Any ideas on what I could add to sawdust as a binder so that I could compress this dust into bricks or blocks to burn in a wood fired boiler ? I'm scared of burning dust as dust . I was thinking of compressing this dust into blocks the size of a five gallon bucket .This dust contains a variety of wood including both solid wood shavings and MDF dust .
Good question. I'd like to add to it. Does anyone have experience burning green sawdust? This is from a band saw mill and is quite course. Usually oak, ash, maple.
Will,
I believe wood pellets relly on their own natural resins that get produced when the rew material is heated in the pressing process. The resins solidify when it cools and binds the wood fibers. Beyond that, trying to do it yourself you might try to do a google search for "wood pellet fuel" and see what you get. There is alot of this done today but I don't know about do-it-yourself stuff.
The pellet machines are pretty $$$ units and I believe generally used by really large companies.
An alternate suggestion, which may or may not help you, is to look into a wood stove that will handle the sawdust. I looked a couple years ago before I moved shops and there was an English stove that would burn sawdust. You would fill the stove, light it, and let it burn. It would also burn hardwoods of course.
Don't remember the name but if your interested I'm sure a little googling would turn something up.
good luck,
JeffD
The pressure needed to bind the resin on its own is beyond any DIY project I think. It really needs alot of heat and pressure to get saw dust to bind together again witout adding anything to it.
Dave and Will,
It is my understanding that wax is not a good idea! It does not burn completely and will leave a residue in the chimney and can be a source for fire in the flue sometime in the future.
What about used motor oil as a binder I experimented with this in the past with some sucess .I stopped when I changed wood stoves .I use to have a top loader and it worked ok if the stove was empty and no fire to begin with .I've consider a thinned down glue but that could get expensive. Chips and shavings from molder and planer is no problem it's the dust that could cause an explosion.My inside collector uses a 55 gallon drum with plastic bags .I was considering leaving the sawdut in the bag and then using a hydraulic cylinder to compress
A wood dust briquetting machine from China that handles 80-120 KG an hour cost about $5000. It compresses and heats the wood to form round "logs". Very effective. Burns nicely. You can get an import broker and have them help you import it for about 8-10% of the total price. We got ours from Andy Wang in China. His email is tmcwoodworking@globalsources.com. You will find he is easy to communicate with and very responsive.
Check out pelheat.com They offer a complete set up for about $50,000. Still kind of pricey. They are in England. A lot of information on the site too.
The briquetting system from China sounds like a good economical solution. A search on briquetting offers some even cheaper presses, but probably too labor intensive.
Hi all, I am looking for a domestic solution. The commercial options are way too expensive. I cut and split my own wood for a log burning Rayburn cooker and for a log burning stove. I generate a moderate amount of sawdust (mostly oak, chestnut and silver birch) and would like to find a cheap/free method of turning this into blocks for burning on either stove.
I was at Woodmizer a few weeks ago and saw the Biomizer saw dust burner. It produces huge BTU's but unfortunately requires very little dust to do it. I need something that will burn it faster. Our helical head shavings are so fluffy we net mountains of waste. I still think the volume reduction benefits of a briquette machine would be awesome.
Odd isn't it? I do not know what else to do with our walnut dust. No one will take it for compost, or anything else and sending it to the landfill is expensive. The days of getting away with open burning is over in our rural area since the Conservation Cops check out all large plumes of smoke and issue hefty fines. I need a more inefficient saw dust burner to get rid of our waste. I am waiting for Woodmizer to come up with a hot water boiler system. The one I saw was only forced air. A boiler could be pipep to the shop, barn, house, and garage as well as potable hot water and steam kiln. Then maybe I could burn up all of my waste.
Dan, did they have any pricing info when you saw the unit? I just took a look at the site and although there is some interesting info on the concept, I couldn't find much info about the furnace(s). Do they offer different sizes?
I'd also love to be able to burn off all my dust and shavings as opposed to carting them to the landfill, especially with nat gas prices on the rise this year. But my guess is this is probably a prohibitively expensive solution for a smaller (2k sq. ft.) shop.
JeffD
we are installing a sawdust burner this weekend. we built it from salvaged parts. it will be heating our dry kiln. in test we have run, the burner produces a constant 185 degrees per burn.
Hunter;
I would like to hear more about the heater system that you set up! 1. Auger set up. 2. Fire box size and materials. 3. What you used for a heat exchanger. 4. is it set up with a boiler? 5. Igniter system? 6. Any pictures? Thank you for sharing! Stephen
Stephen, this is a low tech burner it top loads into burn chamber,bic igniter, it is a slow burn.it also has fire box for larger wood.other than the fact its fired by saw dust an shavings,its your basic hot water heating system.
In response to the original question, corn starch makes a good binder and is what charcoal plants use. High heat can also be used and is used for pellet making.
Gene
Corn Starch with a litte water or just dry? This post has presented a lot of possibilities the log splitter and mold with a gate sounds possible . using a mold the size of a 5 galon bucket ,How much corn starch and how much water?
Years ago I tried using old motor oil as a binder it worked Ok until one day after spraying some finish I filler the old stove full of sawdust and some old oil .I just had told my helper lets get out of here and let this stuff dry.At that point the Door of the stove blew open and sent burning sawdust all the way to the other end of the shop and that was the end of my sawdust burning adventures.
But to be able to use sawdust in a hot water boiler outside the building sounds posible
What is the consensus on MDF and plywood dust?
I make a furnace that burns bulk wet sawdust and woodchips. or any other green material that you can insinerate
It is a clean burning unit and no material preperation needed. The only electricity to make this thing work is a fan to distribute the heat if you need to.
why not look at it the other way:
making sawdust into pellets is a needless expense of energy if it can be avoided.
For the last 9 years I use a combined pellets /sawdust furnace/ burner that will use sawdust directly - I feed an outdoor sawdust tank with 4-6 sackfuls per day of free sawdust and shavings , the burner uses a feeder controlled by a small computer that automatically ensures perfect combustion by exhaust oxygen content . The control box lets me set the max blower speed , important to keep the sawdust in the firezone. I can burn anything from sanding dust to coarse chips, and in the case of need to I can use commercial wood pellets.
The maker has a good EPA rating.
I used to be a millwright in a pellet mill and we used water and vegetable oil with a LOT of heat and a rotary press mill the mills were really pricey but if you used a hydraulic ram and an extruder you can do it that way just break the pieces into chunks
We use any old small cardboard boxes eg fag packets, toilet rolls basically any box that's log size.
Pour in some dust and shavings, ram it down with a piece of wood keep going till the box is full.
We burn these along with logs.
I know it's not practical if you intend to burn large quantities of dust but the outlay is zero which is always a favourite with me.
To get rid of both used motor oil and sawdust I take an empty waxed half gallon (2 litre) milk or juice container and fill with about 3 inches of sawdust followed with about 3-4 oz. of oil contuinuing the process until about half filled when I tamp the layer of sawdust down well with a piece of 2x4 and continue until completely filled up and packed reasonably well. After folding the top closed and left standing vertically for about 10 minutes to soak in, it's ready to light with crumpled paper in a woodstove. Just one will provide close to 2 hours of medium heat depending on the stove size. I have never noticed any oil smell from the chimney outside yet.
Frankly I think used motor oil should be properly recycled - soon enough weŽll have too little, and burning it is obscenely polluting. Saw dust , shavings etc will burn without further effort in the right type burner and stove, with a whiff of blown air, and fed into the fire slowly. Last 10 years I saved natural gas worth 4-6000$ a year for heating a large workshop and house. Even if you donŽt care about pollution , Oil peak , carbon emissions etc , the savings should be enough.
I have a small woodburning stove (4kw) I make sawdust logs & also add any debri I have from log cutting, bark, ivy, twigs etc.
. Take 2 sheets of a tabloid newpaper, wrap round a template log of your desired size & seal base & length with tape (I use free tape from my work but any will do)
. Fill with mixture of sawdust & burnable debri (I usually fill the first third with sawdust, then the rest with a mixture of both.
. Thoroughly tamp down as you fill & then seal other end with tape.
I find these will burn anywhere up to 2 hours & are ideal to add at the end of the night as they will burn slowly overnight keeping the stove going until the early hours.
I'm very seriously thinking about purchasing a wood gasifier. If you haven't heard of this, you should look into it or google search it. How about powering everthing you have with wood..? Search Google for "Wood Gasifier" .. you will be impressed! I was, and I almost got into steam... what a mess. I 've been off the grid with solar and wind for years and now discover that wood gasification would have been better and cheaper...
Gasification is an old process. In WWII many cities in Europe used this process as wood was the only fuel around. The gas is low BTUs compared to natural gas...about half. In Milwaukee, they used coal gas from gasification of coal.
When gasifying, it is my understanding that not all the wood is converted to gas, but there is a lot of pure carbon left. One concern is how to get this residue out of the burner when the burner is cool. Without a fluidized bed, the fuel size and initial MC must be fairly uniform. Also, the gas cannot be allowed to cool much as it will condense, forming what we typically call creosote. Sometimes we use a two stage gasifier in order to get a cleaner gas. I saw one unit where the gas for the initial gasification was passed across the cool, incoming fuel to clean it a bit. Because of the dirty gas, the transportation of wood gas for very many feet is not possible. Similarly, storage is not easy. Also, if wet fuel is used, there will water vapor gas produced too that must be handled. Also, when the unit is shut down, there can be residue issues as things condense to very hard solids, plug lines, grates, etc. All these items can be handled in a gasifier, but do require a bit of special care. Gasification works best with a constant load.
I built a saw dust burner 4 yeasr ago. I burn green dust with up to 60% moisture.
This burner heats my shop that is 2100 sq feet and my house. I was a second class boiler engineer in Ohio. after several changes I came up with the exact design that will work without no burnback.
I am going to shrink the design down to a home unit within the next year. When I get everything in order it will make up prints for this.
Best regards
i think a bucket of water mixed with a small amount of flower would make a harmless glue to mix with shavings and dust to form a block.i am in process of trying out.
The most common adhesive for charcoal briquets is corn starch. For wood dust, often heat and a little moisture and then pressure will be adequate to bind together pellets.
Why not make the sawdust to pellets or briquettes. The high pressure of the press causes the temperature of the sawdust to increase greatly, and the lignin contains in the sawdust plastifies slightly forming a natural "glue" that holds the pellet together when it cools. You even can add some shredded cardboard or newspapers, those material will all help to make wood pellets easier.
Small size pellet mill is not expensive, 15hp residential pellet mill only costs USD940.00, but you will get 100kgs wood pellets each hour. Briquette machine are not recommended, even we have screw briquette extruder for hollow briquettes, hydraulic wood bricks press, because they are more fit for commercial production scale. Their price are high.
But it is important to control the moisture content of sawdust before pelleting. 13% to 17% moisture content will be better to get good quality wood pellets.
I have seen folks on YouTube and in some old WW1/2 era plans of taking a barrel (or paint can) and put a pipe (temporarially) down the center. Cut a hole in the top and bottom of the can/barrel the size of the pipe (think 4-6" dia in a barrel/drum or 2-4" in a gallon paint can. Dampen sawdust and put it in the can/drum. Tamp it down every few inches around the OUTSIDE of the center pipe. Once full (no space at the top) pull out the pipe and put on the top. Now you have a metal cylinder filled with saw dust. Set it aside to dry out till you need heat or until dried out. ... When ready to use, put on a non-combustible surface with air space underneath (a couple of bricks or so, it needs some height for air flow). Put a flue on top to get the gasses out if inside a building. Crumple some paper and put it in the bottom of the sawdust area, and light the paper. When the sawdust catches, it will burn inside the can, and will burn for quite a while, and surprisingly (to me) completely. They said a barrel should burn for about 8 hours (in what I read).
I have found ,if you have 18+moisture a mold an a press you have what it takes to make sawdust an small shaveings, stick together. you will need a heated drying chamber to reduce the moisture.
Yesterday I cobbled together my first attempt at a rocket-wood-dust-stove for purposes of mass heating & dry steam generation:
50g steel outer exhaust down flow drum,
30 g steel dust charge drum ot (wood dust compressed in place),
vertical burn hole formed with a 4.5"OD plastic pipe set in a
steel air supply & fire starting tube 7" ID, with rough fit sealed with earth false floor.
Assembly set on water leveled & stabilized ground (puddled foundation earth)
Test fired last night. Burned well initially without the lid on.
With the lid on the lid did not get hot enough to support secondary combustion of the flue gas and so power the pump of flue gasses downward.
I somewhat expected that since there is a 3" gap between the top of the 50g barrel and the open top of the 30g drum.
That space is needed for pipes to superheat and dry the steam (open flow system arising from a pressure cooker on top of the 50g drum lid) .
A bit of hot steel to facilitate the secondary burn appears necessary.
Just to test that I dropped a bit of screen over the top of the saw dust's burn hole - now the dust burnt clean and hot.
But the burn was not given its secondary burn by the lid so that the down flow of flue gas would be pumped ram-jet style.
Draw was not nearly enough to produce the burn rate my intended use required - even with the lid off.
A right-gapped lid on on the inner 30g drum may do the job of starting and concentrating the burn so that the outer rim of the lid and upper edge of the 50g drum will get hot enough to complete the secondary burn powering the down draft pump. Sound a bit like wishful thinking. I might test that tonight.
My compressed-to-form dust charge collapsed at about 2/3 burnt. That may have been prompted by weight of the screen I used.
I suspect that my saw dust also needs to be drier and more uniform in moisture.
I would sure like to get it right for this evening test burn. Any insights or guesses will be greatly appreciated. TIA.
Since the burn face and its tube diameter grows as the dust charge is consumed it seems like it should continually work better until its form remains collapse.
Does anyone know if this is true?
I think their must be a limit to that 'better', perhaps some height to diameter ratio because while burn face doubles as tube diameter doubles - tube circumstanced area quadruples.
I saw a link somewhere on a DIY rig made from a electric fire place log splitter. It had a cylinder with part of the side missing with a hopper for dampened sawdust to go into the cylinder. The right compressed it into a long 1" dia or so pellet and just pushed it out the end into a pipe. The pipe guided the continuous 'pellet' through a pipe to the top of a barrel, where a metal 'finger' at the end of the pipe pushed 'down' on the pellet so it would break off into 2 to 3" long pellets (I am sure smaller length if smaller diameter would work). After being compressed, the moisture would heat and evaporate in the process getting the wood saw dust to combine. If being burned in doors, I suggest NOT burning MDF dust (to much plastic in it) or possibly even treated, but other stuff should be able to be burned nicely for domestic heat. ... wish I could find the link. He had an 'automatic shutoff' when the hopper went close to empty or the barrel was close to full.
Found the posting. This is a build blog of an automated DIY briquette press that compresses sawdust. It is not a how-to but most folk should be able to replicate it. He said it takes about 13KW to make a barrel of briquettes. That would be about $1 to $3 in electricity depending on your rates, and his machine runs automatically without supervision. It is left to the interested reader to change it to produce pellets instead of briquettes ;-)
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