chip piles part m harinen

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


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


Basic calculations in chip pile arearotation time


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


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


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


Chart1

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450493.8461538462

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450464.6153846154

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640493.8461538462

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640537.6923076923

640552.3076923077

640566.9230769231

640581.5384615385

640596.1538461538

640610.7692307692

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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

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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

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2640493.8461538462

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4640523.0769230769

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6640552.3076923077

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8640581.5384615385

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10640610.7692307692

11640625.3846153846

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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


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:


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:


chip piles part m harinen

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