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154. The oxidation of granular activated carbon below the spontaneous ignition temperature
142
Abstracts
simplified form to predict the changes of the gas transport properties of two different graphites and is shown to give good agreement with experiment. A more sophisticated version of the model is described based on a computer model of the changes in an arbitrary pore size distribution with radiolytic oxidation-“Graphox”. 153. Formation of stable oxygen complexes during tbe gasificationof char in air at 64ltK R. L. Taylor and P. L. Walker, Jr. (Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA 16802). The formation of surface complexes on active sites during the reaction of Saran char with air at 648K has been investigated. The oxygen complexes were thermally desorbed up to 1223K as CO and CO2 following gasification of the char to different levels of burn-off. Areas occupied by the complex increased with burn-off and at burn-offs above 70% exceeded total surface area estimated from physical gas adsorption. 154. Tbe oxidation of granular activated carbon below the spontaneousi&ion temperature Victor R. Deitz (Naval Research Laboratory, Washington, DC20375). The oxidation in excess air of granular charcoals was followed at constant temperature (150 to 300°C) and at constant oxygen concentration (1, lo,20 and 100%). The emission of carbon monoxide and carbon dioxide were also determined in nitrogen and in helium. The burn-off to CO and COZ was handled separately. Linear graphs of in rate vs l/T were obtained having a temperature coefficient corresponding to a heat of 49Kcal/mole. A model is suggested based on the formation and decomposition of the surface-oxide complex which remains intact up to the spontaneous ignition temperature.
TROGRAPHIT GMBH, Werk Griesheim, Stroofstr. 27, D 6230 Frankfurt 80, Germany). The calcining atmosphere gives the possibility to optimize the energy demand of the calcining process for coke. Furthermore it can be shown that the high temperature oxidation has a stronger effect on the surface and pore morphology whereas the low temperature oxidation changes only the surface chemistry.
157. The relationship between opticnl texture and CO2 reactivity of qetaRnrgIcaI coke Seiji Nishida, Hideo Fujita and Mitsumasa Hijiriyama (Research Laboratory, The Kansai Coke and Chemicals Company, 5, Misono-cho, Amagasaki, Hyogo, Japan). 14 rank coals were carbonized individually and three optical texture contents of the obtained cokes before and after COZ reaction at 1100°C were determined. It was found that the relative CO2 reactivity of the optical textures, i.e. flow type, mosaic texture and isotropic texture, was nearly equal to 1:2: 3.
158. Mathematical models and experimental measurements of coke reactivity D. A. Aderibigbe and J. Szekely (Department of Materials Science and Engineering, Massachusetts Znstitute of Technology, Cambridge, MA 02139). The reaction of a metallurgical coke in a simulated iron blast furnace environment of CO/C02/N2 and at temperatures between 750 and 1060°C has been investigated using single coke specimens in a thermogravimetric arrangement. The implications of the non-isothermal conditions on the reactivity of the coke in the stack region are discussed.
159. Tbe reaction of metallurgical cokes of different optf155. An electron microscopic and X-ray photoelectron cal textures witb KOH spectroscopicstudy of calcfned and partially gasified H. Marsh and A. Wilkinson (Northern Carbon nickel containing chars Research Laboratories, School of Chemistry, University T. Wigmans, K. Auwerda and J. A. Moulijn (Institute of Newcastle upon Tyne, Newcastle upon Tyne, NE1 for Chemical Technology, Universityof Amsterdam, The 7RU, England). The presence of alkali material in a blast Netherlands) and J. W. Geus (Division of Inorganic furnace is known to be detrimental to coke performance. Chemistry, University of Utrecht, The Netherlands). In This study examines the interaction of KOH with five this paper results are presented of an electron micrometallurgical cokes of increasing content of anisotropic scopic study (TEM, STEM and SEM) on the influence of carbon. The extent of pitting and fissuring of these cokes heat treatment and gasification conditions on the strucleading to fragmentation increases with * increasing ture of nickel containing activated carbon and medium anisotropic content. Potassium is able to diffuse into the volatile coal. It is shown that initial porosity, gasifying interior of coke particles. medium and reaction temperature highly influence the sintering rate of nickel particles. In a steam atmosphere sintering occurs much more rapidly than in an inert or 160. SEM study of tbe reaction of KNO, with charcoals hydrogen atmosphere. Samples, in which sintering has and anisotropicawbous taken place, show a nickel enrichment at the outer surE. McAuliffe, J. Griffiths and H. Marsh (Northern face of the carbon particles observed. This is also Carbon Research Laboratories, School of Chemistry, confirmed by XPS measurements. University of Newcastle upon Tyne, Newcastle upon Tyne, NE1 7RU, England). Charcoals were prepared from 156. The release of volatile matter from green coke during hard and soft woods. Two petroleum cokes were studied calcinatfon as a function of temperatureand atmos- for comparison purposes. Prepared surfaces of the carphere bons were examined by SEM before and after reaction H. Tillmanns, U. Braun and H. Pauls (SZGRZELEKwith solid KNOs at temperatures reaching l273K in an
Abstracts
simplified form to predict the changes of the gas transport properties of two different graphites and is shown to give good agreement with experiment. A more sophisticated version of the model is described based on a computer model of the changes in an arbitrary pore size distribution with radiolytic oxidation-“Graphox”. 153. Formation of stable oxygen complexes during tbe gasificationof char in air at 64ltK R. L. Taylor and P. L. Walker, Jr. (Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA 16802). The formation of surface complexes on active sites during the reaction of Saran char with air at 648K has been investigated. The oxygen complexes were thermally desorbed up to 1223K as CO and CO2 following gasification of the char to different levels of burn-off. Areas occupied by the complex increased with burn-off and at burn-offs above 70% exceeded total surface area estimated from physical gas adsorption. 154. Tbe oxidation of granular activated carbon below the spontaneousi&ion temperature Victor R. Deitz (Naval Research Laboratory, Washington, DC20375). The oxidation in excess air of granular charcoals was followed at constant temperature (150 to 300°C) and at constant oxygen concentration (1, lo,20 and 100%). The emission of carbon monoxide and carbon dioxide were also determined in nitrogen and in helium. The burn-off to CO and COZ was handled separately. Linear graphs of in rate vs l/T were obtained having a temperature coefficient corresponding to a heat of 49Kcal/mole. A model is suggested based on the formation and decomposition of the surface-oxide complex which remains intact up to the spontaneous ignition temperature.
TROGRAPHIT GMBH, Werk Griesheim, Stroofstr. 27, D 6230 Frankfurt 80, Germany). The calcining atmosphere gives the possibility to optimize the energy demand of the calcining process for coke. Furthermore it can be shown that the high temperature oxidation has a stronger effect on the surface and pore morphology whereas the low temperature oxidation changes only the surface chemistry.
157. The relationship between opticnl texture and CO2 reactivity of qetaRnrgIcaI coke Seiji Nishida, Hideo Fujita and Mitsumasa Hijiriyama (Research Laboratory, The Kansai Coke and Chemicals Company, 5, Misono-cho, Amagasaki, Hyogo, Japan). 14 rank coals were carbonized individually and three optical texture contents of the obtained cokes before and after COZ reaction at 1100°C were determined. It was found that the relative CO2 reactivity of the optical textures, i.e. flow type, mosaic texture and isotropic texture, was nearly equal to 1:2: 3.
158. Mathematical models and experimental measurements of coke reactivity D. A. Aderibigbe and J. Szekely (Department of Materials Science and Engineering, Massachusetts Znstitute of Technology, Cambridge, MA 02139). The reaction of a metallurgical coke in a simulated iron blast furnace environment of CO/C02/N2 and at temperatures between 750 and 1060°C has been investigated using single coke specimens in a thermogravimetric arrangement. The implications of the non-isothermal conditions on the reactivity of the coke in the stack region are discussed.
159. Tbe reaction of metallurgical cokes of different optf155. An electron microscopic and X-ray photoelectron cal textures witb KOH spectroscopicstudy of calcfned and partially gasified H. Marsh and A. Wilkinson (Northern Carbon nickel containing chars Research Laboratories, School of Chemistry, University T. Wigmans, K. Auwerda and J. A. Moulijn (Institute of Newcastle upon Tyne, Newcastle upon Tyne, NE1 for Chemical Technology, Universityof Amsterdam, The 7RU, England). The presence of alkali material in a blast Netherlands) and J. W. Geus (Division of Inorganic furnace is known to be detrimental to coke performance. Chemistry, University of Utrecht, The Netherlands). In This study examines the interaction of KOH with five this paper results are presented of an electron micrometallurgical cokes of increasing content of anisotropic scopic study (TEM, STEM and SEM) on the influence of carbon. The extent of pitting and fissuring of these cokes heat treatment and gasification conditions on the strucleading to fragmentation increases with * increasing ture of nickel containing activated carbon and medium anisotropic content. Potassium is able to diffuse into the volatile coal. It is shown that initial porosity, gasifying interior of coke particles. medium and reaction temperature highly influence the sintering rate of nickel particles. In a steam atmosphere sintering occurs much more rapidly than in an inert or 160. SEM study of tbe reaction of KNO, with charcoals hydrogen atmosphere. Samples, in which sintering has and anisotropicawbous taken place, show a nickel enrichment at the outer surE. McAuliffe, J. Griffiths and H. Marsh (Northern face of the carbon particles observed. This is also Carbon Research Laboratories, School of Chemistry, confirmed by XPS measurements. University of Newcastle upon Tyne, Newcastle upon Tyne, NE1 7RU, England). Charcoals were prepared from 156. The release of volatile matter from green coke during hard and soft woods. Two petroleum cokes were studied calcinatfon as a function of temperatureand atmos- for comparison purposes. Prepared surfaces of the carphere bons were examined by SEM before and after reaction H. Tillmanns, U. Braun and H. Pauls (SZGRZELEKwith solid KNOs at temperatures reaching l273K in an