Cooking Biocrude in One Minute

Researchers at the University of Michigan have discovered a pressure-cooker system that can convert algae into 65% biocrude in only one minute.

The team, led by chemical engineering Prof. Phil Savage, reported its results yesterday in Pittsburgh during the annual meeting of the American Institute of Chemical Engineers.

The scientists achieved the record-high production ratio by sealing a small sample of a marine green microalgae (Nannochloropsis) in a steel tube and immersing it for 60 seconds in sand heated to 1,100 F.

In previous tests, the team's best result was a 50% conversion after heating samples for 10-40 minutes at 570 F. The group notes that faster reaction times and higher yield rates suggest that the process could be commercialized using relatively small reactors.

The Univ. of Mich. researchers say more experiments may explain why shorter cooking at higher temperature produces a better yield. They speculate that the reactions that produce biocrude may occur faster than previously thought. They also theorize that higher temperatures may prevent the biocrude from decomposing.

Current algae-based biofuel production involves drying algae and extracting its natural oil a process that makes fuel costing more than $20 per gallon, the researchers note. They caution that it's too soon to tell if their pressure-cooker process would be more cost effective.

The team notes that biocrude must be "pre-refined" to strip away their oxygen and nitrogen content. Savage's laboratory has separately developed a technique to make biofuel 97% pure and expects to publish a paper on that process soon.