Compressing fresh wood chip into briguette

[ledders666]

Hello,

 

I have been thinking of making an attachment for my log splitter i made, which runs of a 20t ram, to enable me to try and make logs from wood chip.

 

Has any one tried copressing fresh woodchip?

will it hold together?

 

If not I will try it see what happens.

 

I keep looking at the wood chip I tip thinking its a lot of waste, I cut out as many logs as possible but if I can try and make more could be worth it, or it could be a waste of time. not sure yet!

[TTP]

My sad has tried to compress woodchip, doesn't hold to well as it's to big, you can buy a machine that grinds the chip further and using a bonding agent you can compress it, not cheap to set up but I recon you could make a bit of money from waist chip

[TTP]

Meant dad not sad lol

[steve collins]

Only seen joiners sawdust and chip used for pellets and logs the machines are expensive and use a bonding agent which works most of the time but the product must be kept dry or will fall apart. also have heard of them catching fire due to the pressure they run to compress the dust,chip

[openspaceman]

Has any one tried copressing fresh woodchip?

 

Yes and all you'll manage is to squeeze some water out

 

 

will it hold together?

 

 

No

 

 

There are two mechanisms that hold pellets together in the absence of glues, one is the heat and pressure causing the lignin to plasticise and reflow, setting as it cools, softwoods have higher lignin content.

 

The other is similar to how paper holds together, the fibres are so close together that weak (non chemical) hydrogen bonding occurs. Wood with no air spaces between the fibres is about 1.5tonnes/m3. a 1.5 tonne piece of dry softwood will have a solid volume of 3.75m3. So to get the fibres close enough together for hydrogen bonding you have to compress that 3.75m3 to 1m3.

 

...and paper is also heavier than water.

[renewablejohn]

I do it with both briquettes and wood pellets but for briquettes the moisture content has to be below 15% and for wood pellets below 12%. I also reduce the size of the chip by using a hammer mill.

[gensetsteve]

I produce a metre of fine dry softwood sawdust a day when making kindling. I used to give it to someone making briquettes he has packed it in. if anyone wants it nr Andover hants for free I have about 5 metres at the moment.

[Marko]

Any info on why he packed in would be useful?

[renewablejohn]

Any info on why he packed in would be useful?

 

Could be down to price.

 

Market price used to be £250 per tonne for briquettes and wood pellets its now below £180 per tonne at which point it becomes uneconomic for me. I have mothballed my machines at present but will start again when my commercial pv panels have been installed as with free electric it will become viable again.

[County4x4]

Don't think you'd get far with a 20T ram tbh. One of the good things about briquettes is that there's no crap in them - no binders. glues or anything else. I can't remember where I saw the specs but the figure of 80t/in2 comes to mind - though that could have been for extruded briquettes which tend to be denser than pressed, as well as avoiding all the expanding and falling to bits routines.

 

As far as market price - I pay £400 a tonne delivered for Hotties - which in my opinion are the best (UK manufactured) around at the moment. We burn nothing else at home so it's important that we have a product we're happy with - not just something we can flog to other people. This price is exactly the same as a punter off the street would get - but we get a small commission on our pallet sales in return.