Extracting oil, with heat
With a material as simple as salt, engineering physics scientists and students are testing ways to store and transport heat for applications as diverse as storing solar energy and extracting oil. Their expertise is useful for oil companies such as Shell, which someday could use the powerful heat-transferring properties of molten salt to produce oil and gas from oil shale deposits.
The United States is home to about 60 percent of the world’s deposits of oil shale, a fine-grained sedimentary rock that contains kerogen. For decades, oil companies have tried to find an economically sustainable way to develop oil shale. Historically, these attempts have occurred through mining, an endeavor that includes environmental effects and considerations.
One alternative is to raise the temperature of the oil shale in the field via hot liquid circulated through pipes installed in the field. The heat could release kerogen from the oil shale and enable oil companies to transport it to the surface, much like they do conventional oil and gas.
On a much smaller scale, the technology underlying that system is being tested on campus. With funding from Shell and the U.S. Department of Energy, Engineering Physics Senior Scientist Mark Anderson, Research Professor Kumar Sridharan and Associate Professor Todd Allen and their students have built a molten salt test loop. This unique system enabled the researchers to study such aspects of molten salt as heat transfer, flow-induced corrosion, static corrosion, and system startup. In addition, also with Shell funding, the team has developed an extensive, easily searchable database at allen.neep.wisc.edu/shell. Based on 19 salt properties, including melting and boiling points, corrosion, and thermal conductivity, the database can help researchers choose a salt or salt combination for any application.
Over the past five years, UW-Madison has become a leader in molten salt research, having recently launched collaborations with Albuquerque, Lawrence Livermore, Oak Ridge, Idaho, and Sandia National Laboratories. “We have some of the largest capabilities for working with liquid salts, and part of this was due to the work we did with Shell,” says Anderson.