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Alkylate technology selection for Fischer-Tropsch syncrude refining / Arno de Klerk in Industrial & engineering chemistry research, Vol. 47 N°18 (Septembre 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 N°18 (Septembre 2008) . - p. 6870–6877 Titre : Alkylate technology selection for Fischer-Tropsch syncrude refining Type de document : texte imprimé Auteurs : Arno de Klerk, Auteur ; Philip L. de Vaal, Auteur Année de publication : 2008 Article en page(s) : p. 6870–6877 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Alkylate  Fischer-Tropsch  syncrude Résumé : Technology selection to produce alkylate from straight run Fischer−Tropsch syncrude has been investigated. Alkylate is a high octane paraffinic motor-gasoline component and can be produced by direct alkylation (olefin addition to isobutane) or indirect alkylation (isobutene dimerization followed by hydrogenation). Neither isobutane nor isobutene is abundant in the light fraction of Fischer−Tropsch syncrude, which is rich in linear alpha-olefins. Direct alkylation (HF and H2SO4) and indirect alkylation (acidic resin and solid phosphoric acid) based flowschemes were evaluated in terms of alkylate yield, octane number, compatibility to Fischer−Tropsch derived feed, and environmental friendliness. It was found that the refining focus determined the selection. Indirect alkylation with solid phosphoric acid was found to be the best in terms of Fischer−Tropsch feed compatibility, environmental friendliness, and least refining complexity. The highest alkylate yield could be obtained by a combination of partial olefin hydrogenation, hydroisomerization, and direct alkylation. Butene skeletal isomerization in combination with indirect alkylation yielded an alkylate with the highest octane number. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800288n [article] Alkylate technology selection for Fischer-Tropsch syncrude refining [texte imprimé] / Arno de Klerk, Auteur ; Philip L. de Vaal, Auteur . - 2008 . - p. 6870–6877. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 N°18 (Septembre 2008) . - p. 6870–6877 Mots-clés : Alkylate  Fischer-Tropsch  syncrude Résumé : Technology selection to produce alkylate from straight run Fischer−Tropsch syncrude has been investigated. Alkylate is a high octane paraffinic motor-gasoline component and can be produced by direct alkylation (olefin addition to isobutane) or indirect alkylation (isobutene dimerization followed by hydrogenation). Neither isobutane nor isobutene is abundant in the light fraction of Fischer−Tropsch syncrude, which is rich in linear alpha-olefins. Direct alkylation (HF and H2SO4) and indirect alkylation (acidic resin and solid phosphoric acid) based flowschemes were evaluated in terms of alkylate yield, octane number, compatibility to Fischer−Tropsch derived feed, and environmental friendliness. It was found that the refining focus determined the selection. Indirect alkylation with solid phosphoric acid was found to be the best in terms of Fischer−Tropsch feed compatibility, environmental friendliness, and least refining complexity. The highest alkylate yield could be obtained by a combination of partial olefin hydrogenation, hydroisomerization, and direct alkylation. Butene skeletal isomerization in combination with indirect alkylation yielded an alkylate with the highest octane number. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800288n

Benzene reduction by alkylation in a solid phosphoric acid catalyzed olefin oligomerization process / Tebogo M. Sakuneka in Industrial & engineering chemistry research, Vol. 47 N°19 (Octobre 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 N°19 (Octobre 2008) . - p. 7178–7183 Titre : Benzene reduction by alkylation in a solid phosphoric acid catalyzed olefin oligomerization process Type de document : texte imprimé Auteurs : Tebogo M. Sakuneka, Auteur ; Reinier J. J. Nel, Auteur ; Arno de Klerk, Auteur Année de publication : 2008 Article en page(s) : p. 7178–7183 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Solid  phosphoric  acid  Benzene  Olefin  oligomerization Résumé : A refinery with a solid phosphoric acid olefin oligomerization unit can reduce the benzene content of its motor-gasoline by co-feeding the benzene-containing material to that unit. It has been shown that benzene co-feeding has little disruptive impact on olefin oligomerization, and >80% benzene conversion to alkylated benzenes has been demonstrated during a commercial test run on an industrial unit. Benzene conversion is insensitive to reactor inlet temperature in the range of 160−180 °C and remains better than 80% at liquid hourly space velocities of up to 1.5 h−1. A high propene content in the olefinic feed promotes benzene alkylation, and although butene-rich feeds can be employed, benzene conversion is lower. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800672p [article] Benzene reduction by alkylation in a solid phosphoric acid catalyzed olefin oligomerization process [texte imprimé] / Tebogo M. Sakuneka, Auteur ; Reinier J. J. Nel, Auteur ; Arno de Klerk, Auteur . - 2008 . - p. 7178–7183. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 N°19 (Octobre 2008) . - p. 7178–7183 Mots-clés : Solid  phosphoric  acid  Benzene  Olefin  oligomerization Résumé : A refinery with a solid phosphoric acid olefin oligomerization unit can reduce the benzene content of its motor-gasoline by co-feeding the benzene-containing material to that unit. It has been shown that benzene co-feeding has little disruptive impact on olefin oligomerization, and >80% benzene conversion to alkylated benzenes has been demonstrated during a commercial test run on an industrial unit. Benzene conversion is insensitive to reactor inlet temperature in the range of 160−180 °C and remains better than 80% at liquid hourly space velocities of up to 1.5 h−1. A high propene content in the olefinic feed promotes benzene alkylation, and although butene-rich feeds can be employed, benzene conversion is lower. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800672p

Dehydration of C5−C12 linear 1-alcohols over η-alumina to fuel ethers / Reinier J. J. Nel in Industrial & engineering chemistry research, Vol. 48 N° 11 (Juin 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5230–5238 Titre : Dehydration of C5−C12 linear 1-alcohols over η-alumina to fuel ethers Type de document : texte imprimé Auteurs : Reinier J. J. Nel, Auteur ; Arno de Klerk, Auteur Année de publication : 2009 Article en page(s) : pp. 5230–5238 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Linear  fuel  ethers  Olefin  dimers  Low  temperature  Fischer−Tropsch  synthesis  Alcohols Résumé : Naphtha from low temperature Fischer−Tropsch (LTFT) synthesis is rich in n-paraffins, but it also contains alcohols and olefins. These alcohols and olefins can be converted into linear fuel ethers and olefin dimers to improve the overall yield and quality of distillate from LTFT refining. The reaction network was studied for the conversion of 1-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 1-nonanol, 1-decanol, and 1-dodecanol over an η-alumina catalyst in a fixed bed flow reactor at 250−350 °C, 0−4 MPa, and WHSV of 1−4 h−1. The main products were the corresponding linear ethers and linear α-olefins. The highest ether yield (54%) was obtained at 300 °C, 1 MPa, and WHSV of 1 h−1 (unoptimized conditions). The main side-products were aldehydes and olefin dimers. Dehydration occurred predominantly on Lewis acid sites, with acid-catalyzed side-reactions taking place over Brønsted acid sites and dehydrogenation taking place over basic and/or redox sites. Dehydration to produce 2-olefins was cis-selective and occurred mainly over Lewis acid sites by dehydration−hydration−dehydration. GC-FID response factors for di-n-butyl ether and heavier linear ethers were determined experimentally. The GC-FID response factors were expressed in terms of the equivalent carbon number (ECN) concept as an ECN of −0.6 ± 0.1 for the linear ether oxygen atom, and this value could be mechanistically justified (literature ECN is −1.0). En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801930r [article] Dehydration of C5−C12 linear 1-alcohols over η-alumina to fuel ethers [texte imprimé] / Reinier J. J. Nel, Auteur ; Arno de Klerk, Auteur . - 2009 . - pp. 5230–5238. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5230–5238 Mots-clés : Linear  fuel  ethers  Olefin  dimers  Low  temperature  Fischer−Tropsch  synthesis  Alcohols Résumé : Naphtha from low temperature Fischer−Tropsch (LTFT) synthesis is rich in n-paraffins, but it also contains alcohols and olefins. These alcohols and olefins can be converted into linear fuel ethers and olefin dimers to improve the overall yield and quality of distillate from LTFT refining. The reaction network was studied for the conversion of 1-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 1-nonanol, 1-decanol, and 1-dodecanol over an η-alumina catalyst in a fixed bed flow reactor at 250−350 °C, 0−4 MPa, and WHSV of 1−4 h−1. The main products were the corresponding linear ethers and linear α-olefins. The highest ether yield (54%) was obtained at 300 °C, 1 MPa, and WHSV of 1 h−1 (unoptimized conditions). The main side-products were aldehydes and olefin dimers. Dehydration occurred predominantly on Lewis acid sites, with acid-catalyzed side-reactions taking place over Brønsted acid sites and dehydrogenation taking place over basic and/or redox sites. Dehydration to produce 2-olefins was cis-selective and occurred mainly over Lewis acid sites by dehydration−hydration−dehydration. GC-FID response factors for di-n-butyl ether and heavier linear ethers were determined experimentally. The GC-FID response factors were expressed in terms of the equivalent carbon number (ECN) concept as an ECN of −0.6 ± 0.1 for the linear ether oxygen atom, and this value could be mechanistically justified (literature ECN is −1.0). En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801930r

Nickel catalyst stability toward carboxylic acids / Andrew D. Pienaar in Industrial & engineering chemistry research, Vol. 47 n°14 (Juillet 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4962–4965 Titre : Nickel catalyst stability toward carboxylic acids Type de document : texte imprimé Auteurs : Andrew D. Pienaar, Auteur ; Arno de Klerk, Auteur Année de publication : 2008 Article en page(s) : p. 4962–4965 Note générale : Bibliogr. p. 4965 Langues : Anglais (eng) Mots-clés : Nickel  catalysts;  Carboxylic  acids Résumé : Reduced (unsulfided) nickel catalysts can be used for hydroprocessing sulfur-free Fischer−Tropsch derived feed materials, but catalyst deactivation by metal leaching can be a problem in the presence of carboxylic acids. Leaching of reduced nickel catalysts by carboxylic acids takes place by the formation of nickel carboxylates. Carboxylic acid leaching of nickel can be prevented by operating above the carboxylate decomposition temperature, which was found to be in the range 280−305 °C for the C2−C5 nickel carboxylates. Unfortunately this is not industrially practical, because of the hydrogenolysis propensity of reduced nickel catalysts at these conditions. It was also found that nickel leaching did not monotonically increase with temperature, but was inhibited at >200 °C, probably due to polymerization of the nickel carboxylates. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071628m [article] Nickel catalyst stability toward carboxylic acids [texte imprimé] / Andrew D. Pienaar, Auteur ; Arno de Klerk, Auteur . - 2008 . - p. 4962–4965. Bibliogr. p. 4965 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4962–4965 Mots-clés : Nickel  catalysts;  Carboxylic  acids Résumé : Reduced (unsulfided) nickel catalysts can be used for hydroprocessing sulfur-free Fischer−Tropsch derived feed materials, but catalyst deactivation by metal leaching can be a problem in the presence of carboxylic acids. Leaching of reduced nickel catalysts by carboxylic acids takes place by the formation of nickel carboxylates. Carboxylic acid leaching of nickel can be prevented by operating above the carboxylate decomposition temperature, which was found to be in the range 280−305 °C for the C2−C5 nickel carboxylates. Unfortunately this is not industrially practical, because of the hydrogenolysis propensity of reduced nickel catalysts at these conditions. It was also found that nickel leaching did not monotonically increase with temperature, but was inhibited at >200 °C, probably due to polymerization of the nickel carboxylates. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071628m