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MDP Chip piles – Marko Harinen, Stora Enso PCC Montes del Plata Supervisory Training 2011

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  • MDP Chip piles Marko Harinen, Stora Enso PCCMontes del Plata Supervisory Training 2011

    Montes del Plata Supervisory Training 2011

  • Uruguay chip pile system80 000m380 000m3Chips to digesterFinesStones + metal

    Montes del Plata Supervisory Training 2011

  • Meaning of chip piles:

    Intermediate storage to enshure constant chip feed to digester in different wood feeding problemsWhat kind of buffer MDP chippiles offer?Reduction of variance in chip qualityWhat kind of variations can be reduced with MDP pile system?

    Circular pile Pros and cons+ Relatively low storing times in uruguay compared to nordic mills+ uniform circulation of the pile = no bad sectorsless pile based raw material variationLess work to clean pile area- Limited possibility to reduce raw material variation from wood feeding

    Montes del Plata Supervisory Training 2011

  • Basic calculations in chip pile arearotation time

    Montes del Plata Supervisory Training 2011

    Sheet1

    Base figuresunitsfactorscalculation formula

    Pulp mill pulp production4080Adt/dADprod

    Pulp mill pulp production3672Bdt/dAd to Bd 0.9BD_prod=ADprod*0.9

    Wood needed6928tcooking yield: 0.53wood_in_tons=Bdprod/cooking yield

    wood needed12597m3swood density:550kg/m3wood_in_m3s=wood_in_tons/wood_density

    Chips needed in37791m3lchips packing factor: 3 m3/m3wood_in m3l=wood_in_m3s * packing factor

    Chippile size80000m3l

    chippile diameter118meducated quess

    chippile height29mchip pile angle 45 degreducated quess

    filling degree70%

    chips in one pile56000m3l

    rotation time of chips in pile3.0dwith 2 piles

    angle speed of the reclaimer4.6 / h

    chips in 1 degree sector222m3l

    spread of chips from stacker57.3

    spread of chips from stacker12.5h= mixing affect

  • Mixing properties of a circular chip pilePile formationPile is formed with chip layersStacker rotation directionTime:00:00Time:01:00Time:02:00Layer 1Layer 2Layer3

    Montes del Plata Supervisory Training 2011

  • Mixing properties of a circular chip pilePile unloadingReclaimer is pealing / unloading several layers at same time = Is mixing the chipsTime:00:00Time:01:00Time:02:00Layer 1Layer 2Layer3Reclaimer rotation direction

    Montes del Plata Supervisory Training 2011

  • Raw material variation exampleMDP chip pile is mixing with 12h average at speed 3700 Adt/d- Pile is unable to reduce Longer then 12 hours raw material variations

    Montes del Plata Supervisory Training 2011

    Chart1

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    450625.3846153846

    450610.7692307692

    450596.1538461538

    450581.5384615385

    450566.9230769231

    450552.3076923077

    450537.6923076923

    450523.0769230769

    450508.4615384615

    450493.8461538462

    450479.2307692308

    450464.6153846154

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    640464.6153846154

    640479.2307692308

    640493.8461538462

    640508.4615384615

    640523.0769230769

    640537.6923076923

    640552.3076923077

    640566.9230769231

    640581.5384615385

    640596.1538461538

    640610.7692307692

    640625.3846153846

    640640

    640640

    640640

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    640640

    640640

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    Density to chip piles

    density in to cooking

    time in hours

    basic density of a chips

    Chip pile affect to basic density to mill example(12 hour moving average) (Time shift between stacker and reclaimer removed)

    Calculation

    Base figuresunitsfactorscalculation formula

    Pulp mill pulp production3700Adt/dADprod

    Pulp mill pulp production3330Bdt/dAd to Bd 0.9BD_prod=ADprod*0.9

    Wood needed6283tcooking yield: 0.53wood_in_tons=Bdprod/cooking yield

    wood needed11424m3swood density:550kg/m3wood_in_m3s=wood_in_tons/wood_density

    Chips needed in34271m3lchips packing factor: 3 m3/m3wood_in m3l=wood_in_tons / packing factor

    Chippile size80000m3l

    chippile diameter118meducated quess

    chippile height29mchip pile angle 45 degreducated quess

    filling degree70%

    chips in one pile56000m3l

    rotation time of chips in pile3.3dwith 2 piles

    angle speed of the unloader4.6 / h

    chips in 1 degree sector222m3l

    spread of chips57.3

    spread of chips in time12.5h= mixing affect

    density example

    into chip pileinto digester

    0640

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    18640640

    19640640

    20640640

    21640640

    22640640

    23640640

    24640640

    0450625.3846153846

    1450610.7692307692

    2450596.1538461538

    3450581.5384615385

    4450566.9230769231

    5450552.3076923077

    6450537.692307692386.1538461538

    7450523.076923076943.75

    8450508.4615384615814.2857142857

    9450493.8461538462460

    10450479.2307692308

    11450464.6153846154

    12450450

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    24450450

    0640464.6153846154

    1640479.2307692308

    2640493.8461538462

    3640508.4615384615

    4640523.0769230769

    5640537.6923076923

    6640552.3076923077

    7640566.9230769231

    8640581.5384615385

    9640596.1538461538

    10640610.7692307692

    11640625.3846153846

    12640640

    13640640

    14640640

    15640640

    16640640

    17640640

    18640640

    19640640

    20640640

    21640640

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    density example

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    Density to chip piles

    density in to cooking

    time in hours

    basic density of a chips

    Chip pile affect to basic density to mill example(12 hour moving average)

    Sheet3

  • Screening Screening pros and cons based on Varkaus debarking plant?- - Result is sensitive to production changes

    Montes del Plata Supervisory Training 2011

  • Calculation exercise of chip characteristicsTask1: Estimate samples 1 & 2 basic and loose density kg/m3s and kg/m3l

    Use following constants:Volume of chips samples 1 & 2: 1.8 litre1m3s = 3 m3lDrycontent can be held as = 1 (dryied chips)

    Calculation:

    Montes del Plata Supervisory Training 2011

  • Calculation exercise of chip characteristicsTask2: Estimate samples 1 & 2 Dry content-%

    Use following constants:Volume of chips samples 3 & 4: 2.1 litre1m3s = 3 m3lBasic density of chips = 400kg/m3

    Calculation:

    Montes del Plata Supervisory Training 2011