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Oxidative desulfurization of jet and diesel fuels using hydroperoxide generated in situ by catalytic air oxidation / Ramanathan Sundararaman in Industrial & engineering chemistry research, Vol. 49 N° 12 (Juin 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5561–5568 Titre : Oxidative desulfurization of jet and diesel fuels using hydroperoxide generated in situ by catalytic air oxidation Type de document : texte imprimé Auteurs : Ramanathan Sundararaman, Auteur ; Xiaoliang Ma, Auteur ; Chunshan Song, Auteur Année de publication : 2010 Article en page(s) : pp. 5561–5568 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Oxidative  desulfurization  Diesel  fuels Résumé : The objective of this work is to explore the potential of carrying out oxidative desulfurization using air as an oxidant. The liquid fuels to be desulfurized were first contacted with air to produce hydroperoxides in situ, which were then used as selective oxidants to oxidize the sulfur compounds. Unsupported CuO was tested as a catalyst for producing hydroperoxides in the fuel at 120 °C in the presence of air. Air oxidation was also carried out in the presence of Al2O3-supported CuO and also noncatalytically. Unsupported CuO was substantially more active than the other two cases. The yield of the hydroperoxides depends strongly on the catalyst and the reaction temperature; the yield decreased in the order of 120 °C > 140 °C ≫ 100 °C but the rate of oxidation to produce hydroperoxides decreased in the order of 140 °C > 120 °C ≫ 100 °C. It was found that more hydroperoxides could be generated in diesel fuel than in jet fuel, which might be related to the higher concentration of alkyl aromatics in diesel fuel when compared to JP-8 jet fuel. The hydroperoxides generated in situ were then used to oxidize the sulfur compounds in the fuel in the presence of SiO2-supported MoO3 catalyst. Hydroperoxides generated in situ were effective in oxidizing the alkyl-substituted benzothiophene and dibenzothiophene present in jet and diesel fuels to their corresponding sulfones which were then removed by adsorption on beta zeolite. On the other hand, the amount of cumene hydroperoxide required per mole of S for oxidation to sulfone was 1.5 and 10 times higher than the stoichiometric amounts for JP-8 jet fuel and diesel fuel, respectively. This study demonstrates that oxidative desulfurization can be effectively carried out by using air as an oxidant for generating hydroperoxides in situ, which can then be used to selectively oxidize the sulfur compounds to sulfones, thereby eliminating the need for use, storage, and handling of expensive liquid-phase peroxide oxidants. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901812r [article] Oxidative desulfurization of jet and diesel fuels using hydroperoxide generated in situ by catalytic air oxidation [texte imprimé] / Ramanathan Sundararaman, Auteur ; Xiaoliang Ma, Auteur ; Chunshan Song, Auteur . - 2010 . - pp. 5561–5568. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5561–5568 Mots-clés : Oxidative  desulfurization  Diesel  fuels Résumé : The objective of this work is to explore the potential of carrying out oxidative desulfurization using air as an oxidant. The liquid fuels to be desulfurized were first contacted with air to produce hydroperoxides in situ, which were then used as selective oxidants to oxidize the sulfur compounds. Unsupported CuO was tested as a catalyst for producing hydroperoxides in the fuel at 120 °C in the presence of air. Air oxidation was also carried out in the presence of Al2O3-supported CuO and also noncatalytically. Unsupported CuO was substantially more active than the other two cases. The yield of the hydroperoxides depends strongly on the catalyst and the reaction temperature; the yield decreased in the order of 120 °C > 140 °C ≫ 100 °C but the rate of oxidation to produce hydroperoxides decreased in the order of 140 °C > 120 °C ≫ 100 °C. It was found that more hydroperoxides could be generated in diesel fuel than in jet fuel, which might be related to the higher concentration of alkyl aromatics in diesel fuel when compared to JP-8 jet fuel. The hydroperoxides generated in situ were then used to oxidize the sulfur compounds in the fuel in the presence of SiO2-supported MoO3 catalyst. Hydroperoxides generated in situ were effective in oxidizing the alkyl-substituted benzothiophene and dibenzothiophene present in jet and diesel fuels to their corresponding sulfones which were then removed by adsorption on beta zeolite. On the other hand, the amount of cumene hydroperoxide required per mole of S for oxidation to sulfone was 1.5 and 10 times higher than the stoichiometric amounts for JP-8 jet fuel and diesel fuel, respectively. This study demonstrates that oxidative desulfurization can be effectively carried out by using air as an oxidant for generating hydroperoxides in situ, which can then be used to selectively oxidize the sulfur compounds to sulfones, thereby eliminating the need for use, storage, and handling of expensive liquid-phase peroxide oxidants. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901812r

Selective adsorption for removal of nitrogen compounds from liquid hydrocarbon streams over carbon- and alumina-based adsorbents / Masoud Almarri in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p 951–960 Titre : Selective adsorption for removal of nitrogen compounds from liquid hydrocarbon streams over carbon- and alumina-based adsorbents Type de document : texte imprimé Auteurs : Masoud Almarri, Auteur ; Xiaoliang Ma, Auteur ; Chunshan Song, Auteur Année de publication : 2009 Article en page(s) : p 951–960 Note générale : chemical engenireeng Langues : Anglais (eng) Mots-clés : Hydrocarbon--Liquid Résumé : In order to explore the adsorptive denitrogenation of liquid hydrocarbon streams for producing ultraclean fuels, the adsorption performance of seven representative activated carbon samples and three activated alumina samples was evaluated in a batch adsorption system and a fixed-bed flow adsorption system for removing quinoline and indole from a model diesel fuel in the coexistence of sulfur compounds and aromatics. Different adsorbents show quite different selectivity toward basic and nonbasic nitrogen compounds (quinoline and indole) and sulfur compounds (dibenzothiophene and 4,6-dimethyldibenzothiophene). The activated carbons generally show higher capacity than activated alumina samples for removing the nitrogen compounds. The adsorption capacity and selectivity of the activated carbons for nitrogen compounds were further correlated with their textural properties and oxygen content. It was found that (1) the microporous surface area and micropore volume are not a key factor for removal of the nitrogen compounds in the tested activated carbons; (2) the oxygen functionality of the activated carbons may play a more important role in determining the adsorption capacity for the nitrogen compounds since the adsorption capacity for nitrogen compounds increases with increase in the oxygen concentration of the activated carbons; and (3) the type of the oxygen-functional groups may be crucial in determining their selectivity for various nitrogen or sulfur compounds. In addition, regeneration of the saturated adsorbents was conducted by the toluene washing followed by the heating to remove the remained toluene. The results show that the spent activated carbons can be regenerated to completely recover the adsorption capacity. The high capacity and selectivity of carbon-based adsorbents for the nitrogen compounds, along with their good regenerability, indicate that the activated carbons may be promising adsorbents for deep denitrogenation of liquid hydrocarbon streams. [article] Selective adsorption for removal of nitrogen compounds from liquid hydrocarbon streams over carbon- and alumina-based adsorbents [texte imprimé] / Masoud Almarri, Auteur ; Xiaoliang Ma, Auteur ; Chunshan Song, Auteur . - 2009 . - p 951–960. chemical engenireeng Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p 951–960 Mots-clés : Hydrocarbon--Liquid Résumé : In order to explore the adsorptive denitrogenation of liquid hydrocarbon streams for producing ultraclean fuels, the adsorption performance of seven representative activated carbon samples and three activated alumina samples was evaluated in a batch adsorption system and a fixed-bed flow adsorption system for removing quinoline and indole from a model diesel fuel in the coexistence of sulfur compounds and aromatics. Different adsorbents show quite different selectivity toward basic and nonbasic nitrogen compounds (quinoline and indole) and sulfur compounds (dibenzothiophene and 4,6-dimethyldibenzothiophene). The activated carbons generally show higher capacity than activated alumina samples for removing the nitrogen compounds. The adsorption capacity and selectivity of the activated carbons for nitrogen compounds were further correlated with their textural properties and oxygen content. It was found that (1) the microporous surface area and micropore volume are not a key factor for removal of the nitrogen compounds in the tested activated carbons; (2) the oxygen functionality of the activated carbons may play a more important role in determining the adsorption capacity for the nitrogen compounds since the adsorption capacity for nitrogen compounds increases with increase in the oxygen concentration of the activated carbons; and (3) the type of the oxygen-functional groups may be crucial in determining their selectivity for various nitrogen or sulfur compounds. In addition, regeneration of the saturated adsorbents was conducted by the toluene washing followed by the heating to remove the remained toluene. The results show that the spent activated carbons can be regenerated to completely recover the adsorption capacity. The high capacity and selectivity of carbon-based adsorbents for the nitrogen compounds, along with their good regenerability, indicate that the activated carbons may be promising adsorbents for deep denitrogenation of liquid hydrocarbon streams.