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    Catalyst preparation and testing for catalytic combustion of chloromethanes
    (Springer, 2002) Atalay, S; Alpay, HE; Atalay, FS; Derouane, EG; Parmon, V; Lemos, F; Ribeiro, FR
    The catalytic combustion of methylenechloride, carbontetrachloride, and chloroform, three of the chloromethanes, was investigated on metal oxide catalysts prepared on the monolith support or on the spherical alumina pellets. The prepared catalysts were tested for methylenechloride and carbontetrachloride at the different temperatures and at varying GHSV values with an excess air ratios of 216% and 3100%, respectively. The catalyst having the composition of 15% Cr2O3, 5% Ce2O3 and 80% gamma-Al2O3 on the monolith was found to be ultimate due to the complete destruction of methylenechloride and to the highest mechanical stability. The operating conditions were proposed as 77778 h(-1) for the GHSV, 216% for the excess air and 400-500degreesC for the temperature range to combust methylenechloride completely. However the catalyst with a different active part composition (18% Cr2O3, 2% Ce2O3) satisfied nearly complete destruction of carbontetrachloride. The operating conditions were 5702 h(-1) for the GHSV, 3100% for the excess air ratio and 800degreesC for the temperature to combust carbontetrachloride. The catalytic oxidation of chloroform was investigated by the catalyst having the composition of 18% Cr2O3, 2% of Ce2O3 on monolith. The excess air was kept at a value of 4077%. The reactor temperature was changed between 200 and 300degreesC.
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    Catalytic combustion of carbon tetrachloride
    (Elsevier Science Bv, 2002) Tanilmis, T; Atalay, S; Alpay, HE; Atalay, FS
    The catalytic combustion of carbon tetrachloride (CCl4) by metal oxide catalysts coated on the monolith support was investigated. The prepared catalysts were tested at temperatures between 300 and 800degreesC and at varying gas hourly space velocity (GHSV) values with an excess air ratio of 3100%. The catalyst, whose composition was 18% Cr2O3, 2% Ce2O3 and 80% gamma-Al2O3, was found to almost completely oxidize CCl4. The operating conditions proposed are 5702h(-1) for GHSV, 3100% excess air and a temperature slightly higher than 800degreesC. The reaction rate expression was found to be independent of oxygen partial pressure but strongly dependent on CCl4 partial pressure. (C) 2002 Elsevier Science B.V. All rights reserved.
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    Catalytic combustion of carbontetrachloride
    (Battelle Press, 1998) Atalay, S; Tanilmis, T; Alpay, HE; Atalay, FS; Wickramanayake, GB; Hinchee, RE
    The catalytic combustion of carbontetrachloride was investigated on metal oxide catalysts coated on the monolith support. The prepared catalysts were tested at the different temperatures between 300 and 800 degrees C and the varying GHSV values with an excess air ratio of 3100%. The catalyst, having the composition of 18% Cr2O3, 2% Ce2O3 and 80% gamma-Al2O3, was found to be suitable for the almost complete destruction of carbontetrachloride. The operating conditions were proposed as 5702 h(-1) for GHSV, 3100% for the excess air. The temperature should be slightly higher than 800 degrees C. The reaction rate expression was found to be independent of oxygen partial pressure and strongly dependent on carbontetrachloride partial pressure.
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    Catalytic combustion of methylenechloride
    (Gordon Breach Sci Publ Ltd, 1996) Ballikaya, M; Atalay, S; Alpay, HE; Atalay, FS
    The catalytic combustion of methylenechloride, one of the chloromethanes, was investigated on metal oxide catalysts coated on the monolith support or on the spherical alumina pellets. The prepared catalysts were tested at the different temperatures between 200 and 500 degrees C and at varying GHSV values with an excess air of 216%. The catalyst having the composition of 15% Cr2O3, 5% Ce2O3 and 80%gamma-Al2O3 on the monolith was found to be ultimate due to the complete destruction of methylenechloride and to the highest mechanical stability. The operating conditions were proposed as 77778 h(-1) for the GHSV, 216% for the excess air and 400-500 degrees C for the temperature range to combust methylenechloride completely. The dependency of the reaction on methylenechloride and oxygen partial pressures was searched, and it was determined that the rate was strongly dependent on oxygen partial pressure and weakly methylenechloride partial pressure. The reaction rate expression was derived using the mechanism proposed by Downie and the reoxidation and reduction rate constants of the reaction were found as: k(i) = 4.422 x 10(-5)exp(-12597.5/RT) K-0 = 2.901 x 10(-6)exp(-4552.5/RT).
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    Fermentation of organic solid wastes as a source of renewable energy
    (Battelle Press, 1999) Atalay, FS; Yilmaz, AH; Alleman, BC; Leeson, A
    As a result of anaerobic fermentation of biodegradable organic wastes, a gas mixture containing methane and carbon dioxide mainly, is produced. The organic complex solid wastes that might be harmful for human can be treated using the anaerobic fermentation process producing useful energy and also fertiliser. In this study, methane production from six different solid wastes was investigated using six small batch laboratory fermenters each of that had a volume of 10 liters and a pilot scale fermenter which had a volume of 0.96 m(3). All experiments were performed at 35 degrees C, and the results were applied to the different microbial kinetics that are indicated in literature.
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    Modeling of the anaerobic decomposition of solid wastes
    (Taylor & Francis Inc, 2003) Yilmaz, AH; Atalay, FS
    When biodegradable organic wastes decompose under anaerobic conditions, a gas mixture containing mainly methane and carbon dioxide is produced. Thus an organic complex waste that might be harmful for humans can be treated by anaerobic digestion. The gas generated by anaerobic digestion of organic wastes is called biogas. Since it contains methane, it can be burned, so it can be used as an alternative energy source. In order to design an anaerobic fermenter, micro-organism growth kinetics and substrate consuming and gas production rates should be determined. In this study, biogas production from 5 different organic solid wastes was investigated by using 6 batch laboratory fermenters. The results of the experiments were tested on the 6 different microbial kinetics indicated in the literature and the best-fitting model relating the specific growth rate of micro-organisms for each solid waste was determined by a nonlinear regression method.
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    Modeling of the anaerobic decomposition of solid wastes
    (Taylor & Francis Inc, 2003) Yilmaz, AH; Atalay, FS
    When biodegradable organic wastes decompose under anaerobic conditions, a gas mixture containing mainly methane and carbon dioxide is produced. Thus an organic complex waste that might be harmful for humans can be treated by anaerobic digestion. The gas generated by anaerobic digestion of organic wastes is called biogas. Since it contains methane, it can be burned, so it can be used as an alternative energy source. In order to design an anaerobic fermenter, micro-organism growth kinetics and substrate consuming and gas production rates should be determined. In this study, biogas production from 5 different organic solid wastes was investigated by using 6 batch laboratory fermenters. The results of the experiments were tested on the 6 different microbial kinetics indicated in the literature and the best-fitting model relating the specific growth rate of micro-organisms for each solid waste was determined by a nonlinear regression method.