Electron microscope image of oil shale (Photo courtesy of Kalpana Katti)
The United States has massive deposits of petroleum locked in shale. Government estimates are there are two trillion barrels of oil, and perhaps 800 billion barrels could be recovered. That’s about three times the oil reserves of Saudi Arabia.
The problem is finding an efficient way to get that petroleum out of the rock. It’s a challenge that’s frustrated scientists for decades.
Two North Dakota State University researchers are taking a different approach to the problem, and they believe the key to extracting oil from shale is in understanding the material at the nano scale.
Nano is breaking materials down to the molecular level and manipulating those tiny building blocks. Many nano materials are being studied and developed, but nature also creates nano materials.
Oil shale isn’t really oil or shale. The rock is made up of very hard minerals like quartz and it contains a waxy organic substance called kerogen. The kerogen will naturally turn into oil after millions of years of exposure to heat and pressure in the earth.
If the kerogen can be extracted from the rock it can be refined into crude oil. Most efforts to extract kerogen involve heating the rock until the kerogen vaporizes. The problem is that process uses more energy than is recovers.
Oil shale sample from 500 feet below the surface (Courtesy of Kalpana Katti)
The husband wife team of Kalpana and Dinesh Katti are taking a different approach.
Dinesh Katti is a civil engineering professor at NDSU who works with molecular computer modeling.
Kalpana Katti is a distinguished professor in the Civil Engineering Department who studies nano scale materials. She essentially takes things apart and rebuilds them at the molecular level. A couple of years ago she started looking at oil shale and discovered the kerogen in the rock is nano sized. At 10 to 20 nanometers it’s a little smaller than a virus.
“Nanometer kerogen was a huge surprise, said Kalpana Katti. “That was not in the scientific literature, that was a very wow moment.”
“That changes the whole thing,” adds Dinesh Katti.
And here’s why. Researchers are increasingly understanding that at the nano scale, materials have different properties.
In the case of oil shale, it means the nanoscale kerogen bonds with the minerals in the rock. That’s why it’s so difficult to remove.
The Kattis discovered different characteristics in different locations on the kerogen molecules. It’s like a ball with velcro in one spot, a magnet in another. Different things will stick to each spot. So each Kerogen molecule could have attraction to nearly a dozen different minerals.
“If we can get a good understanding of the energy connection between the kerogen and the minerals, we might be able to get in between with some other molecules,” said Dinesh Katti.
The Kattis plan to use computer modeling to find the best way to break the bonds between kerogen and minerals, freeing the petroleum from the rock.
They say the solution needs to be cost effective and environmentally friendly. It could be an enzyme, or a chemical, or a combination.
Dinesh Katti offers an over simplified analogy. “If you have a pan with food dried on it’s very difficult to clean. But soak it in water and the dried food is easily removed.”
The next big step is looking to pharmaceutical and biomedical research for molecules that might break the bonds between kerogen and minerals.
They’ll run computer simulations to identify the best options, and test those in the lab.
Kalpana Katti said it won’t be easy or quick because of the complex interactions happening at the nano scale.
Their research hasn’t received much funding, just a $150,000 Department of Energy seed grant that helped buy some new lab equipment.
But Dinesh and Kalpana Katti both say they are very confident the nano scale is the right place to solve a problem that has stymied researchers for decades.
“Of course you never a guarantee a solution will happen, but based on what we have learned I have a high degree of optimism,” Dinesh Katti said. “We might find the best way, or maybe somebody else will use our research to find the answer.”