[quote Jack Straw, post: 53245, member: 23"]I asked Siri Is hydrogen in wood? Answer yes, a lot of it[/quote] Lol, quite helpful
Siri said 270 BTU/cu.ft. @ 14 PSI or 1 BAR (atmosphere) @ 60 degrees F. 1 cu.ft. = 28.3L 270BTUs/28.3L= 9.54BTU/L So I am guessing a chitful
I read somewhere that in order to have complete combustion (blue flame) there needs to be a 2:1 ration between hydrogen and oxygen. I was curious about the compounds of wood. I have also read that various woods have different degrees of the compounds. The problem is I can't really get any definitive answers. Where I am going with this is...maybe the amount of secondary air needed in a build is determined by the type of wood being used???
I think wikipedia shows about 14% hydrogen but it doesn't break it down into different species. Nitrogen was the highest at 50% and oxygen was lowest. I think I googled "gases in wood" Gary
Wood, on average, has an elemental composition of 50% carbon, 44% oxygen, 6% hydrogen, and trace metal ions. The two major chemical components are lignin (18-35%) and carbohydrate (65-75%). Hydrogen has 60,000 BTU's per lb however, that's for liquid H. I believe its the celluloses and lignin in those beautiful H-C-O chains that give us the reaction we all are so fond of here.
You can start with this.. then move on to more advanced topics.. Saying that "Hydrogen has a BTU content of XXX per Lb" and then trying to relate that to the percentage of Hydrogen in wood is misleading. The energy from burning wood is gained by breaking the bonds of the wood molecules and combining the atoms with oxygen to make Carbon Dioxide and Water (very simplified). Some of that oxygen can come from the wood and the rest comes from air fed to the fire. The energy that is released is dependent on the molecule being broken down and the energy stored in that molecule. I'm no organic chemist, so I'm going to stop there as I'm operating waaaaay out of my league.
Some more.... http://www.youtube.com/watch?feature=player_detailpage&v=SV7U4yAXL5I http://www.youtube.com/watch?feature=player_detailpage&v=ZsY4WcQOrfk
You can say that again, especially when you consider the process of seasoning (drying) wood significantly lowers the hydrogen content of wood.
Hydrogen - whatever... I'm only concerned about Methane, and it's Flammability and my Proximity to a heat source.
Unfortunately, the heat produced by the combustion of hydrogen goes up the stack in the form of water vapor. (I'm getting an uneasy sense of deja vu). "Wood and bark generally contain about 6 percent hydrogen by dry weight. One pound of ovendried wood or bark contains about 0.06 pound of hydrogen. In combustion hydrogen combines with oxygen and forms water vapor. Water is by weight 1 part hydrogen and 8 parts oxygen. Therefore, 0.06 pound of hydrogen in combustion will form 0.54 pound of water. Heat in water vapor formed from hydrogen escapes from heat recovery systems via stack gases." http://www.fpl.fs.fed.us/documnts/fplgtr/fplgtr29.pdf The hydrogen in water doesn't count, it's already been burned.
