12 May 2008

Furfural from Bagasse, and the Algae Shade Wall

Furfural is a diesel substitute that can be produced from bagasse--the hemicellulose "waste" byproduct of sugar manufacture from sugar cane. Furfural is produced from bagasse by steam distillation, water separation, and purification.
An alternative biofuel, called furfural, is gaining new levels of attention because, like cellulosic ethanol, it is produced from waste biomass such as sugar cane bagasse. After pressing cane for sugar, furfural is produced by steam distillation; it has been produced since the 1920s on a commercial basis and imports for $2.24 per gallon. Avantium has successfully tested furfural as a diesel substitute. Avantium branded its furfural-based biofuel as Furanics, and tests showed a significant reduction in soot emisions and and elimination of sulphur emissions, when compared to conventional diesel. __BiofuelsDigest
On the algal biodiesel front, attempts to scale up production of oils from algae are running into the "shade wall" problem: too much algae in the mix blocks the sunlight needed to grow more algae. Algae growers are successful in using algae for water purification, however, as algae grows quite well in waste water. This Biofuels Digest article provides a good rundown on current algae biofuels research. Current production costs for algal biodiesel are near $20 a gallon, revealing how far algae research and development must go to be viable. Of course, if speculators and oil dictators have their way, gasoline itself will cost $20 a gallon at the pump soon. That is not likely, however, since Coskata and other cellulosic ethanol producers are promising to make ethanol at costs of $1 a gallon within the next 2 to 3 years.

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Blogger The Irrefutable Fool said...

Just for discussion purposes there is an analysis (here: http://www.nanostring.net/Algae/CaseStudy.pdf) making the case that 10000 gallons per acre annually is impossible given the efficiencies of algea, the usable radiation spectrum, the number of photons used in the fixing reaction, and so on. The conclusion is that algae biodiesel would be profitable at 800 bbl only.

I am a big fan of the idea of domestic fuel production ( "you can't fund both sides of a war and win") but the study raises some serious questions. Anyone see any big holes in the studies logic?

Monday, 12 May, 2008  
Blogger IConrad said...

Yes, there's a glaringly huge one. It's focused on photobioreactors, such as GreenFuels'.

Open ponds and vertical columnar growing methods operate on wholly different 'mechanisms' -- they each have their own drawbacks but they have nothing remotely like photobioreactors do.

Monday, 12 May, 2008  
Blogger al fin said...

Nice article, TIF. We need to look at such case studies not as deal-breakers, but as guideposts. The energy inefficiencies involved are similar to the energy inefficiencies involved in other photosynthetic processes, eg biomass.

From the standpoint of efficiency, photovoltaics comes out on top. But PV doesn't have good storage on any scale--from the utility scale down to the vehicular scale. So PV loses to biomass for now. It isn't clear whether algal processes will scale up before better batteries are invented or not.

I suspect it will be 2030 before we get the kind of batteries we need to replace the internal combustion engine with all-electric drive.

So in that 20 years, with oil prices in extreme flux due mostly to political and speculative drivers, we will need liquid biofuels. Whether they come more from cellulose thermochemical processes or from oil producing species such as algae, remains to be seen.

The local and regional approach to bio-energy is the best. Start small, expand as is profitable. If you create a good technological and business model, others will imitate what you do, and improve on it.

Tuesday, 13 May, 2008  

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