[Gasification] Algae

Mon Apr 2 09:14:46 CDT 2007

Rex,

As an "old" heat sealer of plastics, I can tell you that a heat sealed joint 
is a stress riser, usually lacks flexibility and has reduced strength.  The 
better way is to join the sheets using ultrasonic welding.  It does the 
bonding without the heat which tends to keep the flexiblizers and additives 
in the plastic.

Ultrasonic welding lends itself to robotic processes and can be accomplished 
at many inches per second in both wide and narrow seams in complex shapes.

Just a bit of facts from my experience.

Thank you for your ongoing information on the S. African algae-oil process.

Art Krenzel

----- Original Message ----- 
From: "Zietsman, Rex" <Rex at Process.co.za>
To: <gfwhell at aol.com>
Cc: <Gasification at listserv.repp.org>
Sent: Sunday, April 01, 2007 11:36 PM
Subject: Re: [Gasification] Algae

> 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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