[Terrapreta] products of pyrolysis reactions

[Sean K. Barry]

Hi Michael, Francoise et al,

This surprises me greatly Michael.  I thought you understood that pyrolysis and gasification of biomass occur together?!  Pyrolysis is the thermal decomposition of biomass.  It decomposes into among other things, hot gases, like CO2, CO, H2, H2O, N2, O2, and CH4.  This is gasification of biomass.  The "off-gas" from pyrolysis reactions is usually called "producer gas" when air is used as an oxidant or "syngas" when pure oxygen is used or no oxidant is used (inside sealed retorts).  Any pyrolysis reaction in biomass, be it in a kiln, a pit, a retort, a TLUD, a stratified down-draft gasifier produces some gases.  There is also some part of the biomass which is converted to liquids (tars, bio-oils, vaporized in the heat and entrained with the gas if there is a pressurized draft), some of the biomass carbon is left as CHARCOAL, and then there is mineral ash, too.  The ash component is usually on or in the charcoal itself or mixed in with the liquids.

Many on this list have spoken about "burning" the combustible gas fraction of the producer gas (H2, CO, and CH4 are combustible fuel gases) and using the heat to make the pyrolysis reaction continue in the biomass feedstock.  Pyrolysis reactions start out endothermic, which means they require the continued application of heat in order to continue.  At high enough temperatures the reactions can become exothermic, which means that they will produce enough heat by themselves to continue the reaction without further addition of the heat.

Keep watching.  I think most on the list would agree that production of charcoal from biomass is a necessary requirement to forming Terra Preta soils.  Pyrolysis and gasification of biomass are both going to occur when charcoal is made from biomass, especially if there is any air or oxygen used to make the pyrolysis reaction continue.

Hopefully you do know, too, Michael, that there is a large amount of HEAT liberated from pyrolysis reactions.  I think it is "ON TOPIC" to discuss use of the products from pyrolysis reactions.  In the most efficient of charcoal production processes, 50-60% of the energy contained in the chemical structure of the biomass can be retained in the charcoal (see the work of Dr. Michael J. Antal).  The remaining energy is released predominantly as heat and as chemical energy in the combustible fuel gases (H2, CO, CH4).  The other gas fraction (CO2, H2O, N2, O2, etc) contains no useful chemical energy as it requires the input of more energy to decompose these gases further.  They do carry heat energy though.

Hot smoke contains these complete combustion product gases (CO2 and H2O), entrained vaporized liquids (tars, bio-oils, etc), and blown off bits of carbon from the charcoal (soot, solid particulate matter).

Here is a simple diagram,

BIOMASS FEEDSTOCK => {Pyrolysis reaction} => HEAT + GASES + LIQUIDS + CHARCOAL + ASH

Regards,

SKB
  ----- Original Message ----- 
  From: Michael Bailes<mailto:michaelangelica at gmail.com> 
  To: francoise precy<mailto:f.precy at hotmail.co.uk> ; Terra Preta<mailto:terrapreta at bioenergylists.org> 
  Sent: Sunday, June 01, 2008 2:25 AM
  Subject: Re: [Terrapreta] negative effects of charcoal, no instantaneousness,and





  2008/5/31 francoise precy <f.precy at hotmail.co.uk<mailto:f.precy at hotmail.co.uk>>:


    Wow, visited by archangel,
    hello Michael
    thanks for your mail.

  Yes if you have periods just keep an eye on the date next month :) 


    Gasification:
    After 2 hours of wild meanderings from your email thru all aspects of fire in various dimensions, you somehow got me to pair these two: gasification – pyrolysation, and suddenly realize that these are so to speak "the two faces of the charring process". Following Sean got me to yo-yo between the two without seeing the link. A whole new set of horizons. Thanks very much.

    why charcoal sometimes brings negative results:
    ... b/c they weren't doing "charcoal soul amendments" - and in a space capsule :-) couldn't be sweeter.
    Was writing 2 days ago: "D'you know, I got a feeling that in that particular case precisely (of negative results) the key-word in the primary term of the equation "charcoal + biomass = TP", wouldn't be the charcoal but the biomass."

    Besides that, it's been my shameful regret to face the fact that I did not check what had been going on in the list re. these articles.

  It was a good discussion you should chase it up. 


    Promise no more bricks til this one's been well forgotten.
  bricks
  TP is not a religion (YET Erich and I are working on it) so we need to look at the science.
  The problem is it is so complex and involves so many scientific disciplines.
  I FEEL that in the end it is going to come down to the "wee beasties" and 'critters' in the soil. Problem is  they are slippery little buggers and  studying them is fraught with all sorts of technical and scientific problems. We have probably only named less that 30% of them. Talk about "Bulls in a China Shop" these are the guys that keep us fed after all and we know pitifully little about them
  At least TP focuses on them (WBs and Critters) and soil is not just seen as a hydroponic medium to make plants stand up wile we supply all their needs and spray all their "enemies".


  m 


    _________________________________________________________________

    http://clk.atdmt.com/UKM/go/msnnkmgl0010000009ukm/direct/01/<http://clk.atdmt.com/UKM/go/msnnkmgl0010000009ukm/direct/01/>



  -- 
  Michael the Archangel
  "Politicians will never solve The Problem;
  because they don't realise they are The Problem.".
  -Robert ( Bob ) Parsons 1995
  _______________________________________________
  Terrapreta mailing list
  Terrapreta at bioenergylists.org
  http://tech.groups.yahoo.com/group/biochar/
  http://terrapreta.bioenergylists.org
  http://info.bioenergylists.org
____________________________________________________________
Need cash? Click to get a loan.
http://thirdpartyoffers.juno.com/TGL2141/fc/Ioyw6i3mKiwN6uHKEFOsUno1xHLNZoGBoe4UkflV3EnJaIoII8fLyI/
-------------- next part --------------
An HTML attachment was scrubbed...
URL: /attachments/20080601/9c757ae2/attachment.html