Design of Highly Efficient Catalyst for Rational Way of Direct Conversion of Methane

I.Z Ismagilov,E Abbenhuis,J.L.G Fierro,E.V Matus,I.P Prosvirin,M.A Kerzhentsev,G Gerritsen,Z.R Ismagilov,R.M Navarro

doi:10.18321/ectj201

I.Z Ismagilov, E Abbenhuis + Show 7 more

Open Access

https://doi.org/10.18321/ectj201

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Abstract

Effects of composition and preparation method of MnNaW/SiO2 and LaSr/CaO catalysts on their physical-chemical properties and performance in oxidative coupling of methane (OCM) have been studied. For MnNaW/SiO2 catalysts the synthesis method and type of SiO2 have a significant effect on the texture, while the Na/W ratio determines the phase composition. The variation of preparation method and temperature of catalyst calcination allows regulation of the metal surface concentration and mode of metal distribution across the SiO2 support. For LaSr/CaO catalysts the synthesis method determines the specific surface area, surface and phase composition. Correlations between catalyst performance, preparation method and state of the catalyst were established. The rational preparation procedure and perspective composition of OCM catalyst have been developed. The 20La/CaO catalysts prepared by citrate sol-gel method were shown to provide ~20% C2 yield and ~40% methane conversion at 800 °C.

Highlights

Design of highly efficient catalyst for rational way of conversion of methane will solve such problems as effective utilization of natural gas and environmental protection [1,2,3,4,5,6,7]
The mixture slurry method provides formation of more active OCM materials at Na content less than 1.5 wt.%, while the impregnation method have an advantage at Na content above 1.5%. This is probably connected with particularity of crystallization and polymorphic transformations of different sources of SiO2 (amorphous SiO2 powder (I) and SiO2 sol (M)) that leads to different phase composition and texture characteristics of catalysts, as well as behaviour of metal distribution across support, red-ox properties of supported species and metal-support interaction
It was found that precise regulation of C2 product yields in the OCM reaction could be achieved by appropriate variation of composition and preparation conditions of catalysts

Summary

Introduction

Design of highly efficient catalyst for rational way of conversion of methane will solve such problems as effective utilization of natural gas and environmental protection [1,2,3,4,5,6,7]. The production of C2 hydrocarbons (i.e. ethylene + ethane) through the oxidative coupling of methane (OCM) is an attractive direct way of the natural gas utilization into the value added products A great deal of effort has been directed towards OCM with the use of mixed ionic-electronic conducting membranes (MIECM membranes), but only a few examples demonstrated a C2 yield higher than 30% [14,15,16]

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