(326b) Ethane Oxidative Dehydrogenation in Microwave-Heated Fixed Bed and Structured Catalyst Reactors

Light olefins, including propylene and ethylene, are extensively used as chemical building blocks. The demand for light olefins has been growing and expected to continue. Steam cracking of naphtha has traditionally been the most common method for light olefins production. However, the intensive energy demand of the process and severe coking and the abundance of shale gas have changed the feedstock in the US. Specifically, catalytic dehydrogenation of light alkanes obtained from shale gas has attracted attention. Yet, this is a highly endothermic and high temperature reaction. Microwave heating is energy-efficient, rapid and selective and can lead to process intensification for modular and distributed ethylene production.

In this talk, we will present ethane oxidative dehydrogenation with carbon dioxide over Ga₂O₃/Al₂O₃ catalyst to provide insights into microwave reactor design. Our results showed that the heating rate with microwaves increases at least 10 times compared to conventional heating. Next, we compare the performance of fixed beds and structured beds of different characteristic features. The temperature uniformity is enhanced in the structured bed due to increased heat transfer. IR thermal camera shows a standard deviation in the temperature distribution of 5.0 °C in the structured bed and of 12 °C in the fixed bed. The structured bed is more stable as the reactivity dropped only 4% after 2 hr of reaction vs. 18% in the case of a fixed bed. Lastly, we will compare a merit index of microwave and conventional heating reactors to assess the potential of microwave technology for light olefins production.