DEVELOPMENT OF WOOD-BASED PELLET PRODUCTION AND …

Matti Kuokkanen, University of Oulu, Department of Chemistry

ChemicalChemical methodsmethods in the in the developmentdevelopment of of ecoeco--efficientefficient pellet pellet productionproduction and and

utilizationutilization of of woodwood ashash

12.5.200912.5.2009


DEVELOPMENT OF WOODDEVELOPMENT OF WOOD--BASED PELLET BASED PELLET PRODUCTION AND TECHNOLOGYPRODUCTION AND TECHNOLOGY

MAIN FIELDS OF OUR PELLET RESEARCHMAIN FIELDS OF OUR PELLET RESEARCH

1. Developing new materials for pellet production1. Developing new materials for pellet production2. Effective harnessing of industrial secondary flows2. Effective harnessing of industrial secondary flows3. Binding material applications3. Binding material applications4. Biodegradation of pellets and materials used; BOD 4. Biodegradation of pellets and materials used; BOD OxiTopOxiTop5. Cross5. Cross--linking mechanisms of woodlinking mechanisms of wood--based pellets; optical based pellets; optical

microscopic staining methodmicroscopic staining method6. Drying processes of pellet raw materials, also new technologi6. Drying processes of pellet raw materials, also new technologieses7. Properties of wood ash in terms of its eco7. Properties of wood ash in terms of its eco--efficient utilizationefficient utilization

University of Oulu, Department of Chemistry / Department of Process and Environmental Engineering

M.Sc.(Tech.) Matti Kuokkanen

matti.kuokkanen @oulu.fi

mailto:[email protected]

mailto:[email protected]


PelletizingPelletizing –– BackgroundBackground

PatentedPatented 1976 (USA), 1976 (USA), afterafter oiloil crisiscrisis

SwedenSweden as as pioneerpioneer countrycountry

UseUse overover 1M tn/1M tn/yearyear, , smallsmall scalescale useuse commoncommon

UseUse of of pelletspellets becamebecame common common onlyonly just in 21st just in 21st centurycentury, , reasonsreasons::

IncreaseIncrease in in oiloil priceprice and and oiloil reservereserve exhaustionexhaustion

ClimateClimate politicalpolitical reasonsreasons

Emission Emission tradetrade in EU, in EU, pelletspellets COCO 22 neutralneutral

IncreaseIncrease of of profitabilityprofitability for for alternativealternative energyenergy formsforms


PelletizingPelletizing -- BackgroundBackground

EuropeEurope::

DEN DEN significantsignificant useruser

RUS RUS secondsecond largestlargest producerproducer ((caca. 650 000 tn/. 650 000 tn/yearyear --05)05)

AUT AUT expansionexpansion in in useuse, , especiallyespeciallyin in oneone--familyfamily houseshouses

BalticBaltic CountriesCountries significantsignificantexportersexporters alongalong withwith FINFIN



USA and USA and CanadaCanada::

Pellet Pellet fireplacefireplace becamebecame common in midcommon in mid--1980s1980s

MainlyMainly usedused in in oneone--familyfamily househouse and and vacationvacation home home heatingheating

OverOver millionmillion pellet pellet fireplacesfireplaces



TrendTrend of pellet of pellet productionproduction capacitycapacity in Finland:in Finland:

19981998 10000 10000 tonnestonnes

20012001 80000 80000 tonnestonnes

2003 170000 2003 170000 tonnestonnes

2005 400000 2005 400000 tonnestonnes

2009 2009 estimatedestimated 1M 1M tonnestonnes

RapidRapid growthgrowth

ProductionProduction capacitycapacity limitlimit hashas alreadyalready beenbeen reachedreached withwith traditionaltraditional rawraw materialsmaterials ((shavingsshavings and and drydry cuttercutter chips)chips)

AimAim to to expandexpand rawraw materialmaterial basisbasis

In Finland In Finland caca. 15. 15--20M tn/20M tn/yearyear biomassbiomass is is leftleft unusedunused in in forestsforests duringduring forestryforestry operationsoperations

UtilizationUtilization of new of new rawraw materialsmaterials ((barkbark, , thinningthinning and and logginglogging residuesresidues, , branchesbranches, , stocksstocks, , ””trashtrash treetree speciesspecies””))



Pellet Pellet productionproduction hashas beenbeen undevelopedundeveloped

NeedNeed for for researchresearch and and developmentdevelopment workwork in pellet in pellet productionproduction and and technologytechnology

IncreasedIncreased informationinformation for for consumersconsumers

AlongAlong withwith pelletspellets alsoalso pellet knowpellet know--how how willwill bebe exportexport productproduct



RawRaw materialmaterial is is pressedpressed throughthrough matrixmatrix

FrictionFriction increaseincrease

TemperatureTemperature increaseincrease

PressurePressure increaseincrease

LigninLignin solidificationsolidification duringduring coolingcooling periodperiod

FormingForming of compact of compact structurestructure




ProblemsProblems of pellet of pellet productionproduction

1. 1. DustDust problemproblem

ExposureExposure healthhealth riskrisk

http://http://www.tyoturva.fiwww.tyoturva.fi/toimialat/puuteollisuus//toimialat/puuteollisuus/puupoly.htmlpuupoly.html

OccupationalOccupational safetysafety instructionsinstructions mustmust bebe observedobserved in in pellet pellet plantsplants

DangerDanger of of explosionexplosion and and firefire in in combustioncombustion

SievingSieving of of disadvantageousdisadvantageous particleparticle sizesize

UseUse of of bindingbinding materialsmaterials

http://www.tyoturva.fi/toimialat/puuteollisuus/puupoly.html






2. 2. QualityQuality and and compactnesscompactness

LogisticLogistic problemsproblems –– itit is is notnot profitableprofitable to transport to transport finesfines

ImportantImportant for for smallsmall scalescale usersusers

IncreaseIncrease of of domesticdomestic consumptionconsumption in Finlandin Finland

Small Small scalescale burnersburners areare sensitivesensitive for for qualityquality changeschanges

CanCan bebe affectedaffected withwith bindingbinding materialsmaterials and and pretreatmentpretreatment techniquestechniques


ProblemsProblems of pellet of pellet productionproductionAsh and slagging problem in combustion

Pulpwood Undelimbed mixed wood



3. 3. UnderdevelopmentUnderdevelopment of of equipmentequipment

EnergyEnergy efficiencyefficiency

BAT BAT mustmust bebe introducedintroduced

ResearchResearch and and developmentdevelopment workwork as as solutionsolution

Pellet Pellet researchresearch methodsmethods

Measurement Equipment Purpose of determinationMoisture content Heat oven and scales Amount of water content

Density Volume and weight determinations Compactness of materials

Calorific heat Bomb calorimeter Energy content

BOD tests BOD Oxitop® equipments Biodegradation / loss of materials

Dust content, strength properties

Vibrator, sieve analysis Mechanical stability of the pellet

Structure analysis Staining reagents and optical microscope

Information about pellet structure and cross-linking mechanism

TG analysis Thermogravimeter Volatilization of water and VOC`s, ash content

Elementary analysis ICP/OES Heavy metals and/or nutrients

Particle size distribution Laser diffraction particle size analyzer, image analysis

Information about particle size distribution in wood materials


Table 1. Useful research methods for pellet production and development.

BOD measurements

BOD OxiTop system used for biodegradability studies in solid (left) and liquid (right) phase

BOD measurements

Biodegradation of pellets

Biodegradation of raw materials and binding agents

-> Information of material loss-> Information of storage and transport effect-> Information of binding agent effect for pellet biodegradation

Biodegradation of pellets with different binding materials within 28 days

0

0,05

0,1

0,15

0,2

0,25

0,3

0 10 20

Time [d]

BO

D/T

hOD

[%]

Potato peel residue

Lignosulphonate

No binding materialsused


MicroscopicMicroscopic stainingstaining methodmethod1. 1. EpoxyEpoxy moldingmolding of pellet of pellet samplessamples

-- TwoTwo orientationsorientations in in everyevery moldmold samplesample


MicroscopicMicroscopic stainingstaining methodmethod

2. 2. PolishingPolishing of pellet of pellet samplesample surfacessurfaces-- CrossCross sectionsection cutcut-- AxialAxial crosscross sectionsection cutcut

3. 3. StainingStaining of pellet of pellet samplessamples-- StainingStaining withwith selectiveselective reagentsreagents to to functionalfunctionalgroupsgroups of the of the bindingbinding agentagent ; ; starchstarch --> KI (> KI (potassiumpotassium iodideiodide))-- FlushingFlushing of of extraextra reagentsreagents ((ethanolethanol oror waterwater))-- DryingDrying of the of the samplessamples


MicroscopicMicroscopic stainingstaining methodmethod4. 4. MicroscopicMicroscopic examinationexamination-- ReferenceReference samplesample comparisoncomparison; no ; no bindingbinding materialmaterial usedused

UnstainedUnstained StainedStained withwith KIKI


MicroscopicMicroscopic stainingstaining methodmethodVisual Visual analysisanalysis of of starchstarch containingcontaining pellet pellet samplessamples

UnstainedUnstained StainedStained withwith KIKI


MicroscopicMicroscopic stainingstaining methodmethod5. 5. ConclusionsConclusions of of resultsresults

-- In the microscope pictures starch compounds appear as dark spotsIn the microscope pictures starch compounds appear as dark spots (KI staining)(KI staining)-- Microscope pictures enable to analyze the binding structure of Microscope pictures enable to analyze the binding structure of the the pellet and binding material penetrationpellet and binding material penetration-- OurOur characterizationcharacterization methodmethod cancan bebe usedused for the for the controlcontrol and and developmentdevelopment of pellet of pellet productionproduction ((optimizationoptimization of of correctcorrect feedfeed pointpoint and and mixingmixing of of bindingbinding materialsmaterials))


MicroscopicMicroscopic stainingstaining methodmethod

Publication in progress:

Kuokkanen, M., Prokkola, H., Larkomaa, J., Siltaloppi, L. & Kuokkanen, T. (2009) Characterisation of starch-containing wood pellets by optical microscopic staining method, 24 pp.

Utilization of wood pellet ash

Parameter / nutrient Unit Wood pellet ashpH (1:5) --- 13.3

Electrical conductivity (EC) mS cm-1 58

Dry matter content (105 °C) % 99.7

Loss on ignition (LOI, 550 °C) % (d.w.) 5.3

Total organic carbon (TOC) g kg-1 (d.w.) 57

Neutralizing value (NV) % (Ca; d.w.) 34

Liming capacity* t / t 1,1*

Ca g kg-1 (d.w.) 100

Mg g kg-1 (d.w.) 16.5

Na g kg-1 (d.w.) 5.0

K g kg-1 (d.w.) 70

S g kg-1 (d.w.) 6.7

P g kg-1 (d.w.) 0.08

Mn mg kg-1 (d.w.) 1370

Cu mg kg-1 (d.w.) 23

Zn mg kg-1 (d.w.) 350

Table 2. The physical-chemical properties and the easily soluble nutrient concentrations in the wood pellet ash

* Correspondence between commercial limestone


Metal Wood pellet ash Limit valueForest fertilizer

Limit valueAgricultural fertilizer

Cd 16 17.5 1.5

Cu 160 700 600

Pb 12 150 100

Cr 180 300 300

Zn 640 4500 1500

As < 3.0 30 25

Ni 110 150 100

Hg < 0.03 1.0 1.0

Table 3. Total heavy metal concentrations (mg kg-1; d.w.) in the wood pellet ash and the current Finnish limit values (mg kg-1;

d.w.) for wood-, peat- and biomass- derived ashes used as forest and agricultural fertilizer



The results indicate:

The wood pellet ash is a potential forest fertilizer and neutralizing agent (to substitute commercial CaCO3 )

All total heavy metal concentrations were lower than the current Finnish limit values for forest fertilizer (see Table 3)

Only Cd value was higher than limit value for agricultural fertilizer (see Table 3)

-> Utilization of ash and other industrial residues always need prior approval by the competent authority

Publications:

Kuokkanen, M., Pöykiö, R., Nurmesniemi, H. & Kuokkanen, T. (2009) Wood pellet ash – a potential forest fertilizer and soil conditioning agent (a case study) - The 24rd International Conference on Solid Waste Technology and Management, Philadelphia, PA, U.S.A., 15.- 18.3.2009, 659-667 and a poster.

Kuokkanen, M. and Kuokkanen, T. (2009) Puu- ja turvepellettien sekä hakkeen lämpökeskus- ja pienpoltossa syntyvien tuhkien hyötykäyttöön liittyvä tutkimusraportti - University of Oulu, Report Series in Chemistry, Report No. 74, 45 pp.

Documents

DEVELOPMENT OF WOOD-BASED PELLET PRODUCTION AND …