Alternative acid catalysts for the stable and selective direct conversion of CO2/CO mixtures into light olefins

Portillo, Ander; Ateka, Ainara; Ereña, Javier; Bilbao, Javier; Aguayo, Andrés T.

doi:10.1016/j.fuproc.2022.107513

Cited by 8 publications

(6 citation statements)

References 64 publications

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“…Also, after 100 h of TOS, the total amount of deposited coke was 4.0 wt %, indicating an almost steady state for the formation and decomposition of coke during the whole reaction period. Finally, the complete removal of coke deposited on the catalyst may require the use of stripping or oxidative combustion techniques . However, optimized reaction conditions, as well as an appropriate precoking treatment, can greatly increase the efficiency of the catalyst, so the development of fixed bed technology or moving bed technology for olefin production from CO 2 hydrogenation has become possible.…”

Section: Resultsmentioning

confidence: 99%

Modulating the Formation of Coke to Improve the Production of Light Olefins from CO₂ Hydrogenation over In₂O₃ and SSZ-13 Catalysts

Di,

Achour,

et al. 2023

Energy Fuels

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Moderately acidic aluminophosphates (SAPOs) are often integrated with methanol synthesis catalysts for the hydrogenation of CO 2 to olefins, but they suffer from hydrothermal decomposition. Here, an alternative SSZ-13 zeolite with high hydrothermal stability is synthesized and coupled with an In 2 O 3 catalyst in a hybrid system. Its performance regarding selectivity for olefins and coke formation was investigated for CO 2 hydrogenation under varying temperatures and pressures. Various reactions occur, producing mainly CO and different hydrocarbons. The results indicate that the hydrogenation of hydrocarbons are dominant at high temperatures (around 400 °C) over SSZ-13 zeolite with a high acid density and that the coke deposition rate is slow. Polymethylbenzenes are the main coke species, but the selectivity for light olefins is low among hydrocarbons at high temperatures. However, at low temperatures (around 325 °C), and especially under high pressure (40 bar), methanol disproportionation becomes significant. This results in an increased selectivity for light olefins; however, it also leads to a rapid coke deposition, which gives inactive adamantanes as the main coke species that block the pores and cause rapid deactivation. However, after coking at 325 °C and regeneration at 400 °C under the reaction atmosphere, the accumulated adamantanes can be decomposed into smaller coke species, which reopens the channel structure and generates modulated active sites within the zeolite, resulting in a higher yield of olefins without deactivation. The performances of acidic SSZ-13 zeolites, with varying ratios of Si/Al in transient experiments, further verified that a dynamic balance exists between the formation and degradation of coke within the SSZ-13 zeolite during a long-term CO 2 hydrogenation reaction. This balance can be achieved by optimizing the reaction conditions to match the acid density of the catalyst. Using the conditions of 20 bar and 375 °C, with a H 2 to CO 2 mole ratio of 3, the results obtained for the precoked hybrid catalysts of In 2 O 3 and SSZ-13 (Si/Al = 25) exhibited very stable activity, with the selectivity for light olefins (based on hydrocarbons formed) of max. 70% after 100 h time-on-stream. This work provides new insights into the design of stable hybrid catalysts, especially the influence of a precoking process for SSZ-13 zeolite in the production of light olefins.

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Section: Resultsmentioning

confidence: 99%

Modulating the Formation of Coke to Improve the Production of Light Olefins from CO₂ Hydrogenation over In₂O₃ and SSZ-13 Catalysts

Di,

Achour,

et al. 2023

Energy Fuels

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“…The preparation of In 2 O 3 –ZrO 2 was previously described in detail elsewhere by Portillo et al Briefly, a coprecipitation using In(NO 3 ) 3 (Sigma-Aldrich), Zr(NO 3 ) 4 (Panreac), and NH 4 CO 3 (Panreac) was carried out. The fresh and deactivated catalysts were extensively characterized in previous studies, , and their properties are presented in Section S1 (Table S1).…”

Section: Methodsmentioning

confidence: 99%

“…24 In previous studies, the excellent performance of the In 2 O 3 − ZrO 2 /SAPO-34 tandem catalyst for the selective production of light olefins was examined, 25 based on the synergy between the CO 2 adsorption capacity and hydrogenation activity of the oxygen vacancies on the In 2 O 3 −ZrO 2 catalyst surface, 26 and on the characteristic olefin selectivity of the CHA (Chabazite) structure of SAPO-34. 27 Additionally, the ability of this catalyst to simultaneously convert CO 2 and CO facilitates the cofeeding of syngas with CO 2 , which contributes to the sustainability process (when syngas is obtained from biomass or waste of the consumer society) and provides part of the required green H 2 . The negative synergistic effects of excessive concentration of H 2 O and methanol in the medium of the integrated process have also been studied.…”

Section: ■ Introductionmentioning

confidence: 99%

Kinetic Model for the Direct Conversion of CO₂/CO into Light Olefins over an In₂O₃–ZrO₂/SAPO-34 Tandem Catalyst

Portillo,

Parra,

Aguayo

et al. 2024

ACS Sustainable Chem. Eng.

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An original kinetic model is proposed for the direct production of light olefins by hydrogenation of CO 2 /CO (CO x ) mixtures over an In 2 O 3 −ZrO 2 /SAPO-34 tandem catalyst, quantifying deactivation by coke. The reaction network comprises 12 individual reactions, and deactivation is quantified with expressions dependent on the concentration of methanol (as coke precursor) and H 2 O and H 2 (as agents attenuating coke formation). The experimental results were obtained in a fixed-bed reactor under the following conditions: In 2 O 3 −ZrO 2 /SAPO-34 mass ratio, 0/1−1/0; 350−425 °C; 20−50 bar; H 2 /CO x ratio, 1−3; CO 2 /CO x ratio, 0−1; space time, 0−10 g In2O3−ZrO2 h mol C −1 , 0−20 g SAPO-34 h mol C −1; time, up to 500 h; H 2 O and CH 3 OH in the feed, up to 5% vol. The utility of the model for further scale-up studies is demonstrated by its application in optimizing the process variables (temperature, pressure, and CO 2 /CO x ratio). The model predicts an olefin yield higher than 7% (selectivity above 60%), a CO x conversion of 12% and a CO 2 conversion of 16% at 415 °C and 50 bar, for a CO 2 /CO x = 0.5 in the feed. Additionally, an analysis of the effect of In 2 O 3 −ZrO 2 and SAPO-34 loading in the configuration of the tandem catalyst is conducted, yielding 17% olefins and complete conversion of CO 2 under full water removal conditions.

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“…SAPO-34 silicoaluminophosphate has been ascertained as the appropriate acid catalyst for the in situ selective conversion of methanol into DME (Equation (3)) and of methanol/DME into olefins (Equation ( 4)) [24][25][26]. The dual cycle mechanism, with polymethyl benzenes and olefins as intermediates, is well-established [27].…”

Section: Introductionmentioning

confidence: 99%

Setting up In2O3-ZrO2/SAPO-34 Catalyst for Improving Olefin Production via Hydrogenation of CO2/CO Mixtures

et al. 2023

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The adequate configuration and the effect of the reduction was studied for the In2O3-ZrO2/SAPO-34 catalyst with the aim of improving its performance (activity and selectivity in the pseudo-steady state) for the hydrogenation of CO, CO2 and CO2/CO (COx) mixtures into olefins. The experiments were carried out in a packed bed reactor at 400 °C; 30 bar; a H2/COx ratio of 3; CO2/COx ratios of 0, 0.5 and 1; a space time (referred to as In2O3-ZrO2 catalyst mass) of 3.35 gInZr h molC−1; and a time on stream up to 24 h. The mixture of individual catalyst particles, with an SAPO-34 to In2O3-ZrO2 mass ratio of 1/2, led to a better performance than hybrid catalysts prepared via pelletizing and better than the arrangement of individual catalysts in a dual bed. The deactivation of the catalyst using coke deposition and the remnant activity in the pseudo-steady state of the catalyst were dependent on the CO2 content in the feed since the synergy of the capabilities of the SAPO-34 catalyst to form coke and of the In2O3-ZrO2 catalyst to hydrogenate its precursors were affected. The partial reduction of the In2O3-ZrO2/SAPO-34 catalyst (corresponding to a superficial In0/In2O3 ratio of 0.04) improved its performance over the untreated and fully reduced catalyst in the hydrogenation of CO to olefins, but barely affected CO2/CO mixtures’ hydrogenation.

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Alternative acid catalysts for the stable and selective direct conversion of CO2/CO mixtures into light olefins

Cited by 8 publications

References 64 publications

Modulating the Formation of Coke to Improve the Production of Light Olefins from CO₂ Hydrogenation over In₂O₃ and SSZ-13 Catalysts

Modulating the Formation of Coke to Improve the Production of Light Olefins from CO₂ Hydrogenation over In₂O₃ and SSZ-13 Catalysts

Kinetic Model for the Direct Conversion of CO₂/CO into Light Olefins over an In₂O₃–ZrO₂/SAPO-34 Tandem Catalyst

Setting up In2O3-ZrO2/SAPO-34 Catalyst for Improving Olefin Production via Hydrogenation of CO2/CO Mixtures

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Alternative acid catalysts for the stable and selective direct conversion of CO2/CO mixtures into light olefins

Cited by 8 publications

References 64 publications

Modulating the Formation of Coke to Improve the Production of Light Olefins from CO2 Hydrogenation over In2O3 and SSZ-13 Catalysts

Modulating the Formation of Coke to Improve the Production of Light Olefins from CO2 Hydrogenation over In2O3 and SSZ-13 Catalysts

Kinetic Model for the Direct Conversion of CO2/CO into Light Olefins over an In2O3–ZrO2/SAPO-34 Tandem Catalyst

Setting up In2O3-ZrO2/SAPO-34 Catalyst for Improving Olefin Production via Hydrogenation of CO2/CO Mixtures

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Modulating the Formation of Coke to Improve the Production of Light Olefins from CO₂ Hydrogenation over In₂O₃ and SSZ-13 Catalysts

Modulating the Formation of Coke to Improve the Production of Light Olefins from CO₂ Hydrogenation over In₂O₃ and SSZ-13 Catalysts

Kinetic Model for the Direct Conversion of CO₂/CO into Light Olefins over an In₂O₃–ZrO₂/SAPO-34 Tandem Catalyst