[Bioconversion] Carbon Arc Steam Reforming of biomass

[AJH]

On Sat, 23 Jun 2007 16:21:25 -0400, Dick Glick wrote:

>That's right and during WWII -- Germany ran on slave labor

Irrelevant


>-- and the 
>environment be damned 

Fair comment, we now know that we must take environmental damage
seriously. Now we are considering *only* biomass feedstock, the
harvesting of which can have a small environmental footprint.

This proposition is also that the syngas is free of tars and doesn't
then require cleaning, even though this is unlikely a modern approach
will contain any contaminated outputs.

>-- And -- the conditions may be slightly different --  
>but the environment and the labor issues differ -- but only slightly in 
>South Africa -- I'll be glad to send all that stuff on how the National 
>Academy of Science evaluated the degraded U. S. supply of coal -- but that 
>stuff is in the news -- last week in the New York Times.

If anyone wants it then send it by personal e-mail, there's little
point in flooding this list with long quotes that many will not read.
If anyone wants to gather info from this article and summarise how it
may be applicable to bioconversion then feel free.

>From: <tombreed at comcast.net>
>To: "Discussion of biological conversion to fuels and chemicals" 
><bioconversion at listserv.repp.org>; "Discussion of biological conversion to 
>fuels and chemicals" <bioconversion at listserv.repp.org>
>Sent: Saturday, June 23, 2007 3:31 PM
>Subject: Re: [Bioconversion] Carbon Arc Steam Reforming of biomass

>>
>> So we know a lot about high temperature processes that have worked in the 
>> past and now need to be modernized.

Yup, I think the discussion sits as well here as on [gasification]

To keep it simple the proposition is that biomass, and I'll use a
simple molecule of cellos, can be directly turned into syngas, CO and
H2 by providing the necessary energy to heat it up and break bonds
with an electric arc.

C6H10O5.H2O + spark =>  6CO + 6H2 + waste heat

lhv 16.4MJ*0.18kg    => 9.05*0.168kg + hhv 117.83MJ*0.12kg

2.952MJ/mol             1.5204MJ/6mol +  14.1396MJ/6mol

This neglects the sensible heat in the output

Are my calculations correct?


Daniel Chisolm ran the calculation though some gasifier software on
[gasification] and came to a similar conclusion, the arc must input
more energy than that the biomass provides, so the biomass only really
provides a carrier for the electrical energy. Electrical energy is
more useful than the thermal energy in the syngas.

Can we retrieve anything from this?

Daniel Nicoson proposed running the arc in parallel with conventional
gasification and using its extra energy to clean tars, principally I
guess by pushing up the temperature of the offgas leaving the
reduction zone from about 850C to ?...

I speculated the need to keep massflow down and feedback heat from a
genset but the step from 850C up would have to be supplied internally
as non of the external streams are this hot, so the only inputs are
from cooling the syngas and the arc.

If this syngas is to remain cool it must be rapidly quenched. This
suggests it will need to run at pressure (bad for the mass action as
it favours soot formation) and then rapidly expanded, doing work. This
makes it less able to deliver high temperature back to the reagents.

Anyone care to comment?

AJH