Applications of thermal plasma flow, energy and particle nucleation fields control in the materials and energy sectors

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This research program is on the development of technologies based on "thermal plasmas" consisting of ionized gases at extreme temperatures reaching 10,000 C and close to atmospheric pressure. Thermal plasma devices are used and modeled in the present program for generating carbon-based nano-structures such as graphene nanoflakes (GNF). The GNF are in the shape of 2-dimensional sheet-like materials having a small number of atomic layers, these being generated in our reactors from the atomic level through particle nucleation occurring between 4,400 C and 5,200 C. A particular emphasis of the research program is in the development of control strategies within the synthesis reactors that will enable three specific areas of applications opening new opportunities in the energy sector, the environment, and advanced materials. Thermal plasma reactor design are studied in terms of the plasma flow and temperature fields, as well as particle nucleation mapping occurring within the reactor and the chemical species being generated. A particular focus is made on the control of the plasma flow expansion. This control provides, as a 1st application, the possibility to use the "active" chemical species generated in the plasma to add chemical functionalities on powders and surfaces while maintaining the surfaces relatively cold and at atmospheric pressure. Examples of this 1st application would be to make fully wettable (hydrophillic) or fully non-wettable (hydrophobic) surfaces (wood or particles for example) at rapid industrial scales. A 2nd application of the flow control is in the energy and environment sector, focusing particularly on the 292 northern Canadian communities using diesel-based electrical power independent from the electrical distribution grid system. These power generators produce a large amount of greenhouse gases (GHG) but also an important loss of electrical energy due to their poor on/off capabilities for adjusting to the energy demand. The plasma systems developed uses a GHG (methane) for generating the carbon-based particles, and hydrogen as a by-product. Hydrogen can thus act as a means of storage of the excess electrical energy generated, and then further used to provide electricity through fuel cell based systems. This program targets the design of a plasma reactor that will optimize hydrogen production while maintaining the high added value carbon powder production, and eliminating a GHG. A 3rd application of the plasma flow control relates to plasma spraying applications for producing advanced coatings particularly for the aeronautics sector. A constant problem in plasma spraying is controlling the thermal history of the particles injected in the very turbulent plasma flow. We apply here our control strategies based on plasma expansion to generate more uniform flow patterns and increase the efficiency of plasma spraying processes.