[Stoves] Meat grinder fuels for TLUDs was Re: wheat husk pellets

[ajheggie at gmail.com]

[Default] On Wed, 12 Jun 2013 15:41:13 +0700,Paul Olivier
<paul.olivier at esrla.com> wrote:

>How durable is a pellet made from boiled starch or clay?

Fairly durable, just look at the charcoal briquettes that are sold,
they seem to hold their form as they burn, mostly these are made with
an opposed roller to form them.

>What is the percentage of starch or clay added?
>What is the cost of these additives?

Elsen Karlstad did a lot of work on charcoal fines and clay, in
essence the raw material was fee, do a search on the archive for
chardust.

>How do these additives affect the moisture content and other properties of
>the pellets?

I don't know but once dry it should make no difference.

>But is this extra cost not worth it in terms of a higher efficiency in its
>final use?

Tom has posted a comprehensive explanation of the bonding, the
advantages of a dry, dense pellet with low ash content are to do with
transport costs and better combustion, less ash to fuse or interfere
with combustion. You can cram more fuel into a tighter space for
controlled combustion.


>If not, then why do companies often make pellets without the use of starch,
>clay or other additives?

Because it's a purer product and cheaper ingredients at the cost of
much higher capital cost equipment and power.

>If ligin plasticizes, does this not make the pellet more hydrophobic?

In theory yes but all these  processes are a black art, it simply
doens't pay to put any more work into the pellet than necessary to
hold it together for the purpose for which it is made. So I suspect
only the outside skin deforms as described, the inner particles as
simply crushed togetehr to eliminate cell and interstital spaces and
then they presumably are close enough to have the hydrogen bonding Tom
describes.

If you don't need to transport the fuel far the costs of running a
pellet mill (high capital investment, relatively high power
consumption, high wear costs) don't stack up compared with the Legacy
type medium density briquette which burns well, has low investment,
uses cheap or waste agricultural residues although it has a high
labour content and needs drying before use.

>How does one get a uniform flow of air in a TLUD using hexagonal logs?
>How does one avoid CO2 formation using hexagonal logs?

I've never tried one TLUD.

AJH