The use of hydrotalcite derived catalyst precursors in the Fischer-Tropsch synthesis

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dc.contributor.advisorVan Steen, Ericen_ZA
dc.contributor.advisorBromfield, Tracyen_ZA
dc.contributor.authorNaidoo, Thiloshinien_ZA
dc.date.accessioned2014-07-31T11:14:57Z
dc.date.available2014-07-31T11:14:57Z
dc.date.issued2007en_ZA
dc.descriptionIncludes bibliographical references (leaves 92-96).
dc.description.abstractThe current fused iron catalyst used in the high temperature Fischer-Tropsch process is not very responsive to chemical promotion. Thus the optimisation of the selectivity of this catalyst is restricted. In the development of a catalyst the aim is to obtain the best combination of activity, selectivity and stability with the optimum number of effective active sites of the catalyst exposed to the reaction medium [Gibson, 1999]. Catalysts that have a large catalytically active surface area exposed to the reaction can be obtained by having very small catalyst particles well dispersed on a support material [Augustine, 1996]. Supporting the iron metal used in the HTFT process onto a basic support should eliminate the problem associated with supported iron catalysts namely, the effect of "alkali dilution" caused by the migration of the alkali onto the support material [Dry,1981 ]. Hydrotalcites have been shown to provide a high surface area basic support [Schaper, 1989]. Supporting the iron metal used in Fischer-Tropsch synthesis onto the basic hydrotalcite eliminates the problems associated with supported alkali promoted iron catalyst and results in a catalyst system that can be controlled and optimised to produce catalysts with specific compositions and characteristics. Alternatively, the iron can be incorporated into the hydrotalcite structure to form an Mg-Fe hydrotalcite. This allows for interaction between the elements which may result in possible synergistic effects.The use of a Mg-Fe hydrotalcite in the Fischer-Tropsch synthesis was investigated in this study. Mg-Fe hydrotalcites were prepared with a molar ratio of Mg to Fe of 2:1. The catalyst was thereafter heat treated and activated prior to synthesis. The hydrotalcite derived catalyst showed an overall CO conversion of ca. 75% and conversion to FT products of ca. 40%. The performance was comparable to that of a standard fused catalyst which is typically used in the High Temperature Fischer-Tropsch process.en_ZA
dc.identifier.apacitationNaidoo, T. (2007). <i>The use of hydrotalcite derived catalyst precursors in the Fischer-Tropsch synthesis</i>. (Thesis). University of Cape Town ,Faculty of Engineering & the Built Environment ,Department of Chemical Engineering. Retrieved from http://hdl.handle.net/11427/5431en_ZA
dc.identifier.chicagocitationNaidoo, Thiloshini. <i>"The use of hydrotalcite derived catalyst precursors in the Fischer-Tropsch synthesis."</i> Thesis., University of Cape Town ,Faculty of Engineering & the Built Environment ,Department of Chemical Engineering, 2007. http://hdl.handle.net/11427/5431en_ZA
dc.identifier.citationNaidoo, T. 2007. The use of hydrotalcite derived catalyst precursors in the Fischer-Tropsch synthesis. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Naidoo, Thiloshini AB - The current fused iron catalyst used in the high temperature Fischer-Tropsch process is not very responsive to chemical promotion. Thus the optimisation of the selectivity of this catalyst is restricted. In the development of a catalyst the aim is to obtain the best combination of activity, selectivity and stability with the optimum number of effective active sites of the catalyst exposed to the reaction medium [Gibson, 1999]. Catalysts that have a large catalytically active surface area exposed to the reaction can be obtained by having very small catalyst particles well dispersed on a support material [Augustine, 1996]. Supporting the iron metal used in the HTFT process onto a basic support should eliminate the problem associated with supported iron catalysts namely, the effect of "alkali dilution" caused by the migration of the alkali onto the support material [Dry,1981 ]. Hydrotalcites have been shown to provide a high surface area basic support [Schaper, 1989]. Supporting the iron metal used in Fischer-Tropsch synthesis onto the basic hydrotalcite eliminates the problems associated with supported alkali promoted iron catalyst and results in a catalyst system that can be controlled and optimised to produce catalysts with specific compositions and characteristics. Alternatively, the iron can be incorporated into the hydrotalcite structure to form an Mg-Fe hydrotalcite. This allows for interaction between the elements which may result in possible synergistic effects.The use of a Mg-Fe hydrotalcite in the Fischer-Tropsch synthesis was investigated in this study. Mg-Fe hydrotalcites were prepared with a molar ratio of Mg to Fe of 2:1. The catalyst was thereafter heat treated and activated prior to synthesis. The hydrotalcite derived catalyst showed an overall CO conversion of ca. 75% and conversion to FT products of ca. 40%. The performance was comparable to that of a standard fused catalyst which is typically used in the High Temperature Fischer-Tropsch process. DA - 2007 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2007 T1 - The use of hydrotalcite derived catalyst precursors in the Fischer-Tropsch synthesis TI - The use of hydrotalcite derived catalyst precursors in the Fischer-Tropsch synthesis UR - http://hdl.handle.net/11427/5431 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/5431
dc.identifier.vancouvercitationNaidoo T. The use of hydrotalcite derived catalyst precursors in the Fischer-Tropsch synthesis. [Thesis]. University of Cape Town ,Faculty of Engineering & the Built Environment ,Department of Chemical Engineering, 2007 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/5431en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDepartment of Chemical Engineeringen_ZA
dc.publisher.facultyFaculty of Engineering and the Built Environment
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherChemical Engineeringen_ZA
dc.titleThe use of hydrotalcite derived catalyst precursors in the Fischer-Tropsch synthesisen_ZA
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationnameMScen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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