www.ecn.nl

Torrefied biomass pellets key to establish dense-phase flow feed to entrained flow gasifiers

Michiel Carbo, Carlos Mourão, Guadalupe Aranda Almansa, Jaap Kiel 8th International Freiberg Conference on IGCC & XtL Köln, Germany, 14 June 2016

• Upgrading: Biomass to commodity fuel – Torrefaction: ECN technology available on full scale – New technology for torrefaction of wet biomass: TORWASH

• Combustion: Biomass boilers and co-firing – Fuel behavior during combustion & gasification – Ashes, slagging, agglomeration behavior

• Gasification: Production of power or fuels – Gasification technology: MILENA – Tar removal and product synthesis – Test equipment and expertise to provide services

• Biorefinery: Technology for a biobased economy – Organosolv fractionation into cellulose, hemicellulose, and lignin – Conversion of fractions into marketable products

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ECN main biomass R&D areas

ECN in co-firing and torrefaction

• 20+ years experience in biomass co-firing R&D, identified the potential of torrefaction and played a pioneering role in torrefaction development since 2002

• ECN’s torrefaction technology proven on lab-, pilot- and demonstration scale; Andritz ready for market introduction

• ECN offers: – Complete portfolio of risk mitigating tools/solutions

tailored and validated for various thermal conversion processes (logistics, handling, co-firing, gasification, grate furnaces, etc.)

– Elaborate test infrastructure to assess feedstock suitability for torrefaction, TORWASH and densification ECN 50 kg/h torrefaction pilot-plant

Introduction Torrefaction

Biomass – a difficult energy source

• In view of: – Logistics (handling, transport and feeding) – End-use (combustion, gasification, chemical processing)

• Difficult properties are: − Low energy density (LHVar = 10-17 MJ/kg) − Hydrophilic − Vulnerable to biodegradation − Tenacious and fibrous (grinding difficult) − Poor “flowability” − Heterogeneous

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Bioenergy – major challenge

• Enable decoupling of biomass production and use – Place – Time – Scale

• By converting biomass in high-quality bioenergy carriers (solid, liquid or gas), that: − Better fit in (existing) logistic infrastructures − Allow efficient, reliable and cost effective conversion into electricity and heat,

transport fuels and chemicals

Solve biomass related problems at the source

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Added value of torrefied biomass pellets

• Torrefaction combined with densification enables energy-efficient upgrading of biomass into commodity solid biofuels with favourable properties in view of logistics and end-use

• Favourable properties include high energy density, better water resistance, slower biodegradation, good grindability, good “flowability”, homogenised material properties

• Therefore, cost savings in handling and transport, advanced trading schemes (futures) possible, capex savings at end-user (e.g. outside storage, direct co-milling and co-feeding), higher co-firing percentages and enabling technology for gasification-based biofuels and biochemicals production

• Applicable to a wide range of lignocellulosic biomass feedstock and waste

Torrefaction – What is it?

• Pre-drying to moisture content typically below 15% • Thermal treatment decomposes hemi-cellulose content at 250-300 ˚C • Either in absence of oxygen or at very limited concentrations • Volatile components are partially driven off and are combusted (for

pre-drying and further heating) • Mild torrefaction temperatures do not affect lignin which can be used

as a binder during pelleting

• First used around 1000 A.D. to treat coffee beans, nuts, etc. in Africa • Treatment of wood for construction in the 1980’s in Nordic countries • First plant in France in the late 1980’s • Potential as bioenergy carrier identified early 2000’s

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Torrefied Biomass Properties in Perspective Wood chips Wood pellets Torrefied wood

pellets Charcoal Coal

Moisture content (wt%) 30 – 55 7 – 10 1 – 5 1 – 5 10 – 15 Calorific value (LHV, MJ/kg) 7 – 12 15 – 17 18 – 22 30 – 32 23 – 28 Volatile matter (wt% db) 75 – 84 75 – 84 55 – 80 10 – 12 15 – 30 Fixed carbon (wt% db) 16 – 25 16 – 25 22 – 35 85 – 87 50 – 55 Bulk density (kg/l) 0.20 – 0.30 0.55 – 0.65 0.65 – 0.80 0.18 – 0.24 0.80 – 0.85 Vol. energy density (GJ/m3) 1.4 – 3.6 8 – 11 12 – 19 5.4 – 7.7 18 – 24 Hygroscopic properties Hydrophilic Hydrophilic (Moderately)

Hydrophobic Hydrophobic Hydrophobic

Biological degradation Fast Moderate Slow None None Milling requirements Special Special Standard Standard Standard Product consistency Limited High High High High Transport cost High Medium Low Medium Low

sources: ECN (table, fig.1, 3), Pixelio (fig. 2, 5), OFI (fig. 4)

Abbreviations: db = dry basis LVH =Lower Heating Value

Technology licensed to Andritz

• Industrial demo plant in Sønder Stenderup, Denmark – Operational since 2012 – Capacity 1 ton/hour torrefied pellets

• Strong combination of industry and R&D

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• Demo plant comprises pre-drying, torrefaction and pelletisation

• Blends ECN and Andritz technologies

• Torrefaction pressurized for more effective heat transfer, reduction of equipment sizes

• Torrefaction reactor contains separate zones for final drying and torrefaction

• Torrefaction reactor design suitable to scale up to large single unit capacities

• All individual equipment units built at large-scale

Torrefaction section of the demo plant

Torrefaction demo plant

Torrefaction demo plant

Small-scale outdoor storage

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After 8 days

After 12 days

• High pellet durability essential for improved weather resistance in time

• Slight degradation outer surface; inner content pile intact

Gasification technology selection for CTL/BTL

Biomass gasification technologies

Downdraft fixed

bed Updraft fixed bed Fluidized bed

(BFB/CFB) Fluidized bed

(indirect/alloth.) Entrained flow

(dry-fed) Typical scale (MWth,input)

0.1-2 0.1-10 BFB: 1-50 CFB: 5-200

1-100 >>100

Flagship plants Harboøre (DK) Numerous BFB: Skive (DK) CFB: Lahti (FI) &

AMER (NL)

Güssing (AT) Buggenum (NL) Puertollano (ES)

Hydrocarbons high high high high nil

Tar [g/Nm3] <1 >100 10-30 10-50 nil

Tar dew point <100°C 200-300°C 200-500°C 200-500°C nil

Particles low low high high moderate

N2 in syngas 50% 50% 50% <5% <5%

Cold gas eff. 70% 95% 70% 80% 80%

Energy in ash 10-20% nil 5-10% nil nil 15 Derived from: Gasification 2nd edition (2008) and van der Drift (ECN, 2014)

CTL/BTL requires economy of scale

Entrained flow gasification

• Feedstock pressurisation prior to gasification yields higher efficiencies (total gas volume to be compressed drastically reduced)

• Pressurisation is more straightforward with pulverised fuels than larger fuel fractions

• Pulverised fuels are easily discharged through funnels and orifices of lock-hopper systems and can be transported in dense phase flow

• Pulverised fuels are converted in a timeframe of seconds • High volumetric powder densities required for smaller equipment sizes

and higher cold gas efficiencies

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Fuel requirements gasification technologies

Downdraft fixed bed Updraft fixed bed Fluidized bed Entrained flow

Fuel size - - + - Fuel shape - - + - Fuel strength - - + + Fuel homogeneity + + 0 - Fuel moisture content

- + 0 -

Fuel ash content + + + 0 Fuel ash melting tendency

- - 0 +

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+: relaxed specifications source: van der Drift (ECN, 2014) 0: no specific requirements -: tight specifications Torrefied biomass pellets

Pneumatic dense-phase feeding

Particle morphology

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Coal Torrefied Eucalyptus pellets

White wood pellets

Pneumatic Transport Coldflow (PTC)

Dense-phase feeding (1)

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Source: ECN

3x less fuel in same volume

Geometry changes pneumatic feeding

Dense-phase feeding (2)

• Behaviour explained by fuel characteristics:

• Torrefied eucalyptus require 10% higher mass input to match thermal input of coal

• White wood pellets would require three gasifiers instead of one to achieve same thermal input

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Material d80 (μm) ρbulk (kg/m3) ρparticle (kg/m3) Pulverised coal 275 750 1450

Pulverised torrefied eucalyptus pellets 420 690 1390

Pulverised torrefied spruce pellets 540 500 1370

Pulverised torrefied poplar pellets 485 530 1360

Pulverised white wood pellets 445 480 1360

NUON/Vattenfall Buggenum experience*

• Maximum 70% co-gasification on energy basis achieved at 90% nominal load without major modifications in Buggenum IGCC

• 1200 tons of torrefied pellets during 24 hours trial • Observations:

– Low durability led to significant dust formation – Low durability disadvantageous during outdoor storage – Low Minimum Ignition Energy (MIE) – However, first of a kind larger-scale batch of torrefied wood pellets

• ECN conducted lab-scale test programme to characterise pellets and

provided consultancy to mitigate risks during commercial operation

* Source: N. Padban, Central European Biomass Conference, Jan ’14, Graz 23

Economic evaluation

CAPEX existing CTL plants

• Corrected for scale and inflation (adapted from ECN report Economy of BioSNG plants: https://www.ecn.nl/publicaties/ECN-E--14-008)

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Average: 1350

Input parameters economic evaluation (1)

• Average CAPEX CTL plant: 1350 M USD2015 per GWinput • CAPEX gasification island: 1/3 of total CAPEX • 1.1 USD for 1.0 EUR • Coal price: 3 USD/GJ or 11.9 €/MWh • Torrefied wood pellets price: 7.3 USD/GJ or 29 €/MWh • White wood pellets price: 7.6 USD/GJ or 30 €/MWh

Pellets prices obtained from SECTOR deliverable D3.2: https://sector-project.eu/fileadmin/downloads/deliverables/SECTOR_D3.2_VTT__final.pdf

• Thermal input: 2 GW (output approximately 17,000 bbl/day) • Thermal efficiency CTL/BTL plant: 49% (likely lower for pulverised

white wood pellets due to increased carrier gas flow) • Interest rate: 10% during 20 years

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Input parameters economic evaluation (2)

Case CTL BTL: Torrefied Wood

Pellets BTL: White Wood

Pellets Thermal input GW 2.0 2.0 2.0

Operational hours h/a 8000 8000 8000

BTL efficiency % 49 49 49

Production capacity bbl/day 16878 16878 16878

Fuel heating value MJ/kg 24.0 21.0 17.0

Fuel consumption Mton/a 2.40 2.74 3.39

Fuel price USD/GJ 3.00 7.32 7.58

Fuel price €/MWh 11.88 29.00 30.00

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Results economic evaluation

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Case CTL BTL: Torrefied Wood Pellets

BTL: White Wood Pellets

CAPEX MUSD 2700 2700 4500

Annuity % 11.7% 11.7% 11.7%

Annual investment costs MUSD/a 317.14 317.14 528.57

Variable costs % of CAPEX 2.0% 2.0% 2.0%

Annual variable costs MUSD/a 54 54 90

O & M costs % of CAPEX 3.5% 3.5% 3.5%

Annual O & M costs MUSD/a 94.5 94.5 157.5

Total costs (excl. fuel) MUSD/a 465.64 465.64 776.07

Fuel costs MUSD/a 172.80 421.82 436.36

Total costs MUSD/a 638.44 887.46 1212.43

Production costs USD/gallon 3.60 5.01 6.84

Production costs EUR/litre 0.87 1.20 1.64

Conclusions

• Torrefaction on the brink of market introduction, several production plants in operation/under construction (total output > 0.5 Mton/a)

• Coming years more commercial-scale torrefaction plants will come online

• Torrefied wood pellets offer superior milling and pneumatic transport behavior compared to white wood pellets

• Torrefied wood pellets can reduce BTL production costs over 25% compared to white wood pellets (mainly CAPEX related)

• Torrefied wood pellets offer significant technological advantages and cost reduction potential for production of second generation biofuels

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Thank you for your attention

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Michiel Carbo Innovation Manager Biomass Upgrading Biomass & Energy Efficiency T +31 88 515 47 92 Westerduinweg 3, 1755 LE PETTEN F +31 88 515 84 88 P.O. Box 1, 1755 ZG PETTEN The Netherlands carbo@ecn.nl www.ecn.nl

Financial support of the European Union through the SECTOR project is gratefully acknowledged.