Sorption Enhanced DME Synthesis (SEDMES) is a feasible approach to increase DME production from CO2-rich syngas.

No abstract

Dimethyl ether (DME) is an advanced second-generation biofuel produced via methanol dehydration over acid catalysts such as γ-Al 2 o 3 , at temperatures above 240 °C and pressures above 10 bar. Heteropolyacids such as tungstosilicic acid (HSiW) are Brønsted acid catalysts with higher DME production rates than γ-Al 2 o 3 , especially at low temperatures (140-180 °C). In this work, we show that the performance of supported HSiW for the production of DME is strongly affected by the nature of the support. TiO 2 and SiO 2 supported HSiW display the highest DME production rates of ca. 50 mmol DME /h/ g HSiW. Characterization of acid sites via 1 H-NMR, NH 3-isotherms and NH 3-adsrobed DRIFT reveal that HSiW/X have Brønsted acid sites, HSiW/TiO 2 showing more and stronger sites, being the most active catalyst. Methanol production increases with T until 200 °C where a rapid decay in methanol conversion is observed. This effect is not irreversible, and methanol conversion increases to ca. 90% by increasing reaction pressure to 10 bar, with DME being the only product detected at all reaction conditions studied in this work. The loss of catalytic activity with the increasing temperature and its increasing with reaction pressure accounts to the degree of contribution of the pseudo-liquid catalysis under the reaction conditions studied.

Among the different routes of ethylene production, the most plausible way to obtain it from renewable sources nowadays is the dehydration of bioethanol, which can be obtained from biomass or...

The synthesis of methanol from biomass-derived syngas can be challenging because of the high CO2 content in the bio-syngas, resulting in lower kinetics and higher catalyst deactivation. This work explores the in situ pre-treatment of a CO2-rich syngas with a CO2/CO ratio equal to 1.9 through the reverse-water gas shift reaction with the aim of adjusting this ratio to a more favorable one for the synthesis of methanol with Cu-based catalysts. Both reactions take place in two catalytic beds placed in the same reactor, thus intensifying the methanol process. The water produced during syngas conditioning is removed by means of a sorbent zeolite to prevent the methanol catalyst deactivation and to shift the equilibrium towards the methanol formation. The combination of the CO2 shifting and the water sorption strategies lead to higher productivities of the catalytic bed and, under certain reaction conditions, to higher methanol productions.