Ron, Andrew A very rough estimate: Gross Calorific Value (dry basis) for wood pellets is 5.5 kWh/kg or 5,500 kWh/tonne. (4.6 kWh/kg at 10 % MC). (Biomass Combustion and Co-firing Handbook, S.van Loo and J Koppejan (ed), http://www.ieabcc.nl/ )
Fuel to dry wood increases the wood requirement to make a tonne of pellets by about 15%, or 15% x 5,000 = 825 kWh. Electrcial energy for the pellet plants we design is between 130-150 kWhe/tonne. Specific energy for the pellet machine is about 80 kWe. The rest is auxiliary equipment for conveying, sizing, etc. 150 x 5 (energy from wood at 20% efficiency) = 750 kWh. (750/5500 = 14% of GCV) Total 750+825 = 1575 kWh/tonne. 1575/5500 = 29% of GCV Dr. Sahab Sokjansanj, Oak Ridge National Laboratory, and others have done more detailed analyses that have been published in US Department of Energy reports and journals of the American Association of Agricultural and Biological Engineers (ASABE). http://www.esd.ornl.gov/people/sokhansanj/ There has also been significant work funded by the EU in the last five years on pelleting energy requirements. Regards, Tom -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] Sent: Thursday, March 15, 2012 1:15 AM To: Discussion of biomass cooking stoves Subject: Re: [Stoves] Energy loss in making high grade fuels On Wed, 14 Mar 2012 04:28:33 +0000 (UTC), [email protected] wrote: >A widely different number was given by wiki at 2% for pelletizing This was the figure mooted by the pellet die makers when we were involved with setting up in Wales. It was strictly for the pressing operation and took no account of comminuting, drying or conveying the raw material or produce. It is also the electricity required, which if bought from the UK grid has been converted from thermal power at a rate of 30%. AJH _______________________________________________ Stoves mailing list to Send a Message to the list, use the email address [email protected] to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists .org for more Biomass Cooking Stoves, News and Information see our web site: http://www.bioenergylists.org/ _______________________________________________ Stoves mailing list to Send a Message to the list, use the email address [email protected] to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org for more Biomass Cooking Stoves, News and Information see our web site: http://www.bioenergylists.org/
