Fe2O3 is the major component of red mud, which is a by-produced after eluting aluminum from bauxite in the Bayer process, and can be used as an oxygen carrier. On the other hand, red mud is unsuitable for using oxygen in the crystal lattice because of its low surface
area. In this study the red-mud sample was sulfidated at high temperatures to improve the lattice oxygen mobility by forming lattice defects in the iron oxide crystals. To form crystal defects on red mud, iron oxide was converted to iron sulfide with hydrogen sulfide, and then re-oxidized
by air to remove the sulfur components. In these processes, it was possible to generate defects could be generated in the crystal structure. Crystal defects are formed by the difference in the molar volume of oxygen and sulfur bound to the metal in the oxidation-sulfidation process. The surface
area of the defective red mud increased from approximately 25.9 m2/g to 122.1 m2/g, and the pore volume increased from 0.1714cc/g to 0.2803 cc/g. In addition, the formation of crystal defects increased the oxygen transfer capacity of red mud from 1.75% to 2.25% at 15
vol.% hydrogen. This means that the amount of oxygen transported during the reduction process could be enhanced approximately 1.29 fold.
In this study, nickel-based reforming catalysts were synthesized for the reforming of toluene, a major component of thinners and widely used as an organic solvent. The reaction characteristics of these catalysts were investigated by both steam reforming and auto-thermal reforming. Reforming aromatic hydrocarbons like toluene to produce synthesis gas is difficult because carbon deposition also occurs, and the deposition of carbon lowers the activity of the catalyst and causes a pressure drop during the reaction process. In order to maintain a stable reforming process, a catalytic reaction technique capable of suppressing carbon deposition is required. Steam reforming and auto-thermal reforming of toluene were used in this study, and the temperature of the catalyst bed was remarkably reduced, due to a strong endothermic reaction during the reforming process. By using scanning electric microscopy (SEM), X-ray diffraction (XRD), and temperature-programmed oxidation analysis, it is shown that carbon deposition was markedly generated due to a catalyst bed temperature decrease. In this study, optimum conditions for catalyst composition and the reforming reaction are proposed to suppress the formation of carbon on the catalyst surface, and to remove the generated carbon from the process. In addition, ceria and zirconia were added as catalytic promoters to inhibit carbon deposition on the catalyst surface, and the carbon deposition phenomena according to the catalyst's promoter content were investigated. The results showed that the carbon deposition inhibition function of CeO 2 , via its redox properties, is insignificant in steam reforming, but is notably effective in the auto-thermal reforming of toluene.
This study examined the effects of the porosity of catalytic bag-filter materials for applications to the SNCR (selective noncatalytic reduction)-SCR (selective catalytic reduction) hybrid process for highly treating nitrogen Oxides (NOx) in the exhaust gas of a combustion
process. A V2O5/TiO2 catalyst was dispersed in a PTFE (poly-tetra-fluoro-ethylene) used as the catalytic bag-filter material to remove particulate matter and nitrogen oxides contained in the combustion exhaust gas. Macroporous alumina was added into a V2O5/TiO2-dispersed
PTFE to improve the catalytic activity of V2O5/TiO2 dispersed in the PTFE material. In this study, the textural properties and denitrification performances of the V2O5/TiO2-dispersed PTFE materials were examined according to
the addition of macro-porous alumina. When the denitrification catalyst was solely dispersed in the PTFE material, the catalyst inside the PTFE backbone had low gas-solid contact efficiency owing to the low porosity of the PTFE materials, resulting in low denitrification efficiency. On the
other hand, the catalytic activity of V2O5/TiO2 dispersed inside the macro-porous PTFE material was significantly enhanced by adding macro-porous alumina into the PTFE matrix. The enhanced textural properties of the macro-porous PTFE material where V2O5/TiO2
was uniformly dispersed proved the facilitated diffusion of combustion exhaust gas into the PTFE material.
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