Pellets from wood chip

[openspaceman]

. Remember you will need a power station to drive a 55kw motor and the comment of soft start suggests problems with local grid.

 

Too true, I think the Sprout Matador ones which were installed in Bridgend (refurbished) needed a new substation even though they were nominally 300hp and 5 tonne/hour. The thing is you are essentially reducing the volume of a lump of wood to 1/3 of its original size by squeezing all the air spaces out and crushing the fibres, try doing that in a vice. They need to run fairly continuously to get a consistent product and all the pellets have to be expelled at the end of the run or they dry solid in the die, that gave a guy a few days work with a drill afterwards.

[Justme]

Wont you also need a hammer mill to grind up the chips small enough to be pelleted?

[openspaceman]

Wont you also need a hammer mill to grind up the chips small enough to be pelleted?

 

Yes the rule of thumb was that the biggest particle going into the die mustn't exceed 40% of the die diameter.

 

Hammer mills and dryers use a lot of expensive power but it's the capital cost of the equipment that seemed to be the biggest part of the running cost (where the sawdust was essentially free).

[renewablejohn]

Moisture content is critical anything above 12 per cent and you can forget about producing pellets.

[openspaceman]

Moisture content is critical anything above 12 per cent and you can forget about producing pellets.

 

Yes, IIRC the sawdust went in at about 12% and came out at 10 and quite hot.

Pellet making 10 years ago was a bit of a black art, I've not had any experience since.

 

If you leave a bag of pellets open in a cold damp place they revert to sawdust so the fact that it's still a pellet is a good indication it's dry.

 

There were some small scale pellet producers who used modified versions of the old Lister cuber. These were ok pelleting grain and dried grass with a bit of molasses for a binder but didn't reach the pressures the big machines could. To make sawdust pellets they used a binder made from a waste from the paper making industry, something like calcium lignosulphonate which glued the particles rather than depend on hydrogen bonding in the high pressure system, this did increase the ash content.