I agree, my experience is more power with a hotter reaction, with or without introducing water/steam. Someone recently counseled us to move away from the term "crack" for what goes on with water in a gasifier because, he argued, water/steam doesn't 'crack' until it reaches 2200 C. He suggested that reactive C rips the O away from the H. I'm trying to wrap my tiny mind around this. If this is correct, then this may be a more accurate way of expressing the process: As steam that is superheated in the reaction zone passes through the hot glowing char in the surrounding reduction zone, O will be pulled off by the C to form CO and release H. Does that sound right? We don't need the right explanation to experience the increase in gas power from dripping water or spraying steam into the reaction zone, but I would like to understand what is going on if I can.
-----Original Message----- From: Gasification [mailto:[email protected]] On Behalf Of Big Daddy Sent: Sunday, September 14, 2014 9:11 PM To: 'Discussion of biomass pyrolysis and gasification' Subject: Re: [Gasification] Low and high temp gasifiers 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://cp.mcafee.com/d/avndygw91NJ5x6UVxBZBcTsSztNxCXP3ypJ6Xz3dTDS1NJ6Xz3dTC76jqdT66rCzBeUUSgFlKpfUDX105aX2NfWj-dyspkDbosKrlS5yvQDYr4UOFemMVsSg-Pbyb3_nUQsCzByXzTnKnjjphV5xN6X3TbnhIyCHtNzBgY-F6lK1FJ4SMrLObxEVuhhpjKYrKr01DOFeD49l-7N8BzVkDjw0e2qKMM-l9OwXn2eQAXaSPBm0GvaAWsgBnUv4yr8XijIHrelo5O5mUm-wafBite8iHYfyhb7OFeD00joVAQsCzAS2_id41Fr2mQAXaSPBm1Ftd40lGod46Mgd41eh4Cq89-GIq82eQAXbUQdIe6MoclJVqT ylists.org for more Gasifiers, News and Information see our web site: http://cp.mcafee.com/d/k-Kr6x0gdEI8T7ccLIFCXCQrKccTuosjdETsopKY-MedETsopKYMUOrhKUMPsQsFT76O5aJP9_4_o80Fnom9_ivNIjzaAVr3BPqKMIj-A_zoD6l9OS7bCO7SpshovW_6zAQsInsuWZOWqraf8Ie8TouVqWdAkRrKcsG7DR8OJMddFCS3t-hsd7bOabatTztPo0czJ9eO-de8iHYfyhb7OFeD00sdAtF9SlJDaI2V2Hsbvg57OFeD49l-7N8BzVkDjw09IsOqejhOr1vF6y0QJxbqitBrpOH0QKCy0aRc6y3o86y0D8yjd44_lmd417qitBYq6S73tusBs7Wc0jrF _______________________________________________ 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://cp.mcafee.com/d/1jWVIqdEI8T7ccLIFCXCQrKccTuosjdETsopKY-MedETsopKYMUOrhKUMPsQsFT76O5aJP9_4_o80Fnom9_ivNIjzaAVr3BPqKMIj-A_zoD6l9OS7bCO7SpshovW_6zAQsInsuWZOWqraf8Ie8TouVqWdAkRrKcsG7DR8OJMddICS3t-hsd7bOabatTztPo0c-l9QUxaLM-94IvaAWs01MjlS67OFek7qUhSADpmSsGM5jVkDjy4G_3UAiNYGjFM04ShSADpmSsGMbAaJMJZ0kvaAWsgBnUv4ymfBite00CNP9EVd79I5-Aq83iS4JF9SlJDaI3iWq80HkMq8dwwq82sy9cQgjZloQg4tF9SnNErosdE5DXu_pLiME for more Gasifiers, News and Information see our web site: http://cp.mcafee.com/d/5fHCN0SyMzssMO-OCrKrhKUMPtVxNcSztNxCXPX0USztNxCXP3z9J6Xz3dPhODssr8kGTcDYjZww2BtxoDZ9_6NecGjBIendGX2NfWj-dyspkDbosKr8vpBN5x_HYqejhONtNXHTbFFIEYyMUztxXBHEShjlKUNOEuvkzaT0QSMrodTV5MQsL8EIFTudTdw0OeQAXbUQUxaLM-94IvaAWs01MShSADpmSsGMbAaJMJZ0kvaAWsgBnUv4ymfBite00CNP9EVd79I5-Aq83iS4JF9SlJDaI3iWq80HkMq8dwwq82sy9cQgjZloQg4tF9SnNErosdIz1JYaI8 _______________________________________________ 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/
