Re: GAS-L: Cyclone action gasifier

[Arnt Karlsen <arnt@c2i.net>]

On Tue, 30 Oct 2001 18:05:27 +0000, 
kenboak@stirlingservice.freeserve.co.uk wrote in
<20011030180527.BZVJ23209.fep04-svc.ttyl.com@localhost>:

> 
> Gas-Listers,
> 
> Here are a couple of ideas concerning the mechanical 
> processing of wood waste or biomass into a finely 
> divided powder form suitable for an efficient gasifier. 
> 
> Many of you will be familiar with the cyclone type vacuum 
> cleaners which separate out the various sizes of dust into 
> separate containers using a pair of concentrically arranged 
> cyclones (I'm talking Dyson Dual Cyclones here).  The large 

..url?

> particles are separated out first and dumped in the outer 
> container according to their mass, then the very fine dust 
> travels with the column of air into the much smaller diameter 
> inner cyclone which spins out the very fine stuff and collects 
> it in the inner container.

..I suggest several small cyclones, rather than one "big".
Run in series to separate fractions, and in paralell to allow 
big flows thru many small cyclones.

> Well, it occured to me that this is the very thing that we 
> want to happen in a gasifier, sorting out the various 
> charred particles according to size and then delivering 
> only the very fine stuff into the reaction zone - Kalle's 
> gasifier achieved this by using a mechanical grinding "poker" 
> to ensure a constant supply of the finely divided charcoal 
> dust to the gasification zone.
> 
> The cyclone would be made from heat resistant stainless steel 

..keep in mind that the usual "heat resistant stainless steel" 
are made for service in _hot_air_with_oxygen_. Lose the oxygen,
and pepper it with _anything_, and you lose the oxide surface 
that makes the "heat resistant stainless steel", an heat 
resistant stainless steel.  I was quoted "10 minutes" for 
titanium at atmosphaeric pressure 1000C with 1/3 of massflow 
guesstimated as dust and ash.  I was told by this titanium 
metallurgist guru carbon steel would hold up much better, as it 
would be far more resistant in our reducing process environment.

..cyclones can be stomped out in 3 clay layers and fired.
Rather than cut, welded, etc for one big that needs a lot more space.

> and could be preceded by a drying chamber which not only dries 
> the fuel stock in a stream of hot air (or more likely hot nitrogen),
> but chars it to the point of it becoming friable and easily broken 
> up into smaller particles.  I imagine a revolving drum - not unlike 
> that of a washing machine, where chipped wood enters at one end and 
> is tumbled between an inner and outer drum, drying and then charring. 

..a pelletizer?

> If the inner drum is perforated like a cheese grater it can be used 
> to grind down the wood chips to the point where they pass through a 
> perforated screen or mesh and into the cyclone system.
> 
> If such a system was required to power a domestic scale combined 
> heat and power system, then something as simple as a 2hp garden 

..I'd size it as 'grid voltage x main fuse amperage 
plus maximum domestic usage capasity'. ;-)

> shredded could be used to first chip the firewood up into manageable 
> chips prior to the drying drum.
>
> 
> Your comments appreciated,
> 
> 
> 
> Ken Boak.


-- 
..med vennlig hilsen = with Kind Regards from Arnt... ;-)
...who is busy building his appartment in an old slaughterhouse.
  Scenarios always come in sets of three: 
  best case, worst case, and just in case.


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