[Gasification] why do liquifaction proceses require nitrogen-less synthesis gas?

[Mark & Elena Gallmeier]

Jim,

> does anyone remember that DIY liquifaction scheme i think mother earth
> news had on running woodgas through some copper tubing and getting
> some liquid fuel out?  messy but it worked.  i can't find it after
> much looking.  i'd really like to find it.  anyone know?

This might be the article you want:  http://homepower.com/files/woodgas.pdf

Best Wishes,

Mark

"I see the bad moon arising. I see trouble on the way. ..."


> Message: 4
> Date: Sun, 28 Jan 2007 18:27:54 -0800
> From: "jim mason" <jimmason at whatiamupto.com>
> Subject: Re: [Gasification] why do liquifaction proceses require
> nitrogen-less synthesis gas?
> To: gasification at listserv.repp.org
> Message-ID:
> <31a4f6f00701281827m6f55e154wff46dd91c6246ccb at mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> 
> it must be more than an efficiency issue, or we would see many more
> air blown units operating where efficiency is not reckoned in absolute
> thermodynamic terms.  or maybe not.  can the actual chemists chime in
> here?
> 
> does anyone remember that DIY liquifaction scheme i think mother earth
> news had on running woodgas through some copper tubing and getting
> some liquid fuel out?  messy but it worked.  i can't find it after
> much looking.  i'd really like to find it.  anyone know?
> 
> i'm seeing methanol processes that can work at as low of pressures of
> 150-300psi, and fischer tropsch processes that can work at 0psi, or
> 1atm.  all in the 250c, 400f range.
> 
> most of the methanol processes are highly selective for just methanol
> out.  the FT processes give you a wide range, from alcohols through
> parafins.  in general, as the pressure and temp goes up, the processes
> become more selective for desired outputs.  which is opposite of what
> the DIYer can handle.  but still, a poorly selective process in the
> few hundred psi and temp range seems not unthinkable.  but we do need
> a compressor for most, especially the better processes.
> 
> thinking about compressors we have on a car, i notice that the engine
> itself is a compressor, and that we might add a system of "gasifier
> regenerative braking", by killing the spark and letting the engine
> pull woodgas and pressure it into the liquifaction unit, using the
> braking momentum of the car.  if we need more pressure, run this
> output through the AC pump, for a couple hundred more psi.  AC pumps
> already have nice clutches, so intermittent service is possible.
> 
> another petroleum engineering question.
> 
> if the fischer-tropsch processes output a mixed bag of HCs, usually
> needing a distilling tower to separate off what you want, why can't we
> have a small version of the same onboard, only mining the highest temp
> condensates, which are the fuels we want usually, and then cooling all
> the rest and dumping it back into the gasifier as fuel.  just let all
> the extra stuff fall into the water condensor/cooler slurry, then
> always mine the top of the water, injecting it back into the gasifier
> as "flamable steam".
> 
> sure, we'd loss some heat in the process, but making a little liquid
> fuel would while doing other IC tasks with woodgas would have many
> benefits.  for instance, you make your own starting and acceleration
> fuel.  keep the dual fuel carburetor set up so you can run both
> woodgas and liquid fuels as desired.
> 
> more importantly, such a scheme seems a major component towards the
> often discussed combined heat/power/fuel unit.  to this we should
> really add fertilizer, as the char ash out of a gasifier is great
> fertilizer.
> 
> and if we argue that we are saving a ton of CH4 emissions that would
> have happened had the biomass just rotted into the ground (without the
> oxidation energy mined and used in the process), we can make a sneaky
> argument that thoughtful gasification can actually be a carbon
> NEGATIVE endeavor.  introduce no new carbons through the "burning" of
> biomass, prevent the very bad CH4 greenhouse gas emissions of rotting,
> then sequester a good portion of the originally "in play" carbons as
> benefacted fertilizer, using the massive scale carbon sequestration
> scheme we already have in place, which we call "plow agriculture" . .
> .
> 
> somehow i always knew the hippie composters were evil and it was the
> pyros who would somehow save the world in the end . . . ;-)
> 
> "gasification: burning things to save the world"
> 
> (think we can get al gore to sign on?)
>