Shape-Shifting Glass Tubes Give Algae Biofuel A Second Life

May 4th, 2015 by Tina Casey

With global oil prices continuing to slide, the algae biofuel field has been looking a little gloomy of late. However, algae companies have been adapting and branching out into nutraceuticals, cosmetics, and other high-value products. That means R&D is still pushing forward and the industry is poised and ready to catch the next biofuel wave, when oil prices begin their next — and inevitable — upward climb.

We bring this up because our friends over at the algae company Heliae are still fine-tuning their algae production process for maximum efficiency, with the latest development resulting in a 22 percent increase in output — just by changing the shape of a certain glass tube.

The Changing Shape Of Algae Production

For those of you new to the topic, commercial algae production is advancing in two basic directions, each with their own pluses and minuses. One relies on open ponds and natural climate. The other relies on more controlled systems called photobioreactors, typically in the form of long, round glass pipes or tubes.

Heliae deploys elements of both methods, partly to take advantage of waste carbon dioxide to enhance algae growth. The company uses photobioreactors to produce algae seed, which ensures that only the most productive strain makes it to the growth part of the process.

Heliae came across our radar a couple of years ago when it formed a partnership with the Arizona State University Center for Algae Technology and Innovation along with the legacy precision glass manufacturer Schott. ASU is also the lead agency for ATP3, a national public-private algae innovation testbed established by the Obama Administration, so a lot is at stake.

As of last year, Heliae and Schott were anticipating a boost in productivity by replacing the round glass tubing in Heliae’s Helix (TM) algae seed photobioreactor with oval tubes.







Good News For Algae Biofuel

While Heliae has shifted its focus into high-value products, the new oval tubes bode well for more cost-effective algae biofuel production, too.

According to Schott’s press materials, the maximum dry output from the photobioreactor increased by more than 22 percent daily, after the round tubes were replaced with oval tubes.

The basic concept is simple. The oval shape creates a broader cross-section exposed to light, which promotes algae growth. The idea was tested out in computer simulations and now the real-world results are in.

Here’s the rundown from Schott:

An indoor study over multiple cycles in several months found that the algae growth rate per volume increased by more than 45 percent, while the oval shape reduces the total internal volume of PBR tubes by 15 percent compared to standard circular tubes resulting in the overall output-increase stated above.

[snip]

…Furthermore, the final maximum culture density boosted by over 25 percent, enabled by more efficient light exposure of the algae culture.

If you’ve ever seen a photobioreactor facility, you know that they take up a lot of square footage, so being able to wedge more tubes into a tighter area while increasing production is a huge deal in terms of cost-effectiveness.

We’re thinking that what’s sauce for the goose is sauce for the gander, so we’ll be looking out for those oval tubes to make an appearance in other systems. According to Schott, the oval tube endings are designed to be compatible with fixtures engineered for round tubes, making for an easy retrofit.

The Future of Algae Biofuel

As for those high-value products, last summer Heliae transitioned its business to encompass agroscience and animal feed as well as nutraceuticals.

The company still has an interest in the algae biofuel angle, too. Its website features an article from the American Ceramic Society titled “Glass-Grown Algae May Be The Future of Biofuel,” featuring a detailed rundown of Schott’s glass tubing.

Considering the source, it’s not surprising that the article makes the case for photobioreactors:

…closed systems allow close monitoring and control of the creatures themselves and their environment—nutrient levels, temperature, pH, carbon dioxide levels, sunlight, etc—making it easier to prevent contamination and optimize growth of the algae themselves.

And specifically, photobioreactors made from glass tubing:

…at the beginning of its lifetime, glass transmits 10–15% more light than other materials. And in regards to how much light transmissibility changes with sunlight, glass also has an advantage—while other materials’ transmission can be reduced (by as much as 80%, depending on the material) by UV light, glass retains its transmissibility.

Glass is also more durable (the oldest glass tubing that Schott has is almost 50 years old now), food and pharma grade, biosecure, and resistant to mechanical and chemical scratches, an important consideration considering that algae-filled tubing must be cleaned with chemicals, brushes, or such.

However, the article also passingly notes that the algae biofuel R&D field is wide open.

One key area on our radar is the use of flexible, floating plastic photobioreactors, and last year the Energy Department unloaded a cool $25 million in funding for advanced algae biofuel research.

As for cost effectiveness, our sister site Gas2.org has noted that combining algae biofuel systems with municipal wastewater treatment could provide the kind of two-for-one deal that results in lower costs for both wastewater treatment and fuel production.

In addition, as the Navy’s interest in biofuel demonstrates, energy security is driving federal policy in the direction of locally sourced renewable fuels, and algae biofuel fits the bill nicely.

Not for nothing, but a couple of years ago we noticed that ExxonMobil was dabbling in algae biofuel, only to drop it like a hot potato. Perhaps they should rethink that.

Stay tuned.

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Photo Credit (cropped and enhanced): Photobioreactors courtesy of Schott.









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