Hi Jason,
Using a vitreous shield (Dick Gallien's solution) seems functionally sensible but it confuses the heat-transfer analysis a bit. If this is a stove (rather than a char producer or gasifier) where we idealize a clean exhaust, robbed of all of it sensible heat. Hmmm. Are heat recovery coils or perhaps plate heat-exchangers on the exhaust the only way to go? Naturally, all of this deviates a bit from pyrolysis and gasification. I like your targeting of retrofits! Best, Mark From: Gasification [mailto:[email protected]] On Behalf Of Jason Sent: Friday, December 27, 2013 10:48 PM To: Discussion of biomass pyrolysis and gasification Subject: Re: [Gasification] Wood heating in the UK - whole log gasification To all, my experience with top feeding systems is keeping the upper ends of the fuel from pyrolysing too early. A water jacket is a logical solution so the link to the jetstream is interesting for me as I have not come across that before. When taking a look at some of the alternate designs at the bottom of that wikipedia page I am reminded of one discussion with a judge at the wood stove decathlon. He advised of the terrible pollution problem from poorly designed boilers, something I had seen discussed but had not explored in depth. The Alliance For Green Heat is in the thick of combating the problem. When the problem of combustion chambers surrounded by water jackets was explained the problem was immediately apparent, the combustion just doesn't get hot enough or for long enough to be complete. So yes a water jacket but its integration into the design has to be carefully considered. The plans for an ultra clean design are in my head now as a consequence of that discussion :-) Jason On Sat, Dec 28, 2013 at 2:10 PM, Tom Miles <[email protected] <mailto:[email protected]> > wrote: Alex, I was thinking of Dick's Jetstream. He employed a lot of good combustion principles to stick wood burning at a time when we were just migrating from the "tin wonder" wood stoves. I didn't realize that there was a Wikipedia page on it. Thanks Tom From: Gasification [mailto:[email protected] <mailto:[email protected]> ] On Behalf Of Alex English Sent: Friday, December 27, 2013 4:41 PM To: Discussion of biomass pyrolysis and gasification Subject: Re: [Gasification] Wood heating in the UK - whole log gasification Ken, If you haven't already heard of the Jetstream The wood was loaded into a vertical tube which passed through the water jacket into a refractory lined combustion chamber. In this chamber the burning took place and was limited to the ends of the logs. The water jacket prevented the upper parts of the logs from burning so they would gravity feed as the log was consumed. http://en.wikipedia.org/wiki/Jetstream_furnace Not a chimney powered stove. Alex On 27/12/2013 6:47 PM, Jeff Davis wrote: Hi Ken, Thanks for the interest! This is my main unknown as yet, how would a split log combust and pyrolise, if presented to the ember bed, cut end first. I suspect that there would be little penetration of heat axially, directly through the end, because the ring structure presents a tough barrier. Therefore, most burning would have to come radially, and so air nozzles would have to be positioned to act radially on the sides of the log. OK, I should try cutting the wood at 45 deg instead of 90. Interesting! In your design, it looks similar to a Rocket, but with the fuel container near vertical. However, the top loading hatch looks fairly airtight? - so unlike a rocket, there is no air drawn through fuel. The next test run will be at almost vertical and more distance between the tube and grate. This has only run for short periods of time but once it's burning OK I have been leaving it up. In the middle of the door is an adjustable air inlet. It's rusted open because of the nasty acidic coal that was burned in it for a few years. Nevertheless it appears to burn well and produces a healthy amount of good sized charcoal. I would be very interested to know how it copes with a larger log. Perhaps by way of experiment, one could be loaded, instead of the 2" material, to see how it fairs - this would be very useful information. In due time. Best wishes, Jeff _______________________________________________ Gasification mailing list to Send a Message to the list, use the email address [email protected] <mailto:[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] <mailto:[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/
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