Techno-economic assessment of the one-step CO₂conversion to dimethyl ether in a membrane-assisted process

This study investigates the impact of the membrane reactor (MR) technology with in-situ removal of water to boost the performance of the one-step DME synthesis via CO2 hydrogenation at process scale. Given the higher efficiency in converting the feedstock, the membrane reactor allows for a remarkable decrease in the main cost drivers of the process, i.e., the catalyst mass and the H2 feed flow, by ca. 39% and 64%, respectively. Furthermore, the MR-assisted process requires 46% less utilities than the conventional process, especially in terms of cooling water and refrigerant, with a corresponding decrease in environmental impact (i.e., 25% less CO2 emissions). Both the conventional and MR-assisted plants were found effective for the mitigation of the CO2 emissions, avoiding ca. 1.4-1.6 tonCO2/tonDME. However, given the higher reactor and process efficiency, the membrane technology contributes to a significant reduction (i.e., 25%) in the operating costs, which is a remarkable improvement in this OPEX intensive process. Nevertheless, the calculated minimum DME selling price (i.e., 1739 €/ton and 1960 €/ton for the MR-assisted and the conventional process, respectively) is over 3 times greater than the current DME market price. Yet, with the predicted decrease of renewable H2 price and a zero-to-negative cost for the CO2 feedstock, the MR-assisted system could become competitive with the benchmark between 2025 and 2050.</p

Kinetic modelling of the methanol synthesis from CO₂ and H₂ over a CuO/CeO₂/ZrO₂ catalyst:The role of CO₂ and CO hydrogenation

This work addresses the kinetics of the CO2 hydrogenation to methanol over a Cu/CeO2/ZrO2 catalyst studied using single-site, dual-sites and three adsorption sites kinetic models. Physicochemical constraints and statistical indicators are used as tool for model discrimination. The best performing model is used to elucidate the reaction mechanism and the relative roles of the Cu-sites and oxygen vacancies. The results show that the dissociative adsorption of H2 occurs on the Cu0 sites, while CO2 is attracted to the oxygen vacancies created by the CeO2-ZrO2 solid solution. Then, the adsorbed H interacts preferentially with the carbon atom, favouring the so-called “formate” route. The CO formed via the r-WGS reaction could either desorb to the gas phase or react via hydrogenation to methanol. Analysis of the relative contributions of the CO2 and CO hydrogenation (i.e. direct and indirect pathways, respectively) to the methanol synthesis reveals that the latter is in fact preferential at high temperatures (i.e. about 100% of methanol is produced from CO at 260 ⁰C and 30 bar), and it shows an optimum vs the H2:CO2 ratio (c.a. 7 at 200 ⁰C and 30 bar), which corresponds to the saturation of the Cu0 sites with H2. Thus, this work provides an essential tool (i.e., kinetic model) for the design of reactors and processes based on novel catalysts, and importantly, it offers a deeper understanding of the reaction mechanism as basis for further catalyst development.</p

Carbon molecular sieve membranes for water separation in CO₂ hydrogenation reactions:Effect of the carbonization temperature

Carbon membranes are a potentially attractive candidate for the in-situ removal of water vapor in CO2 hydrogenation reactions. Their hydrophilicity and pore structure can be tuned by properly adjusting the synthesis procedure. Herein, we assess the effect of the carbonization temperature (450–750 °C) on the performance of supported CMSM in terms of vapor/gas separation, in correlation with changes in their surface functionality and porous structure. FTIR spectra showed that the nature of the functional groups changes with the evolution of the carbonization step, leading to a gradual loss in hydrophilicity (i.e., OH stretching disappears at Tcarb ≥ 600 °C). The extent of water adsorption displays an optimum at Tcarb of 500 °C, with the membrane carbonized at 650 °C being the least hydrophilic. We found that the pore size distribution strongly influences the water permeance. At all Tcarb, adsorption-diffusion (AD) is the dominant transport mechanisms. However, as soon as ultra-micropores appear (Tcarb: 600–700 °C) molecular sieving (MS) contributes to an increase in the water permeance, despites a loss in hydrophilicity. At Tcarb ≥ 750 °C, MS pores disappear, causing a drop in the water permeance. Finally, the permeance of different gases (N2, H2, CO, CO2) is mostly affected by the pore size distribution, with MS being the dominant mechanism over the AD, except for CO2. However, the extent and mechanism of gas permeation drastically change as a function of the water content in the feed, indicating that gas/vapor molecules need to compete to access the pores of the membranes.</p

Developing the next generation of renewable energy technologies:an overview of low-TRL EU-funded research projects

A cluster of eleven research and innovation projects, funded under the same call of the EU’s H2020 programme, are developing breakthrough and game-changing renewable energy technologies that will form the backbone of the energy system by 2030 and 2050 are, at present, at an early stage of development. These projects have joined forces at a collaborative workshop, entitled ‘ Low-TRL Renewable Energy Technologies’, at the 10th Sustainable Places Conference (SP2022), to share their insights, present their projects’ progress and achievements to date, and expose their approach for exploitation and market uptake of their solutions.</p

Developing the next generation of renewable energy technologies:an overview of low-TRL EU-funded research projects

A cluster of eleven research and innovation projects, funded under the same call of the EU’s H2020 programme, are developing breakthrough and game-changing renewable energy technologies that will form the backbone of the energy system by 2030 and 2050 are, at present, at an early stage of development. These projects have joined forces at a collaborative workshop, entitled ‘ Low-TRL Renewable Energy Technologies’, at the 10th Sustainable Places Conference (SP2022), to share their insights, present their projects’ progress and achievements to date, and expose their approach for exploitation and market uptake of their solutions.</p

Sulfonated foam catalysts for the continuous dehydration of xylose to furfural in biphasic media

This paper demonstrates the use of sulfonated foam structures, acting both as catalyst and liquid-liquid contactor, during the continuous dehydration of xylose to furfural in biphasic media. First, we develop and optimize a coating procedure comprising a two-step polymerization technique (polypropylene and polystyrene-divinylbenzene), followed by swelling and sulfonation. The method was highly reproducible and led to a stable, well-adhered, 12–50 μm layer of sulfonic resin with an ion exchange capacity of 0.1 meq/cmfoam3. The catalytic foams showed the same activity than H2SO4 in terms of conversion and selectivity versus residence time and temperature. The enhanced mass transfer properties of the foam-based reactor facilitated rapid furfural extraction, thus allowing for higher temperature operations (ca. 20–50 °C higher) and shorter residence times (ca. 10 min vs. 4–5 h) than conventionally reported in the literature, while preserving high furfural selectivity (ca. 70–80%). Finally, the stability of the sulfonated foam catalyst during operation was demonstrated up to 170 °C, although higher temperatures led to a visible decay in activity. We conclude that the sulfonated foams show great potential for this application

Facile synthesis of catalytic AuPd nanoparticles within capillary microreactors using polyelectrolyte multilayers for the direct synthesis of H2O2

Microreactors present innovative solutions for problems pertaining to conventional reactors and therefore have seen successful application in several industrial processes. Yet, its application in heterogeneously catalyzed gas-liquid reactions has been challenging, mainly due to the lack of an easy and flexible methodology for catalyst incorporation inside these reactors. Herein, we report a facile technique for obtaining small (<2 nm) and well-distributed catalytic nanoparticles on the walls of silica-coated capillaries, that act as micro(channel) reactors. These particles are formed in situ on the reactor walls using polyelectrolyte multilayers (PEMs), built by layer-by-layer self-assembly. Manipulating the PEMs' synthesis condition gives easy control over metal loading, without compromising on particle size. Both monometallic (Au and Pd) and bimetallic (AuPd) nanoparticles were successfully obtained using this technique. Finally, these catalytic microreactors were found to exhibit exceptional activity for the direct synthesis of hydrogen peroxide from H2 and O2

Controlling the selectivity in the Fischer-Tropsch synthesis using foam catalysts: An integrated experimental and modeling approach

The Fischer-Tropsch synthesis (FTS) is widely applied to convert syngas to liquid fuels, being long-chain hydrocarbons (C5+) the preferred products. Combining experiments and first-principle simulations, this work analyzes the effect of intra and extra-particle mass transfer limitations on the FTS reaction rate and product selectivity using open-cell foams catalysts. Co/Al2O3 and Co/TiO2 catalysts were deposited on open-cell foam structures and tested for the FTS. A 1-D multi-scale first principle reactor model is developed in order to correlate the product distribution and the reactor performance with the system properties. Both experiments and modeling results demonstrate that an increase in the washcoat layer thickness leads to greater selectivity towards methane and that the reaction rate has a maximum at ca. 60 μm. The developed model is used to predict the foam-based reactor performance, under realistic industrial conditions, showing that the productivity to C5+ is severely affected by washcoat layers thicker than 50 μm.Fil: Aguirre, Alejo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; ArgentinaFil: Scholman, Esther. Technische Universiteit Eindhoven; Países BajosFil: van der Shaaf, John. Technische Universiteit Eindhoven; Países BajosFil: Neira d'Angelo, M. Fernanda. Technische Universiteit Eindhoven; Países Bajo

Kinetic modelling of the methanol synthesis from CO2 and H2 over a CuO/CeO2/ZrO2 catalyst: The role of CO2 and CO hydrogenation

This work addresses the kinetics of the CO2 hydrogenation to methanol over a Cu/CeO2/ZrO2 catalyst studied using single-site, dual-sites and three adsorption sites kinetic models. Physicochemical constraints and statistical indicators are used as tool for model discrimination. The best performing model is used to elucidate the reaction mechanism and the relative roles of the Cu-sites and oxygen vacancies. The results show that the dissociative adsorption of H2 occurs on the Cu0 sites, while CO2 is attracted to the oxygen vacancies created by the CeO2-ZrO2 solid solution. Then, the adsorbed H interacts preferentially with the carbon atom, favouring the so-called “formate” route. The CO formed via the r-WGS reaction could either desorb to the gas phase or react via hydrogenation to methanol. Analysis of the relative contributions of the CO2 and CO hydrogenation (i.e. direct and indirect pathways, respectively) to the methanol synthesis reveals that the latter is in fact preferential at high temperatures (i.e. about 100% of methanol is produced from CO at 260 ⁰C and 30 bar), and it shows an optimum vs the H2:CO2 ratio (c.a. 7 at 200 ⁰C and 30 bar), which corresponds to the saturation of the Cu0 sites with H2. Thus, this work provides an essential tool (i.e., kinetic model) for the design of reactors and processes based on novel catalysts, and importantly, it offers a deeper understanding of the reaction mechanism as basis for further catalyst development