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smallest wood diam?

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by jklingel, Oct 23, 2007.

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  1. jklingel

    jklingel Feeling the Heat

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    A couple more things.... (1) I have been reading that the gasifiers (some/many?) do not require splitting the wood, and seem to take some pretty large diameter logs. Is this a reality, or hype? The trees here, mostly birch, some spruce, some cotton wood, do not often get much bigger than 16-18" at the base. Will I be splitting a lot, or just burn the logs, if properly dried? (2) Many people will not take "branches" smaller than about 4" diam when they harvest wood, and that seems pretty wasteful. What size is too small? My dad burns ANYTHING in his wood stove, including twigs. thanks again. j

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  2. Eric Johnson

    Eric Johnson Mod Emeritus

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    If it will fit in the door and it's dry, these things will burn it with ease, in my limited experience. Some people say they seem to run better on bigger wood. I cut my own trees, so I have a good mixture of all sizes. Unsplit wood is a lot harder to dry, however. I'd say 2 years minimum for anything of any size (6" or larger).

    My firebox door is about a foot high and 2 feet wide. I don't know why the EKO manual specifies wood no larger than 7 inches in diameter. That's a gross understatement of reality.
  3. Nofossil

    Nofossil Moderator Emeritus

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    If you want a sobering experience, take a 6" diameter hardwood round that has been drying for two years. Split it open and measure the moisture content. I've seen 35%.

    Once you have a bed of coals, almost anything will burn. If you put all large logs, the gasification rate will be less and you won't get as much heat per hour, but it will burn longer. I usually do a mix of large and small. It's the weight that determines the heat. I generally split all my big stuff just to get it drier. Since I have heat storage, a short hot fire is just as good as a long cooler fire.
  4. Eric Johnson

    Eric Johnson Mod Emeritus

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    That's really helpful, nofossil. More ways to tinker around with the boiler this winter!

    I've thrown rounds that I swore were dry (stacked in the barn for a year) into the fireplace and then watched them sizzle. When in doubt--split.
  5. leaddog

    leaddog Minister of Fire

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    I've burnt dried wood chips in mine. After I have a fire going I throw 2 or 3 shovel loads in on top off the wood. They burn really well. I chip the branches after they dry all summer with a old corn chopper that I took the row head off. I left the feed rolls on and it will chop up to 3 in. as fast as I can feed them into it.
    I plan to fool around with some cherry pits this winter. I can get them for hauling here so if I can make them work I just might have to come up with an auto-feed. I saw somewhere on the net where some one made a tram with a auto-feed for chips and it was running well. I don't remember if they were dry or not but if you could auto-feed wet pits or chips that would be great.
    leaddog
  6. Eric Johnson

    Eric Johnson Mod Emeritus

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    I'll have to try the chips. This winter I'm planning to check out a bunch of different stuff, from corn cobs to pellets and now chips. Cherry pits sell for $239 per ton around here, I'm told.

    I wonder about walnut shells. Got lots of those. I've been sweeping up the floor after hauling wood and tossing all the pieces of bark and other woody debris in the boiler. I used to shy away from that with my old boilers because it makes a lot of smoke. But now that's fuel, so it's a treat to clean up around the boiler.
  7. Nofossil

    Nofossil Moderator Emeritus

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    Maybe this should be a new thread - I'm looking for a good way to handle and dry wood chips. I'm thinking about mesh onion bags or some such. Any ideas or success stories? I can get nearly infinite wood chips, but I can't imagine how to handle and dry them safely. We've had nasty fires in this state from improper storage of wet wood chips.
  8. Eric Johnson

    Eric Johnson Mod Emeritus

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    A couple of guys who used to work for the State of Vermont were experts in burning wood chips in gasifiers. One was Jack Dwyer, a forester with the DEP who retired a few years ago. Well, maybe 10. I'm trying to think of the other guy's name. I have a friend up in Middlesex who heats with a chip gasifier. He sells chippers. I'll PM you his number and email when I get my hands on it. The other guy worked for the state, too. I'll eventually think of his name and pass it on.

    Vermont is kind of ground zero for intelligent chip burning. The guys at ChipTec would be another good source of information.

    As I recall from talking to these guys, you can build a false floor with pallets and stiff, fine-mesh fencing and blow air underneath to dry the chips. But I'm not at all sure how deep you can go. A wood-fired rotating drum is the way pellet plants do it.

    I really like leaddog's idea of burning dry chips in the EKO. I could store them in my barn attic and just gravity feed them with a big hose into the firebox. They'd probably dry pretty well up there in the summer, too, cause it gets hot. Actually, the heat off the chimney from my old boiler used to keep it above freezing in the winter. Doubt the EKO will waste nearly as much heat which is good, because I got pretty sick of the ice on the roof. I was about ready to build a sauna up there at one point--right above the boiler room.
  9. jklingel

    jklingel Feeling the Heat

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    I need a number..... Can I effectively burn branches down to 1" diam, as long as they are dry?
  10. Nofossil

    Nofossil Moderator Emeritus

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    You can burn grass if it's dry. The only possible issue is that it will burn quicker and hotter, so the boiler controller will cycle the fan to keep it from overheating. That's probably a little less efficient. That's why I mix bigger stuff with the small stuff. You also need a coal bed - grass doesn't make such good coals ;-)

    I burn lots of wood that is 1" or less. Twigs, wood chips, bark, almost any dry combustible material will work. The more surface area per unit volume, the more smoke and heat it generates.
  11. slowzuki

    slowzuki Feeling the Heat

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    Most chip gasifiers I've seen don't use dry chips, green or semi green only. They keep a pilot burn going to keep the combustion chamber temperature up. Dry chips are harder to regulate the burn rate.
  12. jklingel

    jklingel Feeling the Heat

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    Good info. Thanks a lot. j
  13. Nofossil

    Nofossil Moderator Emeritus

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    I should clarify that when I say that small diameters generate more smoke, I mean wood gas in the gasification chamber. All sizes seem to burn clean and produce no chimney smoke.
  14. jklingel

    jklingel Feeling the Heat

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    Thanks for the clarification. I am going to have to look at there EKO boilers, too. To date, we have no local gasifier retailers, so I guess "help" won't be an issue.
  15. adamm

    adamm New Member

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    I'm looking at an Orlan EKO 25 or 40 to heat my house and shop. In the documents I got from my closest seller, it states that it can burn "wood ranging from sawdust to chunks of wood". Does anyone here have experience burning sawdust? It looks to me like the sawdust would just fall through the nozzle and into the secondary chamber before it gassifies. If burning sawdust with other wood, how much ratio of sawdust to cord wood can be used? The local seller didn't seem confident that it will burn any significant amount of sawdust, however, he has never tried it.

    Thank you in advance for any information,

    Adam
  16. sparke

    sparke Minister of Fire

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    My boiler is just the opposite. It does not burn split wood cleanly. The reasoning I have been given is the way refractory gasifiers work - the smoke reburns in the actual fire box. When you burn splits, the smoke exits too fast to reburn. I can testify this is true. When I start a fire with splits they burn dirty. Large rounds burn very clean once the fire is established, splits do not. So yes the hype is true on certain types of boilers such as Seton, Greenfire, and possibly Greenwood.
  17. Nofossil

    Nofossil Moderator Emeritus

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    I burn small amounts of sawdust and wood debris, but usually only a few pounds at a time. I add a paper shopping bag about 1/4 full after a good coal bed has been established.

    The efficiency tests that they did on the larger EKO in Europe used birch chips dried to 15% moisture.
  18. leaddog

    leaddog Minister of Fire

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    I have burnt one large gravity box load of chips this winter. I have a good coal bed and then throw 4 pieces of wood in on top. Then I shovel in about 5 or 6 large loads of dry chips in the middle between the nozzels on top of the wood. Alittle of the chips will fall through but not to many if you put it into the center. Sawdust would work the same. It seems like you need wood chunks to keep the coal bed as the chips and other small matter burns up and doesn't leave and coals so you have to replentish the wood for coals. The tarm that I saw pic's of that burnt chips feed them onto a stainless screen just above the nozzel and kept enough so they burnt underneath and didn't burn up thru. It had a scraper bar that kept it level.
    Saw dust will burn in the way I burn the chips and could be burnt in larger quanity if you could come up with a feed system. The problem with any small auto feed system is the back burnproblem and metering.
    This summer I am going to build a stainless grate from some 1/2 in rod I have to just fit over the nozzel and see how this works.
    The ideal would be chunks I think as you could fill the chamber and air still could go thru. I haven't come up with a good way to make the brush into larger chunks. My converted corn chopper makes two small of chips.
    As far a work goes there is more work in the chips the way I'm doing it than wood rounds but I like to clean up the brush.
    leaddog
  19. mikeyny

    mikeyny Feeling the Heat

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    to dry the wood chips maybe you could build a wood fired dryer. I think that post went on, and on, and on. It seems like a big turning barres full of wood chips and a little hot air might work pretty well.
    Mike
  20. Eric Johnson

    Eric Johnson Mod Emeritus

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    Welcome to the Boiler Room, adamm.

    Having a good bed of coals is the key, as nofossil says. About once a week I sweep up the bark and other debris that's accumulated on the floor of my wood storage area, and toss it into the firebox after a good fire gets going. It always burns completely and clean. Nothing drops through the nozzles because they're covered in hot coals. I think you could successfully burn pellets or chips or anything else that is organic and dry enough, if you're so inclined.
  21. Bob Rohr

    Bob Rohr Minister of Fire

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  22. slowzuki

    slowzuki Feeling the Heat

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    From my time drying lumber, Air-dried wood starting from spring is as dry as it will get in about 8 months. After that is just tracks the humidity levels except when frozen.

    With fire wood the trick is it has to be short enough and split enough to dry that much in that time.
  23. adamm

    adamm New Member

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    Thank you for all the responses.

    Leaddog, that is similar to the set up I am looking at. I have good access to saw dust and wood chips, along with some larger pieces of wood. I will need to go back to the local seller and see how a SS grill would look across the nozzle.

    In the Orlan boilers, does all of the ash go through the nozzle, or does some of it stay in the fuel box and need to be cleaned out? I ask because I wonder if a SS grill would prevent the ash from going through the nozzle (if that is what it is supposed to do) when burning the larger fuel.

    Best Regards,

    Adam
  24. Eric Johnson

    Eric Johnson Mod Emeritus

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    My ash all gets into the ash pit through the nozzles, but some people with older Orlan EKOs (Standard, not Super) seem to have trouble keeping the firebox clear of ashes. The older models have a different refractory design at the bottom of the firebox. On mine, I just rake them down through the nozzles as required.

    I don't think you need to worry about a grill for burning small stuff with one of these boilers. I think if you have a sufficient amount of kindling or small firewood splits to get a bed of coals going, you'll be able to fill 'er up with loose stuff and not have a problem. Just a guess based on my limited experience.
  25. Jim Post

    Jim Post Member

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    I've had great results burning small diameter scraps from a local milling company. They make hardwood trim products and have large quantities of scrap wood. Usually bundled in 4'x 4' x10' bales of thin stick (think yardstick size) or loose 1"x 3" x 4" blocks. This stuff is all kiln dried and burns great in my tarm.
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