Combustion evaluation of torrefied woodpellets for domestic applications

Transcription

1 Combustion evaluation of torrefied woodpellets for domestic applications Jean-Bernard Michel Industrial Bioenergy Systems group University of Applied Sciences of Western Switzerland, Yverdon Martin Schmid Ökozentrum Langenbruck, CH Centre of Appropriate p Technology and Social Ecology (CATSE) 10 th International ti Conference on Energy for a Clean Environment, Clean Air 2009, 7-10 July 2009 Lisboa, Portugal 1

2 Outline The University it of Applied Science of Western Switzerland Characteristics of torrefied pellets Initial combustion test results (10th June 09) Conclusions Acknowledgements to Energy Center of the Netherlands (ECN) for the provision i of torrefied pellets, and information on their process 2

3 HES-SO University of Applied Sciences Western Switzerland More than students Largest UAS in Switzerland 38 degree programs in 6 areas 2 master programs 27 schools Some employees (2 600 full time positions) 3

4 Energy egyrelated eated R&D activities tesin Yverdon-les- edo es Bains Bioenergy Industrial Systems Combustion control systems Phase change materials and ice slurries (IEA working group) Magnetic cooling Buildings physics and energy Solar energy CFD Production of oil or H 2 from algae 4

5 Relevant references Kristoffer Persson et al. Biomass Refinement by Torrefaction, Energy Technology and Thermal Process Chemistry, Umeå University (1 st July 2009) Jianghong Peng, a Study of Torrefaction for the Production of High Quality Wood Pellets, Ph.D. Candidate, August 23, 2007 (British Columbia) P.C.A. Bergman, A.R. Boersma, J.H.A. Kiel and W.L. van de Kamp - Combined Torrefaction and Densification for Biomass based materials, the Top Process, Ninth International Conference on Energy for a Clean Environment, 2-4 July 2007, Porto Kiel et al. - BO 2 -technology for biomass upgrading into solid fuel pilot-scale testing and market implementation. 16 th European Biomass Conference & Exhibition, 2-6 June 2008, Valencia, Spain Mark Jan Prins, Ph.D. thesis. Eindhoven, Dec. 2004: Thermodynamic analysis of biomass gasification and torrefaction Irmgard Herold, Biomass and Waste to Energy: Trends in Investment in the EU, Biomass Industry Day, 1 st July 2009, Hamburg 5

6 Main (known) large torrefaction projects Energy Center of the Netherlands (ECN), BO 2 process large demonstration plant foreseen Airless Systems, UK/Atmosclear, CH. large projects planned from 130 to 270 kt/y Integro Earth Fuels, Wyssmont process, USA, 88 kt/y Roxborrow, NC Topell, NL, Polow Torbed reactor technology, planned 60 ktons/y in Arnhem (NL) together with RWE. 4Energy Invest (B), 38 kt/y in Ambleve (B) 6

7 Process Principle Raw biomass Drying (to about 20% moisture) Flue Gas recycling/ postcombustion (PCI 2 to 3 MJ/kg) Anaerobic heating 240 C-300 C ΔH positive or zero Torrefied biomass 7

8 Plant scheme (source: Wyssmont) 8

9 Unused biomass potential Most abundant after solar and hydro : Forest residues Green urban and highway wastes Straw, bagasse, agroresidues Anaerobic digestion wastes Rapid growth plants e.g. Miscanthus Giganteus

10 Current forms of processed biomass Pellets: PCI about 16-MJ/kg (~40% of fuel-oil) GJ/m 3 storage (~30% of fuel-oil) Wood chips About 10 MJ/kg 3 GJ/m 3 storage Problems Storage volume Hygroscopic Swelling Disintegration Degradation Dust emissions Transport Feeding systems Storage volume Hygroscopic Moulds Thermal efficiency i

11 ECN pilot plant (NL) Capacity : > 60 kg/h Heating at 240 C-280 C during 15 to 30 minutes without oxygen Tor-gas recycling and postcombustion (PCI. 2 à 3 MJ/kg) 11

12 Torrefaction results from ECN pilot (100 kg/h) Low part view of the pilot Grindability y( (energy = 1/10) Mechanical strength X 2 Non hygroscopic PCI 30% Storage energy density 50% 12

13 Torrefaction yield (several processes) Mass yield ~70% Energy yield ~90% 10% left is partly recovered LCV increase by 30% 16 MJ/kg 20 MJ/kg Moisture content 1-6% Hydrophobic Brittle, 70-90% milling power savings Particle size 4 cm Reduction in transport, handling, storage costs Long term storage possible Better combustion/emissions characteristics? 13

14 Source 1: Jianghong Peng, a Study of Torrefaction for the Production of High Quality Wood Pellets, Ph.D. Candidate, August 23, 2007 (British Columbia) Source 2: Irmgard Herold, Biomass and Waste to Energy: Trends in Investment in the EU, Biomass Industry Day, 1st July 2009, Hamburg Cost analysis Cost item Source 2 Source 1 Vancouver S-Africa Europe Europe Sawdust case Production capacity Product pellets pellets Torrefied pellets (ECN) Costs in /ton product Raw material Pod Production Transport Margin Total ( /ton ) ( /MJ)

15 Experimental combustion facility Hoval Biolyt boiler, 50 kw output Continuous recording of all operational parameters 15

16 Torrefied chips and pellets PCI :19.82 MJ/kg Bulk density: 670 kg/m3 Water content: 5.6 % Energy density: 13.3 GJ/m3 Ash content : 1.14% 16

17 Torrefied vs. untorrefied pellets 17

18 Microscopic analysis of the pellets (confocal microscopy) 18

19 Chemical analysis of the pellets (Din+) ECN data HEIG-VD data Parameter Unit raw poplar Torrefied poplar Torrefied pellet chips chips Swiss measurement Length/width/height g mm 40/30/10 40/30/15 18,5 Diameter mm - - 6,7 Gross density kg/dm3om nm nm 1,13 Water content % (m/m)om 9,23 4,8 5,6 Ash content % (m/m)om 051 0, , ,14 Calorific value, upper MJ/kg dm 18,7 19,8 19,82 Abrasion % (m/m)om nm nm 2,8 Sulfur content % (m/m)om nm nm 0,011 Nitrogen content % (m/m)om <01 0,1 <01 0,1 <03 0,3 Chlorine content % (m/m)om nm nm 0,016 Arsenic mg/kg dm < 2,5 <2,5 < 0,5 Lead mg/kg dm < 5,7 < 5,7 1,2 Cadmium mg/kg dm < 4 < 4 < 0,5 Chromium mg/kg dm < 3,2 < 3,2 8,1 Copper mg/kg dm < 2,4 < 2,4 3,0 Mercury mg/kg dm nm nm < 0,05 Zinc mg/kg dm EOX mg/kg dm nm nm < 1 19

20 Burner and combustion chamber 20

21 Isocinetic particulate sampling 21

22 Ignition behaviour No modification made to the operating parameters Torrefied pellets ignite in the same way or slightly faster than normal pellets 22

23 Start up phase Torrefied pellets stion hase ombu up ph of co tart-u rison s St mpar esults Co re CO_norm* [mg/nm3] NO_norm [mg/nm3] Tflue [ C] Tburner [ C] CO2 [%] O2%[%] Time (hours) Start up phase Normal pellets (resinous) CO_norm*0.01 [mg/nm3] NO_norm [mg/nm3] Tflue [ C] Tburner [ C] CO2 [%] O2% [%] Time (hours) 0 23

24 stion ate ombu dy sta of co Stead rison ts S mpar result Co Steady state Torrefied pellets CO_norm*0.01 [mg/nm3] NO_norm [mg/nm3] Tflue [ C] Tburner [ C] CO2 [%] O2% [%] Time (hours) Steady state Normal pellets (resinous) NO_norm [mg/nm3] Tflue [ C] Tburner [ C] CO2 [%] O2% [%] CO_norm*0.01 [mg/nm3] Time (hours) 24

25 Combustion results - Summary volume combustible state O 2 FG CO NO x filter loadnorm/stand TPE Test [%] [mg/mn 3 ] [mg/mn 3 ] [mg] [m 3 13% O2, 0 C [mg/m 3 13% O2 warm Torrefied up Normal pellets 1.2 Torrefied steadystate warm- 2.1 Torrefied up Torrefied steadystate warm- 3.1 Normal pellets up steadystate Normal pellets steadystate

26 Conclusions Torrefied biomass pellets could become a very interesting i fuel for domestic and industrial i heating Combustion properties of torrefied pellets fired in Biolyt burner with no burner optimisation are very comparable to those of normal pellets Heating time is faster due to higher PCI Future work: more in depth and longer term combustion tests: Particulate sampling and size distribution Ash characteristics Different biomass sources Comparison of Life Cycle Balances 26

27 Acknowledgements Energy Center of the Netherlands (ECN) for the provision of torrefied pellets, and information on their process The company Hoval Herzog AG for the supply of their Biolyt boiler University of Applied Sciences Western Switzerland, HES-SO, Energy technology network of excellence (RCSO TE) for their financial support The Center for Engineering and Technology Transfer of the HEIG-VD for its cofunding. 27

28 A tree has more value than banknotes 28