Temporally and spatially resolved non intrusive measurement of temperature and species concentration profiles during catalytic production of synthetic methane in open cell foam catalysts (CARS4KAT)

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Transformation of energy systems towards a clean, reliable and economical supply demands long-term and large-scale energy storage solutions with concurrent decarbonization. A promising approach for this challenge are Power-to-X technologies which are imbedded within the national hydrogen strategy. The catalytic production of synthetic methane (CH4) from regenerative hydrogen (H2) and selectively separated carbon dioxide (CO2) is on the one hand basis for the large-scale and long-term storage capacity and on the other hand an attractive tool for sector coupling. Today mostly fixed-bed reactors with nickel-based bulk catalysts are used in technical relevant methanation systems. Due to the strong exothermic reaction and the volatile hydrogen supply these reactors are operated at kinetically unfavorable conditions or require complex heat removal systems. A promising alternative to enhance heat and mass transfer are highly porous, net-shaped open-cell foam catalyst supports. In combination with novel and robust coatings, improved catalysts are manufacturable. Basic understanding of local reaction as well as heat and mass transfer mechanisms is fundamental for catalyst design and process intensification but is often missing due to absence of local validation data. Therefore, there is a strong need for non-invasive, spatial and temporal resolved temperature and species concentration profiles inside the macrostructure of the catalyst. Here a new and for this application adapted coherent anti-Stokes Raman spectroscopy approach is developed and applied to measure simultaneous and non-intrusive temperature and multispecies concentration profiles (H2, CO2, CH4, CO, H2O, N2) inside catalytic open cell foams under dynamic conditions. Start up and cool down phases are of special interest. The objective are specially developed, titania supported and nickel-based open cell foam methanation catalysts that are suitable for large-scale Power-to-X applications. The local analysis of hot spots in the macroscopic cell structure, the formation of characteristic temperature profiles, the determination of local process parameters such as CO2-conversion and CH4-yield and the identification of back mixing zones and mass transfer limitations is necessary to manufacture catalysts with increased efficiency. Furthermore, other structured catalysts developed within the SPP 2080 can be investigated. Additionally, local parameters will be applied to existing models for heat and mass transfer (supported by Prof. Sundmacher) or kinetic models of fixed bed reactors and catalysts.This basic understanding of local reaction as well as heat and mass transfer mechanisms will be a substantial and necessary step towards the establishment of open-cell foam catalysts for the large-scale methanation of CO2. The combined competence of both project partners in the field of laser-based spectroscopy (TTS) and in the field of catalytic systems (LEUVT) is the crucial basis for the success.