Enhanced Direct Dimethyl Ether Synthesis from CO<sub>2</sub>-Rich Syngas with Cu/ZnO/ZrO<sub>2</sub> Catalysts Prepared by Continuous Co-Precipitation

oleh: Sabrina Polierer, David Guse, Stefan Wild, Karla Herrera Delgado, Thomas N. Otto, Thomas A. Zevaco, Matthias Kind, Jörg Sauer, Felix Studt, Stephan Pitter

Format: Article
Diterbitkan: MDPI AG 2020-07-01

Deskripsi

The manufacturing of technical catalysts generally involves a sequence of different process steps, of which co-precipitation is one of the most important. In this study, we investigate how continuous co-precipitation influences the properties of Cu/ZnO/ZrO<sub>2</sub> (CZZ) catalysts and their application in the direct synthesis of dimethyl ether (DME) from CO<sub>2</sub>/CO/H<sub>2</sub> feeds. We compare material characteristics investigated by means of XRF, XRD, N<sub>2</sub> physisorption, H<sub>2</sub>-TPR, N<sub>2</sub>O-RFC, TEM and EDXS as well as the catalytic properties to those of CZZ catalysts prepared by a semi-batch co-precipitation method. Ultra-fast mixing in continuous co-precipitation results in high BET and copper surface areas as well as in improved metal dispersion. DME synthesis performed in combination with a ferrierite-type co-catalyst shows correspondingly improved productivity for CZZ catalysts prepared by the continuous co-precipitation method, using CO<sub>2</sub>-rich as well as CO-rich syngas feeds. Our continuous co-precipitation approach allows for improved material homogeneity due to faster and more homogeneous solid formation. The so-called “chemical memory” stamped during initial co-precipitation is kept through all process steps and is reflected in the final catalytic properties. Furthermore, our continuous co-precipitation approach may be easily scaled-up to industrial production rates by numbering-up. Hence, we believe that our approach represents a promising contribution to improve catalysts for direct DME synthesis.