Investigation into the Effect of Various Metals\u27 Ionic Charge and Size on their Mobility under the Influence of Electrokinetics

This research investigates the effect of ionic charge and size on the mobility of specific metal ionic species in sandy soil under an electric field. During Phase-I experiments, three ions: lithium, lead and, aluminum were initially selected for study. Since the resistance of the cell varied with time, power could not be maintained constant. Therefore, a numerical integration technique was adopted to compare the results. These results show that the mobility of the ions increased with the increase in valence of the ions (for lithium and lead). However, aluminum interacted with and adsorbed to sand. To overcome this problem, aluminum spiked sand was used for Phase-II testing. During this phase, lithium, lead, and yttrium ions were evaluated. These results suggest that the mobility of the ions increased with increase in valence of the ions (Y \u3e Pb \u3eLi). However, ionic size did not have a substantial effect on the ionic movement

Biomass Gasification: Catalytic Steam Reforming of Tars Using Nickel Supported Zeolites and Montmorillonite

Tars have been identified as one of the major impurities associated with the utilization of biomass gasification fuel gas. Tars may result in blockages, plugging, corrosion and catalyst deactivation, leading to serious operational and maintenance problems during biomass gasification. Therefore, tar removal is essential to insure economic and effective fuel gas utilization. This study investigates the catalytic activity of zeolites, and nickel-supported zeolites for tar removal. Tests were conducted using a bench scale reactor and naphthalene as a model tar compound. Zeolites with varying pore sizes and acidity were tested to evaluate the effect of pore size and acidity on tar removal. Test results suggested that the catalytic activity increased with an increase in pore size and the number of acidic sites on the zeolite. The steam reforming ability of nickel towards naphthalene removal was evaluated by impregnating nickel on zeolites; this impregnation improved the activity of the catalysts significantly. Long term catalytic activity tests were performed, which showed that nickel supported ZY-30 and ZY-80 had the best naphthalene conversion, with naphthalene conversions of greater than 99%, followed by nickel- supported ZY-5.2, SiO2/Al2O3, and chabazite, respectively. This study also evaluated the catalytic activity of montmorillonite and nickel- supported montmorillonite as tar removal catalysts. Montmorillonite, and Ni-montmorillonite were tested for their efficiency in reforming tars. Also, the efficacy of nickel-supported montmorillonite catalyst was tested as a function of nickel content, reaction temperature, naphthalene loading, and the steam to carbon ratio. The results demonstrated that montmorillonite was catalytically active in removing naphthalene. In addition, Ni-montmorillonite had very high activity towards naphthalene removal via steam reforming, with removal efficiencies of greater than 99%. The activation energy was calculated for Ni-montmorillonite assuming first order kinetics and was found to be 84.5 kJ/mole. Long-term activity tests showed that the catalyst was active with naphthalene removal efficiencies of greater than 95%, which were maintained over a 97-hour test period. Very little loss of activity was observed with a drop in removal from 97 to 95%. The drop in catalytic activity was attributed primarily to a decrease in catalyst surface area, nickel sintering, and coke formation

Catalytic Hot Gas Cleanup of Biomass Gasification Producer Gas via Steam Reforming Using Nickel-Supported Clay Minerals

Amongst the issues associated with the commercialization of biomass gasification, the presence of tars has been one of the most difficult aspects to address. Tars are an impurity generated from the gasifier and upon their condensation cause problems in downstream equipment including plugging, blockages, corrosion, and major catalyst deactivation. These problems lead to losses of efficiency as well as potential maintenance issues resulting from damaged processing units. Therefore, the removal of tars is necessary in order for the effective operation of a biomass gasification facility for the production of high-value fuel gas. The catalytic activity of montmorillonite and montmorillonite-supported nickel as tar removal catalysts will be investigated in this study. Ni-montmorillonite catalyst was prepared, characterized, and tested in a laboratory-scale reactor for its efficiency in reforming tars using naphthalene as a tar model compound. Efficacy of montmorillonite-supported nickel catalyst was tested as a function of nickel content, reaction temperature, steam-to-carbon ratio, and naphthalene loading. The results demonstrate that montmorillonite is catalytically active in removing naphthalene. Ni-montmorillonite had high activity towards naphthalene removal via steam reforming, with removal efficiencies greater than 99%. The activation energy was calculated for Ni-montmorillonite assuming first-order kinetics and was found to be 84.5 kJ/mole in accordance with the literature. Long-term activity tests were also conducted and showed that the catalyst was active with naphthalene removal efficiencies greater than 95% maintained over a 97-h test period. A little loss of activity was observed with a removal decrease from 97% to 95%. To investigate the decrease in catalytic activity, characterization of fresh and used catalyst samples was performed using thermogravimetric analysis, transmission electron microscopy, X-ray diffraction, and surface area analysis. The loss in activity was attributed to a decrease in catalyst surface area caused by nickel sintering and coke formation