INCREASING PLANT RELIABILITY & INTEGRITY MANAGEMENT USING CFD

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					         VP - SPEC Technologies Inc.




INCREASING PLANT RELIABILITY
  & INTEGRITY MANAGEMENT
   USING CFD & CORROSION
         SIMULATION


          Regan Pooran, P.Eng.
      VP-SPEC TECHNOLOGIES INC.
       TOPICS OF DISCUSSION

   Who VP-SPEC Technologies Inc. is?

   Key Purpose, Process & Payoff for our
    discussion

   Briefly review a real world case:
    Deterioration of an Amine System
    Regenerator

   Conclusion
                                            2
WHO ARE WE?




              3
        VP-SPEC TECHNOLOGIES INC
              BACKGROUND

•   We are a consulting company (based out of Oil Rich
    Alberta) specializing in Asset Management Systems –
    focusing mainly on the Process Industry.

•   Our customer base includes: Husky Energy, Suncor,
    Nalco/ Exxon, EnCana Energy, Enerplus Trust etc…




                                                     4
PURPOSE, PROCESS, PAYOFF




                       5
PURPOSE, PROCESS, PAYOFF
•   Key Purpose:
    •   To demonstrate how CFD (Fluent Inc., CFD Modeling ) & Corrosion
        Simulation (OLI Systems, Corrosion Analyzer) are applied
        synergistically to improve Plant Reliability & Integrity
        Management.

•   Process:
    •   Discuss how CFD & Corrosion Simulation were applied to confirm
        deterioration mechanisms in an Amine System Regenerator that
        has had multiple failures
    •   Open discussion – please interrupt if you have questions

•   Payoff:
    •   An understanding of how CFD & Corrosion Simulation can be
        applied to improve your Plant’s Reliability & Integrity Management
                                                                         6
     THE TRADITIONAL &
THE IMPROVED PERSPECTIVE
   FOR ASSET INTEGRITY
       MANAGEMENT



                       7
    TRADITIONAL PERSPECTIVE
•   Traditionally plants have entirely relied on results from
    internal inspections, corrosion monitoring with coupons and
    probes, thickness measurements, and process constituent
    monitoring to assess equipment integrity and prevent
    equipment failures.

•   These results, however, produce either coincidental or
    lagging indication of deterioration activity within equipment:

    -   Coincidental indicators (e.g. TM) provide information on
        deterioration activity at same time this activity is occurring.
        Lagging indicators (e.g. internal inspections) provides
        information on deterioration activity that trail behind this
        activity.

•   Further these results provide limited insights into the
                                                                          8
    deterioration mechanism
AN IMPROVED PERSPECTIVE
•   For systems that can incur significant economic and
    safety consequences, if failures happen, coincidental
    and lagging indications of deterioration activity are
    simply not sufficient.

•   In these systems, predictive indications and
    parameter sensitivity studies of deterioration activity
    is additionally required for optimum equipment
    reliability and integrity management.




                                                          9
REVIEW OF PROBLEMS WITHIN
     AN AMINE SYSTEM




                       10
             AMINE SYSTEMS
•   Amine systems remove H2S and CO2 from field gas or
    from effluent gas of various plant systems

•   Equipment failures in amine systems can produce
    significant economic and safety consequences for an
    owner-user.

    -   Thus, predicting deterioration activity and
        conducting sensitivity studies on high-risk
        equipment in these systems can be justified.




                                                       11
AMINE SYSTEM FLOW SCHEME




                      12
  REVIEWED SAMPLE CASE

• Specific real world sample case in review:
  Deterioration of an Amine Regenerator from
  Trays 20-15 (Upper Section)




                                               13
DETERIORATION OF REGENERATOR
         TRAYS 20-15
1. Deterioration history of Amine Regenerator from
   Trays 20-15 is described as such:

   •   Hole-through was experienced at Trays 20 & 15 level

   •   Deterioration progressed from Tray 20 to 15 over time

   •   Deterioration observed from inspection (in 2005):
       -   In between trays (specifically at or slightly above vapor/
           liquid interface level at each tray)
       -   On tray support in welded area
       -   In downcomer areas and circ seam

       •   Deterioration was most significant in downcomer
           areas and circ seams
                                                                   14
DETERIORATION OF REGENERATOR TRAYS 20-19
  SECTION (ILLUSTRATION – W/ DESCRIPTION)




                                      15
ACTUAL CAUSE ANALYSIS:
REGENERATOR DETERIORATION




                            16
   CS DETERIORATION RELATIONSHIP
(Erosion - Scale Removal - Corrosive Fluid)

                             Removes         Protective Iron Sulfide
 Mechanical Erosion
                                                      Scale

                                                          Exposes
           Micro-Machines
                                                          Carbon Steel
           Away
                                                          (CS) Metal To


                      Attacks & Corrodes
     CS Metal                                  Corrosive Solution




Total Deterioration CS Metal Loss = Erosion Rate + Corrosion Rate + Erosion-
Corrosion Interaction Synergy (≈50%)

                                                                       17
 REGENERATOR UPPER
SECTION DETERIORATION



                    18
BUILDING THE CASE FOR DETERIORATION
      & FAILURE IN REGENERATOR
   Discussion of following items will build case for
    identifying actual causes of deterioration & failures
    experienced at Trays 20 to 15 in Regenerator:

    – Temperature depression at Regenerator’s Overhead


    – Amine solution corrosiveness in Regenerator’s Upper
      Section

    – Droplet-impingement-erosion and particle-erosion of
      protective iron sulfide scale and CS metallurgy

                                                            19
                          DETERIORATION & FAILURE IN
                         REGENERATOR (Temp Fluctuation)
                                                                  Regenerator (53-C-201) OHD Temp (C)
                                                                L2Regenerator OHD Temp (C)
                      120.00
                                                                 101 C                                                                                   97 C                                                     103 C
                      115.00
    Temperature (C)




                      110.00
                      105.00
                      100.00
                       95.00
                       90.00
                       85.00
                       80.00
                               6-Jan-03




                                                     6-Jul-03

                                                                 6-Oct-03




                                                                                                  6-Jul-04

                                                                                                             6-Oct-04




                                                                                                                                              6-Jul-05

                                                                                                                                                           6-Oct-05




                                                                                                                                                                                            6-Jul-06

                                                                                                                                                                                                       6-Oct-06
                                                                            6-Jan-04




                                                                                                                        6-Jan-05




                                                                                                                                                                      6-Jan-06




                                                                                                                                                                                                                   6-Jan-07
                                          6-Apr-03




                                                                                       6-Apr-04




                                                                                                                                   6-Apr-05




                                                                                                                                                                                 6-Apr-06
                                                                                                                        Date


•   Regenerator OHD temp depressed mid-Oct 04 (maybe related to
    amine type conversion?) and increased mid-Oct 06 (maybe related to
    amine reclamation?)

•   Thus, temperature at Trays 20 to 15 possibly depressed for 1 year
                                                                     20
    prior to time deterioration was noted (2005 inspections)
                          DETERIORATION & FAILURE IN
                         REGENERATOR (Temp Fluctuation)
                                                                  Regenerator (53-C-201) OHD Temp (C)
                                                                L2Regenerator OHD Temp (C)
                      120.00
                                                                 101 C                                                                                   97 C                                                     103 C
                      115.00
    Temperature (C)




                      110.00
                      105.00
                      100.00
                       95.00
                       90.00
                       85.00
                       80.00
                               6-Jan-03




                                                     6-Jul-03

                                                                 6-Oct-03




                                                                                                             6-Oct-04
                                                                            6-Jan-04




                                                                                                  6-Jul-04




                                                                                                                        6-Jan-05




                                                                                                                                              6-Jul-05

                                                                                                                                                           6-Oct-05

                                                                                                                                                                      6-Jan-06




                                                                                                                                                                                            6-Jul-06

                                                                                                                                                                                                       6-Oct-06

                                                                                                                                                                                                                   6-Jan-07
                                          6-Apr-03




                                                                                       6-Apr-04




                                                                                                                                   6-Apr-05




                                                                                                                                                                                 6-Apr-06
                                                                                                                        Date


•   Temperature depression would increase H2S solubility and solid iron
    sulfide loadings in amine solution at Trays 20 to 15 level and make
    this solution more corrosive and erosive
•   There was no available data that could be credibly used as a proxy
    for H2S loading variability in amine solution at Trays 20 to 15 level21
DETERIORATION & FAILURE IN REGENERATOR
       (Solution Corrosiveness, T-15)
         CS CR w/ Scale at Regen (T-15) as a Function of H2S Conc & Temp




              Ref H2S (0.7 mol %)
                                           Ref Temp (121 C)




•   Carbon Steel CR (< 3 mpy, T-15) w/ scale present for up to 10X
    Ref H2S concentration (0.7 mole %) regardless of temp      22
DETERIORATION & FAILURE IN REGENERATOR
       (Solution Corrosiveness, T-15)
        CS CR w/o Scale at Regen (T-15) as a Function of H2S Conc & Temp




                                          Ref Temp (121 C)
             Ref H2S (0.7 mol %)
             Ref H2S (0.7 mol %)
                                          Ref Temp (121 C)




•   Carbon Steel CR (28 mpy, T-15) w/o scale present at 4X
                                                         C)
    Ref H2S concentration (0.7 mole %) & lower temp (11523
DETERIORATION & FAILURE IN REGENERATOR
       (Solution Corrosiveness, T-15)
        CS CR w/o Scale at Regen (T-15) as a Function of H2S Conc & Temp




                                          Ref Temp (121 C)
             Ref H2S (0.7 mol %)
             Ref H2S (0.7 mol %)
                                          Ref Temp (121 C)




•   Comprehensive review into mechanisms responsible for
    removing protective iron sulfide scale was thus required.
                                                         24
       DETERIORATION & FAILURE IN
      REGENERATOR (CFD Evaluation)
   CFD was executed:

    – to confirm if particle-erosion did contribute to
      deterioration of protective iron sulfide scale and erode CS
      metallurgy in downcomer areas

    – to confirm if droplet-impingement-erosion was a
      contributing factor in deterioration noted at vapor/ liquid
      interface between trays




                                                              25
           DETERIORATION & FAILURE IN
          REGENERATOR (CFD Evaluation)




Contours of velocity intensity at   Contours of particle-erosion rates
the downcomer walls                 at the downcomer walls (kg/m3.s)

                                                                 26
           DETERIORATION & FAILURE IN
          REGENERATOR (CFD Evaluation)

               Parameter                  Case 1   Case 2
    Solids (Iron Sulfide) Concentration
    wt.% in Rich Amine                    1.0 %    2.0 %

    CFD Max CS Erosion Rate Predictions
    (mpy)                                   13       25



•    Max erosion rate in downcomer areas nearly double (13
     → 25 mpy) with increased solids loading (1.0 → 2.0%)




                                                            27
    DETERIORATION & FAILURE IN REGENERATOR
       (Erosion-Corrosion Deterioration Rate)
     Tray    H2S %    Temp, C      CS CR            CS CR      Erosion   Synergy    Total1
                                (mpy – w/ scale)   (mpy - wo     Rate      (%)      Metal
                                                     scale)     (mpy)              Loss Rate
                                                                                    (mpy)
    20 (H)    3.7       105           2.2            35.2        13        50        72.3
    15 (M)    0.7       121           1.0            11.5       6.5        50         27
Note 1: Total Metal Loss (at reference values) = CS CR (wo/ scale) + ER + Synergy
Note 2: CS Erosion Rate (mpy) based on 1% solids


•    If protective scale is present, CR for CS low (< 3 mpy) for Trays
     20-15, and erosion is not applicable

•    If particle-erosion and droplet-impingement-erosion is a factor,
     protective scale is removed and there is erosion-corrosion
     synergy contribution to total metal loss

                                                                                        28
    DETERIORATION & FAILURE IN REGENERATOR
       (Erosion-Corrosion Deterioration Rate)
     Tray     H2S %   Temp, C      CS CR            CS CR      Erosion   Synergy    Total1
                                (mpy – w/ scale)   (mpy - wo     Rate      (%)      Metal
                                                     scale)     (mpy)              Loss Rate
                                                                                    (mpy)
    20 (H)      3.7    105            2.2            35.2        13        50        72.3
    15 (M)      0.7    121            1.0            11.5       6.5        50         27


•    Total metal loss rate (mpy) increases up Regenerator due to
     lower temperatures, increase H2S concentrations, and higher
     iron sulfide loadings as one proceeds up Regenerator:
     -      Lower temperatures enable more H2S to dissolve in liquid
     -      Higher H2S concentrations in liquid decrease pH and
            increases iron sulfide loadings
     -      The lower the pH of liquid, the more corrosive it is to
            exposed metal
     -      Higher the iron sulfide loadings, higher the erosion rate 29
CONCLUSION




             30
                 CONCLUSION
•   In conclusion: Predictive indication and parametric
    sensitivity studies (using CFD & Corrosion Simulation)
    enabled us to significantly improve equipment reliability &
    integrity management by:

    -   determining equipment deterioration sensitivity to key
        process parameters (i.e. H2S concentration increase,
        iron sulfide solids loading)

    -   predicting locations and magnitude of maximum metal
        loss

    -   proactively identifying operational parameter targets to
        minimize deterioration
                                                             31
Any Questions?




                 32

				
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