Multidimensional modeling of a microfibrous entrapped cobalt catalyst Fischer‐Tropsch reactor bed

• Published in: AIChE journal Vol. 64; no. 5; pp. 1723 - 1731
• Main Authors: Challiwala, Mohamed Sufiyan, Wilhite, Benjamin A., Ghouri, Mohammed M., Elbashir, Nimir O.
• Format: Journal Article
• Language: English
• Published: New York American Institute of Chemical Engineers 01.05.2018
• Subjects: Carbon dioxide; Catalysis; Catalysts; Cobalt; cobalt catalyst; Computer applications; Exothermic reactions; Heat transfer; microfibrous entrapped catalyst bed; packed‐bed; Reactors; Thermal management; two‐dimensional modeling
• ISSN: 0001-1541; 1547-5905
• DOI: 10.1002/aic.16053

Thermal management of highly exothermic Fischer‐Tropsch synthesis (FTS) has been a challenging bottleneck limiting the radial dimension of the packed‐bed (PB) reactor tube to 1.5 in. ID. A computational demonstration of a novel microfibrous entrapped cobalt catalyst (MFECC) in mitigating hot spot formation has been evaluated. Specifically, a two‐dimensional (2‐D) model was developed in COMSOL®, validated with experimental data and subsequently employed to demonstrate scale‐up of the FTS bed from 0.59 to 4 in. ID. Significant hot spot of 102.39 K in PB was reduced to 9.4 K in MFECC bed under gas phase at 528.15 K and 2 MPa. Improvement in heat transfer within the MFECC bed facilitates higher productivities at low space velocities (≥1000 h−1) corresponding to high CO conversion (≥90%). Additionally, the MFECC reactor provides an eightfold increase in the reactor ID at hot spots ≤ 30 K with CO% conversions ≥ 90%. This model was developed for a typical FTS cobalt‐based catalyst where CO2 production is negligible. © 2017 American Institute of Chemical Engineers AIChE J, 64: 1723–1731, 2018