Strategies for the Intensification of CO₂ Valorization in the One-Step Dimethyl Ether Synthesis Process

Abstract

The intensification of CO 2 valorization has been theoretically studied in the direct synthesis of dimethyl ether (DME) carried out in a packed-bed reactor by means of two strategies pursuing the attenuation of the thermodynamic limitations of the process. Thus, the recycling of the nonconverted reactants, and the use of H 2 O perm-selective membranes, with different sweeping strategies has been studied. Special attention has been paid to improving the yield of DME and the conversion of CO 2 , seeking for a good balance between both objectives. The study has been conducted using the kinetic model previously established for a CuO−ZnO−MnO/SAPO-18 catalyst. Quantifying the deactivation kinetics in the kinetic model has allowed us to ascertain that both strategies contribute to attenuating deactivation. With a recirculation factor of 0.97, for a CO 2 /CO x ratio in the feed of 0.25, at 275 °C and 30 bar, a CO 2 conversion of 70% and a DME yield of 60% are achieved. Using in the simulation a membrane with a H 2 O permeability of 1 × 10 −7 mol s −1 m 2 Pa −1 and a H 2 O/H 2 selectivity of 4, feasible with H-SOD type zeolite membranes, increases CO 2 conversion up to 3.5−5% with regard to that obtained in a packed-bed reactor, and the upgrade in DME yield stands out, reaching an improvement of 25% for the hydrogenation of pure CO 2 , regardless of the sweeping strategy used (parallel or countercurrent mode, or the use of pure H 2 or H 2 + CO + CO 2 ).

Applications of Zeolites to C1 Chemistry: Recent Advances, Challenges, and Opportunities

“…Several types of zeolites with various framework topologies have been evaluated for conversion of CO 2 into DME and methanol products. [ 73 ] In a recent work, CuZnZr catalyst (CZZ) was combined with zeolites with three different topologies ( MOR , FER , and MFI ) for CO 2 hydrogenation to DME. [ 74 ] The Cu species metal loading (48–56%) and particle sizes (8–9 nm) of these three catalysts were equivalent.…”

“…For instance, a core–shell structure (CZZr@S‐11) with the CuO–ZnO–ZrO 2 catalyst as the core and the SAPO‐11 zeolite as the shell exhibited better performance when producing DME from CO 2 than a CZZr/S‐11 catalyst prepared via physical mixing. [ 73b ] The better performance of the CZZr@S‐11 catalyst was attributed to the “separation” of methanol synthesis (on metallic core sites) from methanol dehydration (on zeolite shell sites) in the core–shell structure. This prevented the metallic sites from being poisoned by water formed in the zeolites.…”

Análisis y relevancia de los procesos catalíticos para la remoción de azufre en los combustibles fósiles

“…Otros procesos importantes para la obtención de combustibles sintéticos son, por ejemplo, las investigaciones realizadas para la obtención de dimetil éter (DME), como sustituto de diésel, por medio de la deshidratación catalítica de metanol (Stepanenko et al, 2019;Bateni et al, 2019). Recientes trabajos también apuntan a la generación de combustibles sintéticos por medio de la captura de CO 2 y su posterior uso en el proceso de Fischer-Tropsch o en la producción de DME y otros compuestos de alto valor energético (Ateka et al, 2020). Sin duda alguna, los combustibles sintéticos presentan la ventaja de no contener sustancias nocivas como el S (y otros elementos), por lo cual, no sería necesario un proceso de remoción de las mismas.…”

Highly Conductive Structured Catalytic Reactors for One-Step Synthesis of Dimethyl Ether

“…The efficient removal of heat from the reaction zone is vital because the formation of hot spots could damage the catalyst by sintering, especially in this kind of system in which Cu-based catalyst are used. 21 − 23 Indeed, Azizi et al 5 affirm that one of the most important challenges in the synthesis of DME is to design a reactor providing maximum process intensity, advanced recovery of heat generated in the process, and preservation of catalyst activity.…”