EFFECT OF SUPPORT AND PROMOTERS IN FISCHER-TROPSCH SYNTHESIS USING SUPPORTED FE CATALYSTS

CANO LEONARDO; ANDRES GARCIA-BLANCO; GERMAN LENER; DEICY BARRERA; KARIM SAPAG

Cancun

Congreso; XXVI International Materials Research Congress; 2015

P { margin-bottom: 0.21cm; direction: ltr; color: rgb(0, 0, 0); line-height: 115%; widows: 2; orphans: 2; }P.western { font-family: "Calibri",sans-serif; font-size: 10pt; }P.cjk { font-family: "Calibri",sans-serif; font-size: 10pt; }P.ctl { font-family: "Times New Roman",serif; font-size: 10pt; }A:link { color: rgb(0, 0, 255); }The effect of support andactivity promoters on the catalytic properties of Fe supported in theFischer-Tropsch synthesis at high pressure, was studied. Precursorsof supported Fe on SiO2 and SBA -15 were synthesized.These were doped with Cu to increase the activity and stability andwhit K to increase selectivity towards olefins. The precursors wereactivated in pure H2 stream and catalytically tested witha mixture of H2: CO = 2:1, TR = 543 K and 10 bar ofpressure. The samples were characterized by atomic absorption, UV-Visspectroscopy, N2 adsorption, X-ray diffraction, TEMspectroscopy, TPD-CO2, TPH and Mössbauer spectroscopy.Also, we use the Density Functional Theory to study the promoterseffects over the CO adsorption in the active sites. The incorporationof different ions in the precursors do not alter the structural andtextural properties of the mesoporous support. The activated solidsshow the same Fe species: Fe2 + diffused in the SBA-15 andSiO2 walls, Fe3O4, α-Fe and Fe2SiO4although in different percentages according to the dopant present. Inthe Fischer Tropsch synthesis using all catalysts supported on SBA-15was obtained very low methane selectivity and a promising hydrocarbonproduction in the range of gasoline showing the effect of the supportfor this reaction. The activity order obtained in the Fischer Tropschsynthesis was: Fe-K-SBA-15> Fe-Cu-SBA-15 ≈ Fe-SBA-15 >Fe-SiO2 and it?s the same order for the selectivitytowards olefins. The difference between the catalysts confirms thatthe presence of the K cations on the SBA-15 surface increases theactivity and selectivity towards olefins; these indicate theelectrostatic effect generated by the alkaline ions.