It depends on whether the product you want is heat or electricity (or both). There are two efficiencies that matter most here: combustion efficiency (how much of the fuel is completely burned) and conversion efficiency (how much of the heat is converted to electricity). It is possible that direct combustion is more "efficient" than pyrolyzation in terms of completeness of combustion. If that's the case and if your desired energy product is heat, or if you can at least use most of the heat, you are correct. It is also possible that even the combustion efficiency is lower for direct combustion, i.e. more non- or partially-combusted carbon is left over, even though it is in a less useful form.
If you want electricity, then the conversion efficiency matters. The gasification products mean you can use a more efficient gas turbine rather than a steam cycle, and a biomass-powered steam cycle is unlikely to be as hot or efficient as one for, say, coal. The difference here can be huge- we might be talking 20% vs. 60% conversion efficiency. That means you get less heat and more electricity, even though you have char (carbon) left over. -- Rich On Fri, Aug 7, 2009 at 4:58 PM, Jon Bosak<[email protected]> wrote: > Ryan Hottle wrote: >> >> 2) Pyrolyzation of biomass is under many circumstance more >> efficient than direct combustion and can additionally produce >> electricity and biochar. > > I'm not clear on how this works. (I'm not quarreling with the > statement; I just don't understand it.) > > Basically the energy is coming from the oxidation of carbon, > right? So if some of the carbon stays carbon, wouldn't that mean > less net energy out? > > Jon _______________________________________________ For more information about sustainability in the Tompkins County area, please visit: http://www.sustainabletompkins.org/ RSS, archives, subscription & listserv information for: [email protected] http://lists.mutualaid.org/mailman/listinfo/sustainabletompkins Questions about the list? ask [email protected] free hosting by http://www.mutualaid.org
