Ninety Nine Diseases of Pressure Equipment in the Hydrocarbon Process Industry National Pressure Equipment Conference Banff, Alberta 10 February, 2005

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Ninety Nine Diseases of Pressure Equipment in
the Hydrocarbon Process IndustryNational
Pressure Equipment ConferenceBanff, Alberta 10
February, 2005

• John Reynolds
• Shell Global Solutions, US
• Houston, Texas

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What will I talk about this morning?

• Whats in the title (why the 99 Diseases)?
• Who should know about the 99 Diseases?
• How to use the 99 diseases to prepare RBI plans
• Establishing Integrity Operating Windows (IOWs)
  to avoid the 99 Diseases
• Where to learn more about the 99 Diseases?
• Then well cover a few of the 99 Diseases

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What are the 99 Diseases?

• General types of degradation mechanisms that can
  cause failure of pressure equipment, like
• General and localized corrosion and erosion
• Environmentally caused cracking
• Metallurgical aging and degradation
• High temperature degradation and brittle fracture
• Mechanical cracking and damage
• Welding and fabrication flaws
• Anything that will cause materials of
  construction to degrade and possibly cause
  failure of pressure equipment in service

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Who should know about the Diseases?

• Not just materials and corrosion specialists, but
  also
• Inspectors
• Operators
• Process and technology engineers
• RBI teams and PHA teams
• Project and equipment engineers
• Maintenance personnel
• Everyone that has a stake or role in preventing
  pressure equipment failures

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What do others need to know?

• Enough to help them recognize degradation issues
  and to seek help from materials and corrosion
  specialists, when necessary
• Enough to help them understand the importance of
  operating within the integrity operating windows
  (IOWs)
• Enough to help them understand and assess when
  changes to equipment and/or process conditions
  might cause changes in types of degradation or
  changes in rates of degradation

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Why Spread the Knowledge?

• Because in many cases of equipment failure, the
  materials and corrosion engineer is the one
  person that knew what could happen and could
  have helped to prevent the incident but was not
  in a position to do anything about it when it
  occurred
• Because the people on the front lines or the
  people making changes sometimes do not know about
  the types of degradation that might happen and
  what their role is in preventing pressure
  equipment failures

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Why call them the 99 Diseases?

• Theres a good analogy with the medical
  profession
• Its much easier, much less expensive, and
  healthier (safer) to prevent diseases than it is
  to cure them
• We would all rather know and practice the
  necessary lifestyles that will prevent us from
  having lung cancer or heart disease than it is to
  cure either after we contract them
• Same is true with the 99 diseases of pressure
  equipment
• Preventing cracks, high corrosion rates, and
  metallurgical degradation is usually easier, much
  less expensive, and safer than coping with the
  aftermath of unexpected vessel and piping
  failures.

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Automobile Analogy

• With good care, automobiles can operate
  dependably for well over 200,000 miles
• But it takes knowledge of what can go wrong and
  then doing the necessary preventive maintenance
  (ie, taking good care of our automobiles)
• Same is true for pressure vessels, heat
  exchangers, tanks, and piping
• If we take care of them, understand what can make
  them break down (ie, fail unexpectedly), and
  drive them with care (ie, operate them within
  the properly designated integrity operating
  window (IOW), they will provide reliable, safe
  service throughout the life of our process plants

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The 99 Diseases as input for RBI

• The 99 Diseases can be used as a checklist of
  possible causes of failure from which we glean
  the probable causes of degradation and failure
• Identifying all the possible degradation
  mechanisms is a critical success factor for RBI
• RBI team members each need to know a minimum
  amount about each possible/probable degradation
  mechanism in order to contribute effectively
• But only one RBI team member needs to be a
  materials and corrosion specialist

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Where can you learn more?

• Hundreds of materials and corrosion references
  that are available, but a new one really stands
  out
• API RP 571, Damage Mechanisms Affecting Fixed
  Equipment in the Refining Industry its written
  for the non-materials/corrosion specialist
• Or for other industries WRC 488 - Damage
  Mechanisms Affecting Fixed Equipment In Fossil
  Electric Power Industry and WRC 489 - Damage
  Mechanisms Affecting Fixed Equipment In The Pulp
  And Paper Industry
• Follow the whole series of the 99 Diseases in the
  Inspectioneering Journal, starting with the
  Jan/Feb 2003 edition

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Organization of Each Section in API 571

• Description of each damage mechanism
• Construction materials affected
• Critical factors that cause the damage
• Affected equipment and process units
• Description of the appearance of the damage
• Prevention and mitigation
• Inspection and monitoring
• Related damage mechanisms
• Other references on each type of damage mechanism
• Photos (macroscopic and microscopic)
• Very concise all this condensed into just 2-4
  pages for each damage mechanism

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Lets Cover a Few of the 99 Diseases

• Caustic Cracking
• Vibration Fatigue
• 885 Embrittlement
• Short-Term Overheating (Stress Rupture)
• Liquid Metal Cracking (LMC)
• Repair Welds
• External Chloride Stress Corrosion Cracking
• Naphthenic Acid Corrosion (NAC)
• Inadequate Overlay Weld Thickness/Chemistry

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Caustic Cracking

• One of the most common and best understood types
  of environmental cracking often results in
  white crystalline external deposits near leaks
• Cracks often wide-open, easy to see, but can be
  fine/tight
• Typically in non-PWHT weldments and other areas
  of high residual stresses
• Some common causes
• steaming out and carry-over into non-PWHT
  equipment
• Inadequately designed caustic injection nozzles
• Inadequate PWHT and non-PWHT repair welds
• Heat tracing in direct contact with caustic
  containing equipment
• Operators and maintenance people that dont
  understand the issue
• Would your RBI team know about all the potential
  sources of caustic that might crack your
  equipment in service?

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Vibration Fatigue

• Can lead to catastrophic consequences when
  vibrating nozzles fall off equipment or full bore
  piping separation occurs
• Often associated with SBP and screwed connections
• Usually associated with proximity to rotating
  machinery, but can also be associated with flow
  induced vibrations
• Inspection is not typically useful for avoidance
• Design modifications are key to corrective action
• Dont let vibration become the accepted norm at
  your plant!
• Do your operators know enough about the
  consequences of vibration fatigue such that they
  would report equipment vibration for possible
  mitigation?

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885 Embrittlement

• One of many types of embrittlement phenomena that
  can lead to brittle fracture of equipment in
  service
• Most commonly affects 400 series stainless steels
  in temperature range of 600-1000 F (highest
  embrittlement occurs at 885 F)
• Susceptible alloys suffer from toughness
  deterioration due to metallurgical changes in
  service
• Only detectable through some form of physical or
  mechanical testing (not NDE or inspection)
• Do you know about all the potential factors and
  conditions that might lead to embrittlement of
  your equipment in service?

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Short Term Overheating

• Also known as stress rupture not uncommon
  form of deterioration sometimes leads to
  catastrophic rupture
• Involves localized exposure to higher than design
  temperature at design operating pressures
  sometimes just a few degrees can substantially
  shorten service life
• Some susceptible equipment furnace tubes
  refractory lined equipment exothermic reactors
• Canadian HPU furnace hot spot rupture resulted in
  explosion gt fire gt fatality
• Preventable with IOWs, hot spot monitoring, IR
  scanning, heat sensitive paint, burner
  management, temperature monitoring, etc.
• Do your operators have all the tools and
  knowledge to avoid short-term overheating
  failures?

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Liquid Metal Cracking (LMC)

• A very insidious and very rapid cracking
  mechanism
• Also known as Liquid Metal Embrittlement (LME)
• Affects numerous alloys of Al, Cu, Ni, and Fe
  (SS)
• Aluminum core exchangers have failed due to
  Mercury LMC two incidents with huge
  consequences
• Galvanized coating (Zn) melts at 780F and drips
  on SS equipment causing LMC
• Cadmium plating on bolts melts at 480F --gt LMC
• Do you know if some of your equipment may be
  susceptible to LMC?

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Repair Welds

• Another potentially undetected flaw, sometimes
  with fairly insidious consequences
• Repair welds are not infrequently the initiation
  site for cracking or corrosion failures
• Often repair welds (both shop and field) dont
  get reported or recorded and can have inadequate
  QA/QC
• Some construction codes dont treat repair welds
  adequately in terms of specified QA/QC
• Repair welds can produce metallurgical notches,
  stress raisers, high hardness, and dissimilar
  weld issues
• Do you require your fabricators and maintenance
  forces to record and report all repair welds for
  your records?

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External Chloride Stress Corrosion Cracking

• ECSCC is an off-shoot of effective CUI programs
  and is difficult to avoid and inspect for
• Affects insulated solid SS equipment in CUI range
  from 140F (60C) to 300F (150C), and higher temps
• Even good CUI coatings break down after 10-15
  years allowing moisture and chlorides to contact
  the external surfaces under insulation
• Chlorides come from insulation and the atmosphere
• Fortunately SS toughness usually leads to LBB
• Do you have insulated solid SS equipment that may
  be susceptible to ECSCC?

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Naphthenic Acid Corrosion (NAC)

• An old problem that we are continuing to learn
  more about
• Higher severity operations sometimes lead to more
  NAC in places where we did not find it before
• TAN, organic acids, sulfur content, temperature,
  and velocity all combine to determine extent of
  NAC
• Usually results in highly localized corrosion,
  but can be general thinning in lower alloys
• Prevention includes upgrading to higher Moly
  containing alloys or blending crude diets
• NAC susceptibility can be predicted with the
  CORAS model
• Would your MOC program be able to predict
  accelerated NAC problems from changes in crude
  diets?

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Weld Overlay Thickness/Chemistry

• Steel vessels, exchangers, flanges commonly weld
  overlaid with high alloy for corrosion resistance
• Its vital that the top surface of the overlay be
  the right alloy content to resist process
  corrosion, especially if there will be final
  grinding or machining
• The proper thickness and chemistry QA/QC should
  be specified following multiple layers of weld
  overlay
• Dont count on the machinist or grinder to know
  that he is defeating your corrosion allowance!
• Have you ever seen localized corrosion or rust
  stains bleeding through a weld overlaid surface?

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Some More of the 99 Diseases

• Graphitization - Temper Embrittlement Strain
  Aging Soil Corrosion Atmospheric Corrosion-
  CUI Reheat Cracking Dealloying Condensate
  Corrosion Oxidation Sulfidation MIC CO2
  Corrosion Cavitation Thermal Shock
  Carburization Hydrogen Embrittlement Sour
  Water Corrosion Ti Hydriding HTHA HCl
  Corrosion Overhead Corrosion Dew Point
  Corrosion Delayed Hydrogen Cracking ECSCC
  NAC HIC SOHIC PASCC Metal Dusting Fuel
  Ash Corrosion Corrosion Fatigue Chloride
  Cracking Nitriding Brittle Fracture
  Cavitation Thermal Fatigue Steam Blanketing
  Erosion Refractory Failure Cooling Water
  Corrosion Graphitic Corrosion DMW Cracking
  Sigma Phase Embrittlement Mechanical Fatigue
  Spheroidization Erosion-Corrosion Galvanic
  Corrosion Carbonate Cracking Green Rot

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Questions to Ponder

• Do all the right people at your operating plant
  know enough about the 99 Diseases in order to do
  their part in preventing pressure equipment
  failures?
• Do you have integrity operating windows (IOWs)
  established for all the 99 Diseases to which you
  may be susceptible?
• Do your RBI plans consider all the 99 Diseases
  when considering the risk of failure at your
  plant?

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Ninety Nine Diseases of Pressure Equipment in the
Hydrocarbon Process IndustryTime for Questions?

• John.reynolds_at_shell.com
• Houston, Texas