Skip to Content.
Sympa Menu

permaculture - Re: [permaculture] Any idea is this is viable?

permaculture@lists.ibiblio.org

Subject: permaculture

List archive

Chronological Thread  
  • From: "Kelly Finigan" <kfinigan@spots.ca>
  • To: permaculture <permaculture@lists.ibiblio.org>
  • Subject: Re: [permaculture] Any idea is this is viable?
  • Date: Tue, 19 Aug 2003 12:12:01 -0700

Hi Michelle:

start with a quick definition of pyrolysis from
http://www.wgtuk.com/ukDefinitionPyr.html

"Pyrolysis uses indirect heat to convert solid organic materials, into gases
and liquids. Conversion is carried out in a reaction chamber where air
(oxygen) is excluded. The material within the reaction chamber is heated to
temperatures of between 400 - 800°C; usually by combusting a portion of the
gaseous or liquid products. The resultant products of the pyrolysis process
always include gas, liquid and solid char. Operating conditions and reactor
design can be selected to control the relative proportions produced from the
process.

slow pyrolysis - a slow reaction carried out at low temperatures producing a
high yield of solid char.

fast pyrolysis - a reaction used to maximise either gas or liquid products.
The liquid (or oil) phase is a complex mixture of hydrocarbons and requires
further treatment before being used as a fuel.

The gases produced from pyrolysis have a higher CV then those produced from
gasification as there is no dilution by nitrogen or flue gases. The CV of
the gas can range from 15 - 30 MJ/Nm3."

Your question: "is this viable?"

my answer (others may vary...): it depends on the definition of "viable",
the source feedstock, and the end use.
if viable means "can we physically do this"...answer is yes
if "viable" means "do we get more useful energy out of the process" or "is
this part of a sustainable future society?"...it depends

we must consider the full energy cycle of the system, from feedstock to end
use. This is influenced by many variables:
1 how are we producing the heat for the pyrolysis - natural gas? solar?
2 where is the feedstock - sawmill in remote northern Saskatchewan or Quebec
or a waste wood stream near a large city...
3 what is the end use - driving a sole-occupant vehicle for a relatively
mindless trip, powering earthmoving equipment to make a storage dam, or
running equipment to assemble a wind mill/turbine (i.e. something that uses
more energy or generates more energy)

without performing the whole energy cycle calculations, my "gut" feel
(having performed / reviewed lots of energy & material cycle studies)
is that in most cases, the pyrolysis system will be a net energy loss...this
incidentally is the same for MOST ethanol systems (relying on heavy fossil-
based fertiliser inputs, fossil energy for processing and long transport
distances to markets/end use).

HOWEVER, if performed sanely, (possible examples: fuel creation from "waste"
at sawmills to provide fuel for forestry operations and for nearby
communities, or to transform "waste" in urban areas into fuel) pyrolysis MAY
be suitable in some places.....then again, it may be better to use
the "waste" wood as mulch and return it to the forest / urban landscape...an
energy cycle study would indicate the best use.


hope this helps rather than confuses you,

ciao,
Kelly










On Tue, 19 Aug 2003 12:03:52 -0400, Michele May wrote
> Pyrolysis Oils from Biomass
> Producing, Analyzing, and Upgrading
> Edited by ED J. SOLTES, Texas A&M University, and THOMAS A. MILNE, Solar
> Energy Research Institute
>
> Brings together specialists to present the state-of-the-science in
> the complete fuel cycle--from feedstock to upgraded liquid fuels suitable
> for replacements for petroleum-derived fuels. Offers a discussion of
> biomass pyrolysis and its place in the renewable fuel economy. Presents
> the technology of pyrolysis oil production. Describes analysis of the
> oils by characterization, kinetics, and chromatographic techniques.
> Concludes with a discussion of upgrading pyrolysis oils to liquid fuels.
>
> _____
>
> 368 pp.; 128 linecuts; 0-8412-1536-7
>
>
>
> http://www.hempcar.org/petvshemp.shtml



--
Kelly Finigan, M.Sc. P.Eng. Permaculture Designer
~ Sustainability consultant & ecological designer ~

744 - 4 Street NW
Calgary, Alberta T2N 1P2
phone 1-403-283-7270





Archive powered by MHonArc 2.6.24.

Top of Page