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28 pages, 5714 KiB

Open AccessArticle

Quantification of the Microwave Effect in the Synthesis of 5-Hydroxymethylfurfural over Sulfonated MIL-101(Cr)

by Noor Aljammal, Jeroen Lauwaert, Bert Biesemans, Francis Verpoort, Philippe M. Heynderickx and Joris W. Thybaut

Catalysts 2023, 13(3), 622; https://doi.org/10.3390/catal13030622 - 20 Mar 2023

Cited by 2 | Viewed by 2334

Abstract

The potential benefits of microwave irradiation for fructose dehydration into 5 hydroxymethylfurfural (5-HMF) have been quantified over a sulfonated metal–organic framework (MOF), MIL 101(Cr)-SO₃H. The effects of temperature (140–170 °C), batch time (5–300 min), and catalyst-to-substrate ratio (0.1–0.01 g/g) were systematically [...] Read more.

The potential benefits of microwave irradiation for fructose dehydration into 5 hydroxymethylfurfural (5-HMF) have been quantified over a sulfonated metal–organic framework (MOF), MIL 101(Cr)-SO₃H. The effects of temperature (140–170 °C), batch time (5–300 min), and catalyst-to-substrate ratio (0.1–0.01 g/g) were systematically mapped. After 10 min of microwave (MW) irradiation at 140 °C in a DMSO–acetone reaction medium, practically complete fructose conversion was obtained with a 70% yield of 5-HMF. Without MW, i.e., using conventional heating (CH) at the same conditions, the fructose conversion was limited to 13% without any 5-HMF yield. Rather, 90 min of CH was required to reach a similarly high conversion and yield. The profound impact of moving from CH towards MW conditions on the reaction kinetics, also denoted as the microwave effect, has been quantified through kinetic modeling via a change in the Gibbs free energy of the transition state. The modeling results revealed an eight-fold rate coefficient enhancement for fructose dehydration owing to MW irradiation, while the temperature dependence of the various reaction steps almost completely disappeared in the investigated range of operating conditions. Full article

(This article belongs to the Special Issue 10th Anniversary of Catalysts: Feature Papers in Catalytic Reaction Engineering)

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20 pages, 8110 KiB

Open AccessFeature PaperArticle

Effect of the Calcination Temperature of LaNiO₃ on the Structural Properties and Reaction Performance of Catalysts in the Steam Reforming of Methane

by Yujie Wang, Shuairen Qian, Yuxin Chen, Binhang Yan and Yi Cheng

Catalysts 2023, 13(2), 356; https://doi.org/10.3390/catal13020356 - 6 Feb 2023

Cited by 4 | Viewed by 2563

Abstract

The steam reforming of methane (SRM) reaction is a significant process for efficient syngas generation and for promising distributed hydrogen production. In this work, a series of LaNiO₃ oxides were prepared using the Pechini method, calcined from 600 °C to 900 °C [...] Read more.

The steam reforming of methane (SRM) reaction is a significant process for efficient syngas generation and for promising distributed hydrogen production. In this work, a series of LaNiO₃ oxides were prepared using the Pechini method, calcined from 600 °C to 900 °C and tested for the SRM reaction. Fresh, reduced, and used samples were characterized using STA-MS-FTIR, in situ and ex situ XRD, N₂ physical adsorption, H₂-TPR, TEM, TPO, and Raman. The results show that LaNiO₃ begins to crystallize at about 550 °C, and the increase in calcination temperature results in the following differences in the properties of the LaNiO₃ samples: larger LaNiO₃ grains, smaller specific surface area, higher reduction temperature, smaller Ni⁰ grains reduced from the bulk phase, and stronger metal–support interaction. The maximum CH₄ conversion could be achieved over LaNiO₃ calcinated at 800 °C. In addition, the effect of steam-to-carbon ratio (S/C) on the performance of the SRM reaction was studied, and a S/C of 1.5 was found to be optimal for CH₄ conversion. Too strong a metal–support interaction and too much unreacted steam causes a loss of catalytic activity. Finally, it was also proved using TPO and Raman that an increase in calcination temperature improves the carbon deposition resistance of the catalyst. Full article

(This article belongs to the Special Issue 10th Anniversary of Catalysts: Feature Papers in Catalytic Reaction Engineering)

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13 pages, 3460 KiB

Open AccessArticle

Kinetics of Heavy Reformate Conversion to Xylenes over MCM-41 on Zeolite Beta Composite Catalyst

by Syed Ahmed Ali and Mohammad Mozahar Hossain

Catalysts 2023, 13(2), 335; https://doi.org/10.3390/catal13020335 - 2 Feb 2023

Cited by 1 | Viewed by 1598

Abstract

Commercial heavy reformate is converted over MCM-41 on zeolite beta composite catalyst to produce mixed xylenes in a fluidized-bed batch reactor. The heavy reformate feedstock contains 67.4 wt.% trimethyl benzenes (TMBs) and 31.1 wt.% methyl ethyl benzenes (MEBs). The experiments were carried out [...] Read more.

Commercial heavy reformate is converted over MCM-41 on zeolite beta composite catalyst to produce mixed xylenes in a fluidized-bed batch reactor. The heavy reformate feedstock contains 67.4 wt.% trimethyl benzenes (TMBs) and 31.1 wt.% methyl ethyl benzenes (MEBs). The experiments were carried out at 300, 350 and 400 °C, while the reaction times were varied between 5 and 20 s. The conversion of MEBs was more than two times the conversion of TMBs. The selectivity to xylenes was quite high (60–65 wt.%) but changed very little with reaction time or temperature. A kinetic model was developed using a five-reaction network. The product composition obtained from the estimated kinetic parameters closely matches the experimental results, which confirms the validity of the assumptions made for kinetic modeling. The trend in the apparent activation energies of the reactions was in accordance with the relative size of the reactant molecules, and the lowest activation energy was for the transalkylation of TMBs with toluene to produce xylenes. Full article

(This article belongs to the Special Issue 10th Anniversary of Catalysts: Feature Papers in Catalytic Reaction Engineering)

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23 pages, 8224 KiB

Open AccessArticle

Pervaporation Membrane-Catalytic Reactors for Isoamyl Acetate Production

by Jesús David Quintero-Arias, Izabela Dobrosz-Gómez, Hugo de Lasa and Miguel-Ángel Gómez-García

Catalysts 2023, 13(2), 284; https://doi.org/10.3390/catal13020284 - 27 Jan 2023

Viewed by 1754

Abstract

This study reports the analysis and design of a liquid phase esterification process to convert acetic acid with isoamyl alcohol into isoamyl acetate via reactive pervaporation, in the presence of an Amberlite IR-120 ion exchange resin catalyst. To accomplish this, a catalytic reactor [...] Read more.

This study reports the analysis and design of a liquid phase esterification process to convert acetic acid with isoamyl alcohol into isoamyl acetate via reactive pervaporation, in the presence of an Amberlite IR-120 ion exchange resin catalyst. To accomplish this, a catalytic reactor is coupled with a separation membrane unit (Pervaporation Membrane Reactor (PVMR)). In the proposed unit, the chemical reaction equilibrium is favorably shifted towards isoamyl acetate formation by removing water with the help of a separation membrane. The study is developed by using relevant thermodynamics, kinetics, and membrane transport models, and by considering different catalytic reactor-pervaporator membrane configurations such as: (a) a two-step continuous fixed bed-pervaporator process (FBR+PVMU), (b) a two-step continuous slurry reactor-pervaporator process (SR+PVMU), (c) a single-step integrated fixed bed-pervaporator reactor (IFBPVMR), and d) a single step integrated slurry-pervaporator reactor (ISPVMR). The performance of the PVMRs is evaluated by using a R recycle ratio, a Ω membrane area to reactor volume ratio, and D_a Damköhler dimensionless parameters. From the various proposed configurations, it is shown that the integrated plug flow reactor-pervaporation reactor (IFBPVMR) provides the best performance. On the basis of various simulations and design charts developed in the present study, operational conditions leading to optimum ester yields as high as 0.94 are predicted. These results provide a valuable prospect for the industrial scale-up and implementation of isoamyl acetate production units. Full article

(This article belongs to the Special Issue 10th Anniversary of Catalysts: Feature Papers in Catalytic Reaction Engineering)

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19 pages, 5635 KiB

Open AccessFeature PaperArticle

Development of Innovative Structured Catalysts for the Catalytic Decomposition of N₂O at Low Temperatures

by Eugenio Meloni, Marco Martino, Simona Renda, Olga Muccioli, Pluton Pullumbi, Federico Brandani and Vincenzo Palma

Catalysts 2022, 12(11), 1405; https://doi.org/10.3390/catal12111405 - 10 Nov 2022

Cited by 2 | Viewed by 1961

Abstract

Nitrous oxide (N₂O), produced from several human activities, is considered a greenhouse gas with significant environmental impacts. The most promising abatement technology consists of the catalytic decomposition of N₂O into nitrogen and oxygen. Many recently published papers dealing with [...] Read more.

Nitrous oxide (N₂O), produced from several human activities, is considered a greenhouse gas with significant environmental impacts. The most promising abatement technology consists of the catalytic decomposition of N₂O into nitrogen and oxygen. Many recently published papers dealing with N₂O catalytic decomposition over Ni-substituted Co₃O₄ are related to the treatment of N₂O concentrations less than 2 vol% in the feed stream. The present work is focused on developing catalysts active in the presence of a gaseous stream richer in N₂O, up to 20 vol%, both as powder and in structured configurations suitable for industrial application. With this aim, different nickel-cobalt mixed oxides (Ni_xCo_1−xCo₂O₄) were prepared, characterized, and tested. Subsequently, since alumina-based slurries assure successful deposition of the catalytic species on the structured carrier, a screening was performed on three nickel-cobalt-alumina mixed oxides. As the latter samples turned out to be excellent catalysts for the N₂O decomposition reaction, the final catalytic formulation was transferred to a silicon carbide monolith. The structured catalyst led to the following very promising results: total N₂O conversion and selectivity towards N₂ and O₂ were reached at 510 °C by feeding 20 vol% of N₂O. It represents an important achievement in the view of developing a more concretely applicable catalytic system for industrial processes. Full article

(This article belongs to the Special Issue 10th Anniversary of Catalysts: Feature Papers in Catalytic Reaction Engineering)

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11 pages, 2602 KiB

Open AccessArticle

Experimental Investigation of Metal-Based Calixarenes as Dispersed Catalyst Precursors for Heavy Oil Hydrocracking

by Mohamed Ibrahim, Fahad A. Al-Zahrani, Francisco J. Diaz, Tareq Al-Attas, Hasan Zahir, Syed A. Ali, Mohammed Abdul Bari Siddiqui and Mohammad M. Hossain

Catalysts 2022, 12(10), 1255; https://doi.org/10.3390/catal12101255 - 17 Oct 2022

Cited by 6 | Viewed by 1944

Abstract

Slurry-phase hydrocracking utilizing metal-containing oil-soluble compounds as precursors of dispersed catalysts is an effective approach for heavy oil upgrading. We propose applying metal-based p-tert-butylcalix[6]arene (TBC[6]s) organic species as dispersed catalyst precursors to enhance catalytic hydrogenation reactions involved in the upgrading of vacuum gas [...] Read more.

Slurry-phase hydrocracking utilizing metal-containing oil-soluble compounds as precursors of dispersed catalysts is an effective approach for heavy oil upgrading. We propose applying metal-based p-tert-butylcalix[6]arene (TBC[6]s) organic species as dispersed catalyst precursors to enhance catalytic hydrogenation reactions involved in the upgrading of vacuum gas oil (VGO). Co- and Ni-based TBC[6]s were synthesized and characterized by SEM-EDX, ICP, XRD, and FT-IR. The thermogravimetric and calorimetric behaviors of the synthesized complexes, which are key properties of dispersed hydrocracking catalysts, were also explored. The experimental evaluation of the synthesized catalyst precursors show that the synthesized metal-based TBC[6] catalyst precursors improved the catalytic hydrogenation reactions. A co-catalytic system was also investigated by adding a commercial, first-stage hydrocracking supported catalyst in addition to the dispersed catalysts. The naphtha yields increased from 10.7 wt.% for the supported catalyst to 11.7 wt.% and 12 wt.% after adding it along with Ni-TBC[6] and Co-TBC[6], respectively. Mixing the metal-based precursors resulted in elevated yields of liquid products due to the in situ generation of highly active Co–Ni bimetallic dispersed catalysts. Full article

(This article belongs to the Special Issue 10th Anniversary of Catalysts: Feature Papers in Catalytic Reaction Engineering)

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17 pages, 2580 KiB

Open AccessFeature PaperArticle

Impact of the Non-Uniform Catalyst Particle Size on Product Selectivities in Consecutive Reactions

by Juan Rafael García, Claudia María Bidabehere and Ulises Sedran

Catalysts 2022, 12(10), 1214; https://doi.org/10.3390/catal12101214 - 12 Oct 2022

Viewed by 1587

Abstract

The analysis of consecutive reactions A→B→C in porous catalyst particles, where the simultaneous processes of diffusion and chemical reactions take place and both reactant and products are subjected to diffusion limitations, was performed for catalyst particles with non-uniform sizes, [...] Read more.

The analysis of consecutive reactions A→B→C in porous catalyst particles, where the simultaneous processes of diffusion and chemical reactions take place and both reactant and products are subjected to diffusion limitations, was performed for catalyst particles with non-uniform sizes, a fact that has not been considered so far. The system comprises first-order consecutive irreversible reactions that proceed on spherical catalyst particles with a log-normal volume particle size distribution (PSD), which is typical in many catalytic applications. Regardless of the prevailing diffusion regime (chemical control, transition situation or intraparticle diffusion control), the yield of the intermediate product (B) reaches a maximum value as a function of the conversion of reactant (A), then decreases as a consequence of the prevalence of the secondary reaction that converts it into the secondary product (C). If intraparticle diffusion resistances affect the reactant species, given the relationship between the kinetic constants and the mean particle size, the selectivity to the intermediate product is negatively affected by the dispersion in PSD. The larger the dispersion in PSD, the stronger the negative impact. Full article

(This article belongs to the Special Issue 10th Anniversary of Catalysts: Feature Papers in Catalytic Reaction Engineering)

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18 pages, 4381 KiB

Open AccessArticle

On a Response Surface Analysis: Hydrodeoxygenation of Phenol over a CoMoS-Based Active Phase

by Itzayana Pinzón-Ramos, Carlos O. Castillo-Araiza, Jesús Andrés Tavizón-Pozos and José Antonio de los Reyes

Catalysts 2022, 12(10), 1139; https://doi.org/10.3390/catal12101139 - 28 Sep 2022

Cited by 2 | Viewed by 2346

Abstract

This work aims at assessing the hydrodeoxygenation (HDO) of phenol over a promising catalytic material: a CoMoS-based active phase with a Co/(Co + Mo) = 0.2, supported on a promising mixed oxide, Al₂O₃-TiO₂ (Al/Ti = 2). Particularly, to [...] Read more.

This work aims at assessing the hydrodeoxygenation (HDO) of phenol over a promising catalytic material: a CoMoS-based active phase with a Co/(Co + Mo) = 0.2, supported on a promising mixed oxide, Al₂O₃-TiO₂ (Al/Ti = 2). Particularly, to optimize the catalytic and kinetic performance of CoMoS/Al₂O₃-TiO₂, a response surface methodology (RSM) is carried out by following a Box–Behnken experimental design. The response variables are the initial reaction rate and the reaction selectivity, determined via a proper contribution analysis (𝜑) of both the direct hydrodeoxygenation (DDO) and the hydrogenation (HYD). At the same time, the operating conditions used as factors are the reaction temperature (280–360 °C), the total pressure (3–5.5 MPa), and the Mo loading (10–15 wt.%). The activity and selectivity are correlated to the catalysts’ physicochemical properties determined by XRD, UV-Vis DRS, TPR, and Raman Spectroscopy. Regarding the CoMo-based active phase, a Mo loading of 12.5 wt.% leads to the optimal reaction performance, which is associated with the lowest (Co + Mo)^oh/(Co + Mo)^th ratio. Concerning the operating conditions, a temperature of 360 °C and a total pressure of 5.5 MPa give rise to the optimal initial reaction rates, in which the DDO (𝜑 = 65%) is selectively favored over HYD (𝜑 = 35%). Full article

(This article belongs to the Special Issue 10th Anniversary of Catalysts: Feature Papers in Catalytic Reaction Engineering)

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21 pages, 4684 KiB

Open AccessArticle

Heteropolyacid Incorporated Bifunctional Core-Shell Catalysts for Dimethyl Ether Synthesis from Carbon Dioxide/Syngas

by Birce Pekmezci Karaman, Nuray Oktar, Gülşen Doğu and Timur Dogu

Catalysts 2022, 12(10), 1102; https://doi.org/10.3390/catal12101102 - 23 Sep 2022

Cited by 11 | Viewed by 1746

Abstract

Core-shell-type catalysts, which are synthesized by encapsulating the Cu-ZnO-Alumina type methanol synthesis catalyst (CZA) by silicotungstic acid (STA)-incorporated mesoporous alumina, were prepared following a hydrothermal route and tested in DME synthesis from syngas and CO₂. Activity tests, which were performed in [...] Read more.

Core-shell-type catalysts, which are synthesized by encapsulating the Cu-ZnO-Alumina type methanol synthesis catalyst (CZA) by silicotungstic acid (STA)-incorporated mesoporous alumina, were prepared following a hydrothermal route and tested in DME synthesis from syngas and CO₂. Activity tests, which were performed in the pressure range of 30–50 bar, and the temperature range of 200–300 °C, with different feed compositions (CO₂/CO/H₂: 50/-/50, 40/10/50, 25/25/50, 10/40/50) showed that the best-operating conditions for the highest DME yield were 275 °C and 50 bar. Results proved that the presence of CO₂ in the syngas had a positive effect on the DME yield. The total conversion of CO + CO₂ increased with an increase in CO₂/CO ratio. An overall conversion of CO + CO₂ and DME selectivity values were obtained as 65.6% and 73.2%, respectively, with a feed composition of H₂/CO₂/CO = 50/40/10. Synthesis of methanol using the CZA catalyst from the CO₂-containing gas mixtures was also investigated, and the total conversion of CO + CO₂ and methanol selectivity values of 32.0% and 83.6%, respectively, were obtained with the H₂/CO₂/CO = 50/40/10 gas mixture. Results proved that the new STA incorporated core-shell-type bifunctional catalysts were highly promising for the conversion of CO_2-containing syngas to DME. Full article

(This article belongs to the Special Issue 10th Anniversary of Catalysts: Feature Papers in Catalytic Reaction Engineering)

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17 pages, 1768 KiB

Open AccessFeature PaperArticle

Hydrogen Pressure as a Key Parameter to Control the Quality of the Naphtha Produced in the Hydrocracking of an HDPE/VGO Blend

by Francisco J. Vela, Roberto Palos, Javier Bilbao, José M. Arandes and Alazne Gutiérrez

Catalysts 2022, 12(5), 543; https://doi.org/10.3390/catal12050543 - 16 May 2022

Cited by 5 | Viewed by 3293

Abstract

The hydrocracking of high-density polyethylene (HDPE) blended with vacuum gas oil (VGO) has been studied to assess the effect of H₂ pressure on the yield and composition of the products and with the aim of obtaining commercial fuels, mainly naphtha. The experiments [...] Read more.

The hydrocracking of high-density polyethylene (HDPE) blended with vacuum gas oil (VGO) has been studied to assess the effect of H₂ pressure on the yield and composition of the products and with the aim of obtaining commercial fuels, mainly naphtha. The experiments have been performed using a PtPd/HY catalyst in a semibatch reactor under the following conditions: H₂ pressure, 20–110 bar; 440 °C; catalyst to feed ratio, 0.1 g_cat (g_feed)⁻¹; HDPE to total feed ratio, 0.2 g_HDPE (g_feed)⁻¹; and reaction time, 2 h. The composition of the main fractions produced (gas, naphtha, and light cycle oil) reveals the interest in carrying out the process at 110 bar. Thus, conversions of 96 and 79% for the removal of heavy hydrocarbons and the removal of HDPE molecules have been obtained, respectively, together with a yield of naphtha of 53.4 wt%. This naphtha is mainly paraffinic, and it has a RON of 91.5 (within the commercial standards). Furthermore, three fractions have been observed in the analysis (temperature-programmed oxidation) of the coke. This analysis reveals that at 110 bar, the coke retained in the HY zeolite cages is less developed and burns at a moderate temperature. Full article

(This article belongs to the Special Issue 10th Anniversary of Catalysts: Feature Papers in Catalytic Reaction Engineering)

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14 pages, 1679 KiB

Open AccessFeature PaperArticle

Kinetic Model of Catalytic Steam Gasification of 2-Methoxy-4-methylphenol Using 5% Ni–0.25% Ru/γAl₂O₃ in a CREC-Riser Simulator

by Alán Rubén Calzada Hernandez, Benito Serrano Rosales and Hugo de Lasa

Catalysts 2022, 12(3), 282; https://doi.org/10.3390/catal12030282 - 2 Mar 2022

Cited by 2 | Viewed by 2381

Abstract

Hydrogen is an energy vector with a great potential due its ample range of applications and clean combustion cycle. Hydrogen can be produced through biomass steam gasification, with novel catalysts being of significant value to implement this process. With this goal in mind, [...] Read more.

Hydrogen is an energy vector with a great potential due its ample range of applications and clean combustion cycle. Hydrogen can be produced through biomass steam gasification, with novel catalysts being of significant value to implement this process. With this goal in mind, in the present study, 5 wt % Ni/γAl₂O₃ promoted with 0.25 wt % Ru was synthesized and characterized. It is assumed that ruthenium facilitates hydrogen transfer to nickel oxide sites, promoting a hydrogen spillover effect, with the H₂ adsorbed on Ru being transported to Ni sites. To describe chemical changes, the present study considers a kinetic model involving Langmuir–Hinshelwood-based rate equations, as a sum of independent reactions, with this being applied to the steam gasification of 2-methoxy-4-methylphenol (2M4MP). This tar biomass surrogate was studied in a fluidized CREC (Chemical Reactor Engineering Centre) Riser Simulator reactor, at different reaction times (5, 20 and 30 s.) and temperatures (550 °C, 600 °C and 650 °C). The proposed kinetics model was fitted to the experimentally observed H₂, CO₂, CO, CH₄ and H₂O concentrations, with the estimated pre-exponential factors and activation energies being in accordance with the reported literature data. It is anticipated that the postulated model could be of significant value for the modeling of other biomass conversion processes for hydrogen production using other supported catalysts. Full article

(This article belongs to the Special Issue 10th Anniversary of Catalysts: Feature Papers in Catalytic Reaction Engineering)

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16 pages, 6339 KiB

Open AccessEditor’s ChoiceArticle

Mixed Metal Oxides of M1 MoVNbTeO_x and TiO₂ as Composite Catalyst for Oxidative Dehydrogenation of Ethane

by Yuxin Chen, Dan Dang, Binhang Yan and Yi Cheng

Catalysts 2022, 12(1), 71; https://doi.org/10.3390/catal12010071 - 9 Jan 2022

Cited by 6 | Viewed by 2711

Abstract

Composite catalysts of mixed metal oxides were prepared by mixing a phase-pure M1 MoVNbTeO_x with anatase-phase TiO₂. Two methods were used to prepare the composite catalysts (the simple physically mixed or sol-gel method) for the improvement of the catalytic performance [...] Read more.

Composite catalysts of mixed metal oxides were prepared by mixing a phase-pure M1 MoVNbTeO_x with anatase-phase TiO₂. Two methods were used to prepare the composite catalysts (the simple physically mixed or sol-gel method) for the improvement of the catalytic performance in the oxidative dehydrogenation of ethane (ODHE) process. The results showed that TiO₂ particles with a smaller particle size were well dispersed on the M1 surface for the sol-gel method, which presented an excellent activity for ODHE. At the same operating condition (i.e., the contact time of 7.55 g_cat·h/mol_C2H6 and the reaction temperature of 400 °C), the M1-TiO₂-SM and M1-TiO₂-PM achieved the space time yields of 0.67 and 0.52 kg_C2H4/kg_cat/h, respectively, which were about ~76% and ~35% more than that of M1 catalyst (0.38 kg_C2H4/kg_cat/h), respectively. The BET, ICP, XRD, TEM, SEM, H₂-TPR, C₂H₆-TPSR, and XPS techniques were applied to characterize the catalysts. It was noted that the introduction of TiO₂ raised the V⁵⁺ abundance on the catalyst surface as well as the reactivity of active oxygen species, which made contribution to the promotion of the catalytic performance. The surface morphology and crystal structure of used catalysts of either M1-TiO₂-SM or M1-TiO₂-PM remained stable as each fresh catalyst after 24 h time-on-stream tests. Full article

(This article belongs to the Special Issue 10th Anniversary of Catalysts: Feature Papers in Catalytic Reaction Engineering)

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Review

Jump to: Research

28 pages, 52853 KiB

Open AccessReview

State-of-the-Art Review of Oxidative Dehydrogenation of Ethane to Ethylene over MoVNbTeO_x Catalysts

by Yuxin Chen, Binhang Yan and Yi Cheng

Catalysts 2023, 13(1), 204; https://doi.org/10.3390/catal13010204 - 16 Jan 2023

Cited by 11 | Viewed by 5153

Abstract

Ethylene is mainly produced by steam cracking of naphtha or light alkanes in the current petrochemical industry. However, the high-temperature operation results in high energy demands, high cost of gas separation, and huge CO₂ emissions. With the growth of the verified shale [...] Read more.

Ethylene is mainly produced by steam cracking of naphtha or light alkanes in the current petrochemical industry. However, the high-temperature operation results in high energy demands, high cost of gas separation, and huge CO₂ emissions. With the growth of the verified shale gas reserves, oxidative dehydrogenation of ethane (ODHE) becomes a promising process to convert ethane from underutilized shale gas reserves to ethylene at a moderate reaction temperature. Among the catalysts for ODHE, MoVNbTeO_x mixed oxide has exhibited superior catalytic performance in terms of ethane conversion, ethylene selectivity, and/or yield. Accordingly, the process design is compact, and the economic evaluation is more favorable in comparison to the mature steam cracking processes. This paper aims to provide a state-of-the-art review on the application of MoVNbTeO_x catalysts in the ODHE process, involving the origin of MoVNbTeO_x, (post-) treatment of the catalyst, material characterization, reaction mechanism, and evaluation as well as the reactor design, providing a comprehensive overview of M1 MoVNbTeO_x catalysts for the oxidative dehydrogenation of ethane, thus contributing to the understanding and development of the ODHE process based on MoVNbTeO_x catalysts. Full article

(This article belongs to the Special Issue 10th Anniversary of Catalysts: Feature Papers in Catalytic Reaction Engineering)

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23 pages, 2553 KiB

Open AccessEditor’s ChoiceReview

Catalytic Dehydration of Isopropanol to Propylene

by Jean-Luc Dubois, Georgeta Postole, Lishil Silvester and Aline Auroux

Catalysts 2022, 12(10), 1097; https://doi.org/10.3390/catal12101097 - 22 Sep 2022

Cited by 11 | Viewed by 6204

Abstract

Catalytic dehydration of isopropanol to propylene is a common reaction in laboratories to characterize the acid–base properties of catalysts. When acetone is produced, it is the sign of the presence of basic active sites, while propylene is produced on the acid sites. About [...] Read more.

Catalytic dehydration of isopropanol to propylene is a common reaction in laboratories to characterize the acid–base properties of catalysts. When acetone is produced, it is the sign of the presence of basic active sites, while propylene is produced on the acid sites. About 2/3rd of the world production of isopropanol is made from propylene, and the other third is made from acetone hydrogenation. Since the surplus acetone available on the market is mainly a coproduct of phenol synthesis, variations in the demand for phenol affect the supply position of acetone and vice versa. High propylene price and low demand for acetone should revive the industrial interest in acetone conversion. In addition, there is an increasing interest in the production of acetone and isopropanol from CO/CO₂ via expected more environmentally friendly biochemical conversion routes. To preserve phenol process economics, surplus acetone should be recycled to propylene via the acetone hydrogenation and isopropanol dehydration routes. Some critical impurities present in petrochemical propylene are avoided in the recycling process. In this review, the selection criteria for the isopropanol dehydration catalysts at commercial scale are derived from the patent literature and analyzed with academic literature. The choice of the process conditions, such as pressure, temperature and gas velocity, and the catalysts’ properties such as pore size and acid–base behavior, are critical factors influencing the purity of propylene. Dehydration of isopropanol under pressure facilitates the downstream separation of products and the isolation of propylene to yield a high-purity “polymer grade”. However, it requires to operate at a higher temperature, which is a challenge for the catalyst’s lifetime; whereas operation at near atmospheric pressure, and eventually in a diluted stream, is relevant for applications that would tolerate a lower propylene purity (chemical grade). Full article

(This article belongs to the Special Issue 10th Anniversary of Catalysts: Feature Papers in Catalytic Reaction Engineering)

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27 pages, 6263 KiB

Open AccessFeature PaperReview

The CREC Fluidized Riser Simulator a Unique Tool for Catalytic Process Development

by Hugo de Lasa

Catalysts 2022, 12(8), 888; https://doi.org/10.3390/catal12080888 - 12 Aug 2022

Cited by 7 | Viewed by 2480

Abstract

The CREC Riser Simulator is a mini-fluidized bench scale unit invented and implemented in 1992, at the CREC (Chemical Reactor Engineering Centre), University of Western Ontario The CREC Riser Simulator can be operated at short reaction times, in the 3 s to 20 [...] Read more.

The CREC Riser Simulator is a mini-fluidized bench scale unit invented and implemented in 1992, at the CREC (Chemical Reactor Engineering Centre), University of Western Ontario The CREC Riser Simulator can be operated at short reaction times, in the 3 s to 20 s range. The present review describes and evaluates the original basic concept of the 1992-CREC Riser Simulator Unit, and the improved design of the 2019-CREC Riser Simulator. Both the initial and the enhanced units are specially engineered to allow the rigorous assessment of both catalyst performance and catalytic reaction kinetics. Kinetic parameters of relatively simple and accurate mathematical models can be calculated using experimental data from the CREC Riser Simulator. Since its inception in 1992, the CREC Riser Simulator has been licensed to and manufactured for a significant number of universities and companies around the world. Several examples of scenarios where the CREC Riser Simulator can be employed to develop fluidized bed catalytic and heterogeneous reactor simulations are reported in this review. Among others, they include (a) hydrocarbon catalytic cracking, (b) the catalytic conversion of tar derived biomass chemical species, (c) steam and dry catalytic methane reforming, (d) the catalytic oxydehydrogenation of light paraffins, (e) the catalytic desulfurization of gasoline, and (f) biomass derived syngas combustion via chemical looping. In this review, special emphasis is given to the application of the CREC Riser Simulator to TIPB (tri-iso-propyl-benzene) catalytic cracking and the light paraffins catalytic oxydehydrogenation (PODH). Full article

(This article belongs to the Special Issue 10th Anniversary of Catalysts: Feature Papers in Catalytic Reaction Engineering)

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