Biocrude from Algae Breakthrough: Quick Pressure Cook

University of Michigan engineers have devised a quick pressure cooking method of converting algae biomass into biocrude. They are achieving unprecedented yields, according to the researchers.

U.S. researchers say they can do in minutes what Mother Nature needed millions of years to accomplish: turn algae into a source of crude oil.

Scientists at the University of Michigan report they can "pressure-cook" algae for as little as a minute and transform an unprecedented 65 percent of the green slime into biocrude.

...The biocrude created in the "pressure cooker" contained about 90 percent of the energy in the original algae, he said. "That result is near the upper bound of what is possible." _UPI

The researchers speculate that their quick high temperature approach may have hit a "sweet spot" of sorts, allowing just the right reactions, and preventing the unwanted chemical reactions which might decrease biocrude yields.

The findings will be presented Nov. 1 at the 2012 American Institute of Chemical Engineers Annual Meeting in Pittsburgh. Savage's ocean-going organism of choice is the green marine micro-alga of the genus Nannochloropsis. To make their one-minute biocrude, Savage and Julia Faeth, a doctoral student in Savage's lab, filled a steel pipe connector with 1.5 milliliters of wet algae, capped it and plunged it into 1,100-degree Fahrenheit sand. The small volume ensured that the algae was heated through, but with only a minute to warm up, the algae's temperature should have just grazed the 550-degree mark before the team pulled the reactor back out.

..."My guess is that the reactions that produce biocrude are actually must faster than previously thought," Savage said. Faeth suggests that the fast heating might boost the biocrude by keeping unwanted reactions at bay. _PO

The researchers suggest that their quick thermochemical approach is likely to prove more efficient and economical than the traditional methods of drying the algae and extracting the oil. Current costs for algal oil extracted from dried algae exceed $20 a gallon -- not even close to being competitive. Savage and Faeth seem to think they can do much better with their new approach.

Of course, the U. Michigan quick pressure cooking is somewhat similar to other catalytic fast pyrolysis approaches -- including the favourite of Al Fin algal energy analysts, the IH2 approach.

The IH2 process can convert virtually any type of non-food biomass feedstock – including wood, agricultural residues, algae, aquatic plants and solid waste – to a liquid transportation fuel that is interchangeable with crude-oil-derived fuels, and is compatible with current fueling and vehicle infrastructure. According to GTI, the IH2 process differs from other biofuel technologies that produce crude or oxygen-containing intermediates that need substantial upgrading to meet current specifications for transportation fuels. _GTI Pilot IH2 Plant

The challenge for all of these thermochemical biomass to liquid fuels (BTL) approaches is to be able to produce a high quality product in volume at a competitive price.

It is the opinion of most Al Fin algal fuels engineers that high quality algal biocrude will not be able to compete with fuels from cheap natural gas, until cheap process heat from high temperature gas cooled nuclear reactors becomes available.

In the meantime, it is important for this type of research to continue, so that when the proper technological and market ingredients come together, the industrial scale processes will be ready to go.

Advanced biofuels such as this are a good idea, and their time will come. But governments should stay out of the natural competition between fuels and forms of energy, and allow markets to work things out.