It looks like Mother Nature was wasting her time with a multimillion-year process to produce crude oil. Michigan Engineering researchers can "pressure-cook" algae for as little as a minute and transform an unprecedented 65 percent of the green slime into biocrude.
"We're trying to mimic the process in nature that forms crude oil with marine organisms," said Phil Savage, an Arthur F. Thurnau professor and a professor of chemical engineering at the University of Michigan.
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.
Previously, Savage and his team heated the algae for times ranging from 10 to 90 minutes. They saw their best results, with about half of the algae converted to biocrude, after treating it for 10 to 40 minutes at 570 degrees. Why are the one-minute results so much better? Savage and Faeth won't be sure until they have done more experiments, but they have some ideas.
"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.
"For example, the biocrude might decompose into substances that dissolve in water, and the fast heating rates might discourage that reaction," Faeth said.