The National Energy Technology Laboratory (NETL) is pioneering an effort to better understand and utilize the application of microwave (MW) fields to various chemical reactions and materials processes. The potential cost benefits and energy efficiency of MW-enhanced processes have yet to be fully explored and quantified. Research on the application of MW fields to chemical processes for enhanced conversion and selectivity has received significantly increased interest in recent years. The benefits of MW application to reaction systems include rapid, selective heating of the catalyst surface and reacting species to promote conversion to desired products at significantly lower, bulk system temperatures. Additional microwave-specific effects are also being explored. The interactions of materials with both the electric and magnetic components of the MW field are being examined using impedance analyzers, vector network analyzers (VNA), and magnetometry. Two microwave reactor systems have been designed and built in NETL’s state-of-the-art REACT Facility: a 2 kW fixed frequency, fixed-bed flow reactor; and, a one-of-a-kind 500 W variable frequency reactor. Techniques are being developed to utilize the VNA with these systems to characterize the materials <i>in-situ</i> to examine the effects of temperature, MW power and frequency, and other reaction conditions on the MW activity of the catalysts.  In present studies, different heterogeneous catalytic reactions are being examined with and without the addition of a MW field. The reactions include Fischer-Tropsch (FT) synthesis, an overall exothermic reaction, and methane dehydroaromatization (MDHA), an endothermic reaction. Additionally, MW-assisted coal pyrolysis has been extensively studied. Conventional catalysts and conditions for these reactions were examined first, and the MW parameters varied include power and pulse time. Catalyst and support materials were characterized, including their dielectric properties, to identify ways to modify the materials to enhance interaction with the MW field. This information, along with the MW field modeling effort NETL is conducting, will be used to design novel microwave-active catalyst materials and systems.

Microwave-assisted processes for chemical and fuel conversion

255th National Meeting (2018)

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