A University of Hawaiʻi at Mānoa College of Engineering project that may potentially enhance the performance and efficiency of petroleum-related industrial processes received a major boost from the American Chemical Society. The $110,000 Doctoral New Investigator grant from the society’s petroleum research fund will help support the work of two PhD students for Assistant Professor William Uspal’s project, “Catalytically Active Colloidal Suspensions: from Single Particle to Bulk Behavior.”
Catalytically active particles
Catalytically active microparticles and nanoparticles are frequently encountered in petroleum-related technological and natural settings. A catalytically active particle provides a site for chemical reactions to occur involving molecules dissolved in the surrounding liquid. In a phenomenon called “phoresis,” chemical energy released in the catalytic reaction can be transformed into mechanical energy of the particle.
Due to phoretic motion, a suspension of catalytically active particles dissolved in water can exhibit novel properties, such as vanishing viscosity, or migration of the particles over long distances. In recent years, there has been growing interest in designing chemically active “micromotors” and “nanomotors” that self-propel in liquid through phoresis.
Uspal’s project aims to understand how suspensions of catalytically active particles behave in the complex conditions characteristic of petroleum reservoirs and petroleum-related processes. For instance, in a process called “enhanced oil recovery,” a specially formulated fluid is injected into an oil well in order to drive out oil droplets trapped within the reservoir.
Catalytic particles can be used in injection fluids in order to convert heavy oil into lighter oil within the reservoir, enhancing the mobility of the droplets. However, in this process, the catalytic particles will exhibit phoretic motion while confined within the tight spaces of porous rock. To date, the role of phoresis in this process has been largely overlooked, although it could potentially be harnessed to substantially enhance oil recovery.
“Within an oil reservoir, catalytic particles can put themselves and the surrounding fluid into motion by tapping into the chemical energy of the trapped oil,” Uspal said. “By acting as micromotors or nanomotors and stirring the fluid, they might assist recovery of the oil. Potentially, one could even design catalytic particles that navigate towards oil droplets by following chemical gradients.”
Uspal’s team will use computer modeling to understand the microscopic behavior of catalytic particles in complex conditions and predict macroscopic material properties like viscosity. The results of this research will contribute to the fundamental understanding of “active fluids,” and potentially enhance the performance and efficiency of petroleum-related industrial processes.