2024 AIChE Annual Meeting
(499f) A Photothermal Reactor with a Selective Solar Absorber to Produce Liquid Fuels Via Ethylene Oligomerization
Authors
Aitbekova, A. - Presenter, Stanford University
Su, M., California Institute of Technology
Salazar, M., California Institute of Technology
Atwater, H., California Institute of Technology
Utilizing solar thermal energy for thermochemical processes has attracted substantial recent interest due to its capacity to provide a sustainable alternative for the synthesis of fuels, chemicals, and materials compared to traditional industrial methods. Furthermore, thermocatalytic processes allow operation at reduced temperatures and pressures achievable with direct solar-to-thermal energy conversion alone. Here, we present a scalable photothermal reactor to exploit a selective solar absorber that converts sunlight into thermal energy for sustainable fuel synthesis. We report a selective solar absorber consisting of an anti-reflective coating and an optically transparent metal layer, achieving a calculated maximum temperature of 249 °C under one sun illumination and 125 °C under ambient operating conditions (25 °C, 1 atm). The photothermal reactor was employed in batch and flow operation using homogenous and heterogenous Ni-catalyzed ethylene oligomerization reactions. In batch operation, homogenous oligomerization yielded C6 – C24 hydrocarbon products, and in flow operation, heterogenous oligomerization yielded 25 % ethylene conversion to butene and hexene products. Finally, we present simulated results for a large-scale photothermal reactor, which predict spatially uniform maximum potential temperatures up to 120 °C and 210 °C under one and three sun illumination, respectively, demonstrating the potential of this system for generating fuels from sunlight using scalable devices.