engro fertilizers - muhammad azhar mailk.pdf

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  • Incorrect Steam Drum

    Level Measurement Can

    Result In Multiple

    Issues At Ammonia

    Plant Muhammad Azhar Malik

    Feb 26, 2015

  • Presentation Synopsis

    Purpose of Paper

    Process Description

    Problems Encountered

    Root Cause Analysis

    Conclusion

    26 February 2015 2

  • Purpose of Paper

    Sharing Engro's experience on issues faced on HTSC catalyst early

    deactivation, waste heat boiler fouling, turbines fouling post new

    fertilizer plant successful startup mainly due to incorrect Steam drum

    level measurement.

    Root cause analysis of problems encountered

    Remedial measures taken to overcome problems.

    26 February 2015 3

  • 26 February 2015 4

    Worlds Largest single-train Ammonia-Urea complex at the time of

    commissioning.

    Successfully Commissioned in Dec 2010.

    Steam Header Network Configuration

    KS Steam 110 kg/cm2

    HS Steam 44 kg/cm2

    LHS Steam 41 kg/cm2

    LS Steam 3.5 kg/cm2

    Plant Introduction:

  • 5

    Steam Network Configuration:

    110 kg/cm2 Steam Drum

    42 kg/cm2 Aux

    Boiler

    Process Steam to Furnace

    Heat recovery from WHB Sec Ref / HTS / Amm Convertor

    KS Super heater

    Syntheses Turbine

    Refrig Turbine

    CO2 Comp Turbine

    PA Comp Turbine

    CW Turbine

    BFW Turbine

    PW Turbine

    ID fan Turbine

    Lube oil Turbine

    KS Network

    HS Network 44 kg/cm2

    LHS Network 41 kg/cm2

    LS Network 3.5 kg/cm2

  • Problems Encountered

    26 February 2015 6

  • HTS Catalyst Failure

    26 February 2015 7

    HTS Catalyst bed undergoes replacement just after two

    effective years of operation.

    Plant load got limited due to high delta pressure across HTS

    bed - 1.8 kg/cm2

    The temperature profile across catalyst bed showed signs of

    channeling.

  • 26 February 2015 8

  • HTS Bed Radial Temperature profiling

    26 February 2015 9

    TI-2091

    TI-2092

    Window - 1

    Window - 2

    Window - 3

    Window - 4

    Window - 5

    Window - 6

    ACTIVE PORTION (~42% of circumference)

    DEAD PORTION (~58% of circumference)

    380C

    378C

    441C

    430C

    426C

    412C

    377C

    378C

  • 26 February 2015 10

    2ft catalyst bed shrinkage Channelling Signs in

    HTS bed

  • 26 February 2015 11

    Dust at Al balls at HTS Top Analysis showed

    7% Sodium & 1% Silica contents

  • HTS Failure - Root cause Analysis

    26 February 2015 12

    Inspection revealed Presence of

    Shrinkage of 2% catalyst bed with clear signs of channeling

    High contents of foreign particles especially Sodium & Aluminium

    Crushed catalyst due to increased delta pressure operation

    Presence of Sodium questioned steam quality

    Presence of Aluminium showed slippage from alumina lumps

    from Secondary reformer

  • WHB Fouling

    26 February 2015 13

    Temperature at WHB outlet increased by 25 C.

    Inspection showed fouling of WHB tubes

    Analysis of dust revealed presence of Sodium and Aluminum.

    A lot of dust was also collected at WHB cold end showing

    slippage from secondary reformer

  • 26 February 2015 14

    WHB Tube Fouling Dust Analysis Showed

    Sodium 8% and Aluminum 18%

  • BFW Turbine Fouling /Internal seals Failure

    26 February 2015 15

    BFW turbine TP-1301 A efficiency dropped significantly.

    BFW header pressure reduced by 4 kg/cm2.

    Upon inspection, interstage seals of the turbine was found

    damaged

    Rotor was found covered with heavy deposits.

    Analysis showed presence of 40% Sodium contents.

    Table 4: Deposit Analysis at TP-1301 A

    Componenet Analysis result

    Sodium 39.47%

    Silica 0.31%

    Potassium 1.63%

  • 26 February 2015 16

    Deposits of Sodium on Turbine Interstage seal

  • 26 February 2015 17

    Deposits of Sodium on interstage seals

  • ID fan Turbine Fouling

    26 February 2015 18

    ID fan Turbine vibrations increased till the danger level till 0.34

    um.

    Efficiency of turbine also dropped significantly

    Inspection showed presence of deposits sodium on the rotor

  • 26 February 2015 19

    Fouling of ID fan Turbine Rotor

  • Root Cause Analysis

    Prime reason of above mentioned problems was High quantity of

    sodium in Steam.

    Sources of Steam

    Steam Drum 110 kg/cm2 Heat recovery from WHB at ammonia

    Auxiliary Boiler 42 kg/cm2

    The reason for poor steam quality was incorrect steam drum

    level measurement and its control.

    26 February 2015 20

  • Steam Drum Level

    Level remained higher then normal causing poor steam quality.

    26 February 2015 21

    Marks of High

    level operation

    Normal Level

  • Remedial Measures

    Correction of Level Measurement

    Algorithm for level correction was corrected for correct level

    transmitter type.

    Steam Drum equipped with 02 new DP type transmitters in addition of

    03 float type meters

    Steam Drum equipped with Conductivity Meter

    Isolation Valves at Steam drum rectified.

    Maintenance regime for floats of level transmitter at every 6 month

    implemented.

    26 February 2015 22

  • Remedial Measure

    Wet Washing regime for Turbines was implemented.

    Make up water Quality improved

    RO unit and DMW beds were lined up in series

    Conductivity dropped to 0.2 us.

    DMW is then passed through Polisher to fed to Steam drum.

    Steam header Wet Washing

    Entire steam headers wet washing carried out

    26 February 2015 23

  • Conclusion

    By taking above mentioned steps, Steam quality improved

    significantly.

    26 February 2015 24

  • 26 February 2015 25

    Thank You !!!

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