Direct hydrogenation of CO2 into DME: catalytic and technological aspects

CCU-related technologies can represent challenging strategies suitable to explore new concepts and opportunities for catalytic and industrial development. In this view, the production of dimethyl ether (DME) from the direct catalytic hydrogenation of CO2 appears as a viable approach, able to meet also the ever-increasing need for alternative environmentally-friendly fuels and energy carriers. Although several papers document a relatively high productivity on catalytic systems prepared by simple mixing between a methanol catalyst and an acidic matrix, the need for a relatively higher degree of inter-dispersion among the components is boosting the scientific interest towards the integration of a multi-functionality necessary for reaction within a single catalyst, so to realize a more efficient mass transfer of methanol formed on metal-oxide sites to the acid sites. This lecture will be focused on the performance of hybrid CuZnZr-zeolite catalysts, tested in a fixed bed reactor under direct CO2-to-DME hydrogenation conditions (i.e., TR, 200-260 °C; PR, 3.0 MPa; CO2/H2, 1/3 v/v). Particular attention will be addressed on the clues related to the reaction mechanism with the aim to ascertain the controlling step preventing the achievement of high CO2 conversion per pass below 220 °C. The audience will have also the opportunity to learn more about the technological aspects associated to the direct production of DME, suggesting possible solutions for a sustainable process chain. On the whole, people working in this field will acquire new information addressing a practical solution to a serious environmental and economical problem linked to the management of CO2 emissions in atmosphere.