ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Kinetic estimation of Fischer–Tropsch synthesis using biogas-derived feedstocks over Ni/Al₂O₃ catalyst

Nabil Majd Alawi, Firas Khaleel AL-Zuhairi, Hoang M. Nguyen, Hassan H. Al-Mohammedawi, and Jamal M. Ali

Chemical Engineering Department, University of Technology- Iraq, Baghdad, Iraq

E-mail: nabil.m.alawi@uotechnology.edu.iq

Received: 25 July 2023  Accepted: 1 September 2023

Abstract:

In this study, the kinetics of the Fischer–Tropsch process synthesis (also known as FTS) was investigated using feedstocks produced from biogas. For the kinetic testing, a differential fixed-bed reactor was utilized to operate the Ni/Al₂O₃ catalyst produced using precipitation procedures. Experiments were carried out with a variety of settings for the working circumstances, such as reaction temperatures ranging from 543 to 563 °K, H₂:CO ratios ranging from 0.5 to 3, a pressure of 3.0 megapascals, with a gas hourly space velocity of 3500 (1/h). The reaction kinetics within this range of conditions can be modeled in a precise and accurate way thanks to the derived kinetic parameters. The FTS reaction hypothesized mechanism uses the Langmuir–Hinshelwood–Hougen–Watson theory, which predicts that carbon monoxide and hydrogen will have an adsorption behavior. The kinetic data obtained in this investigation were effectively modeled using a straightforward equation, which is as follows: \(- r_{{{\text{CO}}}} = \frac{{k \cdot P_{{{\text{CO}}}}^{n} \cdot P_{{{\text{H}}_{2} }}^{m} }}{{(1 + {\text{K}} \cdot \left( {a_{{{\text{CO}}}} \cdot P_{{{\text{CO}}}}^{n} + a_{{{\text{H}}_{2} }} \cdot P_{{{\text{H}}_{2} }}^{m} } \right)^{2} )}}\). This model implies that essential kinetic processes, such as CO-dissociation by contact with adsorbed hydrogen, have already occurred. The first stage in the hydrogenation process is presumed to be fast and reversible, whereas the second step is presumed to be sluggish and rate-determining.

Keywords: Biogas; Fischer–Tropsch synthesis; Nickel/Alumina catalyst; Kinetic model

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-023-03054-1

Chemical Papers 77 (12) 7615–7623 (2023)