[Gasification] Charcoal Gasifiers

Sun May 8 17:30:53 CDT 2011

Respected TOM

 Like Africa Brazil ,and Thailand also has large numerber of  small scale
charcoal production units .The optimization  of not only the combustion
after burner, comgasifbined  gasification and  Pyrolysis reactors , as well
as  the co2  reuseand reducion  all these need system optimization
studies.Then only the energy recovery and co2 produced during combustion can
be consumed correctly .The best fuel can be the pyrogas that can be turned
into hydrogen rich methane , thus the syngas  can be fed into pyrolysis ,
the energy recoverd  as steam which can improve the quality of both syngas
and  also pyrogas.Several good small sytem are operating well in the case as
isolated system

The choice of correct type of  simple gasifier can make the biomass refinery
plant more flexible.The producer gas can enrich pyrolysis gas , make
possible charcoal and bio char co production , one fourth  of the bio oil
can be easily extracted into useful as much useful bio-diesel.The swirl
type combustion can burn tar char all dirty  of  the kiln exit emission gas
, thus minimiz environmental problems make possible energy
efficiency.However simple equipment design are needed as  the man power
training  of complex technology  need to be considered.Adam charcoal
production made in Pondicherry ,India using after burner make
good energy recovery.Some African rural charcoal kilns do recover bio oil
 with air cooling , thus diluting the pollution problems .Thus using this in
the burner , latter some co2 recycling can be mad possible for charcoal
updraft gasifier.Thus integrated  combustion , gasification , pyrolysis  can
help to solve the challenging problem of charcoal , small energy production
with less co2 problems too, but need collaborative  expert knowledge.

Pannirselvam P.V
Brazil

On Sun, May 8, 2011 at 6:32 PM, Tom Miles <tmiles at trmiles.com> wrote:

> Thanks for the comments.
>
>
>
> Everything counts because outside of India there are probably only a few
> hundred gasifiers generating power. How many of those work 4000-6000 hours
> per year? Very few I would think.
>
>
>
> The context is Subsaharan Africa (SSA) where charcoal is the primary
> cooking fuel, and Southern Africa where abundant biomass exists that is
> underutilized. One project in The DRC promotes fuel wood plantations for
> charcoal. The villages where charcoal is produced are not electrified ad
> will not likely be electrified in the future. Where there is off-grid power
> from gensets it is expensive. So the challenge is how to recover power from
> waste charcoal kiln gases.
>
>
>
> In most charcoal production the kilns are vented as they go through drying,
> torrefaction, pyrolysis and cooling. During drying and torrefaction the
> offgas is mostly CO2 with some CO. The calorific value of the gas is quite
> low (<5 MJ/m3) for the first thirty to forty hours until kiln temperatures
> reach about 280 C. Combustible gases do evolve which should be incinerated
> in an afterburner. From 35-80 hours, a period of about 45 hours, gases
> evolve with a calorific value of about 16 MJ/m3, depending on the peak
> temperature (at 325-380C, 19 MJ/m3 at 500C). During that time the chemical
> energy in the gas is considered to be recoverable. The gas of course
> contains tars and acids. The challenge is how to recover this energy for
> heat or local power generation.
>
>
>
> In the US charcoal kilns are required to use afterburners to burn out the
> gas and pollutants. Solid fuel (e.g. sawdust) afterburners have been largely
> unsuccessful. Most kilns use propane piloted burners that consist of an
> eductor which draws the gases from several (usually four) kilns. The
> standing propane flame ignites the mixture to insure combustion at 1600F as
> required by the EPA. (The most recent batch kiln was installed with a
> catalytic afterburner followed by a lime scrubber and a baghouse.) In
> Brazil, where some large charcoal producers are supplied entirely by
> plantations, companies have studied the evolution of gases and the potential
> for energy recovery. They have tested arrangements of six or more kilns to
> obtain a steady gas flow in overlapping kiln cycles. Some kilns have
> afterburners or combustors. As yet there are no commercial systems
> recovering heat and power from kilns.
>
>
>
> I am inspired by a local biochar producer who uses a downdraft wood fired
> gasifier to heat his batch pyrolyzer. He starts the heating process with
> wood gas. Once combustible gas appears from pyrolysis he valves it into the
> combustor where the evolving gas combines with the flame from the producer
> gas to heat the carbonizer. The wood gasifier provides a stable source of
> heat and ignition. The combustor is the afterburner for the kiln gas. He
> uses a chipper to prepare the wood for the gasifier and pyrolyzer. Chips,
> nuts and shells make great fuels for downdraft gasifiers. If you don’t have
> a chipper (making gasifier fuel by hand is tedious) but you do make
> charcoal, why not use charcoal as the pilot fuel?
>
>
>
> So my thought is to use charcoal from the kiln production to run a small
> gasifier. No need to chip the wood. The gas could be used two ways: A) the
> gas could be used as a pilot for an afterburner which could provide heat to
> dry the fuel to be charred; and B)  cold clean gas could be used to power a
> genset in dual fuel or 100% producer gas mode. A charcoal gasifier requires
> steam which could be supplied from the kiln gas during the early cycle.
> Introduce the kiln gas with the air to the charcoal gasifier. Thus the kiln
> gas could fuel the charcoal gasifier reducing the fuel required to fired the
> engine-genset. You could generate 50 kWe from about six small (12 m3) kilns.
>
>
>
> While a downdraft gasifier might work, an updraft or crossdraft gasifier
> might be more appropriate to this application because of the amount of fines
> generated in the kiln.  A Missouri kiln makes about 23 tons of charcoal and
> 7 tons of fines from 100 tons of wood. In Brazil the fines are spread on the
> plantations (what else in the land of terra preta)? They could also be used
> to fuel an updraft gasifier if fired together with coarser charcoal.
>
>
>
> Putting a gasifier(s) together with a charcoal kiln might be a useful
> “marriage of convenience.”
>
>
>
> Tom
>
>
>
>
>
>
>
> *From:* gasification-bounces at lists.bioenergylists.org [mailto:
> gasification-bounces at lists.bioenergylists.org] *On Behalf Of *Robert Kana
> *Sent:* Sunday, May 08, 2011 10:08 AM
> *To:* gasification at lists.bioenergylists.org
>
> *Subject:* Re: [Gasification] Charcoal Gasifiers
>
>
>
> Dear Tom,
>
> We have tried using charcoal for engine quality gas in 2 types of
> gasifiers. One was our own design, downdraft with tuyers and throat, the
> other design was also downdraft grateless design. At first we had some
> clingers problems, later fixed with adjusting air volume. Gas comes out
> pretty clean. We washed for cooling gas, in a venturi type washer, used wood
> chips/sawdust/charcoal for filter medium. Charcoal used was kemiri (some
> type of nuts grow in Indonesia) shells, coconut shells, regular wooden
> charcoal pieces and briquette charcoal pieces.
> The result was OK. Because charcoal cost here is more, we stopped with the
> charcoal gasification, now concentrating on rice husk and wood chips.
> Any other details you need to know, we will try to answer.
> Actually I have almost 30 tons of charcoal pieces in stock, we were
> originally thinking to built gasifier for use in our own generator. But the
> charcoal pieces we can sell for $ 300.00 for ton. Rice husk here cost $
> 39.00 a ton and we get almost as clean gas from rice husk as charcoal.
> Robert
>
>
> _______________________________________________
> Gasification mailing list
>
> to Send a Message to the list, use the email address
> Gasification at bioenergylists.org
>
> to UNSUBSCRIBE or Change your List Settings use the web page
>
> http://lists.bioenergylists.org/mailman/listinfo/gasification_lists.bioenergylists.org
>
> for more Gasifiers,  News and Information see our web site:
> http://gasifiers.bioenergylists.org/
>
>

-- 
************************************************
P.V.PANNIRSELVAM
ASSOCIATE . PROF.
Research Group ,GPEC, Coordinator
Computer aided  Cost engineering

DEQ – Departamento de Engenharia Química
CT – Centro de Tecnologia / UFRN, Lagoa Nova – Natal/RN
Campus Universitário. CEP: 59.072-970
North East,Brazil
*******************************************
https://sites.google.com/a/biomassa.eq.ufrn.br/sites/
 and
http://ecosyseng.wetpaint.com/

Fone ;Office
84 3215-3769 ,  Ramal 210
Home : 84 3217-1557

Mobile :558488145083

Email:
pvpa at msn.com
panruti2002 at yahoo.com
pannirbr at gmail.com
pvpa at msn.com
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.bioenergylists.org/pipermail/gasification_lists.bioenergylists.org/attachments/20110508/10c7d697/attachment.html>