Multi-Scale Studies of 3D Printed Mn–Na–W/SiO2 Catalyst for Oxidative Coupling of Methane

Abstract

This work presents multi-scale approaches to investigate 3D printed structured Mn–Na–W/SiO2 catalysts used for the oxidative coupling of methane (OCM) reaction. The performance of the 3D printed catalysts has been compared to their conventional analogues, packed beds of pellets and powder. The physicochemical properties of the 3D printed catalysts were investigated using scanning electron microscopy, nitrogen adsorption and X-ray diffraction (XRD). Performance and durability tests of the 3D printed catalysts were conducted in the laboratory and in a miniplant under real reaction conditions. In addition, synchrotron-based X-ray diffraction computed tomography technique (XRD-CT) was employed to obtain cross sectional maps at three different positions selected within the 3D printed catalyst body during the OCM reaction. The maps revealed the evolution of catalyst active phases and silica support on spatial and temporal scales within the interiors of the 3D printed catalyst under operating conditions. These results were accompanied with SEM-EDS analysis that indicated a homogeneous distribution of the active catalyst particles across the silica support.

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

“…In such a context, the oxidative coupling of methane (OCM) is an interesting catalytic route for the single-stage production of highly valued chemicals such as ethane and ethylene through a thermodynamically exothermic and unconstrained reaction. OCM has been described as a potential source of light olefins as opposed to current production ways (mainly naphtha and heavy oil steam cracking) since it could simplify the process from a technological and an environmental perspective . One of the main limitations that OCM faces is the reduced catalytic activity at low temperatures due to the very stable C–H bond in methane, thus requiring temperatures around 700–900 °C that typically lead to catalyst sintering and excessive CO X formation at the expense of C 2 products. , The involvement of both solid-catalyzed gas phase heterogeneous reactions and gas phase homogeneous reactions poses additional complications .…”

“…OCM has been described as a potential source of light olefins as opposed to current production ways (mainly naphtha and heavy oil steam cracking) since it could simplify the process from a technological and an environmental perspective . One of the main limitations that OCM faces is the reduced catalytic activity at low temperatures due to the very stable C–H bond in methane, thus requiring temperatures around 700–900 °C that typically lead to catalyst sintering and excessive CO X formation at the expense of C 2 products. , The involvement of both solid-catalyzed gas phase heterogeneous reactions and gas phase homogeneous reactions poses additional complications . Nonetheless, the discovery of a highly C 2 -selective catalyst that can make the process economically (>30% C 2 yield) viable is the biggest limitation that the OCM is facing at the moment …”

Recent developments in X-ray diffraction/scattering computed tomography for materials science

“…A considerable number of in situ catalytic XRD-CT studies have been performed at beamlines ID11, ID15A and ID31 of the ESRF, many by the Beale group, on aspects of oxidative coupling of methane (OCM) [113][114][115][116][117], partial oxidation (POX) of methane [28,118], CO 2 methanation [119], the low-temperature water-gas shift [120] and gas separation catalysts [121]. The catalytic conundrum that is coking has also been studied [122].…”

“…Catalysts used in the associated POX reaction have been studied, illustrating a spatial dependency for the formation of unstable Ni-Pd alloys, coke deposition and Ni sintering [ 28 ]. XRD-CT has also been used as part of a suite of multimodal characterization studies for a series of three-dimensional printed catalysts for use in OCM [ 116 ], gas separation [ 121 ] and CO 2 methanation [ 119 ], providing information about the spatial distribution of catalyst and assessing the fidelity of three-dimensional printing.…”

3D printed SrNbO2N photocatalyst for degradation of organic pollutants in water

“…18–21 Examples of the development and characterisation of the 3D printed microchannel catalysts can be found in our previous work. 22–25…”