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Influence of Syngas Composition on the Kinetics of Fischer–Tropsch Synthesis of using Cobalt as Catalyst

Title data

Pöhlmann, Ferdinand ; Jess, Andreas:
Influence of Syngas Composition on the Kinetics of Fischer–Tropsch Synthesis of using Cobalt as Catalyst.
In: Energy Technology. Vol. 4 (2016) Issue 1 . - pp. 55-64.
ISSN 2194-4296
DOI: https://doi.org/10.1002/ente.201500216

Official URL: Volltext

Abstract in another language

A promising method for the utilization of CO₂ (e.g., captured from the flue gases of gas- or coal-based power plants) is the production of liquid hydrocarbons from CO₂ and renewable H₂ (power to liquid, PTL). This is a three-step process and consists of water electrolysis, reverse water–gas shift (RWGS), and Fischer–Tropsch synthesis (FTS). Here, the syngas for the FTS always contains CO₂ owing to the incomplete conversion of CO₂ in the RWGS reactor because of thermodynamic constraints. Therefore, the influence of not only the main reactants CO and H₂ but also CO₂ on the kinetics of FTS using a homemade cobalt catalyst was studied. Moreover, under effective conditions (i.e., with particles of millimeter size, as used in fixed-bed reactors), the FTS is affected by internal mass-transport limitations, which lead to an increased H₂/CO ratio inside the particle, which has an impact on the local reaction rate and selectivity. Therefore, the effect of the H₂/CO ratio was studied in a broad range of 0.5 to 40 at temperatures of 210 to 230 °C at a total pressure of approximately 3 MPa. With increasing H₂/CO ratio and a surplus of H₂, the methane selectivity rises and the selectivity to higher hydrocarbons decreases. As long as a certain (very low) amount of CO is present, CO₂ behaves like an inert component. However, for particle sizes of several millimeters and pronounced pore diffusion limitations, the CO concentration decreases towards the particle center and a core region free of CO is formed. At H₂/CO ratios >10, CO₂ is also converted (but practically solely to methane). The intrinsic kinetic parameters of the reaction rates were evaluated by using Langmuir–Hinshelwood-type rate expressions. The selectivities were also described by a model from Vervloet et al.1 The used models are in good agreement with the experimental results.

Further data

Item Type: Article in a journal
Refereed: Yes
Additional notes: Special Issue: Energy, Science & Technology Conference
Keywords: cobalt; carbon dioxide; hydrocarbons; reaction kinetics; syngas
Institutions of the University: Faculties
Faculties > Faculty of Engineering Science
Faculties > Faculty of Engineering Science > Chair Chemical Engineering
Faculties > Faculty of Engineering Science > Chair Chemical Engineering > Chair Chemical Engineering - Univ.-Prof. Dr.-Ing. Andreas Jess
Research Institutions > Research Units > ZET - Zentrum für Energietechnik
Research Institutions
Research Institutions > Research Units
Result of work at the UBT: Yes
DDC Subjects: 500 Science > 540 Chemistry
600 Technology, medicine, applied sciences > 600 Technology
600 Technology, medicine, applied sciences > 620 Engineering
600 Technology, medicine, applied sciences > 660 Chemical engineering
Date Deposited: 11 Feb 2016 08:06
Last Modified: 09 Nov 2022 13:30
URI: https://eref.uni-bayreuth.de/id/eprint/30606