(326a) Low-Temperature Chemical Looping Oxidative Dehydrogenation of Ethane for Modular Ethane to Liquids

Of the natural gas liquids, ethane poses particular transport challenges for producers. The concentrations of ethane in wet-gas can exceed natural gas pipeline specifications; it is not easily liquefied for transport; and dedicated ethane pipeline capacity is limited. A modular scale process that can convert ethane into valuable, easily-transported liquids at gas processing facilities can capture significant value from this domestic resource. However, selective ethane conversion at modular scales is difficult; steam cracking to ethylene (the traditional industrial approach) requires very high temperatures (>1000 °C), and typical oxidative dehydrogenation approaches require energy intensive air separation and precise reactor control. Here we present a modular ethane-to-liquid fuel (m-ETL) system. This system is enabled by low-temperature (≤750 °C) redox-catalysts for the chemical-looping oxidative dehydrogenation of ethane (CL-ODH). In this approach, ethane is partially oxidized to ethylene and water with the lattice oxygen of the redox catalyst in a packed bed reactor. After the redox catalyst is depleted of oxygen, valve switching is used to introduce air to regenerate the lattice oxygen and provide heat for the net reaction. By bundling multiple packed beds together in parallel, heat can be integrated between reaction steps. The low-temperature parallel packed bed approach makes it well suited for modular implementations. The ability to use number-up manufacturing for the CL-ODH bundles, and the modular scale of the bundles make them well suited for low-cost distributed implementation. In the m- ETL system, the resulting ethylene rich product stream from the CL-ODH reactor would then be compressed and oligomerized to light liquid olefins suitable for use as gasoline. Gaseous hydrocarbon byproducts are then recycled with a slip stream burned in an engine to provide power for the system. Experimental CL-ODH redox catalyst is presented along with process and economic modeling studies.