[Stoves] Burning wet wood

[Paul Olivier]

Why burn wet wood?
Designing stoves around improperly prepared fuels is a real headache.

The same logic applies to coal.Coal preparation facilities run coal through
centrifuges and other devices to bring down the moisture content.
Every percentage of moisture or ash takes away from the BTU content of the
coal.It is so inefficient to burn dirty coal or coal of a high moisture
content.

Some say that there is no such thing as a bad fuels, just bad stoves. Just
ask anyone in the coal industry if there is any such thing as a bad coal.
They will immediately point to many things that could make coal unfit for
combustion. They will point to things such as moisture content, ash
content, sulfur content, grindability, ash fusion temperature, grain size,
MAF calorific value, volatile matter content, fixed carbon content and much
more. Imagine how inefficient the coal industry would be if it had to
design power stations around each type of bad coal presented to it.

If we prepare fuels correctly, designing stoves is so easy. We focus far
too much on designing stoves and surely not enough on preparing fuels. This
is the big mistake that most funding organizations make in their promotion
of clean cook stoves.

Thanks.
Paul Olivier


On Thu, Jun 13, 2013 at 8:34 AM, Paul Anderson <psanders at ilstu.edu> wrote:

>  Crispin,
>
>
> Some TLUD's heat pretty much all the wood at once (they vary).
>
> Please describe in detail.   I want to know what you call a TLUD in this
> case.
>
> Paul
>
>
>
> Paul S. Anderson, PhD  aka "Dr TLUD"
> Email:  psanders at ilstu.edu   Skype: paultlud  Phone: +1-309-452-7072
> Website:  www.drtlud.com
>
> On 6/12/2013 11:04 AM, Crispin Pemberton-Pigott wrote:
>
>  Dear Dale****
>
> ** **
>
> I believe it is easiest to burn wet wood in a continuous feed fashion. I
> have had some recent experience in Indonesia trying burn wet (pretty damp)
> wood in a TLUD. Some TLUD's heat pretty much all the wood at once (they
> vary). When that happens there is a huge burst of moisture in the
> emissions. This is visible on the HPT data quality check chart as
> depressed∑O2 and ∑CO2 lines (they should depress in synch). The
> evaporation of all the moisture early makes for problems later because then
> the wood it so dry it won’t stop self-pyrolysing. In other words if
> combustion conditions favour wet wood, later they do not favour dry wood
> remaining.****
>
> ** **
>
> Tom has some experience, as does UK-Andrew in burning pretty wet biomass.
> The essential point is to keep the primary combustion zone hot enough to
> run the fire and still evaporate all that moisture. Heat recycling is by
> far the easiest way to do that.****
>
> ** **
>
> Good to hear from you. Any recent experiments to repot? I have missed your
> great lab work.****
>
> ** **
>
> Regards
> Crispin****
>
> ** **
>
> ** **
>
> +++++++****
>
> ** **
>
> Have we ever looked at the question of how to design a stove to burn wood
> that is higher in moisture?  It would seem that this is very important
> practical issue, and that a stove that could burn wet wood would be very
> popular.  What makes a stove burn wet wood well or poorly?****
>
> The only time I remember someone saying something about this was Crispin,
> who I believe said recently that preheating the primary air makes it
> possible to burn wetter wood.  This would be easy with a batch stove,
> harder with continuous feed.  Other than that, I can think of a couple
> things that might help burn wetter wood. ****
>
> ** **
>
> Dale Andreatta ****
>
>
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-- 
Paul A. Olivier PhD
26/5 Phu Dong Thien Vuong
Dalat
Vietnam

Louisiana telephone: 1-337-447-4124 (rings Vietnam)
Mobile: 090-694-1573 (in Vietnam)
Skype address: Xpolivier
http://www.esrla.com/
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