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hydrogen from algae...

hydrogen from algae... - Chemistry Forum

hydrogen from algae... - Chemistry Forum. Discuss chemical reactions, chemistry.


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Old 01-18-2004, 10:35 AM
Art Ickles
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Default hydrogen from algae...



>Dr. Melis from UC Berkeley discovered a way to produce hydrogen from

First stop, [Only registered users see links. ]. From the berkeley web pages:
[Only registered users see links. ]

Melis A and Happe T (2001) Hydrogen Production: Green Algae as a Source of
Energy. Plant Physiol. 127: 740-748

Zhang L, Happe T and Melis A (2002) Biochemical and morphological
characterization of sulfur-deprived and hydrogen-producing Chlamydomonas
reinhardtii (green alga). Planta 214: 552-561

Melis A (2002) Green alga hydrogen production: progress, challenges and
prospects. Intl. J. Hydrogen Energy 27: 1217-1228

Also: US Patent Appl: 20010053543
Hydrogen production using hydrogenase-containing oxygenic photosynthetic
organisms. See esp Fig 3. "Hydrogen gas accumulation was measured with the
same setup at later times, following the onset of anaerobiosis in the sealed cultures
(Stage 2). The rate of hydrogen gas accumulation (FIG. 3, H.sub.2) was estimated to
be about 2 ml H.sub.2 h-1 (equivalent to 4.1 mmol H.sub.2 (mol Chl).sup.-1
s.sup.-1), which is less than 20% of the rate of O.sub.2 gas collected in the inverted
graduated cylinder (FIG. 3, O.sub.2)."

Zhang LP, Melis A (2002) Probing green algal hydrogen production
Phil Trans Royal Soc of London Series B - Biol Sci. 357 (1426): 1499-1507
"For the first time, to our knowledge, significant amounts of H-2 gas were
generated, essentially from sunlight and water. Rates of H-2 production could
be sustained continuously for ca. 80 h in the light, but gradually declined thereafter."

"The rate of H2 production was fairly constant at 2.5 ml h 1 during the 2760 h
period. This is the equivalent of ca. 5 mmol H2 (mol Chl) 1 s 1, ..."


If you don't have journal access, you can get Melis' contact info from the web
page and ask him for reprints or PDFs.






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Old 01-20-2004, 06:25 PM
Mike Darrett
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Default hydrogen from algae...

[Only registered users see links. ] (Art Ickles) wrote in message news:<[Only registered users see links. ]>...


Thanks for the info. No I don't have journal access (unless I drive
to the local university).

3 mL H2/h/L rxtor... ah, I was afraid of that... well, let's see... in
order to size a reactor to produce 1 megawatt of power... to a first
guess:

X L rxtor x (.003 L H2/L rxtor/hr) x (1 mol H2/22.4 L H2) x (242,000
J/mol H2) x (1 hr/3600 s) = 1E6 J/s

X -> 111,000,000 L of reactor (or 29 million gallons) just for one
megawatt of electrical power.

This of course neglects the 10% typical efficiency of internal
combustion engines, but Melis et al. say H2 production rate can be
increased 10x, so I will allow these two to cancel.

29 million gallons... hmm... let's compare that to Haubenschild Farms'
methane digester, which makes electricity from cow poop (essentially
digested grass):

[Only registered users see links. ] (page 23)

They can produce about 100 kW from 350,000 gallons of reactor. Scale
that up x10 (just build ten Haubenschild reactors in parallel): 1 MW
from 3.5 million gallons.

About one order of magnitude smaller than the algae hydrogen
reactors... hmm...

Again, thanks for the info.

Mike
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