Has anyone ever tried burning loads of wood chips/splitting scraps? I'm talking having a good bed of coals going and shoveling a few scoops of scraps on top? I used to have a guy who took all my scraps, put them in bags from the feed mill and then throw a couple into an outdoor boiler bag and all. I wouldn't burn the bags, but I would think all those scraps could make useful heat instead of burning them in my firepit just to get rid of them...
Anyone try burning loads of wood chips?
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electrathon
Minister of Fire
I do it all the time. Get the fire hot and toss in a shovel full of them on one side of the stove. Only half way cover the coals or it will go out and smoke a lot. Keep the fire hot and every half hour or so toss more in.
jetsam
Minister of Fire
I have, but I found you have to stir them sometimes with little shavings/sawdust. With bigger stuff like splitter scraps, you do not.
Splitter scraps can start their own fire (I used to save tubs of them for fire starters until I realized I generate multiple tubs per year and use 0.1 per year....) I wouldn't want to try it with sawdust and small shavings- you'd have to keep stirring it.
Splitter scraps can start their own fire (I used to save tubs of them for fire starters until I realized I generate multiple tubs per year and use 0.1 per year....) I wouldn't want to try it with sawdust and small shavings- you'd have to keep stirring it.
Be sure they are dry. A pile of chips can stay damp in the middle for a long time. If you take a large tarp and spread them out in the sun they will lose a lot of moisture in just a couple days.
jetsam
Minister of Fire
I have probably 2 - 55 gallon barrels worth on the floor in the garage - super dry. I might try it...
My fires don't seem to take off as well leaving all the coals in front. I rake them to the front to get them going then spread them out. I might try using fewer splits... put them in the middle and throw a shovelful of scraps on each side. Maybe it'll help me get going faster too, burn won't go as long though. Not an overnight thing...
My fires don't seem to take off as well leaving all the coals in front. I rake them to the front to get them going then spread them out. I might try using fewer splits... put them in the middle and throw a shovelful of scraps on each side. Maybe it'll help me get going faster too, burn won't go as long though. Not an overnight thing...
electrathon
Minister of Fire
I burn sawdust all the time too. Treat it the same, hot bed of coals and put it in on one side, add more after a little bit. burning the scraps does produce heat, but it also makes the mess go away. Seems liked a perfect combination, free heat and mess clean-up.
I do this multiple times a week. I sweep around where the wood is stored, and then dump it in the stove when I load up.
If bark has fallen off the wood before I put it in the stove, I save it in a pile, and use that in shoulder season, too.
Waste not, want not...
If bark has fallen off the wood before I put it in the stove, I save it in a pile, and use that in shoulder season, too.
Waste not, want not...
So I am trying something a little different. I have a buttload of small stuff from last year. 2"-2 1/2" rounds and 3"-4" half logs. I save the big stuff for overnight. I'm building the small logs up in the middle to get them air flow and roaring and piling chips on both sides. The smoke from the chips really fires up the secondaries once it's going good... Be interesting to see how long it produces decent heat before I need to reload.
4 hours before pulling the coals forward to burn down. Still some decent chunks in there too, but temp was getting down there. It'll come up a bit as it burns down then ready to do it once more before the big overnight load... It hit 600 or so and the secondaries were going for over an hour - probably closer to 2 (had to leave for an appt). Good maintaining heat for not using up any "real" wood...
Dry wood chips will burn but they burn different than logs. Logs have voids between them to let in primary combustion air. Wood chips tend to seal those gaps. If the coal bed is hot enough, the wood chips will gasify sending more volatiles into the area above the fire. if there is good hot secondary air the gases will ignite. If its a smoke dragon with only primary air its less likely that the gases will fully combust as the heat gets sucked out of the gases through the steel walls quickly dropping the gas temp to below its ignition temperature and there is no hot fresh air to react with it.
When I throw sweepings from my wood storage into my bottom grate stove the wood seals off combustion air but the refractory on either side of the air port heats the sweepings up and they start to gasify. If I open the the top door, I sometimes hear a whoof noise which is hot unburnt gases suddenly getting enough combustion air to burn. In theory I could add secondary air by an unused port and I could combust the gases but since I mostly am burning the sweepings to get rid of them infrequently its not worth the hassle to retune the burn.
When I throw sweepings from my wood storage into my bottom grate stove the wood seals off combustion air but the refractory on either side of the air port heats the sweepings up and they start to gasify. If I open the the top door, I sometimes hear a whoof noise which is hot unburnt gases suddenly getting enough combustion air to burn. In theory I could add secondary air by an unused port and I could combust the gases but since I mostly am burning the sweepings to get rid of them infrequently its not worth the hassle to retune the burn.
This is my new EPA stove. Hot coal bed, get the small wood pile in the middle burning pretty good and the temperature coming up, then enough chips on each side to smolder and burn but not smother it (2-3 ash shovels worth each side). Not sawdust or a lot of fine particles, splitting scraps and bark chunks. Getting great secondaries. Old smoke dragon is in the garage heading for the recyclers...
Diabel
Minister of Fire
Diabel
Minister of Fire
I get what some of you guys are saying, but I don't have a woodlot at home where I burn. I take tree's down for people and haul logs from wherever I can get them and process them at home when I have time. Better to clean up the mess and use it in the stove rather than hauling it down to the fire pit and burning it there... Same goes for all the chips and chunks in the garage by the piles.
I don't expect to do it a lot once I get caught up, but I have a lot now because it never was worthwhile with the old smoke dragon so it has piled up. I was just sharing what was working pretty well with all the small wood I have now to conserve the bigger "overnight" wood.
Next years wood has a good mix of small stuff too, but I am trying to get far enough ahead (3-4 years)that I don't feel the need to split 4"-5" logs to season so quickly. Now that I'm using less wood it is more feasible; plus I can start burning Aspen I haul home from up north in shoulder season which never gave enough heat in the old dragon.
I don't expect to do it a lot once I get caught up, but I have a lot now because it never was worthwhile with the old smoke dragon so it has piled up. I was just sharing what was working pretty well with all the small wood I have now to conserve the bigger "overnight" wood.
Next years wood has a good mix of small stuff too, but I am trying to get far enough ahead (3-4 years)that I don't feel the need to split 4"-5" logs to season so quickly. Now that I'm using less wood it is more feasible; plus I can start burning Aspen I haul home from up north in shoulder season which never gave enough heat in the old dragon.
kennyp2339
Minister of Fire
One of my ex's uncles had a wood chip furnace for there shop / barn that he use to run, it was pretty interesting, he would call in loads of wood chips in the spring and have them dumped into there covered pavilion, he would take his tractor and periodically turn the chips during the summer so they would dry out, in the winter he would load it into the hopper and away it would go, no idea how many yards or tons of chips he would do in a season, but he was a very smart dude, not much of a people guy and was very satisfied of his chip furnace.
U Maine had a home wood chip boiler design years ago. Worked pretty slick but not many folks wanted a silo attached to their home to hold a load of chips. it had a traveling stoker feeder in the silo and would fire the boiler like a household boiler.
jetsam
Minister of Fire
That's a good idea. Any tree service will be happy to bring you a truckload of (green) wood chips for free. Around here they pay by the truckload to get rid of them...
Or how about a basement full of woodchips and an auger to feed the boiler?
Or a giant vacuum motor that sucks wood chips through a tube up to 25m to the boiler?
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SidecarFlip
Minister of Fire
jetsam
Minister of Fire
The first chip boiler I googled up was bragging about its low turndown ability- all the way down to 300,000 BTU/h!
SidecarFlip
Minister of Fire
Nice setup. Moving floor chip feeder, screw auger feed, storage for 600 ton of chips. 175 horsepower high pressure steam, all computer controlled remotely. When it's running, you can smell it but no smoke at all. Has a precipitator and built in baghouse. It's a Scotchback overfire just like the picture. You could drive by and not even know it's there (other than the large quonset chip storage building.) Very efficient units too. Entirely enclosed in a non descript steel sided building.
Nice thing is, they compensate automatically for feedstock moisture content so they burn green or seasoned chips, any variety, hard or soft. Don't matter Feedrate and combustion air is regulated by various sensors that gauge moisture and output temperature as well as boiler pressure.
I ran it before I retired, or should I say I shovelled the ash out and dumped the baghouse fly ash. It really ran itself. High pressure licence required however.
Nice thing is, they compensate automatically for feedstock moisture content so they burn green or seasoned chips, any variety, hard or soft. Don't matter Feedrate and combustion air is regulated by various sensors that gauge moisture and output temperature as well as boiler pressure.
I ran it before I retired, or should I say I shovelled the ash out and dumped the baghouse fly ash. It really ran itself. High pressure licence required however.
All my woodchips go in the stove, I live in the city so my choices are to put it in the stove or send it to the landfill, so up the stack they go.
There are quite a few institutional wood chip boilers installed around northern New England. I believe Tarm biomass has a few models and there are several manufacturers. I used to work on occasion on the larger bomasss power plants installed around the region that are slowly dying. The hassle with burning chips is chip uniformity, the smaller the boiler the harder it is to meter the fuel flow to the boiler. Most folks think of nice uniform chips that look like square charcoal briquettes. When I went to the biomass shows and saw the small demo units running in the parking lot I would take a look at the chips and wonder where they got them as they were definitely not what I saw in the plants I worked on.
Unfortunately unless someone pays a premium for uniform chips what they get are whole tree chips which include sticks and leaves plus the typical chipper used in the woods tends to shred the wood instead of chip it. Ideally to make a nice uniform chip the chips should be made from the trunks (bole) the same stuff we want for firewood. The uniform chips are great to deal with and flow almost like water, the whole tree chips are nightmare, they get tangled up and clog things. Many a small biomass system owner has learned early on that who and where they get their chips is the most important thing in keeping the systems running. All sort of stories of having to having to have someone stand there 24/7 trying to keep the chips flowing in a supposedly non attended systems. At least one firm in the region got smart and they take make premium chips and handle the fuel supply for a lot of the institutional burners. They owners pay a premium but it cuts the hassle way down.
The problems with non uniform chips is why wood pellets were invented. They are the ultimate uniform wood chip, they are dry so the storage volume is low and no sticks or leaves. Obviously they cost more but they are the way to go for small unattended home systems.
The pulp mill I worked for had a 6 story chip screening facility that could sort chips from a chipper or purchased chips so that the chips going to the pulping process were uniform. It was a Weyerhaeuser licensed system that put out a very uniform chip. Any over sized chips were sorted out and resized, things like sticks and leaves went to our bark boiler. We went through 1100 tons of green wood chips a day so we didnt want clogs in our storage and conveying systems.
Unfortunately unless someone pays a premium for uniform chips what they get are whole tree chips which include sticks and leaves plus the typical chipper used in the woods tends to shred the wood instead of chip it. Ideally to make a nice uniform chip the chips should be made from the trunks (bole) the same stuff we want for firewood. The uniform chips are great to deal with and flow almost like water, the whole tree chips are nightmare, they get tangled up and clog things. Many a small biomass system owner has learned early on that who and where they get their chips is the most important thing in keeping the systems running. All sort of stories of having to having to have someone stand there 24/7 trying to keep the chips flowing in a supposedly non attended systems. At least one firm in the region got smart and they take make premium chips and handle the fuel supply for a lot of the institutional burners. They owners pay a premium but it cuts the hassle way down.
The problems with non uniform chips is why wood pellets were invented. They are the ultimate uniform wood chip, they are dry so the storage volume is low and no sticks or leaves. Obviously they cost more but they are the way to go for small unattended home systems.
The pulp mill I worked for had a 6 story chip screening facility that could sort chips from a chipper or purchased chips so that the chips going to the pulping process were uniform. It was a Weyerhaeuser licensed system that put out a very uniform chip. Any over sized chips were sorted out and resized, things like sticks and leaves went to our bark boiler. We went through 1100 tons of green wood chips a day so we didnt want clogs in our storage and conveying systems.
Ok, maybe I don't have a lot of chips... silo's? 1100 tons? 
I've got enough dry to fill 2 - 55 gallon barrels... and that's probably 2 years of wood pile buildup.
What isn't dry but will be burnable is probably about the same.
What won't be burnable because it's too small or turning to compost at the bottom of the pile will go into the gardens and become zucchini, cantelopes, jalapenos and other assorted produce... Use it all! That's why we eat venison liver too - and I've learned how to make it with nobody complaining...
I've got enough dry to fill 2 - 55 gallon barrels... and that's probably 2 years of wood pile buildup.What isn't dry but will be burnable is probably about the same.
What won't be burnable because it's too small or turning to compost at the bottom of the pile will go into the gardens and become zucchini, cantelopes, jalapenos and other assorted produce... Use it all! That's why we eat venison liver too - and I've learned how to make it with nobody complaining...
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