The Experts below are selected from a list of 111 Experts worldwide ranked by ideXlab platform
Charles Q. Jia - One of the best experts on this subject based on the ideXlab platform.
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Isolating the effect of pore size distribution on electrochemical double-layer capacitance using activated Fluid Coke
Journal of Power Sources, 2015Co-Authors: Jocelyn E. Zuliani, Donald W. Kirk, Shitang Tong, Charles Q. JiaAbstract:Abstract Electrochemical double-layer capacitors (EDLCs) use physical ion adsorption in the capacitive electrical double layer of high specific surface area (SSA) materials to store electrical energy. Previous work shows that the SSA-normalized capacitance increases when pore diameters are less than 1 nm. However, there still remains uncertainty about the charge storage mechanism since the enhanced SSA-normalized capacitance is not observed in all microporous materials. In previous studies, the total specific surface area and the chemical composition of the electrode materials were not controlled. The current work is the first reported study that systematically compares the performance of activated carbon prepared from the same raw material, with similar chemical composition and specific surface area, but different pore size distributions. Preparing samples with similar SSAs, but different pores sizes is not straightforward since increasing pore diameters results in decreasing the SSA. This study observes that the microporous activated carbon has a higher SSA-normalized capacitance, 14.1 μF cm −2 , compared to the mesoporous material, 12.4 μF cm −2 . However, this enhanced SSA-normalized capacitance is only observed above a threshold operating voltage. Therefore, it can be concluded that a minimum applied voltage is required to induce ion adsorption in these sub-nanometer micropores, which increases the capacitance.
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Activated oil sands Fluid Coke for electrical double-layer capacitors
Journal of Power Sources, 2014Co-Authors: Jocelyn E. Zuliani, Donald W. Kirk, Charles Q. Jia, Shitang TongAbstract:Abstract Electrochemical capacitors are important energy storage devices that have high power density, rapid charging cycles and are highly cyclable. In this study, activated Fluid Coke has demonstrated high surface area, improved capacitive properties, and high energy density. Fluid Coke is a by-product generated from continuous high temperature bitumen upgrading, resulting in the formation of nearly spherical particles with concentric carbon layers. The residual sulphur impurities in Fluid Coke may enhance its energy storage performance. The activated Coke samples have high specific surface areas, up to 1960 m2 g−1, and show promising capacitive performance, in 4 M KOH electrolyte, with high gravimetric and specific capacitances of 228–257 F g−1 and 13–14 μF cm−2, respectively. These results are comparable to other top performing activated carbon materials [1–3]. The activated Fluid Coke maintains high performance at fast charging rates, greater than 160 F g−1 at a current density of 7500 mA g−1. Activated Fluid Coke's high capacitance and promising rate performance are potentially associated with its unique layered, and the moderate sulphur content in the chemical structure. Activated Fluid Coke is a unique opportunity to use a limited use by-product to generate activated carbon that has a high surface area and promising energy storage properties.
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Effects of Temperature on Electrochemical Double Layer Capacitor Performance Using Activated Carbon Electrodes
2013Co-Authors: Jocelyn E. Zuliani, Charles Q. Jia, Mehzabeen Zereen, Donald W. KirkAbstract:Activated carbon (AC) has received considerable interest as a possible electrode material for electrochemical double layer capacitors (EDLC). AC is a highly porous carbonaceous material which presents very high specific surface area and good conductivity making it ideally suited for an EDLC electrode. Two types of AC were used in this analysis, the first was generated from waste petroleum Fluid Coke through chemical activation using potassium hydroxide and the second was coconut shell derived AC generated with CO2 activation. The electrodes were fabricated using 90 wt% AC, 6 wt% carbon black and 4 wt% PTFE.
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Mercury Removal from Aqueous Solution Using Coke-Derived Sulfur-Impregnated Activated Carbons
Industrial & Engineering Chemistry Research, 2010Co-Authors: Jenny H. Cai, Charles Q. JiaAbstract:Sulfur-impregnated activated carbons (SIACs) produced from oil-sands Fluid Coke by KOH−SO2 activation were applied to remove mercury ions from aqueous solutions. A pseudo-first-order rate expressio...
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Sulfur speciation in Fluid Coke and its activation products using K-edge X-ray absorption near edge structure spectroscopy
Journal of Sulfur Chemistry, 2009Co-Authors: Jenny H. Cai, Eric A. Morris, Charles Q. JiaAbstract:Fluid Coke is a by-product of bitumen upgrading process and a stockpiled industrial waste produced in large quantities in Alberta, Canada (overall 10,000 tonnes per day). It has been used as a raw material for manufacturing sulfur-impregnated activated carbon (SIAC). Properties of sulfur in the SIAC are critical to the effectiveness of SIAC in adsorbing mercury at ppb levels. K-edge X-ray absorption near edge structure (XANES) spectroscopy was employed to characterize sulfur in two Fluid Coke samples and their activation products. It was found that about 90% of sulfur in two Coke samples is of organic nature, with over 50% of sulfur in the form of thiophene and the rest 40% being organic sulfide. About 10% of sulfur is in the form of oxides, i.e. sulfate. To simulate the Coke samples and validate the analytical technique, a mixture of pure sulfur compounds and graphite was prepared and examined with XANES; the results showed good agreement between the actual and measured sulfur contents in specific forms....
John R. Grace - One of the best experts on this subject based on the ideXlab platform.
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from fossil fuels towards renewables inhibitory and catalytic effects on carbon thermochemical conversion during co gasification of biomass with fossil fuels
Applied Energy, 2015Co-Authors: Mohammad S Masnadi, John R. Grace, Xiaotao Bi, Naoko EllisAbstract:Recent environmental regulatory sharp curbs on fossil fuel power plants have obliged industries to incorporate alternative sources of fuels for energy production. Cost and recovery of synthetic catalysts are major challenges in carbonaceous materials catalytic gasification. Biomass rich in alkali metals can be added as fuel and also to provide inexpensive natural catalysts to boost fossil fuel gasification. Biomass/fossil fuel co-gasification could provide bridging energy production based on renewable and fossil fuels. In this work, CO2 co-gasification of switchgrass and sawdust with coal and Fluid Coke was conducted in a thermogravimetric analyzer. Gasification kinetics were inhibited or enhanced, depending on the potassium concentration in the mixture. For low K/Al and K/Si molar ratios, the coal ash sequestered the biomass potassium needed for KAlSiO4 formation, and thus, no catalytic effect was observed until the biomass-to-coal mass ratio reached 3:1, where the switchgrass ash supplied enough potassium to more than satisfy the minerals in the coal ash. For high K/Al and K/Si molar ratios, unreacted residual potassium acted as catalyst, enhancing coal gasification. Fluid Coke contained much lower Al and Si than for the coal. Hence, the gasification kinetics of Fluid Coke were significantly augmented by blending the Coke with switchgrass due to the abundance of potassium in the biomass.
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fuel characterization and co pyrolysis kinetics of biomass and fossil fuels
Fuel, 2014Co-Authors: Mohammad S Masnadi, Rozita Habibi, Jan Kopyscinski, Josephine M Hill, Naoko Ellis, Jim C Lim, John R. GraceAbstract:Abstract It is not well understood how co-feeding of coal and biomass influences the reaction kinetics of gasification and pyrolysis. Co-pyrolysis of biomass and fossil fuels is investigated in this paper. After fuel characterization, the influences of temperature on the physical and chemical properties of char produced from biomass and non-biomass fuels were investigated, and the kinetics of atmospheric-pressure pyrolysis in a nitrogen environment were determined. The results show that product physical properties, such as surface area, depend on the pyrolysis temperature. For individual fuels, pine sawdust char prepared at 750 °C had the highest CO 2 and N 2 uptake, while switchgrass had very low N 2 uptake, but high CO 2 uptake. The surface area of the Fluid Coke decreased with increasing temperature, but was almost constant for coal. Co-pyrolysis in a thermogravimetric analyzer exhibited three stages. Devolatilization of the biomass and coal portions of blended samples occurred independently, i.e. without significant synergy. The Coats–Redfern method was used to analyze the kinetics of solid fuel pyrolysis, indicating that it can be described by multi-step reactions. The model was able to identify likely reaction mechanisms and activation energies of each pyrolysis stage, giving predictions consistent with the experimental results.
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co gasification of biomass and non biomass feedstocks synergistic and inhibition effects of switchgrass mixed with sub bituminous coal and Fluid Coke during co2 gasification
Energy & Fuels, 2013Co-Authors: Rozita Habibi, Jan Kopyscinski, Mohammad S Masnadi, Cedric A. Mims, John R. Grace, Josephine M HillAbstract:Co-gasification of biomass, namely, switchgrass, with coal and Fluid Coke was performed to investigate the availability of the gasification catalysts to the mixed feedstock, especially alkali and alkaline earth elements, naturally present on switchgrass. Rates of CO2 gasification of the single and mixed materials were measured at temperatures between 750 and 950 °C and atmospheric pressure by thermogravimetry. High interparticle mobility of the catalysts is indicated by a prompt and lasting effect on the mixed feed gasification rate when compared with the separate rates. The switchgrass–coal mixtures show a deactivation (antagonism), attributed to sequestration of the mobile alkali elements by reaction with aluminosilicate minerals in coal to form inactive alkali aluminosilicates, such as KAlSi3O8 and KAlSiO4. Remaining catalytic activity is evident when excess alkali is present in the feed mixture to satisfy the stoichiometric requirements of these deactivation reactions. In co-gasification of switchgras...
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Experimental Simulation of the Reactor Section of Fluid Cokers: Comparison of FCC and Fluid Coke Particles
The Canadian Journal of Chemical Engineering, 2008Co-Authors: Xuqi Song, John R. Grace, C. Jim Lim, Edward Chan, Brian Knapper, Craig A. McknightAbstract:The hydrodynamics of Fluid Cokers were studied in a pressurized fully cylindrical cold model of diameter 483 mm, geometrically and dynamically scaled down by a factor of ∼20 from commercial units. Differential pressure fluctuations, voidage distributions, solids momentum flux distributions and steady state gas mixing behaviour in the reactor section are compared for the same operating conditions with two kinds of particles, FCC and Fluid Coke. The voidage distributions and core-annular flow structures in the reactor section were similar enough that either FCC or Fluid Coke particles can be used for cold modelling of Fluid Cokers. On a etudie l'hydrodynamique d'unites de Cokefaction Fluide dans une maquette froide cylindrique pressurisee de 483 mm de diametre, geometriquement et dynamiquement reduite d'un facteur 20 par rapport a des unites commerciales. Les fluctuations de pression differentielles, les distributions de vide, les distributions de flux de moment des solides et le comportement de melange de gaz a l'etat stable dans la section du reacteur sont compares pour les memes conditions operatoires avec deux sortes de particules, soient FCC et Coke Fluide. Les distributions de vide et les structures d'ecoulement noyau-espace annulaire dans la section du reacteur sont suffisamment semblables pour que des particules de FCC ou de Coke Fluide puissent etre utilisees pour la modelisation a froid d'unites de Cokefaction Fluide.
Mohammad S Masnadi - One of the best experts on this subject based on the ideXlab platform.
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from fossil fuels towards renewables inhibitory and catalytic effects on carbon thermochemical conversion during co gasification of biomass with fossil fuels
Applied Energy, 2015Co-Authors: Mohammad S Masnadi, John R. Grace, Xiaotao Bi, Naoko EllisAbstract:Recent environmental regulatory sharp curbs on fossil fuel power plants have obliged industries to incorporate alternative sources of fuels for energy production. Cost and recovery of synthetic catalysts are major challenges in carbonaceous materials catalytic gasification. Biomass rich in alkali metals can be added as fuel and also to provide inexpensive natural catalysts to boost fossil fuel gasification. Biomass/fossil fuel co-gasification could provide bridging energy production based on renewable and fossil fuels. In this work, CO2 co-gasification of switchgrass and sawdust with coal and Fluid Coke was conducted in a thermogravimetric analyzer. Gasification kinetics were inhibited or enhanced, depending on the potassium concentration in the mixture. For low K/Al and K/Si molar ratios, the coal ash sequestered the biomass potassium needed for KAlSiO4 formation, and thus, no catalytic effect was observed until the biomass-to-coal mass ratio reached 3:1, where the switchgrass ash supplied enough potassium to more than satisfy the minerals in the coal ash. For high K/Al and K/Si molar ratios, unreacted residual potassium acted as catalyst, enhancing coal gasification. Fluid Coke contained much lower Al and Si than for the coal. Hence, the gasification kinetics of Fluid Coke were significantly augmented by blending the Coke with switchgrass due to the abundance of potassium in the biomass.
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fuel characterization and co pyrolysis kinetics of biomass and fossil fuels
Fuel, 2014Co-Authors: Mohammad S Masnadi, Rozita Habibi, Jan Kopyscinski, Josephine M Hill, Naoko Ellis, Jim C Lim, John R. GraceAbstract:Abstract It is not well understood how co-feeding of coal and biomass influences the reaction kinetics of gasification and pyrolysis. Co-pyrolysis of biomass and fossil fuels is investigated in this paper. After fuel characterization, the influences of temperature on the physical and chemical properties of char produced from biomass and non-biomass fuels were investigated, and the kinetics of atmospheric-pressure pyrolysis in a nitrogen environment were determined. The results show that product physical properties, such as surface area, depend on the pyrolysis temperature. For individual fuels, pine sawdust char prepared at 750 °C had the highest CO 2 and N 2 uptake, while switchgrass had very low N 2 uptake, but high CO 2 uptake. The surface area of the Fluid Coke decreased with increasing temperature, but was almost constant for coal. Co-pyrolysis in a thermogravimetric analyzer exhibited three stages. Devolatilization of the biomass and coal portions of blended samples occurred independently, i.e. without significant synergy. The Coats–Redfern method was used to analyze the kinetics of solid fuel pyrolysis, indicating that it can be described by multi-step reactions. The model was able to identify likely reaction mechanisms and activation energies of each pyrolysis stage, giving predictions consistent with the experimental results.
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co gasification of biomass and non biomass feedstocks synergistic and inhibition effects of switchgrass mixed with sub bituminous coal and Fluid Coke during co2 gasification
Energy & Fuels, 2013Co-Authors: Rozita Habibi, Jan Kopyscinski, Mohammad S Masnadi, Cedric A. Mims, John R. Grace, Josephine M HillAbstract:Co-gasification of biomass, namely, switchgrass, with coal and Fluid Coke was performed to investigate the availability of the gasification catalysts to the mixed feedstock, especially alkali and alkaline earth elements, naturally present on switchgrass. Rates of CO2 gasification of the single and mixed materials were measured at temperatures between 750 and 950 °C and atmospheric pressure by thermogravimetry. High interparticle mobility of the catalysts is indicated by a prompt and lasting effect on the mixed feed gasification rate when compared with the separate rates. The switchgrass–coal mixtures show a deactivation (antagonism), attributed to sequestration of the mobile alkali elements by reaction with aluminosilicate minerals in coal to form inactive alkali aluminosilicates, such as KAlSi3O8 and KAlSiO4. Remaining catalytic activity is evident when excess alkali is present in the feed mixture to satisfy the stoichiometric requirements of these deactivation reactions. In co-gasification of switchgras...
Naoko Ellis - One of the best experts on this subject based on the ideXlab platform.
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from fossil fuels towards renewables inhibitory and catalytic effects on carbon thermochemical conversion during co gasification of biomass with fossil fuels
Applied Energy, 2015Co-Authors: Mohammad S Masnadi, John R. Grace, Xiaotao Bi, Naoko EllisAbstract:Recent environmental regulatory sharp curbs on fossil fuel power plants have obliged industries to incorporate alternative sources of fuels for energy production. Cost and recovery of synthetic catalysts are major challenges in carbonaceous materials catalytic gasification. Biomass rich in alkali metals can be added as fuel and also to provide inexpensive natural catalysts to boost fossil fuel gasification. Biomass/fossil fuel co-gasification could provide bridging energy production based on renewable and fossil fuels. In this work, CO2 co-gasification of switchgrass and sawdust with coal and Fluid Coke was conducted in a thermogravimetric analyzer. Gasification kinetics were inhibited or enhanced, depending on the potassium concentration in the mixture. For low K/Al and K/Si molar ratios, the coal ash sequestered the biomass potassium needed for KAlSiO4 formation, and thus, no catalytic effect was observed until the biomass-to-coal mass ratio reached 3:1, where the switchgrass ash supplied enough potassium to more than satisfy the minerals in the coal ash. For high K/Al and K/Si molar ratios, unreacted residual potassium acted as catalyst, enhancing coal gasification. Fluid Coke contained much lower Al and Si than for the coal. Hence, the gasification kinetics of Fluid Coke were significantly augmented by blending the Coke with switchgrass due to the abundance of potassium in the biomass.
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fuel characterization and co pyrolysis kinetics of biomass and fossil fuels
Fuel, 2014Co-Authors: Mohammad S Masnadi, Rozita Habibi, Jan Kopyscinski, Josephine M Hill, Naoko Ellis, Jim C Lim, John R. GraceAbstract:Abstract It is not well understood how co-feeding of coal and biomass influences the reaction kinetics of gasification and pyrolysis. Co-pyrolysis of biomass and fossil fuels is investigated in this paper. After fuel characterization, the influences of temperature on the physical and chemical properties of char produced from biomass and non-biomass fuels were investigated, and the kinetics of atmospheric-pressure pyrolysis in a nitrogen environment were determined. The results show that product physical properties, such as surface area, depend on the pyrolysis temperature. For individual fuels, pine sawdust char prepared at 750 °C had the highest CO 2 and N 2 uptake, while switchgrass had very low N 2 uptake, but high CO 2 uptake. The surface area of the Fluid Coke decreased with increasing temperature, but was almost constant for coal. Co-pyrolysis in a thermogravimetric analyzer exhibited three stages. Devolatilization of the biomass and coal portions of blended samples occurred independently, i.e. without significant synergy. The Coats–Redfern method was used to analyze the kinetics of solid fuel pyrolysis, indicating that it can be described by multi-step reactions. The model was able to identify likely reaction mechanisms and activation energies of each pyrolysis stage, giving predictions consistent with the experimental results.
Keng H. Chung - One of the best experts on this subject based on the ideXlab platform.
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Mechanistic Study of the Carbothermal Reduction of Sulfur Dioxide with Oil Sand Fluid Coke
Industrial & Engineering Chemistry Research, 2003Co-Authors: Cesar Bejarano, Charles Q. Jia, Keng H. ChungAbstract:Carbothermal reduction is a reducing reaction involving carbonaceous materials at high temperatures. Oil sand Fluid Coke is a high-carbon byproduct of the thermal cracking of oil sand bitumen via a process called Fluid coking. To lay a foundation for the development of a process that removes and converts sulfur dioxide into elemental sulfur, the kinetics of the carbothermal reduction of SO2 by Coke at 700−950 °C was investigated using a packed-bed reactor. Analysis using the shrinking core model revealed that the overall process is controlled jointly by surface chemical reaction and diffusion in a product ash layer. The existence of the layer was confirmed by SEM examination of a cross section of spent Coke particles. The activation energy of the overall reaction was found to be 154 kJ/mol, which is in a good agreement with literature values. The sulfur balance was analyzed with data obtained using a total sulfur analyzer and a gas chromatograph. SEM-EDS analysis indicated that the ash layer was low in su...
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A study on carbothermal reduction of sulfur dioxide to elemental sulfur using oilsands Fluid Coke.
Environmental science & technology, 2001Co-Authors: Cesar A. Bejarano, Charles Q. Jia, Keng H. ChungAbstract:Experiments and reaction equilibrium calculations were carried out for the SO2 gas and oilsands Fluid Coke system. The goal was to develop a Coke-based sulfur-producing flue gas desulfurization (SP...