New molecule could be used in extracting oil
New Haven, Conn. A Yale research team has succeeded for the first time in turning supercritical carbon dioxide, which is CO2 under tremendous pressure, into gel form.
The discovery could have widespread application in a number of industries, including oil drilling, in which the gel form of CO2 would be used instead of water to extract oil from the ground. The new process might be less expensive and much more environmentally friendly.
"The chemical and oil industries use hundreds of millions of gallons of organic solvents in their processes and their disposal creates an environmental problem," said Andrew Hamilton, Irenee duPont Professor of Chemistry. "Supercritical CO2 could replace some of these solvents."
The study published in the November 19 issue of Science was a collaboration between Hamilton and his team at Yale researchers Andrew Carr and R.E. Melandez and scientists at the University of Pittsburgh, among them Professors Robert Enick and Eric Beckman.
Hamilton said the scientists set out with the challenge of designing synthetic molecules to increase the viscosity of supercritical CO2. The research was funded by the U.S. Department of Energy.
"We were almost too successful," he said. "We discovered a molecule that gelled supercritical CO2. Then we had another surprise. When we released the pressure the CO2 evaporated from this gel and left behind a solid material made up of interconnected networks of our designed molecules, and it had extremely low density."
The benefit of using the new solvent in oil recovery is that, once the oil is extracted, the supercritical CO2 would be disposed of through evaporation or recycling, greatly reducing the cost of the extraction and protecting the environment, Hamilton said.
He said the next step is to improve the viscosity-enhancing properties of the molecules and simplify the structure so that it can be produced in bulk.
"People see supercritical CO2 as a more benign solvent for the next century," Hamilton said.
Science