[Terrapreta] Char made made under pressurized conditions?

[Sean K. Barry]

Hi Greg,

Dr. Antal would know enough to answer most of your questions , I think.  His process can/does make activated charcoal, with little or no VM.  The reactor has to be run very hot to do this, like 900º C.  Activated charcoal has a very high surface area.  I don't know what this says about the actual pore struture though.  Probably lots of smaller pores.

I think it is a very good idea to mix charcoal with compost or other bio-fertilizers, something to set the C:N ratio more towards 40:1 down to 25:1.  If less charcoal is applied onto a field more often and cultivated in with other to-be-composted biomass, this will do the same thing with less charcoal, I would think.

I like the idea of getting charcoal, usable heat, and liquid transport fuels all entirely from biomass sources.  It should be recognized, though, that even biomass has a finite amount of chemical energy contained within it.  If you want all of this, then you need to have a pyrolysis process that makes the charcoal, allows you to recover and to use the heat directly, and then the fractional liquid distillates and or gaseous fuels will need to be refined and made directly into liquid transport fuels.  This last step of refining the liquids and/or gases to make automotive fuels is very difficult.  It can be done, but it requires expensive catalysts and the economies of a much larger scale.

There is a plant in Iowa, Colorado, and California, Rentech, that makes synthetic diesel fuel from "synthesis gas" (Syngas: mostly, H2, CO, some CO2, very little CH4) that is reformed from coal.  Syngas can be made from biomass, also, by blowing pure oxygen (instead of air) through a pyrolysis reactor.  "Producer gas" is just like syngas that has been diluted with Nitrogen-N2 (it also has more CH4, like ~1-3% content).

There are other possibilities, too.  For instance the heat and fuel gases or vaporized liquid VM can all be burned and used to produce heat and/or bring up steam to turn a turbine and produce electricity.  The fuel gases can run an internal combustion engine that turns a generator, too.
Some cars can be made to run directly off the gases from a charcoal making retort (see "woodgas" cars at www.woodgas.com<http://www.woodgas.com/>).  But, it is hard on ICE and these engines do not last long unless the gas used for fuel is very clean.  It you had an electric car, then the electricity you produced could charge the batteries on your car.

Regards,

SKB




Regards,

SKB
  ----- Original Message ----- 
  From: Greg and April<mailto:gregandapril at earthlink.net> 
  To: Terra Preta<mailto:terrapreta at bioenergylists.org> 
  Sent: Saturday, March 29, 2008 11:50 AM
  Subject: Re: [Terrapreta] Char made made under pressurized conditions?


  Either case, I still doubt that N2 as a reasonably inert gas will do
  anything - either as a fertilizer or be absorbed into the char.    Remember,
  most plants can not make use of gaseous nitrogen - only legumes, and they
  have little need to pull it out of the ground, when they can pull unlimited
  quantities out of the air, faster than we can even make char.   < grin >

  OTOH, nitrogen as a compound - such as ammonia or urine has much greater use
  as a fertilizer, and as something that can be absorbed into the char.


  Personally, I hope to be adding char to the litter that is used for animal
  bedding, thus giving it every chance to absorb any number of useful
  fertilizer compounds, and be inoculated with any number of biological
  organisms.

  But that is actually beyond the question I asked.

  What I was looking at is several possible results wrapped up under the
  heading of " char produced under pressurized conditions ".

  "Does char produced under pressurized conditions have a larger pore
  structure or a smaller pore structure?"    I don't know, but it is quite
  possible that there would be some change ( I would be surprised if there was
  not some physical change - although perhaps not that we would immediately
  recognize.    Are the changes good or bad?     I have no idea.    That's why
  I'm asking.


  "Are the distillates produced under such conditions, more readily useable as
  a liquid fuel?"    There is some indication that this is true, as there are
  a number of patents based not only on dry thermal depolymerization, but wet
  thermal depolymerization as well, with temperatures starting as low as 250*C
  or so ( usually with much higher pressures than 100 psi ) - but it's also
  been known to happen at higher temperatures and lower pressures.
  Wouldn't you agree that in a world with increasingly higher liquid fuel
  prices, it would be really nice to be able to heat your house, make some
  Terra Preta and a tank of fuel at the same time?    Again, this is why I'm
  asking.


  Greg H.

  ----- Original Message ----- 
  From: "Jeff Davis" <jeff0124 at velocity.net<mailto:jeff0124 at velocity.net>>
  To: "Terra Preta" <terrapreta at bioenergylists.org<mailto:terrapreta at bioenergylists.org>>
  Sent: Friday, March 28, 2008 21:38
  Subject: Re: [Terrapreta] Char made made under pressurized conditions?


  > Hi Greg,
  >
  > I just happen to have that book with me. They explain the four stages of
  > charcoal production, the third being the "exothermic period" and that is
  > about 400 C. The fourth stage called the "cooling period" comes next but
  > they do not state any temperture range. Maybe the cooling period is 400 C
  > to safe handling temperature. I honestly do not know.
  >
  > I was just wondering if there could be somekind of opportunity for us at
  > this stage of charcoal production. Maybe nothing to do with
  > nitrogen/ammonia etc but something else.
  >
  >
  >
  > Kindest regards,
  >
  >
  > Jeff
  >
  >
  >
  >> Hmmm........
  >>
  >> Correct me if I'm wrong, but is it not true that char can still be quite
  >> warm, and not burn when O2 comes in contact with it?
  >>
  >> It is with that in mind that I asked what I did in my previous post -
  >> after
  >> all, you didn't exactly say at what temp the char was cooling from did
  >> you?
  >>
  >> No offense,
  >> Greg H.
  >
  >
  > -- 
  > Jeff Davis
  >
  > Some where 20 miles south of Lake Erie, USA
  >
  > _______________________________________________
  > Terrapreta mailing list
  > Terrapreta at bioenergylists.org<mailto:Terrapreta at bioenergylists.org>
  > http://tech.groups.yahoo.com/group/biochar/<http://tech.groups.yahoo.com/group/biochar/>
  > http://terrapreta.bioenergylists.org<http://terrapreta.bioenergylists.org/>
  > http://info.bioenergylists.org<http://info.bioenergylists.org/> 


  _______________________________________________
  Terrapreta mailing list
  Terrapreta at bioenergylists.org<mailto:Terrapreta at bioenergylists.org>
  http://tech.groups.yahoo.com/group/biochar/<http://tech.groups.yahoo.com/group/biochar/>
  http://terrapreta.bioenergylists.org<http://terrapreta.bioenergylists.org/>
  http://info.bioenergylists.org<http://info.bioenergylists.org/>

-------------- next part --------------
An HTML attachment was scrubbed...
URL: /attachments/20080329/e8bde767/attachment.html