Torrefaction
Torrefaction of
Biomass can be an important energy source.
Process
Torrefaction is a
During the process, the biomass typically loses 20% of its mass (bone dry basis) and 10% of its heating value, with no appreciable change in volume. This energy (the volatiles) can be used as a heating fuel for the torrefaction process. After the biomass is torrefied it can be densified, usually into briquettes or pellets using conventional densification equipment, to increase its mass and energy density and to improve its hydrophobic properties. The final product may repel water and thus can be stored in moist air or rain without appreciable change in moisture content or heating value, unlike the original biomass.
The history of torrefaction dates to the beginning of the 19th century, and
Added value of torrefied biomass
Torrefied and densified biomass has several advantages in different markets, which makes it a competitive option compared to conventional biomass
Higher energy density
An energy density of 18–20
More homogeneous composition
Torrefied biomass can be produced from a wide variety of raw biomass feedstocks that yield similar product properties. Most woody and herbaceous biomass consists of three main polymeric structures:
Hydrophobic behavior
Torrefied biomass has
Elimination of biological activity
All biological activity is stopped, reducing the risk of fire and stopping biological decomposition like rotting.
Improved grindability
Torrefaction of biomass leads to improved grindability of biomass.
Markets for torrefied biomass
Torrefied biomass has added value for different markets. Biomass in general provides a low-cost, low-risk route to lower CO2-emissions.[citation needed] When high volumes are needed, torrefaction can make biomass from distant sources price competitive because the denser material is easier to store and transport.
Wood powder fuel:
- Torrefied wood powder can be ground into a fine powder and when compressed, mimics liquefied petroleum gas (LPG).[citation needed]
Large-scale co-firing in coal-fired power plants:
- Torrefied biomass results in lower handling costs;
- Torrefied biomass enables higher co-firing rates;
- Product can be delivered in a range of GJ/ton) and sizes (briquette, pellet).
- Co-firing torrefied biomass with coal leads to reduction in net power plant emissions.
Steel production:
- Fibrous biomass is very difficult to deploy in furnaces;
- To replace injection coal, biomass product needs to have LHV of more than 25 GJ/ton.
Residential/decentralized heating:
- Relatively high percentage of transport on wheels in the supply chain makes biomass expensive. Increasing volumetric energy density does decrease costs;
- Limited storage space increases need for increased volumetric density;
- Moisture content important as moisture leads to smoke and smell.
Biomass-to-Liquids:
- Torrefied biomass results in lower handling costs.
- Torrefied biomass serves as a 'clean' feedstock for production of transportation fuels (Fischer–Tropsch process), which saves on production costs.
Miscellaneous uses:
- Several guitar builders have used torrefaction to obtain more dimensionally stable wood for guitar parts than traditional kiln-drying or air-drying provides, including Yamaha, Martin, Gibson, and luthier Dana Bourgeois.[8][9]
See also
- Pyrolysis
- Thermally modified wood
- Carbonization
- Miscanthus giganteus § Transport and combustion challenges(contains a detailed description of the inferior combustion qualities of biomass compared to coal, and the positive effects of torrefaction.)
References
- ^ Austin, Anna (April 20, 2010). "French torrefaction firm targets North America". Biomass Power and Thermal. Retrieved February 29, 2012.
- ^ Koukoulas, A.A. (2016). "Torrefaction: A Pathway Towards Fungible Biomass Feedstocks?" (PDF). Advanced Bioeconomy Feedstocks Conference.
- ^ Johnson, Robin (2007). "Torrefaction - A Warmer Solution to a Colder Climate". World Conservation and Wildlife Trust. Retrieved September 30, 2013.
- PMID 23026268.
- ^ "Torrefaction: The future of energy". Dutch Torrefaction Association (DTA). Archived from the original on November 9, 2018. Retrieved February 29, 2012.
- ^ "Torrefaction – A New Process In Biomass and Biofuels". New Energy and Fuel. November 19, 2008. Retrieved February 29, 2012.
- .
- ^ Price, Huw. "ALL ABOUT... TORREFACTION". Guitar.com. Retrieved 13 July 2019.
- ^ Administrator. "MARTIN - The Journal of Acoustic Guitars | C.F. Martin & Co". www.martinguitar.com. Retrieved 2015-10-06.
Further reading
- "Torrefied Wood Powder to Propane"; "About Us". Summerhill Biomass Systems, Inc. Retrieved February 29, 2012.
- Zwart, R.W.R.; "Torrefaction Quality Control based on logistic & end-user requirements", ECN report, ECN-L–11-107
- Verhoeff, F.; Adell, A.; Boersma, A.R.; Pels, J.R.; Lensselink, J.; Kiel, J.H.A.; Schukken, H.; "TorTech: Torrefaction as key Technology for the production of (solid) fuels from biomass and waste", ECN report, ECN-E–11-039
- Bergman, P.C.A.; Kiel, J.H.A., 2005, "Torrefaction for biomass upgrading", ECN report, ECN-RX–05-180
- Bergman, P.C.A.; Boersma, A.R.; Zwart, R.W.R.; Kiel, J.H.A., 2005, "Development of torrefaction for biomass co-firing in existing coal-fired power stations", ECN report, ECN-C–05-013
- Bergman, P.C.A., 2005, "Combined torrefaction and pelletisation – the TOP process", ECN Report, ECN-C–05-073
- Bergman, P.C.A.; Boersma, A.R.; Kiel, J.H.A.; Prins, M.J.; Ptasinski, K.J.; Janssen, F.G.G.J., 2005, "Torrefied biomass for entrained-flow gasification of biomass", ECN Report, ECN-C–05-026.