[Bioconversion] Algae binder

[andrew]

On Tuesday 27 December 2005 19:56, Les Blevins wrote:

>
> The reason these would bind together I was told is because of the lignin in
> the materials which turns to a glue like material under heat and pressure.
> Now I don't know if the newspaper shreds had any lignin in them or not but
> of course the sawdust and wood shavings would have lignin in it.

That's basically my understanding for the high density pellets and briquettes, 
the pressure breaks down any structure in the cell walls and the heat 
plasticises the lignin which then flows into any remaining gaps. As the 
pellet cools the lignin returns to a solid state.

The more "woody" the biomass is the more lignin it contains, perceived wisdom 
is that if the heat and pressure are sufficient and the raw material contains 
12% lignin and a low moisture content then it can be pelletised.

Even with the given conditions I am aware of some binder being added, these 
seem to be proprietary secrets but a lignin liquor from paper mills may be 
one source of additional lignin.

I doubt there is much lignin in a simple organism like algae. So any binding 
agent will be something else, in the animal feed industry molasses is often 
an added binder. The potential for a cheap binder is that it may cut the 
power requirement for extruding the pellet, albeit at a loss in bulk density.

Richard Stanley of the Legacy Foundation promotes the partial rotting of 
biomass as a means of increasing the binding of his simple whole biomass 
"agriwaste" cooking briquettes. So simple organic compounds may be good 
enough to glue other particles together.

Andrew Heggie