after exposure to corrosive environment
 Fig

42.  Metal Samples can make coupons in any size, shape, or
material you need.
 Coupons can be stenciled with alloy and sequence numbers
for proper identification.
 Monitoring program, coupons are exposed for a 90-day.
 Duration before being removed for a laboratory analysis.
 This gives basic corrosion rate measurements at a frequency
of four times per year.
 Therefore, coupon monitoring is most useful in
environments where corrosion rates do not significantly
change over long time periods.

43. Advantages of Coupons
 Advantages of weight loss coupons are that:
 The technique is applicable to all environments - gases,
liquids, solids/particulate flow.
 Visual inspection can be undertaken.
 Corrosion deposits can be observed and analyzed.
 Weight loss can be readily determined and corrosion rate
easily calculated.
 Localized corrosion can be identified and measured.
 Inhibitor performance can be easily assessed.

44. Probes (Electrical Reistance)
 ER probes can be thought of as "electronic" corrosion
techniques.
 Electrical resistance probes are the primary techniques
used for monitoring.
 The electrical resistance (ER) technique is an "on-line"
method of monitoring the rate of corrosion and the
extent of total metal loss for any metallic equipment or
structure.
 The ER technique measures the effects of both the
electrochemical and the mechanical components of
corrosion such as erosion or cavitation.

45.  It is the only on-line, instrumented technique applicable to
virtually all types of corrosive environments.
 The probe is electrically connected to the pipeline.
 ER probes provide a basic measurement of metal loss.
 Probe elements are made of a material similar to that of
pipeline.
 ER Probes are the most flexible of the electronic probes in
terms of their possible application.

46. Fig.

47.  Principles of Operation:
 The action of corrosion on the surface of the
element produces a decrease in its cross-
sectional area with a corresponding increase in
its electrical resistance.
 The increase in resistance can be related directly
to metal loss and the metal loss as a function of
time is by definition the corrosion rate.

48.  The electrical resistance of a metal or alloy
element is given by:
R= r. L/A
 where:
 L = Element length
A = Cross sectional area
r = Specific resistance

49. Examples
 Examples of situations where the ER
approach is useful are:
• Oil/gas production and transmission systems
• Refinery/petrochemical process streams
• External surfaces of buried pipelines
• Feed water systems
• Flue gas stacks
• Architectural structures

50. Fig.

51.  Before after

52.  ER Sensing Elements:
 Sensing elements are available in a variety of geometric
configurations, thicknesses, and alloy materials. Available
element types are shown in Figure .
 Metal Samples manufactures electrical resistance probes
for corrosion monitoring in wire loop, tube loop, flush-
mount, and cylindrical element.
 Wire & Tube Loop:
 Wire and tube loop elements are Teflon or glass sealed.

53.  Cylindrical:
 Cylindrical elements are supplied in all-welded form.
 Flush-Mount:
 Flush-mount elements can be provided with either glass or
epoxy seals.
 Strip:
 Strip elements are commonly used in underground probes to
monitor the effectiveness of cathodic protection currents
applied to the external surfaces of buried structures.

55. ER Probes Advantages
 ER probes advantages They are applicable to all working
environments gases, liquids, solids, particulate flows.
 Direct corrosion rates can be obtained.
 Probe remains installed in-line until operational life has
been exhausted.
 They respond quickly to corrosion upsets and can be used
to trigger an alarm.

56. Uses Of Probes
 Electrical resistance (ER) corrosion probes are commonly
used in petroleum, chemical processing, and other
environments where on-line corrosion rate readings are
required.
 Electrical resistance probes can be used in conductive
systems, as well as non-conductive environments such as
oil, gas, and atmosphere.

57. Residual Analysis
 Corrosion inhibitors are used to protect oil and gas
pipelines made of carbon steel that transport CO2 or H2S
containing wet hydrocarbons.
 The analysis of residual corrosion inhibitor concentration
in production waters has been used for years to monitor
the corrosion protection of oilfield systems.
 The utility of an analytical procedure depends on the
speed, accuracy, sensitivity, selectivity and precision of
the method.
 As the oilfields age, the water production volume
increases while the oil production goes down.

58.  The decreasing oil revenue, the cost of corrosion control
becomes disproportionately high resulting in demands for
lower cost of chemicals and services by the operating
company.
 Therefore, for a given corrosion inhibitor dosage, there is a
need to determine the amounts of the active components
present in the water and those in the oil phase as well as any
loss to the solid surfaces.
 48% internal corrosion occurs in pipeline.

60. NACE -96344 residual analyses
 The paper describes the development of a fully
automated instrumental procedure for testing residual
corrosion inhibitors in production waters in the field.
 Initial investigations were conducted in the laboratory to
evaluate the suitability of ultraviolet and fluorescence
spectrophotometric techniques to different of corrosion
inhibitors.
 Parameters for comparison included selectivity,
sensitivity, speed, accuracy and precision of the methods
under flowing conditions as in high performable liquid
chromatography and as encountered in stand alone
instruments.

61.  For the field, the number of personnel, technical
experience and proximity of the district Laboratory to the
various leases were additional factors that were
considered.
 Although the development work included most of the
nitrogen containing corrosion inhibitors (quaternary
amines, imidazole’s, amides, etc.), the procedure for
quaternary amines is used as the example and presented
in detail.

62. 
 ThE EnD
 THANKS