# Anyone looked at making briquettes from woodchips?



## KiwiBro (Jun 30, 2014)

Just wondering if anyone has looked into chipping whole trees or tops and producing briquettes (or whatever you want to call the compressed biomass fire logs), instead of producing split firewood?


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## zogger (Jun 30, 2014)

You mean uniform pressed logs? I remember a discussion where someone was saying it was doable with a modified splitter and some sort of binding agent, but maybe with sawdust, not chips. But..I don't see why you couldn't use dry chips or shavings, either.

I do not know what would be used as a binding agent. It might be listed in the "ingredients" on one of those already for sale fireplace logs, though. Wax maybe, paraffin?


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## KiwiBro (Jun 30, 2014)

zogger said:


> You mean uniform pressed logs? I remember a discussion where someone was saying it was doable with a modified splitter and some sort of binding agent, but maybe with sawdust, not chips. But..I don't see why you couldn't use dry chips or shavings, either.
> 
> I do not know what would be used as a binding agent. It might be listed in the "ingredients" on one of those already for sale fireplace logs, though. Wax maybe, paraffin?


Yes, uniform pressed/extruded logs.
Preferably using just the natural lignins in the wood for binding. Part of the process, if needed, could be grinding the material down to finer sizes than chips, but nice to avoid it if possible.
There are a few machines that take chips or small branches as the feedstock and grind/heat/press and if needed carbonise it into charcoal logs. 

I just wonder if it wouldn't be an overall more efficient and less resource hungry process of creating consistently high quality firewood, by simply feeding a line that might start with, for example, a tub grinder, and end with high BTU firewood bagged and/or stacked on pallets. If we look at all the resources used to produce a cord of split firewood and the BTU's in that, compared with doing it the pressed log way, I wonder how the two would compare on a per BTU basis.


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## zogger (Jun 30, 2014)

KiwiBro said:


> Yes, uniform pressed/extruded logs.
> Preferably using just the natural lignins in the wood for binding. Part of the process, if needed, could be grinding the material down to finer sizes than chips, but nice to avoid it if possible.
> There are a few machines that take chips or small branches as the feedstock and grind/heat/press and if needed carbonise it into charcoal logs.
> 
> I just wonder if it wouldn't be an overall more efficient and less resource hungry process of creating consistently high quality firewood, by simply feeding a line that might start with, for example, a tub grinder, and end with high BTU firewood bagged and/or stacked on pallets. If we look at all the resources used to produce a cord of split firewood and the BTU's in that, compared with doing it the pressed log way, I wonder how the two would compare on a per BTU basis.



Pressing the logs and getting them to stick and look good seems non trivial to me.

I guess it depends on if you already have to do chips in mass quantities or not.

Here is an alternative product, what to do with surplus wood, I don't think it would matter species too much... as you might be able to get just a few big ag customers to take mass quantities at wholesale truck loads, plus hit retail in bags for individual home owner small gardens.

http://en.wikipedia.org/wiki/Biochar


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## KiwiBro (Jun 30, 2014)

zogger said:


> Pressing the logs and getting them to stick and look good seems non trivial to me.
> 
> I guess it depends on if you already have to do chips in mass quantities or not.
> 
> ...


What do you mean by non trivial? It has been done and is being done in commercial processes, existing machinery, making good use of the lignin inherent in woody biomass.

Why would it rely on pre-existing chips? Are you assuming the costs of producing the feedstock would preclude its commercial viability? It would be great to read more about that because I haven't got a clue, hence this thread. 

Are there any small to medium sized and commercially viable uniform log or biochar producers we could learn from?


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## zogger (Jun 30, 2014)

KiwiBro said:


> What do you mean by non trivial? It has been done and is being done in commercial processes, existing machinery, making good use of the lignin inherent in woody biomass.
> 
> Why would it rely on pre-existing chips? Are you assuming the costs of producing the feedstock would preclude its commercial viability? It would be great to read more about that because I haven't got a clue, hence this thread.
> 
> Are there any small to medium sized and commercially viable uniform log or biochar producers we could learn from?



I have only seen those paper wrapped fireplace logs, they look like they have an added ingredient. Maybe they don't, I don't know. If you can mash just chips together and make them stick as-is, so much the better. 

I have never looked at a commercial operation for making the chip logs, nor the bio char, just read about the latter some as it seemed a good thing to do with the one billion dead pines out west from the pine beetle. As opposed to just waiting then having massive forest fires.

If you can come up with a press from your splitter, just try it, see how they come out. Welded up heavy steel box shape?

wikipedia has this

http://en.wikipedia.org/wiki/Firelog

It says the way they do it with sawdust is no paraffin, or with paraffin. I have only seen with the wax kind. Then some other materials are mentioned. I don't see a chip log reference, but sure seems doable.

As to producing the chips as the total feedstock as opposed to using chips that are secondary to the primary wood product..no idea, never owned operated or even seen a tub grinder. I was using a 12" vermeer wood chipper here before it broke, that is my only experience with commercial sized chippers. You get a heaping whole buncha chips fast though if ya got the branches and small trees to feed into the thing. freeking loud.....

I have no idea what a decent tub grinder costs or the operating expenses with it. A lot more than a regular drum chipper I guess, something that would do really large chunks.

OK, marketing, how many manufactured logs can you sell? Would it be competitive with normal cut and split firewood? Say it costs twice as much, but the logs are twice as good and nice and neat and uniform as regular split wood. could you convince normal wood buyers to shell out the extra? 

*Perhaps* it could be automated and you could make firewood logs cheaper than the normal way, but without equipment costs and actually making some prototype pressed chip logs, I can't see how you could make any educated guesses on it, any big scale extrapolations. 

Seems like a cool idea though.


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## Hddnis (Jul 1, 2014)

From the old days





Mr. HE


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## Hddnis (Jul 1, 2014)

Germans do it too.





Mr. HE


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## Hddnis (Jul 1, 2014)

Nice little operation here, looks like start-up investment wouldn't be too bad.




Mr. HE


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## Hddnis (Jul 1, 2014)

You could make pallets too!




Mr. HE


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## blades (Jul 1, 2014)

Compressed wood log, on a scale that could produce for sale, start up cost from zip = about $100k ( very small production line) , $60 k for a base compression unit, rest for pre and post processing. state side not the biggest market Europe is where 90% of all bio mass produced here is sold. Continuous feed heating units have been installed and tried many times in various countries in EU. From sprayed sawdust to compressed pucks and nuggets( similar to the old coal self feeders of years gone by) Most have not succeeded to well due to regulations requiring certified boiler operators and the ever present EPA type regs. which raise the operating cost to about the same as anything else or in some cases more.. Real overall problem is that total cost of production on a small scale exceeds return revenue state side. Most common binding agent ( regardless of company hype) is corn starch. Got a fair amount of research time in this. both in pellets and blocks or extruded. To exclude binding agent and only rely on lignin requires raising supply material to apx 190 degF. Moisture content of base material must be closely regulated at about 8-12% . Several large concerns are in production as we speak down south and out east, most of their production goes to EU.
Common cattails have a very high lignin content and make an excellant stand alone base material, switch grass is another. Switch grass requires large acreage competing with corn, cattails its a harvesting problem. The average tree service chipped material is a poor candidate due to foreign materials that would/could damage compression equipment same for a lot of the pallet companies or other wood working services. On a basis for your self, base cost for a pellet assembly capable of compressing any type of wood is $4k for the mill ( chi com mfg) + apx $2k for a unit to reduce material to 4-6mm bits. I do not know what the base price is for a presto log unit but it is about the least expensive out there.
An example of low compression coarse material with a wax base for a binder would be Super Cedars. Bio Bricks or Envi - bricks would be saw dust stye high compression no binding agent. some of the fire logs due contain a wax binder such as Pine Mountain brand ( extruded)

Hope this sheds a little light., Awful lot of hype on the web- lot of mis-information as well. As of the end of last winter cost of compressed blocks by the ton vs split wood cord was a horse apiece in my area. But if I am purchasing same I might just as well turn on the natural gas unit and not have any inconvenience.


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## KiwiBro (Jul 1, 2014)

blades said:


> Hope this sheds a little light., Awful lot of hype on the web- lot of mis-information as well. As of the end of last winter cost of compressed blocks by the ton vs split wood cord was a horse apiece in my area.


Many thanks for this blades.
Have you looked at the torrefaction plants making charcoal briqettes and biochar? The claims are the syngas from the pyrolysis powers the plant or at least the heating unit.
Here in NZ we've got a crowd who claim to have mastered microwave pyrolysis and are producing coking coal for steel makers.

Just to clarify, are you saying a ton of compressed blocks is selling for roughly the same as a ton of split wood, or a cord of split wood? If the latter that leads to the obvious questions of moisture content and weight per cord of the cord of the split wood?

Also, who has burned these commercially available compressed blocks and how do they compare to the split wood they are used to using in terms of ease of use, heat produced, time to burn, ash produced?

The cost to reliably produce commercially looks like a problem. $100k in gear is fine if it really knocks out great product and there is or could be a great market for them with buyers willing to use them.

There are a few mobile units now, with the idea being just park a 20' container on or near a landing, a tub grinder next to it, feed whole (or close to) trees into it which feeds a hopper which feeds the brick plant and it spits out bricks at the other end of the container. What this doesn't allow for though is the benefits of leaving biomass on the forest/plantation floor. However, it is assumed far more biomass ends up in the product stream so on a cost per ton of mass harvested, it works out cheaper to harvest whole trees and leave no tops or slash. I haven't yet read anything that justifies such a claim though, although it seems plausible.

Further, I can't find exact conversion rates from, say, a ton or even by volume of wood chip to final tons or volumes of compressed bricks of either wood mass or charcoal. That would be interesting, if only to estimate how much merchantable product could result from harvesting a set area. Without that entire forest to final product analysis it's difficult to asses whether higher costs in one area of production are more than recovered in another area of the whole chain.


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## zogger (Jul 1, 2014)

KiwiBro said:


> Many thanks for this blades.
> Have you looked at the torrefaction plants making charcoal briqettes and biochar? The claims are the syngas from the pyrolysis powers the plant or at least the heating unit.
> Here in NZ we've got a crowd who claim to have mastered microwave pyrolysis and are producing coking coal for steel makers.
> 
> ...



On your last question, you already have a good handle on just wood, what it takes to get x quantity merchantable product and what you leave on the ground behind usually. So from the link I posted above, here is a comparison chart for heat value. You'll have to convert it up to cubic meter/cord I guess (Well, it is in weight, so..hmmm..your noprmal wood species you sell I guess) If you are using all your harvest to make logs, no waste then, eh?

Energy content comparison
Firewood 6400 BTU/lb 14.9 MJ/kg
Extruded firelog 1500 BTU/lb 3.4 MJ/kg
Compressed firelog 8500 BTU/lb 19.8 MJ/kg
Palm fibre firelog 10500 BTU/lb 24.4 MJ/kg
Cotton plant firelog 17000 BTU/lb 39.8 MJ/kg


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## rullywowr (Jul 2, 2014)

Reminds me of that looney tunes cartoon where they grind a whole tree down into a single toothpick.


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## blades (Jul 2, 2014)

1 ton of compressed is about equal to 128 cubic ft.( a cord state side, Green that could be up to 6,000 lbs) of splits BTU wise, that's only a rough way to estimate as a cord of splits could have as much as 20% of the area in air gaps.
Ton of raw material, then you need to subtract moisture weight so to make it easy if you lose 50% of raw material weight drying to 8-12% area then it takes 2 ton raw to equal 1 ton of product.
Tub grinder output too coarse so need to add in an additional grinding stage then into some sort of drying system to reduce moisture content to 8-12% ( this is critical) then onto a heated feed system to supply compression chamber with continuous raw material , out put of compression unit to a cooling system then to a packaging system. Now you need some sort of distribution/transport for the product.
I have read up on torrefaction , as applied to coal, syngas as by product in relation to power plant generation systems. Bio char is something I looked at a long time ago but have not kept up with the present status
Used some of the blocks last winter as an experiment compared to the Sugar Maple I had available at that time seemed to pretty close. I was also staying on the safe side quantity wise of blocks in stove as I wasn't quite sure what to expect on the first coupe hours worth of burn. They do run hotter than cord wood at the beginning - faster out gas, with a slightly lower output over the long haul. Benefits of course are the convenience and no mess, less storage area for a given amount and no 2- 3 year drying cycle time and no bugs to worry about. Detraction's, must be stored in a dry place, average home moisture is fine but if packaging is not water tight and they get wet, it is a loss.


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