Dear Pete,
Oh that it were true! Mix a molar equivalent of H2 with ½ mole of O2 and give it a spark. (Hopefully from a safe distance!) Filling balloons with this mixture (apportioning by measuring the approximated spherical diameter and computing volume) and sending them aloft with a sprig of lit cannon fuse in the rubber-banded neck of the balloon, was worth a nice clap of thunder when they exploded 50 off the ground. Lots of energy released. (and a bit of water formed). Going the other direction and changing that bit of water into its elemental ingredients takes at least as much energy. Meaning: a lot! I could mention how much but its sometimes difficult to relate to Joules or BTUs. 350C is hardly squat on the absolute (Kelvin) temperature scale. When some guy (almost always in Florida!) wants to sell you plans for a carburetor for running your car on Oxygen Dihydride just politely decline. Its not going to happen. If it sounds too good to be true Mark From: Gasification [mailto:[email protected]] On Behalf Of Pete & Sheri Sent: Monday, February 4, 2013 11:51 AM To: 'doug.williams'; 'Discussion of biomass pyrolysis and gasification' Subject: Re: [Gasification] mycoremediation of tarry water I probably have no business asking entering into this discussion since I am neither a chemist nor a physicist, but--- Over the last several months I have been trying to learn the truth about the dissociation of the water in my wood chips into Hydrogen and oxygen. I had previously read someplace that it was a pretty simple process. You just heat water to somewhere above 350 degrees C and there you go. Well, lately I have become quite disconcerted as I have read that there are so many other factors that can be involved, that its anybodys guess as to whether it will happen at all. Some of the variables: Pressure Temperature (obviously) Residence time Presence or absence of carbon and form of that carbon. And, apparently, the availability of carbon from other molecules. And apparently, the list goes on and on. So what is an ordinary human with a stratified downdraft gasifier to do to reliably pry enough hydrogen out of the process to make it worth doing? Pete Stanaitis ---------------- From: Gasification [mailto:[email protected]] On Behalf Of doug.williams Sent: Monday, February 04, 2013 11:26 AM To: Arnt Karlsen; [email protected] <mailto:[email protected]> Subject: Re: [Gasification] mycoremediation of tarry water Hi Arnt, You ask: > ..quick question: H2 needs how much longer dwell time than CO? For many years I was locked into H2 formation as only a temperature dependant disassociation, but this has been shown to be incorrect by the continuous gas analysis we have been able to use for the development programme in California. As we increased the output over a range of bed depths, H2 dropped, while CO tended to increase. You could always find a sweet spot for a chosen depth, but H2 formation lagged if you pulled harder. If you increase the bed depths to increase the contact/dwell time, even by say 25mm, the H2 will increase, but then so does bed resistances. Time taken has to be nano seconds, but as you have discovered, a good sneeze can help maintain the bed porosity(:-) There are many ways to skin this cat, but the basics remain the same based on the experience so far. It would be great if gas was only made at a fixed output, then variations of every type could be controlled. Doug Williams, Fluidyne------
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