[Terrapreta] Charcoal properties

[Sean K. Barry]

Hi Michael,

I believe the HEAT is valuable.  Either the excess heat from the carbonization process itself or the afterburning of the off gas could be useful.  How about heating steam to drive a turbine, maybe a Tesla turbine to generate electricity.  I think the carbon sink idea behind sequestering charcoal in soil is a fine and laudable idea, ecologically, with global warming and all, etc.  But, it needs a few things, I think, to really be a go;

1) There really needs to be an proven advantage in to putting it into agricultural soil.  The ancient Brazilian natives may have been adherents and believers, but American farmers are a very conservative bunch, almost arrogant in their belief that they now how to produce more food off the land than any other culture in history (which is fairly well true) and they are going to be hard to convince to change their practices.  You can do all the research you want in Brazil, Sumatra, Japan, and even Hawaii, but American farmers are going to want American soil scientists doing it on good old American mainland soil for a long time before they are going to be willing to change what they are doing.  Just look at the problems of getting no-till or even low-till farming practices in place (which is also a great idea for carbon sequestration, i.e. reduce soil disturbance and increase soil organic carbon).

2) There should be an immediate economic incentive to making charcoal and putting it into the ground.  You said it yourself, it is a valuable fuel, it has uses in barbeques, medicine, metallurgy, etc.  How can selling charcoal to be put into the ground hope to compete against using it as a fuel in an energy addicted world?  Only 60% of the energy from biomass remains in the charcoal with even the most energy efficient way of converting biomass to charcoal (Flash-carbonization).  If even part of the other 40% could be captured and put to work directly, making electricity, or providing a raw material (synthesis/producer gas) to make liquid fuels, then charcoal manufacturing could make money on carbon neutral energy production right away, maybe even be profitable, and then also make great strides towards a working carbon negative technology.

3) This whole charcoal from biomass thing has got to be distributed.  The source for the biomass is already distributed, out on the land, under the sunshine, growing.  The target areas where the charcoal is to be distributed are back out over the land. Your device, which can make charcoal from nearly any biomass, with nearly any moisture content (<50%), is small enough to be almost portable and productive enough to keep up with as much waste biomass as maybe, a 1/2 section field could produce in a year.  Trucking raw biomass to charcoal production factories and trucking the charcoal back to the same fields that the biomass came from just seems like a waste of energy to me.  Transport energy, too, which nowadays is still mostly fossil fuel based.  To be most effective as a valuable carbon sink, putting charcoal into the soil is going to have to put a lot of charcoal into a lot of soil, distributed over huge areas.  It is also likely going to have to go on and on for years, before a dent can be made.  We don't grow enough waste biomass over the entire area we grow crops in to produce enough charcoal to bury in a big enough area to solve the problem in a year.  It's not going to be a one time, two way, shipping deal.  Humankind puts 6 giga-tons of fossil fuel based carbon into the atmosphere every year, now.  That number is growing fast.  Charcoal production and sequestration needs to beat that number down with offsets.  I believe it will be done much faster if we don't waste more fossil fuel doing it.

Harvesting renewable energy and producing carbon offsets by charcoal sequestration in soil are by their very nature, DISTRIBUTED endeavors!

... and then,  Sean stops his rant, steps of his soapbox, and bows slightly.

Regards,

SKB

Sean K. Barry
Principal Engineer/Owner
Troposphere Energy, LLC
11170 142nd St. N.
Stillwater, MN 55082
(651) 351-0711 (Home/Fax)
(651) 285-0904 (Cell)
sean.barry at juno.com<mailto:sean.barry at juno.com>
  ----- Original Message ----- 
  From: Michael J. Antal, Jr.<mailto:mantal at hawaii.edu> 
  To: Sean K. Barry<mailto:sean.barry at juno.com> 
  Sent: Thursday, March 08, 2007 12:37 PM
  Subject: RE: [Terrapreta] Charcoal properties


  Hi Sean: your conclusion is correct; you can't have a high yield of carbon and a high yield of gas at the same time.  In the long run people will realize that the carbon is much more valuable than the gas (or the tar).  This is why we have emphasized carbon yield.  On the other hand, our gas is not as bad as you seem to think.  It burns well in the catalytic afterburner.  We have generated temperatures in excess of 1500 C in the afterburner on some occasions.  Heat at 1500 C has lots of uses.  Thanks, Michael.
    -----Original Message-----
    From: Sean K. Barry [mailto:sean.barry at juno.com]
    Sent: Wednesday, March 07, 2007 7:54 PM
    To: Michael J. Antal, Jr.
    Subject: Re: [Terrapreta] Charcoal properties


    Hi Michael,

    That was a tough paper.  The composition of the exit gas from the high pressure Flash-carbonization reactor is disconcerting;  "0%-2% hydrogen, 0%-14% oxygen, 60%-80% nitrogen, 0%-10% carbon monoxide, 0%-3% methane, and 2%-20% carbon dioxide".  I'm sure producer gas like that is pretty low BTU gas.  It also contains some trace amount (any idea about the tar ppm?) of unknown particulate matter;

    "... the chemical composition of this unknown compound is similar to that of a carbohydrate (e.g., levoglucosan or hydroxyacetaldehyde). Carbonaceous particulate matter is also a possible explanation for this unknown compound."

    Gas like that could never provide the fuel charge to run any kind of internal combustion engine generator and the particulate matter would clog everything.  Has anybody in your group thought about any way to use the excess heat?

    You say this at the end of the paper,

    "Although the identification of this unknown is not easy in our system, we plan to initiate an evaluation of particulate matter emission from the FC reactor soon."

    It doesn't much matter, I think.  That gas is almost useless as any kind of fuel.  You're doing the best you can with the caalytic afterburner to clean it up a bit before you vent it to the atmosphere (eliminate CO, reduce CH4, etc.).  Did anyone ever think about just using a catalytic converter from off the back of a vehicle to do that job?

    By my asking questions about the exit gas from the FC, I hope you don't think I am missing the point of your work.  The charcoal and fixed carbon yield of that charcoal is an impressive result of the Flash-carbonization reactor design.  That seems to have been your objective.  I'm trying to see if charcoal production for agricultural use and its consequent carbon sequestering, which overall is a carbon negative process, can be made to work with using some of the biomass chemical energy as a carbon-neutral fuel at the same time.

    Biomass-to-charcoal/biomass-to-gas reactors which operate at atmospheric pressures may have lower charcoal yield, but they can be made to produce a gas which has a usable BTU content (~300 BTU/Nm^3).  And, it can be cleaner of tars (~2-15ppm). So, it can be a useful as a fuel for less expensive ICE powered generators.

    This all does make some sense; you can't have both high charcoal yield and high BTU gas coming from a carbonization/gasification
    reaction.  One or the other, because there is only so much chemical energy in the biomass feedstock.  When you raise the charcoal yield and the fixed carbon yield you leave more of the energy in the solid product.  The evidence that your FC process approaches the thermo-chemical equilibrium limit is clearly born out in the low energy content of the gas product.  <--Right?


    Regards,

    SKB

      ----- Original Message ----- 
      From: Michael J. Antal, Jr.<mailto:mantal at hawaii.edu> 
      To: Sean K. Barry<mailto:sean.barry at juno.com> 
      Sent: Wednesday, March 07, 2007 8:15 PM
      Subject: RE: [Terrapreta] Charcoal properties


      Hi Sean: pls see the attached paper.  It should answer your questions.  Regards, Michael.
        -----Original Message-----
        From: Sean K. Barry [mailto:sean.barry at juno.com]
        Sent: Wednesday, March 07, 2007 11:49 AM
        To: Michael J. Antal, Jr.
        Subject: Re: [Terrapreta] Charcoal properties


        Hi Michael,

        Thanks for taking time to review my questions and sending the papers along.  I am still curious why you said you were unable to burn off the producer gas coming from the pressurized (1MPa) laboratory carbonizer/gasifier?  Is the gas too high in CO2 and H2O, and too low in CO and H2?  What is the BTUs for Nm^3 for the off gas?

        SKB
          ----- Original Message ----- 
          From: Michael J. Antal, Jr.<mailto:mantal at hawaii.edu> 
          To: Sean K. Barry<mailto:sean.barry at juno.com> 
          Sent: Wednesday, March 07, 2007 1:51 PM
          Subject: RE: [Terrapreta] Charcoal properties


          Hi Sean: the attached papers answer your questions about elevated pressure effects on charcoal yields, and results when lambda = 0.  The big surprise of our Flash Carbonization research was the high yields of charcoal with increasing lambda (up to a point).  Regards, Michael.  P.S. Your question about posting the ASTM procedure on the website is well posed.  My impression is that the UH/HNEI interpretation of copyright law is more stringent than most.
            -----Original Message-----
            From: Sean K. Barry [mailto:sean.barry at juno.com]
            Sent: Monday, March 05, 2007 8:40 PM
            To: Michael J. Antal, Jr.
            Subject: Re: [Terrapreta] Charcoal properties


            Hi Michael,

            I've finished reading the "Charcoal Review(PyNe).pdf" document.  It doesn't add much to your "Flash_carbonization.pdf" paper, beyond maybe the historical information and the current practices.  My question remains?  Is it the low airflow (~25% of the stoichiometric) or the 1MPa pressure which imparts the higher fC and charcoal yields in the "Flash_carbonization.pdf" process?  Clearly, the high pressure make for the fastest pyrolization method available.  The other industrial processes were taking many hours and even days.

            Do you have papers on, or can you refer me to any experiments comparing high pressure vs atmospheric pressure, both at zero lambda?  Do you have any experiments comparing different lambda (0, low, high) at high and/or atmospheric pressure?

            Now, I've scanned into the "Charcoal Review (iec03).pdf" paper, down to the Effects of the Gas Environment section.  You nearly answer the question ONE WAY down in the first paragraph.  "High pressures are not needed to secure a high yield of carbon from cellulose after equilibrium is established."  <- Do you think so?  Then, a little later in the Pressure. section you answer it THE OTHER WAY.  Figure 6 clearly shows experimental data for improved charcoal yield with increasing pressure and the same low flow (hopefully, low flow equates closely with lambda near ~25%?).  Is improved charcoal yield synonymous with improved fC yield?  Can you get good AgChar out of a "flash carbonization" reactor?

            Well, now you've got me thinking on how to build a higher pressure (1MPa) "flash carbonization" reactor, for fast reaction times and high yield but for less than $100,000.  I'd also like to figure out a way to use the producer gas coming out of the reactor. 

            I paid $30.00 for the "Chemical Analysis of Wood Charcoal" ASTM 1762-84 last night, ordered the .pdf directly from ASTM.  I saw you were sending a copy for Tom Miles to post online.  Like your reasoning for not posting some other papers for not stepping on toes with the ACS group, maybe ASTM won't want you or Tom posting ASTM-1762-84.  <-Do you think so?

            Thanks very much, Michael, or your interested replies to me.

            Best Regards,

            SKB
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