USING ASH IN A SUSTAINABLE USING ASH IN A SUSTAINABLE SOCIETY, SWEDISH R&D PROGRAM SOCIETY, SWEDISH R&D PROGRAM

2002-20112002-2011

Claes Ribbing

SVENSKA ENERGIASKOR AB

Innsbruck 22-23 mars 2010

www.energiaskor.se www.varmeforsk.se

The Vision of theThe Vision of the Ash Program Ash Program

Combustion Combustion residues are residues are resources in a resources in a sustainable societysustainable society

33

Research program Environmentally friendly uses of none coal ashes1 m€/year since 2002. 40 companies and authorities The Thermal Enginiering Research Institute of Sweden

EnvironmentForestry Geotechnigue Land filling.

• Criteria's

• Expound laws

• Test methods

• Quality control

• Roads

• Surfaces

• Concrete

• Mining

• Dense layers

• Stabilization

• Covering Mine Tailings

• Recycling

•When outtake of energy

• Extra Growth

Results Results

The results are the results from the The results are the results from the scientists.scientists.

The Authorities don't automatically The Authorities don't automatically agree agree

Specially not about the balance Specially not about the balance between between The AIM of None toxic NatureThe AIM of None toxic Nature Using wastes as resourcesUsing wastes as resources

Claes Ribbing, Svenska Claes Ribbing, Svenska EnergiAskor ABEnergiAskor AB 55

Ash content in different Ash content in different fuelsfuels

The Ash Program works with all their ashes The Ash Program works with all their ashes

25% in municipal wastes25% in municipal wastes Municipal waste contains up to 85% of bioenergi - but Municipal waste contains up to 85% of bioenergi - but

is not a subject for this presentationis not a subject for this presentation

5% in peat (can be much more)5% in peat (can be much more) 10-50% in sludge from paper 10-50% in sludge from paper

industryindustry 2-4% in bark, needles and branches2-4% in bark, needles and branches 0,2-0,5% in pure wood0,2-0,5% in pure wood

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BoilersBoilers(the Pictures show (the Pictures show rebuilt rebuilt boilers at Söderenergi) boilers at Söderenergi)

Grate boiler Incinerators and Smaller boilers less than 100 MW All fuels as bark, wood chips industrial+ household Wastes etc 1 100 °CBottom ashes dominate

Powder cumbustionPeat, pellets (coal)≈ 1 200 °CFly ashes dominate

Fluidised bed. All fuels as wood chips, peat, wastes≈ 850 °COften equal amount fly/bottom asheslow NOx

Use of ashes in Sweden Use of ashes in Sweden 20062006

Problem: Many small producersProblem: Many small producers Roads etcRoads etc 200200 kton kton Forestry, Arable landForestry, Arable land 35 35 ktonkton Backfillning to cavities Backfillning to cavities 50 50 kton (APC)kton (APC) Construction on landfillsConstruction on landfills 650650 ktonkton Others, unknownOthers, unknown 175175 ktonkton TotalTotal 1 milj ton1 milj ton ProductionProduction 1,3 milj ton T1,3 milj ton T Construction on landfills will more or less Construction on landfills will more or less

disappear within 10-15 yearsdisappear within 10-15 years

Ashes to forestsAshes to forests A Cd ion from a rottening branch is not better than the same A Cd ion from a rottening branch is not better than the same

ion from returned ash ion from returned ash

Outtake of bio energy Outtake of bio energy (branches and tops) (branches and tops) demands demands recycling of recycling of ashes =(basic) ashes =(basic) minerals to get a minerals to get a sustainable forestry.sustainable forestry.

The ash must be matured before spreading not to “burn” the ground

It is rather costly

Ashes and growth of forestsAshes and growth of forests

In most of Sweden Nitrogen limits the In most of Sweden Nitrogen limits the rate of growth of trees rate of growth of trees at rich forest soils, ashes increases the at rich forest soils, ashes increases the

release of in soil bound N which increases release of in soil bound N which increases the growththe growth

Ditched peat soils need the minerals of Ditched peat soils need the minerals of ashes to get a good growth.ashes to get a good growth.

When the deposition of N is high, When the deposition of N is high, Phosphorus is the limit for growthPhosphorus is the limit for growth

No harvesting

P budget for different harvesting scenariosfor forests in Sweden

Stem harvestingWhole-treeharvesting

(Akselsson et al., 2008)

ConclusionConclusion

When you take out both the stem When you take out both the stem and bio energy in form of tops and and bio energy in form of tops and branches you have to return the branches you have to return the ashes to get a sustainable forestryashes to get a sustainable forestry Otherwise in the long run P and other Otherwise in the long run P and other

elements will be deficient. (not only in elements will be deficient. (not only in Sweden?)Sweden?)

Nordic innovation centreNordic innovation centrereport TR 613 2008report TR 613 2008

A report most of you should intereted inA report most of you should intereted in

GUIDELINE FOR CLASSIFICATION OF GUIDELINE FOR CLASSIFICATION OF ASH ASH

FROM SOLID BIOFUELS AND PEAT FROM SOLID BIOFUELS AND PEAT UTILISEDUTILISED

FOR RECYCLING AND FERTILIZINGFOR RECYCLING AND FERTILIZING IN FORESTRY AND AGRICULTUREIN FORESTRY AND AGRICULTURE info@nordicinnovation.net www.nordicinnovation.netwww.nordicinnovation.net

Claes Ribbing, Svenska Claes Ribbing, Svenska EnergiAskor ABEnergiAskor AB 1313

Dense layers 50/50 of fly ashes Dense layers 50/50 of fly ashes and digested sewage sludges and digested sewage sludges (dry wt)(dry wt)

when when closure of landfillsclosure of landfills

It is dense: <10It is dense: <10-9-9m/sm/s It has an OK shear It has an OK shear

strength >30kPastrength >30kPa It stands It stands

settlementssettlements It is long lasting: It is long lasting:

the biological and the biological and chemical degrading chemical degrading are very, very sloware very, very slow

(High pH, Salts, Low (High pH, Salts, Low perculation)perculation)

Dense layer trails at Dragmossen

The Tveta methodThe Tveta method

After a lot of research workAfter a lot of research work

At the Tveta Landfill they At the Tveta Landfill they use wastes and specially use wastes and specially ashes in all layersashes in all layers

Layer composition for the landfill cover system

1616

Bio/waste ashes in concreteBio/waste ashes in concrete In concrete, bio fly ashes are good fillers In concrete, bio fly ashes are good fillers

and can replace a lot of Portland cementand can replace a lot of Portland cement

Clorides (0,1% Cl in the paste) are a Clorides (0,1% Cl in the paste) are a problem, they corrode the armouring-iron. problem, they corrode the armouring-iron.

Low quality concretes are Low quality concretes are preferred markets.preferred markets.

Bio fly ashes in roadsBio fly ashes in roadsin the sublevelsin the sublevels

Stiffer and stronger roadsStiffer and stronger roads Stabilizes bad/old materialsStabilizes bad/old materials Less material! 1/4!Less material! 1/4! Much better frost heave Much better frost heave

resistantresistant Less maintenanceLess maintenance No measured impact on No measured impact on

environmentenvironment Light weight constructionLight weight construction

..1818

Constructions with fly ashesConstructions with fly ashes

This plant for recycling This plant for recycling of domestic wastes – is of domestic wastes – is a light weight a light weight construction of construction of wood/peat fly ash on wood/peat fly ash on clay soilclay soil

Ports must be dregedPorts must be dreged

Stabilizing dredged material is Stabilizing dredged material is an interesting market an interesting market possibility for different fly possibility for different fly ashes. (photo OY Ramboll).ashes. (photo OY Ramboll).

Constructions with bottom ashesConstructions with bottom ashes

1919

Grate boiler bottom ashes are good road building materialsGrate boiler bottom ashes are good road building materials Even if the test results on water upptake are highEven if the test results on water upptake are high Better the Better the moremore sintered the ash is. sintered the ash is.

Powder bottom ashes are often poorer due too high amount of Powder bottom ashes are often poorer due too high amount of unburnt.unburnt.

Fluid bed bottom ashes are too fine or too narrow sized to be good.Fluid bed bottom ashes are too fine or too narrow sized to be good.

Test methodsTest methods

Bottom ashes shall be tested with functional test

methods as the dynamic triaxial method.

Normal test methods don't suite and don't give justice to weak materials

Modelling of Low RiskModelling of Low Riskto health and environment to health and environment 1/100 000 risk to get damaged1/100 000 risk to get damaged

To get cancer (not to die of it)To get cancer (not to die of it) For one individual in the most exposed groupFor one individual in the most exposed group That leads to very improbable and That leads to very improbable and

conservative scenarios.conservative scenarios. Shall not increase the the amount of undesired Shall not increase the the amount of undesired

impurities above normal variations in the impurities above normal variations in the recipientrecipient

Shall not contaminate the groundwater as to the Shall not contaminate the groundwater as to the TAC-model for landfillsTAC-model for landfills

The critical scenario for low risk using Ashes The critical scenario for low risk using Ashes as 0,5m thick sublevel in roads without other as 0,5m thick sublevel in roads without other

restrictionsrestrictions

Dust on Dust on vegetablesvegetables are are more critical than leaching!more critical than leaching!

20m

Scenario:1/3 of his yearly intake ofVegetables.He hardly washes them.Dust fromBuilding the road +maintenance and demolition

For gravel roads are calculated that ash is not used in the surface layer but some ash reaches the surface through maintenance. Moderate traffic creates dust during 64 years and 5% of the dust is ash.

Modelling gives:Is a low risk for using bioashes i sublevels!

Max contentsMax contentsPbPb CdCd HgHg ZnZn AsAs

Free use Free use due to Sw due to Sw EPAEPA

No riskNo risk

2020 0,20,2 0,10,1 120120 1010

Ashes to Ashes to forests due forests due to Swedish to Swedish Forests Forests AgencyAgency

300300 3030 33 7 0007 000 3030

Low local Low local risk gravel risk gravel roadsroads

1 4001 400 330330 8080 >2,5 >2,5 %%

5555

Low risk Low risk leaving leaving ashes at ashes at the surface the surface exposure exposure 40 dusty 40 dusty days/ydays/y

1 5001 500 6060 6060 > 5%> 5% 1515

Uses shall be given priority Uses shall be given priority when the risk for health and when the risk for health and

environment is lowenvironment is low

Modelling and tests give that Modelling and tests give that most ashes can be used as most ashes can be used as resources in a sustainable resources in a sustainable societysociety

Thanks for your attentionThanks for your attentionclaes.ribbing@energiaskor.seclaes.ribbing@energiaskor.seyou are welcomed to mail meyou are welcomed to mail me

This presentation will be published atThis presentation will be published atwww.energiaskor.sewww.energiaskor.se

The synthesises of the Ash The synthesises of the Ash Programme 2002-2008 Programme 2002-2008 (report 1111) and the (report 1111) and the database ALLASKA are database ALLASKA are published in English atpublished in English at

www.varmeforsk.se

Don´t forget Don´t forget

TR 613 TR 613 www.nordicinnovation.netwww.nordicinnovation.net