It has more to do with complete oxidation/reduction, and in my opinion, surface area of the feedstock.
You'll find that at 1,200 C+, CO2 is almost non-existent, because of its near-complete conversion to CO. That means ~10% of the typical CO2 (a non-combustible dilution) is no longer in the entrained gas flow. Additionally, if you spray H2O in the form of steam into the reaction zone, you'll "crack" that steam at high temps, which also has the added side-effect of lowering nitrogen levels in the gas flow -- also a non-combustible. Charcoal gasification is best for this "cracking" effect, as pure carbon burns hotter with few impurities, and more consistency. There are, however, less BTU's (energy) in pyrolyzed biomass, than in typical dried biomass. There is no free lunch for high-temperature gasification. It all depends on which aspect of the "holistic lifecycle" is most important. Troy -----Original Message----- From: Gasification [mailto:[email protected]] On Behalf Of Gao Pronove Sent: Sunday, September 14, 2014 7:27 PM To: [email protected] Subject: [Gasification] Low and high temp gasifiers There seems to be a split between low temp gasifiers (700 C and below) and high temp (1,000 C and above). The high temp group claims to have cleaner gas because they "burn" off most of the hydro carbons while the low temp leave a lot of tar in the gas. Is this the common view? Thanks _______________________________________________ Gasification 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/gasification_lists.bioenerg ylists.org for more Gasifiers, News and Information see our web site: http://gasifiers.bioenergylists.org/ _______________________________________________ Gasification 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/gasification_lists.bioenergylists.org for more Gasifiers, News and Information see our web site: http://gasifiers.bioenergylists.org/
