Corrosion/Erosion

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Corrosion/Erosion

• PROCESS OUT OF CONTROL

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Corr Science

• Corr Science, is a Alberta based company which
  supplies corrioson, erosion, and MIC products for
  pipelines and plants

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Why? Process out of control

• To provide information on the interrelation
  between Corrsion/ Erosion/ MIC proccess and
  operating variables to allow more efficient use
  of the plant or pipline
• To provide information that may be used to
  prevent a safety failure and or a potential
  disaster

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Definitions

• Corrosion
• Chemically induced wall loss
• Erosion
• Mechanically induced wall loss
• MMC
• Biologically induced wall loss (bugs)

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Corrosion Perceptions

• No one Corrosion monitoring tool can solve your
  Corrosion problem
• You will often need a combination of monitoring
  techniques to properly identify a problem area

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Corrosion Monitoring Techniques

• Electrochemical Methods
• Electrical Resistance Monitoring (ER)
• Linear Polarization Resistance Monitoring (LPR)
• Hydrogen Monitoring
• Weight Loss Coupons
• Non-Destructive Testing Techniques (NDT)
• Analytical Techniques

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Electrochemical Methods

• Electrical Resistance Monitoring (ER)
• Linear Polarization Resistance Monitoring (LPR)
• Galvanic Monitoring, aslo known as Zero
  Resistance Ammetry

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Electrical Resistance Monitoring (ER)

• The Action of corrosion on the elements serves to
  decrease the cross section area thereby
  increasing the Electrical Resistance
• The major advantage is its ability to measure
  corrosion in any environment, liquid, gas or
  particle streams

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Electrical Resistance Monitoring (ER)

• The difference between ER and electrochemical
  techniques is that ER measurements prodie
  information on the totaal loss of material, which
  ever electrochemical techniques given rate
  information

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Linear Polarization Resistance Monitoring (LPR)

• LPR measures the corrosion current flowing
  between anodic and cathodic half cells
• LPR monitoring provides an instanteous measure of
  corrosion rate and may, for example be usedas a
  method for optimising corrosion inhibitor
  injection

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Galvanic Monitoring(Zero Resistance Ammetry ZRA)

• ZRA probes, two electrodes of dissimilar metals
  are exposed to the process fluid. When immersed
  in solution, a natural voltage (potential)
  difference exits between the electrodes. The
  current generated due to this potential
  difference relates to the rate of corrosion which
  is occurring on the more active of the electrode
  couple.
• Galvanic/Potential monitoring is applicable to
  the following electrode couples
• Bimetallic corrosion
• Crevice and pitting attack
• Corrosion assisted cracking
• Corrosion by highly oxidizing species
• Weld decay
• Galvanic current measurement has found its widest
  applications in water injection systems where
  dissolved oxygen concentrations are a primary
  concern. Oxygen leaking into such systems greatly
  increases galvanic currents and thus the
  corrosion rate of steel process components.
  Galvanic monitoring systems are used to provide
  an indication that oxygen may be invading
  injection waters through leaking gaskets or
  deaeration systems.

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Hydrogen Monitoring

• Hydrogen Monitoring provides an indaction that
  corrosion is taking or has taken place
• Plants or pipe lines that are exposed to wet sour
  gas (H2S) or acid conditions the generation of
  Hydrogen is a primary concern
• The concept of hydrogen probes is to detect the
  amount of hydrogen permeating through the steel
  by mechanical or electrochemical measurement and
  to use this as a qualitative indication of
  corrosion rate.

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Weight Loss Coupons

• The Weight Loss technique 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.
• The simplicity of the measurement offered by the
  corrosion coupon is such that the coupon
  technique forms the baseline method of
  measurement in many corrosion monitoring
  programs.

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Weight Loss Coupons

• The technique is extremely versatile, since
  weight loss coupons can be fabricated from any
  commercially available alloy.
• Localized corrosion can be identified and
  measured.
• Inhibitor performance can be easily assessed.
• Therefore, coupon monitoring is most useful in
  environments where corrosion rates do not
  significantly change over long time periods.
  However, they can provide a useful correlation
  with other techniques such as ER and LPR
  measurements.
•  

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Non-Destructive Testing Techniques (NDT)

• NDT instruments includes ultrasonic, radiography,
  thermograph, eddy curent measurement

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Analytical Techniques

• Analytical Techniques usually involves drawing
  off a fluid sample. This sample is sent to a
  laboratory for analysis
• The common analysis will look at Ph levels, iron
  and chlorides counts, oxygen and conductivity

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Pitting Factor Corrosion Rate
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Non Intrusive Sand Monitor
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Intrusive Sand Monitor
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MITIGATION OF MICWater Treatment

• Most Common Approach
• Preventative and Remedial
• Flexibility
• Costs
• Personnel Safety
• Environmental Concerns

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BIoGEORGE PROBE