I thought the underground burning of a "coal seam" for the extraction of gasses was similar to the past "methods mentioned" ie: blowing air and steam as in coke making. in which case the water gas shift would take place with the cracking of water, This basic process is tried and proved within a "sealed retort." However, as mentioned, a coal seam is not a "perfect retort".the ingress of water or air could make the conflagration uncontrollable with ground water getting "cracked" thus producing the oxygen for uncontrolled combustion and the "pressure build up" of "un refined gasses" which will surface after passing through the strata above which is shown to include a fresh water table. This will not remain fresh for very long with the ingress of creosote. go have a dig around the site of any old gas works where the process was carried out in "sealed retorts". even this was an environmental disaster.
GF -----Original Message----- From: Anand Karve <[email protected]> To: Discussion of biomass pyrolysis and gasification <[email protected]> Sent: Tue, Feb 15, 2011 10:51 pm Subject: Re: [Gasification] 300 Megawatt Power Plant and underground coal fires On Wed, Feb 16, 2011 at 6:08 AM, Thomas Reed <[email protected]> wrote: Dear Kevin and all... the "underground coal fire " is really a continuation of the coal making process, and not a fire at all, since there is no way to get oxygen underground. Dear All, Burning coal breaths, if it is kept in a container having a loosely fitting lid. One can test it in a tin can with a lid, which has not been sealed on the can. Put a small quantity of burning coal into the can and close the lid. The heat of the burning coal causes the air inside the can to expand, causing a part of the air inside the can to be expelled. The reduced supply of oxygen causes the fire intensity to be lowered, resulting into cooling. The air inside the can contracts, drawing external air into the can. With the supply of fresh oxygen, the fire intensity goes up, driving the air inside the can to be expelled. This process of alternate heating and cooling goes on until all the coal has burned itself out. One can imagine a similar process taking place in an abandoned mine, or in a natural coal seam with a relatively porous stratum covering it. Yours A.D.Karve _______________________________________________ asification 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 ttp://lists.bioenergylists.org/mailman/listinfo/gasification_lists.bioenergylists.org for more Gasifiers, News and Information see our web site: ttp://gasifiers.bioenergylists.org/
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