Novel Cu–ZnO–ZrO2/UGSO catalysts for CO2 hydrogenation to methanol were developed using a metallu... more Novel Cu–ZnO–ZrO2/UGSO catalysts for CO2 hydrogenation to methanol were developed using a metallurgical residue as catalytic support, focusing on (i) the synergy of Cu/Zn/Zr and UGSO composition and (ii) UGSO modification, on catalytic activity and stability.
Abstract Coal fly ash (FA) supported Ni catalysts (Ni-FA) were synthesized via solid-state impreg... more Abstract Coal fly ash (FA) supported Ni catalysts (Ni-FA) were synthesized via solid-state impregnation method and systematically characterized by XRD, N2-physisorption, H2-TPR/TPD, H2-pulse chemisorption, XPS, TPO, TGA, Raman, and TEM. The effect of different parameters including (i) types of FA, (ii) Ni loading (2.5 - 15 wt.%), and (iii) reforming temperature (530 - 730 ⁰C), on the catalytic performance of yNi-FAx catalysts in glycerol steam reforming was investigated. The best performance in terms of activity (glycerol conversion to gas products = 98 %, H2 yield = 78.8 %) and stability (40 h, with low rate of coke formation and sintering 2.44 mgcoke• g catalyst -1 h-1) was achieved for 7.5%Ni-FA4 catalyst at 630 ⁰C. This was attributed to a higher dispersion of Ni° active sites and stronger interaction with the support, due to the higher surface area of FA4 and the presence of nepheline (providing vacancy sites for anchoring Ni particles) and thermostable mullite.
The sorption-enhanced steam reforming of glycerol (SESRG) is a sustainable approach to produce hi... more The sorption-enhanced steam reforming of glycerol (SESRG) is a sustainable approach to produce high-purity hydrogen in a single step by valorizing waste raw material. Fabricating Ni–CaO-based catal...
The Canadian Journal of Chemical Engineering, 2018
Selective hydroxylation of the C‐H bond of saturated hydrocarbon chains at room temperature is th... more Selective hydroxylation of the C‐H bond of saturated hydrocarbon chains at room temperature is the signature of an invaluable biocatalyst, cytochrome P450 BM3 from Bacillus megaterium. Despite this remarkable ability, because of the enzyme's inherent low stability and dependence on electron supply by expensive NADPH, developing stable and economic BM3 systems is a challenging subject. To improve BM3 stability, facilitate its reuse, and reduce the process cost, this study suggests covalent immobilization of R966D/W1046S P450 BM3 on glutaraldehyde pre‐activated super paramagnetic iron oxide nanoparticles (SPIONs). This double mutant consumes less expensive cofactors like NADH and BNAH and its immobilization on magnetic support facilitates its separation and reuse. Free and immobilized enzyme performances were evaluated by 10‐pNCA hydroxylation and BM3 selectivity (hydroxylation at ω (1–3) positions of a fatty acid) was confirmed in a reaction involving myristic acid. The enzyme ac...
International Journal of Greenhouse Gas Control, 2017
Packed-bed columns with immobilized human carbonic anhydrase II (hCA II) enzyme on fourth generat... more Packed-bed columns with immobilized human carbonic anhydrase II (hCA II) enzyme on fourth generation random packings offer an attractive way to implement CO 2 capture because of low pressure drop, high capacities and extremely large and uniform open area in every ring orientation. Enzyme-based CO 2 removal performance of countercurrent packed-bed column reactors was analyzed by means of a dynamic 3D model which links the macroscopic volume-averaged continuity, momentum and species balance equations in the liquid and gas phases with simultaneous diffusion and chemical reaction at the enzyme washcoat/liquid film scale level. The results reveal that this low-cost, green, and environmentally friendly technology could be an interesting option to CO 2 removal. The performance of packed-bed column reactors with immobilized hCA II enzyme on fourth generation random packings can be enhanced by diminishing the washcoat thickness, increasing the inlet buffer concentration and pK a constant and increasing the liquid velocity conserving a low pressure drop level. Also, operation with extra hCA II loadings allows to obtain higher CO 2 conversion and avoids the deterioration of the CO 2 hydration rate in long-term operation attributable to the decrease of hCA II enzyme activity.
A new membrane preparation method based on mechanical pore-plugging of the supports with appropri... more A new membrane preparation method based on mechanical pore-plugging of the supports with appropriate sized seeds followed by secondary zeolite growth by hydrothermal synthesis was optimized for the production of hydroxy-sodalite (hydroxy-SOD) membranes. A series of parameters were investigated during membrane production, including seed loading, presence of Teflon on the coarse side of the support, top-layer orientation in the autoclave, autoclave agitation, synthesis time and temperature, membrane post-synthesis treatment, and nature and pore size of the support (TiO 2 /SS, SS, Al 2 O 3 and ZrO 2 /TiO 2). Zeolite seeds and synthesized membranes were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and gas permeation. The gas permselective separation ability of these membranes was demonstrated from H 2 , N 2 , CO 2 and H 2 O permeation tests at temperature up to 250 C. The membranes fabricated with the optimized parameters achieved H 2 O/N 2 , H 2 O/CO 2 , and H 2 O/ H 2 ideal gas permselectivities of 5.1, 4.8 and 1.4 at 250 C, while providing a high water permeance (P H2O of 1.26 Â 10 À7 mol Pa À1 m À2 s À1) at the same temperature.
Industrial & Engineering Chemistry Research, 2003
Kinetic study of oxygen-free methane dehydrogenation and aromatization over Ru-Mo/HZSM-5 was carr... more Kinetic study of oxygen-free methane dehydrogenation and aromatization over Ru-Mo/HZSM-5 was carried out in a fixed-bed differential reactor under atmospheric pressure. The reaction temperature was varied between 873 and 973 K, and the methane feed fraction ranged from 50 to 90% v/v. A plausible reaction pathway involved in oxygen-free methane dehydrogenation and aromatization over Ru-Mo/HZSM-5 was proposed. Different models based on Langmuir-Hinshelwood-Hougen-Watson reaction mechanisms were tested to correlate the kinetic data. Among these models, the one postulating that the surface dehydrogenation reaction of adsorbed methane is rate-determining was successful in terms of physical likeliness (thermodynamic and kinetic parameters) and statistical goodness of fit. The activation energy, adsorption enthalpy, and entropy frequency were evaluated by means of Arrhenius or Van't Hoff relationships.
The effect of lithium chloride LiCl at salt mole fractions from 0.005 to 0.15 and at saturation o... more The effect of lithium chloride LiCl at salt mole fractions from 0.005 to 0.15 and at saturation on Ž. vapor-liquid equilibrium VLE of the binary acetone-methanol system has been experimentally investigated at 101.32 kPa using a modified Othmer equilibrium still, in order to elucidate the behavior of this mixture whose existing data are rather contradictory. The salting-out effect of the salt on the VLE of the mixed solvent was explained by the preferential solvation theory. The experimental data were correlated by the electrolytic NRTL Ž. model of Mock et al. 1986. The mean absolute deviations of the correlation for y and T are 0.018 and 0.74 K, respectively.
Al-stabilized CaO-nickel hybrid sorbent-catalyst prepared by limestone acidification. The hybrid ... more Al-stabilized CaO-nickel hybrid sorbent-catalyst prepared by limestone acidification. The hybrid sorbent-catalyst with 25 wt% NiO provided the best results. CH 4 conversion of 99.1% in cyclic SESMR operation (10 cycles). H 2 production efficiency of 96.1% (10 cycles) and 97.3% (30 cycles).
As an opportunity for the attenuation of atmospheric CO 2 emissions, conversion of carbon dioxide... more As an opportunity for the attenuation of atmospheric CO 2 emissions, conversion of carbon dioxide into valuable oxygenates as fuel additives or fuel surrogates was explored conceptually in terms of a potentially feasible dimethyl ether (DME) conversion process. Incentives for application of conventional CO 2-DME conversion process are insufficient due to low CO 2 conversion, and DME yield and selectivity. In-situ H 2 O removal by adsorption (sorption-enhanced reaction process) can lead to the displacement of the water gas shift equilibrium and therefore, the enhancement of CO 2 conversion into methanol and the improvement of DME productivity. A two-scale, isothermal, unsteady-state model has been developed to evaluate the performance of a sorption-enhanced DME synthesis reactor. Modeling results show that under H 2 O removal conditions, methanol and DME yields and DME selectivity are favoured and the methanol selectivity decreases. The increase of methanol and DME yields and DME selectivity becomes more important at higher CO 2 feed concentration because a relatively large amount of water is produced followed by a large quantity of water removed from the system. Also, the drop in the fraction of unconverted methanol becomes more important when CO 2 feed concentration is higher and the dehydration reaction is favoured. Therefore, application of the sorption-enhanced reaction concept allows the use of CO 2 as a constituent of the synthesis gas as the in-situ H 2 O removal accelerates the reverse water gas shift reaction.
This work concerns the comparison of the regeneration capability of different single sterically h... more This work concerns the comparison of the regeneration capability of different single sterically hindered alkanolamines (SHA: AMP, AEPD, AMPD, AHPD) or Pz-activated aqueous solutions with that of single MEA aqueous solution. It was found that AEPD, AMPD and AHPD offer an easier and faster regeneration than conventional alkanolamines (MEA). Small additions of Pz to single AHPD aqueous solutions were found to have a beneficial influence on the desorption performance.
The solubility of CO 2 in aqueous solutions of 2-amino-2-hydroxymethyl-1,3-propanediol (AHPD) was... more The solubility of CO 2 in aqueous solutions of 2-amino-2-hydroxymethyl-1,3-propanediol (AHPD) was measured for AHPD mass fractions w = 0.0015, 0.005, 0.01 and 0.025 at 283.15, 298.15 and 313.15 K and for CO 2 partial pressures within 2-75 kPa. These ranges were compatible with aqueous solutions in use in a CO 2 capture process using human carbonic anhydrase metalloenzyme. The influence of carbonic anhydrase on the solubility of CO 2 in AHPD solution with w = 0.025 at 283.15, 298.15 and 313.15 K was also studied for CO 2 partial pressures below 9 kPa. The modified Kent-Eisenberg model was used to correlate the equilibrium solubility of CO 2 in aqueous AHPD solutions and to determine the deprotonation and carbamate stability constants for AHPD solutions. These equilibrium constants were correlated with temperature, amine concentration and CO 2 loading. To estimate the physical solubility of CO 2 in aqueous AHPD solutions, the solubility of N 2 O in aqueous AHPD solutions was also measured for AHPD mass fractions w = 0.0015, 0.005, 0.01, 0.025 and 0.10 at 283.15, 298.15 and 313.15 K. It was found that the enzyme did not influence the solubility of CO 2 in these solutions as the enzyme's function is to catalyze the hydration of CO 2 without affecting the CO 2 thermodynamic equilibrium.
Highlights • Promoted CaO sorbents show high performance over consecutive SESRG/regeneration cycl... more Highlights • Promoted CaO sorbents show high performance over consecutive SESRG/regeneration cycles. • Addition of metal stabilizers improved the hybrid materials stability over cyclic operation. • The integrated process is a promising alternative for single-stage production of high purity hydrogen.
Abstract Bioenergy with carbon capture and storage (BECCS) is gaining increasing attention not on... more Abstract Bioenergy with carbon capture and storage (BECCS) is gaining increasing attention not only as a carbon-neutral alternative to fossil fuels as an energy source, but also as one of the most cost-effective paths to achieve “negative emissions”, which aims at inducing a net emission reduction of atmospheric CO2 with the combined effect of photosynthesis and capture of CO2 emissions. However, like any solution to tackle environmental issues, BECCS has challenges and obstacles to overcome. Concerns over food security, land use, water use, and the feasibility of application at scale have notably been raised and addressing them will be crucial for successful implementation. As an emerging field, active research and development over the next decades, along with strong policy support, is crucial to ensure that BECCS can be implemented in time because delaying action on climate change reduces the likelihood of successfully meeting the goals of the Paris Agreement. Consequently, this critical review aims at establishing the upcoming challenges facing the implementation of BECCS and the pathways to address them, along with highlighting the advancements in the field over the last decade. An overview of the different paths to policy support along with techno-economic analyses of various forms of BECCS is also provided.
Novel Cu–ZnO–ZrO2/UGSO catalysts for CO2 hydrogenation to methanol were developed using a metallu... more Novel Cu–ZnO–ZrO2/UGSO catalysts for CO2 hydrogenation to methanol were developed using a metallurgical residue as catalytic support, focusing on (i) the synergy of Cu/Zn/Zr and UGSO composition and (ii) UGSO modification, on catalytic activity and stability.
Abstract Coal fly ash (FA) supported Ni catalysts (Ni-FA) were synthesized via solid-state impreg... more Abstract Coal fly ash (FA) supported Ni catalysts (Ni-FA) were synthesized via solid-state impregnation method and systematically characterized by XRD, N2-physisorption, H2-TPR/TPD, H2-pulse chemisorption, XPS, TPO, TGA, Raman, and TEM. The effect of different parameters including (i) types of FA, (ii) Ni loading (2.5 - 15 wt.%), and (iii) reforming temperature (530 - 730 ⁰C), on the catalytic performance of yNi-FAx catalysts in glycerol steam reforming was investigated. The best performance in terms of activity (glycerol conversion to gas products = 98 %, H2 yield = 78.8 %) and stability (40 h, with low rate of coke formation and sintering 2.44 mgcoke• g catalyst -1 h-1) was achieved for 7.5%Ni-FA4 catalyst at 630 ⁰C. This was attributed to a higher dispersion of Ni° active sites and stronger interaction with the support, due to the higher surface area of FA4 and the presence of nepheline (providing vacancy sites for anchoring Ni particles) and thermostable mullite.
The sorption-enhanced steam reforming of glycerol (SESRG) is a sustainable approach to produce hi... more The sorption-enhanced steam reforming of glycerol (SESRG) is a sustainable approach to produce high-purity hydrogen in a single step by valorizing waste raw material. Fabricating Ni–CaO-based catal...
The Canadian Journal of Chemical Engineering, 2018
Selective hydroxylation of the C‐H bond of saturated hydrocarbon chains at room temperature is th... more Selective hydroxylation of the C‐H bond of saturated hydrocarbon chains at room temperature is the signature of an invaluable biocatalyst, cytochrome P450 BM3 from Bacillus megaterium. Despite this remarkable ability, because of the enzyme's inherent low stability and dependence on electron supply by expensive NADPH, developing stable and economic BM3 systems is a challenging subject. To improve BM3 stability, facilitate its reuse, and reduce the process cost, this study suggests covalent immobilization of R966D/W1046S P450 BM3 on glutaraldehyde pre‐activated super paramagnetic iron oxide nanoparticles (SPIONs). This double mutant consumes less expensive cofactors like NADH and BNAH and its immobilization on magnetic support facilitates its separation and reuse. Free and immobilized enzyme performances were evaluated by 10‐pNCA hydroxylation and BM3 selectivity (hydroxylation at ω (1–3) positions of a fatty acid) was confirmed in a reaction involving myristic acid. The enzyme ac...
International Journal of Greenhouse Gas Control, 2017
Packed-bed columns with immobilized human carbonic anhydrase II (hCA II) enzyme on fourth generat... more Packed-bed columns with immobilized human carbonic anhydrase II (hCA II) enzyme on fourth generation random packings offer an attractive way to implement CO 2 capture because of low pressure drop, high capacities and extremely large and uniform open area in every ring orientation. Enzyme-based CO 2 removal performance of countercurrent packed-bed column reactors was analyzed by means of a dynamic 3D model which links the macroscopic volume-averaged continuity, momentum and species balance equations in the liquid and gas phases with simultaneous diffusion and chemical reaction at the enzyme washcoat/liquid film scale level. The results reveal that this low-cost, green, and environmentally friendly technology could be an interesting option to CO 2 removal. The performance of packed-bed column reactors with immobilized hCA II enzyme on fourth generation random packings can be enhanced by diminishing the washcoat thickness, increasing the inlet buffer concentration and pK a constant and increasing the liquid velocity conserving a low pressure drop level. Also, operation with extra hCA II loadings allows to obtain higher CO 2 conversion and avoids the deterioration of the CO 2 hydration rate in long-term operation attributable to the decrease of hCA II enzyme activity.
A new membrane preparation method based on mechanical pore-plugging of the supports with appropri... more A new membrane preparation method based on mechanical pore-plugging of the supports with appropriate sized seeds followed by secondary zeolite growth by hydrothermal synthesis was optimized for the production of hydroxy-sodalite (hydroxy-SOD) membranes. A series of parameters were investigated during membrane production, including seed loading, presence of Teflon on the coarse side of the support, top-layer orientation in the autoclave, autoclave agitation, synthesis time and temperature, membrane post-synthesis treatment, and nature and pore size of the support (TiO 2 /SS, SS, Al 2 O 3 and ZrO 2 /TiO 2). Zeolite seeds and synthesized membranes were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and gas permeation. The gas permselective separation ability of these membranes was demonstrated from H 2 , N 2 , CO 2 and H 2 O permeation tests at temperature up to 250 C. The membranes fabricated with the optimized parameters achieved H 2 O/N 2 , H 2 O/CO 2 , and H 2 O/ H 2 ideal gas permselectivities of 5.1, 4.8 and 1.4 at 250 C, while providing a high water permeance (P H2O of 1.26 Â 10 À7 mol Pa À1 m À2 s À1) at the same temperature.
Industrial & Engineering Chemistry Research, 2003
Kinetic study of oxygen-free methane dehydrogenation and aromatization over Ru-Mo/HZSM-5 was carr... more Kinetic study of oxygen-free methane dehydrogenation and aromatization over Ru-Mo/HZSM-5 was carried out in a fixed-bed differential reactor under atmospheric pressure. The reaction temperature was varied between 873 and 973 K, and the methane feed fraction ranged from 50 to 90% v/v. A plausible reaction pathway involved in oxygen-free methane dehydrogenation and aromatization over Ru-Mo/HZSM-5 was proposed. Different models based on Langmuir-Hinshelwood-Hougen-Watson reaction mechanisms were tested to correlate the kinetic data. Among these models, the one postulating that the surface dehydrogenation reaction of adsorbed methane is rate-determining was successful in terms of physical likeliness (thermodynamic and kinetic parameters) and statistical goodness of fit. The activation energy, adsorption enthalpy, and entropy frequency were evaluated by means of Arrhenius or Van't Hoff relationships.
The effect of lithium chloride LiCl at salt mole fractions from 0.005 to 0.15 and at saturation o... more The effect of lithium chloride LiCl at salt mole fractions from 0.005 to 0.15 and at saturation on Ž. vapor-liquid equilibrium VLE of the binary acetone-methanol system has been experimentally investigated at 101.32 kPa using a modified Othmer equilibrium still, in order to elucidate the behavior of this mixture whose existing data are rather contradictory. The salting-out effect of the salt on the VLE of the mixed solvent was explained by the preferential solvation theory. The experimental data were correlated by the electrolytic NRTL Ž. model of Mock et al. 1986. The mean absolute deviations of the correlation for y and T are 0.018 and 0.74 K, respectively.
Al-stabilized CaO-nickel hybrid sorbent-catalyst prepared by limestone acidification. The hybrid ... more Al-stabilized CaO-nickel hybrid sorbent-catalyst prepared by limestone acidification. The hybrid sorbent-catalyst with 25 wt% NiO provided the best results. CH 4 conversion of 99.1% in cyclic SESMR operation (10 cycles). H 2 production efficiency of 96.1% (10 cycles) and 97.3% (30 cycles).
As an opportunity for the attenuation of atmospheric CO 2 emissions, conversion of carbon dioxide... more As an opportunity for the attenuation of atmospheric CO 2 emissions, conversion of carbon dioxide into valuable oxygenates as fuel additives or fuel surrogates was explored conceptually in terms of a potentially feasible dimethyl ether (DME) conversion process. Incentives for application of conventional CO 2-DME conversion process are insufficient due to low CO 2 conversion, and DME yield and selectivity. In-situ H 2 O removal by adsorption (sorption-enhanced reaction process) can lead to the displacement of the water gas shift equilibrium and therefore, the enhancement of CO 2 conversion into methanol and the improvement of DME productivity. A two-scale, isothermal, unsteady-state model has been developed to evaluate the performance of a sorption-enhanced DME synthesis reactor. Modeling results show that under H 2 O removal conditions, methanol and DME yields and DME selectivity are favoured and the methanol selectivity decreases. The increase of methanol and DME yields and DME selectivity becomes more important at higher CO 2 feed concentration because a relatively large amount of water is produced followed by a large quantity of water removed from the system. Also, the drop in the fraction of unconverted methanol becomes more important when CO 2 feed concentration is higher and the dehydration reaction is favoured. Therefore, application of the sorption-enhanced reaction concept allows the use of CO 2 as a constituent of the synthesis gas as the in-situ H 2 O removal accelerates the reverse water gas shift reaction.
This work concerns the comparison of the regeneration capability of different single sterically h... more This work concerns the comparison of the regeneration capability of different single sterically hindered alkanolamines (SHA: AMP, AEPD, AMPD, AHPD) or Pz-activated aqueous solutions with that of single MEA aqueous solution. It was found that AEPD, AMPD and AHPD offer an easier and faster regeneration than conventional alkanolamines (MEA). Small additions of Pz to single AHPD aqueous solutions were found to have a beneficial influence on the desorption performance.
The solubility of CO 2 in aqueous solutions of 2-amino-2-hydroxymethyl-1,3-propanediol (AHPD) was... more The solubility of CO 2 in aqueous solutions of 2-amino-2-hydroxymethyl-1,3-propanediol (AHPD) was measured for AHPD mass fractions w = 0.0015, 0.005, 0.01 and 0.025 at 283.15, 298.15 and 313.15 K and for CO 2 partial pressures within 2-75 kPa. These ranges were compatible with aqueous solutions in use in a CO 2 capture process using human carbonic anhydrase metalloenzyme. The influence of carbonic anhydrase on the solubility of CO 2 in AHPD solution with w = 0.025 at 283.15, 298.15 and 313.15 K was also studied for CO 2 partial pressures below 9 kPa. The modified Kent-Eisenberg model was used to correlate the equilibrium solubility of CO 2 in aqueous AHPD solutions and to determine the deprotonation and carbamate stability constants for AHPD solutions. These equilibrium constants were correlated with temperature, amine concentration and CO 2 loading. To estimate the physical solubility of CO 2 in aqueous AHPD solutions, the solubility of N 2 O in aqueous AHPD solutions was also measured for AHPD mass fractions w = 0.0015, 0.005, 0.01, 0.025 and 0.10 at 283.15, 298.15 and 313.15 K. It was found that the enzyme did not influence the solubility of CO 2 in these solutions as the enzyme's function is to catalyze the hydration of CO 2 without affecting the CO 2 thermodynamic equilibrium.
Highlights • Promoted CaO sorbents show high performance over consecutive SESRG/regeneration cycl... more Highlights • Promoted CaO sorbents show high performance over consecutive SESRG/regeneration cycles. • Addition of metal stabilizers improved the hybrid materials stability over cyclic operation. • The integrated process is a promising alternative for single-stage production of high purity hydrogen.
Abstract Bioenergy with carbon capture and storage (BECCS) is gaining increasing attention not on... more Abstract Bioenergy with carbon capture and storage (BECCS) is gaining increasing attention not only as a carbon-neutral alternative to fossil fuels as an energy source, but also as one of the most cost-effective paths to achieve “negative emissions”, which aims at inducing a net emission reduction of atmospheric CO2 with the combined effect of photosynthesis and capture of CO2 emissions. However, like any solution to tackle environmental issues, BECCS has challenges and obstacles to overcome. Concerns over food security, land use, water use, and the feasibility of application at scale have notably been raised and addressing them will be crucial for successful implementation. As an emerging field, active research and development over the next decades, along with strong policy support, is crucial to ensure that BECCS can be implemented in time because delaying action on climate change reduces the likelihood of successfully meeting the goals of the Paris Agreement. Consequently, this critical review aims at establishing the upcoming challenges facing the implementation of BECCS and the pathways to address them, along with highlighting the advancements in the field over the last decade. An overview of the different paths to policy support along with techno-economic analyses of various forms of BECCS is also provided.
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Papers by Maria Iliuta