A glance at the algal biofuel process

Jalal Rastegary working on the algal biofuel project

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In a recent report on his work, Jalal Rastegary presents the potential of algal biofuel, its drawbacks and risks, basic economics and benefits, processing and utilization requirement, waste and byproducts, environmental impacts, as well as infrastructure requirements. He writes, “In order to continue human development in a sound manner, all options in managing atmospheric greenhouse gases, including various ways to produce, consume, and deal with it, as well as a new renewable source of energy must be considered. We must be willing to face the reality and search in earnest for alternative energy solutions.”Dr. Abbas Ghassemi, professor and director of the Institute for Energy & the Environment at New Mexico State University, also contributed to the work. Here, Rastegary provides an overview of the algal biofuel process, and even sheds some light on the healthful possibilities of algae production.

IEE: In a recent paper, you mentioned algae can be grown in an open pond or a closed photobioreactor. What is a closed photobioreactor?
Rastegary: A photobioreactor is a closed system which provides a controlled environment and enables high productivity of algae. All growth requirements of algae are introduced to the photobioreactor system. These include CO2 supply, water, optimal temperature, efficient exposure to light, and culture density, etc. They can be different types, shapes and materials. There are many different kinds of photobioreactors. If you search online, you can find a lot of different, innovative styles. Some of them are even patented.

IEE: Downstairs, in the IEE Algae lab, could the flasks [in which algae is being grown] be considered bioreactors?
Rastegary: We have some larger flasks which can be photo reactors, yes.

IEE: In the biofuel production process what is the next step after growing the algae? You grow it and then…?
Rastegary: Harvesting and dewatering. There are different techniques for harvesting microalgae such as filtration, which is the most common method, centrifugation (which works using the sedimentation principle), and flocculation. Flocculation is a method of separation using chemicals to force the algae to form lumps.

“It has to be a basket of biofuels—not only algae.” -Rastegary, Research Scientist, IEE

IEE: What do they [researchers, commercial facilities] do after they have de-watered it?
Rastegary: Then it’s the process of getting the oil from the algae. There are different methods of oil extraction: chemical and mechanical. The simplest one would be a similar process to the one used for crops like soybeans, corn…that process can be used for getting the oil out of algae as well.

IEE: And that’s called the biofuel recovery process?
Rastegary: For algae, it is called biodiesel, or biofuel. So the product of that process is biofuel. The oil is extracted, which also creates some byproducts that can be used for other purposes also. Like the byproduct called algae cake. A lot of the byproduct from the recovery process can be used for fertilizer. In fact, algae is very high in omega 3, and some are using algae for that purpose—to extract omega 3 from algae also.

IEE: Can algae be used for those at the same time? Can you simultaneously pull out fertilizer and fuel and omega 3 from algae?
Rastegary: Yes, you can separate the different products. It is a very valuable product when you have algae. Already, they are making a lot of pills from algae. A lot of people think that omega 3 comes from fish, right? This isn’t true. It comes from algae. So when they [the fish] eat algae they get omega 3 and you can get omega 3 from fish. But if you get it directly from algae, it has more omega 3 and better quality. So there are pills available from algae that have omega 3.

IEE: Once the biofuel is recovered can it go straight into a gas tank?
Rastegary: There is some processing it has to go through before it can be used. There are some claims that, with small modifications, it can be used for biofuel. But most the processes are confidential for the companies that use those— most won’t say exactly what process they use to make the best quality biofuel. From what I know, you can use the oil straight as biofuel. So it doesn’t have to really go through a lot of additional processing. It’s simple, it doesn’t have to be very complicated, and it doesn’t have to go through a lot of machinery. It’s relatively easy to convert into fuel. Once you have the oil you can easily transfer it and make fuel out of it.

IEE: Does it involve any chemicals? Like, what kind of waste do you see coming out of this process?
Rastegary: This process shouldn’t have much waste. Algae is really a very clean biofuel. Most of the oil we get comes from algae. It’s been sitting there for millions of years and in the last 200, 300 years we are using all of it. So, really, fossil fuels are also coming from algae. It was just a long process. It has taken millions of years before it changed to oil—and now we are using them. Algae, we can use it and grow it in days. And to convert the algae into oil, it is a very short process. The only problem with algae at this time is that it is not commercialized. It is not cost efficient at this point. So people are working to make it cost efficient. But it’s good to know that the oil we already use also comes from algae.

“It’s not going to be a few months but we hope that in the next 10-15 years we will have algal biofuel.” -Rastegary, Research Scientist, IEE

IEE: Why use algae biofuel over other fuel? What are the benefits of using algal biofuel?
Rastegary: Biofuel from algae has many advantages over fossil fuel as well as other biofuels. Algal fuel is carbon neutral. It can use saline-brackish water and can be grown in a wasteland. In addition, algae produce 30 to 100 times more oil per acre than oil crops, such as corn or soybeans. Also, most other biofuels are from food crops whereas algae is not, which can solve the food-versus-fuel problem. Micro algae biofuel is highly biodegradable and biofuel from algae contains no sulfur, and therefore, it is non-toxic.

IEE: Could you give us a sense of the timeline of the biofuel process? From research to industry, how long before we go from seeing algae in the lab to seeing algae in our gas pumps?
Rastegary: The U.S. Department of Energy started research on algae in 1978. There has been a lot of research and there are quite a few policies behind biofuel research. At this time, algal biofuel is costly because there is no prepared infrastructure. Once a continuous process is in place, we have continuous growth, continuous harvesting, continuous processing—when we get to that point, everything is going to be very smooth and easy to do. But at this time it’s mostly research, not all of the problems have been solved. It’s going to take time, effort, investments…There are many factors involved in biofuel development. I cannot say that we are going to be using it in the near future.

In a practical sense, biofuel can be developed in not a long time, but price wise—which is actually everything, depending on the cost and benefits—the cost is high. It depends on different aspects such as public awareness, public readiness, our government, the officials, prepared laws and regulations. The public and government understand the need for biofuel. It’s not going to be a few months but we hope that in the next 10-15 years we will have algal biofuel.

In the long run, we have no other choices. We need renewable clean energy that can come from something other than fossil fuels. It has to be a basket of biofuels—not only algae. It’s going to come from wind, it’s going to be solar, it’s going to be different biomasses. Algae is going to be one biomass that can really be used as a biofuel.


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