www.cet-journal.com Page 1 Chemical Engineering & Technology Received: February 18, 2019; revised: April 18, 2019; accepted: June 11, 2019 This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the final Version of Record (VOR). This work is currently citable by using the Digital Object Identifier (DOI) given below. The final VoR will be published online in Early View as soon as possible and may be different to this Accepted Article as a result of editing. Readers should obtain the final VoR from the journal website shown below when it is published to ensure accuracy of information. The authors are responsible for the content of this Accepted Article. To be cited as: Chem. Eng. Technol. 10.1002/ceat.201900132 Link to final VoR: https://doi.org/10.1002/ceat.201900132 This article is protected by copyright. All rights reserved. CO2 methanation in microstructured reactors – catalyst development and process design Stefan Neuberg 1 *, Helmut Pennemann 1 , Vetrivel Shanmugam 1 , Raphael Thiermann 1 , Ralf Zapf 1 , Wojciech Gac 2 , Magdalena Greluk 2 , Witold Zawadski 2 , Gunther Kolb 1 1 Fraunhofer IMM, Carl-Zeiss Strasse 18-20, 55129 Mainz, Germany 2 Department of Chemical Technology, Faculty of Chemistry, Maria Curie-Sklodowska University, 3 M. Curie- Skłodowska Sq., 20-031 Lublin, Poland *Correspondence: Stefan Neuberg (E-mail: stefan.neuberg@imm.fraunhofer.de), Fraunhofer IMM, Carl-Zeiss Strasse 18-20, 55129 Mainz, Germany Abstract The sulphur tolerance of mono- and bimetallic ruthenium catalysts for CO2 hydrogenation was investigated in microchannel reactors. H2S was used as a model compound and it was shown that a Ru/CeO2 catalyst deactivates rapidly. Ni was a much better additive to improve the catalysts stability compared to Rh and serves as a “sulphur-trap”. The influence of the support was investigated showing that SiO2 supported catalyst has a higher stability and better selectivity compared to CeO2 and TiO2. A plant concept was developed comprising two step methanation with a first adiabatic reactor stage followed by a plate heat-exchanger reactor with integrated cooling which allows more than 97% CO2 conversion. A pilot plant will be put into operation in connection with a biogas plant and an electrolyser of 50 kW power consumption. Keywords: Methanation, Sabatier reaction, catalyst, sulphur tolerance 1. Introduction The increasing share of renewable energy generation sources in Germany creates a surplus of electric energy, when wind or sunlight is available. Therefore the storage of electric energy comes into focus to compensate the drawbacks of its irregular production by renewable sources [1]. The chemical storage of electric energy seems to be a viable solution. One obvious solution is the electrolysis of water to hydrogen and oxygen. However, hydrogen storage in large quantities remains an issue not easily resolved[2]. Alternatively it could be fed into the natural gas grid, which is well developed in Germany. However, the addition of hydrogen to natural gas is limited, because the flame propagation properties of natural gas are affected by hydrogen [3]. Therefore, the chemical conversion of hydrogen with carbon dioxide from renewable and non- renewable sources such as biogas plants or the steel industry is currently under investigation [4]. The methanation of carbon dioxide, which is also called the Sabatier process, is an exothermic reaction: