Morris Argyle - Academia.edu (original) (raw)

Papers by Morris Argyle

Hydrogen sulfide (H2S) decomposition was carried out in each of four balance gases (Ar, He, N2 an... more Hydrogen sulfide (H2S) decomposition was carried out in each of four balance gases (Ar, He, N2 and H2) in a wire-in-tube pulsed corona discharge reactor. H2S conversion rates and H2S decomposition energy efficiencies depend on the balance gas and H2S concentrations. H2S conversion in monatomic balance gases, like Ar and He, is more efficient than in diatomic balance gases like

The catalytic properties of Al2O3-supported vanadia with a wide range of VOx surface density (1.4... more The catalytic properties of Al2O3-supported vanadia with a wide range of VOx surface density (1.4-34.2 V/nm2) and structure were examined for the oxidative dehydrogenation of ethane and propane. UV-visible and Raman spectra showed that vanadia is dispersed predominantly as isolated monovanadate species below â2.3 V/nm2. As surface densities increase, two-dimensional polyvanadates appear (2.3-7.0 V/nm2) along with increasing amounts of V2O5

Applied Energy, 2015

Iron catalyst was reduced to metallic iron in coal pyrolysis. SEM and EDS images shows the cataly... more Iron catalyst was reduced to metallic iron in coal pyrolysis. SEM and EDS images shows the catalytic effect of iron on char gasification. The shrinking core model is more suitable than the random pore model for this work. The catalytic iron species were initially the metallic iron and FeO, and then changed to FeO and Fe 3 O 4 . g r a p h i c a l a b s t r a c t SEM images of the char sample and the corresponding distribution of iron atom clusters from EDS. a b s t r a c t CO 2 gasification of a sub-bituminous Wyodak coal from the Powder River Basin (PRB) was conducted in a fixed-bed laboratory gasifier at atmospheric pressure with FeCO 3 as a catalyst precursor. The effect of iron on the coal pyrolysis was evaluated by thermo-gravimetric analysis (TGA). Scanning electron microscopy (SEM) was employed to characterize the iron performance in the char gasification. The iron species and oxidation states during the coal gasification, characterized by X-ray diffraction (XRD) and Mössbauer spectroscopy, indicate a complex interaction between the reaction atmosphere and temperature, but generally proceed through reduction to FeO and metallic iron during pyrolysis, followed by subsequent reoxidation to Fe 3 O 4 during gasification with CO 2 . The catalytic effect of iron was also quantitatively evaluated by kinetic analysis using shrinking core and random pore models, with the shrinking core model providing superior results. Results show that the apparent activation energy was 92.7 kJ/mol for the untreated coal, which decreased to 58.3 kJ/mol for the coal with 3 wt% Fe. FeCO 3 was shown to have a significant catalytic effect on the Wyodak coal gasification with CO 2 .

A series of cobalt oxide catalysts supported on alumina (Î³-AlâOâ) were synthesized with varying ... more A series of cobalt oxide catalysts supported on alumina (Î³-AlâOâ) were synthesized with varying contents of cobalt and of added alkali metals, including lithium, sodium, potassium, rubidium, and cesium. Unsupported cobalt oxide catalysts and several cobalt oxide catalysts supported ceria (CeOâ) with varying contents of cobalt with added potassium were also prepared. The catalysts were characterized with UV-visible spectroscopy and were examined for NOâ decomposition activity. The CoOâ/AlâOâ catalysts and particularly the CoOâ/CeOâ catalysts show NâO decomposition activity, but none of the catalysts (unsupported CoâOâ or those supported on ceria or alumina) displayed significant, sustained NO decomposition activity. For the AlâOâ-supported catalysts, NâO decomposition activity was observed over a range of reaction temperatures beginning about 723 K, but significant (>50%) conversions of NâO were observed only for reaction temperatures >900 K, which are too high for practical commercial use. However, the CeOâ-supported catalysts display NâO decomposition rates similar to the AlâOâ-supported catalysts at much lower reaction temperatures, with activity beginning at â573 K. Conversions of >90% were achieved at 773 K for the best catalysts. Catalytic rates per cobalt atom increased with decreasing cobalt content, which corresponds to increasing edge energies obtained from the UV-visible spectra. The decrease in edge energies suggests that the size and dimensionality of the cobalt oxide surface domains increase with increasing cobalt oxide content. The rate data normalized per mass of catalyst that shows the activity of the CeOâ-supported catalysts increases with increasing cobalt oxide content. The combination of these data suggest that supported cobalt oxide species similar to bulk CoâOâ are inherently more active than more dispersed cobalt oxide species, but this effect was only observed with the CeOâ-supported catalysts.

Catal. Sci. Technol., 2014

investigates the effects of various, carefully-chosen preparation methods on the performance of F... more investigates the effects of various, carefully-chosen preparation methods on the performance of Fischer-Tropsch (FT) alumina-supported iron/copper/potassium (FeCuK/Al 2 O 3 ) catalysts.

The present invention generally relates to a catalytic gasification of coal. Catalytic gasificati... more The present invention generally relates to a catalytic gasification of coal. Catalytic gasification of a Wyodak low-sulfur sub-bituminous coal from the Powder River Basin of Wyoming was investigated using an inexpensive sodium carbonate catalyst applied via incipient wetness impregnation. Experiments in an atmospheric pressure fixed-bed laboratory gasifier were performed to evaluate the effects of reaction temperature, feed gas steam content, and Na2CO3 loading on the catalytic gasification of the Wyodak coal. The temperature range investigated (700-900°C) was selected with consideration of the Na2CO3 melting point (850°C) to reduce the loss by volatilization of sodium. Sodium was found to be active during both pyrolysis and gasification steps. The catalyst was most cost-effective at addition levels of approximately 3 wt%. The random pore model provided a good fit to the conversion versus time data collected under both the catalytic and the uncatalytic conditions.

The objective of this research is to study the composite effect of FeCO3 and Na2CO3 catalysts on ... more The objective of this research is to study the composite effect of FeCO3 and Na2CO3 catalysts on gasification of a low- sulfur sub- bituminous Wyodak coal from the Powder River Basin (PRB) of Wyoming. The catalytic effects of the composite material were evaluated by comparing the effluent gas and carbon conversion kinetics of pure FeCO3 and Na2CO3 catalysts with the composite catalysts. A fixed bed gasifier was used in a steam environment to gasify the coal at atm. pressure. Surface area tests were used to characterize the materials. The results demonstrated that sodium /iron composite catalysts used for coal gasification are more efficient at increasing conversion rates, reducing the reaction activation energy, lowering the required gasification temp. for a given level of conversion, and producing higher yields of the gases that preserve the highest heat of combustion compared to the pure iron or the pure sodium catalysts. This study shows that the use of composite FeCO3 and Na2CO3...

Coal is the major source of fuel for generation of electricity in the United States and provides ... more Coal is the major source of fuel for generation of electricity in the United States and provides about 48.5% of the total electric power generated. Increasing anthropogenic carbon dioxide (CO2) levels as a consequence of burning fossil fuels are raising concerns over global warming and climate change. The amount of CO2 produced from the combustion of fossil fuels in the United States will reach nearly 5.7 billion metric tons in 2009 according to EIA, with about 33% coming from the coal-fired electric power sector. As a result, carbon capture and storage (CCS) technologies that are stable, safe, economically feasible, and environmentally acceptable are required to sustain the coal industry and to minimize CO2 emissions. Accelerated mineral carbonation (AMC) process for simultaneous capture and mineralization of flue gas CO2 was tested at one of the largest pulverized coal power plants in the US (Jim Bridger Power Plant, Point of Rocks, WY). The process consists of three vessels- a mo...

Catalysts, 2015

Deactivation of heterogeneous catalysts is a ubiquitous problem that causes loss of catalytic rat... more Deactivation of heterogeneous catalysts is a ubiquitous problem that causes loss of catalytic rate with time. This review on deactivation and regeneration of heterogeneous catalysts classifies deactivation by type (chemical, thermal, and mechanical) and by mechanism (poisoning, fouling, thermal degradation, vapor formation, vapor-solid and solid-solid reactions, and attrition/crushing). The key features and considerations for each of these deactivation types is reviewed in detail with reference to the latest literature reports in these areas. Two case studies on the deactivation mechanisms of catalysts used for cobalt Fischer-Tropsch and selective catalytic reduction are considered to provide additional depth in the topics of sintering, coking, poisoning, and fouling. Regeneration considerations and options are also briefly discussed for each deactivation mechanism.

International Journal of Hydrogen Energy, 2014

Hydrogen Methanation a b s t r a c t

Minerals, 2014

Globally, coal-fired power plants are the largest industrial source of carbon dioxide (CO 2 ). CO... more Globally, coal-fired power plants are the largest industrial source of carbon dioxide (CO 2 ). CO 2 emissions from flue gas have potential for direct mineralization with electrostatic precipitator fly ash particles in the field. Demonstration scale accelerated mineral carbonation (AMC) studies were conducted at the Jim Bridger Power Plant, a large coal fired power plant located in Wyoming, USA. AMC produces kinetically rapid conditions for increased rates of mineralization of CO 2 , sulfur dioxide (SO 2 ) and mercury (Hg) on fly ash particles. Control and AMC reacted fly ash particles were investigated for: change in carbon (expressed as CaCO 3 ), sulfur (expressed as SO 4 2− ), and mercury (Hg) contents; topology and surface chemical composition by scanning electron microscope/energy dispersive X-ray spectroscopy analysis; chemical distribution of trace elements; and aqueous mineral solubility by the toxicity characteristic leaching procedure. Results of the AMC process show an increase in C, S, and Hg on AMC fly ash particles suggesting that multiple pollutants from flue gas can be removed through this direct mineral carbonation process. Results also suggest that the AMC process shifts soluble trace elements in fly ash to less leachable mineral fractions. The results of this study can provide insight into potential successful field implementation of AMC.

IOP Conference Series: Earth and Environmental Science, 2009