Optimizing Sorption Enhanced Methanation (SEM) of CO2 with Ni3Fe + LTA 5 A mixtures

Abstract

This study investigates the integration of catalytic CO₂ methanation and water adsorption using a Ni-Fe-based catalyst and LTA 5 A zeolite to enhance methane production via the Sabatier reaction. By mitigating thermodynamic limitations through in situ water removal, the research explores key operational parameters, including temperature, space velocity, and H₂:CO₂ feed ratios, to optimize process performance. The findings highlight that a temperature of 300 °C, a WHSV of 1.50 × 10⁴ (STP) mL·g_cat⁻¹·h⁻¹ (4.86 g_CO2·g_cat⁻¹·h⁻¹), and a H₂:CO₂ molar ratio equal to 5:1, result in enhanced methane yields, shifting thermodynamic equilibrium due to water sorption during initial stages. The presence of methane in the feed, representative of a biogas, demonstrated negligible effects on methane yields under optimal conditions, underscoring the method’s feasibility for direct biogas upgrading. While the process achieved significant intensification, challenges such as loss of activity of the bed of solids (catalyst plus water adsorbent) were identified, necessitating further advancements in both catalyst and adsorbent stability, as well as a deeper study on their interaction. The study provides a pathway for scaling up adsorption-enhanced methanation technologies to achieve renewable methane production, addressing the dual goals of carbon management and energy storage.