Designing an Internal Corrosion Program

1
Designing an Internal Corrosion Program

• NACE Eastern Area Conference
• Roy D. Fultineer Jr.

2
Introduction

• Plans and Procedures
• Training
• Know the system
• When do we get involved
• Understand Corrosion Mechanisms
• Identify the right monitoring locations
• Monitor and Trend data
• Possible Mitigation
• Follow-up

3
Plans and Procedures

• Internal Corrosion Plans
• Generic
• Potential Treats Acid Gases, Bacteria, Erosion,
  etc.
• Types of monitoring
• Gas samples
• Liquid samples
• Coupons
• Requirements for internal corrosion monitoring
• Parameters to monitor and trend

4
Plans and Procedures

• Internal Corrosion Plans
• Generic
• Basic Decision Criteria
• If indications are found, what is the next step.

5
Plans and Procedures

• Internal Corrosion Plans
• Specific
• Location of facility
• Specific location of monitoring locations
• Specific timing of monitoring
• Specific water control methods
• Pigging
• Drips
• Dehydration
• Schedule of these control methods
• What action has been taken?

6
Plans and Procedures

• Internal Corrosion Plans
• Specific
• What action is planned?
• How will action be evaluated?

7
Plans and Procedures

• Procedures
• Procedures go into specific action of how to
  conduct sampling and monitoring
• Important aspect of internal corrosion plan
• Procedures go hand-inhand with training

8
Training

• Properly trained personnel is critical to the
  success of any internal corrosion program
• In house training
• On the job training
• NACE and other professional organizations
• Collecting accurate data is critical
• The better the data, the better the decisions

9
When do we get involved

• Internal corrosion should be considered in the
  initial design phase of any project
• Things to consider
• Water content and water removal
• Elevation profile
• Inlets and outlets to the system
• Gas Quality
• Flow regimes

10
Know your system

• Operation Factors
• Direction of flow
• Flow rates
• Flow regime
• Pressures
• Product
• Upsets
• Elevation Profile

11
Elevation Profile
12
Understand Corrosion Mechanisms

• Causes
• Water
• CO2 Influenced
• H2S Influenced
• MIC
• O2
• Velocity/Flow Related

13
Understand Corrosion Mechanisms

• Water
• Necessary for internal corrosion
• Temperature
• Reaction rates double for every 10 degree Celsius
  rise
• pH
• Less then 5 can result in increased corrosion
• Carbonates
• Acts as a acid buffer

14
Understand Corrosion Mechanisms

• CO2 Corrosion
• Carbon Dioxide water Carbonic Acid
• Carbonic Acid iron iron carbonate hydrogen
• Carbon dioxide is in the gas
• Carbonic acid creates corrosion
• Generally mild corrosion except when with other
  corrodents

15
Understand Corrosion Mechanisms

• H2S Corrosion
• Hydrogen Sulfide iron water
• Iron Sulfide water hydrogen
• From sour gas operations or from SRBs (MIC)
• Corrosion pitting occurs where FeS forms on the
  metal surface and creates a local corrosion cell

16
Understand Corrosion Mechanisms

• MIC
• Acid Producers - APBs
• Sulfate Reducing Bacteria - SRBs
• Controlled with a clean system and
  bacteriacides/biocides

17
Understand Corrosion Mechanisms

• Oxygen
• Oxygen iron water Iron oxide water
• Oxygen creates an oxidizing effect and with
  other corrodents accelerated corrosion
• Oxygen concentration cells create corrosion due
  to oxygen depletion areas

18
Understand Corrosion Mechanisms

• Velocity/Flow related attacks
• High surface fluid or particle velocities
• Erosion
• High Energy with or without particles
• Removes metal
• Leaves smooth surface
• Erosion Corrosion
• Erosion removes protective film or scale
• Exposes metal surface to environment

19
Pick the right monitoring locations

• Representative of system
• Right location
• Know what your looking for and put monitoring
  devices in right location.
• Top of the line versus bottom of line corrosion
• Right device
• Pick the monitoring device that is designed for
  the application

20
Monitor and trend data

• Collect the data you need and compare it to all
  other data
• Be careful not to add to much weight to any one
  data set
• Determine if action is required

21
Possible Mitigation Methods

• Do nothing
• Sometimes the best answer is to continue to
  monitor and study
• More information will lead to better decisions
• More technical or sophisticated analysis may be
  appropriate
• Chemicals can actually make the situation worse

22
Possible Mitigation Methods

• Liquid removal
• Drip Blowing
• Drip should be monitored and blown on frequencies
  that ensure no free liquids
• Used to monitor for corrosion parameters
• Pigging
• Ran on frequencies that ensure no free liquids
• Thought should be given to the type of pigs used
• Speed of pigging can influence

23
Possible Mitigation Methods

• Dehydration
• Removal of water through dehydration can greatly
  reduces possibility of internal corrosion
• High initial cost and added OM cost
• Does not necessarily remove the need for chemical

24
Possible Mitigation Methods

• Control Inlet Product Quality
• Monitor product quality entering system
• Have control to shut in suppliers

25
Possible Mitigation Methods

• Chemical Treating
• Batch
• Slug
• Continuous
• Squeeze

26
Possible Mitigation Methods

• Design
• One of the most effective means of control
• Use of proper materials
• Size pipeline properly (oversized liquid
  hold-up)
• Modeling and/or flow regime will dictate location
  and/or need for drips, pigging, etc.
• Material selection can be key
• Steel is not always the best solution
• Example Fiberglass piping in acid gas
  environment

27
Follow-up (Did it Work?)

• Coupons
• Liquid Sampling
• Residuals Monitoring
• In Line Inspection (ILI)
• Gas Monitoring

28
Coupons

• Weight Loss
• Compare previous rates to new rates
• Compare pretreated versus post-treatment
• CID Copper Ion Displacement monitoring
  chemical distribution

29
Liquid Sampling

• Monitor effects on water chemistry
• pH (increasing or decreasing)
• Increase Scaling
• Decrease Corrosion
• Metals (increasing decreasing)
• Mn/Fe ratio
• Trending
• Bacteria levels

30
Residual Monitoring

• Are chemicals getting where you need them
• Are the residuals adequate
• If not,
• Adjust existing facilities
• Add new injection points
• Change application (continuous to pigging)

31
ILI Inspection

• Need base line
• Follow-ups
• Monitor corrosion growth
• Monitor for new corrosion.

32
Gas Monitoring

• Monitor Quality
• CO2
• H2S
• Water
• O2
• Monitor for changes

33
Questions?