[Stoves] Understanding TLUDs, MPF and more. (was Re: Bangladesh TLUD )

[Andrew Heggie]

On 10 December 2017 at 16:46, Paul Anderson <psanders at ilstu.edu> wrote:
> Crispin,
>
> A full response will be later.

If so you'll just be wasting electrons into cyberspace, it only needs
a very basic understanding of high school chemistry



 But here are a couple of statements:
>
> 1.  Yes, there is O (oxygen) in carbohydrates.   But those atoms will not
> become available during drying or even during torrification.   So the
> retorts will need to wait until pyrolysis temperatures are reached for any
> internal O to become available.

They won't become available at all as separate radicles


>
> 2.  Inside the retort, even with some ambient O2 present between the pieces
> of fuel at the start, there is no combustion (chemical combinations
> releasing heat from burning of O2) if there is no spark or spontaneous
> combustion.

Well the air in the interstital spaces is trivial  and much will be
dispalced in the initial heating up, any that did survive and any air
in the wood pore spaces, a tiny mass, would react with nascent char as
soon as it was formed as the sponaneous ignition temperautre of char
is quite low, in the low 200C range I would suspect.

>And I think that if such a spark (or flame) came into an
> enclosed retort chamber with a mixture of oxygen and combustible gases, that
> there could be some risk of explosion.

Yes, more properly I think it should be called a deflagration and it
happens in woodchip and pellet stokers on occasion.

Andrew