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Turning Pig Crap into Crude Oil

Scientists have pioneered a new process for converting pig manure into crude oil.

Chemists at the National Institute of Standards and Technology have completed the first full chemical analysis of the processing needed to transform pig manure into fuel for vehicles or heating. The feasibility of large scale production remains riddled with question marks, but the science is feasible.

“Pig manure crude will require a lot of refining,” according to a NIST paper.

The oil used in the NIST analyses was provided by engineer Yuanhui Zhang of the University of Illinois Urbana-Champaign. Zhang developed a system using heat and pressure to transform organic compounds such as manure into oil.

The pig manure crude contains at least 83 major compounds, including many components that would need to be removed, such as about 15 percent water by volume, sulfur that otherwise could end up as pollution in vehicle exhaust, and lots of char waste containing heavy metals, including iron, zinc, silver, cobalt, chromium, lanthanum, scandium, tungsten and minute amounts of gold and hafnium.

“The fact that pig manure crude oil contains a lot of water is unfavorable,” said Tom Bruno, an NIST chemist and one of the principal researchers. “They would need to get the water out.”

The NIST team used an advanced distillation curve, which provides highly detailed and accurate data on the makeup and performance of complex fluids, to conduct the analysis. A distillation curve charts the percentage of the total mixture that evaporates as a sample is slowly heated. Because various components of a complex mixture usually have different boiling points, a distillation curve provides a good measure of the relative amount of each component in the mixture.

NIST researchers analyzed the graphite-like char remaining after the distillation by bombarding it with neutrons, a non-destructive way of identifying the types and amounts of elements present. Two complementary neutron methods detected the heavy metals listed above.