(509o) Kinetic Analysis of 3D-Printed Dual Functional Monoliths in Combined CO2 Capture-Ethane Dehydrogenation to Ethylene

Integrated carbon capture-utilization provides a viable approach to curb anthropogenic CO₂ emissions and, at the same time, produce valuable chemicals and fuels from a waste carbon feedstock. In our previous work,^[1,2] we demonstrated the in-situ capture and utilization of CO₂ in oxidative dehydrogenation of C₂H₆ to C₂H₄ (CO₂-ODHE) over dual function materials (DFMs) comprising CaO and Cr/H-ZSM-5. In this follow-up work, we investigated the process performance of the materials in more detail using structured configurations by formulating the materials into monolithic structures via additive manufacturing. To study the effect of bed configuration, two bed designs were considered: layered-bed in which adsorbent (CaO) and catalyst (Cr₁₀/HZSM-5) were printed and stacked on top of each other, and single-layer bed where the adsorbent-catalyst materials were first printed together and loaded into the bed as a single monolithic structure. The capture-reaction results indicated that layered-bed outperforms the single-layer bed in terms of both capture and ODHE reaction performances, displaying a CO₂ capture capacity of 4 mmol/g, C₂H₆ conversion of 42.5%, and C₂H₄ selectivity and yield of 90.6% and 38.6%, respectively, under semi-isothermal adsorption-reaction conditions (600-700 °C). In the next step, we systematically investigated the effects of reaction temperature, weight hourly space velocity (WHSV), C₂H₆ feed concentration, and cell density on the performance of layered-bed monoliths. The results were then used to extract kinetic parameters through a combination of power law and nonlinear regression techniques. Under optimum conditions, the 3D-printed DFMs exhibited comparable capture-catalytic activity to powders with enhanced C₂H₄ selectivity and cyclic stability.

References

1. Al-Mamoori et al. Appl. Catal. B Environ 278, 119329 (2020).
2. Al-Mamoori et al. Energy & Fuels 34 (11), 14483–14492 (2020).