Nov 7 2018
When mixed with a nanosized catalyst, a whiff of plasma can make chemical reactions to continue faster, more selectively, either at lower temperatures or at lower voltages than without plasma—a phenomenon that is not exactly known.
Now, with the help of computer modeling, Juliusz Kruszelnicki from the University of Michigan studied the interactions between plasmas and metal catalysts that were integrated into ceramic beads in a closely packed bed reactor and found that the beads, metals, and gas all work together to generate plasma that not only intensifies the electric fields but also locally heats the catalyst, which can subsequently speed up the reactions.
Kruszelnicki will discuss the results of the study at the American Physical Society 71st Annual Gaseous Electronics Conference and 60th Annual meeting of the APS Division of Plasma Physics, which is taking place at the Oregon Convention Center in Portland from November 5th to 9th, 2018.
Through these plasma reactors, valuable chemical processes can possibly be made more economical and efficient, for example, changing carbon dioxide into fuels, removing air pollution, and creating ammonia for fertilizer, via “plasma chemical conversion.”
Combining thermocatalytic systems and plasmas allows new avenues to produce chemical products you otherwise might not be able to, or perhaps to do so at higher efficiency.
Juliusz Kruszelnicki, University of Michigan.
Using sophisticated multiphysics codes developed in the laboratory of Mark J. Kushner at the University of Michigan, Kruszelnicki successfully modeled the interactions of catalysts and plasma. These comprise of modules for phenomena, for example, chemical kinetics, fluid dynamics, electromagnetics, and surface chemistry. Kruszelnicki developed a packed bed reactor, which is actually a tube containing ceramic beads, with electricity passing via concentric electrodes. Catalysts cause the gases moving through the reactor to react in certain ways, for example, combining hydrogen and nitrogen to produce ammonia.
Kruszelnicki discovered that field emission of electrons occurs when the beads are integrated with metallic catalyst particles and subsequently electrified. This field emission of electrons allows for higher plasma densities. The catalyst heated up by the plasma can cause the chemical reaction to continue more efficiently and more quickly, possibly reducing the applied power required for the reaction.
Through this process of localizing the electric field, electrons can be emitted from the surface of the metal particles and start a plasma, where it otherwise wouldn’t occur.
Juliusz Kruszelnicki, University of Michigan.
By replicating low-temperature plasma chemistry, Kruszelnicki along with other members of the Kushner lab is identifying novel ways in which both plasma and catalysts can work together and render plasma chemical conversion more efficient than conventional chemical conversion.
At present, the investigators are working with the Industry-University Cooperative Research Centers Program of National Science Foundation to team up with companies to translate this work for use in industry. They also believe that these more efficient processes will be used with off-the-grid applications, for example, developing fertilizers for subsistence farmers with the help of solar power.