[Gasification] Cellulosic ethanol: an alternative route...

[Zietsman, Rex]

Brian Hans wrote:
"I think i would hate the future landscape of an energy starved world
trying to pathedically, inefficiently power itself using (cellulosic)
ethanol. i feel the green movement is about to be trampled over by the
herd of hungry cows in search of booze...
i like the research part, i hate the 'shootfirst and ask ?'s later'
part. im thirsty and hungry just thinking about ethanol in my SUV."

Roger Samson wrote:
"Brian you are correct, cellulosic ethanol from grass is not energy
efficient. You only recover about 39% of the original energy stored in
the switchgrass in the field as ethanol and electricity. It would be
better to make fuel pellets (recover 95%) for direct heating
applications or use it as an energy feedstock to produce biogas and
thermal heat like the Germans are doing so successfully. The US seems to
be obsessed about making liquid fuels, however it is poor energy
security policy, poor environmental policy and harmful to the American
taxpayer relative to other bioenergy options." 
 
Rex writes:
As my premise, I am suggesting that the main reason for producing
ethanol is to produce a renewable liquid fuel that will power existing
combustion engine vehicles.
We all realise that converting cellulose to ethanol is challenging:
while the feedstock may be relatively cheap (stover vs corn for
example), the cost of cellulose conversion at present using acid
hydrolysis followed by enzymatic attack (plus any and all the variations
you can think of including steam explosion, peroxide pre-treatment, high
temperature weak acid hydrolysis, low temperature strong acid
hydrolysis, and..., and...) makes the overall process expensive. Then
there is the issue of the lignin which generally defies attack and
refuses to come to the party...
One company that has overcome this problem is BRI Energy:
http://www.brienergy.com/ BRI has a technique of fermenting gasifier
syngas to ethanol. Over the past six or so years, they have developed
the systems where their bug has the ability to convert syngas CO and H2
into ethanol in a matter of minutes. The major benefit of this is that,
unlike acid hydrolysis and conventional fermentation, lignin is included
in the recovery. The second major benefit is that "any" syngas (I
suspect there are some poisons in some of the gas sources that could
harm the process though biogas syngas apparently works) can be used.
This means that just about any biomass source can be gasified and
converted to ethanol. While I have managed to dig up other research on
this technology using different bugs to BRI, not a lot of effort has
been put into this technology. This is surprising as gasification is a
well known process and if it is as simple as fermenting the syngas, then
surely this should be a technology that should be receiving a lot more
attention? I know that Brian is fanatical about producing alternative
fuel/energy that is cost effective. Would this route be competitive
Brian? 
Kind regards
Rex