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New Technology Turns Algae To Bio-Crude In Less Than An Hour

December 18, 2013
Image Caption: Algae Slurry. Credit: PNNL

[ Watch The Video: Algae To Bio-Crude In Less Than 60 Minutes ]

Brett Smith for redOrbit.com – Your Universe Online

Biofuels scientists have been using algae to generate crude oil for years, but a novel process developed by the Pacific Northwest National Laboratory (PNNL) has the potential to reduce the costs associated with the process, which have been prohibitive thus far.

“Cost is the big roadblock for algae-based fuel,” said Douglas Elliott, the laboratory fellow who led the development of the novel technique. “We believe that the process we’ve created will help make algae biofuels much more economical.”

Naturally-occurring crude oil that is pumped out of the ground is actually based on the decomposition of organic matter like plants and algae. However, the natural process takes millions of years to occur.

In the new PNNL method, algae are exposed to super hot water under high pressure, which converts the biomass into liquid and gas fuels.

“It’s a bit like using a pressure cooker, only the pressures and temperatures we use are much higher,” Elliott said. “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.”

The PNNL team said they were able to improve on the production of crude oil from algae by converting numerous chemical steps into one continuous process. According to the researchers, the most important cost-saving change is the capacity to use wet algae, which is unlike most current processes that demand the algae be dried. The drying process uses a lot of energy and is therefore highly expensive.

“Not having to dry the algae is a big win in this process; that cuts the cost a great deal,” said Elliott. “Then there are bonuses, like being able to extract usable gas from the water and then recycle the remaining water and nutrients to help grow more algae, which further reduces costs.”

Other teams have attempted to use wet algae to create biofuel, but these efforts have typically been conducted one batch at a time. The PNNL system was designed to run continuously, going through about 3.1 pints of algae slurry in the lab reactor per hour. While that may sound unimpressive, the PNNL researchers said their design could easily be scaled up for commercial production. The PNNL system also drops the need for solvents like hexane to extract the energy-rich oils from the rest of the algae.

The PNNL system operates at a temperature of just over 660 degrees F and a pressure of around 3,000 pounds per square inch. Elliott said the novel system was neither easy nor cheap to build – a major drawback to the technology. However, savings on the back end more than compensates for the large investment up front.

According to a PNNL press release, Utah-based Genifuel Corp. has already licensed the new method and is currently working to build a pilot plant.

“This has really been a fruitful collaboration for both Genifuel and PNNL,” said James Oyler, president of Genifuel. “The hydrothermal liquefaction process that PNNL developed for biomass makes the conversion of algae to biofuel much more economical. Genifuel has been a partner to improve the technology and make it feasible for use in a commercial system.”

“It’s a formidable challenge, to make a biofuel that is cost-competitive with established petroleum-based fuels,” Oyler added. “This is a huge step in the right direction.”


Source: Brett Smith for redOrbit.com - Your Universe Online



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