[Terrapreta] Net Present Value and Net Future Value ofTPBenefits

[Sean K. Barry]

Hi Greg,

What I know of gasification and pyrolysis I basically have learned from reading Thomas Reed's work.  He is from the Biomass Energy Foundation (see http://woodgas.com<http://woodgas.com/>).

In one of the many books of his, "Fundamentals, Development, and Scaleup of the Air-Oxygen Stratified Downdraft Gasifier" it states fairly clearly what the "dry gas analysis of the components in "producer gas" emissions from an "air-blown" pyrolysis reaction made with a biomass fuel are;

~15-25% CO, ~15-20% CO2, ~10-20% H2, ~1-4% CH4, ~40-55% N2

If you are interested, you can buy his books too at the BEF press.

Methane-CH4 has a green house warming potential anywhere from 62 times that of CO2 (in the first 10 years) to an average of 23 times that of CO2 (over a 100 year period).  Is is reactive in the atmosphere, not highly reactive and it does not "dissappear" in 10 years.  It has a half-life of about 10-12 years.

I do advocate the production of very, very large amounts of charcoal for use in soils.  But, I know that this must be done as cleanly as possible.  The pyrolysis reaction which is where and how charcoal is made, DOES PRODUCE METHANE-CH4.  There is no doubt about this.
Just because CH4 is a product gas from a pyrolysis reaction does not mean we cannot use these kinds of reactions to make charcoal or that it would be released from a pyrolysis reactor/gasifier/charcoal kiln/ charcoal retort into the atmosphere.

In short, methane is small potatoes when compared with the amount of CO2 released when we make char - 

You say this and you are wrong about it.  At only 23 times more potent than CO2 (forgetting even the 62 times more potent in the first 10 years) the GHG warming potential of small amounts (~1-4% CH4) of Methane-CH4 has a greater effect than all of the CO2 THAT COULD BE RELEASED!  This is true even if 50-60% of all of the original carbon from the biomass was not retained as charcoal but was released as CO2.  The effect on the atmosphere from ~4% Methane-CH4 would still be worse than that if all of rest of the carbon was released as CO2.

Don't get me wrong.  I say we need to make charcoal as fast as we can and put it into soil.  I don't think we need to let this CH4 emissions issue stop this.  I do think that CH4 emissions from a pyrolysis-for-charcoal reactor do need to be seriously controlled and/or dealt with.


Regards,

SKB

  ----- Original Message ----- 
  From: Greg and April<mailto:gregandapril at earthlink.net> 
  To: Undisclosed-recipients:<mailto:Undisclosed-recipients:> 
  Cc: terrapreta at bioenergylists.org<mailto:terrapreta at bioenergylists.org> 
  Sent: Monday, March 24, 2008 11:11 AM
  Subject: Re: [Terrapreta] Net Present Value and Net Future Value ofTPBenefits


  Sean,

  You keep talking how methane from making TP is so bad, that we may as well not make the char, I now feel that I have ask you to now show documention that backs up your words.


  Sure methane is a more powerful GHG, but it is so reactive that once in the atmosphere, it starts breaking down, and is gone inside of 10 yrs.


  OTOH, any char that is produced is here for hundreds if not thousands of years.

  In short, any negitive effects of methane are out weighed by the positive effects of char, by over 1000 to 1 ( years ).


  Don't get me wrong, I'm not saying that we should just go ahead and make char with nilly willy regard for the end results, because if methane is being produced, then the method used is in effecent because that methane can be rerouted back to be burnt to make the char - thus saving on the fuel needed to make TP in the first place.

  What I am saying is that we shouldn't get so wrapped up in not releasing methane that we never get started in making TP to begine with.

  In short, methane is small potatoes when compared with the amount of CO2 released when we make char - but we know that the CO2 is carbon neutral, what you are appearing to forget is that the methane is also carbon neutral, and also comes back as more biomass.


  To be perfectly honest, I would actually like to know how to produce a liquid that is useable in a diesel engine from the process of making TP - at least then I can power the equipment used to collect and process the biomass, making it ready to turn into TP.


  Greg H.
  _______________________________________________
  Terrapreta mailing list
  Terrapreta at bioenergylists.org
  http://tech.groups.yahoo.com/group/biochar/
  http://terrapreta.bioenergylists.org
  http://info.bioenergylists.org
-------------- next part --------------
An HTML attachment was scrubbed...
URL: /attachments/20080325/4d66bd3b/attachment.html 
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: image/jpeg
Size: 1458 bytes
Desc: not available
Url : /attachments/20080325/4d66bd3b/attachment.jpe