Engineering Thermally Resistant Catalytic Particles for Oxidative Coupling of Methane Using Spray-Drying and Incorporating SiC

Abstract

Oxidative coupling of methane (OCM) is a promising single-step route to convert natural gas to high-valued chemicals. It is generally agreed that Mn–Na–W catalysts offer a balanced conversion–selectivity trade-off. The present work outlines a novel SiC–SiO2 support synthesized by spray drying to extend the lifetime of the catalyst. Incorporating SiC into the support enables the exothermic reaction heat to be effectively dissipated, avoiding hotspots and thermal shocks, and increasing the thermal resistance. The spray drying technique yields particles with a consistent distribution of SiC inside the particles, amplifying the thermal resistance of the catalyst. Our kinetic results show that the spray dried catalyst with SiC has significantly higher stability at high C2 selectivity compared to the benchmark SiO2-supported catalyst prepared by wetness impregnation. This result is due to (1) the more uniform distribution of active phases and SiC provided by the spray drying methodology and (2) the greater thermal resistance provided by SiC, which avoids thermal shocking and stabilizes the Mn–Na–W phases during the long-term (70 h) stability test for OCM.

Decreasing the coking and deactivation of a reforming Ni-Ce/Al2O3 catalyst with intraparticle SiC in hydrogen production routes

“…However, as the main cause of the deactivation observed in Figure 7 is coking instead of sintering, the activity decay is primarily due to coking. In this case, having a stronger MSI, such as in the SiC-free catalyst, disfavors the sintering of Ni, in agreement with other studies [57,58]. The amount of deposited carbon was further measured using the TGA analysis, and the results are presented in Figure 9(a).…”

Enhancing the catalytic performance of Ni based catalysts in toluene reforming at low temperature by structuring on SiC extrudates

“…The high thermal conductivity of SiC inhibits the cold/hot spots and thermal shocks caused in the catalytic surface by the exothermicity or endothermicity of the reactions, keeping it under quasi isothermal conditions. 28,56,57 This avoids sintering and reduces the formation of coke deposits at the surface of the catalyst. Tar reforming and CO methanation are respectively highly endothermic and exothermic reactions and can lead to the formation of cold/hot spots in the catalytic surface, promoting the formation of coke and sintering of the metal particles.…”

Catalytic Routes for Direct Methane Conversion to Hydrocarbons and Hydrogen: Current State and Opportunities

“…Recently, a new approach where SiC particles are incorporated into the SiO 2 matrix of the catalyst through spray drying proves to be an efficient approach toward improvement of catalyst thermal stability. As a result, a novel MnNaW/SiO 2 –SiC catalyst with higher conversion and selectivity over time on stream compared to the traditional catalyst based on SiO 2 support was disclosed …”

“…As a result, a novel MnNaW/SiO 2 −SiC catalyst with higher conversion and selectivity over time on stream compared to the traditional catalyst based on SiO 2 support was disclosed. 130 2.2. Optimal Operating Conditions for OCM Reaction.…”