[Bioconversion] Fireball update #2

[andrew]

On Monday 14 November 2005 06:35, Jeff Davis wrote:
> Dear List,
>
> Bad day in the laboratory.

Don't be despondent

> After the fireballs dry, they fall to pieces 
> when I go to pick them up. I mean the slightest pressure makes them go back
> to dust. Maybe not enough starch or the wrong starch.

Yes it looks like two things are happening, first is that the dust is not 
fitting together properly, so there are still lots of air spaces and next the 
glue is not working properly. I think both are related as the glue needs to 
fill the voids between particles, to give a good glue length between each 
particle. So in order to minimise the amount of glue needed  you need the 
particles to fit together well. This is why I suggested looking at aggregate 
theory, this is well developed in the building trade both to minimise glue 
(lime, plaster or cement) use and to enable a fine finish.

You can play around with this in two dimensions by getting a lot of different 
sized coins and seeing how to minimise spaces between them. 

The balling technique you are using to aggregate lumps of charcoal has no 
inherent compression to force particles together or deform them to increase 
contact compared with extruders or opposed roller briquetters.

AJH