Science

Algae to crude oil: Million-year natural process takes minutes in the lab

Algae to crude oil: Million-ye...
Biocrude produced using the new process
Biocrude produced using the new process
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The algae slurry that starts the process can be up to 80 percent water
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The algae slurry that starts the process can be up to 80 percent water
Biocrude produced using the new process
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Biocrude produced using the new process
Steps in the process for making fuel from algae – the algae slurry, crude oil, and refined diesel fuel
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Steps in the process for making fuel from algae – the algae slurry, crude oil, and refined diesel fuel
This muck may fuel your car in the future
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This muck may fuel your car in the future
PNNL lab manager Tom Hart, pouring some of the unprocessed algae
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PNNL lab manager Tom Hart, pouring some of the unprocessed algae

Engineers at the US Department of Energy’s Pacific Northwest National Laboratory (PNNL) have created a continuous process that produces useful crude oil minutes after harvested algae is introduced. This new process does not require drying out the algae, which grows in water, saving time and energy that would be otherwise wasted. The final product can be refined into aviation fuel, diesel, or gasoline.

The process mimics some of the conditions that originally turned prehistoric plant material into fossil fuel deep within the earth – high pressures and temperatures.

Algae, an aquatic plant, has long been considered as a biofuel source, but the steps needed to turn a wet, green plant into clear, burnable fuel have been both expensive and time-consuming. The algae had to be processed in a series of steps, one of which involved drying it out and removing all the water, which might be 80 percent of the biomass. Then solvents were used to extract energy-rich hydrocarbons from the dried material.

The PNNL team created a continuous process that starts with the wet algae and subjects the entire mass – water, algae, and all – to high temperatures and pressures, in this case, 350ºC (662ºF) and 3,000 psi.

"It's a bit like using a pressure cooker, only the pressures and temperatures we use are much higher," said Laboratory Fellow Douglas Elliott, the leader of the research team. "In a sense, we are duplicating the process in the earth that converted algae into oil over the course of millions of years. We're just doing it much, much faster."

Steps in the process for making fuel from algae – the algae slurry, crude oil, and refined diesel fuel
Steps in the process for making fuel from algae – the algae slurry, crude oil, and refined diesel fuel

The products of the process include crude oil, which can be further refined into aviation fuel, gasoline, or diesel fuel (in tests, the process achieved between 50 and 70 percent conversion of the algae’s carbon into fuel); clean water, which can be used to grow more algae; fuel gas, which can be burned to make electricity or cleaned to make natural gas; and nutrients like nitrogen, phosphorus, and potassium – needed for growing algae.

Genifuel Corporation has licensed the process, and has been working with the team at the lab since 2008. The company intends to team with some industrial partners to create a pilot plant using this process to make biofuel in industrial quantities.

The process was detailed in a recent paper published in the journal Algal Research. More information on the technology is available in the video below.

Source: PNNL

Algae to Bio-Crude in Less Than 60 Minutes

53 comments
Elmar Moelzer
With the temperatures and pressures involved, the question is how energy efficient this process is. The whole biofuel process is pretty hard to get net energy positive to begin with. Algae are pretty good compared to others, but I still have my doubts.
Rt1583
A nice story. Unfortunately it is meaningless without knowing what the efficiency of the process is.
dabel8
Current refining have temperatures reaching 600 degrees C so the temperatures for this process are fairly moderate. There's a huge potential to improve the efficiency in the refining process as the algae can be tailored to create a specific 'crude oil' for a final product (gas, kerosene, diesel etc)
Slowburn
What happens if you add grass clipping into the mix? ................................................................................. So this could mean that the timeline for producing natural oil can easily fit into a 6000 year time frame.
Slowburn
It should be possible to capture a fair amount of the heat energy when cooling the mixture.
Ikeleaka Kaluva
Yeah thats great. Now if they take all the bio mass know as human waste and shove that into the dry oil wells along with water they can produce algae again the old school way and maybe the owner of all those old wells can strrike it rich again.
Buellrider
So if scientists find a cheap means of making fuel that contributes to the C02 problem and it drys up funding toward developing viable non polluting means of transportation then we are all screwed. Oil companies already try to get everyone believing that oil can't be replaced so they'll make sure that this algae thing is bought and buried.
William Bodin
Is everyone missing the elephant in the room? OPEC? Every nation on earth no matter how big or small or how many natural resources it has or what type - will be able to make their own oil. As much of it as they want. States that make their living solely on the sale of oil are going to be in deep doo-doo. Economic and geo-political realignment of EPIC proportions comin up!
Bob
Hmmm. In a sunny region how about pumping the algae through a high pressure pipeline surrounded by focused curved mirrors to increase the solar heating? It may be possible to increase the pressure and/or time. Perhaps an inexpensive catalyst could be found to speed up the reaction. Centrifuging the algae as it entered the the system would be a cheap method of removing a large percentage of the water before reacting. Or, setting up something like this next to an electric power plant using the waste heat and cooling lake water to process and grow more algae would be another possibility. Use the CO2 from the plant to speed up the growth of the algae. Just a few random thoughts.
Gildas Dubois
To Rt1583; That's proprietary info... Good luck getting a real number for any process form any manufacturer! But seriously, getting this temp and pressure range, especially if the product is in an emulsion, is no big deal. Well within the range of adiabatic processes, especially if multi-stage. The part I'm really stumped by is how they keep the liquid at a set temperature/pressure for an hour