Direct synthesis of DImethyl ether from synGAS – DIGAS

DIGAS project aims at developing a heterogeneous catalytic process for the direct synthesis of dimethyl ether (DME) from sustainable sources and for several energy applications. The project goes in the frames of the Challenge “Clean, safe and effective energy” for the Young Scientist competition. Syngas and biosyngas (CO/CO2/H2 mixtures) are considered as intermediates to power and fuels from a variety of feedstock. Transformation of syngas, a key technology and a strategic resource, into liquid fuels by thermochemical conversion is one of priorities in the energy transition scenario. The DIGAS project targets a contribution to the development of a biofuel for several applications and markets.
The DIGAS project is focused on the direct one-step synthesis of DME from biomass derived syngas by reactions 3 CO + 3 H2 <=> CH3OCH3 + CO2 and 2 CO2 + 6 H2 <=> CH3OCH3 + 3 H2O. The process will require the presence of bi-functional catalysts with both metal and acidic functions. Metal sites of the catalysts are necessary to activate hydrogen and carbon oxides in the first step of the process - methanol formation; acidic properties of the catalysts will assure the dehydration of methanol into DME. The project final ambition is valorization of syngas ex biomass (CO/CO2/H2). This will allow developing local units for DME production, easily transportable; close to sources of biomass (for example, wood). Main goals of this research work are:
- to develop catalytic materials with different porosities and controlled acidities, selective in both formation of methanol and dehydration of methanol in DME (2 steps which are merged in one-step process),
- to define optimal conditions for the reaction (temperature, pressure, composition of reaction mixture…) using thermodynamic simulation programs,
- to study transformations of gas mixtures representing syngas ex biomass with different compositions CO/CO2/H2, catalytic activity will be also studied in the presence of others components of biosyngas ex biomass gasification: effect of water, methane, ethane, sulfur containing products and ammonia,
- to investigate the mechanism of the reaction and nature of active sites in the mixtures CO/H2 or CO2/H2 for finding the optimal catalytic system for biosyngas transformation into DME – DRIFT operando experiments under pressure will be employed for this task besides other techniques,
- to perform long-term catalytic tests for the assessment to catalysts’ stability and deactivation.
This both fundamental and applied research will profit from many analytical techniques (XRD, XPS, IR, TGA, SEM, TEM, TPR, TPD, NMR …) present in the laboratory. The plan of the investigation will apply the possibility to change porous structure and the content of catalytically active components in order to create new active and stable catalysts in direct DME production from biomass derived syngas. Thermodynamic simulations will be set up using processes simulations software ProSim+ and Aspen. Catalytic reactions will be carried out under pressure and reaction products will be analyzed by on-line gas chromatography. In the frames of this project it is planned to investigate the reactivity, robustness, selectivity and stability of the catalytic materials in the model reaction and to get a deeper insight on the mechanism of the direct conversion of biosyngas into DME.