[Terrapreta] Flaring the more potent GHG in the off gas from acharcoal kiln?

[Sean K. Barry]

Hi Code,

----- Original Message ----- 
  From: code suidae<mailto:codesuidae at gmail.com> 
  To: terrapreta at bioenergylists.org<mailto:terrapreta at bioenergylists.org> 
  Sent: Monday, June 04, 2007 5:26 PM
  Subject: Re: [Terrapreta] Flaring the more potent GHG in the off gas from acharcoal kiln?
> I cannot imagine a large commercial charcoal production operation would not take advantage of the energy
> available in the flare gases. Rather than waste this energy it could be used, for example, in ethanol or
> biodiesel production, thereby offsetting the use of fossil fuels that would have otherwise been used for this
> purpose. 

I agree.  Utilizing the energy outputs from carbonization of biomass, be they heat alone, or heat and energetic gases, should probably be done.  This energy could be used in the charcoal production and/or transportation.
Possible revenues could be earned from sale of the energy in excess of what is needed to operate the plant.
Combined heat and power could easily be provided when making charcoal.

I heat my house with a wood burning boiler, which sits outside my house about 100 feet.  The heat is transferred to the house through liquid heat transfer plate, which passes only heat from the outside boiler water (50 % antifreeze) into the return water line for the inside boiler.  When my "gasifier/pyrolysis reactor/charcoal mill runs, I have every intention to "heat my home", and burn the gas to generate electric power.

But, I am an engineer.  I can design it, weld it, and build the device to do all of this.  I can afford the capital to buy/build it.  My device, so far, is inexpensive, and not highly automated.  Not anyone could use it or operate it without some training.  It will initially be very labor intensive to operate it.

There are some people who could only make the charcoal.  They may not have the abilities or the capital to afford or use a device that does more than make charcoal.  They may only be interested in the charcoal because they want to make Terra Preta.  Whatever type of simple "charcoal kiln" these people are using, there should be a provision in the design to burn "flare off" the methane, because it is better to burn it, than just not use it.

If the methane (CH4) is not used, then "flaring" so important, because if it is not used or "flared", then the deleterious effects to the atmosphere of releasing even small amounts of methane (CH4), would completely outweigh the beneficial effects of burying the charcoal to sequester the carbon.  It even worse for the atmosphere, than burning up (combusting completely) all of the biomass and releasing all of the carbon in it as CO2 directly into the atmosphere.

> I think it could also be argued that since the end product of the process is intended to increase the 
> productivity of the soil one would have to factor in the temporary but long term increase in biomass carried 
> by the soil produced with the char. That is, the increase in biomass that results from soil improvement 
> represents sequestered carbon and should be included in the accounting. 
> 
> Likewise, If char-improved soil were in service as commercial farmland the increased productivity may result > in reduced consumption of fossil fuel based fertilizer and the GHGs that would otherwise have been produced. > These offsets are a direct result of the production of the char and so should also be considered. 
> 
> These factors are difficult to calculate but it seems to me that if the primary goal is sustainability than it is a > bit perverse to only consider the immediate first-order impacts of production.

I basically agree with what you say.  I wonder however if the immediate 62 fold impact (vs CO2) of methane (CH4), which lasts 20 years, and the 23 fold impact, which lasts until 100 years will cause more short term damage than could be had in these other benefits, over the short term.  So you see why I am concerned about it?

As for the accounting of the actual value of a carbon sink?  Here is an idea I dreamt up last night and today about this.  Bank and loan institutions use principle values, terms, and interest rates to keep track of the "future value of money".  The "fixed carbon"  in charcoal and the "soil organic carbon" (SOC) in soil organic matter stores (sinks, banks), also has principle (or measurable) amounts of each.  These decay and grow at various rates (like deposit, loan, or bond interest rates), and the "future value" of the carbon sink (bank) can be assessed over any length term, based on the interaction of those various rates.

I think the "World Bank" (for money) could manage the World's "Carbon Bank".  They could ascribe to areas of the planet (land/and ocean) specific values for deposits (charcoal into soil), growth (of biomass), and losses (plant death and/or low photosynthetic productivity).  Bankruptcy would be like pollution or over spending the carbon in too small of an area or too fast, with no investing.  That is just like people who go bankrupt handle there money.  "Neo Terra Preta" land reforming would be like building a "Capital Growth Fund".  The analogies are stunning, actually, and it makes me think "Carbon Trading", with all of the correct accounting needed could already be managed by disciplines, which we already have in the banking industry.


Regards,

SKB
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