Possibility of Producing Solid Paraffins by Fisher-Tropsch Synthesis in a Fixed-Bed Reactor

High pure synthetic waxes are valuable both for the separation of narrower fuel fractions by hydrorefining and for various industries, such as pharmaceuticals, cosmetics, as well as the production of thermoplastic adhesives and various polymer compositions. The work studied the possibility of obtaining high molecular weight hydrocarbons via Fischer–Tropsch synthesis in a fixed bed reactor in the presence of cobalt catalyst. The studied catalysts were synthesized on the basis of new granulated aluminum oxide, which is characterized by the presence of meso- and macropores, which is favorable for mass transfer under the synthesis conditions. The influence of the presence of spinel on the main catalytic parameters and the composition of the resulting products was also investigated, and the influence of preliminary heat treatment of the initial aluminum oxide was studied. The obtained in the presence of most promising catalysts waxes are characterized by a high degree of crystallinity, which is confirmed by diffraction data, consist predominantly of linear alkanes (the content of which is 75–80%) and contain 32–34 wt.% of C35+ hydrocarbons. Electron microscopy data of the catalyst granules clearly demonstrate that the external and internal surfaces of the catalyst are filled with solid paraffins–synthesis products–during catalytic testing, but this does not lead to its deactivation. Synthesis was performed under quite mild conditions – 170 °C, 3 MPa, which distinguishes the studied catalysts from those used in industry. The introduction of spinel into the catalyst composition did not affect its main catalytic properties. Preliminary calcination of the initial granulated aluminum oxide at 750 °C leads to a positive effect on the activity of the catalyst in the synthesis of solid paraffins. For citation: Asalieva E.Yu., Sineva L.V., Gryaznov K.O., Aksenenkov V.V., Mordkovich V.Z. Possibility of producing solid paraffins by Fisher-Tropsch synthesis in a fixed-bed reactor. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2025. V. 68. N 10. P. 95-102. DOI: 10.6060/ivkkt.20256810.22y.