thermal pretreatment of biomass/torrefaction - jaap kiel

www.ecn.nl

Torrefaction – an enabler for biomass gasification

Biomass Gasifica0on Europe 2014 Jaap Kiel Alkmaar, the Netherlands 2 October, 2014

Biomass – major challenge

•  Enable decoupling of biomass produc0on and use –  Place –  Time

–  Scale •  By conver0ng biomass into high-‐quality bioenergy carriers (solid, liquid or gas), that: - BeOer fit in (exis0ng) logis0c infrastructures - Allow efficient, reliable and cost effec0ve conversion into electricity and heat, transport fuels and chemicals

Solve biomass related problems at the source

Torrefaction for upgrading biomass

•  Process parameters –  Temperature: 240-‐320 °C –  Absence of oxygen

Tenacious and fibrous LHV = 9 - 12 MJ/kg Hydrophilic Biodegradable Heterogeneous

Torrefaction

Friable and less fibrous LHV = 18 - 24 MJ/kg Hydrophobic Preserved Homogeneous

Pelletisation

Bulk density = 650-800 kg/m3

Bulk energy density = 12 - 19 GJ/m3

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 – 24 30 – 32 23 – 28 VolaCle maEer (wt% db) 75 – 85 75 – 85 55 – 80 10 – 12 15 – 30 Fixed carbon (wt% db) 16 – 25 16 – 25 20 – 40 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 properCes Hydrophilic Hydrophilic (Moderately)

Hydrophobic Hydrophobic Hydrophobic

Biological degradaCon 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)

Abbrevia0ons: db = dry basis LHV =Lower Hea0ng Value

The added value of torrefaction

• Torrefac0on (+ densifica0on) enables energy-‐efficient (>90%) upgrading of biomass into commodity solid biofuels with favourable proper0es in view of logis0cs and end-‐use

•  Favourable proper0es include high energy density, beOer water resistance, slower biodegrada0on, good grindability, good “flowability”, homogenised material proper0es

• 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 gasifica8on-‐based biofuels and biochemicals produc8on

• Applicable to a wide range of lignocellulosic biomass feedstock, even mixed waste streams

Sdr. Stenderup demo plant

Simplified single line flow sheet; capacity 1 t/hr biomass input (db)

Sdr. Stenderup demo plant Capacity 1 t/hr biomass input (db)

•  The demo plant has been operated successfully in a range of up to 500 hour trials, yielding good quality product

•  Currently, the demo plant is operated on demand, e.g. to produce product for test firings

•  Andritz is in the process of discussing commercial-‐scale systems

•  Andritz is pleased to discuss your requirements

Status

Ready for commercial market introduction

Torrefaction Ready for commercial market introduction

•  Torrefac0on technology in demonstra0on phase with >10 demo-‐units and first (semi-‐)commercial units in opera0on (e.g., Torr-‐Coal)

•  Successful co-‐firing trials, e.g.: –  Amer 9 (Essent, end of 2013)

–  2300 tonne Topell pellets –  5-‐25% co-‐milling –  1-‐4% co-‐firing

–  Studstrup 3 (DONG, March 2014) –  200 tonne Andritz pellets –  Dedicated mill –  33% co-‐firing

–  Helsingin Energia Hanasaaren (March 2014) –  140 tonne Torr-‐Coal pellets –  14% co-‐firing

9

Product quality optimisation Biomass

Torrefac0on

Validated and op0mised solid biofuel

Densifica0on

Logis0cs tes0ng

End-‐use tes0ng

•  Pilot, demo and first commercial plants produce tonne-‐scale batches allowing representa0ve logis0cs and end-‐use performance tes0ng by industry

•  Product quality op0misa0on requires a systema0c, itera0ve approach (2 itera0ve loops)

•  For this purpose, European torrefac0on developers, combus0on and gasifica0on technology providers and end-‐users have joined forces in the EU-‐FP7 project SECTOR

•  + NL project Pretreatment, with involvement of Topell Energy, Torr Coal, Biolake, Essent, NUON, GdF Suez, TU Delm, U Twente, ECN

This project has received funding from the European Union’s Seventh Programme for research, technological development and demonstration under grant agreement n° 282826

The SECTOR project

§  Collaborative project: SECTOR

§  Project start: 01.01.2012

§  Duration: 42 months

§  Total budget: 10 Mio. Euro

§  Participants: 21 from 9 EU-countries

§  Coordinator: DBFZ

www.sector-project.eu

Alkmaar, October 2, 2014


Torrefaction technologies

Produc0on with available demo plant Con0nuous opera0on

Produc0on of 100-‐200 tonnes Specific feedstock

Produc0on with available pilot scale faciliCes Typical test runs 50-‐100 hours

Typical produc0on per test few tonnes 3-‐6 different feedstocks

Moving bed* (ECN) pilot

Rotary drum / Auger (Umeå University)

pilot

Rotary drum (CENER) pilot

Toroidal (Topell Energy)

demo

Different technologies


* And the resulting Andritz/ECN technology, successfully demonstrated in Denmark at a scale of 1 ton/h


Densification: Pilot-scale tests (CENER)

Image © Andritz © Image from Andritz

Date Durability Pine Date Durability Straw

October 2012

88.8 February 2013

84.2

January 2013

92.3 September

2013 94.3

June 2013

94.7 October 2013

96.6

November 2013

95.7 November

2013 97.6

Optimised parameters: •  Particle size of feedstock •  Moisture content of feedstock •  Torrefaction degree of feedstock •  Die diameter/length ratio •  Die rotation speed



Logistics: Outdoor storage and handling tests (EON)

Two outdoor storage piles built in June 2013

Flat-topped pile �  Model the formation of piles after compaction

(though no compaction occurred) �  3 tonnes �  2.34 x 2.36 x 1.5 m3

Peaked-topped pile �  Model the formation of piles after it has been

delivered �  4 tonnes �  2.34 x 2.36 x 1.5 m3

© EON © EON



Logistics: Outdoor storage and handling tests (EON)

§  Pellet durability as function of time

60

65

70

75

80

85

90

95

100

105

0 10 20 30 40 50 60 70 80

Durability (%

)

Time (Days) Peak Middle Flat Middle Peak Surface Flat Surface



End use: (Co-)gasification in EF gasifiers (Vattenfall)

NUON/Vattenfall Buggenum IGCC Plant: •  253 MWe power plant, entered service in 1993 as a

coal gasification demonstration plant, closed in 2013

•  Hard coal as main fuel with continuous co-gasification of saw dust up to 15 wt%

•  Trial (outside SECTOR, but results brought in): •  1200 tonnes of torrefied fuel co-‐gasified with hard

coal in a 24 hours trial •  Mixing rate ~70% on energy basis

Main observations during the trial: •  No big technical challenges during conveying, sluicing and milling of torrefied pellets/coal

blend •  Estimated to be possible to achieve 90% of the plant nominal capacity without major

modifications in the fuel feeding system •  Higher heating value in the pellets connected to better milling properties but less

advantageous dust formation behaviour


ECN torrefaction R&D services In support of product quality assessment and optimisation

•  Lab-‐to-‐pilot scale torrefac0on tests

•  Extensive physico-‐chemical characterisa0on

•  Full logis0cs, storage and end-‐use performance tes0ng: –  Logis0cs and storage tes0ng (e.g., durability, hydrophobicity, biodegrada0on, leachability) –  Safety assessment (e.g., self hea0ng, explosivity) –  Determina0on of milling, pneuma0c feeding and gasifica0on/combus0on characteris0cs

Milling (pulverisation) Milling characteristics similar to coal

-

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

4,500

5,000

- 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

Power consumption (kJ/kg)

dpv (volume-based mean particle size, mm)

wood chips A

beneficiated/densified wood chips A

beneficiated/densified wood shavings B

beneficiated/densified corn stover C

PRB coal

Source: CEATI SOIG 0530 B/C project

Pneumatic feeding Importance of particle morphology and density

Coal

Raw Spruce Torrefied spruce chips Torrefied spruce pellets

•  Fresh wood par0cles fluffy upon milling •  Torrefied chips par0cles s0ll needle-‐shaped but not fluffy •  Torrefied and pelle0sed par0cles much more

“spherical” (and closer to coal) •  Also: density torrefied/pelle0sed wood much larger (not

shown)

Pneumatic feeding Importance of particle morphology and density

0

5

10

15

20

25

0 0.002 0.004 0.006 0.008 0.01 0.012

Pressure drop P 2-‐P

1 (m

bar)

Mass rate (kg/s)

Coal

Spruce 260°C

Poplar 265°C

Spruce 280°C

•  All materials milled with similar power consump0on

•  Milled pellets, mean par0cle size 200-‐350 μm

•  Ambient air as carrier gas •  Ground fresh wood does not

flow at all •  Milled torrefied pellets flow

well •  Flow proper0es dependent on

feedstock, less on torrefac0on temperature

Reactivity Conversion kinetics comparable to coal

0

10

20

30

40

50

60

70

80

90

100

0 500 1000 1500 2000 2500

conversion (% d.a.f.)

residence time [ms]

PRB coal (75-‐200 µm) PRB coal (53-‐75 µm)

woodchips A (300-‐1000 µm) woodchips A (75-‐300 µm)beneficiated/densified woodchips A (300-‐1000 µm) beneficiated/densified woodchips A (75-‐300 µm)

beneficiated/densified woodchips B (300-‐1000 µm) beneficiated/densified woodchips B (75-‐300 µm)

•  Lab-‐scale comb./gas. simulator –  Tflame/furnace = 1450/1300 °C –  [O2]final= 3.8 % vol dry –  (shallow) burner staging (~200 ms)

•  Reac0vity: –  large impact of milling

–  (75-‐300 µm) fresh wood > PRB coal (53-‐75 µm) –  (75-‐300 µm) beneficiated wood ~ PRB coal (75-‐200 µm) –  (300-‐1000 µm) kine0cs significantly lower (fresh and upgraded) –  deeply-‐torrefied/pyrolysed B material: reac0vity very low (at the applied condi0ons)

Source: CEATI SOIG 0530 B/C project

Torrefaction and gasification •  Torrefac0on has significant advantages in the logis0cs chain (wide range of biomass/

waste feedstock converted into high-‐quality solid bioenergy carriers)

•  Torrefac0on is a technical enabler for (dry feed) entrained-‐flow gasifica0on: –  Grindability

–  Par0cle shape and density

–  Energy density and reac0vity

•  Torrefac0on may be a technical facilitator for other gasifica0on processes: –  Increased reliability/availability due to more consistent feedstock quality

–  Posi0ve impact on gasifica0on process (e.g. less (problema0c) tars)

•  Torrefac0on may be an economic/financial enabler for gasifica0on projects: –  Torrefied biomass as supplementary strategic buffer:

–  to increase feedstock supply flexibility / lower cost

–  to improve bankability of gasifica0on projects

Thank you for your attention!

23

Production at ECN of tonne-scale test batches for industrial trials

Special thanks to: •  Colleagues at ECN, Andritz and partners in the SECTOR

project •  NL Min. of Economic Affairs, Andritz, EUDP partners,

SECTOR partners and EU for providing financial support

For more informa0on, please contact: Jaap Kiel Programme Development Manager Biomass T +31 88 515 45 90 P.O. Box 1, 1755 ZG PETTEN F +31 88 515 84 88 The Netherlands [email protected] www.ecn.nl

The research in the SECTOR project has received funding from the European Union Seventh Framework Programme (FP7/2007-‐2013) under grant agreement n° 282826

thermal pretreatment of biomass/torrefaction - jaap kiel

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