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-in–hand 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 SRB’s (MIC) • Corrosion pitting occurs where FeS forms on the metal surface and creates a local corrosion cell

16. Understand Corrosion Mechanisms • MIC • Acid Producers - APB’s • Sulfate Reducing Bacteria - SRB’s • 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 O&M 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?