[Gasification] Algae

Mon Apr 2 01:36:13 CDT 2007

Your general idea is spot on. Is suspect they start with a sheet of
clear PVC, fold it over. They will then probably use a die with heaters
on it that will heat seal it along the perimeter and make flow paths
about 4" wide. They then put in an inlet and outlet at top and bottom.
Algae slurry is pumped via manifolds to the sheets that hang vertically
so that the sunlight is not direct -> algae grow better under diffuse
light than direct sunlight. Direct sunlight actually causes growth
inhibition. So hanging vertically is clever as it provides lower direct
incidence/m2 while shoving a lot of surface area onto a small footprint.

The algae(s) will be selected from local algae that are already adapted
to the local conditions. Isolating a performance algae is a time
consuming exercise - it takes about a month to test one. Algaes have to
be tested not only for oil production but that they produce the right
type of oil for bio diesel use. So it is not straight forward. The
algaes that GGS are looking at increase their body weight between 6 and
7x in 24 hours. That is going some. 

They operate the farm with growth during the day (food is added), the
algae is stressed at night (no food and no sunlight) causing the algae
to increase its lipid (oil) content. Before dawn a portion is screened
off (not sure how GGS will do it but a centrifuge will do admirably).
The centrate will be sent back into the circuit and food added so that
the algae can grow during sunlight. Once the solids are removed, (GGS
have their own cagey method of oil removal) the oil can be removed by a
number of ways depending on what you want to do with the residual
carbohydrate and protein. The easiest is to use mechanical means (oil
expeller) where you can burn the residue or you can use something like
super critical CO2 to extract the oil. This leaves the cell walls intact
but will be more expensive. So if the protein is valuable, this may be
the way to go. Finally, the oil is filtered and sent off for bio diesel
production.

The impression I got was that the PVC film was "thick". For thick read
about 500 microns or so. The second impression I got was that they
expected the plastic to last about five years. PVC is generally produced
from fossil fuel mainly because it is the cheapest source of raw
material.

I hope I have answered your queries well enough -> you are sucking my
knowledge down to the bottom of the barrel at this stage. So I may not
be able to answer more detailed questions. Please note that some of the
answers given above are inferred rather than obtained from GGS. 

I also met a mad South African who is seeding an open pond raceway with
local algae. As this system is relatively cheap to install on small
scale (GGS want to start at 5 acres at $1m/acre), it will be interesting
to see how he gets along. I hope to keep you posted.

Rex

________________________________

From: gfwhell at aol.com [mailto:gfwhell at aol.com] 
Sent: 31 March 2007 00:11 AM
To: Zietsman, Rex
Cc: Gasification at listserv.repp.org
Subject: Re: [Gasification] Algae

Rex

I read your expose on the production of Algae by Green solutions  Inc.

This looks like a realistic approach to the production of renewable
energy.

As you were witness to the methods of production, perhaps you could
describe a little more, of the system being used:

 I conjured up, a mental picture of two thin sheets of clear
thermoplastic being bonded together, one sheet upon the other, printing
a pattern by welding. A system using , Hot rollers, or RF. to produce a
capillary of passages for the passage of  liquid. resulting in a
flexible sheet of material capable of being laid down on practically any
suitable  surface for the collection of daylight.

The liquid will be "seeded"  with the required Algae, and re-circulated
through the clear piping matrix, formed between  the welded plastic
sheets.

The growth of the Algae will be dependent upon local conditions, but
will be fast?

If my description is relatively correct.

Please tell,

How often can it be harvested?

How is this done?

How many duty cycles are expected from the plastic?

What thickness and grade is the plastic?

Is it a fossil fuel product?

Regards

GF

-----Original Message-----
From: Rex at Process.co.za
To: phoenix98604 at msn.com
Cc: gasification at listserv.repp.org
Sent: Fri, 30 Mar 2007 2:54 AM
Subject: [Gasification] Algae

Art,

I have just attended a biofuels conference in Johannesburg, South

Africa. A US company called Global Green Solutions

(www.globalgreensolutionsinc.com
<http://www.globalgreensolutionsinc.com/> 

<http://www.globalgreensolutionsinc.com/
<http://www.globalgreensolutionsinc.com/> > ) have, in my opinion,
cracked

the algae challenge. If you recall, I said that the problem with open

ponds was wild algae contamination and that the best way to keep your

strain "pure" was to have a closed system. This makes the challenge of

getting algae slurry into a photobioreactor a problem due to the cost

involved with this type of equipment. Well, GGS have taken thick (500um

or so) clear PVC film, folded it over and heat sealed it around the

outside. Internally they have used heat sealing to make a zig zag flow

path. These pillows are then suspended from racks about 12" apart. The

sheet itself is about 2m tall by about 1.2m wide. Using this

construction method they have managed, at very low cost, to shove

thousands of square metres of area exposed to sunlight into a very small

space: 6000 of these can be fitted onto an acre. Consequently the

capital cost is about US$5/gal (US) with a production cost of about

US$1/gal (US). This is truly remarkable as it is basically independent

of the weather requiring only good sunlight (which we have in abundance

in Africa) and some water. It runs off CO2 in the air but will generate

about a 30% increase in yield if you can add CO2 from other sources eg

combustion. Talk about carbon sequestration! Now the beauty of this

system is that it generates in excess of 180 000 US gals of oil per acre

per year (roughly 1 000 000 litres/acre year). Talk about efficient!

Their current research is into running families of algae together such

that the chemicals excreted by one become the feedstock for the other.

This would enhance/reduce the feed requirements of the lipid producing

algae. So there is a lot going on in advancing the technology. They have

built a demonstration facility in El Paso, TX where they are playing

with the various combinations. Personally, I think this is a tremendous

step forward in the generation of bio derived oil for conversion to

liquid fuel.

The system sequestrates about 1000 tons/year/acre and generates about

1200 tons/year/acre of algae of which about 600 tons is oil and 600 tons

is carbohydrate and protein. After harvesting and pressing, the solids

can be used for various purposes including co-firing, anaerobic

digestion or even gasification if that is what makes sense. The question

then is how do we compress/briquette the solids to make gasifier feed?

Has anyone got any ideas on this? The ubiquitous fireballs?

Rex

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