Obvious sources of biomass for gasification can be found in agriculture. Here in Vietnam most rice hulls, rice straw and coffee husks are either dumped or burned. Vietnam, for example, produces annually about 8.2 million tons of rice hulls and 54 million tons of rice straw. We do not have to consider producing biochar from trees when such huge agricultural biomass is so readily available.
In the gasification of rice hulls, rice straw and coffee husks, the big value, by far, is in the gas that is produced. For example, one kg of rice hulls produces about $0.21 in gas but only about $0.07 in biochar. In other words, biochar comes in at only one third of the value of the gas. Biochar production therefore is a by-product of gas production. But if the the rice hull can be obtained, as is usually the case, free-of-charge, and if biochar can be sold at a nice profit, then gas is produced at a negative cost. Also note that when rice hulls are properly gasified, no smoke is produced. So in producing gas, one earns a profit in the sale of biochar. The big economic driver in this instance is the production of gas. There are people in Vietnam who know nothing about the value of rice hull gas, and they are busy each day making rice hull biochar in crude retorts. These low-temperature retorts emit clouds of smoke that can be seen from miles around. Focusing only on biochar production, these people do a lot of damage to the environment and should be shut down. The biochar that they produce is anything but uniform. For more on this, see: http://dl.dropbox.com/u/22013094/Paper/park.pdf See the section on gasification starting on page 79. I am a big believer in utilizing a multiplicity of approaches with regard to biomass. Thanks. Paul Olivier Vietnam On Wed, Oct 12, 2011 at 6:40 AM, Steve Taylor <[email protected]>wrote: > > > On 11 October 2011 17:55, Fireside Hearth < > [email protected]> wrote: > >> Dear Steve, >> >> I spent most of my adult life teaching people how to heat their >> homes without smoke coming from the chimney, when I see pictures of areas >> where bio char is being made I see horrible air pollution from the fires, >> > > I see "biochar" being used as an excuse for burning to clear land rather > than the emissions generated being considered pollution from the process of > making it. > > Steve > > _______________________________________________ > 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/ > > > -- Paul A. Olivier PhD 27C Pham Hong Thai Street Dalat Vietnam Louisiana telephone: 1-337-447-4124 (rings Vietnam) Mobile: 090-694-1573 (in Vietnam) Skype address: Xpolivier http://www.esrla.com/
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