Role of Pellet Geometry Controlled by 3D Printing on Catalytic Performance of Mn–Na2WO4-Based Systems in Oxidative Coupling of Methane

Abstract

Pellet catalysts dedicated to oxidative coupling of methane (OCM) were prepared with the assistance of 3D printing technology using the casting technique. In this approach, polymeric templates printed using digital light processing technology were applied for pellet catalyst shaping. Three series of cubic-type catalysts varying in external size and number of channels were produced by a one-step procedure of the templates filling with the paste containing Mn₂O₃, Na₂WO₄, α-Al₂O₃, and sodium silicate solution. The pellets containing 2 wt % of Mn₂O₃ and 5 wt % of Na₂WO₄ were characterized by X-ray fluorescence, X-ray diffraction, UV–vis diffuse reflectance, temperature-programmed reduction with H₂, scanning electron microscopy–energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy techniques and tested in OCM. The pellet catalysts exhibited excellent catalytic performance and stability vs time on stream. It has been found that the size of the pellets and their geometry have an impact on the catalytic performance and pumping resistance through the catalyst bed (drop pressure).