Biofuel made from power plant CO2

[kenvlach]

Someone's come up with the ideal solution to the issue of CO₂ aka 'greenhouse gas' generation: Attach a greenhouse!!! Brilliant in its simplicity. One might think land is an issue, but with algae, maybe tall lighted tanks?

Biofuel made from power plant CO₂
by Phil Mckenna, in New Scientist, issue 2572, 07 October 2006.

"Power plants emit carbon dioxide, algae make sugar and oil out of it. It's time to put the two together
"IF YOU'RE working at a power plant, you just saw your carbon dioxide turned into something you can drive home with." So says Isaac Berzin of GreenFuel Technologies in Cambridge, Massachusetts, which is developing a way of producing biofuel from the noxious emissions of power plants.

Two of the world's greatest energy users are electricity generation and transport. Both are responsible for huge quantities of greenhouse gas emissions, as most power plants and vehicles still rely on fossil fuels. Now GreenFuel and others are hoping to marry the two together with an emerging technology that uses a by-product of one to supply fuel to the other. Doing so could dramatically reduce their overall carbon dioxide emissions.

At the heart of the technology is a plastic cylinder full of algae, which literally sucks the CO₂ out of a power plant's exhaust. The algae can in turn be converted into biofuel, creating ..."

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For more info, see

http://www.greenfuelonline.com/technology.htm

I'm sure you're all thrilled with the idea. Add some fish to the tanks, call it an aquarium and charge admission. Or go fishing while you work!
Ken

 

[unclesyd]

The fish would eat the algae.

Several years ago I saw some bench scale experiments trying to do essentially the same thing. As far as I know nothing came of it.

In the late fifties we used CO2 from a Girbotol H2 plant to enhance algae growth in a waste treatment process to lower the N and P to acceptable levels. It ran for several years. I don't know the efficiency of the process or if anyone cared as the CO2 was free to the waste group. The gut the developed our process left and went to a major university where he continued to study the process. I don't think anything ever came of his attempts to utilize CO2 other that generate some grants.

What was the big show out west that was going to recycle CO2 in big glass house?

 

[ScottyUK]

kenvlach,

There's a similar idea employed in some commercial (industrial?) greenhouses in the UK: typically a small (<50MW) CHP plant burning natural gas in reciprocating engines uses a waste heat recovery system to provide MPHW piped to provide heat to the greenhouses, and the CO₂-rich exhaust is ducted into the greenhouse to provide a warm atmosphere which the plants love. The electricity generation is almost a byproduct of the process.

I was working on one of these engines a couple of years ago through a tie-up (or was it a stitch-up?) with a company my employer has close relations with. I have never seen so many tomato plants. They could have filmed 'Day of the Triffids' in there. And it's tom-ah-toe, just for clarity!


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Sometimes I only open my mouth to swap feet...

 

[cryotechnic]

In Holland (the Netherlands) there is a very succesfull project like this.
They used a large old (not more in use) pipeline that runs from Rotterdam to Amsterdam. This pipeline runs through a very large greenhouse array, and starts close to a oilrefinery.
The hydrogenplant (steamreformer) at the refinery produces very pure CO2 as a byproduct.
So what they did, they've placed a few compressors, and from the mainpipeline they connected the greenhouses.
Instead of extra heating during the summer to produce CO2 for the plants they take the CO2 from the pipeline.
By the way, the CO2 is not used for heating, but the plants use it for the photosynthesis proces to grow.
Ofcourse, at many processes CO2 is released but the problem is that it's not allways pure enough to use it in the greenhouses.

Unfortunally the site of the company is in Dutch only, but anyway:

http://www.ocap.nl

"Math is the ruler of your potential succes...."

 

[athomas236]

Looked at the website but there seems to be a lack of process data and costings that would help show the viability of the process.

The principle seems to be that CO2 in flue gas is used to grow algae which is turned into a fuel which is then burned releasing the CO2 again. It is not clear to me if this, at the end of the day, reduces CO2 emissions or just delays the moment at which they are released.

athomas236

 

[cryotechnic]

You're right, the CO₂ circle of plants is neutral. What the plants need to grow, will be released later.

In old days, the greenhouse owners fired up they're heaters during the summertime to produce they're own CO₂ in the greenhouse. So they didn't use it for the heat, but they want the CO₂.
At the same time, the hydrogenplant was venting his CO₂ fluegas.
So the benefit of this project is:
-Instead of venting the CO₂ (at the hydrogenplant), and at the same time producing the CO₂ local (at the greenhouses) they are using the CO₂ from the hydrogenplant.
-There is no waste of natural gas (which is used in the heaters).
-The CO₂ which is deliverd to the farmers is much more pure than the CO₂ they produced they're self. Resulting in a bigger yield per meter².

Some farmers had a tank with liquid CO₂ on they're premisses (instead of using they're heater). The benefits here are:
-No more transportation by truck
-No more liquefication costs for the CO₂
-No more release of CO₂ by the trucks during transportation.

Cryotechnic

"Math is the ruler of your potential succes...."

 

[davefitz]

I tink the important item missing from teh discussion is a descriptionof the raction rate, and the energy requirements.

The burning of fossil fuels and oxidizing carbon to CO2 releases an enormous amount of energy. From a simple energy balance stndpoint, you cannot just wave some algea at the gaseous CO2 and expect it to revert to a stable form of non-gaseous carbon without significant energy input. I f you are using solar energy as the energy input, I think the rate of the porcess would be very slow- this info would reveal the weak point of this magical answer to all of our problems.

 

[kenvlach]

davefitz is correct; a fossil fuels-powered plant creates CO₂ far more rapidly than plants in a standard-style greenhouse could utilize via photosynthesis. But maybe, using algae in very tall, lighted tanks?

The other flaw in inecting large amounts of CO₂ into water is that it lowers the pH. While there are some pH-tolerant algae, scientists are reporting that low pH in ocean waters due to higher absorption of atmospheric CO₂ is interfering with the ability of corals, mollusks, etc. to build shells of calcium carbonate.