DEVELOPMENT OF SUPPORTED COBALT CATALYST FOR FISCHER-TROPSCH SYNTHESIS
| dc.contributor.advisor | Dalai, Ajay Kumar | |
| dc.contributor.advisor | Abatzoglou, Nicholas | |
| dc.contributor.committeeMember | Soltan , Jafar | |
| dc.contributor.committeeMember | Wang, Hui | |
| dc.contributor.committeeMember | Evitts, Richard | |
| dc.contributor.committeeMember | Grosvenor, Andrew | |
| dc.contributor.committeeMember | Abdelrasoul, Amira | |
| dc.contributor.committeeMember | Dadyburjor, Dady | |
| dc.creator | Vosoughi, Vahid 19760921- | |
| dc.date.accessioned | 2018-03-02T22:27:20Z | |
| dc.date.available | 2018-03-02T22:27:20Z | |
| dc.date.created | 2018-02 | |
| dc.date.issued | 2018-03-02 | |
| dc.date.submitted | February 2018 | |
| dc.date.updated | 2018-03-02T22:27:20Z | |
| dc.description.abstract | Fischer–Tropsch Synthesis (FTS) is a major part of feed-to-liquid (XTL) technologies which convert syngas (H_2+CO) into clean liquid hydrocarbon fuels and specialty chemicals. Understanding and developing FTS catalysts using mesoporous materials are of main interest in the present work. In the first step, the research focused on developing Co-based catalyst supported on multiwalled carbon nanotubes (MWCNTs). The functionalization of CNTs and its impact on the performance of corresponding catalysts on FTS were studied. Different concentrations of nitric acid were used as oxidizing agent and the higher HNO3 concentration (70 wt. %) generated more defects on the CNT walls where the Co species were located. This resulted in higher cobalt dispersion in the catalyst and correspondingly higher catalytic activity. The effects of the pelletization on the physico-chemical and mechanical properties of Fe/CNT catalyst in FTS were also investigated. Further, the limitation of N2 adsorption technique for textural characterization of CNTs was studied as compared to transmission electron microscopy. The findings of this work confirmed that the inter-tubular space between CNTs in N2 adsorption are considered in the estimation of the pore volume and average pore diameter of CNTs. Further, the high surface area and large pore size mesoporous alumina was synthesized and utilized as a support for Co catalyst. Stability of mesoporous alumina in the presence of aqueous and organic solvents during Co impregnation was examined and the corresponding catalysts were tested in FTS. Mesoporous alumina supported cobalt catalyst prepared by organic solvents (ethanol and acetone) retained the textural properties of the support, even with higher cobalt loading (30 wt. %), and resulted in better physicho-chemical and catalytic properties in FTS. Further studies were carried out to optimize the operational conditions (temperature, pressure, flow rate) for mesoporous alumina supported catalyst. Mesoporous alumina support was modified with lanthanum and cerium and their catalytic performance were investigated in FTS reaction. Furthermore, two different chelating agents (NTA and EDTA) were also incorporated to examine the possible improvement in the dispersion and reducibility of the catalysts and their performance in FTS. As a baseline for comparison, the same modification was applied to γ-alumina supported cobalt catalysts, which were characterized prior to FT reaction. Findings of this work showed that the NTA is more promising chelating agent to improve the cobalt dispersion and catalytic performance in FTS. Finally, the promoter effects on CO conversion and C5+ selectivity for mesoporous alumina supported cobalt catalyst in FTS were investigated. The addition of Mn and Y transition metals (1 % molar ratio relative to Co) led to marginal impact on Co dispersion, extent of reduction, and corresponding catalyst performance in FTS. Among the noble metal (Pt, Re, Ru, Ir) used, addition of platinum resulted in high reducibility, moderate activity, but lower C5+ selectivity and stability for FTS Co catalyst, whereas, rhenium-promoted catalyst exhibited higher C5+ selectivity, hydrocarbon productivity, and stability, as compared to Pt- and Ir-promoted catalysts. Ruthenium was found to be the most active and selective to heavier hydrocarbons, favors the catalyst stability, reducibility, and dispersion of Co significantly. | |
| dc.format.mimetype | application/pdf | |
| dc.identifier.uri | http://hdl.handle.net/10388/8459 | |
| dc.subject | Fischer-Tropsch, cobalt catalyst, carbon nanotubes, mesoporous alumina, carbon monoxide hydrogenation | |
| dc.title | DEVELOPMENT OF SUPPORTED COBALT CATALYST FOR FISCHER-TROPSCH SYNTHESIS | |
| dc.type | Thesis | |
| dc.type.material | text | |
| thesis.degree.department | Chemical and Biological Engineering | |
| thesis.degree.discipline | Chemical Engineering | |
| thesis.degree.grantor | University of Saskatchewan | |
| thesis.degree.level | Doctoral | |
| thesis.degree.name | Doctor of Philosophy (Ph.D.) |