[Terrapreta] torrified wood vs. charcoal

[Robert Flanagan]

The catch...
The wood is transformed into a more refined fuel, similar to the energy
nature of coal but without any pollution side effect because all *pollutants
have been removed.*
**

Hi Gerald,

So to answer your question, or ask the question "What happens to the
pollutants while it's been turned from wood to torrified wood?" Again I say
why waste all the energy taking biomass to just under it's exothermic curve
just so you can burn it for heat?

A little back ground on pyrolysis "V" gasification,


In pyrolysis your feedstock is typically high in moisture (50%, called green
waste) and little or no oxygen is added during the process (depending on the
process time and desired charcoal) so typically you have a very wet off gas.
There is a direct relationship between temperature, duration, carbon content
and charcoal yield. With slow low temperature pyrolysis (400C) it's possible
to have charcoal yields of around 33% but not much higher with a low carbon
content. When you reach higher temperatures, your charcoal yield can drop to
10-15% (the typical yield for traditional charcoal kilns used in Brazil is
about 15%). The highest possible charcoal conversion obtainable today is via
flash carbonization (http://www.hnei.hawaii.edu/flash_carb_biomass.pdf).

Gasification on the other hand uses biomass with much lower moisture content
(Optimum 20%). The biggest difference between the two is the natural
exothermic jump in the flaming pyrolysis zone. These figures change a bit
for different biomass streams but to avoid confusion, I will keep it simple
and not get too bogged down with the finer details. When you heat up biomass
to around 280C it goes into an exothermic reaction (begins to give off heat)
and the temperature jumps to around 400C. Now this energy jump causes the
next layer of biomass to heat up and also go into the exothermic zone and so
on and so on, until you're left with a pile of char. Now with gasification,
the lowest possible jump is from around 280C to 600C (Depending on air
flow), due to primary air (Fresh oxygen) flowing through the reactor the
whole time (enough to strip the gases off, but not enough to reduce the
carbon to ash). So with gasification stoves we exploit this law and use the
excess energy to crack the gases and water as they pass through this hot
carbon zone. This then provides fuel that we can burn directly whilst also
producing charcoal (wood gas (CH4) + water + high temperature carbon, reacts
as follows H20+C=H2+CO; end gas= (CH4+H2+CO))

 Where gasification is concerned, a 20% charcoal yield is considered high
but you have to remember the higher the temperature of the charcoal the
higher the carbon content, so although you might have less charcoal, your
overall fixed carbon yield might be very close.
Better to get all the energy from the biomass plus the energy from the
hydrogen in the water using a Top Lit Up Draft (TLUD) stove!

Kind regards,
Rob.




 Thu, Feb 14, 2008 at 4:30 AM, Gerald Van Koeverden <vnkvrdn at yahoo.ca>
wrote:

>  No smoke, no VM, no odour, high heat, cheaper than coal, etc.  You can
> even use the gases coming off the process to heat more of it.  What is hard
> to understand about such a 'wonder' stove fuel, is that it has taken so long
> for engineers to find a way to produce it.  Maybe that's the catch...to be
> able to heat it evenly and thoroughly enough while preventing it from going
> exothermic and ending up with charcoal?  Sort of like coitus interruptus...
>
> "the wood is transformed into a more refined fuel, similar to the energy
> nature of coal but without any pollution side effect because all pollutants
> have been removed.  After it has been processed only the energy
> component remains in the wood, the natural smoke forming volatiles have been
> removed and the moisture and ash content is reduced to less than 1%. Through
> ECO densification a higher heat value/energy content is achieved, it is
> then pelletized for transportation.  It is now a renewable fuel that
> resembles the energy component in coal, but where as coal has many other
> pollutants still trapped inside of it, ECO Clean Coal [torrefied wood] has
> been liberated of all pollutants. Therefore, when the ECO Clean Coal is
> burned it is smokeless and odorless. You can burn it indoors and outdoors."
>
> http://www.techtp.com/ECO_Clean_Coal_brochure.pdf
>
> Begin forwarded message:
>
>  *From: *Gerald Van Koeverden <vnkvrdn at yahoo.ca>
> *Date: *February 13, 2008 12:14:05 PM EST (CA)
> *To: *Robert Flanagan <saffechina at gmail.com>
> *Cc: *Terra Preta <terrapreta at bioenergylists.org>
> *Subject: **Re: [Terrapreta] torrified wood vs. charcoal*
>
> Rob,
> I went to that "youtube" site.  a lot of cool neat stoves...I will ponder
> your suggestion.
>
> Whatever, for more information about torrefied wood, I found a website
> dedicated to it:
>
> http://www.techtp.com/
>
> Gerrit
>
>
>  On 12-Feb-08, at 10:16 PM, Robert Flanagan wrote:
>
>  Hey Gerald,
>
> Why would you cook on torrefied or charcoal when you can burn the smoke
> and woodgas with a Top Lit Up Draft gasifier and keep the charcoal?
>
> http://www.youtube.com/results?search_query=woodgas+stove&search_type=&search=Search
>
> Regards,
> Rob.
>
> On Feb 12, 2008 10:31 PM, Gerald Van Koeverden <vnkvrdn at yahoo.ca> wrote:
>
> >  As far as quality, you are correct, torrefied wood burns faster than
> > charcoal:
> >
> > "A survey carried out among 180 consumers comparing torrefied wood and
> > charcoal.
> >
> >  Nature, appearance and cleanness were considered to be satisfactory.
> >
> >  Kindling was considered to be easy or very easy, in clear opposition to
> > charcoal kindling.
> >
> >  Glowing embers were considered to form more rapidly
> >
> >  The product appears to be more appropriate to brisk cooking.
> >
> >  Absence of smoke during cooking was noted almost unanimously."
> >
> > http://www.techtp.com/tw%20papers/fao_paper.htm
> > But for those in developing countries who make charcoal strictly for
> > cooking, they would get more energy from the same wood since less is lost in
> > the carbonization process.  90% of the original energy is still in torrefied
> > wood, as opposed to 60% (?) in the charcoal product.   Of course, torrefied
> > wood might require developing a different stove to optimize cooking times.
> >
> > Gerald
> >
> >
> >  On 11-Feb-08, at 11:47 PM, Greg and April wrote:
> >
> >  Grrrrr - one of these days I'll remember to hit 'Reply All'.
> >
> > Anyway -
> >
> >  Doubtful.
> >
> > Part of the lure of charcoal, is a low even heat, with little in the way
> > of smoke ( unless it's on purpose ), if you want a high energy fuel you may
> > as well use propane.
> >
> >  While it may be roasted, I don't think that volatile materials have
> > been fully driven off - just in part ( the lower temperature material ).
> > In the case of specialty hardwoods, like apple or hickory, that's actually a
> > part of what gives the food it's flavor and if a part of it has been driven
> > off, it then the final product is going to suffer.
> >
> > Greg H.
> >
> > ----- Original Message -----
> > *From:* Gerald Van Koeverden <vnkvrdn at yahoo.ca>
> > *To:* Terra Preta <terrapreta at bioenergylists.org>
> > *Sent:* Monday, February 11, 2008 13:09
> > *Subject:* [Terrapreta] torrified wood vs. charcoal
> >
> > *Is torrefied wood going to replace charcoal in our barbecues?  It seems
> > to be both more energy efficient and less polluting...*
> > *
> > *
> > *Gerrit*
> > *
> > *
> > *B: Torrefied Wood, Energy For The Future*
> >
> > At a global level, renewable energy is of increasing importance because
> > of the greenhouse effect. Emissions from the burning of fossil fuels must be
> > reduced, so alternative fuels are needed. Torrefied wood can be burnt in a
> > conventional coal-fired power station.
> > But what is torrefied wood? The word comes from the French 'bois
> > torréfié', which means "roasted wood". This means that the first stage of
> > carbonisation has taken place, without reaching the stage of charcoal.
> > Why pre-treat wood in this way, instead of burning it directly, for
> > example in a bioenergy power station? Thanks to roasting, the fuel is better
> > than ordinary biomass. Torrefied wood is wood that has undergone thermal
> > drying and has a relatively high energy potential (20-22 MJ/kg), and is
> > suitable for grinding in coal-grinding mills. It has an excellent combustion
> > rate and low emissions. Moreover it is easy to store, even outdoors, since
> > it is hydrophobic. Transport is relatively cheap.
> > Initial tests (phase I of the project) were carried out in 2003 in the
> > Netherlands and Britain.
> >
> >
> >
> > Results were very positive.
> > After the positive outcome of phase I, the partners in the project, BGP
> > Ingenieursbureau BV and Stramproy Contracting BV, decided to continue. Phase
> > II is currently in progress. The aim is to produce large quantities of
> > torrefied wood. It is produced in a continuous process plant which can
> > produce a tonne of torrefied wood per hour.
> > Many sectors of industry could be interested in this innovation,
> > especially because of the implementation of the Kyoto Protocol, which allows
> > mixed biofuels to be offset against CO2 emissions.
> > In future, it is believed that production will reach 10 tonnes an hour.
> > In the meantime additional biomass will be provided by agriculture, the food
> > industry, and forestry.
> > Info: H. Kroopman, hkr at bgp.nl - M. Verbeeten, mv at bgp.nl - info at bgp.nl
> >
> > (MilieuDirect, Belgium, www.kluwer.be/kluwer/home.asp?doelid=3)
> >
> >
> > AN FAO paper:
> >
> > http://www.techtp.com/tw%20papers/fao_paper.htm
> >
> >
> >
> >
> > ------------------------------
> >
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> >
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>
>
>
> --
> Robert Flanagan
> Chairman & President
> Hangzhou Sustainable Agricultural Food & Fuel Enterprise Co., Ltd.
>
> Skype "saffechina"
> Tel:   86-571-881-850-67
> Cell:  86-130-189-959-57
>
>
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-- 
Robert Flanagan
Chairman & President
Hangzhou Sustainable Agricultural Food & Fuel Enterprise Co., Ltd.

Skype "saffechina"
Tel: 86-571-881-850-67
Cell: 86-130-189-959-57
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