Hello! Woke up in a visionary state of mind today and thought I'd put my thoughts out for display! In order to achieve world dominance, or rather crush it, we need infinite supplys of raw material apart from the ultimate meta-fabber that makes itself on all levels. Obviously supporting dictatorships in oilproducing countries is not the solution. Most biofuels also suffer from the problem of eating up farmland and thus, direcly or indirectly taking food away from poor people. Apart from the moral aspects of driving your ethanol-gulping SUV to the grocery store to buy some mayonaise (how many bowls of rice did you make not happen going back and forth?) we also have the problem of nitrides and over-fermentation. Nukes and fusion is all nice and dandy but before we get there we are likely to have nothing to make stuff out of left (read: no oil no plastics) It seems that green algae could be the solution to all of the above. According to www.oilgae.com the green algae run on sunshine and CO2 and nothing more. The nourishment used to grow them can be filtered out and recycled infinitely! Also the algae can make use of dirty water or even saltwater, deserts would be a great place to grow if the systems could be made closed-loop. Another California based company (Sapphire Energy) has made claims that they will make crude oil from algae, suitable for the present-day refineries, making diesel and gasoline just as usual, currently they say at prices of refining hard-to-get-to oil. My question to the brain-trust in this forum: Doesn't this knowledge belong in the public domain? Anyone in for growing green slurry in their backyards this summer? (Or the coming summer for the southern hemisphere) Energy figures for those interested, calculating roughly at 1kW per m^2 of land and conservatively at 2000 hours of sun per year gives us a potential of 20 liters of biofuel assuming an energy content of 10kwh/liter and a 10% effieciency of conversion rate. It seems that a moderate 100 m^2 rooftop reactor could heat a home for a year. I know there are some talented people here, please tell me what you know about this! Especially I like the pragmatic approach of people on this forum! https://reprap.org/forum/read.php?70,12574,12574#msg-12574 Sun, 14 Jun 2026 09:53:16 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?70,12574,12979#msg-12979 https://reprap.org/forum/read.php?70,12574,12979#msg-12979 [www.youtube.com]


You could make a lot more oil a lot cheaper if you just grew plants to make sugar on a wide area and fed the sugar to the algae to get a 1000x greater yield than with sunlight alone. Your bioreactors could be incredibly small for the output they would produce.]]> rodzite Plastic Extruder Working Group Sat, 07 Jun 2008 05:42:30 -0400 https://reprap.org/forum/read.php?70,12574,12849#msg-12849 https://reprap.org/forum/read.php?70,12574,12849#msg-12849
mimarob Wrote:
-------------------------------------------------------
> Am I right to assume that people doing ponds that
> are 25 cm deep could expect to get 1.6g/liter/day
> which means that in "my" pond structure I could
> get
> 100 x 0.25 x 1000 x 1.6g = 40000 g = 40 kg of
> green goo a day?

It's more like 2.5kg, the rationale for that figure is in the post above. This changes all your calculations.

> Assuming I would live near the equator take [40
> kg/day] x 365 = 14600 kg
> which would be almost 15 tons of the stuff in a
> year?

912.5kg, as you said in one of your posts earlier in this thread... "My rooftop example would then give about 900 kg of biomass for a year."
That much algae can yield 365kg of oil at an extraction efficiency of 40%; or about a hundred gallons of oil per year.

> Energy content of the oil would be about 10kwh/kg
> (just a wild approximation)

Just double-checking your numbers, biodiesel has 35.7MJ/L, or 135MJ/gallon worth of energy. Your approximation was spot on, that's 9.9kWh/L.

Thus, energy content of 100 gallons of biodiesel is 13.5GJ, or 3,750kWh.

> In one year we "produce" 70000 kwh (sorry for
> being to lazy to convert to Joules)
> Assuming again in the equator example a sun influx
> of about 1kw/m^2 we would end up with about 4000
> sun hours under ideal conditions.
>
> The energy input would be 1 x 4000 x 100 =
> 400000 kwh

There are a few solar insolation maps from NREL that show that 5kWh/m2/day in the south-western United States, for example, is a good figure for this, averaged throughout the year. Let's say we get 2000kWh per square meter per year, and, as you did, multiply that by 100... 200,000kWh/year.

> Now with this calculation we end up with an
> efficiency fo 70000/400000 = 17.5 % which is way
> to high by an order of magnitude!

Now we have an efficiency of almost 2%. :)]]> PhycoFalcon Plastic Extruder Working Group Thu, 05 Jun 2008 08:14:43 -0400 https://reprap.org/forum/read.php?70,12574,12826#msg-12826 https://reprap.org/forum/read.php?70,12574,12826#msg-12826
... recently i read a tech-article, where someone managed to 'clean' carbonize any organic stuff as vegetables or household-droppings.

He simply used a pressure-cooker filled with the vegetables, some water and citric acid as catalysator and heated this for 12 hours or so up to 120]]> VDX Plastic Extruder Working Group Thu, 05 Jun 2008 04:06:06 -0400 https://reprap.org/forum/read.php?70,12574,12824#msg-12824 https://reprap.org/forum/read.php?70,12574,12824#msg-12824
Does that mean that it is not photosynthesis itself that is the limiting factor but more if the "farm" is closed or open and how much you manage to circulate the algae?

We got a few things working in our advantage:

* Exponential growth
* Future reprap technology to build ponds

On the bad side:

* Converting the algae soup to useful oil and then into plastic means a lot of techically advanced processing steps, some which contain dangerous chemicals?]]> mimarob Plastic Extruder Working Group Thu, 05 Jun 2008 03:46:43 -0400 https://reprap.org/forum/read.php?70,12574,12777#msg-12777 https://reprap.org/forum/read.php?70,12574,12777#msg-12777
A good reason to do this calculation is to give you an idea as to how much culture media you will need to make each day. You have 25000L of culture over 100m2 of open pond. Then you harvest half (a healthy culture will double about once a day), and replace the other half with fresh media. So, you need to add 12500L of media each day, and dewater/filter 12500L of culture each day. The return? 2.5kg by area, or 2.25kg by volume. This is vs a photobioreactor, which you will need to replace only 750L in the same area, if that. I haven't yet designed this rooftop PBR, so I can't give you exact dimensions.

As a disclaimer, these calculations are just based on experimental data, so it's really up to multiple factors, in the end, as to what you actually come up with. For 100m2, it's not a lot, though. Most people calculate for an acre, or a little over 4000m2. That's when yield figures for fuel become more reasonable, but the cost of covering an acre in PBRs or even ponds is something that's being worked on by some of the brightest in the industry.]]> PhycoFalcon Plastic Extruder Working Group Wed, 04 Jun 2008 11:40:36 -0400 https://reprap.org/forum/read.php?70,12574,12771#msg-12771 https://reprap.org/forum/read.php?70,12574,12771#msg-12771 to go back to primary school...

So anyway.

Am I right to assume that people doing ponds that are 25 cm deep could expect to get 1.6g/liter/day which means that in "my" pond structure I could get
100 [m^2] x 0.25 [m] x 1000 [l/m^3] x 1.6g = 40000 g = 40 kg of green goo a day?

Assuming I would live near the equator take [40 kg/day] x 365 [days] = 14600 kg
which would be almost 15 tons of the stuff in a year?

Then assuming half of it can be made into oil. I would have about seven tons
of plastic?

Energy content of the oil would be about 10kwh/kg (just a wild approximation)

In one year we "produce" 70000 kwh (sorry for being to lazy to convert to Joules)
Assuming again in the equator example a sun influx of about 1kw/m^2 we would end up with about 4000 sun hours under ideal conditions.

The energy input would be 1 [kw/m^2] x 4000 [h] x 100 [m^2] = 400000 kwh

Now with this calculation we end up with an efficiency fo 70000/400000 = 17.5 % which is way to high by an order of magnitude!

Any comments?]]> mimarob Plastic Extruder Working Group Wed, 04 Jun 2008 07:42:36 -0400 https://reprap.org/forum/read.php?70,12574,12766#msg-12766 https://reprap.org/forum/read.php?70,12574,12766#msg-12766
I was doing this calculation off of a tubular photobioreactor that could be mounted on your roof.

But if we're talking about ponds, the 25g/m2/day figure is what you want to use.

Your math towards the amount of medium in a pond isn't right though. I had trouble with that one the first time I took a crack at it too, but it's good to think in terms of liters. 1000L in a cubic meter, 25% of that is 250L.

Also, some very good books already available are:
[www.amazon.com]
[www.amazon.com]]]> PhycoFalcon Plastic Extruder Working Group Wed, 04 Jun 2008 05:11:07 -0400 https://reprap.org/forum/read.php?70,12574,12761#msg-12761 https://reprap.org/forum/read.php?70,12574,12761#msg-12761 > 25kg of biomass per day from one cubic meter of medium given the numbers
> established in my earlier post. Your entire rooftop system of tubes, 100m2,
> would
> contain about 1500L total volume, or 1.5m3. It's not that much, but that's good,
> since that keeps medium preparation costs low! smiling smiley

Hello Alex!

I was probably mis-quoting your previous post, you mentioned a figure of 164 kg of bio-diesel per year and I assumed it was for the 100 m^2 rooftop example so I divided it with 100 to get the per-square-meter yield, hence the 1.64 kg.

Looking back at these figures make me feel I would get better yield growing old-fashioned potatoes so obviously I made a misstake somewhere...

What exactly do you mean when you say 25g/m2/day ? At which pond depth is this achieved?

Hmm, but wait now, if the pond is 20-30 cm, say 25 cm. Then the volume of the
arrangement would be 0.25*100 = 25 m^3 ?

I to will have to read prof. Edwards book when it comes available :-)]]> mimarob Plastic Extruder Working Group Wed, 04 Jun 2008 01:51:56 -0400 https://reprap.org/forum/read.php?70,12574,12722#msg-12722 https://reprap.org/forum/read.php?70,12574,12722#msg-12722 -------------------------------------------------------
> So is it the photons in the sunlight that is the
> limiting factor to the photosynthesis or is it the
> limited amount of CO2?

It's usually CO2 that is the limiting factor, but other limiting factors could be macronutrients (NPK-- nitrogen, phosphorous, and potassium), trace metals such as iron, sunlight (though algae need only 10% full sunlight), high oxygen concentration, and even competition from contaminant algae, bacteria, and protozoa, just to name a few of the challenges one might face when growing algae in a photobioreactor.

> It is anyway most certain to need a ventilation of
> some kind and so a filter to keep the alien algae
> away and a few pumps so we need another field of
> electriciy solar panels *sigh*

It would be wise to install a good, replaceable filter on your air pumps.

> Obviously the algae also needs to be circulated,
> which leads to a question I had for some time: How
> deep does the pond need to be to make optimal use
> of the sunlight?

If you're going with a pond, most commercial raceway operators use depths of only 20-30cm. That's 8-12 inches. They use a paddlewheel to keep the mixture circulating, and this setup works very well and is proven. There are, however, issues with evaporation and environmental factors, as we have discussed.

> Another thought I had was about growth, we know
> the repraps can grow quite quickly.
>
> When it comes to filling space, suppose we can
> make a 1m^2 bioreactor complete with a plastic box
> weight 1.64 kg, we could double the amount of
> reactors each year, provided we don't make any
> repraps.

Where did you get that number? One cubic meter is 1000 liters. You could produce 25kg of biomass per day from one cubic meter of medium given the numbers established in my earlier post. Your entire rooftop system of tubes, 100m2, would contain about 1500L total volume, or 1.5m3. It's not that much, but that's good, since that keeps medium preparation costs low! :)

> Considering I spent 5 liters of fuel this morning
> just getting to work (and an unknown amount just
> being there) we'd need a pardigm shift to go with
> it :-)

It takes 25MJ of energy to make one kilogram of plastic. One liter of gas has 34MJ of energy, so making plastic is good too. :)]]> PhycoFalcon Plastic Extruder Working Group Tue, 03 Jun 2008 03:18:05 -0400 https://reprap.org/forum/read.php?70,12574,12721#msg-12721 https://reprap.org/forum/read.php?70,12574,12721#msg-12721
Sorry, when I said "glass" I meant something like plastic transparent sandwich wrap.

Anyway if one could get a way with a material that thin, it might not be so much of a problem to replace it every season.

So is it the photons in the sunlight that is the limiting factor to the photosynthesis or is it the limited amount of CO2?

I read somewhere that they where going to try leading the CO2 from nearby powerplants into the algae, but thats obviously not sustainable.

It is anyway most certain to need a ventilation of some kind and so a filter to keep the alien algae away and a few pumps so we need another field of electriciy solar panels *sigh*

Obviously the algae also needs to be circulated, which leads to a question I had for some time: How deep does the pond need to be to make optimal use of the sunlight?

Another thought I had was about growth, we know the repraps can grow quite quickly.

When it comes to filling space, suppose we can make a 1m^2 bioreactor complete with a plastic box weight 1.64 kg, we could double the amount of reactors each year, provided we don't make any repraps.

Considering I spent 5 liters of fuel this morning just getting to work (and an unknown amount just being there) we'd need a pardigm shift to go with it :-)]]> mimarob Plastic Extruder Working Group Tue, 03 Jun 2008 02:44:37 -0400 https://reprap.org/forum/read.php?70,12574,12717#msg-12717 https://reprap.org/forum/read.php?70,12574,12717#msg-12717 [www.arkema-inc.com]

Using the process described above, that may be a starting point towards creating Rilsan on your own. :)]]> PhycoFalcon Plastic Extruder Working Group Mon, 02 Jun 2008 23:12:19 -0400 https://reprap.org/forum/read.php?70,12574,12716#msg-12716 https://reprap.org/forum/read.php?70,12574,12716#msg-12716 -------------------------------------------------------
> I know of no transparent
> polymer that can stand direct sunlight for more
> than a few months. It doesn't sound anywhere near
> practical. Wish it was, mind. :(


There is at least one. It's called Tefzel and it isn't cheap.

[www.rwgrayprojects.com]
[www.rwgrayprojects.com]

Now if you could produce it yourself that might be a different matter.]]> rodzite Plastic Extruder Working Group Mon, 02 Jun 2008 22:42:47 -0400 https://reprap.org/forum/read.php?70,12574,12702#msg-12702 https://reprap.org/forum/read.php?70,12574,12702#msg-12702 Forrest Higgs Plastic Extruder Working Group Mon, 02 Jun 2008 13:26:49 -0400 https://reprap.org/forum/read.php?70,12574,12701#msg-12701 https://reprap.org/forum/read.php?70,12574,12701#msg-12701
Almost none of the corporate proprietary stuff is in the public domain.
I've just written a book: Green Algae Strategy: Engineering Sustainable Food and Biofuels
that summarizes both the food knowledge and biofuel knowledge that's public.

some algal species are 84% lipids (oil) but they grow very slowly.
others at 60% oil can be grown quickly.
other species are 60% protein while others are 90% carbs

whoever posted the piece on open ponds was right: too much evaporation plus opportunistic algae invade pond, create weedy algae which must be replaced. Closed cultivated algae production systems, CAPS, are the way most firms are going. Far more productivity and more control over growing variables.

Very little exists on actual production outside of academic papers and one edited book by Amos Richmond (Israel) on actual production metrics.

My book Green Algae Strategy will be availabe on Amazon in August.

Mark Edwards
Professor, Arizona State University
drmetrics@cox.net]]> Mark Edwards Plastic Extruder Working Group Mon, 02 Jun 2008 13:13:59 -0400 https://reprap.org/forum/read.php?70,12574,12699#msg-12699 https://reprap.org/forum/read.php?70,12574,12699#msg-12699
Check it out here:
[www.omnexus.com]]]> PhycoFalcon Plastic Extruder Working Group Mon, 02 Jun 2008 12:35:38 -0400 https://reprap.org/forum/read.php?70,12574,12697#msg-12697 https://reprap.org/forum/read.php?70,12574,12697#msg-12697 -------------------------------------------------------
> BTW, I talked to a guy from the middle east a few
> years ago. He told me that it was possible through
> some crude process to make some kind of plastic
> "glass" out of oil, which was then used for
> greenhouses to grow food. The plastic glass would
> only last about one season under the dessert sun
> though.

It's not glass. Greenhouse growers without a lot of capitalisation often use plastic films like polyethylene. They last about one season. Around here, they cover whole open fields with polyethylene and gas the root nematodes with methyl bromine. For high value crops like strawberries they cover the fields and plant the sets in holes in the film. That cuts way down on the amount of cultivation to keep weeds under control that they have to do and thus the number of illegal aliens they have to hire.]]> Forrest Higgs Plastic Extruder Working Group Mon, 02 Jun 2008 11:16:38 -0400 https://reprap.org/forum/read.php?70,12574,12696#msg-12696 https://reprap.org/forum/read.php?70,12574,12696#msg-12696
The 25g/m2/day figure is simply for dry biomass. If you are clever, you can get about 30-40% of that as oil. Since a gallon of vegetable oil weighs about 3.4kg, you should be able to extract about 1 gallon vegetable oil from the algae per meter per year.

Now, let's say we've got a 100m^2 area, like your roof, and we effectively covered this with tubes. Assuming that your bioreactor will produce 1.6g of biomass per liter (as per the paper I mentioned earlier, referenced to the 25g/m2/day spirulina figure), you'd need to process half of the 15.6L of algae per m2 of reactor space. You process half because you harvest half the solution, fill it in with fresh medium, and then let the culture double again (usually over the course of one day). So, we're processing about 781L of algae each batch, about 200 gallons per day. Out of those 200 gallons should come about 1.25kg of algal biomass (which makes sense; that's 0.625% of the solution, as algae is very dilute, even in the dark green stuff). This means you can get about 67 gallons of biodiesel from your roof-top system per year.

You might be able to get starches from some of the rest of the processed material, which can then be used for ethanol production, to make up the other 10-20% of your biodiesel (the Renewable Raw Materials paper recommends using 'an excess' of methanol to produce Rilsan plastic).

At any rate, let's say we can use 50% of the algae in making your biodiesel. That's 1.38lbs of biodiesel, or less than .2 gallons per day. Also, accounting for glycerine loss, you take 10% off of that figure. You'd need an entire week to produce 1 gallon of biodiesel from your reactor.

Most people would stop here, and say-- damn, algae makes so little fuel, it's impractical for powering my big SUV. That's true. But we're in the RepRap community now, and RepRaps can be solar powered, so they don't need expensive fuel. But they do need plastic, and plastic is much more expensive than fuel! I read somewhere on this forum that PLA costs $75 / 2kg spool. B100 fuel costs, today, in Denver (Courtesy of Shoco Oil), $5.43/gallon. So, that's $1.60 / kg. The economics work out to be in much greater favor for plastic production. Even ABS plastic is $20/kg, according to the rrrf.org site.

I don't know the losses in the Rilsan plastic production process, but let's just guess and say we can turn 80% of the biodiesel into plastic. So, if we can make 164kg of biodiesel per year, (that's with esterification, glycerine, and extraction efficiencies accounted for), it would be valued at about $5000. That's enough plastic to make about a 100 RepRaps, and if you sold those as parts, you could double your money. And all that off of one roof! :)

If the process is not economical, in a capitalist economy, it's not sustainable. It's a good idea to think about sustainability, since even if the process is renewable (which is a tough enough feat to achieve by itself!), you may find it's not possible to do it in a sustainable manner; such as using flue gas from coal plants as a CO2 source, or chemical fertilizers to make your culture medium; or using biosolids from wastewater treatment plants (wastewater treatment uses 1% of our total energy resources here in the USA.); these sort of things aren't sustainable in the long run. You've gotta be thoughtful about how you do this, and cover all the angles.]]> PhycoFalcon Plastic Extruder Working Group Mon, 02 Jun 2008 10:58:54 -0400 https://reprap.org/forum/read.php?70,12574,12694#msg-12694 https://reprap.org/forum/read.php?70,12574,12694#msg-12694
So assuming good sunlight we could get around 9 kg of it per square meter and
year.

My rooftop example would then give about 900 kg of biomass for a year.

Is that dry substance and oil or is it before we remove the water?

Any guess on its energy content?

I made some rough guesses and ended up about at about 10W assuming it could be
burned as fuel (and the smell didn't kill you :-)

What other refinements are needed to make a useful product out of this?

Assuming it could make into behaving like crude oil, all other processing stages would already be well-known.

BTW, I talked to a guy from the middle east a few years ago. He told me that it was possible through some crude process to make some kind of plastic "glass" out of oil, which was then used for greenhouses to grow food. The plastic glass would only last about one season under the dessert sun though.

Bioreactors reproducing themselves...

Erik.. Dreaming away at work...]]> mimarob Plastic Extruder Working Group Mon, 02 Jun 2008 09:19:30 -0400 https://reprap.org/forum/read.php?70,12574,12687#msg-12687 https://reprap.org/forum/read.php?70,12574,12687#msg-12687
If the the fungus powder can be extruded as something resembling the properties of a polymer, that's cool, but I'm not sure that would work. You should do some research into that.

I've heard of fungus being used to turn oil and alcohol into biodiesel, which is the first step of the renewable Rilsan process I detailed in an earlier post, however, you still need a source of oil and alcohol, which algae can provide. :)
[blog.wired.com]]]> PhycoFalcon Plastic Extruder Working Group Mon, 02 Jun 2008 07:35:16 -0400 https://reprap.org/forum/read.php?70,12574,12686#msg-12686 https://reprap.org/forum/read.php?70,12574,12686#msg-12686
the mirrors shouldn't focus the sunlight to much, they should better distribute the light between the tubes, otherwise the tubes would shadow each other.

Tubes because of the same reason - in a big tank only the outer algaes receive the full sunlight - with tubes you have better distributing ...

For the funghi: - besides of energy you need fabbing material too, so maybe it's easier and more efficient to use dried/baked and powdered funghi as fabbing powder?

Viktor]]> VDX Plastic Extruder Working Group Mon, 02 Jun 2008 07:26:34 -0400 https://reprap.org/forum/read.php?70,12574,12684#msg-12684 https://reprap.org/forum/read.php?70,12574,12684#msg-12684 -------------------------------------------------------
> Hmm, so I'd better lower my expectations one order
> of magnitude or so, damn I have to stop reading
> thoose news-from-a-startup-company texts...
>
> So we are down to a 10W/m^2 production rate and
> that is in a closed tank under optimal
> conditions... o well, back to the drawing board
> :-)

That measurement you posted is used as a measure for solar insolation; you didn't give any period of time for this "rate"; and you only get 10W/m^2/day around the equator. Here (Colorado) it's more like 5W/m^2/day (averaged throughout the year). Plus, that's only really relevant towards solar panels, since with algae production, it's often measured in g/m^2/day. Spirulina, when grown in tubular photobioreactors, typically yields 25g/m^2/day, as can be found in the paper "Microalgal mass culture systems and methods: Their limitation and potential", by Yuan-Kun Lee.

Viktor, I'm wary of systems that focus solar energy onto algae, as that is liable to overload their photosystems and bleach out the algae. Algae need only ~10% of full sunlight. I would never use UV bulbs to grow algae, either.

I can't say I know much about fungus, other than that it is a heterotroph, meaning, it eats food rather than makes it. That might make it more productive than algae, but I like algae since it adds energy to the system rather than reducing it by another trophic level as the fungus would.]]> PhycoFalcon Plastic Extruder Working Group Mon, 02 Jun 2008 06:56:35 -0400 https://reprap.org/forum/read.php?70,12574,12680#msg-12680 https://reprap.org/forum/read.php?70,12574,12680#msg-12680
For optimal results you have to arange two separate areas - one exposed to the light, another fully darkened, as most algae needs day-night-cycles ...

Maybe for generating fabbing-material you should focus more on funghi than on algae?

You can grow many kilograms of (some tasty too ;) ) mushrooms in your basement, when wetting some straw-blocks and seeding the right spores ...

Viktor]]> VDX Plastic Extruder Working Group Mon, 02 Jun 2008 04:23:56 -0400 https://reprap.org/forum/read.php?70,12574,12679#msg-12679 https://reprap.org/forum/read.php?70,12574,12679#msg-12679
So we are down to a 10W/m^2 production rate and that is in a closed tank under optimal conditions... o well, back to the drawing board :-)]]> mimarob Plastic Extruder Working Group Mon, 02 Jun 2008 03:34:34 -0400 https://reprap.org/forum/read.php?70,12574,12645#msg-12645 https://reprap.org/forum/read.php?70,12574,12645#msg-12645 -------------------------------------------------------

> I try not to get too down about it though, since
> the possibilities are there, and maybe by the time
> I get my PhD, things should look more promising in
> the field.
> :)

ROTFLMAO! I remember thinking exactly the same thing about algae harvesting when I was finishing up my Master's thesis on solar energy conversion efficiencies...

...back in 1974. (:D]]> Forrest Higgs Plastic Extruder Working Group Sun, 01 Jun 2008 10:48:20 -0400 https://reprap.org/forum/read.php?70,12574,12629#msg-12629 https://reprap.org/forum/read.php?70,12574,12629#msg-12629 -------------------------------------------------------
> It doesn't sound anywhere near
> practical. Wish it was, mind. :(

*sigh*
I know how you feel, man. Some days it feels that way too. Did I mention that algae is only about as dense as 1g/L? That's usually doubles every day, mind you, which is great, prolific even, but it's still 0.1% of the total volume, and harvesting is only one of the issues involved in sorting all this out, in addition to finding the right strain and growth conditions, production of the algal culture, recycling medium, extraction of starch and lipids, processing... The list goes on.
I try not to get too down about it though, since the possibilities are there, and maybe by the time I get my PhD, things should look more promising in the field.
:)]]> PhycoFalcon Plastic Extruder Working Group Sun, 01 Jun 2008 00:17:41 -0400 https://reprap.org/forum/read.php?70,12574,12628#msg-12628 https://reprap.org/forum/read.php?70,12574,12628#msg-12628 Forrest Higgs Plastic Extruder Working Group Sun, 01 Jun 2008 00:03:19 -0400 https://reprap.org/forum/read.php?70,12574,12627#msg-12627 https://reprap.org/forum/read.php?70,12574,12627#msg-12627
There are many different configurations for photobioreactors. Some use tubes, some use bags, some use aquarium-style vessels. I'd suggest a combination of tubes and aquariums for a DIY, homebrew kit.

As a disclaimer, I've never put this into practice; I've only studied algae in the lab and in textbooks. Yes, I'm one of those... You're right to be skeptical of this, as it's still in experimental stages.

The take-home is, eventually someone, a DIY, backyard tinkerer, will get it right. Hopefully they'll share their ideas with the community. There are a lot of resourceful people here building RepRaps, that I think this might be the ideal place to spread the word.

I did some research into bioplastics, and I found an excellent article about using renewable feedstocks from biomass. A good deal of these could be grown at home, if using the proper techniques and equipment. I will give an example. Here is the article:

[www.nt.ntnu.no]

The R-1 portion of synthesis diagram of Rilsan 11 (Nylon-11, PA-11, you may have heard of it...), specifically, the one found on page 8 and described on page 7, is already done by biodiesel homebrewers and co-ops. This is part of a larger process that ultimately ends in creating the polymer, which I will summarize below:
* Algae produce starches and lipids. (not in the diagram, but let's use this as a basis)
* Starch can be fermented into ethanol, which can be used as a substitute for expensive and harmful methanol, and lipids can be extracted from algae (exactly how is a discussion for another day) (this is not in the process diagram, either)
* After esterification, aka "the biodiesel process", (R-1, using lipids, ethanol/methanol, and sodium or potassium hydroxide... aka lye, caustic potash, as a catalyst), biodiesel (methyl/ethyl esters) are sent to be washed in sulfuric acid (S-1, to remove the basic NaOH or KOH catalyst; some homebrewers I know handle this regularly) in order to neutralize the pH.
* The esters are purified (C-2) in order to get the desired biodiesel with a carbon chain length of 18 (C18, which is longer than the average carbon chain length found in diesel fuel, but less than motor oil; however, this is still the stuff of vegetable oil, please don't confuse it with fossil fuels.) The mixture of methanol and catalyst, as well as the quality and properties of the lipids in the esterification step will determine the chain length of your methyl esters. This is to be experimented with, and is why it's handy to have some lab equipment available, such as a gas chromatograph, in the beginning stages, until more commonly available tests, such as the pHLip test, are created for homebrewers. If this is going to be done on the co-op scale, however, a GC is good to have in order to optimize production and get quantitative feedback.
* Next, the C18 methyl ester is send to a pyrolysis chamber (R-2), which is basically a 570-degree F oven. Some perfume gunk is removed from the chamber, dunno what to do with that. More perfume gunk is removed in C-3 and C-4. We really don't want that perfume gunk to be in our polymer.
* In R-3, saponification takes place, which is the same process used to make soap. You can get methanol out of this, since that's what esterified that lipid in the first place.
* In R-4, hydrobromic acid (this may prove to be a challenge due to its acidity constant of -9, which makes it a much stronger acid than H2SO4, with a acidity of -3. For reference, acetic acid (you know, from vinegar) has an acidity of positive 4.76, and water is 15.76.), is added to the result of R-3, to add bromine to the mix. Bromine is present in salt, especially sea salt.
* Finally, in R-5, we're reacting the product with ammonia, which is sent to be cleaned in C-5, and results in your polymer, 11-aminoundecanoic acid.
And I'll bet you thought making biodiesel was hard! :D]]> PhycoFalcon Plastic Extruder Working Group Sat, 31 May 2008 23:56:02 -0400 https://reprap.org/forum/read.php?70,12574,12625#msg-12625 https://reprap.org/forum/read.php?70,12574,12625#msg-12625 Forrest Higgs Plastic Extruder Working Group Sat, 31 May 2008 21:16:14 -0400 https://reprap.org/forum/read.php?70,12574,12623#msg-12623 https://reprap.org/forum/read.php?70,12574,12623#msg-12623
Water is generally an issue with open ponds such as raceways, but not with bioreactors. In general, you only put in what you take out (in a properly engineered system). This actually makes these much more economical for fuel production than any sort of agriculture available today.

For a home system, it might make more sense to use a photobioreactor; though they cost more, they produce a higher algae density, and are better for growing high yield monoculture crops.

I consider a photobioreactor to be more DIY than a raceway pond, since you can more easily tweak productivity on a small scale, and still get the end result of a pond ten times its area.

Another thing about ponds; you mentioned stagnant water-- any raceway enthusiast will tell you that you need a paddle wheel. This is important for many reasons; it mixes the algae so you get better aeration and light coverage, so you don't bleach the top layer of algae (algae need only about 10% of regular sunlight. You need to let the photosystems recover under bright light).]]> PhycoFalcon Plastic Extruder Working Group Sat, 31 May 2008 20:08:09 -0400 https://reprap.org/forum/read.php?70,12574,12621#msg-12621 https://reprap.org/forum/read.php?70,12574,12621#msg-12621 Forrest Higgs Plastic Extruder Working Group Sat, 31 May 2008 19:40:58 -0400