Your SlideShare is downloading. ×
Matt Duxbury, Asia Iron Australia Extension Hill Magnetite Project - Case Study: Corrosion Mitigation Alternatives for Slurry Pipelines
Upcoming SlideShare
Loading in...5
×

Thanks for flagging this SlideShare!

Oops! An error has occurred.

×
Saving this for later? Get the SlideShare app to save on your phone or tablet. Read anywhere, anytime – even offline.
Text the download link to your phone
Standard text messaging rates apply

Matt Duxbury, Asia Iron Australia Extension Hill Magnetite Project - Case Study: Corrosion Mitigation Alternatives for Slurry Pipelines

931
views

Published on

Matt Duxbury, Manager- Infrastructure Services, Asia Iron Australia Extension Hill Magnetite Project presented this at the 3rd Annual Slurry Pipeline Conference. The Conference focuses on the design, …

Matt Duxbury, Manager- Infrastructure Services, Asia Iron Australia Extension Hill Magnetite Project presented this at the 3rd Annual Slurry Pipeline Conference. The Conference focuses on the design, construction, operation and maintenance of mineral slurry pipelines.

For more information, visit http://www.informa.com.au/slurrypipelineconference

Published in: Business, Technology

0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total Views
931
On Slideshare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
Downloads
29
Comments
0
Likes
0
Embeds 0
No embeds

Report content
Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
No notes for slide

Transcript

  • 1. Corrosion Mitigation Alternatives for Slurry Pipelines 3rd annual Slurry Pipeline Conference 13-14 November, 2013 * Duxton Hotel, Perth Asia Iron Australia Pty Ltd Matt Duxbury - Manager Infrastructure Services
  • 2. Disclaimer This Document is Confidential and may not be reproduced, redistributed or passed on, directly or indirectly, to any other person, or published, in whole or in part, for any purpose without prior written approval from Asia Iron Australia Pty Ltd and its subsidiaries (“AIA”). AIA makes no representations or warranty (express or implied) as to the accuracy, reliability or completeness of this document. AIA and its respective directors, employees, agents and consultants shall have no liability (including liability to any person by reason of negligence or negligent misstatement) for any statements, opinions, information or matters (expressed or implied) arising out of, or contained in or derived from, or for any omissions from this document, except liability under statute that cannot be excluded. This document contains reference to certain forecasts, projections, intentions, expectations and plans of AIA, which may or may not be achieved. They are based on certain assumptions which may not be met or on which views may differ. The performance and operations of AIA may be influenced by a number of factors, uncertainties and contingencies many of which are outside the control of AIA and its directors. No representation or warranty (expressed or implied) is made by AIA or any of its respective directors, officers, employees, advisers or agents that any forecasts, projections, intentions, expectations or plans set out in this document will be achieved, either totally or partially, or that any particular rate of return will be achieved. This Document is not a Prospectus nor an Offer to Subscribe for Shares.
  • 3. Presentation Outline 1.Extension Hill Magnetite Project 2.Historical approach to assessing corrosion mitigation 3. EHPL’s approach 4. What did we find? 4. What are we doing now 6.Concluding remarks
  • 4. Asia Iron Group Ownership Structure • 60% Chongqing SoE • 40% Private PRC • SoE involvement completed October 2010
  • 5. Extension Hill Project 280 km from Geraldton 6 – 8 Bt of ore
  • 6. Slurry Pipeline - Proven technology 2,000 Elevation in meters Da Hong Shan – 4MTpa Samarco – 13MTpa Extension Hill -10MTpa Length in km 400 6
  • 7. Slurry Pipelines Summit, Perth, 28 & 29 November 2011 In conclusion I Say To the slurry pipeline industry 1. More work is needed on understanding the chemistry • It is not reassuring to be advised that testing shows this or that is indeterminate, variable, uncertain etc… • There should be scientific explanations, mechanisms, 2. More co-operation and reporting of operations is needed. Extensive literature searches revealed a dearth of papers. 3. The pipeline owners, designers and corrosion specialists need to get together and bring the two areas together to bear on the problem Finally for Extension Hill 1. For EHPL the jury is still out! We have to decide by Feb/March 2012. 2. Is it chemical treatment, HDPE liner, epoxy liner, combinations, other, all are on the table? 7
  • 8. EHPL Pipeline Parameters Slurry System. • 288km, 20”, design point 10MTpa • Minimum design velocity 1.5m/s • Single pump station, inlet pressure 230bar • 67% CW design point Water pipelines, Return and Borefield • Return water line 20” 1,000 m3/hr flush , 650 m3/hr normal operations • Single pump station • Borefield, 37 km to mid point of return water line. 650 m3/hr injected at the mid point of the return water line, 20” to mid line, 22’ mid line to mine.
  • 9. Context EHPL Project • • • • • • Slurry pipes are industrial “dirty water” pipelines WA ground water is generally corrosive to bare steel EHPL water is 500ppm Cl-, 1,200 TDS, Traditional approach is ph control or use a liner Liner for EHPL is a $150m decision Oil&gas use production gas, vacuum de-aeration, and Nitrogen to deoxygenate large quantities of sea water, 2,500m3/hr, to <20ppb, finished with oxygen scavengers where needed, • Gold industry micro bubble Oxygen into cyanide slurry mix to increase oxygen in solution • Looking to combine this experience, and • Looking at the oxygen scavenging capacity of magnetite
  • 10. Comment on Oxygen & Chlorides • I’ve seen more than one case of using a nitrogen blanket to control Oxygen ingress in test rigs • All use ppm oxygen sensors • Corrosion of iron in an aqueous solution is supported down to about 20ppb • Chlorides act to depassivate in ph controlled pipelines, which promotes pitting at depassivated sites • General corrosion too high without passivation • ph control is compromised by high chlorides causing pitting, • Finally it doesn’t take much to set up pitting sites which persist under protective scales, • So recommendation under these circumstances is LINE IT!!!
  • 11. Context – Industry Corrosion Testing • Test rigs use ER and LPR probes and measure O2 ppm • Samples of actual materials and water in the presence of proposed pipeline coupon and record corrosion rates. • Tests run with various chemical treatments, • Results often variable and not definitive. Two sets of tests, 2005 and 2008, both indicated uncertainty, • No one could explanation the results in terms of the main chemical reactions at play, so how can chemical treatment be reliably? And over the length and life of the pipeline • Operation are poorly executed and experience poorly recorded and shared with other users • The chemistry over the length and life of a pipeline is very complex
  • 12. Corrosion Test Rig
  • 13. Nitrogen Blanket Removing Oxygen – Passing Nitrogen Blanket pbb 9ppm ppm ppb ppm 50ppb g
  • 14. Nitrogen removing oxygen static Nitrogen blanket
  • 15. The actual water, and pipe’s impact on dissolved oxygen ppm 10ppm Same period. looks like zero on the ppm scale ppb 20ppb Return water pipeline • Steel coupon only • Relatively large surface area • Sub 20ppb in 12 hours • 65km of the pipeline
  • 16. Slurry pipe steel coupon plus concentrate Same period. looks like zero on the ppm scale Sub 20ppb in 11 hours 40 minutes 12ppb
  • 17. Comment on Oxygen Chlorides • It is not uncommon to used a nitrogen blanket to control Oxygen in corrosion test rigs • All use ppm oxygen sensors • Corrosion in an aqueous solution is supported down to about 20ppb • Chlorides act to depassivate in ph controlled pipelines, which promotes pitting at depassivated sites • With general corrosion too high without passivation and with high chlorides causing pitting with ph controlled pipelines – recommendation is LINE IT!!!
  • 18. Two Test results for Magnetite Concentrate • Magnetite reduces ph enough to allow recommencement of corrosion over the time scale of EHPL’s slurry transport, i.e. 50 hrs, Lime addition to ph 10.5 ph hours Start 10.5 0 Mid 10.06 25 End 8.53 50 • ph did not decrease as much with increased Chloride level – unexplained • A possible mechanism is that Fe hydroxides form, and the resulting H+ neutralises ph
  • 19. Magnetite as an Oxygen Scavenger • EHPL’s magnetite is a weak oxygen scavenger, reducing native level of 9ppm to about 4ppm over the 50 hours of the tests, • Out next set of tests will include elevated temperature and retention time. Product comes out of the grinding process at 50-60DegC • Reaction rate doubles for every 10DegC increase, (tests were done at 25DegC) • Oxygen is the key - no oxygen no corrosion!
  • 20. Some Traps! • Soduim sulphide begins to disassociate at 6bar and is completely disassociated by 9bar. It takes about 30minutes to complete its work in the 15 -25deg C range? And yet I know it is used in slurry pipelines at these pressures. • Testing cannot replicate the entire length of a pipeline conditions, and our 50hour test is a very poor attempt to replicate conditions over the length of the pipeline • Let me make some observations for future testing
  • 21. Developing New Understandings • We have been working with Professor Rolf Gubner, the Chevron Chair of The Corrosion Centre at Curtin to plan the next set of tests • We need to get back to basic chemistry so that the principle chemical reactions are understood • We need to think about the length of the pipelines and the changing set of parameters over the length and over time, • For unlined pipes we need to set up a rigorous corrosion control processes, starting from hydro testing to project life’s end, and the best way to progress is, • That we need to use real conditions to develop our understanding and operating pipelines are the only real source of data for this analysis!
  • 22. Thank you Questions