Fast Food for an Energy-Hungry Economy

Phil Savage, an Arthur F. Thurnau professor and a professor of chemical engineering at the University of Michigan, with Julia Faeth, a doctoral student in Savage’s University of Michigan laboratory, have unveiled a fast-cooking process that converts 65-percent of wet algae feedstock into biocrude in one minute.

Considering that nature takes millennia to convert ancient flora and fauna into the raw materials of our energy economy, this decidedly quicker process might capture even the shortest of attention spans.

The team investigated the hydrothermal liquefaction (HTL) of wet Nannochloropsis species algae, something like pressure cooking your vegetables, for a mere minute. This was enough to create a form of at least a biofuel precursor. The video exposes Dr. Savage’s skeptical view of electrical aircraft.

As the University’s news item explains, “An hydrothermal process is one that involves water at elevated temperatures and pressures; hydrothermal liquefaction (HTL) is one of a number of methods for converting biomass conversion to biofuels or biofuel precursors. HTL avoids energy-intensive drying steps, and is thus more energy efficient for biomass with very high moisture content—such as microalgae—the researchers note.”

Savage and Faeth, “Filled a steel pipe connector with 1.5 milliliters of wet algae, capped it and plunged it into 1,100-degree Fahrenheit sand” for the quick-cooking process.

Previous efforts brewed the algae for 10 to 90 minutes, with optimum outputs (about 50-percent conversion) after 10 to 40 minutes at 570 degrees. Improvements for minute crude suggest that reactions are quicker than previously thought, and the quickness reduces unwanted reactions.

Researchers note that the small size of the gear reduces costs (and also output, one may assume) and the wetness of the overall process avoids the long drying and oil extraction that makes algae-based fuel a high-priced endeavor.

The wet method breaks down proteins and carbohydrates, leaving crude with 90-percent of the energy in the original algae—“near the upper bound of what is possible, according to Savage.”

Not resting on their already impressive accomplishment, the team has produced a biocrude that was 97-percent carbon and hydrogen.  A paper is now going through peer review.

The University reports funding, “By the Emerging Frontiers in Research and Innovation program of the National Science Foundation. The university is pursuing patent protection for the intellectual property, and is seeking commercialization partners to help bring the technology to market.”

Dr. Savage provides hope for the future. “Once producing biofuel from algae is economical, researchers estimate that an area the size of New Mexico could provide enough oil to match current U.S. petroleum consumption. And, unlike corn produced for ethanol—which already accounts for half that area—the algae won’t need to occupy good farmland, thriving in brackish ponds instead.”

Savage and Faeth presented their results at the 2012 American Institute of Chemical Engineers (AIChE) Annual Meeting in Pittsburgh in their paper, “The Effects of Heating Rate and Reaction Time On Hydrothermal Liquefaction of Microalgae. AIChE 2012”

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